the Institute of Physical and Chemical Research
Wako-shi, Saitama Pref., JAPANIPCR cyclotron
Progress Report 1971

Vol. 5

Edited by Administration Committee of the IPCR Cyclotron,peR

Cyclotron Progress Report 1971

Vol. 5The Institute of Physical and Chemical Research"RIKAGAKU KENKYUSHO" Wako-shi, Saitama, 351 JAPAN
December, 1971

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

This volume is dedicated to the memory of
Dr. Kazuhisa Matsuda

Kazuhisa

Matsuda1922-1971

KAZUHISA MATSUDA

In the midst of a full life, Kazuhisa Matsuda, chief of the Cyclotron
Laboratory, the Institute of Physical and Chemical Research, died on 29
March at the age of 48 due to an accident. Deeply grieved, his colleagues l suddenly lost a devoted friend who was a great leader in the !
field of nuclear physics in Japan.
He, graduated from the University of Tokyo in 1946, started hislife as a scientist at Tokyo Institute of Technology. When the plan of
construction of a new cyclotron at the Institute for Nuclear Study,
University of Tokyo, started, he joined the construction group andplayed an important role to realize the variable-energy cyclotron.
Then he woked mainly on the direct nuclear reactions, at first theelastic and inelastic scattering of protons on light and medium weight
nuclei and then the transfer reactions. He was one of the pioneers who
showed the existence of the resonance structure in the intermediate
energy region.
He was also distinguished in developing the experimental technology. He designed the high resolution particle analyzers for INS FF and
FM cyclotron with which valuable data on nuclear structure have beenobtained.
In 1964 he joined the cyclotron laboratory of IPCR to construct
the new cyclotron. Here he was a leader of the machine developinggroup and the nuclear physics group.
For a long time he was the chairman of the low energy nuclear
physics committee in Japan and made efforts to construct the new AVF
cyclotron in Osaka.
There was much that Kazuhisa Matsuda wanted to do if the sudden
end of his life did not come. The warmth of his presence is bitterly
missed but he has left the lasting imprint of his personality on whole
who are acquainted with him.

CONTENTS

Page
1.

INTRODUCTION ........................................................................ .

1

2.

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

2

3.

MACHINE DEVELOPMENT AND ACCELERATOR PHYSICS
3-1.

3-2.

3-3.

3-4.

3-5.

3-6.

4.

Production of Multiply-Charged Ions of Ne, Ar , Kr , and
Xe by the Electron-Bombarded Hot Cathode Ions Source

5

Charge Exchange Experiment (3)Cross Sections for Electron Loss and Capture of
Nitrogen Ions in Various Gases ............................... ..

11

Acceleration of Tritium Ions and Measurements ofResidual Tritium in the Cyclotron ................................... ..

16

Design of the Power Supply Distributor for the
Beam Handling System of Cyclotron ................................. ..

19

Safety Devices of the Beam Handling System to Prevent
Radiation Hazard and Vacuum Trouble ............................. ..

22

Improvement of the Beam -Handling System for
Experiments of Nuclear Physics ...................................... ..

25

NUCLEAR PHYSICS
Scattering and Reactions
4-1.

27 Al ( 12 C, lIB) 28 Si and 27 Al ( 12 C, 13N) 26 Mg Reactions

28

4 -2.

The 100,98 Mo (t, p) 102,100 Mo Reactions and Low-Lying
0+ States in Even Molybdenum Isotopes ............................ ..

31

4-3.

The 27 Al (3He, p) 29 Si Reaction at 21. 89 MeV..................... ..

35

4-4.

Elastic Scattering of Alpha Particles fromEven-Mass Molybdenum Isotopes ..................................... ..

38

The Manual of the Code for the ;Form Factor Computationof the Two - Nucleon Transfer Reaction ............................. ..

40

4-6.

The Spin-Flip Probability in the 92,94Mo (p, p ' ) Reaction ........

42

4-7.

Spin Flip in the Inelastic Scattering of 3He on 12C .............. ..

44

4-5.

5.

NUCLEAR PHYSICS
Nuclear Spectroscopy
5-1.

6.

The Level Structures of Light Even Strontium Isotopes
Produced by 70,72,74,76Ge ( 12 C, 4n) Reactions .................... .

46

5-2.

Magnetic Moment of the 8+ State of 206 po ........................... .

51

5-3.

Magnetic Moment of the Lowest 6+ State in 42Ca ................. .

54

5-4.

Decay of 87 Zr and 85Zr .................................................. .

57

5-5.

New Isomer in 148Gd ...................................................... .

63

NUCLEAR INSTRUMENTATION
6-1.

7.

Development of a Wire Spark Chamber with Ferrite Cores
for a Broad Range Magnetic Spectrometer ......................... ..

68

6-2.

A Mechanical Beam Chopper for Millisecond Beam Pulsiflg .....

72

6-3.

A r -Ray Spectrometer for Nuclear Study .......................... ..

75

6-4.

Data Processor .............................................................. .

78

RADIOCHEMISTRY
7 -1.

Chen'lical Behavior of Carbon in Semiconductor Siliconin the Dissolution and Fusion of the Matrix ........................ ..

80

7 -2.

Excitation Function for Some Triton -induced Reactions .........

83

7 -3.

A Mossbauer Spectroscopic Study of Chemical Statesof 119Sn after EC Decay of 119 Sb in Antimony
Chalcogenides ............................................................... .

85

Charge States of Ions Produced by the Decay of 18 F ............. .

88

7 -4.
8.

9.

RADIATION CHEMISTRY AND RADIATION BIOLOGY
8 -1.

Radiolysis of Ketones in High LET Region .......................... .

90

8-2.

LET Effect in the Radiolysis of Some Organic Liquids ......... ..

93

8 -3.

LET Effects on Bacterial Cells ......................................... .

95

SOLID STATE PHYSICS
9-1.

Electron Microscopic Observation on Helium Bubbles
in Aluminum Irradiated by Alpha - Particles ......................... .

98

10.

9-2.

Point Defects in Irradiated Copper and CU3Au ..................... .

101

9-3.

Polarized Positron Annihilation in Ferromagnetic Nickel ....... .

105

RI PRODUCTION AND ITS APPLICATIONS
10-1.

11.

Production of Radioisotope for Medical andAgricultural Use ............................................................ .

109

RADIATION MONITORING
11-1.

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

110

11-2.

Individual Monitoring for Internal Contamination
with Tritium ................................................................. .

III

12.

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

114

13.

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

116

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

119

1

1. INTRODUCTION

The participation of scientists of diverse fields in the research work witha large experimental facility such as cyclotron usually presents numerous difficulties
concerning the use of machine and relevant instruments. In the research ensemble
using our cyclotron, however, these difficulties are set aside step by step withaccumulation of valuable experiences, and well-balanced developments in all fields ofresearch are realized as seen in this report.
It is one of the remarkable features of the machine that one and the sametarget can be easily bombarded with different projectiles. The inelastic scattering of
protons and alpha particles on molybdenum isotopes was thus found to give different ;32
values for the different projectiles. After the test runs made twice in the preceding
period, tritium ions were accelerated up to 24 MeV for the first time in the cyclotron.
(t,p) Refactions on lOOMo and 98 Mo and isotope production by tritons were studied.
Many kinds of radioisotopes were produced by the procedures developed here andsupplield for use in medical and other fields. The energy dependence of the single
transfer reaction with heavy ions was investigated. Use of heavy ions for the studiesof radiation chemistry and radiation biology revealed a new process in the radiolysis
of solution under large LET and an important role of delta rays in the radiation effecton bacteria was suggested. A simulation study of the radiation damage of nuclear fuelcasing is being made in cooperation with the Japan Atomic Energy Research Institute.
The need for a large modification or innovation of the accelerator and otherfacilities has been foreseen in these several years and investigations of various
possibilities thereof are under way, though not mentioned in this report.
It is our great regret that we have lost our colleague K. Matsuda who was tosucceed H. Kumagai as chief of the Cyclotron Laboratory and to lead the work on
the accelerator as well as on nuclear phYSics.

Tatsuji Hamada, Chairman
Administration Committee of
the IPCR Cyclotron

2

2. MACHINE OPERA liON

Machine Group

During the interval from Nov. 1970 to Oct. 1971 the cyclotron was operated bya full-time system without any serious difficulty. There was a 5 -day stoppage in
April 1971 on account of K. Matsuda's sudden death. Modification of the target areafor nuclear scattering forced extension of the summer shutdown by a week . In spiteof these unusual circumstances and a shorter period than ordinary years by one monthfor taking statistics, the total hours of "on beam" had amounted to 4 579 h as listed
in Table 1. This will be increased over 5200 h in the 12-month base and nearly
the same with that of the last year.
Scheduled machine time and subject of research are indicated in Table 2. The"on beam" time is about 86 % of the scheduled machine time. This means that over
95 % of the schedule has been fulfilled. The machine time reserved for machineinspection and repair or time for ion source exchange does not need bean1. A machine
improvement and maintenance group was formed, and began activity in May in collaboration with the operating crew. Material reserve of proper quantity for repair andTable 1.

Machine operation time by working tilne meter.

Date

Oscillator on

Ion source on

Nov. 19, 1970

17539.1 (h)19166.6 (h)Oct. 20, 1971

22118.0 (h)24204.8 (h)336 days4578.9 (h)5038.2 (h)Percent of 336 days

56.8

%

62.5

Schedule for this period:
Machine time

221 (days)

Overhaul and installation

29 (days)

Vacation, Holidays

80 (days)%3

Table 2.

Scheduled machine time and subject of research
in Period VI.

Subject

Hours

Percent

Heavy ion reaction

333

Direct reaction

1094

In -beam spectroscopy

1027

RI production for nuclear spectroscopy

331

Radio chemistry and RI production _300

Radiation chemistry and radiation biology

445

Fields other

Solid state physics

273

than Nucl. Phys.

Heavy ion charge exchange

113

Mossbauer source

128

Track detector

12

Nuclide identification study

74

Heavy ion source study

153

Nucl. Phys.

52.5 %

Particle analyser calibration

9

Beam analyser calibration

45

Alignment of beam handling system

96

Machine inspection and repair

480

Reserved for machine time adjustment

124

Exchange of heavy ion and ordinary ion source

27

RI production for other organizations

243

25.3 %

Accelerator
Phys. and
Maintenanc e.

17.6 %

5307

4.6 %

100 %

4

periodical investigation of various parts, especially change of septum before serious
damage, have resulted in a good operating condition of the cyclotron. Some of the
improvement works done or planned by the group are described in 3-4, 3-5 of thisreport.
Demand for heavy ions is increasing. In addition to the time definitely indicatedin Table 2, about two -thirds of time for in -beam spectroscopy, radiation -chemistry andradiation-biology were used for research by heavy ions. RI production by heavy ions
was also carried out. Production and acceleration of heavier ions than presently used
are studied with the ion source of the cyclotron now used. Results for Ne, Ar, Kr, and
Xe are described in 3-1.
Tritium ion was accelerated up to 24 MeV and several experiments were
performed.

5

3. MACHINE DEVELOPMENT AND ACCELERATOR PHYSICS
3-1.

Production of Multiply-Charged Ions of Ne, Ar, Kr, and Xebythe Electron-Bombarded Hot Cathode

Ion

Source1. Kohno, Y. Miyazawa, T. Tonuma, T. Inoue
A. Shimamura, and S. Nakajima

In the cyclotron, several multiply -charged heavy ions such as C 4 +, N4+, N 5+,
4
0 +, and 0 5+ have been accelerated 1) and their ion beams have been employed in
the study of nuclear and atomic physics, radiation chemistry and biology.
At present, it is planned to accelerate heavier elements in the cyclotron, andfor this purpose the production of multiply-charged ions of Ne, Ar, Kr, and Xe is being
studied by using the electron-bombarded hot cathode type ion source which has beenused for production of C 4 +, N 5+, and 0 5+ ions. 1)
In order to know the kind of ions which were extracted from the ion source andaccelerated in the cyclotron, the m/q spectra of ion beams were measured with a beamprobe fixed at the radius of 55 cm by varying the magnetic field strength froD1 0.5 to
2.0 Wb/m 2 under the conditions of constant oscillator frequency and dee voltage. The
operating condition of the ion source is not changed under variable magnetic fieldstrength from 0.6 to 1. 9 Wb/m 2 . An example of spectrum is shown in Fig. 1. Most of

9

('")

8

-x

"-

7

:;

6

-<-'

~

0

::l...

('")

x

x

«

r"l

5

x

C

Ul

'"

L
L
:::>

u

+

+

+

E

<D

~ «

0
QJ

m

x

3

«

('")

4

('")
('")

~'«

('")

.,.+
«

+

2

Excit in g

Fig. 1.

currentotmagnet(A i

The m/q spectrum of the ion beammeasured at the radius of 55 cm bychanging the magnetic field strength
when Ar gas was fed.

6

multiply-charged heavy ions detected with a beam probe were accelerated by the 3rd
harmonics of acceleration mode in the cyclotron, but some beams were accelerated
by the fundamental mode or the 5th harmonics. The measured intensity of ion beam
which was accelerated by the 3rd harmonics was about 0.5 % of the beam intensity
extracted from the ion source (ion source output).
The measured spectrum when Ar gas was fed in the source is shown in Fig. 2(a).
In the Ar gas several multiply-charged ions of 40 Ar isotope only were observed,3-« 2f~
~
Q)

""-

+

OJ

u

E
0

«
If-

M

Q)

m

_

If)

M

+

+

o

+
"-

«

'-

'III

:

I
3

2

5

4

m / q,nFig. 2(a).

The m/q spectrum of the ion beam
when Ar gas was fed in the source.
f = 6.5 MHz, Vd = 40 kV, arc
power = 450V X SA.
(n) means aharmonic number of radio frequency.

M

<1

c
O

~~

it 300

M

M

'"

M
.r,

C<J

.;,~

'" ~

M

y
V

M

'" M .;,~

'"

,.

"

<J:

'<

-= 200
M

M

E

M

-t ~

en

100

- ~t
::;

~'>-

+

""

~~ ~

JO

Fig. 2(b).

j:

""
M

.l;

""
I

'"

M

If')d;I...... <D1.....

r

M

.

;~

I
3S

40

4 5

The m/q spectrum of the ion beam when Kr
gas was fed in the source.
f = 6.0 MHz,
Vd = 37 kV, arc power = 420V x 7.3A.
(n) means a harmonic number of radio frequency'

7

( b)
"D

10

( a)
Varc

<lJ

Varc

w

>-

~
.......

350V

0
<lJ

0:::

0:::

Va rc

-t-'

400V

+-'
::::>

::::>
0-

.......
::::>

350 '"'"' 600 V

a:;

300V

~
-+-'
0

Varc

10

"D

S

S

0+-'

::::>

0

0

c::

c::
0

0

+

+

(D

~

L

L

<t

Ar gas flow

Ar gas flow

<t

0

0
(kW)

power

Arc

Arc

( d)

( c)

o
~

-0

Vorc
1/

a:;

o

<lJ

400 V
10

10

>-

450 V

"D

~

SOOV

Q)

x

..

Va r c

power

( kW)

450V

0

400V

x

550V

-

>

-+-'
0

1.2ee/ min

1.2ee/ min

•

>

550 V

+-'

0

Q)

350V

//

Q)

0:::

0:::

..:

+-'

::::>

0-

-+-'

::::>

5

0-

0

...-::::>

c::

c::

-+-'

::::>

5

Kr ga s flow

0

0

:~:~

0

~L

;;;L

~

Kr gas flow~

O.See/ min•

O ~----~------~------~------~------~---

Arc

power

0
Arc

(kW)

10

05CC/ ~

Vorc

( e)

power

(kW)

500 ~ 600V

"D
<lJ

Q)

>
-+-'
0
Q)

0:::

-+-'

::::>

Xe ga s flow

0.35ee/ min

50-...::::>
0

c::

.s
+
C>Q)

x
O ~----~------~------~------~------~----

Arc

Fig. 3.

power( kW )

Ar 4 +, Ar 8+, Kr 6 +, Kr 8+, and Xe 9+ ion relative yields vs. are power.

8

because this isotope occupied an abundance of 99.6 %. Several peaks in this spectrum
were assigned to Ar 3+, Ar 4 +, Ar S+, Ar 6+, and Ar 7 + accelerated by the 3rd harmonics ,Ar2+ and Ar4+ accelerated by the Sth harmonics and Ar 8+ normally accelerated.
Among them the intensity of Ar 3+ accelerated by the 3rd harmonics was above SO J.1,A
and that of the most highly charged ions Ar 8+ accelerated normally was about 1 J.1,A.
Fig. 2(b) shows the measured spectrum when Kr gas was fed in the source. In Kr gas
there were many mUltiply -charged ions of six Kr isotopes: 7 8Kr , 80 Kr , 82Kr, 83Kr,
84 Kr , and 86Kr ions. The observed peaks were assigned to Kr 6+, Kr 7 +, Kr 8+, and Kr 9+of the six isotopes accelerated by the 3rd harmonics. Other two peaks with m/q = 4.2
and 4.3 were assigned to 84Kr 4 + and 86 Kr4+ accelerated by the Sth harmonics or to
63 Cu S+ and 6S Cu S+ accelerated by the 3rd harmonics. As these two peaks were
measured also when Xe gas was fed in the source , they are supposed to be due tocopper ions.
The electron bombardment power required to burn the arc discharge was about
SOOW (1.2 kV x 0.4 A) in the cases of Ne, Ar, Kr, and Xe gases as well as in N2 gas.
The source was continuously operated with arc voltage (V arc) of 200 to 650 V andcurrent (I arc) of 2.S to 8 A, and then the arc power (V arc x I arc) was 1.0 to 3.0 kW.
The gas flow rate was different according to the kind of gas. In the case of Xe gas ,the gas flow rate was 0.2 to 0.7 cc /m in, but Ar gas was introduced at the rate of 1. 0 to
3.0 cc/min to keep arc plasma. Intensities of various multiply-charged ion beams
20

15

15

x

u
(])

(])

>

\

\
\
\
\

>-

'0 .

\0

u

\

0
(])

0::

(l)

>(l)

>
0

a'
0::

5

5

0 L-~----~----+-----~----~====~--~4

Ar

Fig. 4(a).

Gas

f low

J L---------~
0.~5----------~1.~0----------~
5(cc / mi n )The Ar 4+, Ar 6 +, and Ar 8+
relative yields vs. Ar gas
flow rate. Eachyield coincides with thevalue at 2 cc/min.
Arc power = 4S0V X SA.

K(

Fig. 4(b).

Gasf l owicc/ mln\

The Kr6+ and Kr 8 +relative yields vs. Kr gas
flow rate. Each yieldcoincides with the value
at 1 cc/min. Arc power= 4S0V X S.SA.

9depended mainly on the gas flow rate and the arc power. Figs. 3(a), (b), (c), (d), and(e) show the variation of yields of Ar 4 +, Ar 8+, Kr 6+, Kr 8+,and Xe 9+ versus thearc power at a constant gas flow rate. All multiply-charged ion yields increase withthe arc power when the arc voltage is 300 to 600 V. Figs. 4(a) and (b) show the yields
of Ar4+, Ar 6+, Ar 8+, Kr 6+ , and Kr 8+ versus the gas flow rate for constant arc voltage
and current for each gas. It is shown that the smaller gas flow brings about the higher
yield of multiply-charged ions. As the multiply -charged ion yields depend on the gas
flow rate more steeply than the arc power and a large arc power brings about a shortlife of source, it is better to operate the source with a smaller gas flow rate rather
than with a larger arc power.
Relative abundance of charge states in Ne, Ar, Kr, and Xe was measured byobserving the ion beams accelerated by the 3rd harmonics. In Table 1 the intensities
of several ion currents extracted from the source are shown, and in Fig. 5 the relative
Table 1

The intensities of ion currents extracted from the source.
(rnA)
Charge state

Arc
ParticleA/

Va (V)Ia (A)

2+

3+

4+

20 Ne

380

5

12

7.5

0.55 0.04

40 Ar

400

4

10

7

Kr

420

7.3

129 Xe

400

7.5

84

5+

1

7+

6+

0.1

0.65 0.26

i

1

0 .1

0 .0 1oiC
NumberFig. 5.

0.11

of

10+

11+

0.04

0.01

0.44
0.15

Ne

E

9+

0.052 0.035

10

<I

8+

II

charges

Ion source output yields of Ne,
Ar, Kr, and Xe charge states.

10abundance of charge states in Ne, Ar, Kr, and Xe is shown. In the case of Ar, therelative abundance of charge states resembles Dubna's data 2) and the intensity of eachcharge state of Ar is almost the same as Argonne's data. 3 ) In the case of Kr and Xe,
the intensities of observed multiply-charged ions decreased to 1/3 or 1/4 when the
charge number is increased by one. The observed highest charge states were Ne 5+,
Ar S+, Kr 9+, and Xe 11 +.

References
1)
2)
3)

Y. Miyazawa and 1. Kohno: Japan. J. Appl. Phys., 9, 532 (1970).
A. S. Pasyuk: Preprint OIY AI, No 7 -3409, Dubna (1967).
G. S. Mavrogenes et al.: IEEE Trans. Nucl. Sci., NS/12, 769 (1965).

11

3-2.

Charge Exchange Experim1ent (3)Cross Sections for Electron Loss and Capture of
Nitrogen Ions in Various Gases

T. Tonuma, F. Yoshida, 1. Kohno,
Y. Miyazawa, T. Karasawa, T. Takahashi, and S. Konno
N4+ ions at energies of 65, 82, and 95 MeV were made to pass through H2, He ,N2, Ne, Ar, Kr, and Xe gases, and the cross sections for electron loss and capture of
the nitrogen ions were measured, the llleasurements being carried out essentiallyby the same method as had been reported. 1) The experimental apparatus and procedure
were also the same as in the previous report except that the collision chamber wasplaced in a large vacuum chamber in which the pressure was made variable from1 X 10-3 to 8 x 10-1 Torr by replacing 4¢ x 20 channels to 3¢ x 20 as shown in Fig. 1.
Quadru pole magnet//'/r!,
Beam shutter
II
/

//
/

/ /',,__
I I
- -,
I I
I

<, II

-"

-I I,

\

I"

J

t

Pressure Co llision chamber
gaugttGas- t j - - f - - - - ,Li'7----- ~i~ r V50CL::

J

Analyzing magnet

Fig. 1.

L

l

'

\\

'----_ _ __=Beamr------

Z Y:::Jt

To pump(6 " DP 1

j

l

[
t

r

"

To pump (6 DP 1

Channels (3¢X20l

Diagram of apparatus.

(1)

Cross sections for electron loss and capture of nitrogen ions
The relative amounts Fk (k = 4, 5, 6, 7) of N4+, N 5+, N 6 +, and N 7 + ions wereobserved when N 4+ ions of energies mentioned above passed through the gases. F 400

and F5 00 , that is, the amounts of N4+ and N5+ states for a medium thick enough to reachequilibrium can be assumed to be zero and, therefore, the cross sections of 054' 064'
° 65, °74, and 075 are negligible. Thus, the charge composition of ion beam is expressed by the following equations:dF 4 / ddF 5 / dn=- (045 + 046 + 047)

0

0

°45

- (056 + °57)

0

o

F5
( 1)

dF 6/dn

046

°56

- °67

dF 7 / dn

°47

°57

°67

The solutions of Fk are written as
( 2)
( 3)

12

(4)

( 5)

where 7!: is the number of gas atoms in a volume with 1 cm 2 cross section along theion path and

The equilibrium states of F 6 and F 7 give the following relations:
F 6=

076

F 7=

067

- - = --and F600+ F 7= = 1.

The cross sections were obtained by the least-square fit of the calculated F k in
the above to the measured F k' Firstly, cross sections of a 11 were obtained fromthe measured F 4 and Eqn. (2). Secondly, a 2l and a 22 were determined from themeasured F 5' Eqn. (3) and a 11 already known. Finally, the measured F 6' F 6 = andF7=' Eqn. (4) and all' a2l' a22 (already known) determined the cross sections or a31,
a 32 and a 33 . Cross sections obtained by this procedure were 045' 046' 047' 056' 057'
067' and 076 of nitrogen ions. The calculations were carried out with the DDP 124
computer in this laboratory.
Fig. 2 shows the relation between charge distribution and gas target thickness
when 95 MeV N4 + ions traversed krypton gas. The solid points are values of measured
Fk and solid lines show the calculated Fk using the cross sections determined by
the above procedure. In H2 and He media only 045 was measured because the pressurein the apparatus could not be increased to the value necessary to attain the equlibrium
states Fk for those media since cross sections are smaller in these gases.

13

1 . 0 . - - - - - - - - - - - -- -- - - - - - - .
0.9

o.s

0.6

0.3 TorroFig. 2.

(2)

0.1

0.2

0.3

0.4 X 10\8 otoms/cm2

Charge distribution vs. target thickness of krypton gas for 95 MeV N 4+
ions. Solid lines are the calculated
charge distributions using a 45=50.9,
a 46=10.0, a 47=0.7, a 56=23.0, a57=6.2,
a 67=13.7 and a 76 =1. 9 in unit of 10 - 18
c m 2 / a tom.

The relation of cross sections to the atomic number Zmed of the medium

Fig. 3 shows the dependence of cross sections for single electron loss of a 45'
a56' and a67' and for single electron capture a76 on the atomic number Zmed of thegases, the energies of nitrogen ions being 65, 82, and 95 MeV. The cross section a45
is nearly proportional to Zmed2 up to Zmed ~ 10 and to Zmed2/3 approxilnately for
the Zmed values larger than 10. The behavior is the same with the dependence ofthe cross section a45 of carbon ions on Zmed. 2 ) Th e Zmed2/3 effect follows froma shielding effect of atoms of a heavy medium. Since dependence of cross sections
ai' i + 1 on Zmed for ions of lower energies are affected by the shielding effect andthe deformation of the atoms of the medium, 3) it is complicated to be treated theoretically. In the energy region of the pres ent work, however, 0 nly the shielding effectapproximated by the Thomas -Fermi model can explain the dependence of cross sections
ai' i + 1 on Zmed' Fig. 4 shows the cOlnparison of the cross sections a45' aS6 and (J67
of 65 and 95 MeV nitrogen ions with the theoretical values derived by Bohr4J and
Dmitriev. 3 ) In the figure (Ji' i + 1 (solid lines) up to Zmed ~ 10 are given by the formulain the free collision approximation without taking the shielding into account and for the14I

565MeV
82 //

95 "
E

10-17

0

+-'

0

N'E

!//

5

u

/

c:
0
+-'

U
Q)
if)

~/

if)
if)

0

L

u

I

//

/

/

I

-

I

/

I

/

/

f /

r

/

// j _-t

/ /
/ /
I / -

I

10-18

/

1/
'I

.A

I

1/
1:

/

1

/f

/

-

- -----1....
/ / I/

I/////!

I

I /

/

I

I I

/ I

I I

f/
I

f'

0-19~1L--~1--_---:!;1 ;--:-l:1;::----;~1:;----;:;~
l--;:f_;;_1--:::;-----,

1

1

Fig. 3.

2

7 10

18

36 54 Z med

The relation of the cross sections, (J 45' 56 , and (J67' forsingle electron loss and 076 forsingle electron capture on theatomic number Zmed of themedium.

°Zmed larger than 10 by the formula derived in the strongly shielded field of an atom.
Dmitriev defines that electrons are lost mainly from the outermost shells in the ions(see Ref. 3». Therefore, one electron in L-shell of nitrogen ions should be lost in thecase of 045' But the values of (J45 shown in Fig. 4 are calculated on the assumption of
two electrons being lost because the cross section of 0 6' which loses two electrons
4simultaneously, has a finite value.
The relation of (J 46' 047' and 057 for multiple electron loss to Zmed could not beestablished because the observed cross sections involved large experimental! uncertainties. The ratios of them to single loss are approximately 0
46 /045 = 0.1 ---.. , 0.3,
047 / 045 = 0.01"-' 0.06 and (J 57/056 = 0.1"-' 0.3 for Zmed of from 10 up to 54 and theseratios increase with Zmed'
The cross section 0 76 for single electron capture is proportional to Zmed "-'Zmed3/2 and has the same dependence as 065 of carbon ions. 2)

15

5- -e--65MeV--- -- 95
/I

0""67

c

o

(j)
(j)

::
u
1 0- I S I--LJf--+-_-+~~-+---+------------i

5

18

36

54

Z med

Fig. 4.

The comparison of the crosssections, (J45' (J56' and (567'measured for 65 and 95 MeV
N4+ ions with the theoreticalvalues (solid lines) calculatedwith Bohr's and Dmitriev's
formulas. Upper line for 65
MeV and lower line for 95 MeV.

References
1)

T. Tonuma, Y. Miyazawa, T. Karasawa, and 1. Kohno: Japan. J. Appl. Phys. ,2., 1306 (1970).
2)
3)
4)

T. Tonuma, Y. Miyazawa, T. Karasawa, 1. Kohno, T. Takahashi, and S. Konno:
IPCR Cyclotron Progr. Rep.,.!, 15 (1970).
1. S. Dmitriev, V.S. Nikolaev, L. N. Fateeva , a nd Va. A. Teplova: Sov. Phys.
JETP. , ~ , 11 (1962).
N. Bo hr: K. Danske Vidensk, Selsk. mat. -fys. Medd., 18, No.8 (1948).

16

3-3.

Acceleration of Tritium

Ions and Measurements ofResidual Tritiumin the Cyclotron

I. Kohno, A. Shimamura, 1. Sakanloto,T. Tonuma, and T. Hamada(1)

Triton acceleration

Preliminary triton accelerations using 1 and 100 Ci tritium gas, respectively,
were carried out in the preceding period in order to obtain technical experiences. 1)
In this period a regular triton acceleration has been made for successive five days.
Procedures of the experiment and measurements on residual tritium in the cyclotron
and equipments involved were the same as in previous runs.
A mixture of 500 cc atm of deuterium gas and 40 cc atm (100 Ci) of tritium gas
was prepared and supplied to the circulation systenl at a time. The ion source, whichusually needs a gas flow of about 50 Ius, was thus provided with a tritium gas flow ofabout 3.7 Ius (44 Ci/h). The acceleration was continued for 15 ----- 25 h with one supply of
the gas ~ixture to the system. The time of duration depended on the arnount of leakageof air to 'the acceleration chamber, the circulation system and the beanl handling system.
In the present run a leakage of less than 0.5 Ius was found at the target chamber.
When the beam intensity decreased considerably due to leakage of air as well as
outgasing, a charcoal trap through which the gas was circulated at roonl temperature
was cooled by liquid nitrogen for adsorption of all gases, and it was replaced by a newone. Then , another batch of the gas mixture containing 100 Ci of tritium was introduced
to the system and the next acceleration run was started. 700 Ci in total of tritium gas
was used through the whole runs.
At the end of each run, the remaining tritium was collected in the charcoal trap
and another liquid nitrogen trap made of glass, then they were disconnected fromthe system and hydrogen gas was introduced and circulated for "washing" the systeln.
In the whole runs about 2 cc of water was condensed in the glass trap. These traps,
filaments and cones of the ion source and pump oils were disposed of as radioactive
wastes.
Intensities of deflected and analysed triton beams are 10 jJ.A and 100 nA, res'p ecti vely.

(2)

Measurements of residual tritium

From the preliminary tests, it was known that there may be a possibility ofa strong contanlination of vacuum pump oil with tritium, and, therefore, oil samples
from pumps were measured using the liquid scintillation counter. A concentration ofas much as 960 jJ.Ci/cc was detected in the oil of circulation pump and main diffusion
pump of the cyclotron.
Air samples taken from different places around the lnachine after machine
shutdown were measured various times with ionization chalnbers of collection type,and moisture in the air was also collected in a liquid nitrogen trap, and water samples
thus obtained were measured with the liquid scintillation counter. As the results ofboth measurements nearly coincided, it may be said that the tritium remains as a fonnof water. Results of the measurements are summarized in Table 1.

***

**

*

Release ofresidualtritium

(

2

122 d
173 d
191 d
191 d

Apr. 27***

Jun 17***

JuI. 5

JuI. 5***

Aug. 16

8 X 10-

5 X 1~-6

5

250 d
250 d
270 d
270 d

Sept. 14

Sept. 14****Oct. 4Oct. 4 * ****

4 h

40 min"After 1 h washing with fresh air.

1 X 10- 5

3 X 10-3 X 10- 5231 dAug. 16***4

4

1 X )0- 5

2 X 10-1 X 10- 5

3
1 x 10-231 d

6 X 10-2 X 10- 5

1 X 10- 5
9 X 10- 3

6XI0- 5

9 X I0- 5

5

6 X 10- 5
3
4 X 10-9 x 10-

7 X 10- 5

3 X 10- 5

****
*****

1 X 10- 3

76 dMar. 12 **2 X I0- 3
4 X 10- 5

75 dMar. 11

4 X 10- 3

1 X 10- 4

3 X 10- 4

66 dMar. 2 **6 X 10- 5

6 X 10- 3

4 x 10- 3

65 d

10- 3

Mar. 1

10- 3

Resonating
tank

10- 5

10- 4

Accelerationchamber

15 d

10- 4

10- 4

10- 4

Ion source

Jan. 10, '71

10- 2 ______ 10- 4

Blowerexhaust

10- 4

10- 5

Circulation
system

10- 4

10- 5

Control roomhTime afterend of run

Dec. ·26, '70

During loadingor recoveryof tritium* :During acceleration

Time ofsampling

Tritium concentration (in f.lCijcc) in air during and after triton acceleration.

Tritium leaked from an imperfect connection of exhaust pipe.
After 20 h washing with fresh air.

Tritium leak

Contamination
due to:Table 1.

.....
-...J

18

It is seen from the table that, even in 9 months after the triton acceleration,
3
a concentration of 10- jlCi/cc of tritium has been detected in the air inside the acceleration chamber just after the exposure of the chamber to the atmosphere for overhaul.
The concentration was, however, reduced to 10--4 ~ 10-5 MCi/cc by means of a compulsive blowing of fresh air to the chamber. The "blowing off" of the chamber was
carried out by a roughing pump (1500 /min) and a mechanical booster pump, but atpresent they are replaced by a large blower having a capacity of 10 m 3 /min. Though
the level of tritium contamination is gradually decreasing, this procedure is stillnecessary before working in the chamber during overhaul to keep the concentration
down to the maximum permissible limit.
A contamination of O. 5 ~ 0.9 !.Lei/cm 2 of tritium was detected using the smear
testing method on the inner surface of the chamber and it remained for two m~ onths.
It may be due to the deep permeation of tritium to metal surfaces.

e(3)Discussion

It is a remarkable fact that air blowing is much more effective to the reductionof tritium concentration than keeping the chamber in vacuum of 2 X 10-D mmHg fora long time.
A simulation experiment will be done for investigating the behavior of tritium
atoms adsorbed on rnetal surfaces.

Reference
1)

1. Kohno et al.: IPCR Cyclotron Progr. Rep., i: 11 (1970).

19

3-4.

Design of the Power Supply Distributor for the Beam
Handling System of Cyclotron

H. Nakajima and M. Hemmi

The analyzing and focusing system of the extracted beam is composed of sevencourses, and now seventeen magnets are installed and operated. These magnets withthe suitable combination of polarities and exciting currents achieve beam transport tovarious target areas. Fig. I shows the analyzing and focusing system of the cyclotron.
The directions for use of the magnets are not firmly established. Moreover,a pair of power supplies excites several quadrupole-pairs in turn and must be switchedon to alternative pairs according to the course used. These situations 11lake the operation of the beam transport system complicated causing operation mistake and machine
trouble. Therefore, a central controlling system has been desired and planned in thelast few years.

SMALL
EXPERIMEN TAL
AREA('DO/,

S!"

LARGE

QIO
----2.112 Co
Mag,-..!!l.:§t __Baffl

EXP ERIME~TAL

AREA

CYCLOTRO
ROOM

Gate - box with pn e umati cbeam s hutt e r'
Bea m bunch se lec tor

Qo-; Mag

Baff le\IPCRCYCLOT RO)l\

Shie Id i ng

Shieldingwall~'~'~1--:!::2'--:!:-3'-4~'--!'
0.5 1 5 m

wallI

Fig. 1.

Analyzing and focusing system of the cyclotron.

The distributor
The system has two functions; one is the selection of combination of magnets andpower supplies, and the other is indication of the state of operation. The indication is
given by a graphical display device in the control room, and the selection and control ofmain system in the cyclotron power room is made by switches on the display panel
remotely. Block diagram of the system is shown in Fig. 2.

20J)i sp Jal
s i gnmagne t s

: excep t

Fig. 2.

(a)l/ - pa i t's f

Block diagram of the distributor. Block
diagram is illustrated for a typicalQ -pair.

Selection of the combination of Q -magnets and power supplies

The selection is to be made among the Q-magnet assembly only. Each of the BA,
SW I, SW II, DS,and BE magnets of Fig. 1, has an exclusive power supply. Therefore,
no change of power supply is necessary. The selection system is capable of connecting
15 Q -pairs and 10 power supply pairs in maximum. A Q -pair can be connected withthree emergency power supplies as well as be used alone normally. One special pair of
power supply can be connected with any of the Q-pairs if necessary. Possible combination of Q -pair and power supply is determined by estimating the probability of troubles
for each course and for operaUng frequency. Control units are standardized and areshown in Fig. 3 with their circuit schematics.
They have solid state discriminating safety circuits with logical levels that protect
the connection system from operation mistake and other troubles such as change ofcombination of live magnet and power supply. Further, memory of the state of operation
at the time of emergency shut -down can be preserved.

••0
0 . 0 •••
0

Q-3

3

I2

5

Fig. 3.

I9 I

(a)

Q
5

5

6
9

•

0 . 0

•
0

•••
0

Control units.

21-- --- lr - ---- - - --- ~- -

SU- 1

I

Se lec tion unit

I

I

I

I

~~~
, --~~--~~~~~~:~~+----+~~

: :

~~~~

H - - - -- - ,

:

I

:

:

I

I

.--DI-~~~"': ---t-1-t-+~ .....,--H~~-l-r1
I

I

I

I
I

I

I
I
,

I
I

~-T-;'1-<>' ---t-1-t-+~ .....r--tDt--~--L.-rI

:
I
I

I

I
I
I

I

I

I

~~~--1-~""'~~~~,

II~~ - -----I--~
I
I

I
,

I

:II"'-', ~
I
I

NO M

I

:
:

','

Y- 2

__

I
I

PO L.l

I

REV

NOM

I

POL.2

REV

~

~Y-4

i

- - --,

:

uifE

MY- 2

~

Fig. 3. (b) Schematic circuit of the control unit.
(b)

Indication of the operation

A 2 m X 1. 2 m panel displays the operating polarities of magnets and the state ofbeam transport graphically . In the Q-pair assembly, the operating unit indicates theconnected power supply number and operating polarity of each magnet as well. The
polarity is represented by a line on the panel denoting the motion of ion beam in thehorizontal plane; convergence or divergence. The operating power supplies are also
indicated with its numbers at the bottom of the graphical panel.
In the BE magnet, its polarity is indicated by the bending direction of ion beam.
For the SW I, SW II, BA , and DS magnets, the graphical display shows thetransporting direction of beam. Fig. 4 shows the designed panel of graph.

!

(Jpe ,·. ti un

0 1 2 3 4 5 6 7 8 9Fig. 4.

Graphic display panel.

-

'-

I

1
I

22

3-5.

Safety Devices of the Beam Handling System to Prevent
Radiation Hazard and Vacuum Trouble

M. Hemmi and H. Nakajima

There are seven beam courses in the extracted beam handling system of thecyclotron by which the beams are led to each target position. General layout of thebeam handling system and safety devices can be seen in Fig. 1. The safety devices
were designed and attached to the beam handling system to protect persons fromradiation hazard and to the vacuum system from mis -operation or any other accident.
Some are already in use and others are being installed. They will be described briefly.

Sma ll experimen tal area

Vaccum isolation valve
Beam stopper

Large experimentalarea®

Oil diffusion Pump unit~

Mechanical booster
pump unit

PA - - ---f

Cyc loFig.!.

(1)

Layout of the beam handling system and safety devices.

Radiation hazard protection

Frequently, persons have to enter one experimental area when the cyclotron isbombarding the targets in the cyclotron vault or sending a beam to another area.
The beams must not be led to a place where any person is working in case ofmis -operation or trouble of beam adjusting magnets.
Such is the aim of this device. It should also protect the surface of a vacuum
valve from bombardment when it was shut off to isolate the beam pipe of the experimental area from the main vacuun1 .
The procedures of opera tion can be seen in Fig. 2. Signals indicating the state ofdoors of each area are given to a mixing and discriminating circuit and a distinction
signal is fed to a beam stopp er control circuit at a suitable location. The stoppers are
set in the cyclotron vault and shut off the beams there from going downstream further.
Stopper control signals are also given by the position of the vacuum isolation
valve, so that the stopper is always "in" when the valve is not opened. The beam
stopper is a water -cooled graphite plate to 111inimize residual act~vity and is actuatedby a pneumatic cylinder. The vacuum seal and bearing of the n1ain shaft are made ofglass wool and TEFLON containing mo1ybdenum-disulphide.

23

open

shut

d2,

d2,

1st course ofbeam sto pper
control

Exper imen t al area door

2 nd course ofbeom stop percont r ol

Ex perimenta I ar ea door

3

4

II

5

/I

II

6

1/

II

7

/1

II

course ofvacuum isolation
va lve7

1st,,5 hut "

4

5
6
7

Fig. 2.

1/

Block diagram of the beam stopper system.

This structure is reliable in operation and any maintenance work is hardly
necessary.
(2)
Vacuum system protection
The vacuum system of the cyclotron and the beam handling systern are desirable
to be protected against vacuum failure at the end of each beam pipe where accidental
leakage and breaking of foil of experimental apparatus are most likely to occur.
The systems must not also be left unguarded against unexpected failure of power
supply. The protection divice is twofold. One is fast isolation of the beam pipe if
failure has occurred, and the other is protection of the pumping system and automatic
control of each evacuation stage.
(i)
The isolation valves can be opened only under the condition of "goodvacuum" of the corresponding branch of pipe and main volume of the beam system.
"Good" condition is determined by two methods according to the desired vacuum
pressure.
One uses Pirani detectors and gives trip signals at about 50/lHg. It is called highlevel unit. The other is a Penning ionization gauge to give an alarm at the threshold
which can be arbitrarily set between 10-4 and 10-3 mmHg. It is called low level unit .
A detector of the latter type is known to give a "good" reading when it is at the atmospheric pressure. A method to prevent this error is provided.
The device works always towards the safer side in case of accidents such as
breaking or grounding of detector lead and failure of power supply.
It is standardized in the modular form and can be used in any place with an aim
other than valve control. Analog output is also provided to give the vacuum pressure.
(ii)
A vacuum unit is made up from rotary, mechanical booster and or oil
diffusion pumps. Each has a region of pressure where it works properly. Many units
are in use with the beam handling system and the cyclotron. Automatic control of thesepumping systems seems necessary in view of need of simultaneous control of themtaking into account of the vacuum condition at each site especially in case of emergency

24such as unexpected power supply cut-off. Fig. 3 shows a standard evacuation set andFig. 4 is the block diagram of automatic operation and protection. Given the criterion
for each stage, the evacuation process proceeds automatically step by step evaluating
the condition at each stage. When vacuum failure or power cut -off had coccured thepump system would not necessarily go back to the initial stage and the operation would
be able to resume from a stage suitable for the vacuum condition of the volume to be
evacua ted again. Manua 1 opera tion is of course possible. Standardiza tion of an evacuation set to improve interchangeability is being planned.
The vacuum failure detection and control system is the same as that used for
isolation valve operation and there is two kind of detectors according to the vacuum
pressure range concerned as stated above.
Beam pipe(4" )Quarter sWing butterfly valve
Go uge 1, gouge 2
T hermo - e lect r ic (Pel tie r ) baffle ( Water -c ooled)
Water - cooled baffle

Fig. 3.

Schematic view of evercuation set.

Cooling Yes
water

Power
Yes

Go

~

R. P
Cooling
On, Ott

Butte r tly
valveOpen, ShutDP
Baff leOn,Off

BuHerfly valve
operation
Open Shu t II----10.' 10- 'Fig. 4.

II

5X10·' 10-'___ _Block diagram of automatic operation and protection,

25

3-6.

Improvement of the Beam-Handling System
for Experiments of Nuclear Physics

T. Wada, T. Fujisawa, and S. Motonaga

Two beam courses 1) have been used for the experiments of nuclear scattering
until the completion of the PA system. 2) Because the energy analyzed beam cannot be
used for other expe:r:iments after the completion of the PA system, a new deflecting
magnet (SW -II) was installed in place of CL magnet. By means of this magnet theenergy analyzed beam can be deflected in two directions. One is to the PA magnet andthe other to the scattering chamber for SSD and particle'- gamma experiments. The

476 .3

~
('f)
t!)

~

C

491.8

/
~ --

~
C\J
C\J

N

('f)

~

646 . 0Fig. 1.

Shape of the magnetic pole.

floor

2050

Fig. 2.

('f)t!)

Foundation of the SW -II magnet.

B

26

shape of the magnetic pole was designed by a computer to minimize its area. The
results are shown in Figs. 1,2, and Table 1. Fig. 3 is the excitation curve. Fig. 4
shows the beam -handling system around the new magnet. The beam optics for eachcourse was calculated and shown in Fig. 5.

Table 1.

Characteristics of the SW - II magnet.

Type

H-typePole gap

40 mm
0Maximum field
Radius035 , 40 , 75°

Deflection angle

12 kg

A-C

2132 mm

A-D

935 mm

B-D

1860 mm

Weight total

17.8 tCost$36,000

Maker

Tohoku Metal
Industries, Ltd.

12

\0

-

~ 8

5

4

Magnet cu rr ent

Fig. 3.

(A)

Excitation curve.

27

Large exper imenta l area
Shieldi ng wall

slit

Fig. 4.

Beam -handling system around the SW -II magnet.

SW-ll

Q-magnet

Slit

SSD

s.c.

D

M.=0.6
Mz =-1.0

SW-ll

Q -magnet

Slit

PA S.C .

M"-0 . 2
Mz=-O 5S.

'.2
Mz =13

Mz=-3.3o84Distance

Fig. 5.

10

12

(m)

Beam optics of each course.

References
1)
2)

S. Motonaga, H. Kamitsubo, M. Hemmi, N. Nakanishi, and K. Matsuda: lPCR
Cyclotron Progr. Rep., 1, 10 (1967).
N. Nakanishi and K. Matsuda: Nucl. lnstr. and Methods, 57, 245 (1967).

28

4. NUCLEAR PHYSICS
Scattering and Reactions

4- 1.

27 A 1 ( 12 C, 11 B) 28Si and 27 A 1 (12C, 13N) 26Mg Reactions
S. Nakajima, 1. Kohno, T. Tonuma,
and M. Odera

In order to study the reaction mechanism of one-nucleon transfer induced byheavy ions, the differential cross sections of 27 Al (12C, lIB) 28 Si and 27 Al ( 12C, 13N)
26 Mg have been measured with a j E-E counter telescope and a two-dimensional pulse
height analyzer.
The 12C beam extracted from the cyclotron was led into a 100 cm scatteringchamber and focused in a size of 1. 5 mm X 4 mm on a target. The energy resolution of
the beam was about 0.5 %and the intensity was 30 nA "-' 100 nA. Thickness of the 27 Al
target was 380 J.1g/cm 2 . Combination of 15 J.1m and 200 11m surface barrier Si detector
was used for the counter telescope. The electronic circuit of the detection system wasdescribed previously. 1)

27Al ( 12 C , "8) 28Si

- 1 772 MeV

93.8 MeV

90 .8 MeV

908 MeV

702 MeV1040Fig. 1.

Angular dis tributions of thereaction 27 Al ( 12 C, lIB) 28Si.
The reaction products, lIB and
28Si, are both in their groundstates.

40

Fig. 2.

Angular dis tributions of thereaction 27 A I ( 12 C 1 lIB) 28S i
leading to excited state of 28 Si(1. 772MeV)

29

27Al + 12 C ELAS TI C SCAITERING

27Al ( 12 C ,13 N )2 6 Mg

Groun d stat e

E( 12 C) = 702 '!leVV= 5 85 MeV
W=16 0 MeV(r =1 .24 trn([ = 1.45 "Or= 0 .7 1 "0 1= 0 .86 ".
1. 12 "

0.1 -

"'--.

".~.

0.1

0 .01

40

Fig. 3.

Angular distributions of thereaction 27 Al (12C, 13N126Mg.
The reaction products, 3 N and
26Mg, are both in their groundstates.

793Me:·~
V=55.0 MeV
W= 17. 7 Me V
rr= 1.24 tIT'r[ =1. 43"
0r= 0 .64 "0, =0 .72"
rc= 1. 11"

•

•

30

Fig. 4.

.-.~40

Angular distributions of theelastic scattering of 12C on
27Al a t the energies of 70.2 and79.3 MeV and an example of
optical model calculations ofthem.

Effects of variation of incident energy on the angular pattern were investigatedby changing the 12C energy at 70.2,79.3, 90.8, and 93.8 MeV. These energies are
all far above the Coulomb barrier of entrance and exit channels and the angular distributions obtained (Fig. 1, Fig. 2, and Fig. 3) show invariably a diffraction-like patternwhich differs from one-peak feature at lower energies. Phases and absolute values ofthe pattern vary smoothly with energy. Any drastic change was not observed in thisenergy region. Comparing the cross section of lIB to that of 13N , it is indicated thatthe transfer of a proton from a target to a prOjectile is less favored than the transfer
in the opposite direction as mentioned in the other case. 2) 3) The data analyses by
DWBA calculations are now under consideration.
Knowledge of the optical-model wave functions for the relative motion of thecomplex nuclei is necessary to describe transfer reactions in the DWBA. Angular
distributions of the elastic scattering of 27 Al ( 12 C, 12C) 27 Al have also been obtained.
They resemble fairly well in shape with those of 28 Si + 12C and 27 Al + 14N at about
the same energy.4) Optical parameter fits are being investigated with the "SEARCH"
code written by T. Wada. 5) Fig. 4 shows the angular distributions at incident energies
of 70.2, and 79.3 MeV and an example of parameter fits to them.

30

References
1)

S. Nakajima, 1. Kohno, T. Tonuma, and M. Odera: IPCR Cyclotron Progr. Rep.,~ 35 (1970).

2)
3)
4)
5)

R. M. Diamond, A. M. Poskanzer, F. S. Stephens, W. ]. Swiatecki, and D. Ward:
Phys. Rev. Letters, 20, 802 (1968).
J. Galin, B. Gatty, M. Lefort, J. Peter, X. Tarrags, and R. Basile: Phys. Rev.,
182, 1267 (1969).
1. Kohno, S. Nakajima, T. Tonuma, and M. Odera: ]. Phys. Soc. Japan, 30, 910(1971),
T. Wada: IPCR Cyclotron Progr. Rep., 2, 87 (1968).

31

4-2.

The 100, 98Mo (t, p) 102, 100Mo Reactions and Low- Lying 0 + Statesin Even Molybdenum Isotopes

K. Matsuda, S. Takeda, N. Nakanishi, 1. Kohno,
Y. Awaya, S. Yamaji, and S. Kusuno

A low-lying 0+ state at 736 keY of 98Mo has been found experimentally by the EO
transition,l) the 97 Mo (d,p) 98 Mo reaction 2 ) and the 100 Mo (p,t) 98 Mo reaction. 3) In
the experiment of inelastic scattering of protons on the 98Mo target,4) this 0+ state has
been unable to find because of its small cross section compared with that of a close 2+
state. On the contrary, the large cross section leading to the 0+ state makes the 2+state undetectable in the 100Mo (p,t) 98 Mo reaction. 3) The inelastic scattering of protons by 100Mo also reveals a level at 700 keY being 0+ stat.e. 4 )Although the ground states of 98 Mo and 100Mo appear to be describable underconsideration of a simple shell-model by closed 2dS/2 and 3s 1/2 neutron subshells
respectively, configuration-mixing of neutron shells will play an important role not onlyin the ground states but also in the excited 0+ states because of 2d3/2, Ig7/2 and Ih 11/2
neutron orbits lying fairly close to those shells. Cheifetz et al. provided experimental,.

......,

858 :!: 20keV

.\
•

\/--\

10- 1

grd.

0+

I.
309 ::t::20keV\:2; 10-1
E

c:::
"0

~

L

~

~ 10-2
'i3

!-!-"

"b

"0

134 1:!:20keV

-

"b

'"

\

"0

!!
"-(~/

1898 ! 20keV
714 ::t::20 keV

c

o
SC M

Fig. 1.

Angular distributions for the transitions leading to the first six
states seen in the reaction 100Mo (t,p) l02 Mo . The solid curves
are drawn through the experimental data points as a gUide to the eye.

32

evidence as a new deformed region near A ------ 100. 5) According to their work, the deformed region will begin from I02Mo for the molybdenum isotopes. The investigationof the low-lying states of 102 Mo and 100Mo will then give some useful information on
the study of nuclear structure of molybdenum isotopes in connection with other experimental results. Measurements of differential cross sections of the 100Mo (t,p) 102 Mo
and 98 Mo (t,p) 100 Mo reactions have been done under these backgrounds.
The experimental technique has been described elsewhere.-6 ) A triton bean1 of
15.8 MeV from the cyclotron was used in the experimentsJ) Angular distributions ofemitted protons were obtained with a J E-E counter-telescope having semiconductor
detectors. * Six peaks were observed corresponding to the low-lying states of 102 Mo ,that is, 0,309,714,858, 1341, and 1898 keY excitations. The uncertainty in the Q values
is ±20 keY due to the energy resolution. The angular distributions for these levels areshown in Fig. 1. The ground and 714 keY states are strongly excited, showing the san1e
angular distribution pattern. These angular distributions are also similar to those of
L=O transition of (t,p) reactions in this mass region and energy ranges. Then, theexcited 0+ state at about 700 keY is also found in 102 Mo nucleus. Figure 2 shows
the low -lying states of molybdenum isotoRes for comparison. It is of interest that noexcited 0+ states are observed in 92, 94, 96 Mo in contrast with the 0+ states at about
700 keY in 98, 100, 102 Mo . Blair et al. have reported that several 0+ states above
the ground state were observed in 92 , 94, 96 Zr , though there is no 0+ state observed up
to an excitation energy of 3.2 MeV in 98 Zr .l0) Since the neutron numbers of 100 Mo are
equal to ths>se of 98Z r, the low -lying states excited by (t,p) reaction are expected to be
in resemblance between them. Figure 3, however, shows very different spectrum
except for the level positions of 3- states. This difference in the low -lying states is
to be ascribed to the two -proton addition. The differential cross sections of 0+ statesin 100 Mo and 102 Mo observed at 350 are as follows:
grd. (O~---------440-f-.t b / stfor 100Mo,r.}

700 keY (0+)----------- - (5- )

3 = ~:_ _ _ 6+
- -T

_ _ _ 2+- - - 4+_ _ 4+- - 2+

= ~:

- -2+

_ _ 2+- - 0+

- -0+

- -0+

- - 0+

- -0+

94

96

98

( 0 l ,( e l,(e! 1( 0 l,(el,(e! 1- - 2'~- - 2+

0- -15-)- - - 5- - - T- - - 4+ - - 6'2~80-llb/str.

- - 0'

92- - 6+

- -T

- -T
4+
2'

- -3- -14+ )- -6'- - 6+- - 4+- - 4+- -0+- - 2+- - 0'- - 2+
- -0+

100

102

104

106

( bl,(el ,(el

(e 1

(il

(f 1

=

- - 0+- -r- -12+)- - 0- - 2+

A~

Refs . (o l,(c l,(e! l(bl,(e l,(e! 1
(g)

(a)
(b)
(c)
(d)

(p,p ') experiment, Ref. 8).
(p,p') experiment, Ref. 4).
(a,a') experiment, Ref. 9).
(p, t) experiment, Ref. 3).
Fig. 2.

*

(e)
(f)

(g)

(t,p) experiment, present results,
fission fragment, Re f. 5).
r transition, Ref. 1).

Level schemes of even molybdenum isotopes.

Surface barrier detectors obtained from ORTEC INC.

33

2

=

3-

- - 2+- - 2+~1- - 0+
98Z r

0- - 3- -4+- - 2+- - 0+- - 2+--T- - (4+)_ _ (2+)- - 0+- -0+- - 2+- - 0+

,ooMa

I02Ma

Z

40

42

42

N

58

58

40

(]PCR)(lPCRI(LASLlFig. 3.

grd. (0+)

1l 11

L e vel schemes of 98Z r
100Mo and 102Mo.
'
340-j.lb/str.

714 keY (0+)

160-j.lb/str.

}

for 102 Mo .

In order to investigate the sensitivity of the transinon strengths to the mixing ofconfiguration, DWBA calculations are performed including 2d 5 / 2 , 2d 3 / 2 , 3s 1/2' Ig7/2'
1hll/2' 2f7/2' and 1h9/2 neutron shells. The form factors for the DWBA calculations
are obtained by the harmonic oscillator wave function joining smoothly with a tail of thecorrect decaying wave function, the Hankel function. The QRPA (quasi -particle random
phase approximation) was used for the calculation of phonon states. The optical potential
parameters used in the distorted wave calculation are given in Table 1. Preliminary
results of the DWBA analyses for the ground (0+), 309 keY (2~ and 1859 keY (3) states
are shown in Fig. 4. They give quite good fitting for the experimental results. Any
good fits for the experimental angular distributions of 858 keY and 1341 keY states,
however, cannot be obtained from the present calculations of the form factors.
Since there is a close resemblance in the experimental angular distributions
between the 309 keY and 858 keY states, the spin-parity of the 858 keY state may be
assigned to 2+. The angular distribution of the 1341 keY state has no resemblance tothe other ones. Considering the systematics of the level schemes of 98 Mo and 100Mo,
the 858 keY and 1341 keY states of 102Mo may be assigned to 2+ and 4+, respectively.
On the one hand, however, the 1080 keY (2~ and 1150 keY (4~ states of 100Mo excitedby inelastic scattering of protons 4) could not be found by any observable cross sectionin the present (t,p) reaction, but the 858 keY and 1341 keY states of 102Mo were excitedby the (t ,p) reaction as show in Fig. 1. Considering this behavior and the differencesin the cross sections leadin to the 0+ states, a nuclear structure of 102Mo may besomewhat different from 10 Mo.

5

Table 1.

Optical parameters calculated with an automaticparameter search computer code "SEARCH" 1).

V
(MeV)

ro
(F)

ao
(F)

W
(MeV)

r'1
(F)

ai

rc

(F)

(F)

Triton

173.5

1.22

0.730

30.45a

1.22

0.868

1.2"5

Proton

49.3

1.27

0.825

20.3

1.32

0.468

1.25

a

a -Saxon derivative well

34

/e'e
e
\

e\J "e\e

I

,

gr d.

Ot

e

e

,

!

~

-1 0\

~ 0 ~

~

!).+!

309 keY

2+

~!

"0

o
BCM

Fig. 4.

( deg .)

Angular distributions for the transitions which are
fitted with L =: 0, L = 2 and L = 3 predictions of DWBA.

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

7)
8)
9)
10)
11)

K. Hubenthal, E. Monnand, and A. Moussa: Nucl. Phys., A128, 577 (1969).
K. R. Evans and F. Ajzenberg Selove: Phys. Rev., 165, 1327 (1968).
H. Taketani et al.: to be published.
Y. Awaya et al.: to be published.
E. Cheifetz, R. C. Jared, S. G. Thompson, and J. B. Wilhelmy: Phys. Rev.
Letters,~, 38 (1970).
S. Takeda, K. Matsuda, Y. Awaya, N. Nakanishi, T. Wada, M. Odera, and1. Kohno: IPCR Cyclotron Progr. Rep.l., 25 (1969); M. Odera, S. Takeda, and1. Kohno: ibid.,.if 29 ( 1970).
1. Kohno, A. Shimamura, 1. Sakamoto, T. Tonuma, S. Takeda, N. Nakanishi,
K. Matsuda, K. Koda, and T. Hamada: ibid\,
11 (1970).
T. Wada et al.: to be published.
K. Matsuda et al.: to be published.
A. G. Blair, J. G. Beery, and E. R. Flynn: Phys. Rev. Letters, ll, 470 (1969).
T. Wada: Reports of 1.P.C.R., 46, 21 (1970).

i.

35

4-3.

The 27 A 1 (3He, p)29Si Reaction at 21.89 MeV

N. Nakanishi, S. Takeda, Y. Awaya, and K. Matsuda

Measurements of differential cross sections of the 27 Al (3He,p) 29Si reaction
were done again under the same conditions as in the previous experiment 1) except thata set of solid state detectors was changed.
Emitted protons were detected by a J E - E solid -state counter telescope in bothexperiments. In the previous experiment the counter was composed of a 300 fJ,m ( j Ecounter) and two 3000 fJ,m (E-counter) totally depleted Li -drifted Si -detectors, andtherefore we were afraid of an influence from dead layers between two detectors.
Proton spectra obtained in the previous experiment show the depression at the energy
region corresponding to about 26 MeV. A Q -value of the reaction to the 29 Si groundstate is of 12.3 MeV energy, and thus 26 MeV protons correspond to the excitatedstates at an energy of 8 MeV. Unfortunately the levels excited through the (3 He ,p)reaction are relatively small in the vicinity of excitation energy 8 MeV and it is not

27Al ( 3 He I P ) 29 Si

Eh = 2 1.89 MeV
8 L = 30

0

X 20

2 000

<I)

c
c

o
-<=

U
<n

+'

g 1000u

Channe lNo.

Fig. 1.

Spectrum of emitted protons by the reaction 27Al (3He, p) 29Si.

Table 1.

Optical-model potential for the 27 Al (3He, 3He) 27 Al elastic
scattering.

V

Wvol

r

a

r'

a'

145.6

24.9

1.05

0.749

1.40

0.982

42.7

190.2

21.2

1.14

0.599

1.37

1.286

50.5

36

rare in the (3He,p) reaction that the differential cross sections corresponding to
low-lying levels decrease rapidly with scattering angles so the influence is notdistinguishable.
From the above view point we repeated the same measurements using an Ecounter which was a 5000 p,m Li-drifted Si detector. Fig. 1 shows a typical spectrum ofemitted protons. It is seen that an analogue level of the 29 Al ground state at an excitationenergy of 8.31 MeV is excited strongly. 2) Angular distributions of several low-lying
levels 3 ) are shown in Fig. 2.
Analysis on the reaction will be done in the future. Incidentally the optical-model
parameters of 3He elastic scattering are summarized in Table 1, and the angular
distribution are shown in Fig. 3. Optical-model parameters was obtained using an
automatic search code. 4 )10 1--- - - - - - - - - - - 101
'

..

.

:

grd

, 100 f---- - - --00••-----=----., - - - --10°1----.,

Ex = 3.07 MeV

- --

---.-

..--. --

...

00

000

<=b
co
--Q-----.---- l0\ 1------l1---;;:-()~--£x-= 3.62 MeV
CD

Ex=1.27MeV

o

000

o

00

o 0

, ..

o
000

o

.

1O\ ~---. ·- -- . -- -- - lO C I--- - - - --o.- . - - - -..

Ex=2.03 MeV

Ex = 4.08MeV •

10 1
0

o

o

0

r OO

I-

Ex=2.43MeV

0
0
00
0

Ex=8.31 MeV

0

o

o 0

o

o 0

0

o

o

°_n_-_ 10 t--- u ov
10° ~-----O--.,..,--."'1o- - - --0>----

o
I-

1
10

1
30

Fig. 2.

I

1
50

1

I

70

1

-

o

o 0

o 0

I-

1
90

110°
10

I

I

30

j

I

50

I

I

70

I

I

90

Angular distributions for low-lying levels of
29S'1.
.

37

100r;~----+-------4--------L------~

27Al (3He , 3He )27A l

Eh =21.89 MeV, 0- 1f---------+--~- _I:_~._~-------___+__-

102.~------+-------4-----~~~~---

103~------~------~------~------~

oFig. 3.

30

60

90

120

Differential cross section ratio ofelastically scattered 3He particles by
27AI. A broken line and a solid line
give predicted differential cross section ratios corresponding to the potential families I and II, respectively.

References
1)
2)
3)
4)

N. Nakanishi, S. Takeda, T. Wada, Y. Awaya,and K. Matsuda: IPCR Cyclotron
Progr.Rep.,1., 74 (1968).
L. Meyer-Schiitzmeister et al.: Phys. Rev., 187, 1210 (1969).
P. E. Endt and C. Van der Leun: Nucl. Phys., AIDS, 1 (1967).
T. Wada: IPCR Cyclotron Progr. Rep., ~, 87 (1968),

38

4 - 4.

E Ia s tic Sea tt e r in 9 of A Iph a Po r tic Ie s
from Even-Mass Molybdenum Isotopes

K. Matsuda, N. Nakanishi, Y. Awaya, and S. Takeda

Angular distributions of alpha particles elastically and inelastically scattered ofeven mass molybdenum isotopes were measured at the incident energy of 30.87 MeV.
Preliminary results were already described in Ref. 1). It will be necessary to analyze
systematically the elastic scattering data in order to perform the DWBA analysis of
inelastic scattering data in detail. Therefore the angular distributions have been remeasured over a wider angular range that is between 16 degrees and 72 degrees in
the C.M. system. Experiments have been done under the same condition as in theprevious ones for each isotope. Ratios of measured elastic scattering to Rutherford
scattering cross sections are shown with dots in Fig. 1.

\O-' I - - - - - - - + ------+-----'t-- -+ - - --"--------t-

80
SC.M.

Fig. 1.

Differential crosS section ratio of elastic
scattering to Rutherford scattering.
Experimental data are shown with dots.
Solid lines give predicted curves by
optical model.

39

Optical-model analysis has been made using an automatic search code. 2 ) An
optical potential form -factor is of Woods -Saxon type. The Coulomb potential is ofa uniformly charged sphere type and the radius parameter rc is fixed at 1.3 fm. A few
criteria are introduced in searching optical model parameters. (II !) Values of X 2 should
be as small as possible under the condition that fluctuation between each isotope would
not be very large. (2) Geometrical parameters of the real and 'imaginary parts areequal to each other and moreover common to all isotopes. (3) The isobaric dependenceof potential depth V and Wvol will show a smooth variation.
Table l.

Optical-model parameters.

Real potential V(MeV)

Imaginary potentialof volume type W(MeV)

X -value

Recommended
normalization
constant

100 Mo186.91

26.90

1.88

0.997

98 Mo

186.40

26.45

2.20

0.950

Mo

185.86

26.09

2.24

0.993

Mo

185.42

25.62

2.24

1.049

Mo

184.91

25.17

6.60

1.051

96
94
92

2

Geometrical parameters are fixed as follows: Radius parameterof optical potential r = 1.396 fm, diffuseness parameter a = 0.562
fm, Coulomb radius parameter rc = 1.3 fm.
In the first step, four parameters V, Wvol, r and a were searched to give the best
fit to each of the isotopes, and averaged geometrical parameters r and a were obtained
from five r's and a's, respectively. The parameters , rand a, were used for all isotopes.
In the second step, the trend of variation of each of the parameters V and Wvol was
examined to get a smaller X2 -value using fixed parameters Y, a and rc for each isotope.
In the last step, the four parameters V, W, rand were searched by the trial and error
method according to the above criteria for all isotopes.
Optical-model parameters obtained are given in Table 1 and predicted differential
cross section ratios are shown in Fig. 1 with solid curves. If fluctuations of potential
depth V and Wvol are neglected, the values of X2 can be obtained as about 2 except
100Mo and 92Mo isotopes. Particularly, for 92Mo isotope a comparable value withothers is not obtained, and is not improved by normalization. The DWBA analysis is
now in progress.

aReferences
1)
2)

K. Matsuda, Y. Awaya, N. Nakanishi, and S. Takeda: IPCR Cyclotron
Progr. Rep.,.i, 38 (1970).
T. Wada: ibid.,.b 87 (1968).

40

4-5.

The Manual of the Code for the Form Factor Computationof the Two-Nucleon Transfer Reaction

S. Yamaji

This is a brief account of the code to calculate the form factor of the two -nucleon
transfer reaction such as (3 He ,p), (t,p), (3 He ,n), and (a,d). The expression of the form
factor and the outline of the code are given in the Ref. 1) and details about themethod to prepare the input data will be given elsewhere. 2 ) The characteristic pointsof this code are as follows:
Two different treatments are available about the inducing interactiona)
The interaction between the outgoing and the captured particles is approximated as that acting between the center -of -masses of both particles. This treatment
was first formulated by Glendenning 3 ) which is called "cluster" in this code.
b)
The interaction is treated without above approximation, i. e., as a sum of
two -body interactions between nucleons in the outgoing and captured particles. This
treatment ,was first formulated by Lin and Yoshidat) which is called "micro ".
(1)(2)
Three different treatments are available about the bound state of eachnucleon in the captured particlea)The bound state of each nucleon is a harmonic oscillator wave function.
b)
The form factor of the internal region is obtained by the method (a), andthat of the external region is a bound Coulomb wave function adjusted to the separationenergy of the captured particle. Both wave functions are smoothly joined by varying
the matching radius.
c)
The bound state of each nucleon is a wave function solved in a given
Woods -Saxon well.

(3)
The form factor of the (a ,d) reaction can be calculated as well as those ofthe (3 He ,p), (t,p) and (3 He ,n) reactions
Using the expression A~~'jN) ,1) the form factor F gsj (r) for the zero-range
DWBA calculation is given in the following form.
F
f}
-r-sj

(r) = '\'L.,;
n,N

A(n,N)
f}

.

-r-S]

R

N1

(r)

.

As we made mistakes in the Ref. 1), the following corrections must be done:a)1o -- f2
0

in the expression of Qb'

41

b)

c)

{-1+1.5(B+H)}//2 fors=l{/12 fors = O.

D(s)=1 - 0.5 (B + H) }jJ4 ~ B2 in the expression of C n for "zero -range" and "micro ",If we use the form factor F fsj (r) obtained in this code into the DWBA 1 0 r DWBA 2 *codes, we obtain (J p~BA( (j), The absolute value of the differential cross section (J Cs' (0)in a unit mb/str is related to (J fdjBA «(j) as follows.
J(2J +l)
(J£

·(0)=

sJ

B

1

(2JA + 1) (2s a + 1)

5.093 X 10 3(J

D\VBA «(j)eSJ.

References
1)
2)
3)

4)

*

S. Yamaji: IPCR Cyclotron Progr. Rep" 2,,83 (1968).
S. Yamaji: Sci. Papers I.P.C.R., 65', '79 (1971)
N. K. Glendenning: Ann. Rev. Nucl. Sci., .!l,191 (1963); Phys. Rev., 137,
BI02 (1965).
C. L. Lin and S. Yoshida: Progr. Theor. Phys., ]1,,885 (1964).

T. Udagawa, H. Yoshida, K. Kubo, and G. Yamaura: Code INS-DWBA 1;
M. Kawai, K. Kubo, and G. Yamaura: Code INS-DWBA 2.

42

The Spin-Flip Probability

4-6.

In

the 92, 94Mo (p, p')

Reaction

T. Wada, H. Kamitsubo, S. Motonaga,
Y. Chiba, T. Fujisawa, and M. Koike*In the (p,p') reaction, the cross section (a), polarization (P), asymmetry (A) andspin -flip probability (S) can be expressed as follows:+ +_ + _+ ) / 2

=

(

(J

++ +

P =

(

(J

++ + a +_ -(J(J _ _A = ( a++ +

(J

+_ +

(J

S =

(

(J

(J

(J

/2 a
_+ - +- - a -- ) /2 a-+) /2(J-+ -(J - - )(J(J,

where the subscripts for the a mean the spin projection on z-axis, which is the normal
direction to the reaction plane. Plus sign (+) means spin up and minus (-) down. The
left is for'incident channel and right for final channel. In Fe region, the nuclei with
N = 28 and N = 30 give different angular distributions of cross section and asymmetry,

4040192 Mo ( p. p'l

94 Mo

2+

S. F.

S.F.
30

1/f\

20

20

~

• Ep=145 MeV

0'<

2+

Ex= 0.87 MeV

30-(p . p'lE, = \.51 MeV

o Ep=160MeV

LL

u.:

/
V

(f)

1 C'

J /

• Ep= 14.5 MeV(f)o Ep = 16.0 MeV
10\Or-----

300

60°

90°

I

120°

150°

0

SC.M

Fig. 1

30°
SC.M.

Spin -Flip Probabilities in 92,94 Mo (p,p ') reaction. The solid lines
are the results of collective model DWBA by Sherif code. 4 )* Institute for Nuclear Study, University of Tokyo.

43

but the angular distributions of spin -flip probability are not different so much. 1) For
lighter or heavier nuclei, no good data of spin flip exist to investigate the dependence
on the nuclear structure. The cross sections of (p,p ' ) for 92Mo and 94 Mo give different
angular distributions. 2) The spin -flip probabilities for these nuclei were also measured. The experimental conditions were the same as previously reported. 3) Fig. 1
shows the results. The 92Mo nuclei has 50 neutrons and then the first 2+ state isconsidered to be mainly composed of proton particle-hole states. But 94 Mo nucleus
has the component of neutron states as well and then more collective characters. The
angular distribution of cross section can be well predicted by collective model DWBA,
but not so well for 92Mo . But about the spin-flip probabilities, the DWBA predicts
the result for 92Mo fairly well. The angular distribution for 94 Mo has a sharp valleyaround f} c.m. = 1400 which cannot be predicted by collective model DWBA. In order to
see the resonance or compound effects the proton energy was increased to 16 MeV,
but the vall~ey was insisted. The major shell of proton and neutron differs in Mo region
but not in Fe region. This may have some effects on the spin -flip probabilities. It
rna y be interesting to measure the spin -flip probabilities for heavier nuclei.

References
1)
2)
3)
4)

D. L. Hendrie: Phys. Rev., 186, 1188 (1969).
T. Wada et al.: IPCR Cyclotron Progr. Rep., 1,42 (1969).
S. Kobayashi et al.: J. Phys. Soc. Japan, 29, 1 (1970).
H. SherifandJ. S. Blair: Phys. Letters, 26B, 489(1968).

44

4-7.

Spin FlipIn

the Inelastic Scattering of 3He on 12C

T. Fujisawa , S. Motonaga, H. Kamitsubo ,Y. Chiba , and T. Wada

Spin flip probabilities of 3He -particles in the reaction 12C (3He, 3He ,) 12C *(4.43 MeV) were measured at an incident energy of 34.7 MeV. The experiment was
carried out by the particle- r correlation method that has been proposed first by
Schmidt,l) and the detail of the apparatus has been already reported. 2 ) The spin flip
probability was measured in order to study the spin orbit term of the optical potentialof 12C for 3He-particle. The study of optical potential has been done concerning
elastic scattering 3 ) and the depth of the spin -orbit potential was selected to fit the experimental data at backward angles. The same potential gives the spin flip probability
shown in Fig. 1. It was calculated by DWBA with the f ull-Thomas type distortion of
spin-orbit potential proposed by Sherif and Blair. 3 ) The potential that has been
determined in order to fit the elastic scattering cross sections does not predictthe measured spin flip probabilities and the potential of which the spin orbit potential
depth is 2.5 MeV gives better agreement.

VR = 12 4.6 MeV
r SO=rR= 1. 1f m

Vs o = 4.75
Vso =3.5
Vso = 2.5

0 SO=OR =0.793fm

Ws = 1 5. 14 MeV'l: = 1. 566tm

E 3H

.=

34.7 MeV

0 1 =0.605fm

60

u..
c.f)

Fig. 1.

The angular distribution of spin flip probabilities of 3He for 12C and the predictionof DWBA.
A spin orbit potential of which depth is
4.75 MeV gave the good agreement forelastic scattering crosssections.

45

References
1)
2)
3)
4)

F. H. Schmidt, R. E. Brown, J. B. Gerhart, and W. A. Kolasinski:
Nucl. Phys.,~, 353 (1964).
S. Kobayashi, S. Motonaga, Y. Chiba, K. Katori, A. Stricker, T. Fujisawa, andT. Wada: J. Phys. Soc. Japan, 12., 1 (1970).
T. Fujisawa, H. Kamitsubo, S. Motonaga, K. Matsuda, F. Yoshida, H. Sakaguchi,
and K. Masui: IPeR Cyclotron Progr. Rep., ±, 46 (1970).
H. Sherif and]. S. Blair: Phys. Letters, 26B, 489(1968).

46

5. NUCLEAR PHYSIC S
Nuclear Spectroscopy
5-1.

The Level Structures of Light Even Strontium Isotopes Producedby 70,72,74, 76Ge (12C, 4n) Reactions
T. Inamura, S. Nagamiya, A. Hashizume, and Y. Tendow'Since Talmi and Unna 1) studied the level structure of nuclei in the vicinity of
90 Zr , the 88Sr nucleus has been taken as an inert core in the shell model calculations
for this regio n. It is, however, still an open problem to what extent the matrix elements of the effective interaction in proton configurations can reproduce those in thecorresponding neutron configurations. Recently Kitching et al. 2) have indicated that
seniority of the g9/2 neutron shell remains a useful quantum number within a few massunits of the 88Sr core. In addition, the simple shell theory of Talmi and Unna 1) has
been proved to be successful in describing the 86 Sr level structure. 3) On the other
hand, Zaitseva et al. 4 ) have suggested that the level structure of 84S r may be interpreted as the quasi -rotational band, although they did not find positive parity stateswith spin 6 or higher. Thus, it is of value to investigate experimentally how low-lying
high -spin states appear in 84 Sr; its level structure is expected to be similar to that of
92 Mo in the framework of the simple shell theory .1)
It is also of interest to study the level structure of 78 Sr which should manifest
the existence or non -existence of a magic gap at N = 40 (or 38). In this connection
it might provide a useful information to study the level systematics of 80 Sr , 82Sr and
84 Sr isotopes.
(1)

84S r

Gamma -rays from the 76Ge ( 12C, 4n) 84 Sr reaction were identified by excitation
functions, and time distributions were measured in the nanosecond region. No isomericstates in 84Sr were found having half -lives of more than 5 ns; if the level structure of
84 Sr was analogous to that of 92Mo , the 8+ isomer should be observed in the present
measurement. Anisotropies W( 45 0 )/W(900 ) of these r -rays were also measured with

"--

(f)
(f)

.0 .0

If ;;:co co"' N~ ...,...;

u

lOs

!

~

0
CD

u:;
0

,I

'"c::c::
0

.c
<...)

4

...... 10;t;

W ,(,,)

u _

'<t o
lOO
lO

l{)

00

\....
(f)

.,.

+

+-

=t t
. +-

u

<!<!

j

+N

~

"-

r

L

co

N

+N _

~ '>-

°I

+N

N

t ...
+

+-

'<t

+

C"'l 'c:.~

'<t

t

lO
•
lO-=

l{)

lO

- +

I'--

0 0

en

0

!I !

I

76Ge + 65 MeV 12C

c.fi
+

lO

t

+

(l)

lO~

--

V>

c::

=>

0

u

10

3

0

200

Cha nnel

Fig. l.

600

400

800

1000

number-Gamma-rays observed in the 76Ge + 65 MeV 12C reaction.

47

Table 1.

Gamma-rays identified as belonging to the 76Ge ( 12C , 4n) 84Sr reaction.

Er(MeV)

Anisotropyo0W( 45 )/W(90 )Relative intensity

Assignment
21+ ~ 0+*96 ± 14±0.14
1.34 ±0.13

1.042

87 ± 91.39 ± 0.14

6+ ~ 4+1.116

56 ± 91.35 ± 0.14

8+ ~ 6+

0.794

100

0.975

*

±7

1.36

4+ ~ 21 +*Ref. 4)

respect to the beam direction, and the 1.042 and 1.116 MeV r -rays were found to beof E2 by referring to the anisotropies of the 0.794 (2 1+ ~ 0+), and 0.975 (4+ ~ 21 ~ MeV
r -rays already known. 4 ) In Fig. 1 is shown the enery spectrum of r -rays observedin the bombardment of the 76Ge target with 65 MeV 1 C ions by using a 30 cc Ge(Li)detector. Relative intensities and anisotropies of these r -rays are listed in Table 1;r -ray energies have been determined within less than 1 keV. The ordering of the two
new E2 transitions of 1.042 (6+ ~ 4~ and 1.116 (8+ ~ 6+) MeV has been made according
to intensity.
MeV

0+

8+

3.927

4.0

3+
4+

5t
7+ 8+

V =2

6+

V =2

6t..
/
2+ 4+

1/= 4
V=2

4+

V=4

2+

V= 2

6+

2.8\ \~

2.& 5L __ __ l~
4+\ .769

3.0

6"1"

2.0

\-'-1.5J____ _ ~t

0 .794

2i

o

0+

a)

E xpt

Fig. 2.

0+b)Calc .

_2+_

1.0

o

Level scheme of 84S ra) observed in the present
experiment, b) calculatedby the shell model and c)
excited levels of 86S r usedin the determina tion of theeffective interaction.

48

On the basis of the present results low -lying excited levels in 84 Sr have been
constructed as shown on the left of Fig. 2. The placement of the 6+ level at 2.811 MeV
and of the 8+ level at 3.927 MeV has revealed the marked quasi -rotational band
~tructure of 84 Sr , which strongly supports the suggestion of Zaitseva et al. 4)
We have tried to interpret the 84 Sr level structure observed in the framework of
the shell model, introducing seniority up to v = 4 in the (Pl/2)-2 (g9/2)-2 and (g9/2)-4
neutron configurations. We used the energies of the positive parity states up to spin 8
in 86 Sr3) in the determination of the effective interaction. Results of our calculation
are shown in Fig. 2. On the right the states of 86Sr are presented for comparison.
The present calculation, as can be seen from Fig. 2, has ended in a complete failure
in describin*i the 8+ level at 3.927 MeV. Consequently, it can be concluded that, solong as the 8Sr nucleus is assumed to be an inert core, the 84S r level structure
cannot be interpreted by the shell model calculation.
The observed quasi-rotational band of 84S r is likely to be interpreted byintroducing the p-n interaction, * in view of the fact that the 7/2+ ground state of 83 Sr
seems to be an anomalous coupling state. 5)(2)78 Sr , 80 Sr , and 82Sr

Targets of 70Ge, 72Ge and 74 Ge were bombarded with 68 MeV 12C ions and rrays from the (12C, 4n) reactions were studied. The choice of the beam energy was
made in view of Q-values of the relevant reactions which are a little larger thanthe Q -value of 76Ge (12C, 4n) reaction. For identification of r -rays from these( 12 C, 4n) reactions the data on Kr isotopes 6 ) were very helpful because these isotopes
could be produced by the decay of the (12C, p3n) reaction products as well as bythe ( 12 C, 2p2n) or ( 12 C, a) reactions.
Gamma-rays identified as belonging to 78Sr , 80Sr ,and 82Sr are listed in Tables 2 ,3,and 4, respectively. Transition assignments were made on the basis of the observed
anisotropies and relative intensities. Time analyses of these r -rays were also made,and no isomers were found as in the case of 84 Sr. The cascade relation of 4+ ---. 2+---'
0+ was checked by a Ge(Li) - NaI(TI) coincidence measurement in each case.
The level structures of 78 Sr , 80Sr,and 82Sr proposed on the basis of the present
preliminary results are shown in Fig. 3. These nuclear structures appear to be ofquasi-rotational bands. Therefore, a magic gap at N = 40 (or 38) is not likely to exist .

Table 2.

Gamma-rays identified as belonging to the 70 Ge ( 12 C , 4n) 78 Sr reaction.

Anisotropy0
W( 45 )/W(900 )Assignment

Er(MeV)

Relative intensity

0.505

100 ± 11

1.32

±0.12

2+ ---. 0+

0.758

60 ± 71.28 ± 0.15

4+ ---. 2+

0.827

53

±7

1.30 ± 0.17

6+ ---. 4+* Private communication.

49

Table 3.

Gamma-rays identified as belonging to the 72 Ge ( 12 C , 4n) 80 Sr reaction.

Er(MeV,

Relative intensity

Anisotropy0
W( 45 )/ W(90o)Assignment

0.455

100

±6

1.27 ±0.06

2+ ~ 0+

0.666

67± 5

1.31 ± 0.09

4+ ~ 2+0.860

52 ± 71.36 ± 0.17

6+ ~ 4+

Table 4.

Gamma-rays identified as belonging to the 74 Ge ( 12 C , 4n) 81sr reaction.

Er(MeV)

Relative intensity

AnisotropyW(450)/W(90o)Assignment

0.576

100 ± 61.10±0.22

2+ ~ 0+o 756

100 ± 81.33±0.27

4+ ~ 2+0.822

36 ± 5

1.49 ± 0.36

(6+ ~ 4~

2.0 901. 98 1

1.332

1. 2630.505

oFig. 3.

2+

0 .455

o

05 76

o

Proposed level schemes of
78S r , 80Sr and 82Sr.

The authors are indebted to Dr. K. Ogawa, the University of Tokyo, for making
the shell model calculations.

50

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

1. Talmi and 1. Unna : Nucl. Phys., l2., 225 (1960).
]. E. Kitching, W. Darcey, W. G. Davies, W. McLatchie, and]. M. Morton:
Phys. Letters, 32B, 343 (1970).
M. Ishihara, H. Kawakami, N. Yoshikawa, M. Sakai,and K. Ishii :ibid., 35B, 398 (1971).
N. G. Zaitseva, B. Kratsik, M. G. Loshchilov, G. Muziol, Chang Tkhan Min.!. and
Kh. Shtrusnyi: Izv. Akad. Nauk, SSSR, Ser. Fiz. , ]2., 1283 (1969).
R. C. Etherton, L. M. Beyer, W. H. Kelley, and D. ]. Horen:
Phys. Rev., 168, 1249 (1968).
E. Nolte, W. Kutschera, Y. Shida,and H. Morinaga: Phys. Letters, 33B, 294 (1970).

51

5- 2.

Magnetic Moment of the 8 +State of 206po

S. Nagamiya, Y. Yamazaki, T. Nomura,
K. Nakai, and T. Yamazaki

At present, one of the most interesting problems in the study of nuclear magnetic
moment is to check the additivity of g-factors between one-particle state and twoparticle state, especially for high -spin states around doubly -closed shell regions.
Since the magnetic moment is very sensitive to the wavefunction of the state , the studyof additivity is a powerful approach for determining the configuration of the state ofinterest. Furthermore, it gives much information on the magnetic core polarization,
the mesonic effect, and so on.
Recently, many high -spin isomeric states in the 208 pb region have been foundand identified, and the magnetic moments of such high -spin states have begun to bemeasured. The present study is one of our work in series in this region. 1)"-'3)
Accoiding to the studies by Yamazaki et al. 4 ) and by Nagamiya and Inamura,5) the(7rh9/2) 8+ isomeric states have been systematically identified in even -A Po -isotopes
with mass number A of 200 -- 210 and half -life ranging from 100 to 400 ns. These 8+
isomeric states are of particular interest for the study of the magnetic core polarization in the 208Pb region especially of the effect of the polarization of neutron on the
7rh9/2 orbital.
Measurement was made by the ordinary time-differential PAD method. The r rays following the 204 pb (a, 2n) reaction, with Ea = 29 MeV, were detected by two
NaI(T1) counters placed at angles 60 and 1350 , and the time distributions of the

204Pb(cX,2n)206 po

8+

0.02

Slote

Ea = 29 MeV(T1/ 2 = 2 I 2 ns )8+212ns
6t- i 1573
395
4t-

t

1 178

477

~99
699

0.01
0+

j

o

zlz+
I

0

z z

III
Ct::

I

- 0.Q1-002

HO= 18.60:!:0.06 kOe

wl = 82.47! 1.20MHz

e = 135°
50
Ti m eFig. 1.

o(ns)

Levels of 206po and a typical example for the time -differential pattern for the 8+ isomeric state. Solid line isthe best-fit. Since the setting of the strength of the appliedfield is not so good, the amplitude is reduced to one -fifthof that at a matched field and the phase changes largely. 6)

0.583±0.016 e )
0.185

0.183

0.174

ogcoref)

0.009

0.009

0.009

OLSg )-0.003-0.003

0

Ogvib

0.774

0.772

0.766

gcal

0.143

±0.0060.151 ±0.016

0.159 ~ 0.010

gexp - gcal

g)

f)

a)
b)
c)
d)
e)

209

Bi

stable0.9067

0.583

0.180
0.009

0

0.772

0.135

Ref. 4).
Dubna Report, E6-5197 (1970).
R. Broda et al.
Ref. 1).
Ref. 3).
Present result. (Note that corrections of the Knight shift are not made for the values c), d), and e) listed above,since th e diamagnetic correction is estimated (Ref. 7» to compensate the Knight shift correction)
Calculated by the fornlUla of Arirna and Horie (Ref. 8»by use of the calculated v j 2 values for the neutron orbitals(L. S. Kisslinger and R. A. Sorensen: Mat. Fys. Medd. Dan. Vid. Selsk.,12., No. 16 (1953»,
Calculated by the fOYll1ula of Chemtob (Ref. 9».

9-/2----------------------- - -------------------------------------------------- --- -------------------------------------

0.926

5b )

212 ~

8+

206 po0.583

0.915 ~ 0.006 d )380 ~ lOa)

8+

208 po0.583

0.925 ~ 0.010 c )110 + lOa)

8+

2 1O pogSchmidt

T 1/2
(ns)

Summary of the observed g-factors of the (i'[ h9 )2) 8+
states of even - A Po -isotopes.

gexp

Ii'[

NucleiTable 1.

N

(J1

53

6+ -. 4+ (395 keY) plus 4+ -. 2+ (477 keY) C0l11posite peak were measured. A magnetic
field of 18. 60 ~ 0.06 kOe was applied up and down perpendicularly to the beam -detector
plane. Level sche111e of 206 po together with a typical result are shown in Fig. 1, fromwhich we obtaing (8+; 206 Po) = 0.92 6 ~ 0.016.
In this meaSUrelllent we have unfortunately set the strength of the 111agnetic fieldlarger than the matched strength at which the n = 3 stroboscopic resonance occurs. 6)
Thus, the observed aJllplitude shown in Fig. 1 is highly reduced into one -fifth of that
expected at the matched field. Because the present value includes a relatively large
error, we are planning to ren1easure this g-factor again.
Nevertheless, the present value is still meaningful for the rough theoretical
discussion. In Table I we list the present result together with the known g-factors ofthe (7[h972) 8+ states of 208 po and 210 po . Theoretically calculated g-factors, gcal'
derived fromare listed in the 9th column of the table, where gSchmidt is the Schmidt value, 0 gcoreis the correction to g-factor due to the magnetic core polarization,8) ogLS is thecorrection due to the two-body L'S force 9 ) and ogvib is the correction due to the surface
vibration of the Pb core. 10 ) The order of magnitudes of the latter two are not so large.
From the table the followings are to be noted:(1)
whereas,(2)

Both values of gexp's and gcal 's are all1l0st constant for all measured values,
the absolute valu es of (g1- g)' s are still large for all the cases.
ca
exp
The fact (1) implies that the 8+ state of 206 po certainly has th e 7[h / 2 configuration' and in addition that the effect of the magnetic core polarization of t6e neutron on
the proton g-factor is small, which is in good agreen1ent with theoretical predictions. 8 )As for the fact (2), it can be explained, as is well known, 2),11) by the anomalous
g.Q factor of the proton.

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

7)
8)
9)
10)
11)

T. Yamazaki, T. Nomura, T. Katou, T. Inamura, A. Hashizume, and Y. Tendow:
Phys . Rev. Letters, 24, 317 (1970).
T. Yamazaki, T. NOlllura, S. Nagamiya, and T. Katou: ibid., 12, 547 (1970).
S. Nagamiya, T. Nomura, and T. Yamazaki: Nucl. Phys., A 159, 653 (1970).
T. Yamazaki: Phys. Rev., g, 290 (1970).
S. Nagamiya and T. Inamura: Nucl. Phys., A 182 , 84 (1972).
J. Christiansen, H. E. Mahnke, E. Recknagei, D. Riegel, G. Wey er , and
W. Witthuhn: Phys. Rev. Letters, 11., 554 (1968); S. Nagamiya and K. Sugimoto
Osaka University Report, OULNS, 69 -3 (1969).
F. D. Feiockand W. R. Johnson: Phys. Rev. Letters,1l., 785(1968).
A. Arima and H. Horie: Progr. Theor. Phys., g, 623 (1954).
M. Chemtob: Nuel. Phys., A123, 449 (1969).
A. Bohr and B. R. Mottelson: Mat. Fys. Medd. Dan. Vid. Selsk., 27, No. 16 (1953).
S. ~Nagamiya and T. Yamazaki: Phys. Rev., C4, 1961 (1971).

54

5-3.

Magnetic Moment of the lowest 6 + State In 4 2 Ca

T. Nomura, T. Yamazaki, S. Nagamiya, and T. Katou

The lowest 6+ state in 42Ca is considered to be mainly of ]) f772 configuration.
In fact the recent measurement of E2 transition probability between the 6+ and 2750 keY
4+ states has proved very pure character of this configuration. 1) Then the g-factor of
the 6+ state is expected to give the g-factor of the Of 7 / 2 neutron in its two -particle
state and thus to throw a new light on the g-factor of the 41Ca ground state ( g(7/2-:
41Ca) = -0.4556) which is known to deviate largely from the Schmidt value for the Of 7 / 2
neutron (gsP = -0.546).
The g-factor of the 6+ state has been measured with the time-differential perturbed angular distribution method. The experimental method has been fully describedearlier. 2) The results are shown in Fig. 1 (a part of these results has been reported inRef. 2», from which we obtaing(6+: 42Ca) = -(0.50 ~~:~~)
It is a remarkable fact that the g-factor of the 42Ca 6+ state is closer to the
Schmidt value for the Of 7 ~2 neutron than that of the 41Ca ground state is. If we assume

the wave function of the 6'f state to be

42Ca

6t State

H = 24.20"!0.15 kOe-58.0"! 25 MHz
9 = - 0.50:!:0.03

H =31. 5:!:0.3kOe

(l/L=

0.2

z

+
-

z

0 .1

0.2

Beam
Burst

0.1

O

<VL=- 74 8!~.g MHz
9 =-0.495~g:g~

Beam
Burst

---~----tt---~~--~z-0.1

T i me (nsec)

Fig. l.

Time(n sec)Normalized time -differential patterns of the de -exciting!amma -rays from the 6+ state in 42 Ca excited by the. 0Ca (a, 2p) 42Ca reaction. A thick metallic Ca (natural)target was used. The data were taken at '135 degrees withrespect to the beam direction. The solid curves show thebest fits for (N~ -Ni)/(N~+Ni) = a+bsin2 (WMt+ (j), where
w'M is the Larmor frequency andis the beam deflection
angle due to the magnetic field.

e55

as calculated by Kuo and Brown,3) we can deduce the g-factor carried by the Of /7 2
neutron itself to be -0.57, which is nearly equal to the Schmidt value. The strong
violation of the additivity of the effective magnetic moments for these states can be
ascribed to the fact that a mixing of the core excited deformed states such as thosegiven by Gerace and Green4 ) is larger in the 41Ca ground state than in the 42Ca 6+
state (see Table 1).

Table 1.

The experimental g-factors for the v f7/2 configuration in com-parison
with the theoretical estimates.

Main Configurationa-0.4556 )gsp(Schmidt estimate)-0 50 +0.02.
-0.03-0.546-0.546ag 1st (1st -order correction)

0.07

ag f (correction due to thedeagdeformed states)c)

2nd

0.13

0.02

-0.42

-0.46

-0.59

-0.59

0.08f )

0.08 e )(2nd-order correction)

gcal (= gsP + agIst + ag 2nd + agdef )

-0.34

-0.38

g( vf

-0.67

-0.67

7/2

)d)

b)

Present result.

a)

From Ref. 9).

c)Calculated for the wave functions given in Ref. 4) and Ref. 11).

d)

g- Factor carried by the Of 7 / 2 neutron itself (= gexp -e)Taken from Ref. 6).

! f)
IThe same value as for the 7 /2- state is assumed.

~

ag).

b)

56

Table 2.

The g-factors of f7/2 proton and neutron.

Empiricala )Theoreticalr~--------------~A~----------------,

Single -particle value
Schmidt value-0.546-0.6321.655

1. 741

1.109

1.109

Sum

-0.67 b )a)

The g-factor carried by the Of 7 / 2 proton or neutron empiricallydeduced in the text.

b)

Present result.

c)

1.09

Taken from Ref. 10).

If we take into account the correction due to the configuration mixing in thesecond-order perturbation theory, 5),6) the empirical g-factor of the Of 7 / 2 neutron
deduced from the present result falls outside the Schmidt limits. Recent empiricalanalysis 7) shows that the orbital g-factor in a nucleus is enhanced by 0.1 T z ( T Z is
+1 for proton and -1 for neutron), which agrees with theoretical consideration based on
the mesonic exchange theory.8) The present result seems to support the anomaly of
the g.Q-factor also in the 40Ca region (see Table 2).

References
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)

T. Nomura, C. Gil, H. Saito, T. Yamazaki, and M. Ishihara: Phys. Rev.
Letters, 25, 1342 (1970).
T. Yamazaki, T. Nomura, T. Katou, and S. Nagamiya: lPeR Cyclotron
Progr. Rep.,.i, 74 (1970).
T. T. S. Kuo and G. E. Brown: Nuc1. Phys., A114, 241 (1969~
W. J. Gerace and A. M. Green: ibid., A93, 110 (1967).
M. Ichimura and K. Yazaki: ibid.,...Q2, 401 (1965).
H. A. Mavromatis et al. : ibid.,..§Q, 545 (1966).
T. Yamazaki, T. Nomura, S. Nagamiya, and T. Katou : Phys. Rev. Letters,
25,547 (1970) ; S. Nagamiya and T. Yamazaki: Phys. Rev., C4, 1961 (1971).
For example, H. Miyazawa: Progr. Theorl. Phys.t K1-.2.., 801 (1951).
E. Brun et al. : ibid. ,.2, 166 (1962).
K. Nakai et al. : Phys. Rev. Letters., 27, 155 (1971).
B. H. Flowers and L. D. Skouras : Nucl. Phys., A136, 353 (1969).

57

5-4.

Decay of 87Zr and 85Z r

Y. Awaya, T. Katou, Y. Tendow,
A. Hashizume, and T. Hamada

The decay of 87 Zr and 85Z r has been investigated to study the level structure of
the neutron deficient yttrium nuclei systematically. The isotopically separated 86Sr
(N0 3 ) target was bombarded ~y 3He particles from the cyclotron. The bombarding
energy was 18.5 MeV for the S-6 Sr (3 He , 2n) 87Zr reaction and 44 MeV for the 86 Sr(3 He , 4n) 85 Zr one. The zirconium component was chemically separated by the solvent
extraction.
The measurement of single spectrum of gamma -rays was made by using a 23 cm 3
Ge (Li) or an anti -Compton spectrometer which consists of the 23 cm 3 Ge (Li) and anannular type 6 inch X 6 inch NaI (Tl) longitudinally split by halves.1) The gammagamma coincidence measurement was made by the 23 cm 3 Ge (Li) and a 3 inch X 3 inch
NaI (Tl). The energy spectra of positrons and conversion electrons were obtained byusing a Si (Li) detector with a depletion layer of 3 mm. The spectrum of X -rays wasmeasured by a Si (Li) detector specially designed for X -ray measurements.2) The preliminarily obtained gamma -ray spectrum of 87Zr was reported previously by the authors. 3 )
(1)

Zr-87

Though the spin -parity of the ground state of 87Zr has not been assigned, thevalue of 9/2+ is most plausible from the standpoint of the shell model. In this mass
region, many nuclei have an isomer which originates in the shell configuration of the2pl/2 and the 19 9/2 orbits. If the 87mZr= 1/2-) exists during the measurement,
it should be taken into account when the decay scheme is discussed. But as the X -raysof the zirconium could not be found definitely about an hour after the bombardment andin most cases the measurement was begun at that time, out present study is considered
to concern only the ground state decay of 87Zr.
The half-life of 87Z r has been determined to be 104.0 ± 10.5 min from the decay ofthe positron spectrum and to be 103 ± ' 4.5 min from the decay of the 1.227 MeV gammaray, 'Yhereas the previously reported va lue is 1.6 h.4) The maximum energy of thepositrons has been estimated to be 2.28 ± 0.05 MeV. The spectrum of gamma -rays
obtained by the anti -Compton spectrometer is shown in Fig. 1. The energies of gammarays assigned to 87 Zr and their relative intensities are listed in Table 1. In addition to
the gamma -rays listed in Table 1, the 200 keY, 921 keY, 1147 keY, 1590 keY, 2434 keY,and 2720 keY gamma -rays were also detected but because of their weak intensities thedefinite assignment was difficult. The results of gamma -gamma coincidence measurement are summarized in Table 2. The cascade gamma -rays were also checked fromthe comparison of the sing Ie gamma -ray spec trum with that obtained by the anti -Compton spectrometer with the source on the Ge (Li) detector. In the latter case, the intensity of gamma -rays which coincide with any others decreases relatively to those in the
single spectrum. The coincidence measurement between the positrons (and conversion
electrons) and the gamma -rays which coincide with the annihilation gamma -ray was
made, but because of the low counting rate, a definite result as to the end -point energyof each positron branch has not been obtained yet in the present stage. In this meas-

Orr

58

Table 1.

Gamma -rays of 87Z r .

Present work

Previous workS)r

E r (keV)'"'\

I r (reI.)I

E r (keV)

I r (reI.)

611 ± 14±16332:1

22:1

771 ± 24±27722:18± 1±220 ± 37942:1102:2

797 ± 16 ±28362:122:1

973 ± 14±11024 ± 1

282:2

±1

22:1

793

973 ±26±310481160 ± 2

7±31159 ± 18±11202 ± 3

12 ± 51203 ± 15±1±135 ± 31210 ± 1

332:2

±1

3±2

1210

1216
1228 ± 1

1001227 ± 1±1.51400 ± 1.5

1388

'\

100
3±1
4±1

1410 ± 1.5

+ 0.5
1-

1657 ± 23± 1

1692 ± 1.5

+ 0.5
1-

1806 ± 2

5±21808 -+ 1.5

3± 11820 ± 2

3±21821 ± 1.5

3±11857 ± 1.5

2± 1

1862

± 1.5

±0.5
2 ±1
1

2165 ± 5

32:2

2172 ± 2

21832:5

32:2

2183

±1.5

3±1

2220 ± 3

10 ±22222 ± 1.5

9±2

±3

5±1

'
2615 -+ 1.5

3±22883 ± 2

2 _+ 1.5

2615

59

10 6

"I

.s:>

a..

-- '-

<>

L f)

",

f

x

0

"
C

d

CD
("')

t'-N
N

1

0<.0

u

'-

10 3

"

0

N
N
N
N

U

10 2

N
en

-

enO

~~O
--~

NM
t'--en

t'--N

t'--N

Lf)cn
<.0<.0Lf)<.O

en en

NN

;0'

o

160 0
3600

1 800
Channe lFig. 1.

The gamma -ray spectrum of 87Zr. Energies are in keY.

Table 2.
Gate

Er

511

611
772
794, 797
973
1024
1048
1203
1210, 1216
1227
1388
1400, 1410
]693
1808
1857

?

730
-., 780

Results of the gamma -gamma coincidence.
760-., 840++

940--10301030-., 1060

+

+
+

+

+
+

+

+

}+

}+

}?

}?

?

?

+
+

n umber

+

+

+
+

+
+

1110
-- 1170+1180-- 1220
+
+
+
?
?
?

1220
--12601350--1500

+

+
+
?

}?

}+
?

+
+

?

+

urement, however, the conversion electron of 345 keY was detected when the gate forthe gamma-rays was opened at 710------820 keY. This suggests the existence of the transition of about 362 keY though the gamma-transition is too weak to be detected.
On the basis of the ~resent results and the result of the 86S r (3He, d) 87y reaction
obtained by Maher et aI., ) a tentative decay scheme of 87Z r is proposed in Fig. 2. The
spin-parities are based on the assignment of Ref. 6). On the analogy of 89y the spinparity of the 1405 keY state and/or the 1591 keY state is considered to be 7/2+, A few

60

1 ld4m in

3406

}

~~6~
2d 5/23 1 95 - 35 112
3090 _ _ }~~ ~ ~
2 d 5/2=

299 6-- 0 -

all)I t 5/2

2407 - 2278 - 2203 2085 - -2 d 5/2
1 t 5/2
19 9/22 p 3/2

184 8 -

2 p 312-

1 605 - -1 155 - 98 2 - 793 -

~~

260 3
256 4
2 55 3

-~

220 3
207 3

(1)

co=
0<0
co
1608
1 59 11405

1 9 9/2

2 d 5/2

-

~

=

~~

_ <t
-N

-

I g 9/2

Il) N M NM
-I'- co N CO
<0 - - NCO
NN NNN

eI)

<t

~

~

II

;) (9/2 +)(512 +)

N

>

~

If)

0

0
+1

co

<.D

C""i

N

co

- - ~~ NN

79 4

I'(1)N1'-'"<0,'/ I

1 15 3

2p 3/2
I t 5/2

8<t(')11)

'~+

/<

co

<0

//512-

(')

<t
'"
I'-

380 - -

rr -

MI'-

~2907 --

2730 - -

1

340 6
326 4

N
I'I'-

38 1

( 14 h )

co

I

9/2 +

(')

0--

2 p 112( n1 j )Ex
B7yFig. 2.

Ex( from re f . 6)

112+

/

(In)

(80h)

B7y

The proposed decay scheme of 87Zr. The levels excitedby the 86S r (3He, d) 87y6) are also shown for comparison.

Gamma-rays of 85Z r .

Table 3.

Pres ent work

From Ref. 9)
/'

\

A

(

"

E r (keV)

I r (reI.)E r (keV)

265.8

7

265.9

6.6

357.8

3.3

Ir(rel.)

415.9

63

416.1

58

454.0

100

454.1

100

621. 7

2.2

636.4

3.5

781.6

7.8

798.7

4.5

1199.09.91414.92.2

1769.1

3.9

61

gamma -rays are not included in the decay scheme. Although the values of the transition energy differ by 1 keY or so from those of gamma -ray energy in Table 1 for somecases, the values in Table 1 are used in the decay scheme. In order to make the decay
scheme more definite, the study is still in progress.
(2)

Zr-85

Various half-lives of 85 Zr ranging from 6,.......,8 min to 1.5 h have been reported 7 ),8)
based on observations of th~ activity of the daughter nuclide, 85y. Recently, Doron andBlann 9) assigned three gamma-rays to 85Z r and proposed a half-life of 7.7 .± 0.5 min.
Their assignment was based on the measurements on three different heavy ion reaction products and their excitation functions.
In our experiment Zr isotopes of mass number from 85 to 89 were separated by
the solvent extraction, and the measurement was started usually about 6 min after theend of bombardment. Many gamma-rays were assigned to 85 Zr and the half-life wasdetermined to be 8.0 ± 0.5 min. The assigIlJment was made on the basis of their decay
periods. Energies and relative intensities of the gamma -rays are summarized in Table
3. In addition to the gamma-rays listed in Table 3, the 1720 keY, 1865 keY, 1920 keY,
1923 keY, 1993 keY, and 2127 keY gamma-rays were also detected, but a definite
assignment was difficult because of their weak intensities. The gamma -ray spectrumof 85Z r is shown in Fig. 3. The study is still in progress.

-->-'

_0

U)~

:SL

c

c

N

°
<..0
<..0
N

~

~

-j~

V>

c

::>

o

jI

U

~

tn

<..0
I"-

;::r

-

10 1 -oCannelFig. 3.

numbe r

The gamma -ray spectrum of 85 Zr. Energies are in keY.

62

References
1)
2)
3)
4)
5)
6)
7)
8)
9)

M. Okano et al.: IPCR Cyclotron Progr. Rep.,.b 110 (1968).
M. Okano et al.: ibid., ~ 75 (1971).
Y. Awaya et al.: ibid., b 109 (1968).
C.M. Lederer et al.: "Table of Isotopes", John Wiley and Sons, N.Y., p. 222( 1967).
R. Arlt et al.: Contrib. Intern. Conf. Nucl. Struct., Dubna, p. 10 (1968).
J.V. Maher et al.: Phys. Rev., C3, 1162 (1971).
F .D.So Buternent and G.B. Briscoe: J. Inorg. Nucl. Chern., 25, 1699 (1969).
N.G. Zaitseva et al.: Sov. J. Nucl. Phys., lz. 273 (1965).
T.A. Doron and M. Blann: Nucl. Phys., A161, 12 (1971).

63

5-5.

New Isom er

In

148Gd

A. Hashizume, Y. Tendow, T. Katou, and T. Inamura

In the course of an investigation of new isomeric states by the detection of delayedr -rays between the natural beam bunches of the cyclotron, it has been found that an
isomeric state exists in l48Gd. Most of the features of the experimental method havebeen described in a previous report) Essentially it consists of taking nanosecond
timing distribution of the reaction r-rays detected by a Ge (Li) detector.
A 147Sm target enriched to 97.9 % and deposited on a 4 J.l m Mylar film and atarget of natural isotope of La in a metallic form were bombarded by 20 to 45 MeV
a-particles to induce (a, x:nr) reactions and 65 to 88 MeV nitrogen ions to induce(N, xnr) reactions respectively. Figure 1 shows single r -ray spectra from the former
reaction for several bombarding energies. Figure 2 shows the relative excitation
function for the r -rays attributed to the (a, 3n) reaction (except 940 keV r -rays). An
excitation curve taken with a 786 keV r -ray in Fig. 2 shows a very broad peak which isinterpreted by the existence of two unresolved r -rays, assuming that one of them gives
a similar excitation curve to that of 940 keV. Normalizing the curve from 27.5 to 32.5
MeV of 940 keV to that of 786 keV, one obtains the dashed curve which gives the characteristic of (a, 3n) reaction. The energies and intensities of these r -rays at 40 MeV
bombarding energy is shown in Table 1.

Q)

c
c
0
.I:

U

30

'"c

:::>

0

U

25

20

o

500

1000
Channe lFig. 1.

1500

numberSingle r-ray spectra from the 147 Sm (a, xn) reactions.

64

105~--------------------------~(ex, 3n)r·',....-.---..

/.

• . . . . . . .,395 keV632 keV,.

I
10 22~0------~3~0------~40~------5~0~M~eVFig. 2.

Table 1.

TH,ical excitation curves for the
1 7Sm (a, 3n) 148 Gd reaction.

r -ray intensities and anistropies.
00

E r (keV) JE

Ir ±JIW (43 )/W (90 )394.9 ± 1.0

82 ± 171.36 ± 0.03

632.0 [± )1.0

101 ± 21

1.28 ± 0.02

784.3 -+ 1.0

100

1.32 -+ 0.02

882.9 ± 1.0

44± 91.30 -+ 0.05

The r-ray spectra from the reaction induced by the heavy ions are so complex
that one could not distinguish clearly those r -rays from (N, 5n) reaction. Though themost intensive ones observed in 147Sm (a, 3n) reaction are also found when the incident energies of nitrogen ions were 80 and 85 MeV (Fig. 3). Figures 4 and 5 show
prompt and delayed r -ray spectra from the interested reactions. The decay curves ofeach delayed r -rays are shown in Figs. 6 and 7. These curves were analyzed by theleast square method using a program (UNIDEC) and the half-life was determined to be
16.2
0.9 ns for the curves in Fig. 6 and 17.9 ± 2.5 ns for Fig. 7. Comparing the
curves in Fig. 6 with those in Fig. 7 the ratios of intensities for delayed to prompt

±

65

Q)

c:
c:
C

-<=

o

Ul

c::
:::J

o

o

o

1000

500
ChannelFig. 3.

2000

1500

numberSingle r -ray spectra from the 139La (N, xn) reactions.

lD

roO
roq

I~

\.-~~
Ge(n n/ )

I

J

o

~

500
ChannelFig. 4.

,'\....,lnumber

Prompt and delaled r - ray spectra
observed in a 1 7Sm + 38 MeVa reaction.
Spectrum (a) shows prompt and spectra (b)and (c) show delayed (about 50 ns and 75ns) r -rays. The ordinate of each spectrum
are relatively normalized.

66

><l.l
.;,&.

L.()
(J)
0')

I

139 La ( N, 5n) 148Gd

-

L.()

I

\
<l.l
C
C

o

..c::.
(.)

o500
ChannelPrompt and delayed r -ray spectra observed in a 139La + 87 MeV
N reaction. Spectrum (a) shows prompt and spectra (b), (c) and (d)shows delayed (about 27, 54 and 81 ns respectively) r-rays.

Fig. 5.

148
147Sm (0:'. 3n ) Gd

r·

/1

f

rt
t

I

•

I
/

i

// /
{

0

~

I

I

!}/!

.;,&.

0
<l.l

¥

I

Q)

>

I

,i
~/
/r
ttr
J/

0

~

/;/

633keV

~

goA

I II

.5:
Q)

0::

~I

keV

886

..

/

viy/§;/+-'

number

o
Q)

I....

o

.:.::.
o

keV

395

Q)
~

Q)

>
+-'

o

Q)

0::

l

r.yrf

;I

~

o

V

o
T

T

Fig. 6.

Decay curves for the r -rays
from 147S m (a, 3n) reaction.

Fig. 7.

Decay curves for the r -rays
from 139 La (N, 5n) reaction.

67

r-rays corresponding to the same energies are greater for 147Sm (a, 3n) reaction
than those from 139La (N, 5n) reaction. This fact indicates that the isomeric state hashigh angular momentum, because, in the de -exci ting process from the compound
nucleus with higher angular momentum made by heavy ions, the high spin states have achance to be excited more often than the lower spin states if their energies are com parable.
Very little is known about the excited states in 148Gd. Toth and Rasmussen2 ) has
only observed 0.780 and 1.12 MeV r -rays by a scintillation spectrometer in the decayof 148Tb. Though the ratios of the intensities of prompt to delayed r -rays, the intensities of each single r -rays and their anisotropies have been observed, we are not yet
certain about the order of de-exciting r -rays from the isomeric state except 633(4+ ~ 2+) and 786 keV (2+ ~ 0+) transitions, because some inconsistency exists on therelative intensities of delayed r-rays. The isomeric state lies at least above 1.814
MeV and the half-life is 16.7 0.9 ns. The analysis is in progress.
Though there are son1e theoretical approaches on the level structure in thisregion 3 ),4), no prediction has been obtained on the levels in 148 Gd . The extra protons
outside the Z = 50 closed shell are distributed among the five available single -particle
levels, i.e. 19 7 / 2 , 2d5 / 2, 2d 3 / 2 , 3s 1 / 2 • and 1h11/2' Among them., 1h11i2 could contribute to the isomeL For the orbits of two extra neutrons outside the Z = 82 closed
shell, 2f7/2' 1h9/2' and li11/2 are important for high spin states.

±

References
1)
2)
3)
4)

T. Inamura, S. Nagamiya, A. Hashizume, Y. Tendow, and T. Katou: IPCR
Cyclotron Progr. Rep., 4, 67 (1970).
K.S. Toth and J.O. Rasmussen: J. Inorg. Nucl. Chern., 12,236 (1960).
M. Rho: Nucl. Phys., 65, 497 (1965).
P. Haapakoski, T. Honkaranta, and P.O. Lipas: Phys. Letters, 318, 493 (1970).

68

6. NUCLEAR INSTRUMENTATION
6- 1.

Deve lopment of a Wire Spark Chamber with Ferrite Cores
for a Broad Range Magnetic Spectrometer

J. Fujita and S. Takeda(1)Introduction

Several methods 1) have been developed in order to detect posi tions of charged
particles in a broad range magnetic spectrometer. In a previous paper2) we reported
a method performed by many solid state detectors aligned on the magnetic focal plane.
This multi -detector system will be used in heavy ion experiments. For experimentsof lighter particles such as proton, deuteron and a -particle, another method was considered.
A model of a wire spark chamber with ferrite memory cores has been built andis going to be tested. Waters 3 ) reported that conventional ferrite memory cores could
be used with a wire spark chamber for recording spark locations. Galster 4 ) ob~ained
spatial resolution of approximately i 0.3 mm in a wire_spacing of 1 mm.
(2)Principle

Two wire planes are faced each other but the directions of wires on the two planes
are orthogonal, that is, vertical and horizontal. Vertical wires pierce through thememory cores and fall down to the ground. A negative high voltage pulse is supplied
to the horizontal plane. Then, if a charged particle passes through the spacing between the wire planes and ionizes gas atoms along its passage, there occurs a sparkand the spark current magnetizes a memory core to one stable state. Then a current
opposite to the spark current is made to flow. The memory core undergoes transition
to the other stable state and at the same instant, information of spark location is perceived by a sense lead.
(3)

Structure

Outline of the chamber is shown in Fig. l.
A stainless steel wire with a diameter of 0.1 mm is used. Twenty horizontal and
50 vertical wires are aligned and the interval between wire planes is 2 mm. This
space is made by inserting an epoxy frame 2 mm thick between wires. The wire spacing is 1 mm. So the operating area of the chamber is 20 X 50 mm 2 . One end of thehorizontal wires is pasted with electrically conductive glue and connected to a clearing
voltage source via a RC high pass filter. The other end and Al plate of 30 x 30 mm 2
in area are separated by a Mylar film 9 f.l m thick and form a coupling condenser ofabout 30 pF. A high voltage pulse is supplied on this Al pIa teo
Ferrite cores used here are R456 manufactured by TDK Electronics Co. The
dimensions of core are 0.76 mm in inner diameter, 1.27 mm in outer diameter and0.39 mm in height. Tra,nsition current of the core is more than 400 rnA and then acounter electromotive force of 80 mV occurs in a sense lead.
The epoxy frame with wires and cores is set into an acryl chamber with an innervolume of 150 x 95 x 25 mm 3 . Windows of 20 X 50 mm 2 are opened on the front and69

Clearing
voltage, - - - - - - - - 0 -HV

pu lseAl plate
9,um myler f ilm

Conductiveglue

Horizontol wire2,

L--f '
lmm

Epoxy frame

Vertical wire---_ -=-~ L _

1

r --

--,-

1
-- - ---- ------- 1--1----------,---

Horizont al wires
withI mm interval-- --------1-- -ory core

Conductive glue
(G round)Fig. 1.

Outline of wire spark chamber withmemory cores.

Pushbutton~~~~--~~------------------------4 V

Un i vi bratar
1f

Emitter
Follower
Read current
generator
V

..R-

1-16

\7-32
33-48
49-50

JL

2

JL

3

JL

4
-y-I

~------

2

16

Fig. 2.

Block diagram of electric system in wire spark chamber.

70

rear walls. Thin duralmin foil makes the interior of the chamber gas -tight. Two small
holes are prepared for gas flow . Terminals for a high voltage pulse, a clearing voltage,
4 read -out and 16 sense wires are also provided on the rear wall. The outer size of thechamber is 180 X 125 X 55 mm 3 .
(4)Electronics

A block diagram of the whole electric system is shown in Fig. 2. A charged
particle passing through the chamber produces an electric pulse in a photomultiplierwith a plastic scintillator. The pulse triggers a high voltage pulser. Spark occurs at
a pOSition of particle track on the wire planes and a core threaded by a sparking wire
stores information of the position. While the pulse fed through the 1st gate is delayedfor 500 nsec and sets the 1st gate and the 1st group count flip-flop. The 1st gate F.F.
closes the 1st and H.V. gates. In addition, the pulse delayed for 1 msec sets the 2ndgate F.F. which opens the 2nd gate, and is sent to group count F.F. and strobe circuit.
Group count F. F. is composed of 4 digital counters and every pulse advances by one
digit. At the same time with its count, each F.F. gives a selected pulse to read current
generators. The cores consist of four groups with 16 cores threaded by read -ou t wires.
There are 16 sense lines perpendicular to the vertical wires of chamber and if information exists in memory cores, it is transferred to 16 parallel shiftregisters by wayof each sense amplifier, discriminator and opens the 2nd gate. Strobe circuit searches
out the contents of the shiftregisters. If the register stores one bit, its address digit istransformed to a corresponding parallel binary code by diode matrix and sent to 1024
channel pulse height analyzer. A CLADC signal which indicates completion of memory
function in the analyzer appears after several microseconds. CLADC passing throughthe 2nd OR advances the 16 counter by one count and also the contents of the next
}f:..sec
The 1st gate input

L-

The 1st gate Out<=----,
I ms '

The 1st gate F. F. Out
Group count F. FlOut
I ms De lay
The 2nd gate F. F Out
The 1st OR Out
G.C FF 2 Out
Read current Gen. Ou t'--I

Open the I st gate
r-

:

r4-

+-

'Close the 2n d gate
~d cycle ov er gat e

3

2nd ate open10).lSlOps
5OQ'ls lOp s ,5OOf~, SlOPS ,::,/dlsappear-1==-~---;;;;::::;-,-------'====-T------+=~ r=--:===-___=;...,--_f"'------;,~---T
::

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

~:

11

1

::

:::

"

:1

I:
:'

The 11 th care transition

,

I

I

5 ch. Di Scriminator Out
5 ch. 2nd gate Out

JL

Q of 5 ch. shiftreg ister~r--~--------L___~--~----------~----~Q of othe r shif t reg isters,

10).ls Delay Out

II

The 3 rd OR Out
Res et OR 3 Out
5

St r obe Out~o Out of Oiode motriJt
2'
2'
2'
2"
2s

"
"
"
"

4

IOOnV :::~' 700ns

GC. F. F 3 Ou t
R.C Gen . 2 Out,

1I1I1I1I1 .. i

200ns /-;lIII~~O,J.lS~--,----,---

-,-

"
"
CLADC ,n 1024 th . P. H . A .

68
lEi
11111111111 1

,
,
,

i
17

,
32'

i

i

1I1iiiilililiiii i~i iiliiliIII I 11~

111.1111111 11111

1fl lIlIl 1.11 11111

I

"
6'1 ,

49

iiilllllllll[III ;:liiliil. lill. i.V;---"
"
"
"

,
,

::

"

'
'

"

::

:2.5ps-------,~

"

"
"
"

--------~I----~~-------,~"""

G.C . F. F 4 Out
R.C Gen . 3 Out
Cycle-over F. F.
R .C . Gen. 4 Out
Reset OR lOut
Cy cle over gate Out----------------~----~~"""

set ,Cyc le-ove r FF.

~t
:'

"

::
"

~
:

disappear

Fig. 3.

Timing flow chart of pulses occurring in the electric
system of a wire spark chamber.

71

register are strobed out. If there is no content, the 16 counter merely advances by one
count via the 3rd OR, 500 nsec delay generator and the 2nd OR. When the strobe of
the 16 registers finishes, the shiftregister is reset and at the same time next group of
the cores is read out. The same work is repeated four times. At the instant when thelast core group is read out, the cycle-over F.F. rises to high level. And it falls down
to low level at the end of strobe function. The falling edge of cycle-over F.F. generates a reset pulse. This pulse resets the 1st and 2nd F.F. So the 1st and H.V. gatesare opened, and the 2nd and cycle -over gates are closed. The cycle -over gate prevents
the strobe system from free running. Thus the total cycle is over. The high voltage
pulser has already recovered during this cycle. A timing flow chart is shown in Fig.
3. Almost all of the parts of this electric system are constructed by integrated circuits.
(5)

Test results

Test results of the electric logic system using a pulse generator show a good
performance. A high voltage pulse of 7 kV brings about visible sparks at several
points in the gap. At present two difficult problems still remain. The first is thatthe logic system suffers disturbance from occurrence of spark. The second is thenoise picked up by sense leads from the read current pulse.

References
1)
2)
3)
4)

G.L. Miller et a1.: Nucl. Instr. Methods, .2.1:., 389 (1971).
J. Fujita and S. Takeda: IPCR Cyclotron Progr. Rep., 1-, 109 (1970).
J.R. Waters: Nucl. Instr. Methods,1.1 126 (1963).
S. Galster et al.: ibid., 46, 208 (1967).

72

6-2.

A Mechanical Beam Chopper for Millisecond Beam Pulsing

A. Hashizume and H. Kumagai

In the determination of life of isomers or of very short-lived radioactive nuclei
by a pulsed beam technique, the life to be measured is limited by the interval of thepulses. In the Cyclotron, the frequency of an oscillator varies between 6 Hz and 13.5
Hz depending on the kind of accele:t;ating particles and their energy. This means if we
utilize only the natural beam bunch, the range of half-lives to be measured is restrictedfrom several nanoseconds to a few hundred nanoseconds. The shorter one is limitedby the time jitter of pulsed beam originated in the acceleration mechanism and by thecharacteristics of fast responses of electronic circuits employed. A typical time
resolution (FWHM) of fast component of r-rays detected by a Ge (Li) detector andanalyzed by a time-to-amplitude converter, is about 10 ns.
To obtain a longer interval of pulsed beam, there are generally three methods:
The modulation of an ion source, the deflection of a beam by a deflector and themechanical chopper. A beam deflector operated by pulsed voltage is now under construction for measurement in the microsecond region. A mechanical chopper in thisreport is p~anned for the measurement of half -li ves in the millisecond region. When
compared to a neutron chopper a metal plate of proper thickness is sufficient to stop
the accelerated particles, but there is a difficulty to generate a torque in vacuum.
However, because of a recent development of precision D.C. motor which can be operated in vacuum, its realization becomes very easy.
A mechanical part is shown in Fig. 1. It consists essentially of an aluminum

Fig. 1.

Mechanical chopper.

73

disk of 115 mm in diameter and of 2 mm in thickness. The ratio of angles from thecenter of a disk to the window and the blind portion has been chosen to be one -eighteenth.
There are two, four, or eight windows in a disk. The disk :is attached to the axis of a
precision D.C. motor designed specially for operation in vacuum. The speed of the
motor can be controlled from 250 to 5700 r.p.m.; that is, we can obtain the interval ofpulsed beam from 240 ms with one window to 1.3 ms with eight windows.
A lamp and a photo-transistor system send a triggering pulse in each time ofbeam passage to initiate a sawtoothed-wave gene r ator. The output of the generator is
D.C. coupled to the input of one of the axes of two-dimensional analyzer. Another axis
is an energy spectrum of r -rays detected with a Ge (Li) detector. A block diagram isshown in Fig. 2. A time calibration is given by a multivibrator of which the frequency
is synchronized to a multiple of the triggering pulse frequency.
The chopper is placed just behind a slit of a beam course in the cyclotron facility,
and is used to search for isomers decaying with half-lives in the millisecond region.
Fig. 3 shows a typical spectrum of delayed r-rays from excited states 2.954 MeV(7 or 8-) in 132Xe excited by 130Te (a, n) reaction.
106( 7,8 )
(6,7,8)><lJ

177~~~ri538-""
I'-I'--( 5,6 )

-

204 1
601

4+
Cl)

-

(") 0
t.n<.JJ

1 440
773

Cl)

<.JJ
<.JJ

~ I I

2+

668

(")

668

I'-I'--

ot0

Prompt

<lJ

c:
c:
0

10 3

.c

U
<fl

c:
::J

0

U

10 2

10 1

10~L-----~------~~-----~------~2~0~O-Channel

Fig. 2.

numberGamma -ray spectra from the l30 Te (a, 2n)132Xe reaction. Prompt and delayed (from2.9 to 4.7 ms and from 16.4 to 18.2 ms)spectra are shown. The level scheme
shown is that proposed by Brinckmann etal. l )

74

Quadrupole
focusing Mog.

t il

DO .... .

LJ

Lamp

--------~----------------------------*--------BeamDO

Fig. 3.

Phototron sist~r

A schematic diagram of the beam chopping
system. The beam which passes throughthe chopper is guided to the target room.
The size of the beam on the target is controlled by a quadrupole focusing magnet.
The pulse from a photo -transistor isshaped and fed to the gate of a pulse generator to obtain a delayed pulse in the
millisecond region.

Reference
1)

H.F. Brinckmann, C. Heiser, and W.D. Fromm: Nucl. Phys., 96, 318 (1966).

75

6-3.

A Y-Ray Spectrometer for Nuclear Study

M. Okano, Y. Tendow, T. Katou,
K. Izumo, and T. Hamada

A standard r -ray spectrometer using semiconductor detectors has been
employed for the measurements of radiations accompanying nuclear reactions as wellas those from radioactive nuclides produced by the cyclotron.
Two commercially available solid-state detectors were used, one is a planar-type
Si (Li) detector for X -ray measurements (Princeton Gamma -Tech) having 10 mm diameter and about 3 mm depletion depth. The other is a coaxial-type Ge (Li) detector(ORTEC) with an active volume of 23.1 cm 3 . The guaranteed system resolutions ofthese detectors were 300 eV for 5.9 keY Fe K X -rays and 3 keY for 1332 keY 60Co
r -rays, respectively. These detectors were operated in conjunction with the NO 2200
sys tern multi -parameter pulse height analyser. The sys tern resolution and the relative
full energy peak efficiency were measured using several standard radioactive sources,
and the results are shown in Fig. 1. Recently, the preamplifier for the Ge (Li) detector,
ORTEC ll8A type, has been replaced by ORTEC 120F type to improve the resolution.
The Si (Li) detector was mainly used for the detection of atomic excitation X -rays
and of r -rays of energy lower than 100 keY. The Ge (Li) detector was equipped in a
10 cm thick lead cave together with an annular type 6 in X 6 in Na I (Tl) scintillator

:>.

u

c::

Q)

0.1

.Q

.....

"Q)

5

.:.:
0
Q)

->

n.
:>.

Q)

.:s:

~

-

Q)

c::

Q)

c::
0

~

4-

0.01

resol ution

~

0

en

Q)

Q)

>

a:

~

0.5

Q)

a:

Energ yFig. 1.

(MeV)

Relative full-energy peak efficiency andenergy resolution of the Si (Li) and Ge (Li)detectors as a function of photon energy.

76

Table 1.

Background counting rate of the Ge (Li) detector placed ina 10 cm thick lead shield at energy intervals of full energy
peaks of r -rays from various nuclides.

NuclidesEnergy(keV)

Background c oun tingrate without antiCompton gate (cpm)(during 40 h)

Background counting
r ate wi th anti -Compton
gate (cpm)(dur ing 65 h)annihilation
photon511

0.148 ± 0.011

0.027 -+ 0.004

Tl-208583

0.026 -+ 0.007

0.026 ± 0.007

Bi -214609

0.016 ± 0.006

0.030 -+ 0.004

Cs -137662

0.010 ± 0.006

0.011 ± 0.003

Ac-228908

0.013 -+ 0.005

0.011 -+ 0.003(Zn -65)(Bi -214)1115( 1120)0.021 ± 0.006

0.010 ± 0.002

K-40

1462

0.025 ± 0.005

0.044 ± 0.004

Bi -2141764

0.007 ± 0.003

0.005 -+ 0.002

Tl-2082614

0.007 ± 0.003

0.007 ± 0.002

(%)

2.0

lmm

1.0
,

6 mm

0 .8

0.6
l lmm
I

0.4

0'~3~---~2:-------71---~0 ----;---~
2 ------::!3cm

Fig. 2.

Absolute full energy peak efficiency of
the Ge (Li) detector for Cs -137 662
keY gamma -rays. Abscissa: radial
dis tance of the source from the detector axis. Parameter: vertical distance from the detector end cap.

77

split by halves, and the system is used as an anti-Compton or pair-spectrometer)
The Compton spectrometer reduces not only the Compton background but also thecosmic -ray background. The very low inherent background of the system was achievedby selecting the construction material of low radioactivity. Background counting rates
with and without anti -Compton gate are shown in Table 1. The absolute full energy
peak efficiency at 662 keY 137 Cs line as a function of radial distance of the source fromthe axis of the detector near the detector end cap, and that as a function of verticaldistance along the axis from the end cap are shown in Fig. 2 and in Table 2, respectively.
This spectrometer system enables us to make energy and intensity measurementsof X -rays and r - rays over an energy range from 2 ke V to several Me V and also to detect gamma -emitting nuclides of extremely low activity down to the order of pCL

Table 2.

Absolute full energy peak efficiency of the Ge (Li) detector
for Cs-137 662 keY r -ray as a function of distance fromsource to top of end c.ap.

Distance (mm)Efficiency (%)

1

1.21

2

1.08

5

0.87

10

0.61

20

0.344

50

0.123

100

0.044

200

0.0133500

0.00205

78

6- 4.

Data Processor

T. Wada, Y. Chiba, and F. Yoshida(1)

On -line PHA System

The interface 1} of two ADC units to the DDP -124 computer was improved to reduce the dead time. An one -word (24 bits) buffer-register was introduced and thecontents of it could be read into the accumulator directly. The 12 -bit data lines fromone ADC was connected to the lower 12 bits of the buffer -regis ter, and the other 12 -bi t
data lines to the upper 12 bits. Figure 1 shows the block diagram of this new system.
For simplicity, only the connection for AND mode (Interrupt will occur when two bufferfull flip-flops are set) is shown. In the real system there is a switch to change themode. There are four modes, each ADC single, OR and AND modes. For OR lTIode, one
more gated flip -flop is needed to gate/hold the buffer -full signal (8 in the figure). This
is not shown in the figure. The dead time of this system is (ADC dead tim e + 1. 5,asec),
when the average interval between input signals is longer than the processing time ofcomputer, program.
The computer program to write the address data from ADC on a magnetic tape
was made. This is useful for the identification of isotopes in the experiment of heavy
ion reaction.
(2)

Software

Many programs for the DDP -124 computer has been produced for four years.

r- - - - - - - - - - - - - - - - - - - - - - - - - - -,
I
I
I

12
bits

12 bits
gate
data

I
I
I

DDP
read

124

AOC
#1

i nterrupt------- ----- --------- - ,ackn owledge

Li8

~

ADC
#2

same

c,rcul t

I

I

I

I'-- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ JI

Fig. 1.

The block diagram of the new interface for
two ADCs to DDP-124 computer.

79

Their contents are variable. About 10 programs are produced for plotting, printing
and simple calculation of data of PHA system and so on. There are four programs
which calculate orbits of cyclotron or n1agnets. Using other progranls, we can calculate kinematics-, Q value, charge exchange, etc. There are also some programs forlisting, conversion and instruments test.

Reference
1)

T. Wada, Y. Chiba, K. Matsuda, and M. Yoshimizu : IPCR Cyclotron Progr. Rep.,~ 62 (1967).

80

7. RADIOCHEMISTRY
7- 1.

Chem ical Behavior of Carbon in Sem iconductor Siliconin the Dissolution and Fusion of the Matrix

T. Nozaki, Y. Yatsurugi, and N. Akiyama

Our study of carbon in semiconductor silicon has been continued for 4 years andsome results were reported already. 1)----6) Thus, the following is now known: (1) thesolubility of carbon in solid silicon is about 2.5 wt ppm at the melting pOint, and carbon
with a concentration higher than this value forms SiC precipitate; (2) most kinds ofcommercial semiconductor silicon contain from 50 ppb to 2 ppm of carbon; and (3)carbon dissolved in silicon occupies the substitutional site in the silicon crystal lattice.
In the present report, the chemical behavior of carbon in semiconductor silicon in
the dissolution and fusion of the matrix is described.
The lIe -tracer technique was used, with the nuclear reaction for the productionof lIe being IlB(p, n)lle. Three kinds of lIe-containing silicon samples wereprepared by the following methods. (1) A silicon wafer (3 cm diameter, 2 mm thickness) containing boron from 50 to 100 ppm was bombarded (13 MeV proton, a few JlA,
20 min), and then left for 40 min to allow the 30 p formed by the 30Si(p, n)30 p reaction
to decay out. (2) A B20 3 target was bombarded (13 MeV proton, about 10 JlA , severalmin) in a helium stream from a cylinder to a chemistry roon1. A noticeable portionof the llC formed was evolved into the stream as oxides and carried to th e chemistry. room, where it was caught in a liquid-nitrogen trap. A part of a small silicon rod
sustained in an evacuated Pyrex tube was fused by radio -frequency heating, and thelIe was introduced into the tube. After being kept molten for a few min, the silicon
was left to cool, and then its surface was removed by etching. (3) The process was
similar to that in (2), but the silicon melt was brought into contact with a small quantityof graphite powder or with gaseous carbon oxide. The lIe atom in the sample preparedin alka li solution ( NaOH, NaOH-NaN0 3 or N020 2 )K Mn 04,
Boil }
H2S0 4

I 20'" 80 I

lHF. Boi!

KMn04
or Cr03 J
Bo il

Si02 powder,
Centr ifuge

I

)951

Remove theprecipitate@]
Fig. 1.

Behavior of homogeneously dispersed lIe __fraction of lIe remaining( %).

81

by Method 1 can occupy a higher-energy site in the silicon crystal, because it wasprovided with the nuclear recoil energy at its nascent stage. The samples given by
Methods 1 and 2 contain carbon homogeneously dispersed atomistically, but the SiC
precipitate is present in the sample obtained by Method 3.
After the measurement of radioactivity, the sample was decomposed by thefollowing treatments : (1) dissolution in an alkaline solution, (2) dissolution in a HFHN0 3 solution, (3) alkali fusion with NaOH, and (4) acidic fusion with Pb 30 4 -&~03'
Then, the product was treated with various reagents, and the behavior of the 1 C was
examined. The quantity of the reagent used was at least 50 % excess in all cases.
The results are shown in Figs. 1, 2, and 3. No difference was observed in the
behavior of liC between the sample prepared by Method 1 and that prepared by Method
2. From Figs. 1 and 2, the carbon homogeneously dispersed is found to behave quite
similarly to elementary carbon in minute grains. In the acidification of the alkaline
Fuse

with

Fuse with~~~~__P~b3~O~4_-__B~
2 0_3____~

NoOH- No N03~----- (Sample

J--------,
Fuse with

Oi ss olve inOisso Ive

HF - HN03

In

NoOH

HF - H N0 3- KI0 4

KMn04 ,BoilFig. 2.

Behavior of homogeneously dispersed llC fraction of llC remaining ( %) .

( Sample J

Fuse with
Pb3 04 - 8 2 °3I

Disso\ve in
HF-HN03 - KI04

~n04

1

Boil

I 60 I!

NaOH ,80"\,

H2 S0 4I

Fig. 3.

50

Behaviour of coagulated
llC remaining ( %) .

I

11

C-

fraction of

82

solution, it is quite probable that hydrated silicon oxide is precipitated embracing
almost the entire part of the carbon.
Table 1 indicates the sensibility of the three analytical methods to the homogeneously dispersed carbon and to the SiC precipitate. The fraction of carbon in SiC
determined as carbon in the second lnethod in Table 1 is dependent on the degre e ofcoagulation of the SiC precipitate. Therefore, by the use of the three methods inTable 1, it is possible, though high accuracies are needed in the determination, to get
information about the dispersion state of carbon in silicon.
Table 1.

Sensibility of the three methods to the different
physical states of Carbon in silicon.

MethodInfrared spectrophotornetry

Activation
analysis

Homogeneously
dispersed carbon

Coagulated
carbon+

HF-HN03-KI04-KMn04
dissolution++

Pb304 -B203 fusion(or nondestructive)++

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

T. Nozaki, Y. Yatsurugi, and N. Akiyama
J. Radioanal. Chern. , .!, 87 (1970).
T. Nozaki, Y. Yatsurugi, and N. Akiyama
J. Electrochem. Soc., 117, 1566
(1970).
T. Nozaki, Y. Makide, Y. Yatsurugi, N. Akiyama, and Y. Endo: Int. J. Appl.
Radiat. Isotopes, 22, 607 (1971).
T. Nozaki: IPCR Cyclotron Progr. Rep., l.. 66 (1967).
T. Nozaki, Y. Yatsurugi, and N. Akiyama
ibid.,~ 121 (1968).
T. Nozaki, Y. Yatsurugi, and N. Akiyama: ibid., 3, 88 (1969),

83

7-2.

Excitation Function for Some Triton-induced

ReactionsT. Nozaki, M. Okano,
M. Furukawa, S. Kume, and R. Seki

The excitation functions for the reactions of 27 Al(t,2p)28 Mg , 26 Mg(t,p)28 Mg ,Si + t--+ 28 Mg, Al + t_24Na, Si + t-24Na, and 160(t,n) 18F were rneasured up to the triton energy of 23 MeV. The stack foil method was used, the target stack for aluminum,magnesium, silicon, and oxygen being of a luminum foil (about 25 111g / crn 2 ), magnesiUlTI
foil (15 to 20 mg/cm 2 ) or vacuum -s ublimated 111agnesium (about 1 mg /c m 2 ) on tantalUlTI
foil, silicon wafers (about 60 mg/cm 2 ), and quartz plates, respectively. The induced radioactivity was lTIeasured by a Ge(Li) detector and a NaI detector of calibrated efficiencies.
The r es ults are shown in Figs. 1, 2, and 3. Their cross s e ctions are for thetarget substances of the natural isotopk c0111poSi tion. The unc erta inty in the absolute
cross section can be regarded as 15 % for all the reactions except for the reac tion of

0 .1

10

.D

E

-

c
0
U
<lJ

V>

.0

E

V>

0
L

U

/l

II>
V>

0.0

f:

o

U

10

Tr i ton

Fig. 1.

!
energy

20

o

(MeV)

Excitation functions for ther eac tions of AI+l -~28Mg ,Al + t -~24Na, and Mg + t --+28Mg.

Fig. 2.

20

10
Tr i ton energy( MeV )Exci ta tion functions for thereactions of Si+t _~28Mg
Clnd Si +t -~ 24Na.

84

1000

500

.0

E
co
o

~ 100
V>
V>

o

U

50

o

10
TritonFig. 3.

energy20( MeV )Exci tation function for thereaction of O+t _18 F .
(The dotted line region is
given in Ref. 1 »160(t, n) 18F. The excitation function for this reaction has a fairly sharp peak in the
low-energy region; thus, the precise measurement of the maximum cross section
and the peak shape requires a more elaborate work with thinner target plates.

Reference
1)

P. E. Wilkniss and H. J. Born

Int. J. Appl. Radiat. Isotopes,..!.§., 59 (1967).

85

7-3.

A Mossbauer Spectroscopic Study of Chemical States of 119S n
after EC Decay of 119Sb in Antimony Chalcogenides

F. Ambe, H. Shoji*, S. Ambe, M. Takada**, and N. Saito

Measurement of the Mossbauer emission spectra gives valuable information
concerning the after-effect of nuclear decay as well as concerning the chemical
behaviour of atoms in a dilute solid solution. We have been studying application of
119Sn-Mbssbauer emission spectroscopy, using cyclotron-produced 119 Sb (38.0 h) and
119m·Te (4.7 days) as source nuclides. Here we will report the results recently obtained on antimony chalcogenides. A partial description of the experiments has alreadybeen made. 1)
The 119 Sb and 119 m Te were produced by the p-, d-, or a- irradiation of a tin
plate with a natural isotopic abundance. The source nuclides were separated front
the tin target by radiochemical procedures consisting of solvent extraction, ion exchange, and precipitation. Antimo ny chalcogenides labelled with the nuclides wereprepared by well-established methods reported in the literature. The ll9Sn-Mossbauer
emission spectra were measured with the labelled compounds as the source at liquid
nitrogen temperature against a bariu111 stannate standard absorber. In Table 1 aresummarized the Mbssbauer parameters derived from the observed emission spectraby least -squares computer fitting. The values of the isol1ter shift versus barium
stannate are shown in the Table , the sign being as in usual absorption spectra.

Table 1.

Sourcecompounds

IS0111 er shift

119 Sb 0
2 3

3.2

119Sb S
2 3

3.8(mm / sec)

Quadrupole
splitting(mm / sec)

Assignedvalence

1.B

Sn (II)

1.4

Sn (II)Sn (IV)

119Sb Se
2 3

3.7
1.7

Sn (II)Sn (IV)

119 Sb2 Te

3.4

Sn ( II)3

Sb 119n1 Te
2
3

*
**

119Sn-Mdssbauer para111eters of the emission
spectra in antintony chalcogenides.

2.6

Visitor from Tokyo University of Education.
Visitor from the University of Tokyo.

0.6

86

Antimony trioxide in the cubic form was prepared by hydrolysis of a solution oftrivalent antimony and sublimation of the product in a vacuum. Its emission spectra
consisted of a doublet, which may be assigned to the divalent state of tin on the basisof the data of the absorption spectra of tin oxides.
For antimony trisulfide, measurements were made on samples in the crystalline
black form prepared by three different methods. In the wet method, the sample inthe crystalline form was prepared by heating the amorphous orange sulfide in dilutehydrochloric acid and then drying the product over phosphorus pentoxide in a vacuum.
The emission spectrum of this sam ple is shown at the top of Fig. 1. In the Henz
method, 2) shown in the middle of the figure, amorphous sulfide was heated in an argon
atmosphere in order to obtain the crystalline form. In the last method , the crystalline
sulfide prepared by the Henz method was sublimed in a vacuum. As can be seen in
Fig. 1, the emission spectra of the sulfides consisted of two emission peaks, one
corresponding to the divalent state of tin, and the other to the tetravalent state of tin,
their isomer shifts being almost independent of the method of preparation. The most'striking finding with regard to this compound is the change in the intensity ratio thetwo peaks as the method of preparation is changed. Further experiments are in
progress to find out the factors influencing the intensity ratio.
Antimony selenide and telluride were prepared by fusing a stoichiometric mixtrueof antimony and selenium or tellurium in an argon atmosphere. Antimony selenide
gave two emission peaks which can be assigned to the divalent and tetravalent states oftin, as in the case of sulfide. In this compound , however , the ratio of intensity of thetwo peaks was not reproducible, even for the samples prepared by the same method.

5100-1
100

97
;>..

:=
(f)

5132 -1

c
(l)

+-'

c

OO C

100

co

~
00

J

(l)

,~
+-'
0

(l)

a::

98
5201-1
100

98
SnS

U

Sn S2

Re i'Jti ve ve locity (mm/sec)

Fig . 1.

119Sn -Mossbauer emission spectra inantimony trisulfides.

875082- 1100
975219-1
Q)>

100.....oQ)a:99

Re lative velocity (mm/sec)' 2
P Ig..

'
119S n - M"oss b auer emIssion
spectra inantimony tellurides.

Por antimony telluride, a comparative study of novel type was made taking advantage of the fact that 119Sb can be incorporated in the lattice of this compound in two
different ways, directly as 119Sb in the antimony site (119Sb2Te3) or as the decay
product of 119 m Te labelled in the tellurium site (Sb2119mTe3)' As can been seen in
Pig. 2, a clear difference was observed between the emission spectra of the two typesof labelled compounds, 119Sb2Te3 and Sb2119mTe3. 119Sb2Te3 gave a single line peakwith an isomer shift very close to that of tin telluride, while Sb2119mTe3 gave a broad
emission peak with an isomer shift of 2.6 mm/sec, showing that the s -electron density
at the tin nucleus is smaller in this case than in 119 Sb 2 Te3' In Table 1 is shown thevalue of quadrupole splitting computed on the assumption that the peak is an unresolved
symmetric doublet due to a quadrupolar hyperfine interaction of the 119 Sn nucleus.

References
1)
2)

P. Ambe, H. Shoji, S. Ambe, M. Takeda, and N. Saito
Rep. ,..it 115 (1970).
P. Henz: Z. Anorg. Chern., 37, 18 (1903).

IPCR Cyclotron Progr.

88

7 -4.

Charge States of Ions Produced by the Decay of 18F

S. Yokoi *, M. Aratani, and T. Nozaki

Measurements have been made on the charge distribution of the ions produced by
the decay of 18 p (100 In) trapped on the metal plates. The apparatus employed was
the same as previously reported. 1) It was a magnetic spectrometer with an ion det ectorof a pulse -counting mode.
The radionuclide, 18 p , was produced by the 16 0 ( 3 He , p) 18 p nuclear reaction.
An oxygen strean1 was bombarded in a vessel designed for cyc lotron bombardrnent by
3He particles (14 '""-- 15 MeV).2) i\!letal plates of 0.5 X 10 X 20 mm were dried after
surface cleaning and placed for expos ing to the oombarded gas stream at the outlet ofth e vessel. A part of the 18p formed in the gas stream was trapped on the surfaces ofthe metal plates.
The n1easurement of the half -life of the radioactivity on the metal plates showedthat it consisted only of 18 p . The counting rates of the metal plates were measured
by means of a sc intillat ion counter.
It was' s hown that the lSp on the metal plates was easily removed by washing ina water flow. For example , the counting rates for Ag and Cu plates decreased to :),:3 ~0
and 4 .S % respectively after washing. On the other hand. it was s hown that the J SF on
th e metal plates was not removed by vac uum ex haust ion. Prom these results. it was
deduced that a major part of the lSF was attac h ed by c h em i sorpt ion on the surface ofth e metal plates.

1. Rota ry pump

IJ

Detecto r si l t

14Electron mul t ipli er

15

Preamp lif Ier

16

Ampll fe r

Aut omat ic valve

17 Sc al er

3 Diffu Sion pump

18 Prin t er

2
4

I oni zat io n gauge

5 Hand va Ive

6.

on sou rce

7. Gr ounded sli t

86

F ig . L.

*

Present address

Ion deflect i on plate9

Foc al si lto.

Anal yzer tube

1 1.

Analyzer magnet

12 .

Gate valve

C h(]rgc spectrometer for sol id rudioisotopes.

Ota Pharmaceutical Co., Kawaguchi, Saitalna Prefecture, Japan.

89

A metal plate with 18 p was employed as the ion source of the spectrometer.
The ion-expelling voltage was 4500 -- 5000 V. The metal exposed to the bombarded gas
stream was immediately mounted in the ion-source chamber of the spectrometer, andthe apparatus was exhausted to 2 X 10--6 Torr. When the ion-expelling voltage wasapplied, the 18 p on the metal plate behaved as a puls ~d-ion emitter due to its decay.
The ions produced by the decay of the 18 p on the metal surface were expelled througha grounded slit with stainless steel meshes, analyzed by the magnetic field, and counted
by a 16-stage Cu-Be electron multiplier.
The charge distribution of the atoms produced by the decay of the 18 p on the Cu
plate was as follows: Singly-charged ion, 9.5; +2-charged ion, 1.0; +3-charged ion,
1.4; +4-charged ion, 2.5; +5-charged ion, 2.8 ; +6-charged ion , 4.0. In this range
the ion yields increased with a decreas e in the number of 2s and 2p electrons of the(ls)2 (2s)2 (2p)4 of 18 0 with the exception of the singly-charged ion. The yields ofboth the +7 - and +8 -charged ions were less than that of the +6 -charged ion in every
run, although the values fluctuated. The positron decay of 18 p and the inner-shellionization of the 18 0 formed from 18 p may be responsible for this type of charge
distribution.

References
1)
2)

M. Aratani and N. Saito: Mass Spectros., lli 906 (1970).
T. Nozaki, Y. Tanaka, A. Shimamura, and T. Karasawa: Int. J. AppL
Radiat. Isotopes, 19,27 (1968).

90

8.

RADIATION CHEMISTRY AND RADIATION BIOLOGY

8- 1.

Rod io Iys is of Ket ones i n H ig h LET Reg ion
M. Matsui, M. Imamura, and T. Karasawa

In the systematic studies of the LET effects on the radiolysis of liquid organic
compounds, some ketones were subjected to the study using heavy -ion beams.
Ketones used were acetone, methyl-ethyl ketone, and diethyl ketone. Heavy ionswere 12C of 53.5 MeV and 14N of 22.4 --- 68.0 MeV; instantaneous LET -values of theseoions were 29 and 32-----61 eV / A, respectively. Experimental procedures have been
described previously.l),2)In this report, the results with diethyl ketone are described. The radiolytic
gaseous products from diethyl ketone are H2 and CO as principal products and saturated and unsaturated C 1 -C4 hydrocarbons as minor products. Th ese products were
determined gaschromatographically using silica gel-A1203 and Molecular Sieve SA
columns. Great care was taken for collecting the hydrocarbons produced frOln
irradiated samples.
The yields (G) of H2 and CO are plotted as a function of the energy-loss parameterof radiation defined by z = (l / Es) f~s (-dE / dx) dE in Fig. 1. (Es is the energy of ionsenteri ng solution; -dE / dx is LET). The yields of hydrocarbons are summariz ed inTable 1. These data include the results for 60Co - r- and a -radio lyses. In th e radiolyses with r - and a -radiations , samples contained iodine of about 7 X lO-3 M , which
serves as a radical scavenger. This means that the G-valu es for r - and O'-radiolyses
represent the so -called molecular yields; in the heavy -ion radio lysi s, all the yields
can be regarded as molecular ones.

5

I

/\

4

,

3

H2

~

2

o

~_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_--------~..

•

0

10- 2

10 - 1

/

1\

:.~,

co

1

z

Fig. 1.

..,

1\

<..cl

( eV/A )Variations with LET (stopping-power parameter, z) of the yieldsof H2 ( 0 ) and CO (e) in the radiolysis of liquid diethyl ketone.
Maximum G (H2) and G (CO) appear to be expected at z = 40
o
eV/A.

91

Table 1.

[I2]

Radiolysis yields of hydrocarbons.

M

LET0(eV / A)'-CH

4

60 co - r-----7 X 10-3

0.02

4 He

-----7 X 10-3

Radiation

14N

0

C 2H6

G- V<illues
C 2H 2C 2 H4C 3HS

n-C 4 H 10'

0.05

0.23

0.46

0.05

0.02

0.15

3~4

0.06

0.26

0.49

0.09

0.03

0.16

61.2

0.31

0.69

1.2

0.52

0.17

0.42

The important features of the experimental results are summarized as follows:(1)
As shown in Fig. 1, G(H2) and G(CO) increase slowly from nearly 1 as LEToincreases in the region less than 10 eV / A and then a steep increase takes place. Theoboth yields seem to reach their maximum values in the vicinity of 40 eV / A and thendrop at higher LETs'. The yields of some hydrocarbons also appear to show similar
behavior.
(2)
The ratio of G(H2) to G(CO) increases as LET increases: 1.1, 1.3, and
1.6'""-'1.S for r-, a -, and heavy-ion radiolyses, respectively.
(3)
The increase in G(C2H2) with increase of LET is outstanding among increasing yields of hydrocarbons.
The slow increases of the molecular yields of H2 and CO at LETs' less than 10oeV / A may be explained on the basis of a simple diffusion -kinetics model. The steep
increases in the higher LET region cannot be accounted for unless some contributionof the thermal spikes in the dense ionization tracks is assumed.
Although a definite evidence of the thermal-spike eft ects in the high - LET radiation
tracks has not been demonstrated in liquid -phase radiolysis, the present results seem
to offer a support for this hypothesis. The ratio, G(H 2 )/G(CO), increases with increasing LET from 1.1 for r-rays to 1.6-----1.8 for heavy ions. One molecule of CO
should be produced from one molecule of ketone, and H2 from alkyl radicals. If thethermal decomposition of alkyl radicals is assumed to be accelerated in the dense
tracks where local temperature increase is sustained during the reactions, one could
expect the simultaneous increases in the yields of H2 and unsaturated hydrocarbons.
The increases in the yields of unsaturated hydrocarbons were also demonstrated
by the experiments on the laser irradiation of diethy I ketone vapor, in which keton emolecules are believed to decompose thermally.
o
The steep decreases in the yields observed above 40 eV / A is of great interest,a similar phenomenon has, to the authors' knowledge, not yet been reported. Insofar as
the radiation track with a fixed radius is assumed, initial concentrations of excitedmolecules or radicals formed under the present conditions should exceed the orginal
concentration of molecules confined in the track. This may result in the waste of energy
endowed from radiations and in the apparent lowering of the yields in the very high LET
region.
Similar phenomenon has also been observed in acetone and methyl-ethyl ketone
and further studies are in progress.
.

92

References
1)

M. Imamura, M. Matsui, and T. Karasawa: IPCR Cyclotron Progr. Rep.,.i,
119 (1970).

2)

M. Imamura, M. Matsui, and T. Karasawa: Bull. Chern. Soc. Japan, 43,2745 (1979).

93

8-2.

LET EffectIn

the Rediolysis of Some Organic Liquids

M. Matsui and M. Imamura

The LET effect on the radiolysis yields from various compounds has been a longterm subject in the radiation chemistry. However, owing to the limitationof the radiao
tions available, the range of LET has scarcely exceeded 20------30 eV / A. Uranium fission
fragments have an extraordinarily high LET, but they are always confronted with someinevitable complexities.
We have been employing heavy ions, 12C and 14 N, ac celerated with the cyclotron
to investigate the radiolysis of some organic liquids in the very high LET region. Herewe wish to review these results along with a few results by other workers and discuss
the general features of the LET effect. In addition to the usual diffusion-kinetics th eory,some other factors seem to be required to explain the phenom e na observed in the very
high LET region.
The results are summarized in Figs. 1 and 2, wh ere the results with be nze ne andcyclohexane obtained by Schuler 1 ) and Burns et al. 2) are also included. These figur es
show variations of the yields of only H2' the principal gaseous product, as a [unction of
the stopping-power parameter, z.
As is seen from Figs. 1 and 2, G(H2)-values of cyclohexane and m ethanol show

10

8

N

6

:r:
(::J

4 -

\ etroh~dro\\Jron1\

2

Benzene010 - 2

10- \

10

10 3

z ( eV / A)

Fig. 1.

Voriatton of G (H2) with L ET (stoppingpower param eter, z) for m et hanol andcyclohcxane.

94

8~----~----~------~----~----~

6
N

I

4

210- 210103

z ( eV / A)

Fig. 2.

Variation of G (H 2 ) with LET(stopping -power parameter, z)
for tetrahydrofuran, diethyl
ketone, and benzene.
otheir minima in the vicinity of 10 eV / A, whereas those of tetrahydrofuran, diethyl
ketone, and benzene do not. The former compounds have relatively large radical yields
in the r -radiolysis and the latters have low ones.
For methanol, the r -yield of solvated electrons has been found to be 2 in G -unit 3 )and to decrease with increasing LET. On the basis that the yield of the total ionization
in methanol is invariant irrespective of the nature of radiations, the probability ofrecapturing electrons by positively -charged species in spurs or tracks increases withincreasing LET. The recombination has been assumed to give rise to the formation of
H-atoms and/or H2 molecules. The gradual decrease in G(H 2 ) for methanol cannot be
explained by assuming that every recombination of electron produced the excited state,
the precursor of H or H 2 . Therefore, it is likely to consider that some parts of excitedstates thus produced may be deactivated without forming H or H2.
The LET effect in cyclohexane, according to Burns,2) has been interpreted by
the competition of excited molecules. This model, in which LET effects are due toevents prior to radical formation, is more successful than the radical model in the LETorange less than 10 eV / A.
On the other hand, in tetrahydrofuran, diethyl ketone, and benzene, most of H2
are formed molecularly, Le., in spurs or tracks. Therefore, the variations of G(H2)owith LET below 10 eV / A may beoaccounted for by the usual diffusion -kinetics model.
Above several tens of eV / A, H2 may be regarded to be produced by quite different
modes as stated in the preceding section. In the high LET region, increases in G(H 2)
are observed for all compounds irrespective of the different behavior at lower LETs' .
This similar dependence with LET may imply an important contribution of thermal
spikes which accelerates the decomposition of free radicals. Recently, Voltz 4 ) observed the opposite variations of radiation-induced luminescence and G(H2) for toluenein the high LET region. He suggested that this effect may arise from the interactionof transient excited intermediates.
References
1)
2)
3)
4)

R. H. Schuler: Trans. Faraday Soc., 21., 100 (1965).
W. G. Burns and C. R. V. Reed: ibid., 66, 2159 (1970).
H. Seki and M. Imamura: J. Phys. Chern., 7J, 870 (1967).
R. Voltz: Proc. Intern. Discussion on Progress and Problems in Contemporary
Radiation Chemistry, Prague, p. 45 (1971).

95

8-3.

LET Effects on Bacterial Cells

A. Matsuyama, T. Karasawa, T. Takahashi , and F. Masuda(1)

L ET effects on cellular radiosensitivities of bacteria

Determinations of relative biological effectiveness (RBE) of different particles
accelerated in the cyclotron for the induction of cell death in bacterial cells are stillin progress. Bacterial strains used in thi s study were E. coli BS -1 and B/r, M. radiodurans, B. subtilis 168 thymine- requiring mutant and its spores. Vegetative cells were
harvested during the log-phase of the bacterial culture and washed with 0. 067 M phos'phate buffer. As previously described , l) a monolayer of bacterial cells prepared on
a Millipore filter (type HA, 9 mm in diameter) which had been placed on a wet filter pad
was irradiated with charged particles such as protons, a -particles, carbon - , nitrogen -,and oxygen -ions in air at room temperature. Two sets of experimental results obtained
Iwith ] E. coli Bs -1 and B. subtilis spores are shown in Fig. 1.
The results indicate that the RBE largely varies with different LETs and types ofionizing particles. For all strains, the RBE of different particles were found to bedifferent at the same total LET (Loo). The I/D37 value as a measure of RBE increasedin the increasing order of a-particles , carbon- , nitrogen-,and oxygen-ions at the same
Loo. This increase in RBE observed in the energy range higher than unity in MeV per
B Subtilis

168 t hy- in d- le u( MY2 YI U2) spor eE. col i 8s- 1

1.00

O'(o3) ~

~
____

0.50

<;>

0

O'(O. ~
<t

0.10

o

00

o

<;>

-

N~

c
~

- 0.05

N~

o

0.10

c

a

~ 0 .05~ 1.00. ~ 0.50a>u~ 0.0 1"--------::c'---------'-------'h--~

0.1

0.1

<f>
<f>

a

u

~ 0.10

o

0.0 5

10

(102)

CX---1] 0.06

04

~004

-0

'-

'-

-

- --!-------rf-----------,Jl'0==<-- - - - - - . - c
1O~O;-;-(e~VI A)

o

r--

'-

cry

0

0.Q1 L---~O .-:-'-

100 (eV/A)

0 .6

-,

N--.o1(23 4 ) C

(23.4)
0'---10°1ik8)

¥

<;>

00 5

~

~(154)o~ 0.01-10 (M eV /o mu )0 .2
0Fig. 1.

=

0.02
0 "-----~
0.-,---~----7~--~~oRadiosensitivity and inactivation cross section as a function of Loo(eV IA)
or energy per nucleon (MeV I amu).

96

atomic mass unit (amu) can be explained by the 0 -ray effect as described below.
The inactivation cross section for ionizing particles was estimated in cases offour strains which gave an exponential-type survival curve, except M. radiodurans.
For a -particles, the inactivation cross section increased in the very lower energy
region and then showed a remarkable decrease in the region more than 1 MeV lamu.
The maximum value/of the inactivation cross section for a -particles was found in casesof all four types of bacteria at the same energy (0.3 MeV lamu) which gave the maximumo
Loo in water (23.4 eV I A). The value of the maximum inactivation cross section fora -particles was found to be smaller than the projected area of a nuclear body inbacterial cells observed by electron microscopy and it appeared to depend upon thecapacity of the DNA repair.
In the relationship between Loo and I/D37, a peak of the curve representing thisrelationship was observed at around 6 eV I A with E. coli B/r depending upon the ageof the bacterial culture. This fact may indicate that the two -hit model is required tointerpret the occurrence of this peak from a viewpoint of the target theory. Further
determinations in the very low energy range (less than unity in MeV lamu) are now
undertaken for heavy ions.
In the case of M. radiodurans, 2) the shoulder dose and D 10 value for the exponential slope of a sigmoidal survival curve were similarly decreased at high LET.
(2)

Analysis of data obtained with E. coli Bs-1

According to Dolphin and Hutchinson,3) the inactivation cross section S can be
repres ented by
S = So+fL/JV

FE

where S is the effective area of the target, f the fraction of energy dissipated by 0electron~ which depends upon cut -off energy W, L the total LET for the medium of/J = 1, /J the density of the medium, V the sensitive volume of the target molecule, l/F
the overlapping factor for the 0 -electrons, and E the energy per primary ionization( E = 72 eV).

~

-

0 .8

c:

30.7
u

~ 0.6
II>
II>

o

t; 0.5
c:

0

.~

~ 0.4

o

.......
u

o

CJ

..s
Energyofparticles(MeV lamu)

o a-particles, () Carbon ions, • Nitrogen ions, 6 Oxygen ions
Real lines indicate the calculated curves for carbon ions (C) andni trogen ions (N).
Fig. 2.

Inactivation cross section of E. coli Bs -1 as a function of energy per
nucleon.

97

The observed inactivation cross section was fairly well represented when thefollowing constants and values of parameters were adopted (Fig. 2) : W = 2.75 keY,
fJ = 1.71, V = 3.8 X 10-3 IJ,3, c = 72 eV, l/F = 1/14.0. The adopted value for theoverlapping factor was less than that found for 60Co r -rays (1 /F = 1/5.9).

References
1)
2)
3)

A. Matsuyarna, T. Karasawa, S. Kitayarna, and R. Takeshita: IPeR Cyclotron
Progr. Rep., l.., 101 (1969).
F. Suhadi, S. Kitayama, Y. Okazawa, and A. Matsuyarna : Agr. BioI. Chern.,
35, 1644 (1971); Radiat. Res., 49, No. 1(1972)
C. W. Dolphin and F. Hutchinson: Radiat. Res., rr, 403 (1960).

98

9. SOLID STATE PHYSICS

9-1.

Electron Microscopic Observation on Helium Bubbles
In Aluminum Irradiated by Alpha-Particles

H. Sakairi, E. Yagi, H. Shiraishi,
T. Karasawa, and R. R. Hasiguti
Observation on He bubbles in aluminum irradiated by alpha-particles is being
continued. The method of He injection was improved so that the He ato·ms were distributed nearly uniformly in the specimens. The results obtained by the new method
were different front those of the previous ones, that is, the size of the bubbles became
smaller and the temperature for the bubble formation higher. Reasons for these havenot been clarified.
The average size and the density of observable bubbles in each specirnen arelisted in Table 1. The helium contents calculated are also presented and comparedwith those calculated from the irradiation dose. Both values agree in an order ofrnagni tude.
Fine bubbles and gross bubbles can appear in the grains and along the dislocations
and on the grain boundaries. Some correlations exist between the various appearancesof bubbles, which can been seen from Table 2.
Table 1.

Calculation of the average bubble diameter and the bubble density .
Helium content was derived from these data. Last column shows thetotal number of the bubbles used for the calculation.
Calculated
He cant.
(ppm)

Nb

4.9

34

337

157

2.0

16

138

1

183

3.0

29

408

600

1

1650

0.024

18

93

0

600

3

692

0.23

38

304

43

0

600

3

4140

0.010

49

36

43

0

600

100

168

2.8

16

145

43

0

645

1

167

2.4

19

182

43

0

645

1

142

4.8

27

653

43

0

645

1

814

0.22

39

69

Heat treatment

Implant. He

Cold work

Aver. dia.

Density

(ppm)

( %)

(oC)

( h)

(A)

0

( 10 13 cm -3)

43

0

550

100

142

43

0

600

1

43

0

600

43

0

43

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

87

0

550

87

0

600

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

1

70

1

99

-- -- - - ------- --~- ---- -

6.0

11

198

9.8

34

1136

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

43

8

600

1

180

0.71

7

35

43

8

645

1.5

591

0.23

24

308

( %)

0

0

8

(ppm)

43

87

43

2
4
1
3
1
2
3
1
2
1
1
2

1
1
100
1
3
100
1
1
1
10
100
1.5
1
1
1
10
1.5

500
550
550
~ 600
600
600
645

550
600
600
600
645

500
550
600
600
645

~

2
3
4
1
1

Speci.

(h)

(oC)

{

N.of*

Heat trea tment

0
19
11
0
27
0
0
2
4
0

17
29
70
18
28

0
0
6
28
0
5
15

0
0
0
1
6

0
2
0
26
4

1
3
0
22
11
1
12

(A)***
Matrix
~
Fine
Gross

22
35
22
33
47

13
32
10
82
24
32
39

Photo.

N. of**

1
0
0
0
0

0
2
6
0
17

2
4
8

6

0
0
0

0
0
0
0
3

0
2
0
10
2

0
0
0
9
0
0
0

(B)****
Dislocation,.--A-------...
Fine
Gross

0
0
0
0
0

0
0
2
0
5

0
0
2
0
0
1
0

0
0
0
0
5

0
0
0
18
0

0
0
0
6
7
0
3

(C)*****
Bouq.dary
F'ine
Gross

*****

****

this type seem to be very fine . The column under "Gross" shows the number of the photographs in which random distribution of gross helium bubbles was observed
within the grain .
The column under "Fine" shows the number of the lines of helium bubbles arranged in a row. The column under "Gross" shows the total number of the dislocations
on which the bubbles larger than in the grain interior were located.
The column under "Fine" shows the number of the total number of grain boundaries on which those bubbles were located, the size of which was roughly the same as
those distributed randomly in the grain interior. The column under "Gross" shows the total number of grain boundaries on which the bubbles larger than in the graininterior were loca ted.

* The number of the specimens observed.
** The number of the photographs taken .
*** The column under "Fine" shows the number of the photographs in which the homogeneous nucleation of helium bubbles within the grain was observed. Bubbles ofTensionFrequency of the bubble formation in the matrix and on some defects for the various treatments of the samples.

He cont.

Table 2.

'-0
'-0

100

The characteristic features of the bubbling are summarized as follows:(1)
No bubble appears unless the annealing temperature reaches 550°C.
This temperature is rather high compared with that for AI-Li alloys irradiated by pile
neutrons.
(2)
The bubbles are divided into two groups, fine bubbles and gross ones. The
absence of bubbles of an intermediate diameter does not occur in AI-Li alloys.
(3)
There are almost no gross bubbles in the sample in which many fine bubbles
appear and vice versa. Especially in the sample in which no fine bubble can be foundin the grain interior, many gross bubbles appear on the grain boundaries. In both cases,
He content which is calculated from observed diameter and density of bubbles agree
roughly with the content of injected He.
(4)
In some samples the fine bubbles can survive with a density of 1013cm-3
near the melting temperature.
(5)
When the He content is increased, the density of the bubbles increased but
their diameter is left unchanged or slightly decreases.
(6)
In the samples which are strained after the He inj ection, there are few finebubbles, especially around the sub-boundary dislocation network. This tendency isprominent in the samples which are heat -treated near the melting temperature.
Under normal conditions the bubbles in a grain interior cannot grow exceeding° in diameter. As the content of He contributing to the bubble formation is estimated200A
to be nearly equal to that of the injected He, it is evident that the growth must be stopped
by the exhaustion of He in the matrix. Under these circumstances some mechanisms,
such as random drift of the bubbles leading to the coalescence of them, must operate
for further growth of the bubbles. There are some examples, however , that the finebubbles can present stably near the melting temperature. Therefore we must consider
that the random drift of bubbles does not occur under usual conditions and that theformation of the gross bubbles are helped by another mechanism.
It is remarkable in the samples strained plastically, that many gross bubbles
can be found on the grain boundaries when there is no fine bubble in the grain interior.
It is naturally considered that the fine bubbles are swept away by the migration of grainboundaries or dislocations.
Several examples that the fine bubbles form a line with no dislocation, suggestthat an interaction between the bubbles and the dislocations is not strong. Such linesof bubbles should be a trace of the dislocation, by which the bubbles could once bepulled when they were finer.
There are also the examples of gross bubbles which are condidered to be left
behing by the migrating grain boundaries. It can be said that the pinning of the dislocations and the boundaries by the bubbles is not strong in pure aluminum.

101

9-2.

Point Defects

In

Irradiated Copper and CU3Au

H. Sakairi, E. Yagi, A. Koyama,
T. Karasawa, and :R.R. Hasiguti

In the irradiation experiments · of metals, the physical properties of pure metals
are not affected by atomic exchange replacements, while those of ordered alloys arechanged drastically because of the change of the degree of order induced by atomic exchange replacements. The irradiation study of ordered alloys, therefore, is expected
to give additional information which cannot be obtained by the studies of pure metals.
In a previous report 1) two important experimental results were described that (1)about ten times larger resistivity is introduced by irradiation in the ordered coppergold alloy as compared with that introduced in copper, and (2) the resistivity change ofthe ordered alloy is far larger than that of copper in the stage III annealing. * It is considered that the kind and the concentration of lattice defects brought about under thesame irradiation conditions are nearly the same both in the alloy and copper. Thismeans that the large differences in the irradiation induced resistivity and its change instage III described above are due to the changes in the degree of order in the alloy. In
this report the damage introduction rates precisely determined are presented and on
the basis of these the nature of the stage I, II, and III defects are discussed.

• Liq. Heo Liq . N2-:::::-%,622

10- 23~, 0- 23

10- 24........

Q)

v

~
L

0

a.
........

E
'-?
E

~

~

L
Q)

0'

0

E
0

0

Total energy transfered per particle (eYlcm 3 . particle)

Fig. 1.

Damage rate at Liq. He and Liq. N2 temperature.

* The lab e lling of stages will be made as follows:

0stage I below 70 K, stage II be0
tween 70 ° and 220 K, and stage III between 220° and 300 0 K.

102Figure 1 shows the damage rate expressed in the unit of Q ·cm / (irradiation
particles/cm 2 ) as a function of the total energy transferred to all the prj mary knock e don atoms by an incident particle expressed in the unit of eV / cm 3 per incident irradiation particle. The ratio of the damage rate of CU3Au to that of copper for the irradiation at liquid heliunl temperature is about 8 independently of the total energy transferred. As it is considered that the resistivity change due to Frenkel defects is nearly
the same both in Cu Au and copper under the same irradiation conditions, the ratio of3
the number of pairs of wrongly sited Cu and Au atoms to the number of Frenkel pai rs
would be obtained to be 10. Here it is assumed that the resistivity is changed as 2.7
and 1.9 .o.·cm /%, due to 1 atomic % of Frenkel pairs and of wrongly sited atomic pairs,
respectively.
The results shown in Fig. 1 can be also used to estimate the size of stage I
annealing both in the alloy and copper. The fraction of stage I annealing is estimatedfrom the damage rates for irradiations at liquid helium and liquid nitrogen ten1pera tures as follows:f

L1 (J (He)-Ll (J(N)

L1 (J ( He)

It is 0.6------0.7 for Cu and 0.3 for Cu 3 Au. The stage I annealing of CU3Au contains
contributions both from defect annealing and order recovery. If the extent of defectannealings are assumed to be the same for both the alloy and copper, the fraction of
defect annealing in the alloy can be determined and the ratio of the number of wrong
pairs recovered in stage I to the number of defects (counted in the unit of Frenkel pair )annealed in stage I is obtained as follows:
nwrong pairIndefectThis sbows tha t during stage I annealing the stage I defects migrate to annihi late, during
which the ordering exchange replacement is brought forth, which makes three or four
wrong pairs disappear per one migrating defect.
The isochronal annealing curves of CU3Au and copper irradiated by alpha particles
at liquid nitrogen temperature are shown in Fig. 2 in the previous report,1) from which
the ratio of the number of wrong pairs recovered in stage II to the number of defects
annealed in stage II is obtained:IInwrong pair
n II

----3

defect

It is remarkable that the ratio of wrong pairs to defects in stage II is the sameas that in stage 1. This shows that the migrating defects are same in stages I and II atleast in their abilities to order wrongly sited atoms in alloy.
The results of stage III annealing shown in Figs . 1 and 2 in the previous report,
are most striking in this experimental study. The detailed numerical values of five setsof experiments were shown in Table 1. The ratio of wrong pairs to defects in stage III
is calculated from the results of each sets except the last in Table 1 as follows:

16.5

36.0

28.0

3.5

8.0

alpha

alpha

protonproton

1.20

3.0
0.09

0.37

0.58

0.84

2.4

0.83

1. 77

2.7

0.38

1. 93

2.2

2.5

4.0

(10- 8 D .cm)

(10- 6 D ·cm)

(10 16 / cm 2)

(MeV)

"\

CU

"

Cu 3 Au

(

Dose

\

Resistivity increase

293

283

276

275

278

(oK)

Cu 3 Au

(

275

266

260

260

259

(oK)

Cu

A

'\

1.06±O.02

1.06±0.01

1.06±O.01

1.06±0.01

1.07io.01

TIU(Cu)T III ( CU3Au)

Stage III temperature

Comparison of stage III temperature of CU3Au and eu.

EnergyalpharParticleA.

Irradiation

Table 1.

f-'

eN

o

104

n

n

III
wrong pairIII
def ect

This is an extraordinary value, which is about ten times larger than that for stage
II or 1. In the case of the last set in Table 1 the ratio is about 140. This means thatthe migration of stage III defects is ten times or more effective in ordering wrongly
sited atoms in the alloy than that of defects in stage I or II.

Reference
1)

H. Sakairi, E. Yagi, T. Karasawa, and R. R. Hasiguti: IPCR Cyclotron Progr.
Rep., -±, 140 (1970).

105

9-3.

Polarized Positron Annihilation

In

Ferromagnetic Nickel

N. Shiotani, T. Okada, H. Sekizawa,S. Ambe, T. Mizoguchi, and T. Karasawa(1)

Introduction

As a consequence of the non -conservation of parity in beta decay the positrons are
partially polarized along their direction of motion. When the positrons get into metals,
two -quantum annihilation can take place only from the singlet state of the positronelectron pair and two annihilation radiations are emitted in nearly opposite directions.
From the conservation of momentum the angular correlation of two annihilation radiations reflects the momentum distribution of annihilated positron -electron pairs. Since
in metals the positrons are thermalized before annihilation, the angular correlation
measurement can be used to distinguish the momentum distribution of majority spinelectrons from that of minori ty spin electrons in ferromagnetic metals. Such inves tigations have been reported 1),,-, 5) on single crystal Fe, polycrystals Fe and Ni, single
crystal Ni, ,and single crystal Gd.
We report here experiments on single crystal of ferromagnetic Ni oriented in the(110) plane with greater accuracy and better angular resolution than existing experiments cited above.
(2)

Experimental

The mechanical equipment and the 90Nb source preparation method were the sameas described earlier. 6),7)(i)
Specimen
Nickel of 99.999 %was melted and grown into a single crystal in a vacuum furnace
Movoble counter

Fixed counte r

Source

~W

VI
[=:J

~~ speci men

c=J
Nol(Tl )Mag netDetector(Nr)

Fig. l.

V3

CJ

c=J

No r (Tl )Det ect or(N)

Schematic diagram of the system.

106

with a built-in proper temperature gradient. The single crystal was oriented and cut
into a (110) plate. The surface was first chemically etched to remove distortion introduced during mechanical cutting, then finished by electropolishing. The Laue spots did
not reveal any distorti~on in our specimen.
(ii)
Slit system and specimen alignment
The three vertical slits, V l' V 2' and V 3' of 2.4 mm, 1.2 mm, and 2.4 mm widths
respectively, were used to collimate the annihilation r -rays as shown in Fig. 1. The
angular resolution defined by the sli t system was measured to be 0.66 Tnrad. The
specimen was placed exactly on the axis of the slit systenl. The (110) plane was pa ral lel to the axis. The source was set to face the specimen. Both the source and the specimen were in a magnetic field of 6 kOe which orients the electron spins in the specimen
either parallel or antiparallel to the direction of the posi tron beanl.
The direction of the annihilation r -rays from the specimen is parallel to (110) andthe component of the momentum exanlined is parallel to [1 ToJ. The direction of themagnetization of the specimen is either parallel or antiparallel to [lIoJ which is also
the direction of the positron beanl.
(iii)
Electronic circuits
The block diagram of the elec tronic circuits is shown in Fig. 1. The resolving
time was 500 nsec. During the measurements, the pulse height of the amplifiers was
examined every 6'"'-' 12 h and the levels of the single channel analyzers were adjusted sothat the coincidence was properly taken between two annihilation r -rays.
(iv)
Coincidence counting rate
The coincidence counting rate N (f), t) was measured at an angle 0 and the time twhich was defined to be the midpoint of the time interval of a counting. The rate N (f),t) includes the random coincidence rate N"( f), t), which is ei ther llleasurable by setting
the movable counter at a sufficiently large angle position or can be calculated from thefollowing relation:

where T is the resolving time, Nm (f), t) is the counting rate of the movable counter at
the angle f) and at the time t, and Nf (f) = 0, t) is the counting rate of the fixed counter at
the same time. Thus the time -independen t angular correlation NO (f}) is given by

where A =0.693 /T and T=14. 7 h for 90Nb . The final counting rate was obtained by summing up the counting rates of several runs wi th proper weights.
(3)

Results and discussion

Figure 2 shows the observed angular correlation curves taken under the following
conditions: The direction of the annihilation r -rays is parallel to [1 ToJ and the component of the momentum examined is parallel to [110J;
and(i)
The direction of magnetization of the specimen is parallel to the directionof polarization of the positron spins.

107

Direction of
external field

Di rection of
positron beamNi (1 10 )Top

Bottom- 20

Fig. 2.

-15

-10

-5

10

15

20

e In mrad

Angular correlation for a (110) crys tal of Ni. The shaded
curve in the figure shows the observed angular resolu tion
curve.

(ii)
The direction of magnetization of the specimen is antiparallel to the direction of polariza tion of the positron spins.
Since the volume in the momentUlll space filled with electrons is exactly the samefor both cas es, the curves are normalized to give an equal area.
Both curves show a hump around f} = 0 mrad., the shape of which depends on the
direction of magnetization of the specimen, and a sharp break near f} =3.2 Inrad. and aslight break near f} =7.3 nlrad.
The (110) -Brillouin zone boundaries occur at f} =7.31 nlrad. The above-mentioned
slight break near f} =7.3 mrad. is ascribed to the (110) -Brillouin zone boundaries.
According to the energy band calculations 8 ),9) the Fermi surface consists of four
sheets for the minority spin bands and one in the majority spin bands. The minority
spin sheets consis t of small hole surfaces at the [100J points in the 3rd and the 4th
bands, and a closed surface with protrusions along the [110J direc tions in the 5th band,
and a closed surface of nearly rectangular shape with protrusions along the [100J directions and [lllJ directions in the 6th band. The majority spin sheet is a multiplyconnected surface with necks at the [lllJ pojnts.
The nlinority spin surface in the 6th band cuts the [110J axes near f} =3.1 mrad.
and the majority spin surface in the 6th band cuts the same axes near f} =3.6 mrad. We
may thus expect that a break would occur between f} =3.1 mrad. and f}=3.6 mrad. on the
angular correlation curve.
The sharp break near f} =3.2 mrad. in the present data seems to correspond to theone mentioned above.
The hump around f} = 0 mrad. reflects the exis tence of the necks at the [lllJ
points in the majority spin surface and the protrusions along the [110J and the [100J
directions in the minority spin surfaces.

108'The authors are grateful to Dr. S. Okano and the men1bers of the Radiation Laboratory for valuable suggestion and kind pe rmission to use their electronic facilites.

References
1)
2)
3)
4)
5)
6)
7)
,8)
9)

S.S. Hanna and R.S. Preston: Phys. Rev., 109, 716 (1958).
P.E. Mijinarends and L. Hambro: Phys. Letters, 10, 272 (1964).
T.W. Mihalisin and R.D. Parks: Phys. Rev. Letters, lli 210 (1967).
T. W. Mihalis in and R. D. Parks: Solid S ta te Commun., 2, 33 (1969).
C. Hohenemser, J.M. Weingart, and S. Berko: Phys. Letters, 28A, 41 (1968).
M. Saito, T. Okada, N. Shiotani, H. Sekizawa, and T. Karasawa: IPCR Cyclotron
Progr. Rep., b 150 (1968).
N. Shiotani , S. Ambe, T. Okada, and T. Karasawa: ibid., 4, 146 (1970).
S. Wakoh and J. Yamashita: J. Phys. Soc. Japan, 1..2,; 1342 (1964).
J.W.D. Connolly: Phys. Rev., 159, 415 (1967).

109

10.

I PRODUCTION AND ITS APPLICATIONS

10-1.

Production of Radioisotope for Medical and Agricultural Use

M. Okano, T. Nozaki, T. Karasawa,
A. Shimamura, K. Yuita, and T. Ido

The production of radioisotope for medical and agricultural use has been con tinued. The separation of 54Mn formed simultaneously with 52Pe in the chromium tar ~et bombarded by 3He - or a -particles was studied, and the method of processing ofl lIn for diagnostic use was improved to be suitable for the routine supply. Efforts
have been made for the preparation of 18 p -labelled organic compounds. Also, 43K was
produced by the a -particle bombardment of streaming argon and was supplied to Kyushu
University.
54Mn was separated as follows. After the extraction of 52p e, gaseous HCl was
introduced into a solution of the bombarded chromium until its HCl concentration became about 11 N. The solution was then passed through a column of anion exchange
resin; 54Mn was adsorbed in it, but most part of the chromium and 58 V remained in
the effluent. The 54Mn was then eluted with water, and the eluate was brought to dryness. After addition of H2S04' HN0 3 and water to the residue, the 54Mn was distilled
in a stream of gaseous azeotropic HN0 3 - H2 0, the distillate being received by watercontaining a trace of H2 0 2 . Thus, 54Mn was separated free from carrier and salt in agood yield. The product was supplied to an agricultural laboratory.
Millicurie amounts of 18 p - labelled benzotrifluoride and choles tery 1 fluoride wereprepared. They were injected into animals, and their behavior was examined by ascintillation camera. The results, however, were not satisfactory, because most portion of the activity was trapped in the lungs. Efforts will be made to obtain the productsof higher specific activity. The preparation of some 18p -compounds less poisonous andless active physiologically is now being studied.

110

11. RADIATION MONITORING

11-1.

Routine Monitoring

K. Koda, 1. Sakamoto, and 1. Usuba

The results of measurements made during a period from April 1970 to March
1971 on the residual activities of the machine, the contamination on the floor of thecyclotron room and the personnel monitoring are described.
(1)

Residual activities of machine and floor contamination

The residual activities except for that of tritium (see below) seemed to havereached an equilibrium and gave a maximum dose -rate value of 10 4 mR/h at the septum
just after machine shutdown.
The surface contamination on the floor of the cyclotron room was kept to be about
5
10- tlCi/cm 2 similarly as in the preceding period.
(2)

Personnel monitoring

The accumulated dose of external exposure during the present period of all
cyclotron workers issued with the film badge are shown in Table 1. Both average andmaximum values of the annual exposure dose per person were a little less than those in
the preceding period.

Table 1.

Accumulated dose distribution of the cyclotron workers
from April 1970 to March 1971.

Dose (mrem)

10 ~ 100

101~300> 1 000
6

Operators
Nuclear physicists

6

6

4

Accelerator physicists

1

1

3

1

Physicists of other fields

44Radiochemis ts

2

1

2

2

Radia tion chemis ts

2

Biological chemists

2

Health physicists

2

Average annual dose per person: 299 mrem.
Maximum annual dose: 1090 mrem.

III

11-2.

Individual Monitoring for Internal Contamination with Tritium

K. Koda, 1. Sakamoto, and 1. Usuba

During the precedi ng period, two tes t runs of triton acceleration have been carriedout using 1 and 100 Ci of tritium gas, r espectively. The results of tritium monitoring inthese runs were reported previously. 1)
In the present period, the third run was done with 700 Ci of tritium gas from Dec.
21 to 26, 1970. As described by Kohno et al., 2) a tritium concentration of as much as
10- 3 ttCi/cc was found in the air inside the acceleration chamber and other parts of thecyclotron just after the exposure of the chamber to the atmosphere for overhaul. The
air contamination of such level was observed even 9 months after the triton accelerationin spite of routine use of the machine with inactive gases during that time, and this
implies slow releas e of tritium, probably in the form of tritiated water, from the innerwall of the machine which had been exposed to the tritium gas.
Tritium intakes occurred to several workers who were engaged especially in filament replacement during the triton acceleration or in overhaul after the machine shutdown. The amount of intake in these operations was assessed for each worker from thetritium concentration in urine using the equation as recommended by ICRP. 3) The data
are shown in Table 1.
The effec tive half -life of tritium in the human body es timated from the results ofday-by-day urine analyses was found to be about 9 days as shown in Fig. 1.

10 '

I

I

o

5

Dot e

1/ 10

Fig. 1.

10

I

15

I

1/20

20

25

I

1/30

I

I

30

35

I

I

40

45

2/10 (1 971 )E ffec tive half - li fe of tritium in the humanbody .

Healthphysicists

Nuclearphysicists

Operators

Accelerator
physici sts

{

l
{;

:

G

F

240

250

52

45

520

26

260

240

41

OverhaulMar. 1'"'-2

25

260

3230

430

560

OverhaulJan. 13~20 '71

1450

16f)0

350

D

r E

l20

lHO

C

B

A

De c. 2 1 ---- 26, ' 70

Tritium intake (uCi)

32

14

24

5

OverhaulMar. 11-----13

T ri ti um intake and total internal dose of c yc lotron workers.

Load ing and collectionof tritium gas, filament replacement, etc.

Table 1.

97

44

95

250

285

4

44

40

597

92

94

38

(mrem)

Total dose

N

f-'

113

References
1)
2)
3)

1. Kohno et al.: IPCR Cyclotron Progr. Rep., ~ 11 (1970).
1. Kohno et al.: This report, p. 16.
Report of Committee IV on Evaluation of Radiation Doses to Body Tissues fromInternal Contamination due to Occupational Exposure, ICRP Publication 10,
Pergamon Press, p. 29 (1968).

114

12.

L1ST OF PUBLICATIONS

1)

M. Aratani and N. Saito: "Charact e rization and Discussion of Charge
Spectrometer by Means of Ion Beam Experi111ent", Ra dioisotopes, l2., 22 (1970).

2)

M. Aratani and N. Saito: "Mass Spectroscopic Studi e s on the Me chanis111 of
Ionization of Atoms For111ed as a Result of Radioactiv e Decay Pro cess. I",
Mass Spectros. , ~, 906 (1970).

3)

S. Nagamiya, T. N0111Ura, and T. Yamazaki: "Stroboscopic Detenninationof the Magnetic M01TIent of the 8+ Isomeric Stat e of 208 po ", Nue!. Phys.,A159, 653 (1970).

4)

M. Aratani and N. Saito: "The Mass Spectrometry Using Ra dioisotop e s a san Ion Source", Mass Spectros. , ~, 195 (1971).

5)

H. Sekizawa, T. Okada, S. Okamoto, and F. Ambe: "Mossbauer Effect of
61 Ni in Spinel Type Magnetic Oxides", J. de phys. , g C 1 - 326 ( 1971).

6)

T. Nozaki, Y. Makide, Y. Yatsurugi, N. Akiyama, and Y. Endo: "A New RadioTracer Technique for the Evaporation Study of Light Elements from Molten
Silicon" , Int. J. AppI. Radiat. Isotopes, 22 , 607 (1971).

7)

S. Nagamiya, T. Katou , T. Nomura, and T. Yamazaki: "Magnetic Momentsof the 8+ Isomeric States of 90 Zr and 92 Mo ", J. Phys. Soc. Japan, 11.,319 (1971).

8)

T. Nomura, T. Yamazaki, S. Nagamiya, and T. Katou: "Magnetic Momentof the Lowest 6+ State in 42Ca and Effects of the Deformed States ", Phys.
Rev. Letters., 12., 523 (1971).

9)

S. Nagamiya and T. Yamazaki: "Evidence of Anomalous Orbital Magnetismof the Nucleon and the Mesonic Exchange Effect", Phys. Rev., C4, 1961 (1971).

10)

S. Nagamiya and T. Inamura: "Isomeric States in Neutron - Deficient PoIsotopes (A = 200 ~ 203) Studied by (HI, xn r) Reactions", Nucl. Phys., .:6)82, 84(1972).

11)

T. Inamura, A. Hashizume, T. Katou, and Y. Tendow: "Identification of Neutron
Deficient Isotopes 100Ag and 104 In ", J. Phys. Soc. Japan, 30, 884 (1971).

12)

I. Kohno, S. Nakajima, T. Tonuma, and M. Odera: "Elastic Scattering of Carbon
and Nitrogen Ions", J. Phys. Soc. Japan, lQ., 910 (1971).

13)

F. Suhadi, S. Kitayama, Y. Okazawa, and A. Matsuyama"Isolation of Radiosensitive Mutans of Micrococcus radiodurans", Agr. BioI. Chern., 35, 1645 (1971).

115

14)

T. Yamazaki and S. Nagamiya: "Unstable Nuclear Magnetic Probes(in Japanese)", Solid State Phys., ~ 323 (1971).

15)

T. Yamazaki:

16)

S. Yamaji: "The Manual of the Code for the form Factor Computation of the
Two-Nucleon Transfer Reaction", Sci. Papers LP.C.R.,~, Nos. 3 - 4, 79 (1971).

17)

F. Suhadi, S. Kitayama, Y. Okazawa, and A. Matsuyama: "Isolation and Some
Radiobiological Properties of Mutants of Micrococcus radiodurans Sensitive
to Ionizing Radiations", Radiat. Res., 49, No. 1(1972).

"Nuclear Magnetic Moment (in Japanese)", Buturi, 26, 637 (1971).

116

13.

L1ST OF PERSONNELIPCR Cyclotron Administration Committee=

HAMADA Tatsuji ~ 83 :i!
(Chairman)
KUMAGAI Hiroo ~~ 1=i Yr *IMAMURA Masashi ~:ttl§
KAMITSUBO Hiromichi J: H 7J;. :Ii
KARASA W A Takashi ~ ff('1t
MATSUDA Kazuhisa to 83 - !A.

MA TSUY AMA Aki ra to LlJ
NOZAKI Tadashi H ~IESAITO Nobufusa *]ff m- m
SAKAIRI Hideo ~ A !%. it
SEKIZAWA Hisashi ~ 1R

Jt;

fii]

Managers of Users GroupODERA Masatoshi

HAMADA Tatsuji
NOZAKI Tadashi/J" ~ IE 1~

IPCR Cyclotron Operating Personnel
Machine GroupHEMMI Masatake ~ Jt i& ~INOUE Toshihiko # J: fitJ. ~MIY AZ AW A Yoshitoshi 13 ff( 1t fIi'x

SHIMAMURA Akira ~:tt
TONUMA Tadao F 1?\ IE tit~

Operation
FUJ ITA Shin ]ff 83
jT
IK EGAMI Kumio ttl!. J: 11 = 95
KAG EY AMA Tadashi ~ LlJ
KOHARA Shigeo /J" J]{ £ *-IE

NAKAJIMA Hisao ~ ~ !oJ it
OG IWARA Kiyoshi ~ J]{
D1f
TERAJIMA Osamu~ ~;?gScientific and Engineering Personnel
Cyclotron Lab.
KUMAGAI Hiroo ~~ . '0- Yr x
CHIBA Yoshiaki T ~ fjf ~FUJISAWA Takashi ]ff If< ~ ~FUJITA Jiro ]ff 83~5
HEMMI Masatake ~ Jt i!jz ~HIRUT A Kotaro ~ 83 -.t:. ~5
INAMURA Takashi flli tr
INOU E Toshihiko # J: fitJ. ~KAMITSUBO Hiromichi J: H 7J;. :@KARASAWA Takashi ~ ZR.
'1t
KOHNO Isao fuJ HJ)J
MATSUDA Kazuhisa to 83 - !AMIY AZA W A Yoshitoshi '8 ~R. 1t fitJ.

=

*

*

MOTONAGA Shoshichi j[ 7k BB 1:;
NAGAMIY A Shoji 7]( 13 IE 15
NAKAJIMA Shunji ~ ~ 6l
NAKANISHI Noriyoshi ~ Tt§ m:: %OD ERA Masatoshi+ ~ IE 1~
SHIMAMURA Akira ~:tt~
TAKEDA Shigeru fr 83~
TONUMA Tadao F 1t5 IE tt
Y AMAJI Shuhei LlJ ~ 1~ f
YAMAZAKI Yoshishige LlJ ~ .& JJX
YOSHIDA Fusako a 83 m- -T
WADA Takeshi to EB
it

=

117

(Visitors)
FUJINO Takeo ~ H m: :;X.
(Inst. for Solid State Phys.)
FUJITA Junichi ~ EB M! (Tokyo Univ. of Educ.)
HANAZONO Sakae 1t ij]#:(lnst. for Solid State Phys.)
HARADA Kichinosuke jffi EB ELM(Japan Atom. Energy Res. Inst.)
KOIKE Masahiro + ttl!, IE 7i:.
(Inst. for Solid State Phys.)
NAKAI Koji ~ # f5
(Univ. of Tokyo)
NOMURA Toru H tt
1f
(Univ. of Tokyo)
YAMAZAKI Toshimitsu LlJ ~ ~ 7't(Univ. of Tokyo)=

Radiation Lab.
AWAY A Yo h ko ~ I¥ ~ -=r
HAMADA Tatsuji ~ EB :it
HASHIZUME Akira ~ m
KA TOU Takeo ;I]~ ~ m: :it

KONNO Satoshi 1ii !lff~
OKANO Masaharu Iti\J H Jt: If:]
TAKAHASHI Tan ~ ~1L
TENDOW Yoshihiko -ft.:@ 7.r ~=M

Nuclear Analytical Chemistry Lab.
AMBE Fumitoshi 1;; g~ )( ~AMBE Shizuko 1;;:g~ ~ -=r
ARA T ANI Michi m1:f ~ ~NOZAKI Tadashi
SAITO Nobufusa

H ~

IE

~ ~ -Fom(Visitors)
AKIYAMA Nobuyuki f'}( LIJ -Fo L(Komatsu Electronic Metals Co., Ltd.)YUITA Koichi ffin B3(Nat. Inst. of Agr. Scienses)
IDO Tatsuo }-t. pi :Ii tl(Nat. lnst. of Radiological Sci e nses)
YATSURUGI Yoshifumi J\ ~Ij IS')((Komatsu El ectronic Metals Co., Ltd.)'* -Radiobiology Lab.
MASUDA Fumihiro m EB )( t~
MATSUYAMA Akira 1i~ UJ~

IGARASHI Kazui 1i. T Ji\ - ~KIT AY AMA Shigeru it LIJ
Radiation Chemistry Lab.
IMAMURA Masashi

~ tt

s

MA TSUI Masaos

rt J.t IE :;X.

Metal Physics Lab.
HASIGUTI R. Ryukiti ~ 0
KOYAMA Akio + LlJ fIB ti
SAKAIRI Hideo J;& A. ~ it

~i

-2t

SHIOT ANI Nobuhiro
YAGI Eiichi /\(Visitors)
ISHINO Shiori .:tJ ff~(Univ. of Tokyo)
MISHIMA Yoshitsugu -=- ~ .&(Univ. of Tokyo)
SHIRAI SHI Haruki 8 1] *- fflt
(Nat. Res. Inst. for Metals)
T AN I Satoshi 1-t~(Univ. of Tokyo)**

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118

Magnetic Materials Lab.
OKADA Takuya [to] EB if! t!2
OKAMOTO Shoichi [to]:<$: ff -SEKIZAWA Hisashi

00 (R

fc)

Radiation Monitors
KOOA Kugao Ej3 EB ~ ~SAKAMOTO Ichiro W:<$: - f!5

USUBA Isao

fW ~

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IMAMURA Masashi ~ t1
NOZAKI Tadashi 1fl ~iE

00 ERA Masatoshi
SEKIZAWA Hisashi+ ~ iE1~

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119

AUTHOR INDEXf'}( LiJ -m ~AKIYAMA Nobuyuki* ~m)(~AMBE Fumitoshi

80

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KONNO Satoshi

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KOYAMA Akio

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KUMAGAI Hiroo

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A*-=!ZQ f!583

KUSUNO Sadao

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FUJITA J iro

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NAKANISHI Noriyoshi

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KARASAWA Takashi

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NOZAKI Tadashi

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KATOU Takeoti M

OD'ERA Masatoshi

KODA Kugao

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fiiIlfOKANO Masaharu

KOIKE Masahiro:rj]

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