the Institute of Physical and Chemical Research
Wako-shi, Saitama Pref., JAPANIPCR cyclotron
Progress Report 1972

Vol. 6

Edited by Administration Committee of the IPCR Cyclotron,peR

Cyclotron Progress ReportVol. 6The Institute of Physical and Chemical Research"'RIKAGAKU KENK YUSHO" Wako-shi, Saitama, 351 JAPAN

December, 1972

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.

CONTENTS
Page
1.

INTRODUCTION

2.

MACHINE OPERATION

3.

MACHINE DEVELOPMENT AND ACCELERATOR PHYSICS...................................................................

2

3 -1.

A New Irradiation System.... ..... .... ....... ..... ....... ...... ........ .... ....

5

3 -2.

Improvement of the Central Region Geometry and theExtraction Efficiency of Beam .................................................

7

Polarized Ion Source
On the Construction of a Strong Field Ionizer
and Meas urement of Its Ionization Efficiency

12

3-4.

A Proposal of New Heavy Ion Accelerator System

15

3 -5.

The Variable Frequency Linac Project
Construction of a Model Cavity .........................................

16

The Variable Frequency Linac Project
Quadrupole Magnetic Field Gradient Necessary
for Focusing Very Heavy Ions ....... ........ ............ .... ............

18

3 -7.

A Study of Heavy Ion Source for a New Accelerator

20

3 -8.

A Quadrupole Magnet of Compact Size

3 -3.

3 -6.

4.

1

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

21

NUCLEAR PHYSICS
Scattering and Reactions
4 -1.

A Study of Transfer Reactions Induced by 90 MeV
14N on 52Cr ....................................................................... .

23

Selective Excitation of One Proton Configuration for
53Mn in 52Cr(14N, 13C)53Mn and 52Cr(12C, I1B)53Mn

27

Gamma Transition from the First 3 - Levels in'9 4,96,98,10·0 Mo .................. .................. ........ ............ ............

30

4-4.

Inelastic Scattering of Deutrons by Even Mo Isotopes

33

4 -5.

Unbound Isobaric Analog States Induced by
50,52,54Cr(h,d) 51,53,55Mn Reactions .................................... ..

35

The DWBA and Coupled Channel Analyses of
Inelastic Scattering of 3He from 12C ................................. .

37

4-2.

4 -3.

4 -6.

5.

4 -70

20Ne(d, 6Li) 16 0 Reaction 000000 ............................ 0...................

43

4 -8.

Inelastic Scattering for the Giant Resonance States

45

4 -9.

Effect of Exchange Currents on Orbital g-Factors

47

4 -10.

Total Energy Surface for 236 U in the Two-Center Model......... ...

49

4 -11.

On the Mechanism of (3 He , t) Reaction

53

4 -12.

Coupling between Valence Nucleon and Clusterized Core

The Gamma-Decay of 146,150,152S m following the(a ,2n) Reaction .................................................................. .

66

5 -2.

Decay of 87Z r and 85Z r (II) .................................................. .

70

5 -3.

Magnetic Moments of High -Spin Isomeric States
in Po Isotopes .................................................................... .

73

A Method of Meas uring Alpha -Decays in the
Nanosecond Range .............................................................. .

76

Alpha - and Gamma -Spectroscopy of N=128 Isotones
216Ra, 217Ac, and 218Th ..................................................... .

80

g -Factor Meas urement of the 8+ Sta te in 86S r
Produced in Kr Gas ............................................................. .

84

5 -4.

5 -5.

5 -6.

NUCLEAR INSTRUMENTATION
6 -1.

6 -2.

6 -3.

6 -4.

7.

58

NUC LEAR PHYSICS
Nuclear Spectroscopy
5 -1.

6.

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

A Dual Ge(Li) Gamma -Ray Spectrometer for
Nuclear Study .............................. .................... .. ................ .

87

Particle Identification Study for Z = 3 to Z = 7 Particles
Using a Power-Law Type Particle Identifier .............................

89

On a Model of Wire Spark Chamber with Ferrite Memory
Cores for Broad Range Magnetic Spectrometer .........................

92

Meas urements of Ion Optical Properties of A Particle
Analyzer by Particle Beams ...................................................

96

RADIOCHEMISTRY
7 -1.

The Behavior of Trace Amounts of 18F Atoms Trapped on
Metal Surfaces ...................................................................

99

7 -2.

7 -3.

7 -4.

8.

8 -2.

8 -3.

10.

A Radiochemical Study of Oxidation States of 119Sb after the
EC Decay of 119 m Te in Te02 and H6Te06 '.......... .... .................

104

Radiochemical Studies on Carbon, Nitrogen, and Oxygenin Semiconductor Silicon ......................................................

106

Radiolys is of Binary Mixtures of Tetrahydrofuran
and Benzene in High LET Region ......................................... ...

108

LET Dependence of Spatial Distribution of Free Radicals
in Irradiated Crystalline Eicosane ..........................................

110

LET Effects on Bacterial Cells

114

SOLID STATE PHYSICS
9 -1.

Positron Annihilation in Ferromagnetic Nickel

119

9 -2.

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

122

9 -3.

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

125

RADIOISOTOPE PRODUCTION AND ITS APPLICATIONS
10-1.

11.

102

RADIATION CHEMISTRY AND RADIATION BIOLOGY
8 -1.

9.

A Mossbauer Spectroscopic Study of Chemical States of 119S n
after the EC Decay of 119Sb in Sb203 and Te02 ........................

Prod uction of Radioisotopes for Medical Use

127

RADIATION MONITORING
11-1.

Routine Monitoring

130

12.

LIS T OF PUBLICATIONS .................... ..... .. ..... . .... ...... .. .. .......... .... ...

132

13.

LIS T OF PERSONNE L

134

14.

LIST OF OUTSIDE USERS AND THEIR THEMES137

AUTHOR INDEX

141........ ........ ................ ........ .... .. ...... ............ ...

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

1

1. INTRODUCTION

In these seven years since the first beam of the cyclotron was obtained, a great
number of investigations have been done in various fields of research. The accumu1ation of these works as well as the worldwide studies revealed that heavier particles as
projectiles would become a new powerful probe to search for the regions unexplored yet.
To meet the requirements of workers who want to have this new probe, a preliminary
study of a new machine for heavy-ion acceleration was made two years ago as describedin the 1970 report. Sine then, design stu dies of ion sou rces and acceleration systems
have been started and a concrete project is being drawn up. It is hoped the project will
be supported and realized in the near future.
Improvements in various features of the machine are made incessantly. Amongthem, it should be pOinted out that the polarized ion source has been constructed and its
testing is now under way.
Most of the works carried out in this year are continuation from the previous year.
Besides, some theoretical studies on nuclear physics are included in this report.
The Cyclotron Board has been organized in this year and the former Administration
Committee was replaced by the Users' Committee. The Board is expected to facilitate
the management of the research programs and the development of the new accelerator
project in connection with the situation outside as well as inside of the Institute.

Yukio Miyazaki, Chairman
The Cyclotron Board

2

2. MACHINE OPERATION

Machine Group

During the period from Oct. 1971 to Oct. 1972 the cyclotron was operated on the
24 h a day basis as in previous years. "On beam" time had totaled 5300 h. Table 1
shows a brief statistics of the period. One-third of the beam time was used forresearches using heavy ions. Table 2 shows the scheduled machine time allotment.
More than 95 %of the schedule was fulfilled. Table 2 contains also such times as forperiodical machine inspection and repair, ion source exchange etc. when the cyclotron
stops its work.
After 5 -year continuous operation for about 30000 h, some parts of the cyclotron
had to be replaced or repaired. One hundred cooling water relays were replaced in thesummer overhauling period by new type ones, which had passed one -year life tests. In
the same period, nearly 200 rubber hoses which had been used to supply cooling water tothe dee system at 1 kV DC potential were replaced by Nylon tubings. After the overhaul
a drastic decrease of leakage current was observed. Less electro-deposition trouble inthe cooling circuits is expected. The target holder for production of radioisotopes in
the accelerating chamber was replaced by a newly designed one. A new dee voltage
pick -up electrode was installed at the side of the east dee at the beginning of 1972 andhad been used in parallel with the old ones. Ventilation around the ion source control
panel was improved to prevent any accident by misoperation of the gas vessels. Beampipes to each experimental area were provided with new vacuum systems.

Table 1.

Machine operation time by indication of
w orki ng time meter.

Date

Oscillator on

Ion so ur ce on

Oct. 1971

22118.0 (h)24204.8 (h)Oct. 1972

27411.0 (h)29880.0 (h)365 days5293.0 (h)5675.2 (h)Percent of 365 days

60.5 %

66.1 %

Schedule for this period:
Machine time214 (days)

Overhaul and installation work

40 (days)

Periodical inspection and repair

28 (days)

Vacation, holiday, and Sunday

83 (days)3

Table 2.

Scheduled machine time and subject of
research in this period VII.

Subject

Hours

Percent

Hea vy ion reaction

720

Direct reaction

1056

Nucl. Phys.

In -beam spectroscopy

1200

58.2 %

Radio -isotope production for nuclear spectros copy

331

Nuclear chemistry and radio -isotope production

286

Radiation chemistry and radiation biology

341

Solid state physics

365

M6ssbauer source

72

Track detector

11

Nuclide identification study

67

Particle analyser calibration

168

Cyclotron condi tioni ng

12

Fields otherthan Nucl. Phys.

20.1 %

Accelerator
Phys. and
MaintenanceAlignment of beam handling system

50

Machine inspection and repair

672

Exchange of heavy ion and ordinary ion sources

56

Reserved for machine time adjustment

48

Use by other organizations

228

4.0 %

5683

100.0 %

17.7 %

4

As a consequence, vacuum pressure at each channel has been improved by an order ofmagnitude. The diffused image of beam has disappeared, which was thought to occur inmost cases from charge changing process by the residual gas molecules when heavy
ions were transported to the end of a long beam pipe. The interlock system for vacuum
condi tion described in the last year's report was installed. It is found useful tomaintain a high performance of the vacuum system.
All the planning and design of these modifications have been made by the machinegroup and operation personnels. Detailed design and manufacturing have been done by
the machine shop of this . institute. Installation and adjustment ha ve been carried out
again by the machine and operation groups.

5

3. MACHINE DEVELOPMENT AND ACCELERATOR PHYSICS

3-1.

A

New Irradiation System

A. Shimamura and T. Inoue

The new irradiation system described in this report has been installed for radioisotope production in the cyclotron chamber and can be used easily by general users
without any special trai ning. Target bases are made of copper or aluminum plates of
60 x 80 x 10 mm. These plates can be replaced easily when they are contaminated withradioactive isotopes. The improved point is that the back sides of target bases are
directly cooled, making efficient cooling possible. When the targets are in the cyclotron
chamber, vacuum sealing of the plates is made by O-rings against water pressure.
After the irradiation the remaining cooling water is driven out by air blowing and then
the target is taken off. All thes e operations can be made remotely.

Fig. 1. Flow diagram of sequential operation of the installation.

6

There are two beam probes provided with slits before and behind the target. The
purpose of these beam probes is to let cyclotron beam fall properly on the target. The
angle of incidence of the beam on the surface of the target can be varied within ± 30 0 .
Ex tra rotation of 270 0 is pos sible if the irradiation of the othe r s ide of the target isdesired. The angle is shown on the central control panel by a position indicator. Eachof the target and the beam probes are connected to a current integrator and two current
meters in the central controlling sets.
The installation is operated step by step in a sequential manner. It has
indispensable interlocking· at each step and switching onto the next step is possible only
when certain conditions of the intermediate section are satisfied. The order ofoperation is indicated in Fig. 1.
The controlling sets of this installation are located in the cyclotron vault and in
the central control desk. One can operate them at both sites without switchi ng the local
and remote indicators. We have made the dimensions much smaller than the old one 1 )in order to make the space around the cyclotron larger for the convenience of exchangeof ion source.

Reference
1)

A. Hashizume-and A. Shimamura: IPCR Cyclotron Progr. Rep., l, 73 (1967).

7

3-2.

Improvement of the Central Region Geometry
andthe Extraction Effic iency of Beam

Y. Miyazawa, K. Ogiwara, S. Fujita, M. Hemmi, K. Ikegami,
T. Inoue, T. Kageyama, S. Kohara, H. Nakajima,
A. Shimamura, O. Terajima, and T. Tonuma
The initial orbits in a cyclotron are crucial in determining the properties of thebeam at the final orbit. Also, good positioning of the deflector channel as well as agood quality of beam at the maximum radius is necessary to obtain a good extraction
efficiency.
To make its concept precise, we define the extraction efficiency as the ratio of theextracted beam current, measured at the downstream of the deflector channel, to theinternal beam current measured at 66 em radius for light ions. For hea vy ions, theinternal beam current is measured at 70 em radius rather than at 66 em because theinternal beam current decreases with the radius by the charge exchange loss during theacceleration.

[
3

Cross-section (A-A/)

Fig. 1. Schematic drawing of the central
geometry in the cyclotron. For
the acceleration of heavy ionsthe screen is not provided.

8

840

/./

830

,J:'

820

/'

810

~

~'

800

'"c:
790

o
E

780

"7f!
!J;l

'"

;;~/

~ 770

~v

-0

o

E

~'

Beam orbit

'"

/

760

~'

a.

'"

(f)

750

4
- ---

#',
' Septum before correction-~ Septum ofter correct ion! - 10o

10Entrance of septum

20

30

Angle

40

50

60

'deg.1

Fig. 2. Correction of the septum at the entrance part.

\Sept. 1971

.~

10

.~

c4+ 75MeV P=4.3X 10- 6 (Tor.)
4He+-t 2\ MeV

43c'"t: 5
~

u

E
0

'"

CD

o

30

40

50

70

60
Radius

80

90

(em)

Fig. 3. Beam attenuation curve before corrections.

9Jon. 197250--.-.-.-.,

TL = 38%

\

~ 30

\

\

\

OJ

20

u

\

E

....

_-_.,.\~co 10

Rad iu s

\

I

70

50

80

90

(em)

Fig. 4. Beam attenuation curve after corrections of
the central region and deflector channel.

70
-

<l

60

Oct. 1972
\

.\.

c

Q)

L
L
OJ

u

1J.=~=67%hs,.-.-.-._._.-.-_.-...

..3- 50.....,

17 MeV

\

40
30

~ 20

co

10
0

!

30

40

50

60

Rod ius

70

'-.

.5 30

3H~+

".-./.~.--.-.-.

-.

40MeV

.,

\ ._-_._._._.\

Q)

L

~

20

\

10

o

~I--~!~~!--~I~~!--~I--_\90
30
40
50
60
70
80
Radius

(em)

4

<l

Sep. 1972

\

3

3-

80 MeV

"'-..

+'

C
<l>
L
L
OJ

1J. = 64%......... -.-.-.- .........

c

r:n

90

Oct. 1972
\

~

80

(em)

40
<l

\.._._.\
1_\

2

'-'

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

11= Iso = 61 %170

p= 6.6 X 10- 6 (Tor. ).....~ ............

E~.......

' -...

co\1.._-_._--

o

30

40

50
Radius

60

80

90

(em)

Fig. 5. Beam attenuation curves with the axial slit after correctionsof the central region and deflector channel.

10Since Feb. 1972, the central region geometry was changed as shown in Fig. 1, sothat the first orbit is shielded effectively from the rf-field. The height of east wings is
25 mm. The screen which is made of molybdenum plate (2mm thick, 70 mm wide, and
50 mm high) is screwed on the supporting tube of the light-ion source. The axial slit
indicated in Fig. 1 was not provided at that time. For the acceleration of heavy ions,
we did not use a screen at the central region.
Besides, the exit part of the deflector was modified to have a larger radius ofcurvature to fi t the orbit. The correction of the septum at the entrance part was done
over the-angle from -150 to 0 0 as shown in Fig. 2. By this improvement, the electric
discharge at the channel exit was decreased and we could get a larger effective electricfield for the beam in the deflector channel.
Figure 3 shows a typical beam attenuation curve before the corrections were done
early in this year. In this case, the extraction efficiency was from 20 to 30 %for lightions and only 10 % for heavy ions.
Figure 4 shows a beam attenuation curve after the corrections of the central
region and the deflector channel were applied. The extraction efficiency was improved
to be about 40 % for light ions and about 20 %for heavy ions on the routine operationbasis until the following modification was made.
To eliminate the axially spreading beam, the axial defining slit made of graphite
was provided since Sept. 1972 in the west wings as shown in Fig. 1. It clips the heightof beam at- the first and second turn within 15 mm.
The beam attenuation curves with the axial slit are shown in Fig. 5. With thesemodifications the extraction efficiency has risen to about 47 % for light ions and about
35 % for heavy ions. These values are attainable without any special procedure in
operation. With careful tunings, a maximum extraction efficiency of 67 % has beenrecorded for light ions and 60 % for heavy ions. The transparency of the deflector
channel, which is the ratio of beam leaving the deflector to beam reaching the deflector,
is about 70 %.
( B -B')( A-A' )fDeflector

Water
A

Copperplate

Graphite
plate

I

Tungsten plat e( 160 LXI48HX O.5tI

Fig. 6. Deflector cross section and septum shape of thecyclotron.

11

Figure 6 is the deflector cross section and the septum shape. For the long time
continued operation, 1.5 kW can be dissipated in the simple slotted tungsten septum of
0.5 mm thickness.
By the enhancement of the extraction efficiency, the life time of the septum
entrance has increased from 600 to 2000 h. Figure 7 shows an actual performan~erecord obtained from the operation diary over the last one year. In this plot, the bad
extraction efficiency can be interpreted to be due to misadjustment of the deflector
channel and the deflector voltage.

10000<'Xlllx 3HeH

(0 )

o 4
I:D

12!3

:-

He

00

o 0

0

~Fr

a..

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b.

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<{

.:=-

3-

+

+

:z

... '"u '-Vacation Overhaul

0

x

.

30

X

10

0

c

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~ ~~

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11

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0

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~ 0

Ix 0

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6

12
1972

"

~ b.

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o •

It>

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0

"l21

I.
I
I
Vacat ion Overhaul

b.
0

0

oX

x

It>

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)(

~ 20 X 00
cPo
a.

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x
(

... ~ 10 ...x.

0.5

)(

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(c)

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.

b.

x

..

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b.

b.
0
0

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1Zl~

f1

~

0
0b.
0

0

10

I Mont h)(a) Particle energies used for experiments.
(b) Beam extraction efficiency.
(c) Extracted beam currents which were actually employed in experiments.
Fig. 7. Plot obtained from the operation diary.
septum entrance.

Arrows represent the repair of

12

3-3.

Polarized Ion Source

On the Construction of a Strong Field Ionizer and Measurementof Its Ionization Efficiency

S. Motonaga, T. Fujisawa, K. Ikegami,
H. Takebe, and M. Hemmi
Measurement of an ionized beam has been made to investigate the properties of astrong field ionizer for an atomic beam type polarized ion source and improvement inorder to obtain the higher ionization efficiency is now being attempted.
In a previous measurement of atomic beam, the intensity of 1.5 x 1015jcm 2 .sec
was obtained. However, in order to get ion beam intensity of the order of /1a for thesource output further improvements were necessary in each part of the polarized ion
source system.
(1) Construction of strong field ionizer
Basic design of the strong field ionizer is similar to that described by Glavish.1)
Mechanical details of the strong field ionizer is shown in Fig. 1. The atomic beam isionized by electron collision in a cylindrical region 1 cm in diameter and 14.5 cm long,where a magnetic field of about 1500 gauss is applied parallel to the axis. The solenoid
and various electrodes of the ionizer have a common axis.
IONIZERI

I

Ion pump( 500 lis for air)I

I~----';;;;"'Salenaid

Dwinding

I

I
I

Atomic beamc:=>

W---~~~Itr---:IT1lmmn1lTlT1 -1l1lT-1l11IIIl111nnnr

I on beam

I

E~Cu)

E (Cu.

&:
5~_~_ _~St ainless)
Extra ctors

Extractor s

( CuI

o
Ion pump( 1251/s tor air )Fig. 1. Strong field ionizer.

50 mm...J..
' ..J., .L' ,-,--,--,' i-J"

L...\'

13

The ionizing region is evacuated by two ion pumps to a pressure of the order of
10- 6 to 10- 7 Torr, to avoid as far as pos sible the presence of unpolarized hydrogenfrom the residual gas in the ionizing region.
The hollow electron beam is produced by a circular filament and accelerated toabout 600 V relative to the filament. A negative voltage at E3 (about 4 kV) repels theelectrons backward, so that the electrons can oscillate back and forth throughout the"ionization column", being confined in a cylindrical sheet by the action of magnetic
field. Wi th multiple reflection the filament emission of 20 to 50 mA gives rise to a
space current up to 100 mA. A photograph of the hollow electron beam is shown in Fig.
2.

1111'lllijllllljlllmllij

10L

11
I

Fig. 2. Photograph of a typical hollow
electron beam.

40

- 30

«
.3

= .1#/Hzl = 4.8 X 10-

10

3

O~~--~1.0~~--~2~.O~~--~3.=O--~~4~. O~~--75.~OHz

pre ssure( X10- 6 torr)

Fig. 3. H2 + ion current as a function of H2
press ure.

14

The positive ions are extracted by the negative electrode, and a positive ion beam
is formed and properly accelerated by means of a system of electrostatic lenses E5'
E6 ,and E7·(2) Ionization efficiency
When hydrogen gas is admitted to the ionizer vacuum chamber and an increment inpressure of AP(H 2 } produces an increment in H2 + ion current of Ji (H2~' the ionization
efficiency is given by L1i(H2+)/ L1P(H2}' Typical results are shown in Fig. 3. A
measured value of efficiency is obtained at 4 x 10- 3 . It is noted, however, that asindicated in the figure, the background by residual gas is very large. The presence ofhydrogen molecules in the ionization vacuum chamber can be a source of unwanted
background.
In order to reduce the remanent current, development of an ionization column andvacuum devices are now in progress.

ReferenceI}

H.F. Glavish: Nucl. Instr. Methods, 65, 1 (1968).

15

3-4.

A Proposal of New Heavy Ion Accelerator System

M. Odera and H. Kamitsubo

The Cyclotron is now operating on the 24 h a day system over 5000 h per
annum. As an only facility in Japan that accelerates heavy ions up to 100 MeV, about
30 % of the machine time are used in the researches by heavy ions. Not only nuclear
physicists but also people of radiation chemistry, biology, and solid state phYSics areusing the beam on the regular basis.
As the structure of the heavy ion source is more complex than the ion source forlighter projectiles and wear and tear are heavy owing to the large power dissipated init, the maintenance work of technical persons has already become to a limit. Yet, there
are desires for more heavy ion machine time, more ion species, more energy range,and so on.
In view of the above -mentioned situation a proposal to construct a new heavy ion
accelerator was made)It will enable to accelerate ions in a wide range , or preferably
all the elements at least to 7.5 MeV per nucleon. The energy can be varied, if notcontinuously, and the intensity of the beam will be moderate. According to the plan,
the system consists of a variable frequency linac 2 ) as a prestripper accelerator andanother accelerator as a post -s tripper one. The latter will probably be a separate
sector type isochronous cyclotron. 3 )Table 1 shows maximum energies of various ions at the exit of the linac. Theenergy is amplified at a constant factor, say ten, if a separate sector type was chosen as
a post-stripper machine.
Table 1.

Energies of ions to be accelerated in thevariable frequency linac.

Ion

6 Li 2+C4 +Ar 6 +

Kr 8+

Xe 9 +

Energy
(MeV)

40

80

120

160

180

References
1)
2)
3)

Proc. VIth Intern. Cyclotron Conf., Vancouver, B. C. Canada (1972).
M.Odera: IPCR Cyclotron Progr. Rep.,~, 16(1972); M. Odera and T. Tonuma:
ibid., p. 18 ; M. Odera and M. Hemmi: ibid., p. 21 .
K. Matsuda: Sci. Papers I.P.C .R., 66, 33 (1972).

16

3-5.

The Variable Frequency Linac Project

Construction of a Model Cavity

M.OderaTo extend the present heavy ion acceleration capabili ty of the Cyclotron facility,
we have proposed a new type accelerator complex .1), 2) It consists of a variablefrequency li nac as a pre -s tripper accele rator and another accelera tor, probably a
separated sector cyclotron, as a post-stripper one. 2 ),3)
Unlike conventional fixed frequency linacs which accelerate different kinds of ionsto the same velocity irrespecti ve of the charge states of particles, this type gives higher
velocity to ions of larger charge to mass ratio than to those of smaller ratio. For
instance, while Xe 9+ ion attains 1.4 MeV per nucleon, C 4 + can reach 6.6 MeV/nucleon
or 80 MeV total in the present design. These relatively high energies for lighter
prOjectiles together with wide range of mass available will make the linac usefulaccelerator by itself alone for research and application.
Figure 1 shows the linac schematically. By changing the volume of the cavity at
the voltage and current loop, the frequency can be changed in a wide range. The
technique is quite similar to that being used in the present Cyclotron. Of course, there
are some problems peculiar to the linac as high frequency and high power technique.
Figure 2 is a real scale model cavity constructed to study these pOints. Test will startfrom the fall of 1972.

Fig. 1. Variable frequency linac cavity.

17(a) The cavity with a side panel removed.

(b) The drift tubes.
Fig. 2. Photograph of the real scale model cavity.

References
1)
2)
3)

M.Odera: IPCR Cyclotron Progr. Rep., 1, 24 (1970).
M. Odera and T. Tonuma: Proc. mth Intern. Cyclotron ConL, Vancouver, B.C.
Canada (1972).
K. Matsuda: Sci. Papers I.P.C.R., 66, 33 (1972).

18

3-6.

The Variable Frequency Linac Project

Quadrupole Magnetic Field Gradient Necessary for
Focusing Very Heavy Ions
T. Tonuma, F. Yoshida, and M. Odera

Combination of alternately convergent and divergent magnetic lenses overcomesthe radial defocus ing force given to an ion beam by the accelerating rf -fie ld at the dri ft
tube gaps in a linear accelerator)
The magnetic field gradient of a quadrupole
magnet in a drift tube necessary for focusing depends on the voltage of an injector in
addition to the ratio of charge to mass of an ion and the rf electric field. Figure 1
shows field gradients required for quadrupole magnets when the voltage of the injector
40~D ~ D ~ D _i
Fo D1 Fl D2 F2 0 3 F3~~----------------~

E

u

30

........
19~

300kV 500kV 750kV

~ ~

t!)

+-'
c

~ ~

Q)

~ ~

"0
0
L
0'1

D

- - -- IT

r-l ---- 3n:
L_ J

20

"0
Q)

'+-

Upper limit

mle=22, t= 18.4MHz

Lower limit

m/e=3 ,f=50MHz

U

+-'
Q)

c
0>
0

~

10

0~~=Fo~~-=Fl~~~F~2~~~3~~-F-4~~-F5~

Drift

tube

numberFig. 1. Magnetic field gradients necessary forfocusing. The calculation was carried out
by using the following values of parameters:
EV = 1.5 x 104 kV2/ cm , minimum gap 3 em,transit time factor 0.85, and CPo = 65 0 for
synchronous particles. Here E and V are
the electric field and potential difference
between drift tubes, res pecti vely .

19

is 300, 500, and 750 kV, other parameters being kept constant. The field gradientswere estimated for quadrupole magnets provided in the flirst several drift tubes at earth
potential. Because the necessary field gradients decrease with increase of ion
velocities, the largest value is required for the magnet at the entrance of the linac.
Solid lines give the field gradients for which the phase of the rf-field changes by 7r
radian during the passage of the particle through a drift tube. In this case, however, afield gradient of above 10 kG/ cm for the first few sections is required for focusing,which is difficult to realize technically. This difficulty is avoided by use of a longer
drift tube having a quadrupole magnet in which the phase of rf-field changes by 3 7r , andthe focusing requirement is satisfied with a smaller gradient as shown by dotted lines.
In the figure the upper limit and the lower limit of the field gradient correspond to mle =22, f = 18.4 MHz and mle = 3, f = 50 MHz respectively and this region contains the field
gradient necessary for acceleration of particles expected to be accelerated in the linac.
The result of this calculation may be useful to discuss what voltage should beselected for an injector.

Reference
1)

T. Tonuma, F. Yoshida, T. Wada, and M. Odera: IPCR Cyclotron Tech. Rep.,
No . 5 (1972).

•

20

3-7.

A Study of Heavy Ion Source for a New Accelerator

1. Kohno

Since the construction of a new heavy ion accelerator was planned in thislaboratory, an ion source for the new machine has been studied. Previously a multiplycharged heavy ion source of the radial extraction PIG type has been successfully used toaccelerate several kinds of ions such as C 4 +, N4 +, N5+, 0 5 +, Ne, Ar, Kr, and Xe,l) in
the cyclotron, therefore the experiences obtained could provide a starting basis for the
study of new source. The following improvements should be made to satisfy therequirements of the new machine.
(1) The number of elements to be used for producing multiply-charged ions,must be increased greatly, because the new machine intends to accelerate many kindsof projectiles. For this purpose, the ion sources for solid state samples are being
developed. They have a furnace or a sputtering electrode.
(2) The ion beams extracted from the source must have an emittance as small as
possible in order to be accepted and accelerated efficiently by the new machine whi.chwill be a li nac .
As is well known, the linac type accelerator has a relatively small radial phase
acceptance. The value of the permissible phase space depends on the voltage ofpreacceleration before injection into the linac as well as on the source emittance.
Tentatively, 100 mm mrad. were chosen as a design goal for a beam extracted by 20 kV.
To this end, preparation is now made for the sources of duoplasmatron type and PIG
type with axial extraction. The test bench apparatus used for the development of theion source of the cyclotron 2 ) is being modified in these studies. Ion source for solidstate material will be investigated by the test bench in the next year.

References
1)2)

1. Kohno, Y. Miyazawa, T. Tonuma, S. Nakajima, T. Inoue, A. Shimamura, K.
Yoshida, and T. Karasawa: lPeR Cyclotron Progr. Rep., ~, 6 (1969); 1. Kohno,
Y. Miyazawa, T. Tonuma, T. Inoue, A. Shimamura, and S. Nakajima: IPCR
Cyclotron Progr. Rep., ~ 5 (1971).
1. Kohno, T. Tonuma, and S. Nakajima: J. Vacuum Soc. Japan, 10,27 (1967).

21

3-8.

A

Quadrupole Magnet of Compact Size

M. Odera and M. Hemmi

A small quadrupole magnet was manufactured and tested. It was aimed toascertain the possibility of obtaining a high gradient quadrupole field necessary forfocusing the heaviest element to be accelerated in the linac under contemplation)
Figure 1 is a photograph of the magnet, of which the outer diameter is 12 cm andthe aperture for beam is 16 mm. The coil is wound with a copper pipe of 6 mm 0.0.
and 4 mm 1.0. insulated with glass fiber tubings. It is cooled by water flowing inside.

Fig. 1. Photograph of the tes t quadrupole magnet.
10

E

u

.......

8

<.!)

-0
Q)

6

'+--I-'
Q)

c

cr>
0

4

~

2

Excitation current(A)

Fig. 2. Excitation curve of the magnetic field gradient.

22(kG/em)
10

SOOA

200 A

100A

o
-x

Fig. 3. The extent of constancy of gradient.
Figure 2 shows an excitation curve and Fig. 3 shows the region of cons tancy of the field
gradient along the axis. The radius of curvature of pole tips is 1.125 times the radiusof the aperture. The value of gradient is sufficient to focus the heavies t ions to beaccelerated in the linac by use of a 3 7r mode acceleration for the first few sections ofdrift tubes .2)

References
1)
2)

M. Odera and T. Tonuma: Proc. VIth Intern. Cyclotron Coni., Vancouver,
B. C. Canada (1972).
T. Tonuma, M. Odera, and F. Yoshida: IPCR Cyclotron Progr. Rep., ~,18(1972).

23

4. NUCLEAR PHYSICS
Scattering and Reactions

4-1.

A

Study of Transfer React ions Induced by

90 MeV 14 N

on 52 Cr

1. Kohno, S. Nakajima, 1. Yamane, M. Yoshie,
M. Odera, and H. Kamitsubo
It was reported recently that transfer reactions induced by heavy ions show two
types of reaction mechanism. In one case the cross sections for di rect reactions
giving discrete energy spectra are strongly enhanced, and in the other case energy
spectra have not a selectively enhanced peak, but a broader distribution. In order tostudy the mechanism of reactions to transfer one, two, three or four nucleons in moredetail, we measured transfer reactions induced by 90 MeV 14N on 52Cr using thecyclotron.
The method of measurement was described in another paper of this progress
report)In Fig. 1 the P.1.0. (Particle Identifier Output) spectrum for 52Cr + 14N is shown.
The relative yield of particles seems to have a relation as reported by Artukh et a1. 2 )and Diamond et al.,3) that the yield of the reaction cross section is proportional to theground -ground transfer Q - value, Qgg and the change of Coulomb interaction energy
LI Ec = (Z~ Z~
Z~)e2 /R.

-Zl

E Lab = 90 MeV
PI ,a. Spectrum

300

400

500
Channel

600

700

numbers

Fig.!. P.I.O. spectrum resulting from bombardment of 52Cr target with
90 MeV 14N projectiles.

24

(b)

(a)
50

52Cr (14N , 13 C ) 53 Mne l ob = 22°

E lob = 90 MeV
13C

50

3

E- Spectrum

6

'"

V'>

.j.J

] 25

'325

u

u

o

Channelnumbers

Channel numbers( C)
E- Spectrum
50

50

g 25

25 '3

'"c

V'>

+-'

u

o

u

Cha nn eI

50

numbers

52Cr ( 14 N, 108) 56 F e
E lob = 90 MeV
lOB

elob =20°(d)50

E -Spectrum
V'>

~ 25

+-'

25 '3
o

o

u

u

Ch anne i nu mbers

Fig. 2. Energy distributions of (a) 13C, (b) 12C, (c) lIB, and (d) lOB producedby 90 MeV

14N proj ecti les .

25

In Fig. 2 the energy distributions of (a) 13 C , (b) 12 C , (c) lIB, and (d) lOB producedby 90 MeV 14N projectiles are shown. Very diffe r ent behaviors appea r for the energy
distributions observed on the products of single proton t r ansfer reactions (13C) andthose of multi - nucleon transfer reactions ( 12 C, lIB, lOB). Only in the former, well resolved peaks corresponding to the levels of 53Mn were observed and the spectrum
shows a smaller yield in the lower energy region of 13C particles. But, in the latter
spectra, the yields a r e small at the quasi-elastic part , in which both residual nuclei arenear the ground state, and the maximum yields are observed at the positions
corresponding to about 15,...... 20 MeV excited levels of residual nuclei.
Angular distributions of six peaks for a single proton transfer reaction are shownin Fig. 3. They show small oscillations, which would be described by a diffraction
model, and the cross sections decrease monotonous ly with the increase of s catteri ng
angles. These features are not similar to the experimental data described by several
authors ,4) who showed a broad maximum for the angular distribution due to the tunnelingprocess. The angular distribution of 12 C projectiles after integration over energy
from Q =Qgg to Q = Qgg- 20 MeV is shown in Fig. 4. The angular distribution shows
little oscillation, and the yield decreases monotonously with increasing scattering angle.
This feature is the same as in the angular distribution of quasi-inelastic transfer
reaction described by Galin et a1. 4 )

G)

'I

~

52Cr(14N . 13 C ) 53 Mn

5-

E (14Nl = 90 MeV

1

J

®

~

® ~
® ~

~

"-

~

0.5

® ~

0.1

0.01

10

30

20

6 Lob

40

( deg . )Fig. 3. Angular distributions of six peaksin the energy distribution of 13C
produced by 90 MeV 14N
proj ectiles .

26

52 Cr

+ 14N (90 MeV)

100

50

~ 10

E

10

20

30

40

Fig. 4. Angular distributions of 12C
projectiles for partial energy
spectrum in the range of Qgg to
Qgg-20 MeV.

From these observations, it is supposed that in case of a single proton transfer,a direct surface interaction is the main mechanism, but in case of multi -nl1cleon
transfer a grazing collision is more dominant than the surface collision. But, as thedata are not decisive to determine the reaction mechanism, this study is to be continued
by varying projectile energy and species .

References
1)
2)
3)
4)

S. Nakajima, 1. Kohno, 1. Yamane, M. Yoshie, M. Odera, and H. Kamitsubo: IPCR
Cyclotron Progr. Rep., Q., 89(1972).
A.G. Artukh, V.V. Avdeikov, J. Era, G.F. Gridnev, V.L. Mikheev, V.V. Volkov,
and J. Wilczynski: Nucl. Phys., A160, 511 (1971).
R.M. Diamond, A.M. Poskanzer, F.S. Stephens, W.J. Swiatecki, and D. Ward:
Phys. Rev. Letters, 20. 802 (1968).
R . Kaufmann and R. Wolfgang: Phys. Rev., 121, 192 (I961); J. Galin, D. Guerreau,
M. Lefort, J. Peter, X. Tarrago, and R. Basile: Nucl. Phys., A159, 461 (I970).

27

4-2.

Selective Excitation of One Proton Configuration for

53 Mn in52Cr(14N,13C)53Mn and 52 Cr(12 C , 11 S )53 Mn

S. Nakajima,!. Kohno, 1. Yamane, M. Yoshie,
H. Kamitsubo, M. Odera, and T. Mikumo
One proton transfer reactions induced by 90 MeV 14 N and 90 MeV 12C ions on atarget of 52Cr were studied. The spectra obtained for the reactions (14N, 13C) and(12C, lIB) on 52Cr are compared in Fig. 1. Excitations of several single proton statesin the residual nucleus are enhanced for both reactions, and these reactions leave 13C
and lIB in their ground states. It is noted by comparing the spectra that relative crosssections of several peaks are very different in the two reactions. Especially the crosssection ratio [do /dQ(Ex =2.4 MeV~ / (do /d.Q(Ex = 0)] is 2.17 for the (14N, 12 C)
reaction, but it is 0.51 for the (12C, lIB) reaction (Table 1).
This feature will be explained from an angular momentum matching of thereaction)
By a reaction theory, the following selection rules are applied to thetransferred orbital angular momentum .e :where .e and j are orbital angular momenta and total angular momenta of the transferred 'nucleon in the projectile (subscript 1) and the residual nucleus (subscript 2). The
allowedtransfers for the reactions studied here are lis ted in Table 2. On the other
hand, the difference of the orbital angular momenta of the incoming and outgoingparticles at the nuclear surface AL, can be calculated for the reaction from thefollowing relations.

.e

6 L=L 1-L 2.

(1)

L1=K1R1 (1-2 1J1/K1Rl)1/2, L2===K2 L 2(1-2 1J2/K2R2 )1/2,
1/3
1/3
1/3
1/3
R1=rO(Al +A t ), R2=rO(A2 +Ar ) ,where Ll, L2, Kl, K2 stand for orbital angular momenta and wave numbers in theentrance and exit channel. AI' A2 are masses of the incident and outgoing particles,
and At, Ar are that of a target and a residual nucleus. r; 1, r; 2 are Sommerfeld
parameters of the incident and the exit channel. L1 L values of both reactions calculated
from Eqn .(l)are also listed in Table 2. The angular momentum ma tching shows thatthe cross section ratios of both reactions are probably explicable from thisconsideration. A small cross section of Ex = 1.3 MeV in both reactions is presumably
due to the fact that a main configuration of this level comes from the coupling of the 1 st
2+ state of 52Cr and the ground lf7/2 state of 53Mn, and that a component of single
particle 2P3/2 state is small.

28

50

[Lab

= 90 MeV

e

= 22°

13C

E- Spectrum

Lab .

<f)

c

:::J

0

3

52Cr (1 4N, 13C ) 53 Mn

6

25

U

0

~
500
Channelnumbers(a)

750[Lab =

90 MeV"8 Energy spectr um
500

<f)

+'

C
:::J

4

o

U

250

O L---4~O~O~~~----~50~O----------~60~O----------~------~~~8~O~
O­

Channe l numbers(b)Numbers of peaks correspond to the first column ofTable 1.
Fig.!. Energy spectra of 13 C from the 52Cr(14N, 13 C )53Mn
reaction (a) and of 11 B from the 52Cr( 12 C, IIB)53Mn
reaction (b).

29

Table 1.

Relative cross section.

(12 C, 11)B(14N, 13 C )

Level
No.

E (MeV)n 2e2 j 2 *

1

0

If7/2

1

1

2

1.3

2P3/2

0.1

0.046

3

2.4

2 P3 / 2

2.17

0.51

4

3.7

If5/2

1.7

0.715

5

4.9

1f5/2

0.74

0.195

6

6.6

3.17

0.34

x

* See Reference 2)
Table 2.

Allowed R values and calculated A L values.

52
nlRljl= lP l/2

Cr

(12

C,

nlRljl=IP 3 / 2A----------~~~---------

allowed R

E (MeV)x

allowed

36.3

4.0

4, 2

0.2

4

1.3

40.2

0.9

2

35.7

4.6

2, 0

2.4

39.7

1.4

2

35.2

5.1

2, 0

3.7

39.0

2.1

2

34.7

5.6

4, 2

4.9

38.4

2.7

2

34.1

6.2

4, 2

41.1

40.3

I

JL

40.8

0

References
1)2)11 )53
B Mn

D.M. Brink: Phys. Letters, 40B, 37 (1972).
D.D. Armstrong and A.G. Blair: Phys. Rev., 140, B1226 (1965) .

.e

30

4-3.

Gamma Transition from the First 3

levels in 94,96,98, lOOMo

T. Inanaga, H. Kamitsubo, T. Fujisawa, T. Wada,
M. Koike, and K. Pingel

Nuclear structure of even mass molybdenum isotopes has been investigated in thislaboratory by using inelastic scattering of protons, 1) deuterons ,2) and alpha -particles 3 )and also by some other reactions such as (t, p).4) In order to get further informationon the properties of low-lying levels, electromagnetic transitions between them werestudied. The E2 transitions have been extensively investigated by many authors andgave some insight on the collective nature of those le vels. This work was aimed at
mainly to measure weak E1 transitions from 3- states to lower even parity states and toobtain information on the small components contained in these states. Gamma decays
from 3- to lower 2+ and 4+ states must be E 1 or M2 transitions. In medium weigh.t andheavy nuclei, E1 transitions between low lying states are strongly hindered (about 10- 4 ----.
10- 6 of Weisskopf -unit), whereas the hindrance factors for M2 transitions are not solarge. 5 ) Indeed the hindrance factor of E 1 transition obtained in this work is about 1.7
x 10- 6 in 98Mo. Because the Weis skopf -unit for E 1 is la r ger by the order of 10 7 thanthat of M2 in this range of gamma energy, we can conclude that mos t of the transitions
from 3 - to 2+or 4+ states have EI character. It was tried to measure the absolutevalues for E1 transitions by using the particle-gamma coincidence method.
From the values of jJ obtained by inelastic scattering to the 3- states , the B{E3)values can be calculated. If the branching of the gamma transition from the 3 - level to
the 0+ ground state is observed, we can get the absolute values of E 1 transition which
decays from 3 - to 2+ or 4+ by using the above -mentioned B{E3) and branching ratios.
The 3 - levels were excited by Mo(p, P ') inelastic scattering at Ep = 14.5 MeV.
With this bombarding energy of protons, most of gamma -rays come from the decay ofcompound nucleus. Therefore the particle -gamma coincidence method was used tomake sure that the gamma radiations really decay from these 3 - levels and to reduce
backgrounds. Protons were meas ured by a Si detector and gamma rays were detectedpFig.!. Block diagram of the electronics.

31-

100000-10000f-

~
o

1000-

u

IOOf-

I
I
I
I
I
I
I
I
I
10 L---~1~
OO~--~20~0--~3~00----~~
0 --~50bO~~6~0~
0 --~70bO~~8±00~~9~O~O--~
Channelnu mb er s

Fig.2. Single spectrum of r radiation in 98Mo(p,p'r).
800
700

98 Mo ( P, p' r ) 98Mo

600

500

i

4 00

u

300

200

100

o

Fig. 3. Coincident r spectrum between r -rays and 3protons in 98Mo(p, p' r ).
2830

(4+)

2580~r&~~ 5-

2533
2421

T
( 2+)

24 50 - 2343----42208 Goa
2024 rv~ ""( 4+)

16 2 4-+-+--''---- 4+1495-+....1---- 2+1573 ___. . L - _1147-+--8 7 1 ~--

0-

-

-

777--1...-- 2+

0 - -96 Mo

~a "a

3-

1760

1910
1768

15 10
1433

4+
2.1-

1500
1463

(2+)

1140
1063

4+
2+

800
694

( 2+)
(0+)

534

2+

(0+)

2+

ot

T

1 2+

4+

2+
0+

788
736

o ~
98 Mo

0+

0+

0
l00 MoFig. 4. Low -lying energy levels and 3- branching ratio of
94,96,98,100Mo.

32

by a 50 cc Ge(Li)-counter which was placed at () lab = 90 0 in the reaction plane. Figure-I shows the block diagram of the electronics. Time pick off circuits for both particle
and gamma signals were used for the fast coincidence and the timing resolution was
about 50 ns. To measure random coincidences, the coincidence between elasticallyscattered protons and gamma rays were taken.
Figure 2 shows a single spectrum of gamma rays in 98Mo(p, p' r ) 98Mo and Fig. 3
for a coincident spectrum. Energy levels and branching ratios are shown in Fig. 4.
A transition from the 3- to the ground state is only seen in 98Mo. If we use theB(E3) = 34 ±4 s .p.u. and the transition probability for 3- - 2- , the E1 transition is T =(3.7 ± 1.0) x 109 (sec -1) and the hindrance factor is 1.7 x 10- 6 .
The coincidence spectrums have no systematic trend from 94Mo to 100Mo.
Analysis based on the nuclear structure theory in this mass range is in progress.

References
1)
2)
3)
4)
5)

T. Wada, K. Matsuda, Y. Awaya, N. Nakanishi, and S. Takeda: IPCR Cyclotron
Progr. Rep., 3, 36 (1969).
T. Wada, H. Kamitsubo, T. Fujisawa, M. Koike, and T. Inanaga: ibid., Q, 33 (1972).
K. Matsuda, Y. Awaya, N. Nakanishi, and S. Takeda: ibid., 1. 38 (1970).
S. Takeda, 1. Kohno, S. Yamaj i, K. Matsuda, N. Nakanishi, Y. Awaya, and S. Kusuno:
J. Phys. Soc. Japan, (to be published).
H Ejiri, T. Shibata, and K. Satoh: Phys. Lett., 38B, 73 (1972).

33

4-4.

by

Inelastic Scattering of Deutrons

Even Mo Isotopes

T. Wada, H. Kamitsubo, T. Fujisawa,
M. Koike, and T. Inanaga

The nuclear structure of Mo isotopes was investigated previously by inelastic
scattering of protons 1) and alpha-particles 2) by using the IPCR cyclotron. The isotopic
spin dependence of the excitation process for the first 2+ and 3- states was investigated.
In the (a, a') scattering, however the energy resolution was not sufficient to resolve thepeaks corresponding to the alpha -particles exciting the first 4+, and the second 0+, 2+
states.
The incident deutron beam from the cyclotron was first energy analyzed by amagnet and focused on the target. The incident energy was 21.5 MeV. The targets
were the same as those used in the experiment of (p,p ') and (a, a '). Scatteredparticles were detected with a counter telescope system of SSD with thickness 300 j1 m
and 2000 .am, and analyzed with an on-line computer DDP-124. 3 ) The energy resolution
was about 100 keV. Figure 1 shows an example of the energy spectrum and Fig. 2
shows the angular distribution of the scattered deutrons. As .shown in Fig. 1, the two
peaks of two -phonon like states were resolved with the aid of a computer program. The
angular distributions of the deutrons exciting the two states showed anti -phase diffraction
patterns to each other, while in case of the proton scattering they were in -phase.
Further analysis of the present experiment is now in progress.

+

N

M

300

It')

o
~

Ed =21.5 MeV

M

o

en

........
en

1

=
U

.

I

+-'

c::

:::l

u

100

_

N

I

I · ~~ _::: 1

o

o

I

I

§200

b
o

I
/.

_ .... _IIf\~~ ;-:' \f~ \ ~;~£> \ ~ .

x 1151 \: ..........
600':..:.: ···.•·:iY2:\".:.: ..J.\, ...:..

:jA~~. :. r/:\) \. \'". .: ...J \

700

800

Channel number

Fig. 1. Energy spectrum of deutrons
scattered from 100Mo nuclei.
The solid curves are the results ofleast -square fit with skewed
Gaussian.

34

1 . 0~------------------'

~V\
0.1 ~

Ed = 21 . 5 MeV\ ...........-.\'\\\ j,e\\'\\1\./."".

\

1·01-.\7\_..

•

~

III

:a

£\\

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elast i e

..
\
\1 ~
I~'\.

~
.V...... .....
.\ .
.~....."

0.1

0.777 MeV
2+

~

.~.

1.0

\

2.230 MeV.'-..!..-

MeV
fm
fm
V 100.0 1.114 0.826
Wd 14 .9 1269 0000

Vso

•••

~"

3-

29 1.114 0 .826

rc = 1.20(SEARCH ,DWUCK)
I

I

I

60°

90°

12<f'

15CP

Gem.

Fig. 2. The angular dis tributions of
scattered deutrons from 96Mo.
The solid curves are obtained by
calculation with the automaticparameter search code, SEARCH
and DWUCK.

References
I}
2}
3}

T. Wada, K. Matsuda, Y. Awaya, N. Nakanishi, and S. Takeda: IPCR Cyclotron
Prog. Rep.,~, 36 (1969).
K. Matsuda, Y. Awaya, N. Nakanishi, and S. Takeda: J. Phys. Soc. Japan (to be
published).
T. Wada, Y. Chiba, and F. Yoshida: IPeR Cyclotron Progr. Rep., Q., 78 (1971).

35

Unbound Isobaric Analog States Induced by

4-5.

50,52,54 Cr (h, d)51 , 53, 55 Mn Reactions

s. Takeda , N. Nakanishi, H. Ohnuma,
H. Toyama ,*and S. Yamada*

Experimental aspects on the isobaric analog states of 51 , 53, 55 Mn in proton
elastic scatte r ing were given by Moses et al. 1) The population of isobaric analog
states in the (h,d) reaction provides an additional information to what has been obtainedby studies of resonance reactions for the following reason . The analog states cannot be
studied in the (p ,p) and (p ,p ') resonance reactions whenever the proton energy in theentrance channel is well below the Coulomb barrier. On the other hand, in a sufficiently
high h -energy , these states can be excited in the (h ,d) reaction process.

<t

N

r---

M

f"-Nl"'- o;;t -c..D<.Dr"JO">U"lOU"lNN~~""':6o

I II i 11116:

500

52Cd h,d )53Mn
400

elab = 25°
Eh = 30 MeV

'"

~ 300

<..>
.......
Vl......
c:

3 200

Cha nnel number

Fig. 1. A deuteron spectrum of the 52Cr(h,d)53Mn
reaction at Eh=30 MeV and () lab. = 25 0 .

* Tokyo Institute of Technology.

36

A typical energy spectrum for 52Cr(h ,d) 53Mn is shown in Fig. 1. Several
strongly excited states are seen above the Q -value of 52Cr + p including the 9.30 and9.65 MeV states of 53Mn which were observed by Moses et al. 1) These two statescorrespond to the 2.32 and 2.67 MeV states of 53Cr respectively. The results for 50Cr
and 54Cr are not so much different from those for 52Cr. Angular distributions ofemitted deuterons were measured from 10 0 to 45 0 . An analysis of the experimental
result is now in progress. We are planning to investigate the population of isobaric
analog states in the (h,d) reaction and their subsequent proton decay.

Reference
1)

J.D . Moses, H.W. Newson, and E.G. Bilpuch: Nucl. Phys., A175, 556 (1971).

37

4-6.

The DWBA and Coupled Channel Analyses of
Inelastic Scattering of 3 He from 12C

T. Fujisawa, S. Yamaji , K. Matsuda,* S. Motonaga,
F. Yoshida, H. Sakaguchi', ** and K. Masui**
The experimental result and optical model analysis of the elastic scattering of 3He
from 12C have been reported previously,l) and in Table 1 the optical model parameters29.2 MeV

24.0MeV

-

C?)

_.- @

10.0

--- ®

---- (@)
'-'

~
1.0
.0
E

1.0

1.0

30

60

90

150

120

180

0

30

B C.M

=\

34 .7 MeV

-

10 .0

0)

\

- - (J)--- (jJ)\

1°°1 \
5.0

3 9 .6MeVt-ro··•.

\

t;
\..;:

I ,

y ".

\ ):;~ .......

"" _- ,

'-'

50

"
---~

..

".......
,'-' '--. "2-t~\ .. .

.~. ...

- ......

U'l

~

"

~ -->',

10.0... 2 +@-.- @- -- @\.

.......

13 2 =0.5

1.0

(d)

1 \

'",\

1.0

,- -

. ..'L--'~\~/-......

'\
\

\

b

"b

1.0

\

1.0
0.5

0. 1

o

0 .1

30

60

90

120

I SO

180

o

30

60

ISO

BC M

Fig. 1. Angular distributions calculated by the DWBA theory and experimental
values. Numbers in circles indicate the potential groups in Table 1.

***

Deceased.
Present address: Department of Physics, Kyoto University.

180142.3

135.0

24.0

29.2

34.7

2

3

4

1.1

1.1

141.2

135.1

126.5

121.2

139.9

24.0

29.2

34.7

39.6

24.0

29.2

34.7

39.6

24.0

29.2

5

6

7

8

9

10

11

12

13

14

85.26

75.1

124.2

124.6

134.0

.823

1.1

123.0

39.6

1.1

1.1

1.1

1.1

1.1

1.1

1.1

10.70

9.06

.771
.758

14.73

15.14

10.70

10.96

14.1

15.33

9.468

11.10

17.0

14.72

14.34

13043

(MeV)

Wo

.808

.793

.660

.681

.80

.784

.652

.656

.751

1.1

129.3

1.1

.700

.718

1.1

1.1

(fm)

(fm)

(MeV)

1

aR

rR

1.416

10424

1.661

1.566

1.323

1.298

1.268

1.543

1.175

1.299

10416

1.205

1.097

1.314

(fm)

rO

equal to those of real part and r R is fixed.

Optical-model parameters that gave best fits.

Vo

Incident
energy(MeV)

Potential
numberTable 1.

.773

.886

.611

.605

.882

.921

.787

.615

1.054

.911

.657

.834

.907

.823

(fm)

aO

8042

lAO

4.48

4.75

7.70

3.61

0

0

0

0

0

0

0

0

(MeV)

Vso

127.8

129.5

172.2

164 A

127.8

129.5

172.2

164.4

127.8

129.5

58.5

62.6

72.1

82.5

°max
for X2 fit

Values of a so r so are taken

62.6

88.0

28.3

43.7

53.1

67.4

37.5

62.1

74.8

71.2

11.2

17.7

4.5

8.2

X 2/N

1177

1167

1027

1034

1131

1202

1056

1033

1237

1192

1031

1091

1116

1145

(mb)

Reaction

(J

00

w

39

\

(a)

(b)

\

IXI0 2

29.2MeV24.0 MeV\.
\i _IXI0 2

B=- 0.5--- B = 0.5-.- 8 = 0

8 =- 05- -- 8 = 05

I\,L,.,."'(to \\--- 8 = 0'\ \Potent lol

Po ten t ial No.10
I XIO '

'. '

•

4

'-

.0

E

o

Ili

~

"-

L'

b

~

lXl0'

•

\ t .\\\i(\\
I' \ .

~

;IXIO

0

No. 9

\

-

'-'

if)

'-

E

-1X10o

c:::
~

\

/

.

-.: '

'

.

'

.; ' '\

/

\

I

\\

/

I I
1/

'\
'\

'"

\

'-'

..

Ground

"-

0+

b

~

/'

\

\

V

\

\

,_/

/

--o

30

60

o

180

30

60

e

\

\

(c)

150

120

90

180

C. M

Cd)
3 9.6 MeV

34 .7 MeV
B =-0.5--- B = 0. 5

- --

-

B = -0.5- -- B = 0.5--- B = 08= 0Pote nti al No . ll

Potent ial No.1 2

1XIO'

'-'

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

if)

'-

.:§ 1XIO o.

'--.-!...\\''''~.

~"0+b

Ground

0+

"

~

'",

- .,"-. .

'""'.
"- \

.

'\jC"

o

o

30

60

90

ee M

Fig. 2. Angular distributions calculated by the coupled channel theory andexperimental values. Numbers indicate the potential groups in
Table 1.

180

40

\

Ca)

\

\
\

\

\

\

24.0 MeV\.

29.2 MeV

\,;\

I

Vr\\
.

(b)

~

~

8 =- 0. 5- - - 8 = 0.5.~

8= - 0.5- -- 8 = 0.5

\

\

i

\

Potent ial No.9

\ /\

'-'
U'>

'-

Ijf\\
....C···..
! \ '~"E~ I XIOo
GroundPotentia I No. 10

0+

/

"0

-.....,
b

/

\

"0

(--.....

\I
V

I,

\

..

\

30

60

90

120

150

0

180

30

60

1Xld

7C/

90

lXl 0

1

U'>

E

-, X,0 OG\1"0-.....,b

V/\
IX10 1 -"\.. ~~ /....
-1

.

-

8 =- 0.5
0.5\1/\\. ~ .'.

·.

~\!iJ .

Ground 0 +Gro und

\

!~-

\)
V
' ... ' ........

/---

\

!

\

/

. :--:~\ / .
'. "' J .'I"'- '---...
"

\

!

2+

'I

0+

........

. \ 1/····.\) , ~. '"V....... ..

180

Potentia I No. 12

II

\ (\

150

--- 8 =

Potential No.1 1

II \ .: ........

D

"0

8=-05
--- 8 = 05

~~

"-'

'-

120

39.6 MeV

\.

\

". 2+

Cd)

\

34 7 MeV(\'."" r-- ___ / __

Se.M

Cc)

\

/

\./"" '-..JI

Se .M.

\.

.

\

....

0

•

Ground 0

'"

\J

/.~

........

~"~---...:/"/(.....2+"'-:::,.....

-....::.::.:',\-......:::,...... ~

0

30

0

60

eCM .

. . . -=- .

~~---- ......
30

60

90

120

-.....,.....~~
150- -.. . ,SCM

Fig. 3. Angular distributions calculated by the coupled channel theory andexperimental values. The depth of the imaginary parts of the potentials
are 85 %of those indicated by numbers corresponding to Table 1.

180

41

were listed. Now the authors describe here analyses of the inelastic scatterings data
based on the DWBA and coupled channel theories.
In the calculation of DWBA, the effect of Coulomb potential in the outer, region of
nucleus was taken into account, because in a preliminary calculation it was found thatthe prediction of DWBA without the Coulomb potential did not agree with experiments at
forward angles. The dis tortion of s pi n -orbi t potential was of the full Thomas typeproposed by Sherif and Blair 2 ) and its value was taken equal to that of real and ' imaginary
potentials. In Fig. 1 the calculated values by DWBA are shown with experimental
values. In all the analyses, the potentials with the spin-orbit coupling gave a larger
yield than those without the spin -orbit coupling. We can see a difference between thetwo potentials but cannot say which is better, because the fits are not exact. The
values of fi2' fi3' and ji4 are about 0.5, 0.4, and 0.22 respectively. It seems that the
deformation parameters fi 2 and fi 3 are too large for the perturbation theory. If wewant a more exact calculation, we must consider the coupling between the states.
Formalism of a coupled -channel calculations was presented by Tamura and others
and applied successfully to nuclear reactions.3)"-' 7) A coupled -channel analysis of theground and the first 2+ states was tried ass uming the latter state as a rotational band.
In a preliminary calculation, it was found that the effect of Coulomb potential improved
the fit at forward angles and the complex form factors were better than the real ones;
so in all the analyses the form factors were taken complex and the effect of Coulomb
force was included. The assumed values of the coupling coefficient;92 were t 0.3,
to.5, and ±0.7 in the preliminary calculation, and it seemed that the best value was- 0.5. Figure 2 shows the predicted curve by the coupled -channel calculation using theoptical parameters that gave the best fit for elastic scattering. It is remarkable thatthe predicted elastic scattering cross section was changed appreciably by coupling to
the inelastic channel. 1 ) According to our spin flip experiments of 3He -particle which
excited the first 2+ state of 12 C and the collective DWBA analysis, the spin orbit
potential, of which the depth was shallower than that of the best fit potential, gave better
fit to the spin flip probability.8) Therefore, the calculation with the optical potential, of
which the spin - orbit potential depths were 3.5 and 2.5 MeV, were carried out at 39.6
MeV, but the situation was not improved.
It seems reasonable that the depth of imaginary part of the optical potential in the
coupled - channel analysis is shallower than in the optical model analysis only of elastic
scattering, because the imaginary part means the channel other than the elastic channel
and in the coupled -channel analysis the inelastic channel has been included already.
The authors found that it is better to take the depth of imaginary potential at about 85 %of the depth given by an optical model analysis. The results are shown in Fig. 3. We
see that the elastic channel as well as the inelastic channel is improved and that thenegative value of;92 gives better results at 34.7 and 39.6 MeV. The other authors also
reported that the sign of;92 of 12C was negative in the coupled-channel analysis of the
12C(p,pt) 12C reaction or the analysis of the 12c(a, at) 12C reaction with the theory ofAustern and Blair. 6 ), 9)
In the analyses FACOM 270/30 and 230/60 computers were used.

References
1)
2)
3)

T. Fujisawa, H. Kamitsubo, S. Motonaga, K. Matsuda, F. Yoshida, H. Sakaguchi
and K. Masui: IPCR Cyclotron Progr. Rep.,
46 (1970).
H. Sherif and J.S. Blair: Phys. Letters, 26B, 489 (1968).
T. Tamura: Rev. of Modern Phys., 37,679 (1965).

±,

42

4)
5)
6)
7)

8)
9)

R.L. Robinson, J.L.C. Ford, Jr., P.H . Stelson, T. Tamura, and C.Y. Wong: Phys.
Rev., 187, 1609 (1969).
N. Lingappa and G.W. Greenless: Phys. Rev., C2, 1329 (1970).
O . Mikoshiba, T. Terasawa, and M. Tanifuji: Nucl. Phys., A168, 417 (1971).
T. Tamura: ORNL -4152 unpublished computer program Jupiter 1 for coupledchannel calculation; M. Wakai, S. Igarashi, O. Mikoshiba, and S. Yamaji: JAERImemo, P. 3833 (1969).
T. Fujisawa, S. Motonaga, H. Kamitsubo, Y. Chiba, and T. Wada: IPCR Cyclotron
Progr. Rep., ~, 44 (1971).
J. Specht, G.W. Schweimer, H. Rebel, G. Schatz, R. Lonken, and G. Hauser:
Nucl. Phys., A171, 65 (1971).

43

4-7. 20Ne(d, 6Li) 16 0 Reaction

M. Odera, S. Takeda, and S. Nakajima

20Ne(d, 6Li) reaction was investigated as a part of study of the a pick -up reactions
from s-d shell nuclei)
The energy of deuteron was 23.5 MeV. The pressure in thegas target was read by an a -tron gauge .2) The absolute value was obtained using a
conversion factor for neon given in the manual of the gauge. The pressures in thevicinity of 50 Torr were used throughout. The Q -value of the reaction is - 3 .26 MeV.
The particle identification system was described previously)
Figure 1 shows the spectra from neon and oxygen and Fig. 2 shows the angular
distributions obtained. The 6.03 MeV 0+ and 6.14 MeV 3 - states of oxygen were notresolved. Unfortunately, in the peak corresponding to 6.91 MeV 2+ of 16 0, those peaks
from 1.98 MeV 2+ of 18 0 originated from 22Ne and from 4.43 MeV 2+ state of 12C
originated from 16 0 seem to be mixed. Lack of oscillation of the angular distribution
may stem from this mixing.

Ic:.

Ne(d 6 LilO

<;j

100

20°

0
+
C\J
~

<J>

0

+
0
<.0

6000jlC

16100

0 (d, 6 Li )12C
20°

2,OOO,uC

0

0

.9 ~
Q.)

z

0

N

Q.)

z

~

-0

o

c:
'--

0'

a;

<->
~t

C
C

0
£

o

°-.. . . 50

<D

~
C

::l
0

°
-0
C

'--

0'

-0
C

'--

0'

P

<Do

Q.)

<Do

Z
N
N

oL----3~0~0----4~0~0--~~~~~~~~

Channels

Fig.!. (a) 6 Li spectrum of Ne(d 6Li)0
reaction at laboratory angle of
20 0 .

Channels

Fig. 1. (b) 6 Li spectrum of 160(d 6 Li )1 2 Creaction at laboratory
angle of 20 0 .

44

2°Ne (d, 6 Li )16 0[(d) =24.0 MeV

100

2°Ne (d 6 Ld 16 0 grnd
Effect of Li potentio l

V
W
(0
r;
r;;
ao a,
Bethge: 37.8 8.07 1.42 \.90 2.50 0.95 0 .62~--- Denes: 126.8 24 .9 1.18 2.5 2.0 0.810.90

501000 "\(eN= 2.0 a = 0.6
Energy quanta 8

\

..:

\

<J>

\

'-

:3- 100

separation 4.73 Mev

\
\
\
\

E

u

-

\

~

-

\

100

\
\

\

'_I

100
10
50

o

10

20

30

40

50

60

Bc.m.

Fig. 2. Experimental angular distributions obtained for
20Ne(d 6 Li) 16 0 reactions.
Numbers for each curve
indicate the states of residual
16 0 nucleus.

Fig.3. Zero-range DWBA fit of theground state transfer. Effects of
Li potential are compared.
Optical parameters of the deuteronchannel are V = 92.2, W = 35.8,
rv = 0.965, rw = 1.46, a v = 0.89,
a w = 0.813, rc = 1.30.

Figure 3 shows the zero -range DWBA fit of the ground state transition based on
the Simple-minded a cluster transfer assumption.1),3) Fit of 2nd peak assuming pickup from p -shell has failed completely in this simple prescription.

References
1)
2)
3)

M. Odera, S. Takeda, and 1. Kohno: IPCR Cyclotron Progr . Rep . , 1,.29 (1970).
Alphatron type 820. Norton Vacuum Equip. Di v. 160 Charlemont St. Newton.
Mass. USA.
L.J. Denes, W.W. Dehnick, and M. Drisko: Phys . Rev., 148, 1097 (1966).

45

4-8.

Ine las tic

Scattering for the Giant Resonance States

H. Kamitsubo, T . Wada, T. Fujisawa, T. Inanaga,
M. Koike, and T. Mikumo

Recent experiments 1) of electron scattering at Tohoku University have shown an. evidence for the excitation of the giant resonance states of dipole and quadrupole type inclosed shell nuclei. They have also observed that many states above 10 MeV were
(a )

1500

40Co ( p,p')

16°

5 1.9MeV

18jlc.

1000
C/)

-+--'
C

:::l

o

U

1000

(b)

40Co ( p, p' )16°

5 1. 9 MeV
60}K

(J)

l[)

(")

q

I

~

l[)

u-i <i

C/)

~ 500
:::l

o

U

=ii>
~

~

~

250 MeV 50°

if'o,= 0.5
w

-0

c:
-0

N'b

'-'-'-'-'-0

Exci ta tionenergy(MeV)

Fig . 1. Energy Spec tra of 52 MeV protons from 12C target . They weremeas ured at two different field strengths of the particle
analyzer (a and b). One of the elec tron spec tra obta ined at
Tohoku University is also shown for compa rison (c) .

46

excited strongly and most of them seem to have E2 character. In this laboratory, we
made a plan to study these states by means of inelastic scattering of 50 MeV alphaparticles from the cyclotron and also 52 MeV protons from the FM cyclotron at INS,Tokyo University, for the purpose of obtaining more definite information on thesestates.
It was shown 2 ) that by comparing results of the inelastic scattering of protons andalphas, one can get spin flip and iso -spin flip components in the transitions to thosestates. It is also expected that we can determine their spins, parities, and reduced
transition probabilities from angular distribution measurements by applying a correct
distorted wave approximation. 3 }However there are some difficult problems in obtaining accurate inelastic
scattering cross sections for such highly excited states. In the particle spectrum overthe energy range of our interest, backgrounds due to a weak stray beam can be added.
Therefore the beam must be carefully aligned and a slit system must be used. Also
low energy particles scattered by the contamination of light elements in the target
become large sources of errors. In the a -scattering experiments with some target
elements, large peaks due to the in -flight decay of SHe and 5Li formed in the pick -up
process was observed in the same energy range as the giant resonance states .4)
We measure energy-spectra of 52 MeV protons from 12C, 40Ca, 51V, Cu(natural),and 208Pb in order to examine the above technical and physical problems. The
scattered protons were detected with the INS particle analyzer system. We observed
the broad peaks which correspond to the giant resonance states in 12C and 40Ca but
could not obtain any positive evidence of the excitation of those states in other nuclei.
These spectra are used as the standards for the a -scattering experiment. Figure 1
shows the proton spectra from a Ca target. The electron spectrum obtained at Tohoku
University is also shown for comparison. Above 10 MeV one can see many sharp peaks
and some broad ones, most of which are also observed in electron scattering. Further
study by 52 MeV protons and 50 MeV alphas are in progress.

References
1)
2)
3)
4)

Y. Torizuka, y. Kojima, T. Saito, K. Itoh, A. Nakada, S. Mitsunobu, M. Nagao,
K . Hosoyama, and S. Fukuda: Proc. lnt. Conf. Photoreaction, Sendai (1972).
Y. Awaya, K. Matsuda, T. Wada, N. Nakanishi, S. Takeda, and S. Yamaji: J. Phys.
Soc. Japan, 33, 881 (1972).
G.R. Satchler: Nucl. Phys., A195, 1 (1972).
G. Chenevert, N.S. Chant, 1. Halpern, C. Glashausser, and D. L. Hendrie: Phys.
Rev. Letters, 27,434 (1971).

47

4-9.

Effect of Exchange Currents on Orbital g-Factors

S, Yamaji,

M. Hirata, * and J . Fujita**

Recently a simple relation was derived by the authors between the change oforbital g-factors due to exchange currents and the sum rule for El photoabsorption on
the basis of an assumption that the momenta of nucleons inside a nucleus have theFermi -type distribution ;1)2 (Ogl) exch. = x. (=0.4) for N= Z,

Inwhich x. is defined by~a r(El)dw= (7r~A/2M) (l+x.)
The purpose of this note is to reexamine the validity of the above relation by useof a shell model. In Table 1 the res ults of the zeroth -order shell calculation are shownfor hw = 41 A -1/3 MeV.
Table 1.

(For Rosenfeld mixture, we use V = -28 MeV and rO = 1.414 fm)

Nuclear force
Nucleus

*

**

,

OPEP

Rosenfeld

A

~

ogg

x.

og.e

x.

15N

p 1/2- 1(p)

0.116

0.196

0.232

0.393

170

d 5/2

(n)

-0.0640.199-0.1290.399

39K

d 3/2--l(P)

0.108

0.196

0.217

0.395

41Ca

f 7/2

(n)

-0.0690.199-0.139

0.399

87Sr

g 9/2 - 1 (n)-0.0680.187- 0.137

0.375

89 y

p 1/2

(P)

0.160

0.187

0.320

0.376

89y

g 9/2

(P)

0.083

9 1Z rd 5/2(n)-0.0870.188-0.1750.377

207 Pb

P 1/2-1(n)-0.1220.183-0.244

0.367

209Bi

h 9/2

(P)

0.099

0.183

0.199

0.367

0.166

Department of Physics, Hiroshima University.
Department of Physics, Tokyo University of Education.

48

From this Table we can draw several conclusions that a) the relation xl I age 1'.2
holds approximately; b) the one-pion exchange potential (OPEP) explains only half of the)(exp. ~ 0.4; c) for heavy nuclei, the isoscalar part of age is important.
The point b) arises from the fact that the central space -exchange part of the OPEP
is weaker by a factor of 2 than that of the phenomenological nuclear potential such as
the Rosenfeld force which can explain that x :::::=0.4 . However, it should be noticed thatthe tensor part of the OPEP is partly changed into the central potential as the secondorder effects;V

ef f
2 <VT2)'= ( rr)P
central
L1 E
triplet.

It is already known 2 ) that the effertive value of the energy denominator is about 240
MeV. In order to study this effec .. , we carried out the first-order perturbation
calculation for the configuration mixing with 2 hwjumps. The results are shown in
Table 2.
Table 2
Nucleus

17 0- 0.0016

0.011- 0.00022

0.011

Actually the effect of configuration mixing due to tensor forces is seen to be small in so
far as the lower levels are concerned.
Finally it should be remarked that, in order to compare our results withexperiments, we must subtract the second -order effects (mainly normalization effects)( age)' from the above ( 0 g e)exch.

References
1)
2)

J.I. Fujita and M. Hirata: Phys. Letters, 37B, 237 (1971);.
J.I. Fujita, S. Yamaji, and M. Hirata: J. Phys. Soc. Japan, 33,541 (1972).
G.E . Brown: "Unified Theory of Nuclear Models", 2nd. ed ~North - Holland,
Amsterdam (1967).

49

4-10.

Total Energy Surface for

236 .

U

In the Two-Center Models. Yamaji, S. Suekane, *and K. Harada * *A two -center model has recently been developed by Greiner et al. 1 ) ~ 5) Thismodel allows a smooth transition from the ground state of one nucleus to a system of
two completely separated fragment nuclei and is suitable for the __description of fission
phenomena.6)~ 8) We have made the computation code for the model including thespin -orbit interaction and by using it we have calculated the total energy surface for
236U.
The Hamiltonian of this model is

where

4 -1/3 (1+-0·)2
1/ 3 (i= 1, 2) ,(1--0.)3 I
3 I
23 (3·-1
0i= 2 2112+1 (i=1,2 ),

o
w.
=w.

10

lZ

(2)

(3)

I

W:fJ

W:Z ,

( 4)

Six shape parameters <VIP' <V 2fJ , <VIz' (lj2z' zl' z2 are expressed with the deformation
parameters of fragment nuclei ft 1 and ft 2, the center separation zo' the mass ratio
a~=Al/A2)' the mass of the parent nucleus A, the nuclear radius parameter rO and theoscillator parameter &0 by the following six conditions:(i)

The nuclear surface is continuous at the matching plane z = O.

(ii)

*
**

( 5)

(iii)

The volume conservation is applied for the equipotential surface thatcoincides with the nuclear surface.

(iv)

The volume ratio is equal to the mass ratio a .

Osaka City University.
Japan Atomic Energy Research Institute.

50

(v)

1 1 = (VIP /(vi)

1 2 = (V 2fJ / UJ 2z .

(j)

1z.

This Hamiltonian is solved by diagonalization in the basis of eigenstates of acorresponding two-center oscillator potential that meets the requirement
2 _UJ fJ -

2
( (j) IfJ

+ UJ 22fJ ) / 2,
z~ 0

(6)

z< O.
The notations niz' np, nq; of Eqn. (1) are used for quntum numbers of eigenstates of Eqn.
(6 ).
The total energy E tot is given by
E tot = Es + Ev + Ecm + Ec

(7)

where E s ' E v , and Ecm are the simple sum, the virial term and the correction of thecenter-of-mass motion. They are expressed as follows.
(8a)

(8b)

--

IPl.F21E em = - A ( ~ t A+ ~ <<P Aq; fJ. 2 m q; AcP f1-> an ts ym ) .
1 oee

oee

A

AfJ.

(8c)

Coulomb energy Ec was calculated by Beringer's method. 9 ) The notations € Aand ¢,,{ stand for the eigenvalue and the eigenfunction of Eqn. (1), and t,,{ represents the
expectation value of the kinetic energy operator p2/2m of the eigenstate ¢ A .
The total energy surface for 236U was calculated in the frame -work of thesymmetric two -cente r model. The energy surface in this symmetric case can be shownin a two-dimensional representation as a function of two parameters 1 (= ft 1 = 12) andzO' The nuclear radius parameter rO and the oscillator parameter n &owere taken tobe 1.2 fm and 41 A - l/3 (= 6.63458) MeV, respectively. The values of the spin-orbit
parameters K and /.1 are the same as those of Ref. 4). The diagonalization was
performed with single particle states which had the principal quantum number N < 10.
The total energy surface in the case of 0 = 0.0 is shown in Fig.!. The correction
term Ecm was not calculated.
It is see ~ n that the present calculation reproduces the experimental fission barrierheight (Ebar = 5.8 MeV) fairly well. The virial term Ev plays an important role ingiving a reasonable barrier height, though the result of Albrecht et al. 4 ) whichcorresponded to (Es + Ec) ga ve too high barrier height. This conclusion was pointed
out by Maharry and Davidson 7 ) and also obtained by our exact treatment of the spinorbit interaction and the 2 term.
In order to see the behavior of the terms Es and Ev in the cases of 0 = -0.3 8, 0.0,
0.38 the magnitude of each term is shown in Fig. 2, separately. In Fig. 3, the total
nuclear energy surface is shown as a function of two parameters 0 and z00

e51

Symmet r ic fission of

236U

5 =0.0

950.0

200.0
Total

energy

~

~

'"

'"
'"

~

~

.0

~ 900.0

g

150.0

U

f
Fig. l.

"0
0

0

0-

c:

'"

0

f-

100.0~~ 850.0...-::.......----:::j 50.0

800.0

The energy surface of 236U in thesymmetric two -center model.
The total nuclear energy which isthe sum of the terms E s ' E v ' andEcm at Zo = 3.0 fm was set to be
0.0 MeV. The term Ecm wasneglected. Coulomb energy wascalculated with the assumptionthat the density distribution was
the same as the two-center
potential.

Zo (fm I(MeV )

T : Total nucl ear energ y

250.0

S : Simp le sum
V : Viriol corr ecti on

I

\

I

I

200.0

\

i

/

\
\

\

_ ____ ___ 1 _____ __\\,,--.----

\

S

"""
150 .0'" -\--- - -------------\

S\.

y._._--S ' .---

/"\
/

""'V
."-...

__

j.

-y-- ---- ---v.__--- - 0=-0.38

Fig. 2.

------- <5 =0 ,0_. _ - 6= 0.38

The total nuclear energy and its
components, the simple sum Es
and the virial term Ev'
Zo (fm)

52

100.0

>-

c>

IQ)

C
Q)

I-

o

Q)

u

250.0

o.

5.0

10.0

15.0

2 .0

Fig. 3. The total nuclear energy surface
as a function of the deformation
parameter of each fragment
nucleus 0 and the center s eparation zO'

As the second barrier has disappeared in inclusion of the Coulomb energy Ec as
is seen from Fig. 1, a more careful treatment of the Coulomb energy seems to benecessary. The study of the nuclear fission based on the asymmetric two-centermodel in which the potential shape is improved by rounding the neck is now in progress.

References
1)
2)
3)

4}
5}
6)
7}
8}
9)

P. Holzer, U. Mosel, and W. Greiner: Nucl. Phys., A138, 241 (1969).
D. Scharnweber, U. Mosel, and W. Greiner: Phys . Rev. Letters, 24, 601 (1970).
K. Albrecht, D. Scharnweber, W. Greiner, and U. Mosel: Phys. Letters, 32B, 229(1970).
D. Scharnweber, W. Greine r , and U . Mosel: Nucl. Phys., A164, 257 (1971).
U. Mosel, J. Maruhn, and W. Grei ner: Phys. Letters, 34B, 587 (1971) .
U. Mosel and H.W. Schmitt: Nucl. Phys., A165, 73 ( 1971).
D .E. Maharry and J.P. Davidson: Nucl. Phys., A183, 371 (1972).
M.G. Mastafa, U. Mosel, and H.W. Schmitt: Phys. Rev. Letters , 28,1536 (1972).
R. Beri nger: Phys. Rev., 131,1402 (1963).

53

4-11. On the Mechanism of

C3 He, t)Reaction

M. Toyama

A number of experiments on the (3He, t) reaction have been done recently andinteresting facts have been pointed out. In particular, the exci tation of isobaric analog
of the target ground state (hereafter referred to as GIAS-excitation) has beeninterpreted with apparent success by means of DWBA with quasi -elastic charge exchangemechanism. However, the DWBA analyses of other (3He, t) reactions on the assumptionof charge exchange mechanism exhibited many serious problems.
(1)
A very large deformation parameter for the Lane potential is needed inorder to account for the scattering to excite the analog of the first excited 2+ states of
the target nucleus 1) (hereafter referred to as 2+ IAS -excitation).
(2)
The strength of the iso -spin part of the effective two -body interaction isrequired to depend strongly on the transferred angular momentum, It, in order toaccount for the magnitude of the observed cross section for exciting the configuration
states),3)(3)
For the excitation of anti-analog states, the positions of peaks and valleys
in the angular distribution disagree entirely with the calculated ones .4)<(4)
GIAS -excitation was observed at a few energy pOints and analyzed by DWBA
using microscopic form factors .5) The strength of the two-body interaction potential
needed to account for the observed magnitude of the cross section is strongly dependent
on the incident energy.
These problems cast serious doubt on the applicability of a conventional DWBA to
the analyses of (3He, t) reactions. Alternative mechanisms have been proposed to savethe difficulties . For the firs t problem it was pointed out that the two -s tep process via
the first excited 2+ states or the analog state of the target ground state is important .6)--8)
For the second and the third problems it was found in case of 48Ca (3He, t) 48S c or
40 Ar (3He, t)40K that the two -s tep proces s, (3He - a - t), is i mportant. 9 ) ~ 11) In thisprocess the projectile picks up a neutron to become an a -particle in the first step andthen the a -particle is stripped of a proton to become a tri ton which is emitted. In theRef. 9), 10), and 11), it was also pOinted out that the two-step process , (3 He - a -t ), is
important even in the quasi -elastic scattering. For the fourth problem the DWBA
analysis with a complex effecti ve potential gives an agreement with the observed crosssecti ons .1 2 )The purpose of the present paper is to investigate the (3 He - a -t) mechanism
further, especially to answer the following questions.
''- A. In the excitation of configuration states, is it generally true for any target that theIt dependence of the potential strength required in the DWBA fitting for the experimentis mostly due to the (3He- a-t) process?
B. Do the cross sections of GIAS -excitation due to the two-step process, (3He - a -t),have the proportionality to the number of excess neutrons, (N-Z)?
C. Can the magnitude of observed cross sections of GIAS -excitation be accounted for54

if the coherent sum of the DWBA and (3He- a -t) amplitudes are used for the scattering
amplitude?
D. Can the energy dependence of the potential strength in DWBA with a real reaction
potential be removed by taking into account the two-step process?
In this paper these problems are investigated by analyzing the data on 46,48,50 Ti(3He, t)46,48,50V at E3He = 24.6 MeV,13) 90Z r (3He, t)90Nb at E3He = 21.7,29.7, and37.5 MeV,5) and 90Z r (3He, t)90Nb at E3He = 2114) and 37.7 MeV3) using the second
order perturbation theory for calculating the (3He- a -t) process .9) In the Ref.
7)and 9), a perturbation method is used. According to the Ref. 8) and 11), thedifference in the numerical res ults between the perturbation method and the coupledchannel method is not large for these reactions.
In these calculations, the Blott-Jackson potential of Gaussian type l5 ) was used as
the effective nucleon -nucleon interaction for the DWBA term. The normalization factor
Do in the zero - range approximation for the two-step process was taken to be that given
by ReL , 16) obtained from the analysis 5 4 Cr(3He, a) 53Cr at E3He = 18 MeV.
The results of calculations are shown in Figs. 1 through 4. In each of thesefigures, the dotted line represents the calculated cross section given by the DWBA term
only and the broken line represents the one given by the two-step process, (3He - a -t),only and the full line represents the coherent sum of the two. These seem to indicatethat the two-step process, (3He-a-t), is the main process in some of the (3He, t)
reactions. The answers to the questions A through D seem to be the following:
t'
10

+i
1
I
I
I
/

/

"

_/

J28 •..

~

o.

~

40

50

Itt

; It tt t t

ft +; ;

+

In,

6'

0.1

C.1

10

20

10

20

30

60

70

Fig.!. Differential cross sections for the 90Z r(3 He , t)90Nb(2+, 4+, 6+, 8+) reaction at
E3He = 21 MeV. The dotted line
represents the calculated cross section
given by the DWBA term only and thebroken line represents the one given by
the two -step process, (3He- a-t), only,
and the full line represents the coherent
sum of the two.

55

Zr 90( He 3, t ) Nb 90

Eh=37.7MeV,,,
I

lOr ""~~ t~===========:
10
\

\

,....

...... "\"-'--',...............

Q1

Fig. 2. Differential cross sections for the 9 0 Z r (3 He ,t)9~b(2+, 6+, 8+) reactions at E3= 37.7MeV.
He

A'. In the excitation of configuration states with even spin, it is true not only for
48Ca(3He, t)48S c but also for 90Z r (3He, t)90Nb that the It dependence of the potential
strength required in the OWBA fitting for the experime-nt is mostly due to the (3He-a -t)
process.
BY. The cross sections gi ven by the two -step process, (3He- a-t), for GIAS -excitationis roughly proportional to the number of excess neutrons, if the ground state of thetarget nucleus has valence nucleons only in the single j orbit outside a closed shellcore.

c' . The magnitude of obse rved cros s sections in G IAS -exci tati on is accounted for by
the coherent sum of the OWBA and (3He- a-t) amplitudes, if the Blott -Jackson potential isused for the two-nucleon potential in the OWBA term.
0 ' . The energy dependence of the potential strength in OWBA is reduced by taking into
account the two-step process. The cross section, however, is sensitive to thepa rameter of the optical potential and the value of Do. Experimental data on 90Z r(3 He,
3He)90Z r , 90Z r (t, t)90Z r , 90Z r (a,a)90Z r and 90Z r (3 He , a)89Z r at each energy are
not sufficient to decide the optical potentials and Do, making it difficult to draw definite
conclusions .

56

1eo

T iC Hg. t ) V
Eh-24.6 ~7

10

20

30

Be.M.

Fig.3. Differential crosssections for the 46,48,50Ti(3 He ,t)46 ,48 ,5Ov(GIAS)
reactions at E3= 24.6
He
MeV. F or the symbols
see Fig.!.

SC.M.

Fig. 4. Differential eros s
sections for the 90Z r (3He ,t)90Nb(GIAS) reactionsatE3H. e =21.4MeV,29.7
MeV and 37.5MeV. For
the symbols see Fig. 1.

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

G.R. Satchler, R.M. Drisko, and R.H. Bassel: Phys. Rev., 136, B637 (1964); P.O.
Kunz, E. Rost, R.R. Johnson, G.D. Jones, and S.I. Hayakawa: ibid., 185,1528 (1969).
P. Kossani-Demay, p. Roussel, H. FaraggL and R. Schaeffer: Nucl. Phys., A148,
181 (1970); R. Schaeffer: ibid., A158, 321 (1970).
S.I. Hayakawa, W.L. Fadner, J.J. Kraushaar, and E. Rost: ibid., A139, 465 (1969).
R. Hinriches, R. Sherr, G. Crawley, and 1. Proctor: Phys. Rev. Letters, 25,829(1970).
W.L. Fadner, J.J. Kraushaar, and S. I. Hayakawa: Phys. Rev., C5, 859 (1972).
W.E. Frahn and G. Wiechers: Nucl. Phys., Al13 ,593 (1968).
M. Toyama and N Onishi: Prog. Theor. Phys., 47 ,460 (1971).

57

8)
9)
10)
11)
12)
13)
14)
15)
16)

V.A. Madsen, M.J. Stomp, V.R. Brown, J.D. Anderson, Louisa Hansen, Calvin Wong,and J.J. Wesolowski: Phys. Rev. Letters, 28 , 629 (1972)
M. Toyama: Phys. Letters, 38B , 147 (1972).
R. Schaeffer and G.F . Bertsch: ibid., p. 159.
W.R. Coker, T. Udagawa, and H.H. Wolter: ibid., 40B, 49 (1972).
W.L. Fadner, J.J Kraushaar, and S.l. Hayakawa: ibid., 40B, 49 (1972).
P.G. Roos, C.A. Ludemann, and J.J. Wesolowski: ibid., 24B, 656 (1967).
R.C. Bearse, J.R. Comfort, J.P. Schiffer, M.M. Stautberg, and J.e. Stoltzfus: Phys.
Rev. Letters, 23,864 (1969).
J.M. Blatt and J .0. Jackson: Phys. Rev., 76 , 18 (1949); e.w. Wong and e .Y . Wong:
Nucl. Phys., A91, 433 (1967).
R. Stock, P. Bock, P. David, H.H. Duhm, and T. Tamura: Nucl. Phys., AI04, 136(1967).

58

4-12.

Coupling between Valence Nucleon and

Clusterized Core

N. Takigawa

The structure of 9Be is studied to clarify the situation of coup Ling between avalence nucleon and the clusterized core)
We examine this problem on the basis ofvariational principle by taking a microscopic model. We assume such variational
passes that allow the nucleus to have a cluster structure consisting of either a valence
neutron coupled to a clusterized core, or a - and SHe particles, and in an opposite limitof variation to have such structure that is suggested by the intermediate coupling shellmode1. 2 )At the outset, we assume that the valence neutron is coupled strongly to the core;i.e. that the Hartree Fock field can be defined in the total sys tern, because there appears
experimentally a strong coupling type of ground state rotational band with negative
parity. The following trial wave functions, which are based on the LCCO approximation,
will be appropriate to represent such a picture of strong coupling:

with
1

fPsM

+ a+dgn!.
+ a +
+ a +
+ a +
+ i a dull!.
+ a dup+ i a duP!.
+> Int.= a +dgni
dgpi
dgp!.
dun
0>.
I

Each single particle wave function is assumed to be expressed as a linear combinationof low -lying cluster orbitals around two cluster centers, which are denoted byparameters d and d ~ , for example,

1

Idt> = Ndt{ex p[ -z~2(r-dD2]+exp[ - z~2(r-d~) 2]}
l7ru(M Q=l) > = - ~( l7r ux> +il7ruy»
with

It is assumed tentatively that d~ = dr = (O,O,-d/2) and d~ +d'~ = 0.

a;O.N.

(2). > is the second one with lable (Jrepresentatlon.

t,

The wave function
and is orthogonalized to the first

a;

where
with

Idt(Z»=Ndt(Z){(Z-df3) ex p[ -Z~2(r-dn2]-(Z-d~3) ex p[ -Z~2(r-d2)2]}.

It can be shown easily that the wave functions I <l> ~>,I <l>~>,and

I<l>~ > coincide, in the59limit of without clusterization (of d being zero), with the shell model states (000)4(001)4

A{(100)+i(010) }, (000)4(001)4(002) and (000)4(001)4, labelled by the oscillator quanta in

x ,y, and z directions.
Our variational Hamiltonian is given by

where TC.N. is the operator of the center of mass motion. We assumed two types ofeffective interactions; Volkov force no.l with Majorana strength m =0.60 and Hasegawa
and Nagata force No. 1. 3 ) All of the qualitative results were found to be consistent inboth cases, although some quantitative discrepancies were observed. The former
interaction gives larger equilibrium values of band d, but both interactions will givealmos t the same spectros copic factor, because it is a function of the ratio d/b. The
Volkov force gives 9Be less binding energy than 8Be mainly because it cannot give
sufficient binding energy to odd system SHe.
Figure 1 shows the variational energy surfaces in these states as functions ofparameter d. The figure includes, for comparison, the energy surfaces in the states

[ ltU

o
- 10
_ _ _ [(J:

-20

[(Jt

-30 -

-40
-20

lLJ

-30

- 40

0,0

1,0

2,0

3.0

4.0

50

6.0

d

Fig. 1.

Energy surfaces as functions of the degreeof clusterization d. The parameter b was
fixed to 1.S fm, which gives the energy minimum
for the state I <l> ~ >. The index N denotes thecurve is for the state I <l> ~ > and so forth. Theenergies were calculated by use of Volkov
force no.2 with m=0.60. In the upper half, thesingle particle energy spectrum is shown as
a function of d to show the effect of c lusterization.

60

of 8Be with maximal and lower spatial symmetries.
defined by

The wave function of the latter is

with
+
-- +
1 1
I
1 1
I
X+( [431] 131'( ) = ~(SaSPTaTP)a1'(u(M£=1) SaTaaduSpTp<
22SaSp 1-1> < 22TaTP 00>.

-- b
40

>

d~

\

20

deu

\

____ d v

~.

Q)

.\

~

~ ..

/

.~
'::::il

~//
~~
---"

/

25

... :;;.--

{>

{>
0.0

1.0

/

'"

\V

45

/

-........

\ .\
"

Lu

1.3

1.4

1.5

1.6

2.0

3.0

4 .0

5.0

6.0

0 .0
(1.0)

1.5

1.6

1.7

1.8

1.0
(2.0)

2.0
(3.0)

3.0
(4 .0)

4.0

b

5.0d

(d~ )

35
35

>

Q)

---- d V

~

40
40

~

45
0.0

10

Fig. 2.

{}

1.4

1.5

1.6

2 .0

3.0

4 .0

5.0

6.0

0.0

1.0
(0.0)

2.0
(1.0)

1.4

1.5

3 .0
(2.0)

4.0
( 3.0)

Energy surfaces as functions of the parameters
band d. The solid line was obtained by varyingb and choosing the other parameters so as togive the energy minimum. The other lines wereobtained similarly. The arrow indicates thevalues of parameters, which give the lowest
energy in each state.

1.6 b
5.0d

(4 .0) (dg)61

We see that a large degree of clusterization in the state 1<I>~>persists stably in the
nucleus 9se, although some change of it (somewhat reduction in the negative parity state)is caused by adding a valence neutron. This is contrary to the situation in the state
I<I>~ > , where clusterization is much reduced (b becomes larger and d becomes smaller)
by an additional valence nucleon and a hole in the core.
This finite degree of clusterization in the nucleus 9Be will explain the energy gap
between two peaks observed in the (P,2p) reaction,4} which becomes smaller in thisnucleus in comparison with the general trend in the surrounding nuclei, because theinverse of this gap is proportional to the time during which a nucleon is trapped by adefinite side or cluster of the total system. This proximity in energy of two single
particle levels is mainly caused by missing of gap in kinetic energy in these states due
to large clusterization. Similar effect through the kinetic energy appears in proximityof total energies of states with negative and positive parity. We may have a better
variational wave function by varying independently the parameter d in each single
particle orbit. Figure 2 shows such energy surfaces that are obtained by varying aparameter, say b, and by taking values of all the other parameters so as to give thelowest energy at each value of b. We see there quantitative refinement, but noqualitative change.
We can take another type of variational wave function if we allow the parameterVd in the wave function of valence nucleon to have a different value from that ofclustering parameter of the core dC,\~~ > S'. Int.

=a+O"t 6 (2/) n.i \ ~~ >N

Int. ,

where the single particle wave function is defined by\O"to. N.(2/) > = N O"to.N.(2/) {\O"t(2/) > - < O"t(2' )\O"t > \O"t > }with

Our new trial wave function 1<I>~>S'.Int coincides with the previous onel<I>~> S .Int in thelimit of d C = d V. But this choice will become more suitable if the coupling between thevalence neutron and the clusterized core is weak and they move almost independently
with each other. This wave function represe~ts a separated system composed of 8Be
and a nucleon in the case when d V is infinite and d C is finite. Figure 3 shows thevariational energy surfaces in these states as functions of the parameter d. We havesomewhat larger variational energy by taking the wave function 1<I>~ > S'.Int. This may
suggest that the valence nucleon is coupled relatively weakly to the 8Be core in thepositive parity state. We have equilibrium minimum in all variational surfaces atlarge d, which seems to support the experimental information, which is positive as forthe existence of the low -lying anomalous parity state.
We assumed in the preceding paragraphs that the valence neutron is coupledstrongly to the core independently of its parity. Especially, we have assumed that theclusterization parameter d v in the wave function of valence nucleon is parallel to dC,
which specifies the direction of the core. It should be noticed, however, thatexperimentally there has been found a clear rotational band of strong coupling type only
for the case of negative parity. In explaining the missing of rotational band withpositive parity we adopt a weak coupling pictureS} to the positive parity states (see Fig.
4), although we may attribute the missing to large effect of decoupling because of its K
value, K = 1/2, if we s tick to our previous picture of strong coupling. 6 }62~ - 20
::2

o

2

3

4

5

6

7

8

9

10

11

12

d

Fig. 3.

Energy surfaces as functions of the parameter d.
The size parameter b was fixed to 1.31 fm, andthe energies were calculated by use of Volkov
force no.1 with m=0.60. The upper solid curve isobtained for the wave function I <I> ~ > S.Int. by
varying the parameter d with restriction of
dC=dv =d. The dashed curve and the lower solid
curve are obtained for the same wave function
and for the wave function <I> ~ > S:Int. respectively,
but by taking the best value of the parameter d C
at each value of the parameter d V , which becomesto be about 3.0 fm in almost all cases. This value
corresponds to that value for the free SBe system.

I

We have examined the situation in which the valence nucleon feels the orientationof the core by rotating only the valence nucleon relatively to the core. The expectation
value of Hamiltonian are shown in Table 1 as a function of the rotation angle (). We seea large energy gap between the cases of {} = 0 and () = 7C/2 only in the state of negati ve
parity. The valence nucleon seems, on the other hand, to take all values of () withrelatively. small energy change in its positive parity state. This difference between
opposite parity states is caused mainly by the Pauli principle. The situation may beunderstood if we consider the case near the limit of shell model. The negative parity
single particle wave function of valence nucleon becomes a combination of shell model
configurations mainly with 3 hw or larger quanta in the case when () is 7C /2 instead of
1 hw configurations in the case when () is ze ro, because lower configurations are alreadyoccupied by particles in the core. The single particle wave function, on the other hand,is mainly 2 hw configuration independently of () in the positive parity state.
Our interest, thus, lies in the examination if we have a lower variational energy bymaking the wave function of the valence nucleon have a good angular momentum by itself
in the case of positive parity. This situation is very different from that for the groundstate with negative parity, where only its z -component is a good quantum number. The
wave function thus obtained may be called a weak coupling "intrinsic" state. A result
is given in Table 2 by ass uming the following approximate wave function;

63

N

p

Fig. 4.

Angular momentum projection scheme in the total
system. The figure indicates that in the anomalous
parity state, the valence nucleon may have a goodangular momentum by itself, which is then coupled
to that of the latter to form the fina 1 angu lar
momentum.

The quantities E/ /, EJ... and Ew are the expectation values of Hamiltonian in the states

aO. .(dt(2', O = O))Id>~ > , a+O.N. (dt(2', Oy= 1r/2))1d>~ > and 1d>~ > W.lnt.
N

respectively. This table shows that the weak coupling "intrinsic" state gives almost
the same binding energy as that of strong coupling one. This may suggest that thestrong coupling intrinsic state is not so stable in the case of anomalous parity. Thistendency of preference for a weak coupling type of angular momentum projection inanomalous parity state may occur more distinctly in the system, where there arealpha -like valence nucleons' group because of their gain in the intrinsic correlationenergy in addition to the kinematical effect mentioned above. 7)

64

Table 1.

Energy changes as functions of the parameter f) . The table showsthat the valence nucleon feels the orientation of the core strongly
only in the negative parity state.

b = 1.6

..

dC

g

0.2

dC

u

0.2

dV

3.0

4.0

A

45°

90°

0°

45°

90°

T

137.6

137.6

151.1

145.7

144.8

143.9

V

- 176.4-176.4-132.7-175.4-172.1- 168.9

E- 38.74- 38.7318.50- 29.60- 27.27- 24.93

0.01

57.24

2 .33

4.67

- 36.62- 32.92

2.75

6.45

0.2

T

115.4

115.6

127.7

V

- 159.2- 155.7-151.3E- 43.79- 40.20- 23.54

3.59

20.25

3.0

JE

3.0

p

A.

0°

JE

3.0

N

- 39.37

T

112.4

111.3

109.9

V

-153.3-148.2-142.8E- 40.96- 36.92- 32.78

4.04

8.18

4.0

LIE

0.2

0.2

T

136.3

142.1

V

. - 166.2- 161.8

E- 29.84- 19.77

0.6

.dE

10.07

- 22.34- 20.80
1.54

65

Table 2.

Comparison between intrinsic energies in the stateswith strong and weak coupling scheme of angularmomentum projection.

dC

E

E

EW

0.2

3.5

- 30.08- 30.08- 30.08

4.0

3.5- 33.83-26.34-32.839.0

3.0- 29.14-26.58- 28.02

References:
I}
2}
3}
4}
5}
6}

7}

K. Ikeda et al.: Progr. Theor. Phys. Suppl. (1972) to be published;
A. Arima et al.: Advances Nucl. Phys., ~ to be published.
F.C. Barker: Nucl. Phys., 83, 418 (1966).
A.B. Volkov: ibid., 74, 33 (1965);
A. Hasegawa and S. Nagata: Progr. Theor. Phys., 45,1786 (1971).
G. Jacob and Th. A.G. Maris: Rev. Mod. Phys., 38,121 (1966).
T. Sebe: Progr. Theor. Phys., 30,290 (1963);
D. Kurath and R.D. Lawson: Nucl. Phys., 23, 5 (1961).
F.S. Stephens, R.M. Diamond, J.R. Leigh, T. Kammuri, and K. Nakai: Phys. Rev.
Lett. 29, 438 (1972)
N. Takigawa and A. Arima: Nucl. Phys., 168,593 (1971);
Y. Suzuki, H. Horiuchi and K. Ikeda: Progr. Theor. Phys., 47,1517 (1972);
F. Nemoto and K. Bando: ibid., p. 1210.

66

5. NUCLEAR PHYSICS
Nuc lear Spectroscopy
5-1.

The Gam rna-Decay of 146, 150, 152 Sm following the(a, 2n)Reaction

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

The energies of the lowest excited states of even -even nuclei with angularmomentum of 2+, 4+,6+ and 8+ etc. change suddenly from 146Sm to 152S m , because
these nuclei lie across the spherical to permanent deformed regions. The excitedenergies of these so -called quasi -rotational bands up to the 8+ or 10+ states were
established and reported previously.1),2) Our concern is related to the relativetransition intensities in these ground state bands as the last process of de -excitation of
the compo.und nuclei. These nuclei formed by bombarding with alpha -particles haverather large angular momentum which should be dissipated with evaporation of particles
or emitting r -rays until they decay to the ground state. This large loss of angularmomentum of nuclei could not been explained by the conventional statistical theory.
The enriched targets 144,148,150Nd were bombarded with alpha-particles of 18
MeV to 45 MeV in 2.5 MeV steps and r -rays were observed with a Ge(Li) detector.
Figure 1 shows energy levels of ground state bands in 146,150,152S m which are in good
agreement with the results in Ref. 2). The transitions in the ground state band wereconsidered to be pure E2 and the intensities of electrons in the transitions werees ti mated from the table of the conversion coefficients by Hager and Seltzer. The
relative transition intensities (Ir + Ie) of 4+ ~ 2+, 6+ ~ 4+ etc. to 2+ ~ 0+ transition inthe (a ,2n) reaction are plotted in Fig. 2 (a), (b), and (c) as a function of bombarding

( 8+)

2738
(10+)

2435

926.1
597.6

( 6t )

181 2( 8t )

(10+)

430.3
4+

1837
1609

558.1
13814
6t

484.1

1279
(8+)

634.0

1125

505.5
418.4

2+

747.4

4+

773

6+

439.4
747.4

2+

707
340.4

333 .9

4+

366.5
244.7

333.9
0+

0
146 S m0+0150S m

2+
0+

121.8
152S mFig. l. Energy levels of ground state bands in
146, 150,152S m nuclei.

121.8
0

67

1. 5r-- - - - - - - - - .- - -- - - - r- - - --

-,

+

o

)

N

1.0

N

+

-"

~ 0.5

~~
0-----~30~----~
40~----~50
Ea (MeV )1.5,----- - -- -- -- - -- - - ,1. 5 ,--- --

-

-

-

- - - --

En:

(MeV)

------.

1.0

o

}
N

-

~ 0.5
-,

0~-~20~-~---3~0~-~--~40

Ea

(MeV)

20

30

40

Fig. 2 . (a) Transition intensity ratios of 0+2) - J to 2+ - 0+ in 146Sm wereplotted as a function of bombardi ng energy of alpha -particles. (b) The
same as in Fig. 2(a) for 150Sm , (c) The same as in Fig. 2(a) for 152S m .

energy.
From Fig . 2 it is seen that the change of the relative intensi ties in terms of
the bombarding energies in 150S m and 152S m is nearly the same in spite of thedifference of the excited energies of the ground state bands. However, the change isslow in 146S m as shown in Fig. 2 (a).
Rough estimate of the angular momentum
introduced in compound nuclei by classical model gi ves a value of about 8 (in units ofh) for E a = 25 MeV and 11 for E a == 30 MeV. And the nucleus does not essentiallychange the angular momentum distribution by neutron evaporation. The difference inrelative intensities of r -rays between 146S m and 150s m or 152S m can be attributed tothe difference of angular momenta introduced in the compound nuclei. When thesamarium nuclei get to have rotational structure, the curve of the excitation energies of

68

8

>-

e-

O.>

c

0.>

c
-~

:2 4
u
><

w

2

O~~--~--~--~--~
10~~--~--~--~~
20-

I(in un it of 1'1 )Fig. 3. Schematical representation of the lastprocess of de -excitation of compound
nuclei.

the ground state band as a function of angular momentum rises more slowly comparedwith the 146Sm , showing that there are more side feeding r -rays in lS2S m when thebombarding energy of alpha -particles is low. These circumstances are shown
schematically in Fig. 3.
In case of 152S m , the K-selection rule may playa role, but
a more precise examination is required to confirm this effect.
The intensity ratios between the ground state band transition and the side feedingr -rays depend on three processes: 1) energy and especially angular momentum
distributions of compound states, 2) evaporation of neutrons, and 3) cascade r -rays
as the last step to reach the ground state band. The first two problems were recently
treated statistically by Jagare 3 ) and Ejiri ,4) and there are many experimental
studies S )---- 7) in the rotational region by exciting the nucleus with alpha -particles.
In comparison with the statistical model, the population of the high spin states in the
ground state band is small and deviates from the theoretical estimate. Some stress
was pronounced on the r -ray decay near the yrast-level by Freguson et al. 8 ) Further
experimental analysis and theoretical studies are in progress.

69

References
I}
2}
3)
4)
5}
6}
7}
8)

H. Morinaga: Nuc!. Phys., 75, 385 (1966).
1. Adam, L-E Froberg, J. Kownacki, H. Ryde, and Z. Sujkowski: Annual Rep. of
Res . lnst. Phys., Sweden, P.36 (1970).
S. Jagare: Nucl. Phys., A95, 481 (1967).
H. Ejiri: Bull. Am. Soc., 13,700 (1968).
C. D. Kavaloski, W. J. Kossler, and C. F. Williamson: Nuc!. Phys., A124, 401(1969).
A. S. M. De Jesus, S. J. Mills, and W. L. Rautenbach: ibid., A172, 323 (1971).
A. Johnson, H. Ryde, and J. Sztarkier: Phys. Letters, 34B, 605 (1971).
S. M. Ferguson, H. Ejiri, and 1. Halpern: Nucl. Phys., A188, 1 (1972).

70

5-2.

Decay of

87Zr and85 Zr (II)T. Katou, Y. Awaya, Y. Tendow,
A. Hashizume, and T. Hamada

The results of gamma -ray studies on the decay of 87Z r and 85Z r were reported
previously,l) in which the r - r cOincidence measurements of 87Zr by using a Ge(Li)detector and a NaI(Tl) detector were des cribed along with the energies and relative
intensities of the gamma -rays. The information obtained by previous r - r coincidence
works, however, was not so clear -cut because there were many gamma -rays which
could not be resolved by the NaI(Tl) detector.
Table 1.

Result of the

772

794(+797)

r - r coincidence for 87Z r .

Gate

Er

511

1024

1159

1203

611

1210

1227

+

633

+

772
794

+

797
973

+

1024

+

(+)

1048

+
+

1159

+

1203

+

1210
1227

+

(+)

1388
1410

+
+

+

1657
1808

+
+

+

(+) mean s that coincidence of thes e gamma rays is not very certain.

71

In this paper, the r - r coincidence measurements were made for 87Zr and 85Z r
by using a 23 cm 3 Ge(Li) detector and a 29 cm 3 Ge(Li) detector. In the study ofcoincidence between annihilation gamma -rays and others, the triple coincidence
technique using the 23 cm 3 Ge(Li) detector and two 7.6 cm in height and 7.6 cm indiameter NaI(TI) detectors were employed to reduce accidental events. The block
diagrams of the coincidence circuits are shown in Fig. 1.
The results ofmeasurements are shown in Tables 1 and 2. Because of poor statistics, ambiguities
are left in some cases and only definite results are given in these tables. The present
results on 87Z r show that there are few misassigned transitions in the previously
proposed decay scheme and a revised one is under construction.

ND MULTI

y

x
CO IN

COIN
PA

: Pre - amp.

xy

AFA : Active filter amp.

ND MULTI

SAfA : Selectable active filter amp.
CFTD ; Const. flactian timing
discriminator
TSCA : Timing single channel
ana lyzer
DA : Delay amp .
LG: Linear gate

(a)

(b)

Fig. 1. Block diagrams of r - r coincidence sys terns, a) is used forthe coincidence measurement using a 23 cm 3 Ge(Li)detector and a 29 cm 3 Ge(Li) detector, and b) is used forthe triple coincidence measurement.

72

Table 2.
Gate

ErRes ul t of the r - r coi ncidence for 85Z r .

265.4

415.1

453.1

511

1191.1

+

415.1

+

1198.5453.1+1410.5621.5

1729.5635.4

1767.4

781.3
799.2

+

415.1

453.1

511

+

+
+
(+)

+

1875.1+

1936.8910.4

1954.1964.7

2143.01159.9265.4

1171.1

265.4
356.8

Gate

Er

+

+
(+)

+

+

2387.7

Reference
1)

Y. Awaya, T. Katou, Y. Tendow, A. Hashizume, and T. Hamada: IPCR Cyclotron
Progr. Rep., ~, 57 (1971).

73

5-3.

Magnetic Moments of High-Spin Isomeric States in Po Isotopes

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

The g-factors of the 8+ state of 204po and of the 13- state 1 ) of 210po have been
determined, and the g - factors of the 8+ states of 2IO,208,206po and of the 17/2- state of
209po have been remeasured. 2 )",-,4) These isomeric states were populated via(particle, xn) reactions with the beams from the cyclotron. Targets and reactions usedhere are listed in Table 1. Gamma -rays following the (particle, xn) reactions weredetected by two NaI(T 1) counters placed at angles 60 0 and 13S o except for the case of
204po in which a Ge(Li) detector was used. The stroboscopic resonance methodS) wasused for the 8+ states of 210,208,206,204po and the 17/2-state of 209po, and the timedifferential spin -rotation method for the 13- state of 2IOpo. In the stroboscopic
resonance method a magnetic field applied perpendicularly to the beam -detector plane
was automatically swept near the resonance field calculated from the expected g-factorof each state and the interval between the natural cyclotron beam bursts. In case of the

21OpO

St

204Pb

+ 25 MeVo(

0.95

1.00

0.90

O.SO

f

0.90

0.S5

0.70

206PO--"-'- 206Pb+30M,V 3H,

1. 30

1.00

090
1. 20

O.SO

12

14

13

15 kOe

140

1.20

1.10
I

11

! ! !

12

13

14

15

--.L......--...

16

17
kOe

Fig.!. Stroboscopic resonances for the 8+ states of
210,208,206,204po and the 17/2-states of
209po.

J

74

Table 1.

Reactions to populate the states whose g factors
were meas ured .

J7r

Particle

Reaction

Energy (MeV)

210po

8+

a

208Pb(a ,2n)

25

209po

17/2-

a

207Pb(a,2n)

28

208po

8+

3 He

208Pb(3 He ,3n)

28

206po

8+

3He

206Pb(3 He ,3n)

30

204Po

8+

3He

204Pb(3He,3n)

30

210po

8+

a

208Pb(a,2n)

33

2000
Z08Pb(cx,2n ) 210po

13-State(t v2=93ns)

1000
'\-.>

-<I

<D

...........

Z

I

0

--~~--~--~-----D~Burst
Burst

z
-1000

CVL= 56.2 't1.3

MHz

Ecx= 33 MeV

Ho= 21.03 t 0 .10kOe

-2000

o

117.1

Time

(ns)

Fig. 2. Time -differential pattern for the 13 - state of
210po.

time-differential spin-rotation method used for the 13- state of 210po, a magnetic fieldof 21.03 ± 0 .10 kOe was applied up and down perpendicularly to the beam -detector plane,
and the time calibration was performed by observing two prompt peaks in the time
spectrum . Figures 1 and 2 show the experimental results. The g-factors obtained
are listed in Table 2 together with the calculated g-factors deduced from the known
g-factors of single particle states by use of the additivity relation.
The experimental g-factors agree with the calculated values. This fact suggeststhat the main configurations of all the 8+ states are (7rh 9 72)8+. 6 ), 7) It is somewhat
remarkable that the 8+ sta tes of 206 ,204Po, which are far from the single closed shell,
have rather pure configurations. Furthermore, the additivity relation of the g - factor
hol~s well even for th~ core excited state such as the 13- stat~ of 210Po, sup~orting theaSSIgnment of Blomqvlst et al. l ) that the 13- state of 210po arIses from (nh 9 / 2 )8+
coupled to the 5- s ta te of the 208Pb core. The reas on why all of thes estates have such
pure configurations may be ascribed to the fact that these states have high spins.

75

Table 2.

The experimental g-factors together with the expected
main configurations of the states and the calculated g-factors.

J7r

T 1/2
( ns )

210po

S+

110

209 po

17/2-

20S poConfiguration

gexp

gcal~

2
7rh9/20.901 ± 0.013

0.910

100

2
-1
7rh9/2 vp 1/2

o.S97 ± 0.015

0.926

S+

3S0

2
-2
+
7rh9/2 ( vP l/2)00.911 ±0.010

0.910

206 po

S+

212

2
-2
-2
+
7rh9/2 ( VP l/2 vf5/2)00.905 ±O.OlS

0.910

204 po

S+

140

2
-2
-2
+
7rh9/2 ( vP 1/2 vf 5 / 2 )00.905 ± 0.040

0.910

210po

13-

93

(7rh~ / 2) 8+(2) 5- (20 8Pb )0.546 ±0.012

0.563* Deduced from the known g factors by use of the additivity relation of the g factor.
The decre~Int of g(210po ,8~ from g(209Bi ,9/2) may be due to the blocking effecton the (7rh9/2hll/2) 1+ type core polarization. S) The increment of g(208Po,S+) fromg(210Po~+) maybe due to the ( vP 3/1 P l/2) 1+ type core polarization. 8) A mixture of the(8+ x vP372)17/2- configuration decreases the value of g(209po,17/2-), and so this small
mixture is expected from the small difference between gexp and gcal of the 17/2 - stateof 210po.

References
1)
2)
3)
4)
5)

6)
7)
S)

J. Blomqvist, D. Fant, K. Wikstrom, and 1. Bergstrom: Physica Scripta, 1,9(1971).
T. Yamazaki, T. Nomura, T. Katou, T. Inamura, A. Hashizume, and T. Tendow:
Phys. Rev. Letters, 24, 317 (1970).
T. Yamazaki, T. Nomura, S. Nagamiya, and T. Katou: ibid., 25,547 (1970).
S. Nagamiya, T. Nomura, and T. Yamazaki: Nucl. Phys., A159, 653 (1970).
J. Christiansen, H.E. Mahnke, E. Recknagel, D. Riegel, G. Weyer, and
W. Witthuhn: Phys. Rev. Letters, 21, 554 (1968); S. Nagamiya and K. Sugimoto:
Osaka University Report, OULNS, 69 -3 (1969).
T. Yamazaki: Phys. Rev., C 1, 290 (1970).
S. Nagamiya and T. Inamura: Nucl. Phys., A182, 84 (1972).
A. Arima and H . Horie: Progr. Theor. Phys., 12,623 (1954).

76

5-4.

A

Method of Measuring A Ipha-DecaysIn

the Nanosecond Range

T. Nomura, K. Hiruta, T. Inamura, and M. Odera

Many neutron -deficient elements beyond lead are known to be high -energy a emi tters wi th short half -li ves . In particular the nuclides with 128 neutrons are
expected to have the largest a -decay energies due to the extra stability of the N=126
neutron shell, and lifetimes of these nuclei will fall in the submicrosecond region. It isalmost impossible to measure such short lifetimes by the usual "off-beam" preparationof a -activities. Even the rapid helium -jet collection system needs much longer
transportation time (us ually longer than 1 ms) and thus, measurements of lifetimes
shorter than microseconds have been limited to cases where activities of interest areprovided from the decay of parent nuclei having sufficiently long half-lives. We havetherefore developed a simple pulsed -beam method of observing a -decays with lifetimes
ranging from microseconds to a few nanoseconds.
The principle of the present method is to produce a -emitters by nuclear
reactions, to s top them within a target used and to observe a -decays between natural
beam bunches of the cyclotron with the help of the fast electronics. This method isessentially the same as the one employed by Yamazaki and Ewan 1 ) in the study of
gamma decays from nanosecond isomers. The beam spread of the cyclotron is around2ns and its repetition period ranges from 80 to 150 ns depending on accelerated
particles and their energies. Alpha-particles were detected with a Si -detector of
surface barrier type placed at 135 degrees to avoid strong Coulomb scattering ofincident particles. The depletion layer of the detector was about 200/.L m and themeasurable maximum energies were around 0.2 MeV, 5 MeV and 20 MeV for electrons,
protons and a -particles, respectively. This property of the thin Si -detector is very
convenient since we are interested in short-lived a -decays having high decay-energies,

Fig.!. The schematic diagram of thepres ent e lec troni cs .

77say, from 5 MeV to 15 MeV. Although no special particle -identification technique wasused, the above property of the detector and the electronical system of taking delayedparticles turned out to be enough to discriminate delayed a -particles from prompt
emission of other charged particles following reactions and also from possible delayedemission of protons and fission fragments.
The electronics used is shown in Fig. 1.
In order to check the timing propertyof this system, the prompt emission of charged particles such as protons and alphas
having energies between 5 MeV and 15 MeV in the 32S + 12C (81 MeV) reaction was
detected by the same system. The time resolution obtained was around 2 ns, being
almost the same as the spread of the beam burst.
Figure 2 shows a typical time distribution of charged -particle emission following
bombardment of a 208Pb target of about 1 mg/cm 2 thickness with 91 MeV 14N-beam.
In this case a time resolution of the prompt curve was 5.6 ns, being considerably
broader than the one mentioned above. This can be explained by the fact that there arethree gross groups in velocity distributions of charged particles which cause the prompt
part of the time spectrum; light particles such as protons and alphas, s catte red incident
heavy ions, and fission fragments.
Typical energy spectra in various sections of the delay time taken by using a twodimensional PHA are presented in Fig. 3.
They were observed when a 1.5 mg/cm 2
207Pb target was bombarded with 81 MeV 14N -ions. The spectrum shown at the top of
the left side of this figure includes the prompt component and therefore has appreciablebackgrounds with continuous energy distributions, while almost no backgrounds exist in
the delayed spectra in the energy range from 5 MeV to 15 MeV. Two prominent peaks
at 9.65 MeV and 6.77 MeV were due to decays of a previously unknown element 217Ac
1 0 4~------~--------~1---------~
1------~--------~------'

5 c-

208Pb

+ 14N (91 MeV)
f------- - - 132 ns

TIME SPECTRUM

1'l.

it

.

-_ it _

FWHM
5.6 ns

i\

f \

i l
. \
j

..

"' .
..,:..
••.' . ':'.:' ......... -',.

.. tI'

','"

"

•

•

i
.\

'\

. .'. ::

Fig. 2. A typical time distribution of charged
particles taken by the electronics system
shown in Fig. 1. Every second pulse fromthe cyclotron oscillator generates the stop
signal of the time -to -ampli tude converter,and therefore two prompt peaks appear in
the time spectrum.

78

I

4000k2000
o <:t

LO

ci

1500

1000

500

o
1500

0 0
0°

1000

t;::;; 75 ns

1000

500

500

0

o

1500

1500

t :::: 19 ns

a.>

c
c
0

1000

1000

-- 500500~u-.....
(/)

c

:::J

0

U
.o'I!

f~:--"'''''''~'

150t

o
1500

t :::: 33 ns

X20

X20

1000

1000

500

500

.....,-"-.-.-~~......

0

0
1500

1500
t:::: 47 ns

1000

1000

500

500
~

.,..

..

t--~~
I

I

I

I

~

~--~~~~
0----~--~5~0~---L---l0~0~--~---'~50
50
0~--~----~----~---"10~0

Cha nne I

numberFig. 3. A part of two-dimensional spectra - 256 channels (energy)
times 16 channels (time) - resulting from bombardment of a
207Pb target with 81 MeV 14N-ions.

0

79

produced in the 207Pb (14N ,4n) reaction and its daughter nucleus 213Fr, respectively.2)
The 9.65 MeV peak was found to decay with a half-life of 0.10 ±0.01 J1 s, while the otherpeaks having energies lower than 9 MeV turned out to be constant in this time range.
Two small peaks at 10.54 MeV and 11.13 MeV were found to have similar excitation
functions to that of the 9.65 MeV peak and therefore assigned to the decay fromisomeric states of 217Ac. Their half-lives are 400±100 ns (10.54 MeV) and 8±2 ns(11.13 MeV).

References
1)
2)

T. Yamazaki and G.T. Ewan: Phys. Letters, 24B, 278 (1967).
T. Nomura, K . Hiruta, T. Inamura, and M. Odera: ibid., 40B, 543 (1972).

80

5-5.

A Ipha- and Gamma-Spectroscopy of N=128 Isotones

216Ra, 217 Ac, and 218Th
T. Nomura, K. Hiruta, T. Inamura,
M. Odera, and O. Hashimoto

Alpha-decays from N=128 isotones, 216Ra, 217 Ac, and 218Th, have been studied
wi th the help of the fas t detection technique developed in our laboratory)Two
previously unknown nuclei 217Ac and 218Th were produced in the 207Pb(14N,4n) and209Bi( 14N ,5n) reactions , respectively. Alpha -particles were detected with a Si surfacebarrier detector and their time distributions were taken between natural beam bunchesof the cyclotron, being analyzed with a two -di mensional pulse -height -analyze r in theform of 256 (energy) times 16 (time) channels. Typical delayed a -spectra obtained areshown in Figs . 1 and 2.
The assignment of peaks was made from their excitation
functions, energies, half-lives and decay-chain relations. The half-life of 216Ra has
been measured in the same way by using the 208Pb (12C ,4n) reaction. The decay -curvesof 216Ra, 217 Ac, and 218Th are shown in Fig. 3.
Several long-range alphas have been
also observed and assigned to transitions from short-lived isomeric states of 216Ra
and 217 Ac. The results are summarized in Table 1.
Gamma -transitions of these nuclei were also meas ured in the same system exceptthat the Si -detector was replaced with a Ge(Li) counter. Construction of decay
schemes from the knowledge of delayed gamma - and alpha -transitions is now inprogress.
I

207 Pb

4000+ 14N (81 MeV)t > 20ns

L~

3000

. '

N

80
<l>
C
C

I

a

.<=

U

2000

k

---

<I>
-+-'

C
:::J

a

U

. \ ... . /

N

I
i

(!)

!\

/.

.\
i
J i.
J

i

................... _.....

',

20
. .

o

~~
. :. ....

\.,.

20L:-:0------'-----=!250c............ .•. .

40... :/ \

u..
<t

1000

60

./.1\\ ... .ij"':'

i\ ...,............................. ,.........

\i\ ......l

j\

/' "

I'

I'

i

\.~.!
·.•., ..................................................1...... .

0L------5~0---------~
1 0~0--------~1~50~--------2~0~0~-=====~25~0~~

C ha nnel

nu mberFig. 1. A delayed alpha-spectrum following the 207Pb + 14N reaction.
Energies are given in MeV.

81

150

+ 91 MeV 14N

209Si

t > 15 ns

t-N

<.D

o

~
co

g;

100

N

ot-a:i]u......
.....
'"co

::>

0

U

50

... ...... .

..

.. j

:-.-.
..

:-...................-:--.: :...........

o100
Ch anne I

numberFig. 2. A delayed alpha -s pectrum following the 209Bi + 14N
reaction. Energies are given in MeV.
Table 1.

217Ac

218Th

Experimentally observed alpha-decays from 216Ra, 217Ac, and 218Th.

(MeV)

tl/2
(ns)

Q
sys
(MeV)

Comments

9.304 ±0.02

90480

216 ± 20

90480

gnd

9.502 ± 0.02

9.681

8 ±1

(9.666)(9.848)

10.111 ±0.02

10.3028 ±1100424 ± 0.02

10.6218 ±110.751 ± 0.02

10.9548 ±110.952 ± 0.02

11.1598 ±111.262 ± 0.02

1104 75

8 ±19.66 ±0.02

9.84

100 ± 10

9.800

gnd

10.54 ±0.02

10.74

400 ± 100

11.13

±0.02

11.34

8 ±4

9.67 ±0.02

9.85

87 ± 7

9.900

gnd

Ea

Qa

(MeV)

Given errors for the a -decay energies are absolute. For long-range alphas
errors relative. to the ground -state decay are usually 0.005 MeV.

82

216Ro

5 f-

2 f-

!

-,-

~__+_r.----r

!-!

10

3

~

t V2 =0.18::!: 0.03)Lsec

~

!

1

0

50

100

217Ac
5

f-~

~

!

~
c
a

t ~o± OOI~.-------r

L:.

U........

2I -I,..____1,..----11
1.-------

100

50

0

/

1/1

21Brh
5 f-

/

I

./

/1

I

/~ t'i2~O.087±0007

2 l-

I

100

I

50
Tim e delay

}iSOC

I

o
(n sec)Fig.3. Decay curves of the ground -statealpha transitions of 216Ra, 217Ac,
and 218Th.
Table 2 compares the experimental reduced a -widths of N=128 isotones withthose calculated on the basis of the shell model. The experimental reduced width isdeduced fromr2 _ J2.L.
a 2

1

P

where A is the a -decay constant and P the barrier penetrability calculated for S -wa ve
a -particles using a pure Coulomb potential at a radius of R = 1.57 A 1/3 fm. Because
absolute values of r2 are very sensitive to the choice of R and moreover the nuclear
potential was neglect~d in defining the barrier, only relative values ofshould beconsidered to be significant. The shell model predicts, as the simplest configuration,( 7[ h 9/2) 9/2 (II g29 2 ) oj
for the odd parents and[ (7[ h n9/ 2)0 (vg 29 / 2 )o]O+for theeven -even parents. Y Assuming the above configuration for parent - and n; h~/i (closed
shell for neutrons) for daughter-nuclei we have calculated theoretical values of r~
after Mang, 6) which are given in the fifth column of Table 2. Agreement withexperiment is generally quite good except in the case of 218Th.

r&

Y2-

83

Table 2.

ParentnucleusEa(MeV)

Experimental and theoretical a -reduced widths ofthe ground -state a -decay of N=128 isotones.

tl/2
(,us)

2
r a(exp)2
ra(cal)

(keV)

(keV)

Ref. forexperiments

212po

8.785

0.304

1.49

1.49 a )

2

213At

9.080

0.11 ±0.02

1.74

1.19

3

214Rn

9.035

0.27±0.02

1 :79

2.38

4

215Fr

9.365

1.79

5

216Ra

9.304

o.18±0.03

2.32

2.68

Present

217 Ac9.66 ±0.02

0.10±0.01

1.60

1.79

Present

218Th

9.67 ±0.02

0.087 ±0.01

3.43

2.38

Present< 0.5

The reduced width of 212po is taken as a standard and set equal to theexperimental reduced width.

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

T. Nomura, K. Hiruta, T. Inamura, and M. Odera: IPCR Cyclotron Progr. Rep.,~, 76 (1972); Nucl. Instr. Methods, in press.
Table of Isotopes, 6th edi tion (ed. by C.M. Lederer, J.M. Hollander, and I.
Perlman), John Wiley & Sons, N. y, (1966),
J, Borggreen, K. Valli, and E .K. Hyde: Lawrence Radiation Laboratory Report,
UCRL-19539 (1970).
K. Valli, E.K. Hyde, and J. Borggreen: Phys. Rev., Cl, 2115 (1970).
R.D. Griffioen and R.D. Macfarlane: Lawrence Radiation Laboratory Report,
UCRL -10023 (1961).
H.J. Mang: Phys. Rev., 119, 1069 (1960).

84

5-6. 9 Factor Measurement of the 8+ State

In

86S r

Produced in Kr Gas

O. Hashimoto, E. Matthias, K. Nakai, S. Nagamiya,
E. Recknagel, T. Yamazaki, and Y. Yamazaki

Ishihara et al. 1) reported on the 8+ isomeric state in 86S r and determined thehalf life of this state to be 0.46 ± 0.03 tt sec (see Fig. 1). This state was explained asa neutron-two-hole state ( Vg 9/2- 2 ) assuming 88sr to be the core. Previously, the gfactor of this state was measured by Hashimoto et a1. 2 ) to be g =-0.241 ± 0.015 by thespi n rotation method.
Our interest in the present experiment was the following two points;
1) To determine the g factor of this state more accurately to examine theadditivity relation of the magnetic moment between the 9/2+ state in 87S r and the 8+
state in 86S r .
2) To ascertain whether the nuclear alignment produced by the 84Kr (a,2n) 86S r
reaction is preserved in Kr gas and to investigate the relaxation mechanism in thettsec
region.
Natural Kr gas (84Kr; 56.9 %) was irradiated by 22 -MeV a particles from thecyclotron to populate the 8+ state. The press ure of Kr gas was 3 atm. The diameterof the target gas chamber was 8 mm and the length was 10 mm, so that recoiling ionswere stopped in Kr gas. A Harvar foil of 3 tt m thickness was used as the window.
To meas ure the g factor of the 8+ state the stroboscopic resonance method wasused. The r -rays were observed with two NaI(T 1) counters placed at 45 ,and 135
degrees to the beam axis. The composite peak of 1154 keV and 1078 keV r -rays wasused for analysis. The stroboscopic resonance at n=1 was observed as shown in
Fig. 2, from which we obtained
g (8+; 86S r ) = -0.242 ± 0.004

8+6+

0.46 ~sec
99

2958
2859

627
2232

4+

1156

2+

1078

Fig. 1. Relevant energy
levels of 86S r
as proposed by
Ishihara et al.

85

84 Kr ( ex , 2 n ) 86Sr

1.10

State

StroboscopIC
resonance

tY2 = 0.46 =to.03,u sec( n= 1 )

8+

1.09
1.08

fr = 6.996 MHz.3o 1.07
I....

~ 1.06=>oo
f 1.05

1.04
1.03

13

14

15

16
-

Mag net ic f ield

(K G)

Fig. 2. The n=I stroboscopic resonance. Solid curve
gives the best fit assuming a Lorentzian line
shape.

.
Table 1. Experimental
and calculated g factors for 8 7S r an d 86S r.
Main
configuration

gSchmidtaagA.H. )

b)
gcal

gexp

87S r

v g9/2-1-0.426+0.237- 0.189- 0.2429 c )86S rvg9/2 - 2

-0.426-t{) .210- 0.216- 0.242 ±0.004d )

a)
b)
c)
d)

a gA.H. is calculated by the theory of Arima and Horie.
gcal = gSchmidt + agA.H.
From Ref. 3).
Value obtained in this experiment.

The conf!guration of the ground state in 8 7S r is considered to be the one -holestate of the g9/2 neutron. The g factor of this state is known to be g = - 0 .2429 by the
NMR experiment 3 ) which is very close to the present result. This shows that theadditivity of the magnetic moment between the 9/2+ state in 87S r and the 8+ state in
86S r holds well, though these g factors deviate from the Schmidt estimate of -0.425.
This deviation ag = gexp -gSchmidt = 0.18 is nearly accounted for by the theory of Arimaand Horie (agIst = 0.23) (see Table 1).
The width of the stroboscopic resonance observed was '"'-' 7 %which is notconsiderably broader than the natural width of the resonance (6.2 %). The relaxation
time was estimated to be of the same order as or longer than the mean lifetime of the8+ state in 86S r , namely T relax;;;:: 0.5 IJ,sec.

86

The spin relaxation process in Kr gas could be di vided into two stages. In thefirst stage, recoiling Sr ions travel through the Kr gas and were slowed down very
quickly to thermal energy by atomic collisions with Kr atoms. The second stage
concerns with a s tate when Sr ions have been thermalized in Kr gas. Because of thehigh pressure of the Kr gas and the high velocity of the recoiling atom, the correlation
time is so short in the first stage that the nuclear alignment is expected to be preserved
well by frequent atomic collisions. In the second stage the correlation time is too longto randomize hyperfi ne fields caused by unpaired s electrons if they exist. However,the present result showed that the nuclear alignment was preserved longer than 0.5
tLsec. This indicates that the hyperfine interactions must be very weak or do not exist.
This situation can be realized if the Sr atoms were in the neutral atomic state, ISO' andthe mean time for the neutral Sr atoms picking up an electron in Kr gas was longer
than the nuclear lifetime of "'-'0.5 tL sec. It is also noticed that the doubly charged Sr ion
has an atomic closed -shell configuration, namely Kr, which produces no hyperfine
field. As for the quantitative argument the study is still in progres s.

References
1)

2)
3}
4}

M. Ishihara, H. Kawakami, N. Yoshikawa, M. Sakai, and K. Ishii: Phys. Letters,
35B, 398 (1971).
O. Hashimoto, T . Nomura, T. Yamazaki, K. Miyano, and M. Ishihara: Contr. Intern.
Conf. Nucl. Moments Nucl. Struct., 3 -16 (1972).
Table of Isotopes, 6th edition (ed. by C.M. Lederer, J.M. Hollander, and I.
Perlman), John Wiley & Sons, N.Y. (1966)
A. Arima and H. Horie: Progr. Theor. Phys., 12,623 (1954).

87

6. NUCLEAR INSTRUMENTATION

6-1.

A

Dual Ge (li)Gamma-Ray Spectrometer for Nuclear Study

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

A standard gamma -ray spectrometer using a semiconductor detector has been
employed for meas urements of gamma -rays accompanying nuclear reactions as well as
those from radioactive nuclides produced by the cyclotron)' 2)
Recently, a new Ge(Li) detector was added to the detector assembly of thestandard spectrometer, and a gamma -ray spectrometer consisting of a pair of Ge(Li)detectors mounted ins ide a split annulus of NaI(T 1) scintillator was cons tructed . The
dual Ge(Li) gamma -ray spectrometer system is expected not only to use for studying
characteristics of coincidence of gamma -rays but also to find applications in theanalysis of radionuclides that emit coincident gamma -rays or multiple cOincident
gamma -rays.
The new Ge(Li) detector is a closed -end coaxial type with an active volume of 29
cm 3 (OR TEC, System Model No. 8301-0325). The detector cryostat has an aluminumend cap of 8 inch in length and 2 -----1/4 inch in diameter, which is able to insert into theannulus type NaI(T 1) scintillator of the standard gamma -ray spectrometer. Its peakefficiency is 1.5 % for a 137 Cs 662 keY gamma -ray_source placed on the front surfaceof end cap, and the resolution is 2.3 keY FWHM for 60Co 1332 keY gamma-ray.
The detector is mainly used for a coincidence gate and its signal is sent to an
ADC connected with a digital gate unit. The function of this unit is to convert a selected
address to a fixed channel. This pulse height selection system, combined with a twoparameter multichannel system, will digitize the pulse height to 4095 channel full scalewith provisions of four selective lower- and upper - level pair digital gates.
In Fig . 1 is shown a block diagram of the arrangement used for a COincidence
dual Ge(Li) two -parameter spectrometer.

Y(4ch)
NO 2201
two-paramete
multichannel
analyzer
sys temX(1024ch)

Fig.!. Block diagram of dual Ge(Li) coincidence r -rayspectrometer.

88

References
1)
2)

M. Okano, ·A. Hashizume, Y . Awaya, Y. Tendow, K Kato, and T. Hamada: IPCR
Cyclotron Progr. Rep., ~, 110 (1968).
M. Okano, y. Tendow, T. Katou, K. Izumo, and T. Hamada: ibid.,~, 75 (1971).

89

6-2 Partie Ie Identification Study for Z
Using a= 3 to Z = 7 Partie lesPower-Law Type Partie Ie Identifier

S. Nakajima, 1. Kohno, 1. Yamane, M. Yoshie,
M. Odera, and H. Kamitsubo

A combination of a counter telescope consisting of J E and E detectors and apower-law type particle identifier was used to identify heavy particles produced innuclear reactions induced by heavy ions. Satisfactory results were obtained byadjustment of the circuit parameters.
This type of particle identifier employs an empirical range -energy relation 1)
R =aE n ,(1)
where R=particle range in the absorber,
a=constant depending on the type of particle,
n=constant (about 1.73 for Z=l and 2 particles),E=incident particle energy.
Figure 1 shows the range -energy relations 2) for several particles. Equation 1 issatisfied well by the light particles such as p, d, a etc., but apparently heavier particles
do not follow such a simple law. However, if the exponent of the power law is treatedas an ,adjustable parameter, Eqn . 1 can be applicable to heavier particles at highenergies or at a limited range of energy.
Identification study of heavy particles with this method was undertaken bybombarding a 12C target and a 46Ti target with a 90 MeV 14N beam. The block

500

100
~
~

- 50
. >0'
~

Q)

c
W

10
5

Range in Al( mg / cm 2 )Fig. 1. Range -energy relationship.

90

Fig. 2. Block diagram of electronics.

1000

14N _

Elob

12C

= 90 MeVp, 1. O.

Spectrum

750

:::>

o

U

500

250

200

400
Channe lnumbers

Fig. 3. A particle identifier spectrum resulting from thehombardment of 12C with 90 MeV 14N beam.

91

diagram of the electronic circuit used is shown in Fig. 2.
A totally depleted silicondetector was used as a L1 E detector, and a silicon detector of 200 /l thick was used as
an E detector. The thickness of the LJ E counter (60 /l) was chosen in such a way thatheavy particles of interest lost about a half of their initial energies in it. By use ofthis L1 E counter, the energies of the heavy particles could be detected in the region
above 50 MeV, where the range-energy relations of heavy particles could beapproximated by Eqn. 1 with a constant value for n. The exponent of the power law wasvaried between 1.75 and 1.45. When the value was set at about 1.73 or 1.45, theidentifier spectrum did not represent a clear separation because of a tail caused by adeviation of Eqn. 1 from the real range-energy curve. Setting the value at about 1.6,
we obtained satisfactory results as shown in Fig. 3 and Fig. 4.
A greater energy range can be covered by choOSing properly the thickness of the
L1 E counter and the value of exponent accordi ng to the energies of particles desired.

200

14N _46

Ti
Elab = 90 MeV

P. 1. O.

S pect rum

150 1

Xzoo

'"

~100
o

u

o

700
Chann eln urn be rs

Fig. 4. A particle spectrum resulting from the bombardment of
46Ti with 90 MeV 14N.

References
1)
2)

F. S. Goulding, D.A. Landis, J. Cerny, and R.H. Pehl: Nucl. Instr. Methods, 31,
1 (1964).
L.C. Northcliffe and R.F. Schilling: Nucl. Data Tables, A7, 233 (1970).

92

6-3.

On a Model of Wire Spark Chamber with Ferrite Memory
C ores for Broad Range Magnetic Spectrometer

J. Fujita and S. Takeda
The outline of a model of the wire spark chamber with ferrite memory cores was
described in a previous report)
We give here methods to solve several problems andresults of test using ft -rays.
An abbreviated block diagram is shown in Fig. 1.
A new gate was introduced
into the reading-out circuit in order to prevent position information in the cores frombeing destroyed by occurrence of spark. The fast signal from a photomultiplier which
triggers the high voltage pulser closes the gate for two microseconds until the storm of

Reset

Start

Posit ion information
strobing system

Fig. 1. An abbreviated block diagram of electric system inwire spark chamber.

___ ( Clearing voltage VCIHigh tension wires) High voltage VH( » VCI)1I

The 2nd clearing,~toge - Vcl

Position wires -ground potential
Uniform clearing f ield

[

_ VCI

CI -

(j

_ VCI - ( - VCI)[ C22dVCI _ [d -CI

Uneven high tension fiel d

VH

[HI=T

VH

[H2 =

[HI

2d = 2

Fig. 2. The effect of the 2nd clearing plate on theclearing and high tension fields.

93spark current becomes quiet. After this signal has been held for 5 jJ, sec by a delay
generator, the logic circuit is caused to reset and start readi ng -out. Als 0 a noise
picked up by sense leads was minimized by twisting each sense wire in order that they
are not exposed to the magnetic flux from the read -out and spark currents.
Residual ions existing outside of the gap between wire planes are not swept away
by a clearing field and bring about fault sparks, especially in the neighborhood of bothedges of wire planes. The other clearing plate was set parallel to wire planes at a
distance twice the wire gap from the high tension wire plane and given a potential ofequal magnitude but of opposite polari ty to the clearing voltage on the high tension
wires.
As seen in Fig. 2, the clearing field is distributed uniformly in the horizontal
direction, but the high tension field outside of the gap becomes half of its inside. Thus,
error sparks in the neighborhood of both edges are prevented.
Any trouble does not occur in the upper and bottom ends of the gap because ofsteep decrease of high tension field.
Electrical principle of the wire spark chamber is shown in Fig. 3 (a).
Theequivalent circuits of the chamber are shown in Fig. 3 (b) and Fig. 3 (c).
Thetransmission line from the high tension pulser has characteristic impedance of 50 Q .
Rl, R2, and R3 are varied appropriately to match the characteristic impedance and limit
spark current.
Tests were performed in the following three cases:
i)
ii)
iii)

R 1 = 0 Q.
R2 = r Q
R 1 = 50 Q , R 2 = r Q
Rl = 50Q , R2 =rQ

and R3 = 100 Q
and R3 = 100 Q
and R3 =2 kQ.

Here, r is the total amount of resistance due to a stainless steel wire, a conductive glueand contact resistance between them. The value of r has discrete distribution between
50 to 200 Q. The values of the high tension, the first and second clearing fields and the
He-gas pressure are fixed at 5.5 kV, +31 and -31 V and one atmosphere, respectively.
In the second case there appear no spark and no count because of decrease of effective
high voltage by one -third. In the third case there occur sparks and counts but noise islarger than in the first case. Increment of R2 by addition of resistance of 100 Q in thefirs t case induces further dis turbance of high tens ion pulse so that the information of
position stored in the cores is destroyed. The first case without modification is chosen
as a better combination.
A test of space -resolution is performed in a manner of Fig. 4 (a) and its res ult
is shown in Fig. 4 (b).
Operating conditions are the same as mentioned above excepta ) .---_---,

3

Conductr} R2

7f

ive~lue2C~
100.0.

1OOOpF ~Clearing
voltageI'-_ _---'

Fig. 3. Principle and equivalent circuits of the wire sparkchamber. a) shows principle. b) and c) areequi valent circuits in the absence and presence of
spark respectively.

94

Position wires (0.1 mm4> stainless steel)
Bross slit
with three holes at I mm in dia.
in interval of 10mm

High tension wires (0.1 mm<P stainless steel)? Plastic 5cent illators(3- roy 50 ur cefrom 90Sr

9 mm

800

600

<P[

I ~
2: ...1 J\.

:

in
air

~.._

VH = 5.5kV
PH. = 1 atm
Vcr" = 100V
VCI - =-100V30}l duralmine toilinHe-gas~~~:Jf -31i...i .~

in2 He-gasinair\..J ..

40 ----j

10 20 30 40 50(0)

pos i t ion (mm)

Wire

( b)

Fig. 4. A test result of spatial resolution with Model-I. a)
Source and slit system used. b) A result of spatial
res olution in this case.

!3-raysource90
from SrBross slit
. .
.
with a 1mm4> h 1
Pos Itlon wires~oewith memory cores

I

l

r

High tension wires

:

I

A
/.
.\

300

7

1

<J')
~

co

IT ~5mm

'"
8 200

~o~ ~

~7.5~
(0)

VH = 5.4kV
PHe = 1atm.
VC1+ = 100V
VCl- = -200V

400

Itwhm J

.r .\

100

I \~

1

~

.

O~~~~~~~~--

Wire position

(mm)

(0)

Fig. 5. A test result with Model-II. a) Source andslit system used. b) A res ult of spatial
resolution in this case.

that clearing voltages are changed into +100 and -100 V. Space -resolution of about 3
mm full width at half maximum was obtained.
In order to prevent extra spark, geometrical modification of the chamber was
performed. A model-II is the same as the model-I in principle. In the model -II,phosphor bronze wires of 0.1 mm diameter are soldered on both surfaces in a printed
circuit board with a thickness of 1.5 mm. A series resistance of 20 Q is inserted tothe input terminal of a high tension wire plate to limit the spark current. A test resultof spatial resolution is shown in Fig. 5 (b).
High tension voltage and He-gas pressure
are 5.4 kV and one atmosphere. Clearing voltages are +100 and -200 V. The model-IIshows remarkable characteristics for most part of sparks to localize at one wire.

95

Worse space -resolution of 5 mm in Fig. 5 originates from ' the property of the slit
system.
Counting rate of the system is governed by the dead time of the high tension pulser
which is about 75 m sec.

Reference
1)

J. Fujita and S. Takeda: IPCR Cyclotron Progr. Rep., ~ 68 (1971).

96

6-4.

Measurements of Ion Optical Properties ofA

Partie Ie analyzer by Partie Ie Beams

N. Nakanishi, S. Motonaga, S. Takeda, M. Hemmi,
T. Inoue, J. Fujita, and H. Nakajima

Measurements of optical properties of the magnetic analyzer were carried out by
two methods, the floating-wire method and the method using particle beams. The
former was employed in order to estimate roughly the position of horizontal focal line,
dispersion factor and incident angle to the focal line, and the latter was adopted inorder to obtain the relation of horizontal focal point to beam radius, solid angle anddispersion factor. A part of the results was already reported .1),2)
Proton beams from the cyclotron were analyzed in the accuracy of less than 0.1 %at 13.80 MeV, and scattered elastically in the direction of 14.75 0 by Au of 32.8 ,ag/cm 2
thickness. Nuclear emulsion was used as particle detector. Dispersion factors
projected on the focal line and momentum resolutions were estimated from the

LL

7.0

.'

c=
0
Vl

6.0

-.-.-.--r-.~

~

Q,/

.--.
..

0Vl

a

• •

5.0

TI

100

I

I

110
Radius120(em)

Fig. 1 . Dispersion factor vs. radius ofcurvature of beam.

c=

o

+J
~

o

3.0

Vl
Cl>

L-

E
~

~

c

E
2.0
o

~

T

I

100

120

110
Radius(em)

Fig. 2. An example of momentum
res olution vs. radius of curvatureof beam. Proton beam of 13.8MeV
energy was scattered elasticallyat an angle of 14.75 0 by Au -foil of
32.8 ,ag/cm 2 thickness and was
detected by nuclear emulsion on
the focal line.

97

measurements of focusing positions corresponding to the fields Band B + L1 B. Figures
1 and 2 show the dispersion factor and momentum resolution~ respectively. Solid angle
was also estimated tobe within the range from 3.1 x 10 - 4 sr to 6.1 x 10 - 4 sr when thedefining slits were set at an solid angle of 8.2 x 10 - 4 sr.
The relation between beam radius and focusing position was obtained to examine
the influence of the change of field distribution in magnetic fields ranging from 2700 to
3230 gauss for alpha beam from 210Po, from 4500 to 5250 gauss for 14 MeV protonbeam, from 4570 to 5550 gauss for 16 MeV alpha beam, and from 7440 to 8850 gauss for
40 MeV alpha beam. An example for the 14 MeV proton beam is shown in Fig. 3.
Systematic dependence on the field strength was obse rved. However it is so small that
we can not see it in the figure and can be neglected in the normal use.
The measurement was also done on the effect of hysteresis, that is, the change offocusing position due to different processes of field -setting to the same field strength.
Magnetic field was set in two ways. One was to set the exci ting current directly fromzero to the necessary value and the other was to set the current at the necessary value
after being kept at twice of it for 15 minutes. Maximum difference of 5 x 10 - 4 ofmomentum was observed.
120.0 .~

~.
E
u

~~
.~

110.0

.~.

~.

"

100.0

T
o

120.0

80.0

40.0

Distance along tocal plane(em)Fig. 3. Relation of the horizontal focusing pOint withthe corresponding beam radius in the field.

200 -

IOOMo

.~

( p,p' )~Ep = 13. 80MeV
8 lob=41.5°

E
E
N

x
:i
E
E

~ 100

o
V>
.....
C

::l

o

U

lD

0
~

N

0
0

ro

N

N

N

N

N

lDlJ)

(j)

lJ)~

0

0

f'-lD
N

("')<:j

N

N

lD

N

lD

ro

lJ)
N

f'--

(j)

0

N

N

N

c0

<:j
<:j

<:j

0

0

lJ)
("')

-

("')

I I
o ....~ .... , .....--<\ . .-.. 1>.:;: t~···../\j\ .-. )'.-"/':;;'." ·_J\}·-········.1: ;·A:_,. i; ....,...j.;. 00
6IIDista nce

along

focal

plane

(em ) '

Fig. 4. Proton spectrum of reaction 100Mo(p, p ')lOOMo. Energies of some excited levels
are also shown.

98

The proton energy spectrum for the reaction 100Mo(p, p ') 100Mo is shown in Fig.
4 in the excitation -energy range from 1.9 MeV to 3.2 MeV. The proton beam of 13 MeV
was scattered inelastically at an angle of 41.5 0 by a 100Mo-foil of 1.08 mg/cm 2
thickness and was detected by nuclear emulsion on the focal line.

References
1)
2)

S. Motonaga, N. Nakanishi, K. Matsuda, M. Hemmi, H. Ono, and Y. Awaya: IPCR
Cyclotron Progr. Rep., l, 77 (1969).
N. Nakanishi, S. Motonaga, K. Matsuda, S. Takeda, M. Hemmi, H. Nakajima, andY. Awaya: ibid., i, 96 (1970).

99

7.

RADIOCHEMISTRY

7-1.

The Behavior of Trace Amounts of 18F Atoms Trappedon Metal Surfaces

M. Aratani

In the course of studies on the charge spectrum of ions derived from the decay of
18p trapped on metal surface,!) it has become clear that the trapping of 18p on thesurface depends upon the chemical nature of the metal surface.
The metals employed for the trapping of 18p were aluminum, copper, zinc, andstainless steel. The radiofiuorine, 18p, was produced by the 160(3He,p)18p
reaction)A stream of oxygen gas was bombarded with 3He beams from the cyclotron
in an irradiation tube especially designed for this purpose. After the metal surfaces
had been treated with a series of cleaning processes, the metal plates (10 mm x 20 mm
x 0.5 mm) were exposed to the flow of bombarded gas at the outlet of the irradiation
tube. A part of the 18p in the gas stream was trapped on the surfaces of the metal
plates. After each plate had been exposed to the gas stream, the annihilation gamma
activities of 18p on each plate were measured by means of a scintillation counter. The
decrease in the activities of the trapped 18p with the time was measured with orwithout vacuum pumping. In the measurements with the vacuum pumping, the samples
were transferred to a chamber. The chamber could be evacuated down to 10-4 Torr ina much shorter time than the half -life of 18p. The counting rates of the samples were
followed for at least two half-lives of 18p. In the measurements without vacuum
pumping, the samples were kept in a desiccator and the counting rates of the samples
were measured in the same way as has been described above.
In every run of the measurements without vacuum pumping, the decrease in theactivity of the 18p on the metal surface as a function of the time was found to be linear
in the semilogarithmic plots, and the decay of the activity agreed wi th that of 18p. The
measurements with vacuum pumping, however, showed different results. The
difference was that the decrease in the activity of the trapped 18p, on the surface
samples wi th the time was not linear in the semilogarithmic plots in every run. The

Table 1.

Exhausted fractions (fE ) and res idual fractions(fR) of 18p atoms on trapping metals.

Trappi ng metal

fE

fR

Aluminum

0.16

0.84

Copper

0.86

0.14

Zinc

0.62

0.38

Stainless steel

0.14

0.86

100

1o4 r - - - -- - - - - - - - - - - - - - - - - - ,

Q)

+'

0'

o

c:

L

~o

0'
C

.......

L)

C

::J

o
U

102~--~---~--~~--~--~

o

60

120

180

240

o

300

60

120
Time

Time (min)

180

240

300

(min)

Pig. 2. Changes with time in counting
rates of 18p on copper plates
under vacuum pumping (thickline) and without it (thin line).

Pig. 1. Changes with time in counting
rates of 18p on aluminum
plates under vacuum pumping(thick line) and without it(thin line).

10 4 r --- - - - - -- - - - -- - - - - - ,Q).......
o
L

0'
0'

C

c:

.......

+'

C

C

::J

o

::J

o

U

U

o

60

120
Time

180

240

(min)

Pig. 3. Changes with time in counting
ra tes of 18p on zinc plates
under vacuum pumping (thickline) and without it (thin line).

300

1020~--~6~0--~1~20~-~1~80~-~2~4~0--~30·0
Time

(min)

Pig. 4. Changes with time in counting
rates of 18p on stainlesssteel plates under vacuum
pumping (thick line) and without it (thin line).

results are shown in Pig. 1 (aluminum), Pig. 2 (copper), Pig. 3 (zinc) and Pig. 4(stainless steel).
The linear part of each curve corresponds to the decay of 18p. The non - linear
part can be interpreted in terms of the stripping of a fraction of 18p from the metal
plates during the vacuum pumping. The strippable fraction can be estimated by thecalculation of (CO -NO)/CO' where Co is the total counting rate of the sample at t = 0,
and where NO is the counting rate obtained by extrapolating the linear part of theactivity curve of the sample to t = O. The fraction of 18p sticking on the surface after
the vacuum pumping is then NO/CO'101

The res ults demonstrate that the trapping of trace amounts of 18F on the metal
surface depends upon the chemical nature of the metal, and that aluminum and stainlesssteel are suitable metals for providing a stable deposition of trace 18F atoms on thesurface under a vacuum.

References
1)
2)

S. Yokoi, M. Aratani, and T. Nozaki: IPCR Cyclotron Progr. Rep.,~, 88 (1971).
T. Nozaki, Y. Tanaka, A. Shimamura, and T. Karasawa: Intern. J. Appl. Radiat.
Isotopes, 19, 27 (1968).

102

7-2.

A Mossbauer Spectroscopic Study of Chemical States of
119 Sn after the EC Decay of 119 Sb in Sb203 and Te02

F. Ambe, S. Ambe, and N. Saito

As a part of a series of investigations 1) of the chemical states of dilute impurity
atoms produced in solids by nuclear decay, the valence state of 119Sn after the EC
decay of 119Sb was determined in Sb203 and Te02 by Mossbauer emission spectroscopy.
The 119Sb (38.0 h) and 119mTe (4.7 days) were produced by the p- and a irradiation of tin plates respectively. The nuclides were separated from tin and were
purified radiochemically. 119Sb203 was obtained by the hydrolysis of a 3M HCl
solution of 119Sb (III) with NH40H. The precipitate was dehydrated at 1200 C andsublimed in a vacuum at SOOOC. 119mTe02 was prepared by neutralizing an alkaline
solution of 119mTe(IV) wi th 2 M acetic acid. The precipitate was dried at 120 0 C in air.
The samples were identified by their Debye -Scherrer patterns. The 119mTe02
samples were let stand in liquid nitrogen until the 119Sb attained a state of radioactive
eqUilibrium with 119mTe. The Mossbauer emission spectra of 119Sn in the 119Sb203
and 119mTe02 samples were measured at liquid nitrogen temperature against BaSn03'
Typical spectra thus obtained are shown in Fig.!.

000

100

en

c:

98

<1.l

+-'

c:

<1.l100~o~~~~~·~

>
+-'

o

<1.l
cr::

(b) 113mTe02

98
SnO

1ldJ U

Sn02~ --------~------~------~------,,~

-10

-5

Relative0
ve locity+5+10(mm/sec)

Fig.!. 119Sn -Mossbauer emission spectra of(a) 119Sb 0 3 and (b) 119mTe02 at 78 ±2
1 0 K against BaSn03 at 296 ± 2 oK. In
the abscissa a velocity of approach istaken positive.

103

The emission spectra of 119Sb203 in the cubic modification are dominated by twolines, which can be identified as a quadrupolar doublet due to Sn(II), with oxygen ionsas ligands (see Fig. 1 (a». .
The identification is based on the fact that the isomer
shift, 2.91 mm/sec, and the quadrupole splitting, 1.90 mm/sec, do not differ much fromthose of the tetragonal and rhombic SnO)
The subsidiary peak close to the zero
relative velocity can similarly be assigned to a Sn(IV) state. These aSSignments allow
us to conclude that the 119Sn atorps produced by the EC decay of 119Sb203 are
preferentially. stabilized in the Sn(II) state, if the recoilles s fraction is assumed to beof the same order of magnitude for the Sn(II) and Sn(IV) states. In case of the Sb203
samples, which had not been sublimed, the fraction of the Sn(IV) line was much larger
than in the sublimed samples, although the Sn(II) doublet was still dominant.
The 119Sn produced by the successive EC decays of 119mTe via 119Sb in the Te02
matrix gave a broad emission line attributable to a Sn(IV) state (see Fig. 1 (b». The
isomer shift, 0.19 mm/sec, is slightly higher than the corresponding value for Sn02'
The quadrupole splitting, computed on the ass umption that the peak is an unresolved
symmetric doublet of quadrupolar origin, amounts to 0.9 mm/sec. No line was detected
in, the region of Sn(II) wi thin the limits of the sensitivity of meas urement. Although thevalence state of 119Sb in the 119mTe02 can not be determined by Mossbauer or otherconventional physical techniques, a radiochemical determination has shown that about
sixty percent orthe 119Sb is in the Sb(III) state, and the rest, in the Sb(V) state, after
the EC decay of 119mTe in Te02.3) Summing up these observations, it can be concluded
that a large part of the 119Sb atoms were in the Sb(III) state, presumably with oxide ionsas ligands, after the EC decay of 119mTe in the Te02' and they turned into 119Sn in thetetravalent state with the second EC decay. This contrasts with the results on
119Sb203, in which the majority of 119Sn was in the Sn(II) state after the decay of
119Sb(III) with oxide-ion ligands. These observations suggest the importance of thematrix in determining the final valence state of 119Sn . The appearance of 119S n only
as Sn(IV) in Te02 is in accord with the similarity of the crystal structures of Te02 andSn02 (rutile type) and the fact that the stabilization of 119Sn in the Sn(IV) state requires__ ___no charge compensation, as in the case of the IT in 119mSn0 2 .

References
1)
2)
3)

F. Ambe, H. Shoji, S. Ambe, M. Takeda, and N. Saito: IPCR Cyclotron Progr.
Rep., 1,115 (1970); ibid.,~, 85 (1971); Chem. Phys. Lett., 14,522 (1972).
J.D. Donaldson and B.J. Senior: J. Inorg. Nucl. Chem., 31,881 (1969).
S. Ambe, F. Ambe, and N. Saito: IPCR Cyclotron Progr. Rep., Q., 104 (1972).

104

7-3.

A

Radiochemical Study of Oxidation States of 119Sb after them
EC Decay of 119 Te in Te02 and H6 Te06

S. Ambe, F. Ambe, and N. Saito

Although considerable information has already been accumulated concerning thechemical effects of the IT and the ;9 - decay in tellurium compounds, no investigation
has ever been reported on the chemical consequences of the EC decay of tellurium. We
have now studied the oxidation states of 119Sb (38.0 h) arising from the EC decay of
119mTe (4.7 days) in tellurium dioxide and telluric acid.
The procedures for producing 119mTe and for preparing 119mTe02 have been
des cribed elsewhe re .1) H6 119mTe06 was prepared by the oxidation of the solid
119mTe02 with KMn04 in dil. HN03 and was recrystallized from dil. HN03 , and thenfrom water wi th the aid of ethanol. The product was dried under a vacuum over P2 0 5
and CaO. The samples were kept at room temperature, OOC or liquid nitrogentemperature for twelve days or more to allow to decay the 119Sb produced from 119mTe
during the procedure of preparation of the samples.
119mTe02 (3 "-' 10 mg) was dissolved in 6 M HCl containing 3 mg each of Sb(III)and Sb(V) carriers. The solution was immediately diluted to 1.5 M in HCl.
H6119mTe06 (50~100mg) was dissolved in 1.5 M HCl containing the carriers.
The 119Sb in the Sb(III) and Sb(V) states was separated by an anion exchange
procedure .2) The 119Sb in each fraction was precipitated as Sb2S3 from the solutions
with H2S and was collected on a sheet of glass filter paper. The 119Sb-radioactivity(23.8 keY r -rays and Sn KX -rays) of each fraction was measured by means of a 2 -mm
NaI scintillation counter connected to a multi -channel pulse -height analyzer.
The results on solid 119mTe02 are shown in Table 1. In this compound, 119Sb
was found in both the Sb(III) and Sb(V) states, the distribution in the Sb(III) state beingslightly higher than that in the Sb(V) state. As can be seen in Table 1, the 119Sb-

Table 1.

Oxidation state of 119Sb after the EC decayof 119mTe in solid Te02 and H6Te06'

Materials

Te02

H6 Te 06

Temperatureof storage(OC)

Sb(III)

Sb(V)

(%)

( %)

196

59 ± 141 ± 12366 ± 3

34±3

- 196

5.0 ± 0.8

95.0±0.8

02.2 ± 0.1

97.8±0.123

1.6±0.2

98.4±0.2r105

radioacti vity in the Sb(III) fraction increased with an · increase in the temperature ofstorage. This observation suggests that the trivalent state is more stable for 119Sb in
the solid 119mTe02 than is the pentavalent state.
The results on solid H6119mTe06 samples are also gi ven in Table 1. In thismaterial, most of the 1I9Sb was found in the Sb(V) fraction, reflecting the higher
oxidation state of I19mTe in telluric acid. In contrast with the case of Te02' the 119Sb
in the Sb(III) fraction showed a significant decrease with an increase in the temperatureof storage. It can be cO,ncluded, therefore, that the pentavalent s tate is more stable
than the trivalent state for 119Sb in H6119mTe06'
In the H6I19mTe06 samples stored in the form of solutions in water and 1 M KCl
without carriers, 30 %and 9 % of 119Sb were found, respectively, in the Sb(III) fraction.
The observed values for distribution in Sb(III) are considerably higher than thecorresponding values for the H6I19mTe06 samples stored as a solid. These res ults
can be interpreted on the basis of the absence of the effect of lattice in solutions. The
fact that, in a solid, the 119Sb in the Sb(III) state decreases with an increase in thetemperature of storage shows that the lattice of telluric acid favors the stabilization of
1I9Sb in the Sb(V) state, which has an oxidation state closer to the tellurium of theparent compound than does the Sb(III) state. Since there exists no such an effect oflattice in solutions, a greater part of the 119Sb is considered to have been allowed tostabilize in the Sb(III) state.

References
1)
2)

F. Ambe, S. Ambe, and N. Saito: IPCR Cyclotron Progr. Rep., Q, 102 (1972).
T. Kambara, K. Hasegawa, and T. Nakamura: Rep. Fac. Sci. Shizuoka Univ., 15,
51 (1970).

106

7-4.

Radiochemical Studies on Carbon, Nitrogen, andOxygenIn

Sem iconductor Silicon

T. Nozaki, Y. Yats urugi, and N. Akiyama

By the following three methods, the concentration and behavior of carbon, nitrogen,and oxygen in semiconductor silicon have been studied: (1) charged particle activation
analysis, (2) infrared spectrophotometry calibrated by charged particle activation, and(3) a special tracer technique. We have already published some of our results,l) "-'4)and in this report the works done in 1971 and 1972 are described.
In this period, (1) the precision and accuracy for the activation analysis of the
carbon was examined closely in order to obtain more reliable calibration curve for the
infrared spectrophotometry of carbon in silicon, and (2) the solubilities of nitrogen andoxygen in solid and liquid silicon at its melting point were determined with moreaccuracy. The infrared calibration curve for carbon in silicon is given in a separate
paper,S) together with its validity range, precision, accuracy and some remarks
necessary in the practical infrared determination. Table 1 shows the solubilities forcarbon, nitrogen, and oxygen as well as their equilibrium distribution coefficients
between solid and liquid silicon and their atomic dimensions. Figures 1 and 2 show
the phase diagrams for N -Si and 0 -Si sy stems in extremely low nitr ogen 0 r oxygen
concentration ranges. Detailed description about these data together with thermodynamical discussions on them will be published in near future. 6 )Table 1.

Solubilities and equilibrium distribution coefficients of carbon,
nitrogen, and oxygen in silicon at its melting point and their atomic
radii and tetrahedral radii.
CarbonNitrogen

Oxygen(at ./cm 3 )(3.2 ± 0.3) x 10 17(4.5 ± 1.0) x 1015

(2.75 ± 0.15) x 10 18(atomic fraction)(6.5 ± 0.5) x 10- 6(9 ± 2) x 10- 8(5.6 ± 0.3) x 10- 5(at ./cm3 )(4.5 ± 0.5) x 10 18

7 x 10 18(2.20 ± 0.15) x 10 18(atomic fraction)(9 ± 1) x 10- 5

1.2 x 10- 4(4.5 ± 0.3) x 10- 5

0.07 ± 0.01

7 x 10- 4

1.25 ± 0.15

Atomic radius (A)

0.77

0.53

0.60

Tetrahedral radius (A)

0.77

0.70

0.66

Solubility in solid

Solubility in liquid

Equilibrium distribution
coefficient107

Li ct.
Q)

L

Si+Liq,.

~

+-'

~
Q.l
a.

E

Q.l

\-

Si

!

!

!

4

6

8

~

I

10 18 ot~ /cm 3

10 15 ot./cm 3
Nitrogenconcentration

Fig.!. Phase diagram of N-Si system in
extremely low nitrogenconcentrations.

L i q, .

Liq,. + S iO

Q.l

I.....
:::l

+-'

o

I.....
Q)a.
E

Si + SiO

Q.l

I-

o

1
2
3
Oxygen concentration (10 18 at./cm3 )I

4Fig. 2. Phase diagram of O-Si system i n
extremely low oxygen
concentrations.

Studies on the following subjects are either under way or under planning: (I)infrared spectrophotometry for oxygen in silicon as calibrated by charged particle
activation, (2) relationship between the carbon monoxide content of the ambient and theconcentrations of carbon and oxygen in molten silicon, and (3) effects of carbon insemiconductor silicon on its electronical properties.

References
I}
2}
3}
4}
5}
6}

T. Nozaki, Y. Yatsurugi, and N. Akiyama: J. Radioanal. Chern., 1,87 (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: Intern. J. Appl.
Radiat . Isotopes, 22, 602 (1971).
T. Nozaki, Y. Makide, Y. Yatsurugi, Y. Endo, and N. Akiyama: Bull. Chern. Soc .
Japan, 45,2776 (1972).
Y. Endo, Y. Yatsurugi, N. Akiyama, and T. Nozaki: Anal. Chern., 44, 2258 (1972).
Y. Yatsurugi, N. Akiyama, Y. Endo, and T. Nozaki: Submitted for publication in
J. Electrochem. Soc.

108

8.

RADIATION CHEMISTRY AND RADIATION BIOLOGY

8-1.

Radiolys is of Binary Mixtures of Tetrahydrofuran
and Benzene in HighLET Region

M. Matsui, T. Karasawa, and M. Imamura

Binary mixtures of tetrahydrofuran (THF) and benzene were subjected toradiolyses with 20 MeV 4He - and 80 MeV 14N -ions. Variations of the yield ofhydrogen, a major radiolysis product, in the 4He -ion and 14N -ion radiolyses are shownin Figs. 1 and 2, respectively, as a function of the electron fraction of benzene. The
general patterns are similar to that observed in r -radiolysis shown in Fig. 3,1) i.e., anenergy transfer from the precursor of hydrogen to benzene seems to take place,
resulting in the reduction of the yields from those expected in the absence of any
interaction between the two components. (These expected values are to be on the lines
connecti ng G -values of pure THF and benzene as shown in Figs. 1, 2, and 3)
A previous study 2) on r -radiolysis of a binary system of THF and furan also
exhibited the similar beha vior, and it was concluded that the charge transfer from THF~
the precursor of hydrogen, to furan does take place.
In the present THF -benzene system, it can also be assumed that the precursor ofhydrogen is THF+ and the charge transfer to benzene would take place to reduce theyields of hydrogen. The experimental res ults supporting this ass umption are des cribed
below.
First, the yields of hydrogen in r -radiolysis of pure THF are not affected in thepresence of radical scavengers, indicating that the precursor should be ionic or exci ted
species. Second, carbon monoxide, the yields of which are not affected by radical
scavengers, was concluded to be formed predominantly from excited species ,2) and its
yields in the THF -benzene and THF - furan 2 ) systems do not show any deviation fromlinearity unlike those of hydrogen. Finally, the behavior of G(H 2 ) is quite similar tothat observed for the THF -furan system as mentioned above.
84~----------------------------~

N

C\J

:r:

I

EIe ctron fro ct ion ot benzene

Fig. 1. Variation of G(H2) wi th electron
fraction of benzene in 4He - ionradiolys is.

Electron tract ion of benzene

Fig. 2. Variation of G(H2) with electron
fraction of benzene in 14N - ionradiolysis.

109

4~--------------------------~

1.0

xElectron fract ion of benzenezFig. 3. Variation of G(H2) wi th electron
fraction of benzene in r -radiolysis .
According to Hardwick,3) let x be the electron fraction of THF, and let z be theapparent electron fraction of THF as indicated by the measured value of G(H2) (Cf. Fig.
3), then the amount of THF which transfers energy is (1- z) - (1 - x) = x - z. The
fraction of THF molecules absorbing energy, and which subsequently transfer thisenergy, is (x - z)/x. The limiting values of (x - z )/x and the decreasing hydrogenyield, LlG(H2), at the higher concentration region of benzene for r , 4He, and 14N
radiolyses are listed in Table 1.
Table l. Yields of total ionization of THF obtained for the radiolysesof THF -benzene mixtures with r, 4He, and 14N.
Radiation

Mean LET0(eV / A)

LlG(H2)

Limiting(x-z)/xG(totalionization)

r

0.02

2.2

0.70

3.1

4He

6.5'"'-'7.0

2.4

0.75

3.2

14N

43

2.0

0.65

3.1

Using these values and assuming that all the hydrogen is produced from THF+,
one can estimate the yields of total ionization of THF as listed also in Table 1. Theseres ults imply that G(total ionization) is invariant irrespective of the nature of radiations
or LET. Large increases of G(H2) which are generally observed for radiolyses ofliquid organic compounds in a high LET region may therefore be not a.scribed to theincreasing ionization resulting from charge exchange, energetic secondary electron
production or other events by heavy ions.

References
1)
2)
3)

M. Matsui: Bull. Chern. Soc. Japan, 39, 1640 (1966).
M. Matsui and M. Imamura: Abst. 12th Conf. Radiat.Chem., Nagoya, p. 57 (1969).
T. J. Hardwick: J. Phys. Chern., 66, 2132 (1962).

110

8-2.

LET Dependence of Spatial Distribution of Free Radicals
in Irradiated Crystalline Eicosane

K. Kimura, M . Kikuchi, * M . Mats ui, T. Karasawa,
M. Imamura, Y. Tabata, * and K. Oshima *Electron spin resonance studies have been made on the spatial distribution and its
dependence on linear energy transfer of free radicals produced and trapped in a
crystalline n -eicosane (C20H42).
Only a few studies have been reported so far on the similar subject with aminolacids ) and other solids,2) 'and no substantial differences in the spatial distribution offree radicals due to LET have been found.
Sliced single crystals (45 x 45 x 1 mm) were subjected to irradiations with 23.3
MeV 4He, 85 MeV 12C, and 81.5 MeV 14N ions at low temperatures in the vicinity of
80 OK. Irradiations were also carried out using 60Co r -rays for comparison. ESR
measurements were done employing 100 kHz frequency modulation at several
temperatures between 77 and 250 0 K. Upon r -irradiation, the single crystal of neicosane gave ESR spectra having well-separated and sharp hyperfine structures which
can be attributed to alkyl radicals in the weak spin -spin interactions .
0°

I

~
,

';

I

/

r
/
I /
1/

1/

'Ho

\

\

r\
I q
I ' V / \\
I /"
\

I

I /

~

'

I

\

II
I I

0

/

\

\

',I

\

(/

,, ~~

' \1

60°

(a)

90°
1\
\

~o

I,

1\

'

I "- ,
"I
"I
"I

,

\\
\
\

I

II I

"

,

I
)C.

I

//

/ "

,

I

I

,/

I
I
I

"-

0 1

""

/ I
I

/

/

I

I
I

\

I

"

/ ;:::.

30°( b)

L-~__~__~__O-~~~__~~~~__~~O°

-80

0

40

GAUSS

Fig. 1. Variations of hf coupling constants with
angles of static field EO to the surface of neicosane.

* Department of Nuclear Engineering, University of Tokyo.

III

Figure 1 shows variations of hf coupling constants of alkyl radicals with angles«() of static field Ho to the crystal surface for two cases (a) and (b): (a), HO is fixed
perpendicular to a crystal axis of growth and (b), HO is at variable angles to this axis.
When HO intersects with the surface at a right angle, six lines are assignable to fi ve
equivalent a and jJ protons of a coupling constant of 34.8 gauss; when HO makes anangle of 0 0 wi th the su,rface and 90 0 with the axis (case a), ten lines to on<: a proton of
AalSO = -22.4 and Aadlpol = 8.9 gauss and four equivalent Ii protons of AjJ1SO = 34.8
gauss; when HO make.s an angles of 0 0 wi.th both the surface and axis (case b), ten lines
to one a proton of AalSO = -22.4 and Aadlpol = 1.2 gauss and four equivalent Ii protons
of ApiSO = 34.8 gauss.
In Fig. 2 are shown the spectra recorded at 77 0 K for samples irradiated with 4He
and 12C ions as well as with r -rays (case b, (j = 0 0 ). Apparently, linewidths of thespectra decrease on going from r to 12C -ion irradiation. There exists an relatively
strong dose effect on the lineshape and linewidth as shown in Fig. 3. Therefore,
absorbed doses in the present study were chosen to be so low as not to give rise to theoverlapping of ionization tracks.
A variation of the ESR spectra with temperature is shown in Fig. 4, in which
spectra were recorded at 77, 116, and 1980 K for a sample irradiated with 12C ions at
80 0 K (case b, (j = 0 0 ). It is apparent from Fig. 4 that as a temperature of the sample
is increased the intensity of the spectrum decreases, while its sharpness increases;
the spectrum recorded at 1980 K seems similar to that obtained by r -irradiation andrecorded at 77 0 K.

Irradiated with r (- . - .), 4He( - - - -), and 12 C (_).
Dose: 1.68 x 1021 eV for r ; 2.3 x 10 1g eV for 4He; 2.7 x
10 19 eV for 12C. Spectra recorded at 77 oK. Case b,(j = 0°. Absorption lines due to Mn2+ are indicated byarrows.
Fig. 2. ESR spectra of irradiated n -eicosane.

•

112

Spectra recorded at 77 oK. Case b, () = 0°. Dose: - - ,2.7 x 101g e V; ----, 1 x 1020eV ; -. -.,4.3 x 1021 eV.
Fig.3. Variations of ESR spectra with radiation dose.
Irradiated with 12C.

Irradiated with 12C to a dose of 2.7 x 101g e V.
Temperature: - - , 77 0 K; -----, 116°K; - ' -', 198 0 K.
Fig. 4. Variations of ESR spectra with increasing temperature .

•

113

Such a variation of spectra is not due to a motional narrowing because noreversible variation of spectra was observed even if the sample was cooled back tolower temperatures. Therefore, the spectrum disappearing by increasing temperature
is only a component having broad linewidths. In fact, by subtracting the spectrum
observed at 116 or 19So K from that at 77 o K, one can obtain a broad spectrum similar tothat obtained with the sample irradiated to a high dose.
From these experimental results, it may be concluded that the ESR spectra of 12C
or 14N ion -irradiated samples recorded at 77 0 K are superimpositions of components
ha ving broad and sharp linewidth. The broad one is regarded as being due to a strong
spin -spin interaction between closely distributed radicals. These radicals readily
combine with each other as the temperature is increased, resulting in the disappearenceof the broad component of the spectrum. The sharp component may therefore beconsidered to be due to sparsely distributed radicals, which is a principal mode in ther -i rradiation.
Preliminary estimate has been made of the relative number of radicals distributed
densely and sparsely. More quantitative studies are in progress.

References
1)
2)

T. Henriksen, P. K. Horan, and W. Snipes: Radiat. Res., 43,1 (1970).
Yu. D. Tsvetkov and A. M. Raitsimring: Radiat. Effects, 1.., 61 (1970).

114

8-3.

lET Effects on Bacterial Cells

A. Mats uyama, T. Takahashi, T. Karasawa, K. Igarashi,
F. Yatagai, and Y. Kitajima(1)

Determinations of LET effects on cellular radiosensitivities of bacteria

Log -phase cells of g. coli Bs -1 and spores of a thymine requiring mutant of B.
subtilis 168 were irradiated with charged particles such as a -particles, carbon-,nitrogen -, and oxygen -ions to determine the LET dependence on radiosensitivity of thesebacterial cells. As previously described,!) bacterial cells spread on a membranefilter (Millipore filter type HA) which was placed on a wet pad were exposed to ion
beams in air. Using a biological irradiation unit, the sample was swung vertically andhorizontally in a plane perpendicular to the beam over a square area of 24 x 24 mm
during irradiation for the dose uniformity. Since the faster rate of the swinging cycle
was employed, a variance of survival data which might be due to the fluctuation of beam
intensi ty was reduced.
The res ults obtained are shown in Figs. 1---4. All s urvi val curves were of an
exponential type. With respect to LET dependence on cellular radiosensitivity, it
should be noted that values of radiosensitivity, 1/D37, simply decreased with increasing
total LET in the case of g. ~oli Bs -1 (Fig. 2), while those of li· s ubtilis spores revealed
a maximum at about 12 eV /A of total LET, followed by the decrease in higher regions(Fig. 4). In the latter case (li. subtilis spores), where the shape of survival curvesindicates the one-hit type, the increase in cellular radiosensitivity with increasing LEToin the region of the LET less than 12 eV / A suggests that one effective lethal hit requires
multiple events as charged particles traverse the target in a spore. It must be pointed
out as a pregnant fact that, in Fig. 3 illustrating a relationship between the energy ofcharged particles and inactivation cross section for spores, there can be seen asignificant shift of the effective cross section (Seff) for nitrogen ions (0.17 ,a2) from the
maximum plateau of Seff for a -particles (0.13 ,a2) in the low -energy region (less thanabout 1 MeV /amu). Because biological effects in these low energy region do not or
hardly involve those due to 0 -rays, this shift may suggest an additional possibility of
spore inactivation due to the smaller targets other than DNA molecule or spore -specificconformation of DNA. Further investigations are now undertaken in this laboratory to
elucidate this problem.
(2)

Analysis on the inactivation model for E. coli BS-1

Since survival curves of E. coli Bs -1 were of the exponential type, from theviewpOint of one -hit model in the target theory, the relationship between Seff and LET
can be Simplified as follows:

Seff = So {I - exp (-k· L) }(1)

where So is the geometrical cross section, L the total LET, k a constant. As seen in
Fig. 5, theoreticar curve (1) indicates a good agreement with experimental one, andusing the least -squares method (Grid search method), parameters So and k aredetermined as follows:1150; a - particle

1.0
0.9
0.8

0

(); C- ion.;O- ion0; N-ion

0E. coli B 5-1

0
0

0
0

()

0.7

0

0

0

()

()

()

~0.6

:t 0.5(f)

f 0.4..... .....

......

.....

0.3
0.4

0.6

0.8

1.0

-

Energy.......

,,......

7.0(MeV/omu)

Fig. 1. Effective inactivation cross section (Seff) of E.
coli Bs -1 as a function of energy per nucleon(MeV /amu).
0.8
0.7

0.6
0.5

®

1:)

o

®

~ 0.4
....

c5
0.3
.......
0.2

®®

®

®

® ()()

G:J 0

®

~cx5J

0.1

'i3~6Qo-Total LET(eV/A)

Fig. 2. Radiosensitivity (1/D37) of E. coli Bs -1 as afunction of total LET.
0.30
0.20
0

0.15
®

0
® ®

0

0

~

0

0

0

0

0

~

0. 10
;::; 0.08::t...

0

®

~

0.06

®

I 0.04

(f)

§

®
®

0.02 -

0 .01L.,---...."L...,-~=-----,-L=----,..J.,,--~=---~~---,-J

0.4

0.6

0.8

1.0

1.5

2.0

3.0

4.0

-Energy (MeV/omu 1

Fig. 3. Effective inactivation cross section (Seff) of ~:subtilis 168 thy-ind -leu- (MY2YIU2) spores as afunction of energy per nucleon (MeV /amu).

0.04

1

O.o5 f-

1

@

~

-

4 6 8 110

@

@

@

@

@

0
00
0

~O
00

1
1
20 30 40 6 0 80100
Total LET (eV/ A)

@

@

200

/

/

- Total10
LET( eV /A)

15

(C)

(8 )

(A)

20

io= 1 k= 1/4
io=2 k= 1/4
io= 3 k=I/ 4

Fig. 6. Seff - total LET curve calculated by equation (3).

O. l f-- /

I 0.2

(.f)

~ 0.3

~

0.5

0.5

(eV/A)

15

20

0.1

-

10
Total LET(eV/A)

(A)

15

(C)

( 8)

jo=1
jo=2
jo= 3

20

k=I/4
k= 1/2k = 3 /4

Fig. 7. Seff - total LET curve calculated by equation (4).

(f)

~ 03

;;- 0.4
:::t.

0.6

0.6

0.4 .-

LET

Theor itico l
Experimento I

Fig. 5. Relationship between effective inactivation crosssection of];. coli Bs -1 and total LE T .

- - Totaloo@Fig.4. Radiosensitivity (1/037) of B. subtilis 168 thy-indleu - (MY2Y 1U2) spores as a function of total LET.

00.01 f-~ oJ~ 0.03

"0

I

1

0.06

I--'
I--'

Q\

@

117

So

0.585 ± 0.0697

k= 0.249 ± 0.0488(.a 2)The value of So' 0.59 .a 2, is appreciably smaller than the geometrical crosssection So, 1.1.a 2 , estimated from the electron micrograph, and this fact may suggestthat Seff is implicated with the repair ability for radiation damages in the target. If
the DNA in a cell is the target molecule, more explicit description (2) on the inactivation
mechanism is obtained by introducing the "microdose concept" to the target theory.
jo -1
S eff = So (1 - };j=o
f j = (£/W· L)

f

fj )

! exp (-C /W· L)(2)where f j is the probability that a track gives j primary events, jo the minimum numberof primary events required for one decisive event in a target,* W the mean energy per
primary event. f is the mean thickness of the target and consequently (f/W.L) is themean number of primary events occurred along a track. In the case of jo = 1 and k =.e /W, formula (2) is consistent with formula (1). Therefore, by applying formula (2) tothe experimental results, two different inactivation models can be suggested, which
define the repair ability factor (1 - P) with different ways. P is the probability of theunrepaired radiation damage, where the whole damage is normalized to 1.
In the first inactivation model, on the assumption that the whole DNA (thegeometrical cross section of which = S~) in a cell is the target, P could be defined asfollows:(3 )Three different calculated curves are shown in Fig. 6. The curve A .indicatesthe best fit for the experimental data. If curve A is adopted, the experimental results
give P = 0.39 and W = 170 eV.
In the second model, hypothesizing that more small unit of DNA (the geometricalcross section of which = So) in the cell is the target, P could be defi ned as follows:(4)
where Ws is the energy required for producing a single -strand break in DNA and Wg
the gamma energy absorbed in DNA of a cell irradiated with a dose specified by 037'
Three different cases are shown in Fig. 7. If curve A is adopted, the experimental
results give f = 6.4 A. In the first model, it is noto clear what is a decisive event in atarget and in the second model, the value of .e (6.4 A) appears too small to compare itwith the size of DNA strands. However, the possible contribution of any other targets
besides DNA should be taken into consideration for establishing the most plaUSible
inactivation model.
()* In general, primary ionization and excitation may be considered as primary events,
and if single - or double -strand breaks in DNA remain irreparable, they arereferred to as decis i ve events.

118

(3)

Sedimentation analysis on DNA of E. coli BS-l

In order to determine the LET dependence on a ratio of single breaks to double
break in bacterial DNA and a rate of the DNA repair, log-phase cells of ~. coli Bs -l
and M. radiodurans labeled with 3H -thymidine in advance have been irradiated withdifferent types and energies of charged particles, and subjected to the sedimentation
analysis before and after the postirradiation incubation. Although determinations have
not yet been completed, it has been observed that the rate of the DNA repair at high LET(44 MeV nitrogen ions) was appreciably reduced even in a radioresistant bacterium M.
radiodurans.

Reference
1)

A. Matsuyama, T. Karasawa, S. Kitayama, and R. Takeshita: IPCR Cyclotron
Progr. Rep., 1, 101 (1969).

119

9. SOLID STATE PHYSICS

9-1.

Positron Annihilation In Ferromagnetic Nickel

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

Positron annihilation in ferromagnetic nickel single crystals has been studied.
About 500 mCi 90Nb positron sources were obtained by irradiation of Zr targets in thecyclotron. The detailed experimental procedure was described by the authors .1), 2)
Figure 1 shows the observed angular correlation curves for the .CI00J orientationand for the [110J orientation, respectively. The curves marked Field -2 were obtained
under the condition that- the direction of the magnetization of the specimen was parallelto the direction of the polarization of th~ positron spins. The curves marked Field-lwere obtained by reversing the direction of the magnetization of the specimen. The
curves are normalized to give an equal area.
The smoothed curves drawn through the experimental points were obtained byevaluating at {)i the least-squares polynomial of degree 3 relevant to the five successive
pointsN ({)i +k), ()'i +k, k = -2; -1, .... 2J.

l

N (e) in arbitrary ,units1 -Ni (100) Field-l2 -Ni (110) Fie ld -1

3 -Ni (100)

4 -Ni (110) Field-2

Field-2

2

3
4

-5

0

Fig. 1. The angular correlation curves for(100) and (110) nickel crystals.

120

Ni(100) Field-2

o

5

10

15mrad0Ni(110)Ni(100) Field-1o5Field-loFig. 2. "Differentiated curves" obtained by differentiating
the angular correlation curves shown in Fig. 1.

In order to find some characteristics of the angular correlation curves, thesmoothed curves are numerically differentiated. The differentiated curves are shownin Fig. 2.
The statistical error of each point on the smoothed curves is about 0.7 %and is
not small enough to be used to see the effect of reversing the direction of magnetizationof the specimen. Therefore, the sectional area under the smoothed curve is calculated
at an interval of about one milliradian and from this area an averaged value of N( (), ()being taken as the middle point of the interval, is determined. The differences at each() by reversing the direction of magnetization are plotted in Fig. 3.
The observed features of the correlation curves can be interpreted qualitatively
on the bas is of the energy band structures in the ferromagnetic nickel calculated by
Connolly.2) The detailed report will be published elsewhere shortly.

121

Difference curve(Field - 2) - (Fie ld - 1)

Nitll0)

4

mord

4

Ni (100)

2
O~~~~~~+-~~~~--­

mord

-4

Fig. 3. "Difference curves" showing
the change of the correlation
curves on reversal of theapplied magnetic field.

References
1)
2)
3)

N. Shiotani, S. Ambe, T. Okada, and T. Karasawa: Japan. J. Appl. Phys., 11,412(1972).
N. Shiotani, T. Okada, H. Sekizawa, S. Ambe, T. Mizoguchi, and T. Karasawa;
IPCR Cyclotron Prog. Rep. 2, 105 (1971).
J. W. Connolly: Phys. Rev., 159,415 (1967).

122

9-2.

Point Defects in Irradiated Copper and CU3Au

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

The increased resistivity of irradiated f.c.c. metals shows distinctive recovery
below SOK (stage 1), then decreases gradually over a wide range of temperature (stageII) and shows again a fast decay near: room temperature (stage III). The assignment ofpOint defects behavior to each stage is a difficult problem and has given rise to avariety of interpretations for about 20 years.
The irradiation study of an ordered CU3Au alloy and a pure copper is being
performed in this laboratory)
The use of ordered alloys is expected to give
additional information which cannot be obtained by the studies of pure metals, because
the physical properties of ordered alloys are changed drastically by the change of thedegree of order induced by atomic exchange replacements, while those of pure metals
are not affected by atomic replacements.
(1)

Stage III annealing

A decay of the resistivity of Cu is caused by a decrease of the number of defects,
while that of CU3Au by a decrease of the number of wrongly sited atoms. As theordering replacements of atoms are caused by the defect migration, the decreasingrate of wrongly sited atoms is determined by a number of visits of defects to them,which is in proportion to the concentration of migrating defects (n), the number of jumpsof them (j), and the concentration of wrongly sited atoms (D). Thus the rate equation of
the stage III annealing of CU3Au is written as~~ = -njD.
As for n, its decay is caused by the recombination annihilation of interstitialatoms and vacancies, in which the number of migrating defects always equals to that of
the waiting counterparts (though it is not certain which are migrating in this stage), sothat the decay rate of the concentration of them obeys the 2nd order reaction kinetics
as
dn
2.
dt
= -n ]g,where g is the number of effective sink sites around waiting defects .
equa tions it can be derived that

From thesenino = (DIDo'·
In the irradiation experiments of aluminum a radius of sinks acting in the stage
III annealing was estimated to be around 2 atomic diameters ,2) from which the value ofg is deduced to be about 30.
The curves of n presented in Fig. 1 were calculated with this equation and theexperimentally obtained curve of D)
It can be fitted to the experimentally obtained
one for pure copper by taking g to be about 20, which is close to the above referredvalue.

123

1.0 r - - = = : : - - - - - - - - - - - - - - .

'"CI

~
0

cu
'C
C
0

-;

0.5

c:

c

0

U
0

~

260

280

300

T(°K)

Fig. 1. Isochronal annealing curves ofdefect concentration in CU3Au
calculated from the isochronalannealing curve of the concentration of wrongly sited atoms.
(Open circles indicate the values
obtained experi menta 11 y for StageIII defects in copper . I »The analysis mentioned here shows that the ability of thermal migration of thedefects responsible to the stage III of the alloy is nearly the same as that of the stage
III defects in pure copper, in spite of an apparent discrepancy between the stage
temperatures of the alloy and the pure copper.
(2)

Stage I annealing

The annealing characteristics of the alloy between liquid helium and liquid
nitrogen temperatures were found to be different greatly from those of pure copper.
Isochronal annealing curves of them are shown in Fig. 2.
A notable difference between the alloy and copper appears as the reverse
annealing below SOK in the heavily irradiated alloy. An extent of reverse annealing is,however, almos t cancelled by the following normal annealing up to liquid nitrogentemperature, so that the total amount of recovery between these temperatures is almost
independent of the irradiation dose. It is obviously the result of this cancelling effectthat the damage introduction rate at liquid helium temperature is larger by only about
30 %than that at liquid nitrogen temperature, as was reported previously.3)
At present it is difficult to determine which of the reverse and normal annealingstages of the alloy corresponds to the defect migration occurring in the stage I of purecopper. Moreover, the fine structures of the annealing curve of the alloy bring aboutfurther difficulty in the interpretation of the stage.

124

Cu

E

<.J

G

-...;

0

a...
<l

.c
":;
en

T

L

10

"0

1

§
Q)

-8

~
0

Q)

D.·cm

C

c

<!

0
-7
t.Pi (10 n'cm)

o

0

1.59

(){-17MeV+

1.01<:X-17•0.50

p- 3.5

10

20

30

40

50

60

70

80

90

100

Annealing temperature T fK)

Fig. 2. Stage I annealing of CU3Au
and Cu irradiated with alphaparticles or protons at liquid
helium temperature.
Annealing time at eachtempera ture is 5 min. (jIJi
is a total increase ofresistivity by the irradiation.)

References
1)
2)
3)

H. Sakairi, E. Vagi, T. Karasawa, and R.R. Hasiguti: IPCR Cyclotron Progr. Rep.,i., 140 (1970).
W. Schilling, G. Burger, K. Isebeck, and H. Wenzl: Vacancies and Interstitials in
Metals, (ed. A. Seeger et al.) North-Holland, Amsterdam, p. 255 (1970).
H. Sakairi, E. Vagi, A. Koyama, T. Karasawa, and R.R. Hasiguti: IPCR Cyclotron
Progr. Rep., ~, 101 (1971).

125

9-3.

Electron Microscopic Observation on Helium Bubbles in Aluminum
Irrad iatedby A Ipha- Partie les

H. Sakairi, E. Yagi, H. Shiraishi,
T. Karasawa, and R.R. Hasiguti

Helium bubbles generated in pure aluminum irradiated by alpha particles havebeen observed by transmission electron microscopy. The aim is to investigate therelation between the bubbles and various lattice imperfections.
Examples of bubbles generated on dislocations or at grain boundaries wereobserved and already reported .1),2) It is certain that helium atoms precipitate
preferentially on such imperfections. It was, however, s ugges ted that the interaction
between bubbles and dislocations is rather weak so that the dislocations can be released
easily from the trapping by bubbles during thermal annealing.
Subsequently an example of the bubble-boundary interaction was observed in a
specimen which was deformed after injection of He. As shown in Fig. 1, a grainboundary migrating for recrystallization is bent by pinning action of bubbles. The
calculation by Speight and Greenwood 3 ) predicted that small bubbles are swept up by the
migrating boundary while large bubbles are left behind it. Condition of the bubble
sweeping was determined in terms of radius of bubbles and distance between them as
illustrated in Fig. 2. However, a free energy difference Ll F between atoms in adjacentgrains was left as an undetermined parameter, which can vary greatly in magnitude by
the circumstances. It is therefore uncertain whether the bubbles of such size as inFig. 1 can still be swept up by the boundary or not. From the location of theexperi mental poi nts in Fig. 2, which is regarded as of the bubbles left behind themigrating grain, LlF is estimated to be larger than 10 - 16 erg/atom in our specimens.

Fig. 1. Grain boundary bent by bubbles. (Observedin an annealed specimen for 1.5 h at 645 0 C,
after deformation of 8 % tensile strai nfollowing 87 ppm He injection.)

126

uu
uu
0
0
0

o

163

E

00 00
00 00
~ <0 rt) <0t-Bubbles left behind,\1 e~~1
c>Y~\O

2

~\O~

co

CD

:a
.D

:::J
..0

c:

CD
CD
~

10- 4

Q)
..0

CD

0

g
.S!

co

0

1(55

Bubbles swept

10 6

10 5

10

4

Radius of bubbles (em)Fig. 2. Illustration of sweeping condition for
bubbles calculated following Speight et
a1. 3 ) The bubbles on the upper side of
the curve cannot follow the migration of
the grain boundaries. (Experimental
pOints were obtained by the authors 2)
for speci mens annealed at 600 °C; J ,injected with 43 ppm He, x , injectedwith 43 ppm He and deformed to 8 %tensile strain, 0, injected with 87 ppm
He .)The radius of bubbles in question is 2 x 10- 6 cm and the distance between them is 10- 4cm, so that they seem to locate in the region where they cannot follow the migratingboundary.

References
1)
2)

3)

R.R. Hasiguti, E. Yagi, H. Sakairi, M. Kobayashi, and T. Karasawa: IPCR
Cyclotron Progr. Rep., !, 144 (1970).
H. Sakairi, E. Yagi, H. Shiraishi, T. Karasawa, and R.R. Hasiguti: ibid., ~ 98
(1971).
M.V . Speight and G.W. Greenwood: Phil. Mag., ~, 683 (1964) .

127

10. RADIOISOTOPE PRODUCTION AND ITS APPLICATIONS

10 -1.

Production of Radioisotopes for Medical Use

T. Nozaki, T. Karasawa, M. Okano, A. Shimamura,
M. Iwamoto, T. Ido, and Y. Makide

Efforts have been made to increase the production yield for 18F and 43K, toprepare some 18F-labelled organic compounds for injection into experimental animals,
and to find a convenient process for the production of 197mHg. Also, the facility forthe inner bombardment has been improved.

(Window holder)(Cool ing part)(Moi n port)

Fig. 1. Target assembly for the 3 He bombardment ofwater.
200

/'1\

I \

~
o

50

L

U

o

/
/

\ "'

I'-----

5
Deuteron

10
Energy15

20( MeV)

Fig. 2. Excitation curve for the Ne + d ---+ 18F reaction.

128

Figure 1 shows the target assembly for the production of carrier-free 18F by the
3He bombardment of water. The vessel is made entirely of titanium. Practic:rlly,
about 60 mCi of 18p ready for intravenous injection can be obtai ned routinely by thisbombardment. The excitation curve for the Ne +d -- 18p reaction has been measured;
it is shown in Fig. 2. We are, however, not as yet entirely sure in the shape of thecurve in Pig. 2, and are continuing the measurement. The experimental results so
far obtained suggest the presence of some fine structures in the deuteron energies of 8
to 10 MeV . It is now clear, regardless of the fine structures, that the thick target yieldof 18F is larger for the Ne + d reaction than for the 0 + 3He reaction by a factor of about
1.5 for an equal beam current.
18p -labelled p-fluorobenzoic acid and cholesteryl fluoride were prepared 1) andinjected into mice or rats, and the resultant distribution of the 18F was measured. The
results are shown in Figs. 3 and 4.
By the a -particle bombardment of an argon stream, 43 K has been produced. It
has been found that more than 90 %of the 43K formed in the stream is adsorbed withina glass bombardment vessel (about 1 m length, 6 cm diameter), when the streaming rate

1000

1000

500

(l)

>

=:i

0'

-+-'
~

c::

0

:J

I

--.J

c::
4>
(l)

c.

II>

4>

II>

~

<J)

~

(l)

t-

(l)

c::
0

([J

o

Fig. 3. Distribution of p-fluorobenzoic
acid.
10

10

.--~------------- Blood(%/ml)~-=--=:::\:1) Liver
Adr enal- '- -~----------l~~ Spleen
Lung-/-".......--===----===------411. Kidneyc::o------~H Heart__~_e.C!fJ. _'{C! Lu_e. ____ __ ____ _____ ___ _________ _-® Bone0.1

0.1

0.0 '0!-----'--1----l.-~2----'-----;:;
3---'---4:!-----' 0.0 I
Ti me

after intra venous injection( h)Fig. 4. Distribution of cholesteryl fluoride
and its change wi th time.

129

is about 2 f /min. The adsorbed 43K has been shown to be eluted efficiently by thecondensation of steam on the inside wall of the bombardment vessel. Thus, 43K readyfor intravenous injection is prepared with a yield of about 2 mCi/hr.
The excitation curve for the 197Au(d,2n) 197mHg reaction was roughly measured,and the separation of the 197mHg from the gold target was studied. For a 20 MeV
deuteron beam, about 0.6 mCi of 197mHg has been shown to be formed per ttA -hr,accompanied with a much smaller activity of 197Hg. No noticeable loss of the productmercury from the gold target in the course of the bombardment has been found, andthe separation yield of the radiomercury has proved to be over 90 % in our method.

Reference
1)

T. Nozaki, A. Shimamura, and T. Karasawa: IPCR Cyclotron Progr. Rep., ~, 156(1968).

130

11.

RADIATION MONITORING

11-1.

Routine Monitoring

K. Koda, I. Sakamoto, and I. Us uba

The results of routine monitoring on the IPCR cyclotron obtained from April 1971
to March 1972 are described.
1)

Res id ual activities of the machine

Dose rates at the acceleration chamber were 100 mR/h on its outer surface and
5 R/h at the septum, 20 h after machine shutdown. An order of several mR/h wasobserved at the Q magnets of each beam course.
2)

Leakage radiations

Measurements of leakage radiation were made using gamma -ray film badges andneutron pocket dosimeters at various points around the cyclotron room under thecondition that a 147S m2 0 3 target was bombarded by 9"-' 10 /J,A 3He beam of 38 MeV.
A mong the res ults obtained, it is worth mentioning that the dose rate in the vicinity ofloop holes in the large experimental area was 3 mrem/day (gamma +neutron) and thatat the entrance to the cyclotron room from the underground passage was 50 mrem/day
where the contribution of gamma rays and neutron was 30 and 20 mrem/day,
respectively.
3)

Floor and air contamination

The surface contamination on the floor of the cyclotron room was kept about 10- 5/lCi/cm 2 si~ce the preceding period. Those of the experimental areas, hot laboratory,
and chemical laboratories were of the order of 10- 7 f.LCi/cm 2 . On the inner surface of
the acceleration chamber the contamination of 2 x 10-2 /lCi/cm 2 of tritium and 10-5
/lCi/ cm 2 of other beta - and gamma -emitters was found . .
The tritium still remained in the acceleration chamber since the last triton
acceleration in December 1970. About 10- 2 /lCi/cm 3 of tritium concentration was
found in the air within the chamber, and 8.4 mCi of tritium was recovered from the air
by purging the chamber with fresh air and trapping the moisture in a water bubbler.
The tritium contamination of air in the cyclotron room ranged from 10- 5 to 10- 6/lCi/cm 3 .
4)Personnel monitoring

The values of accumulated dose of external exposure during the present period of
all cyclotron workers issued with the gamma -neutron film badge are shown in Table 1.
The average annual dose per person was 261 mrem and is decreasing year by year.
The main reason is the reduction of work time for high -level operations such as septum
replacement.
About 60 mrem of thermal neutron exposure was observed for the first time since
the start of cyclotron operation. The internal exposure of the workers to tritium was

131

reduced to almost zero by purging the air in the acceleration chamber completely
before overhauling.
Table 1.

Accumulated dose distribution of the cyclotron workers
from April 1971 to March 1972.

Dose (mrem)

Undetectable

Operators

101------300

301"-' 1000

3

4

Nuclear physicists

6

8

4

Accelerator physicists

1

3

2

Physicists of other fields

15Radiochemists

1

2

Radiation chemists

2

Biological chemists

2

Heal th phys icis ts

1

1

Average annual dose per person
261 mrem.
Maximum annual dose: 1360 mrem.

1
1

1> 1000

1

132

12.

LIST OF PUBLICATIONS

T. Nomura and T. Yamazaki: "Effective Magnetic Moment and E2 Polarization
Charge in f7/2 Nuclei", 'The Structure of the 1f7/2 Nuclei t ed. R. A. Ricci(Editrice Compositori, Bologna, 1971) p. 437.
2)

T. Nomura, T. Yamazaki, S. Nagamiya, and T. Katou: "Magnetic Moment of theLowest 6+ State in 42Ca", J. Phys. Soc. Japan, 33, 286 (1972).
T. Nomura, K. Hiruta, T. Inamura, and M. Odera: "In-Beam Alpha Spectroscopy
of N=128 Isotones, Lifetimes of 216 Ra and a New Isotope 217 Ac", Phys. Lett., 40B,
543 (1972).
-

/

/

4)

J.r. Fujita, S. Yamaji, and M. Hirata: "Effects of Exchange Currents on Orbital
g-Factor and El Sum Rule", J. Phys. Soc. Japan., 33, 541 (1972).

5)

T. Kammuri, S. Kusuno, and S. Yamaji: "The Use of the Angular Momentum
Projection Technique in Two -Nucleon Transfer Reactions on Deformed Nuclei",
Phys. Lett., 39B, 327 (1972).

6)

Y. Awaya, K. Matsuda, T. Wada, N. Nakanishi, S. Takeda, and S. Yamaji:"Inelastic Scattering of Protons from 100Mo and 98Mo", J. Phys. Soc. Japan, 33,
881 (1972).

7}

Y. Abe and N. Takigawa: "Stability and Persistency of a Cluster Structures"
Prog. Theor. Phys. Suppl., ~ (1972).

oY. Miyazawa, 1. Kohno, T. Tonuma, T. Inoue, A. Shimamura, and S. Nakajima:"A Source for Multiply-charged Ions and Acceleration of C, Nand 0 Ions by IPCR
Cyclotron", IEEE Trans. Nucl. Sci. NS-19, 105 (1972).

r;

9}

I. Kohno, Y. Miyazawa, T. Tonuma, T. Inoue, A. Shimamura, and S. Nakaj ima:
"Production of Multiply -charged Ions of Ne, Ar, Kr and Xe by the Electronbombarded Hot Cathode Ion Source of IPCR", IEEE Trans. NucL Sci., NS-19, 109(1972).

10)

K. Mats uda: "On the Acce leration of Hea vy Ions in a Cyclotron", Sc i. Papers
I.P.C.R., 66, 33 (1972).

11)

M. Odera and T. Tonuma: "A Variable Frequency Linac for Acceleration of the
Low Energy Heavy Ions and its Use as a Prestripper Accelerator for a Separate
Sector Cyclotron", Proc. 6th Intern. Cyclotron Conf., Vancouver (1972).

12}

F. Ambe, H. Shoji, S. Ambe, M. Takeda, and N. Saito: "A Mossbauer Study of the
Valence State of 119S n after EC Decay of 119Sb in Antimony, Sb2Te3 and Sb2S3 ",Chern. Phys. Lett., lio 522 (1972).

133

13)

T. Nozaki, Y. Makide, Y. Yats urugi, Y. Endo, and N. Akiyama: "Chemical
Behavior of Carbon in High -purity Silicon in the Dissolution and Fusion of the
Matrix", Bull. Chern. Soc. Japan, 45,2776 (1972).

14)

Y. Endo, Y. Yats urugi, N. Akiyama, and T. Nozaki: "Infrared Spectrophotometry
for Carbon in Silicon as Calibrated by Charged Particle Acti vation", Anal. Chern.,
44,2258 (1972).

134

13.

LIST OF PERSONNEL

Members of the Board
MIYAZAKI Yukio g M;j 1{gfit (Chairman)
HAMADA Tatsuji ~ B3 ~IMAMURA Masashi A, ;ftl§=Cyclotron Users Committee=

HAMADA Tats uji ~ B3 ~(Chairman)
IMAMURA Masashi
A,;ftl§
KAMITSUBO Hiromichi 1:.:Pf 'it m
KARASA WA Takas hi
Mf iR.
4MA TSUYAMA Akira fl w ~KAMITSUBO Hiromichi 1:. :Pf 'it m
NAKANE Ryohei
r:p m .& .ljZ
ODERA Masatoshi IJ\ ~ IE ~NOZAKI Tadashi !f M;jIE
SAITO Nobufusa li Ifi 1§" m
SAKAIRI Hideo :!& A ~ fit
SEKIZA WA Hisashi M iR.
/PJManagers of Users Group
HAMADA Tatsuji
NOZAKI Tadashi

ODERA Masatoshi

IPeR Cyclotron Operating Personnel
Machine GroupHEMMI Masa take ~ 5i!, iI5I: lit
INOUE Toshihiko # 1:. ~ ~MIYAZAWA Yoshitoshi g iR. 1* ~SHlMAMURA Akira {11 ;ft
TONUMA Tadao pi 113 IE fit*

Operation
FUJITA Shin i.i B3m
IKEGAMI Kumio ttl! 1:.11 = 515
KAGEYAMA Tadashi ~ w
KOHARA Shigeo IJ\ ~ m 7<::.

IE

NAKAJIMA Hisao r:p ~~ /PJ fit~
TERAJlMA Osamu {f{11iW
OGIWARA Kiyoshi ~@Scientific and Engineering Personnel
Cyclotron Lab.
CHIBA Yoshiaki :r ~ B- ~FUJISA WA Takashi Ifi iR. ~ ;:0
FUJITA Jiro Ifi B3~~
HASHIMOTO Osamu #iii
tf:;
HEMMI Masa take ~ 5i!, iI5I: lit
HIRUTA Kotaro ~B3 $*~~INAMURA Takashi
fill ;ft~
INOUE Toshihiko # 1:. ~ ~KAMITSUBO Hiromichi 1:.:Pf 'it m
KARASAWA Takashi m iR.
4KOHNO Isao 1PJ!f~MIYAZA WA Yoshitoshi f5 iR. ft ~M OTONAGA Shos hichij[; ik lIE t
NAKAJIMA Shunj ir:p {11 W

=

'*

=

NAKANISHI Noriyoshi
r:p e§ ~ :g:
NOJIRI (INANAGA) Tamaki~ Jj1, ~ ~g
NOMURA Toru ~ ;ft~
ODERA Masatoshi IJ\ ~ IE ~SHIMAMURA Akira {11 ;ft
TAKEDA Shigeru t'r B3~
TAKIGAWA Noboru ~ )1\~
TONUMA Tadao pi 113 IE fit
TOYAMA Manabu n w $YAMAJI Shuhei
w ~ 1~ .ljZ
YAMAZAKI Yoshishige w dffjJ .& .5J(;
YOSHIDA Fusako 8 B3 m-rYOSHIE Morio 8 iI ~ 515
WADA Takeshi ;fa B3
fit

*

135

(Visitors)
EJIRI Hiroyas u IT JJL li:. ~ (Univ. of Osaka)
FUJINO Takeo Jfi!f JIt x(Inst. Nucl. Study, Univ . of Tokyo)
FUJITA Junichi Jfi EB *~(Tokyo Univ. of Educ.)
HANAZONO Sakae n ~(INS, Univ. of Tokyo)
IMANISHI Bunryu A, ~ )( 1i (Nihon Uni v.)
KOIKE Masahiro IJ\ @ 1£ li:. (INS, Uni v. of Tokyo)
LIN Ching Liang~ iR:(Univ. of Formosa)
MIKUMO Takashi~~(Tokyo Univ. of Educ .)MATTHIAS, E. (Freie Univ. Berlin, West Germany)
NAGAMIYA Shoj i ik '§ 1£ tEl (Dept. Phys .-, Univ. of Tokyo)
NAKAI Koji
~ it ¥~(Dept. Phys ., Uni v. of Tokyo)
OHNUMA Haji me *- 111
m (INS, Uni v. of Tokyo)
PINGEL, K. (Max-Planck-Inst. Fur Kernphysik Heidelberg, West Germany)
RECKNAGEL, E. (HAHN-MEITNER lnst. f. Kern Forschung GmbH li. Freie Univ
Berlin, West Germany)
SEKIGUCHl Masayuki ~ 0 ;fit IT (INS, Univ. of Tokyo)
YAMANE Isao W fN
:w (Res. Center Nucl. Sci. and Tech. Univ. of Tokyo)
YAMAZAKI Toshimitsu W Mii ~:J't (Dept. Phys., Univ. of Tokyo)
YAZAKI Koichi~ Mii 1ft (Dept. Phy s. Univ. of Tokyo)

-

*

**

=

=

Radiation Lab .
AWAYA Yohko W: ~ ~ T
HAMADA Tats uj i
~ EB ~HASHIZUME Akira #ii 11\
AA
KATOU Takeo 110 Jfi JIt ftl
KONNO Satoshi
~!f
iW

=

KUMAGAI Hide kaz u !i~ ~ ~ fa
OKANO Masaharu r5iJ!f ~ r#i
TAKAHASHI Tan ~ #ii
S
TENDOW Yoshihiko T.. 1m: =Jj ~(Visitors)
NAGAHARA Teruaki
71< @: Jffi ~ (Rikkyo Univ.)
ANDO Jun '!Zm (Kanazawa Univ.)
DOKE Tadayoshi
1m:,,&, ~(Waseda Univ .)SUZUKI Kazuaki ~ .(t;: - aJl (Japan Anal. Chern. Res. lnst.)**

Nuclear Analytical Chemistry Lab.
AMBE Fumitoshi '!Z $ )( ~AMBE Shizuko '!Z $ D T
ARATANI Michi m ~ ~ iW

MAKIDE Yoshihiro ~ t:I:l ~ 1ft
NOZAKI Tadashi ~ Mii
1£
SAITO Nobufusa 1f,i B 1§" m(Visitors)
AKIYAMA Nobuyuki f-* W 1§ Z
(Komatsu Electronic Metals Co., Ltd.)IDO Tatsuo it pi ~ ftl (Nat. Inst . of Radiological Sciences)
FUKUSHl Kiyoshi m ±~(Nat. Inst. of Radiological Sciences)
YATSURUGI Yoshifumi J\ ~IJ 'is)((Komatsu Electronic Metals Co., Ltd.)Radiobiology Lab.
IGARASHI Kazui E+it - EX.
KIT AJIMA Y oshio ~t ~~ ~ ~MATSUYAMA Akira fl w
YATAGAI Fumio ~EB~)(x136

Radiation Chemistry Lab.
IMAMURA Masashi A,:t.t
KIMURA Kazuie *:t.t - ?

B

MA TSUI Masao~ ~SHIOTANI Nobuhiro
YAGI Eiiehi J\

E3Metal Phys ies Lab.
HASIGUTI R. Ryukiti #iii 0
KOYAMA Akio IJ\ ill B13 1it
SAKAIRI Hideo ~ A !Jf 1it~ B- ]:I 51**-(Visitors)*

IS HINO Shio ri 1]!f(Uni v. of Tokyo)
MISHIMA Yoshitsugu -= 8!b ~ *l (Univ. of Tokyo)
SHIRAISHI Haruki B 1J ~ fM (Nat. Res. Inst. for Metals)
Magne~ie Materials

Lab.

OKADA Takuya Itlil 83 ¥ -tQ
OKAMOTO Shoiehi /illi~'* -S EKIZA WA Hisashi/}€I ~

Radiation Monitors
KODA Kugao Ej3 83 j)i :'J3
SAKAMOTO Iehiro ~'* -USUBA Isao

If. ~

~

Jj!fs

(Editors of the Progress Report)
AMBE Fumitoshi tJi. $ )( iIU.
B
E3
IMAMURA Masashi A, :t.t

ODERA Masatoshi /J\:$j: IE {~SAKAIRI Hideo ~ A !Jf 1it

~

137

14.

LIST OF OUTSIDE USERS AND THEIR THEMES

Description is in the order of theme, particle and energy used, users' name(s)institution, and number of times of use.
1)

2)

3)

4)

5)

6)

7)

8)

"Production of 43K for Heart Diagnos is".
a -29 MeV.
M. Nakamura et al.,Med. Dept., Kyushu Univ.

(5)"Production of 52Fe used for Diagnosis
3He-40 MeV.
Y. Murakami et al.,Tokyo Metropolitan Uni v.

(3 )

II.

"Production of 76Br for Study of Internal Conversion Electrons".
a-41 MeV.
T. Nagaha ra ,Rikkyo Univ.

(1)"Production of 18F for Tumor Search".
3He, 18 ",21 MeV.
H. Kakehi,
Chiba Univ. Hospital,
A. Ts uya ,National Cancer Center Res. lnst.,
H. Murayama,
Tokyo Medical Univ.

(8)"Production of 197Hg for Diagnosis of Lung Tumor".
d-22 MeV.
M. lio and T. Hara,
Nakano National Hospital.

(2)"Meas urement of Exci tation F unction of the Reaction 54Fe (a, n) 5 7Ni ".
a -25 MeV.
S. Tanaka,
lnst. Nucl. Study, Uni v. of Tokyo.

(1)"Production of 123 1".
3He -40 MeV, a -40 MeV.
O. Ezawa,
Chern. Dept., Tokyo Metropolitan Univ.

( 8)"Study of Effect of Helium Bubbles on the Mechanical Behavior of StainlessSteel, SUS 32".
a -32, 35, 36 MeV.
T. Katou, S. Kawasaki, and T. Furuta,
Japan Atomic Energy Res. lnst.

(7)

138

9)

"Simulation Study by Charged particles of Neutron Damage of Reactor
Mate rials" .
p-6, 10 MeV (2); a -23,34,35 MeV (5).
H. Kamei and M. Terasawa,Electrical and Nuclear Engineering Lab.,
Toshiba Research and Development Center.

10)"Production of 54Mn as a temperature Indicator at the Nuclear Alignment
Experi ment" .
p-I5 MeV.
K. Nagamine and H. Koyama,
Phys. Dept., Univ. of Tokyo.

(1)

11)

"Production of 2IOAt for Study of Hyperfine Interaction of the Isomeric Statesof 2IOPo".
a -42 MeV.
S. Nagamiya et al.,(1)
Phys. Dept., Univ. of Tokyo.

12)"Production of IIIIn for Tumor Search".
a -43 MeV.
H. Kakehi,
Chiba Univ. Hospital.

(3 )"Study of PotassiUl Metabolism by 43K".
a -29 MeV.
Y. Araki and M. Kashima,Med. Dept., Univ. of Tokyo.

(3 )"Study of Excited States of 76S e and 124 Te ".
a -43 MeV.
T. Nagahara,
Rikkyo Uni v.

(1)"Production Study of 53Mn".
d -9 .0, 10.0 MeV.
S. Umemoto and S. Shibata,Chem. Dept., Kyushu Univ.

(2)"Production of 7Be for Experimental Practice at the Highest Class of Radiois otope Schoo I" .
p-I4 MeV.
K. Noguchi et al.,Radio -isotope School,
Japan Atomic Energy Res. Inst.

(2)"Activation Analysis of Impurities in Silicon".
3He-20 MeV.
K. Noguchi et al.,Radio -isotope School,
Japan Atomic Energy Res. Inst.

(1)

13)

14)

15)

16)

17)

139

18)

19)

20)

21)

"Production of 55Co for Study of Nuclear Magnetic Resonance Phenomena of
Nuclei aligned at Liquid Helium Temperature"
p-17 MeV.
K. Nagamine,
Phys. Dept., Univ. of Tokyo.

(1)"Production of 52Fe".
3He-40 MeV.
O. Ezawa et al.,Radio -isotope School,
Japan Atomic Energy Res. lnst.

(1)"Production of 179mHf for study of E2-to-Ml Ratio in its Cascade Decay".
a -33 MeV.
H. Kawakami,
lnst. Nucl. Study., Uni v. of Tokyo.

(1)"Production of Tl Radio-isotopes for Medical Use".

a -43 MeV.
J. Ando,Med. Dept.,
22)

Kanazawa Univ.

(1)"Measurements of Reaction Cross Sections of 66Sn(a ,n), (a ,2n), and (a ,an)".

a -25 MeV.

23)

M. Furukawa,
Chern. Dept., Nagoya Uni v .

(1)"Study of 148S m ".
p-17 MeV.
Y. Gohno and Y. lriya,
Phys . Dept., Tokyo lnst. Tech.

(1)

141

AUTHOR INDEXAKIYAMA Nobuyuki

f;kw f~ 2 106'1l. $ :>c fiiJ.

AMBE Fumitoshi'1l. $ fft T

AMBE Shizuko

g T

~ Nl

FUJISA WA Takashi
fUJITA JiroJfi 83

FUJITA ShinJfi 8337,45

HARADA Kichinosuke=@ 83 2f 2M 49

KIMURA Kazuie* tt -KOHARA Shigeo

IJ\ @ £ ~HASHIZUME Akira

fI m

M 66,70

KOIKE Masahiro

HASIGUTI R. Ryukiti

fI 0

~ 2f

KOYAMA Akio

HIRUTA Kotaro
100 Tatsuo

~

%J!f

IJ\ w BBKUMAGAI Hidekazu¥ 83 ~ ~Machine Group!I!.t 83 ¥ *a~ 76,80:# .F :il:it 127.li

IKEGAMI Kumio;m L :tL =~

~ it

127

fl 83 - !A 37

MATSUDA Kazuhisa

fl it .iE ~ 108,110

MATSUI Masao

MATSUYAMA Akira

A, tt

~

INAMURA Takashi

flB tt-* 76,80

INANAGA Tamaki

ffB 7k ~~§30, 33, 45

MIKUMO Takashi

INOUE Toshihiko

it L fiiJ. ~5,7,96MIYAZAWA Yoshitoshi:!5::$: if -r 127*ft

n lYj 37

IMAMURA Masashi

IWAMOTO Masako

30,33,45m 122~ tfj ~

MAKIOE Yoshihiro

MA TTHIAS E.

20,23,27,89~~ B- ~ :fa 66,87

7,12
108,110

7

2MAS UI Kuniaki+ it -fX: 11 4

IGARASHI Kazui

108,110,114,119,
122,125,127

110

IJ\;m iE 'fR

J! iJj( ftt . 7,12,21,96
47

15,23,27,30,
33,45,89:I t ~~ ~ ~ 11 4
83 l i ~ 130

KOHNO Isao

HIRATA Michihiro~

Ej3

m 73,80,84

122,125

1f:.

J8?R

*J ttI2 ~flI!T 110

fI -*

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KIKUCHI Mariko

KOOA Kugao

70,87

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110 Jfi ftt m 66,70,87

HASHIMOTO Osamu

HEMMI Masatakew

KITAJIMA Yoshio

7~ 83 ~~KAGEYAMA Tadashi

KA TOU Take 0

70= a~ 47,92,96

HAMADA Tatsuji

87

KARASAWA Takashi

jJi ?R ;l§ij;=G; 12,30,33,~

ill ~ ]It -KAMITSUBO Hiromichi

102,104

m B- ~ ~ 99

ARATANI Michi
AWAYA Yohko

102,104

IZUMO Koichi

fl

w

~

114

84
~
--= -=MIZOGUCHI Tadashi

~

27,45

-g iR f* fiiJ.
~ 0

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119

7

142

MOTONAGA Shoshichij[; 7kfIB t

12,37,96

NAGAMIYA Shoji ik '8 if t#i 73,84
NAKAI Kozi

t:j:l

= 73,84#- ~NAKAJIMA Hisao

t:j:l ~~

NAKAJIMA Shunji

t:j:l ~ gf

NAKANISHI Noriyoshi

SUEKANE Shota*§

TABATA Yoneho

E8

m* l! 110

TAKAHASHI Tan

~ ~

*- 49

l§

1!

r6J fit 7,96

T AKEBE Hideki

fIt $ 3i:.;fM=

TAKEDA Shigeru'It EE

23,27,43,89

114

12
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t:j:l f!.§ *c. ~ 35,96

TAKIGAWA Noboru

~ )1\

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73,76,80

TENDOW Yoshihiko~

TERAJIMA Osamu~ ~35,43,92,96~ 58

NOMURA Toru

!f t-tNOZAKI Tadashi

If dffij

if 106,127

ODERA Masatoshi

Ij\

15,18,21,~ if ~ 23,27,43,
76,80,89

OGIWARA Kiyoshi

~ rnt

i'i1f

7

TOYAMA Hinako

7} w.1:t!¥iT 35

OHNUMA Hajime

*- tB

m 35

TOYAMA Manabu

7} IIIfW ~l1<~ EE .$: tI2 119

OKADA Takuya

OKANO Masaharu
OSHIMA Keichi
PINGEL, K.

~!f Ji t#i 87,127*- ~ :m -

110

7

7,18

~

53

130

WADA Takeshi;fD B3YAGI Eiichi*= * - 122,125

J\

YAMADA Satoshi

30~,F tB if fit

TONUMA Tadao

USUBA Iscto

ill 'Jj Ej66,70,87

fit

w EE

30,33,45tt

35

RECKNAGEL, E.

84

YAMAJI Shuhei

w ~ {~SJZ 37,47,49

SAITO Nobufusa

li Hi {~ m 102,104

YAMANE Isao

w m m 23,27,89

SAKAGUCHI Harutaka
SAKAIRI Hideot#i ~ 37

jjj 0

jjj A 3i:. fit 122,125*-

YAMAZAKI Toshimitsu

w dffij fili JIt 73,84

YAMAZAKI Yoshishige

w dffij ~ fft 73,84

B- EE ~)(~

~~

130

YA TAGAI F umio

00 R

!¥U

119

YATSURUGI Yoshifumi

SHIMAMURA Akira~*

5,7,127

YOSHIDA Fusako

SHIOTANI Nobuhiro

j][ B- 8 5J,.

119

YOSHIE ' Morio

SAKAMOTO Ichiro

jjj

SEKIZAWA Hisashi

SHIRAISHI Harukitt

B E ;If ~

125

114

J\ ~o 5)( 106

5 EE mT
5 IT ~ ~18,37

23 ,27 ,89

IPeR Cyclotron Progress Report
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理化学研究所
埼玉県

和光市

広沢