the Institute of Physical and Chemical Research
Wako-shi, Saitama Pref., JAPANIPCR cyclotron
Progress Report 1975

Vol. 9

IPeR Cyclotron Progress ReportVol. 9The Institute of Physical and Chemical Research"RIKAGAKU KENKYUSHO" Wako-shi, Saitama, 351 JAPAN
December, 1975

Editors
F. AmbeA. Hashizume

M. Imamura

T. Inamura

M. Ishihara

H. Kamitsubo

H. Sekizawa

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

CONTENTS
Page

1.

INTRODUCTION

2.

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

3.

MACHINE DEVELOPMENT AND ACCELERATOR PHYSICS

4.

...................................................................................... ................. .
2

3-1.

Polarized Ion Source for the INS Cyclotron ..... .............................................

4

3-2.

Improvement of the Central Region Geometry in the Cyclotron ..................

6

3-3.

Improvement of Power Supply for the Beam Handling System

8

NUCLEAR PHYSICS
Scattering and Reactions
4-1.

Critical Angular Momentum in 12C + 14N Compound Reaction ....................

10

4-2.

Multiplicity of 'Y-Rays in Multi-Nucleon Transfer Reactions ..........................

13

4-3.

Fusion Cross Section Measurement by Beam Attenuation Method ...............

15

4-4.

Statistical Analysis of Multinucleon Transfer Reactions by Heavy Ions ........

17

4-5.

Anomalous Angular Distribution in the Transition to the2S 1/2 State in 17 0 and 13N .............................................................................

19

4-6.

The ct 4N, 13C) Reactions on sOTi, S2Cr, and s4Fe .. .......................................

22

4- 7.

Two-Step DWBA Treatment of Heavy Ion Transfer Reactions ......... .............

24

4-8.

Exact Finite-Range DWBA Calculations for the Reaction
60Ni ( 18 0, 160)62Nig.s. ......................................................................................

26

Analysis of Elastic Scattering of 16 0 by 19F (2)..........................................

29

4-10. Multi-Step Core-Exchange Analysis of 16 0 + 18 0 Scattering by
Full-Recoil Calculation .....................................................................................

32

4-11. The Multi-Step Effects of 17 0 ct 6 0, 16 0) 17 0* (1/2+)
Inelastic Core-Exchange Scattering ......................................... .........................

35

4-12. D(a,pa)n Reaction at Ea = 18 MeV.............................................................

38

4-13. 24Mg(d, p) and 26Mg(d, p) Reactions at Ed = 21 MeV.................................

41

4-14. Proton-Unbound States Excited by CreHe, d) Mn Reactions .......................

44

4-9.

Page

5.

4- 15. Analysis of Elastic Scattering of 3He on 13C ...............................................

46

4-16. Effect of CHe, a) (a, 3He) Two-Step Process in Elastic
Scattering of 3He on 13C ..............................................................................

49

4-17. Alpha-Gamma Angular Correlation Measurement forthe 13CCHe, a'Y) 12C(4.43 MeV) Reaction ..................................................

51

NUCLEAR PHYSICS
Nuclear Spectroscopy
5- 1.

6.

Gamma-Gamma Coincidence Study of the 92Mo and
94Mo + C Reactions ..................................... ..................................................

54

5-2.

Cross Sections for 88my and 90mNb via 89y + a Reaction (2) ....................

56

5- 3.

The Decay of 119m Te .....................................................................................

59

NUCLEAR INSTRUMENTATION
6-1.

,6-Ray Source Mounting onto a Foil Electrode in a Xenon Gas
Chamber ..........................................................................................................

62

Elimination of Unnecessary Peaks by Recoil
Coincidence Technique .. .... ... ........ .... .... ........ ... ..... ..... ... ... ............ ..... ... ..... ......

65

Position Sensitive Multiwire Proportional Counter
with Rear Helical Cathode Wire .. .... .... .................................. .... ... ... .... ..........

67

On a Simple Raw Data Acquisition System with a
Magnetic Tape Recorder .... ...... .... ... ..... ........ ........ .... ................ ... .... .... ... ........

70

6-5.

Upgrading of OKIT AC-45 OOC ...... .... ...... ...... ........ ..... ....... ......... ....... ...... ........

71

6- 6.

Computation of Multiple Coulomb Excitation ... ... ..... ........................ .... ... ...

72

6- 7.

Performance of SEM (Space Environment Monitor) for
Protons and Alpha - Particles ..........................................................................

73

Model Magnet of a Separate Sector Cyclotron

75

6-2.

6-3.

6-4.

6-8.
7.

ATOMIC AND SOLID-STATE PHYSICS
7-1.

Ar-K X-Rays Induced by 66 MeV C-Ion Impact

76

7-2.

A Bragg Crystal Spectrometer .......................................................................

79

7 -3.

Channeling Experiments with High Energy a-Particles

82............................ ....

Page

8.

7 -4.

Positron Annihilation in Aluminum .................. ...................... .......................

85

7 -5.

Mossbauer Effect of 61 Ni in Various Magnetic Oxides
and Sulfides ... ............ ........ ........ ....... .... ..... ....... ... ............... .. ............................

87

RADIOCHEMISTRY AND NUCLEAR CHEMISTRY

8-1.

9.

9-1.

Heavy-Ion Radiolysis of Liquid Isobutyraldehyde ...... ........ .......... .................

91

9-2.

Emission Spectra of Alkali Halides under Heavy-Ion
Irradiation at 4.2 K ................... ......... ........................ ...................................

93

Inactivation of Bacterial Cells with Different DNA
Repair Capacity by He-, C-, and N-Ions .......................................................

95

Effects of Heavy Ion on the DNA Synthesis in
Bacterial Cells .. ... .......... ... .... ........ .... .... ... ................ ..... .............. ... ..................

98

9-4.

PREPARATION OF RADIOISOTOPES AND LABELED COMPOUNDS

10-1. Production of Radioisotopes and Preparation of Labeled
Compounds for Medical Use .........................................................................
11.

12.

89

RADIATION CHEMISTRY AND RADIATION BIOLOGY

9-3.

10.

Mossbauer Emission Studies of Defect Atoms in Solid
after Nuclear Decay and Reaction ..................................................................

101

RADIATION MONITORING

11 - 1. Gamma-Ray Exposure from the Cyclotron Operation
at a Monitoring Station .. ...............................................................................

103

11 - 2. Routine Monitoring.........................................................................................

105

11-3. Neutron Measurement in the Cyclotron Room andthe Experimental Area ....................................................................................

107

11-4. Measurement of Residual Tritium ............................... ................ ...................

108

HEAVY ION LINEAR ACCELERATOR PROJECT

12-1. Status of Constructional Work of the Linear Accelerator
in December, 1975 ..........................................................................................

110

12- 2. Status of the Injector System ..... ............. ............. ..................................... .....

111

12-3. Structure of the Drift-Tube Magnet ...... ................ ......... ........ ............ ............

113

Page
12-4. Beam Acceptance of the Drift Tube Focusing System115

12-5. Effect of Misalignment of Focusing Elements
on Beam Acceptance ....................... .......................... .... ...................... ...........

117

12-6. Precise Measurement of the Symmetry Axis of Quadrupole
Magnetic Field . .... ... ............. ........ ................. ............... .... ...............................

118

13.

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

120

14.

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

125

15.

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

128

AUTHOR INDEX

129......................................................................................................

1.

INTRODUCTION

The operation of our cyclotron was satisfactorily smooth as before in last year. Several
improvements have been made in the machine and its accessory facilities.
A number of experimental studies of nuclear reactions and level structures was continued
from previous years. An on-line Bragg crystal spectrometer was installed to study heavy-ion
excited X-rays with high energy resolution. Channeling experiments were commenced withhigh energy alpha particles. Mossbauer studies were made on magnetic oxides and sulfides
and also on defective atoms in solid produced by nuclear reactions. Emission spectra of alkali
halides were measured under low temperature heavy-ion irradiation to obtain information on
initial species produced. Effects of heavy ions on the DNA synthesis in bacterial cells havebeen investigated, together with the production of radioisotopes and labeled compounds for the
medical use.
The first resonator of the heavy-ion linear accelerator is under construction and scheduled
to be installed next autumn. The foundation work for the accelerator building will bestarted at the end of this year and the building is expected to be completed in early autumn
next year.

Hitosi Hagihara, Chairman
The Cyclotron Board

2

2. MACHINE OPERA TION
K. Ogiwara, S. Fujita, H. Nakajima, K. Ikegami
T. Kageyama, S. Kohara, H. Takebe, and 1. Kohno

The cyclotron was operated on the 24h-per-day basis during the period from Oct. 23 1974
to Oct. 22, 1975.

Statistics of machine operation time is shown in Table 1.

time of 3853h is lower by about 12 % (520h) compared with last year.

The total working

This decrease in working

time is due to the increase of holidays and of the maintenance days of accelerator.
Table 2 shows beam time allotted to various activities in this period.

The cyclotron was

operated for 124 days with heavy ions because of increasing request for those ions.
11 B 3 +ions were accelerated at 70 MeV for 2 days.

In addition,

Total percentage of the request for heavy

ions exceeded 50 % and the machine time for solid state physics increased more than twice.
Serious troubles occurred in this period as follows.

The insulation of loading lines ofcircular trimming coils was broken by R-F leakage, and the circuits of those coils were shorted.
An induction motor of the circulation pump for deionized cooling water was also broken.
These troubles brought about a loss of time of about a month.
Facilities for magnet power supply to the beam handling system were moved to an
air-conditioned room to prevent hazard due to dust.
Table 1.

Machine operation.

Date

Oscillator

Ion source

BeamOct. 23, 1974

37715 (h)40591 (h)11025(h)Oct. 22, 1975

42088.3 (h)45174.3 (h)14878.2 (h)365 days4373 (h)4583 (h)3853 (h)

50 %

52%

44 %

Percentage of 365 days
Schedule in this period
Beam time242 (days)

Overhaul and installation work

46 (days)

Periodical inspection and repair

28 (days)

Vacation and holidays

49 (days)3

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

Table 2.

Heavy ionLight
particles

Total

1980 (h)826 (h)2806 (h)312142454 (h)RI production

0

312

312 (h)Nuclear chemistry0334

334 (h)Radiation chemistry

155

22

177 (h)Radiation biology

204

66

270 (h)Solid state physics

0463

463 (h)Inner atomic shell
excitation study48

15

63 (h)

Nuclear medicine
Nuclear fuel study

0

102

102

0

156

156

RI production

0

43

43

7

10

17

Total

2706 (h)2491 (h)5197 (h)Percent in total

52.1 (%)

47.9 (%)

100 (%)

Subject[ Nuclear reaction
In-beam spectroscopy

Nucl. phys.

Fields otherthan n ucl. phys.

Outside usersI

Development of instruments

Maintenance operation and engineering
Exchange of ion sources

68 (h)

Reserved for beam time adjustment
and cooling of radiation

435 (h)Machine inspection and repair

672 (h)Total1175 (h)4

3. MACHINE DEVELOPMENT AND ACCELERATOR PHYSICS

3-1.

Polarized Ion Source for the INS eyc lotron

S. Motonaga, T. Fujisawa, M. Hemmi, and I. Takeshita

The IPCR polarized ion source of a ground-state atomic beam type was successfully operated
Dissociater(wat
cooled)Oil diffusion(2500 I / s ). 2

iffusion

2400 I/s

Sextupole magnet
Oil diffusion pumj>(2000I/s)·2.

Focus Iunit
Ion pump(500 1/ s)

Ben ingmagnetFig. 1.

Schema tic view of thepolarized ion source for
INS cyclotron.

5

in 1974.1) Since that time, a number of components of the ion source have been rebuilt for
installation"in the S-F cyclotron of the Institute for Nuclear Study of Tokyo University.
In order to increase the ion beam intensity and the polarization value, several modifications
were made in chamber design, power supply and vacuum system to make dissociation at highpressure of 2 Torr. The ionizer was provided with 20 kV positive potential to the ground.
A particular attention was paid to achieve high vacuum in the ionization vacuum chamber.
A schematic view of the polarized ion source is shown in Fig. 1, illustrating the major componentsof the ion source.
The apparatus is now being in test operation and is to be installed in the cyclotron in thespring of 1976.

Reference
1)

S. Motonaga, T. Fujisawa, M. Hemmi, H. Takebe, K. Ikegami, and Y. Yamazaki: IPCR
Cyclotron Progr. Rep.,~ 84 (1974); S. Motonaga and T. Fujisawa: Proc. 4th Int.
Symp. Polarization Phenomena, Zurich, D - 1 (1975)

6

3-2.

Improvement of the Central Region Geometry in the Cyclotron

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

Figure 1 shows the performance record of last year.

Requirements of heavy ion beam havebeen increasing year by year, and the cyclotron was operated for about 2700 h with heavy ion
source in last year. There was a difficulty to keep the dee voltage stable in the heavy ion
In August, 1975, the central region was modified as shown in Fig. 2, to increase

accelerations.

the transit angle of the first half turn in the west dee so that vertical electrical focusing force
becomes to add to that of the magnetic field.

The west wing was extended along the path of
It was conjectured that thisions and the east wing was shaped flat as shown in the figure.

instability came from the following reason: a part of the first turn beam run into the east wing
because the axial magnetic focusing force is weaker than the electric defocusing force at thecentral region.

Many electrons were emitted from the east wing by collision of these ions.

These electrons were accelerated by r-f field along the line of magnetic field and bombarded thestems of the ion source. This collision eroded the ion source stems.

C2>f

>-

~
~

.'

,

• P
x 3He++
o

0

r;1

4He++

III

III

!"f

~

$

1m '"

¢

III
!2111

,:J'/fdt.

~ ~1i1/fl

Moreover, spark discharge

WJ3,p
%

III

{3

4r

"lo

~

!"fill

IZI

III

III

'"

'"

I

+ ~--+--_+_--+--+----+--__+_--j_____-_+-______i
501------------1 {3" 1°8
12 C4+
!
3

I

ill

0

Q)

r;1 14

u

u...

0

k?

t'

. "'<f

'"

i-I-

.

"

't

.
. .

-

o

d'

0

xx

0
00

b

0

x

..

.,.

'o

Pox

N4+

I

.

0<& ~ 0

I

1

0
P
SP
Trouble of circuler
p
p
~,t
-,'+
t r~
"
In COI'I S
j.
I~60~--~~-~Ei~-~-C=~--,~-,---,--,.--,-~. ~------,. . . .'"

..

,

_L

i

. ~50 ~--~-------1 j~;·-+---4-~4r-~-~-r~~v---+--~~~-~
'"
T
0
U

~ 40
g 30

••• ~

e

-, ~
b '0

"'.

g, g,

(b)

~ 20 p

1ZI

~~

'"

0

I

8

110

0

'"

Ox

E~ I

x

0

Q)

0
~

';§I

JZI

0

~c: ~0 I

~~

0

Q)

x

~ eI

0

w w

+'

.~

'"

.0

~

,.

I
I

I

I

I

Vacation overhau I
I

10 ::

~.

J : '" "8

Fig. I

Operation record of the cyclotron.

9

10

Arrows represent the repairof septum entrance and puller.
(a)Particle energies used.

(b)

Beam ex traction efficiency.

(c)Extracted beam currents were actually employed in experiments.

7

occurred at the central region between the dee and earth plate. To maintain same effective energy
gain for the first tum beam, the distance between the west and east wings was not changed.
Erosion of the ion source stems is now decreasing.

Other effects of this improvement willappear in the near future.

(J)

o ·

~

[

(1)

(")

3

Fig. 2.

Schematic drawing of the
improved central region

Cross-section (A-A')

geometry.

8

3-3.

Improvement of Power Supply for the Beam
Handling System

H. Nakajima, S. Kohara, and K. Ikegami

The beam handling system of the cyclotron consists of four analyzing and/or deflecting
magnets and fifteen pairs of quadrupole magnets. In order to combine suitably the ten pairs ofstabilized power supplies with the fifteen pairs of quadrupole magnets we prepared a power
supply distributor, the design of which was reported previously.l) This year we have installed the
distributor in an air-conditioned room to prevent the distributor from dust. Figures 1 and 2
show the front view of the handling board for the distributor and its main body. We have also
moved all power supplies for beam handling magnets from the power supply room to the
air-conditioned room mentioned above.
Following improvements of power supply have been made when it was brought into
in stalla ti 0 n.

For power supply of quadrupole magnets, phase control circuits of SCR (silicon control1ed
rectifier) were improved and the voltage of interlock system of cooling water was lowered from200 V to 12 V. For power supply of the deflecting magnets except SW II (see Ref. 1), a
main control system was replaced by a new circuit system which consisted of large -sizedtransistors and operational amplifiers. Figure 3 shows the new rack-mounted control system.

Fig. 1. The handling board for the power
supply distributor of quadrupole
magnets.

Fig. 2. The main body of power supply
distributor of quadrupole magnets.

9

Fig. 3. The new rack-mounted control system.

, '. ).".' ·;,1

• ••Fig. 4. The controller of power supply

II

Fig. 5.' The auxiliary controller of power

for a quadrupole magnet.

supply for a quadrupole magnet.

(installed in the control room)(installed in the power supply
room)

All control cables for magnet power supply were replaced with new cables.
Among the stabilized power supplies of quadrupole magnets, three pairs were replaced withthose of Hewlett Packard 62 - 74B type and for the DS magnet two series-connected power
supplies of Hewlett Packard 62 - 69B type were prepared to obtain stabilized small or medium
current. New controllers were attached to these new power supplies. Figures 4 and 5 arephotographs of these controllers.

Reference

1)

H. Nakajima and M. Hemmi: IPCR Cyclotron Progr. Rep., ~ 19 (1971).

10

4. NUCLEAR PHYSICS
Scattering and Reactions

4-1.

Critical Angular ,\I\omentum In 12C + 14N Compound Reaction

T. Ooi, T. Motobayashi, I. Kohno, M. Ishihara,
T. Numao, T. Fukuda, and S. M. Lee
According to the studies of 12Ce4N,6Li)20Ne reaction of Saclay group!) and Oxford group,2)
the compound nucleus formation is the main process in this reaction at energies between 20 and
76 MeV, and the critical angular momenta (fcr) in the compound formation have been derived
from Hauser-Feshbach (HF) analysis of individual level cross sections in the relevant outgoingchannel.

According to the studies referred to above, it was revealed that at a large incident

energy, the fcr value was less than the grazing angular momentum, fgr, which is defined as theangular momentum for which the transmission coefficient is 0.5.
In order to see the behavior of Pcr at higher incident energies, we have studied the 12 C+ 14 N
reaction at 70, 80, and 90 MeV. The data were compared with the HF calculation to extract
the values of P cr .
The experiment was performed with 14N4+ beams from the cyclotron.

The target was of

12 C self-supported foil of about 100 }1gj cm 2 in thickness.
Figure 1 shows typical energy spectrum for the 12 Ce 4 N, 6Li)20 Ne reaction.
ing to excited levels of 2°Ne are seen evidently.

Peaks correspond-

The energy resolution was 350-500 keV at

FWHM.
I

q-

+

12C(14N. 6Li )2<>Ne

w

q-

~

70 MeV

Fig. 1.

e

6Li energy spectra from the 12C 4 N,
6Li) 20 Ne reactions at incident energies
of 70, 80, and 90 MeV and 14.7 in
100

200

300

Ch anne l

the laboratory system.

Excitation functions for some 2°Ne levels measured at 14.7° and 10.4° are presented inFig. 2.

Solid curves indicate the HF calculation with fcr values which were chosen to give thebest fit to the experimental data.
.fcr+ I h

The Pcr values are listed in Table 1.

Dashed curves are with

Open circles show data of Saclay group and closed ones are ours.

are data of Oxford group at 76 MeV.

The triangular points

From the present analysis we obtained the .f cr values of17, 18, and 19h at Elab = 70, 80, and 90 MeV, respectively.

These fcr values are smaller than

11

fgr and fcr values obtained

Table 1.

from experimental data.
f cr(h)Incident energy (MeV)

fgr(h)

20
25

7
9

30
35

11
13

(11)

40

14

12

45

15

13

50
52

17
17
18

14
14
15

19
21
22
23

16
17
18'

55
60
70
80
90

12

19

12C (14N • 6 Li ) 20Ne

elOb~ 10.40

r-.-~~~~~~~

(a)
( b)

-

~

", \

t:

........
.0

3-

~b

5.63+5.80
31-

~

-

It
~

,,

r~ \

~

~

........

.0

1.63
2+

.3

~
~
~

1

'\

7.04+717+7. 2 \4T 0+ :\

'+,

\

20
flab. (MeV)

Fig. 2.

40

60

80

100

100
flab .

(MeV)

Excitation functions for some 20Ne states measured at 14.7° and 10.4° in thelaboratory system for the 12C (14N, 6 Li) 20Ne reaction.

12

fgr by 3 or 4h

It can be seen that considerably good fits to the data for all the outgoing channels in the
12C

e N, 6Li) °Ne reaction are obtained. This is taken to be a proof of the dominance of the4

2compound process even at these high energies.
Fusion cross section afus versus l/ECM plot is shown in Fig. 3.

The fusion cross section for

14N+ 12 C system at each incident energy has been calculated from the fcr value obtained above.
Two straight lines are fitted to the data with the help of Glass and Mosel's formulation: 3)
afus = 1TR~r(l-Vcr/EcM)'

fcr<.egr ,for small energies: afus = 1TRB (l-VB/E cM ),Pcr=£gr.

for large energies:

ELob . (MeV)

.0

E
::>

b 500

0.05

(1)

CTfus

= 1fRtr( 1 - EVer ) :;:; : 1 barn
CM

Vcr= 0

0 .15

0.10

1/ Ec.m.

Rer= 5.64fm

rcr = \. 20:!:: 0.06 tm(MeV fl(2)

2( 1- ECM
VB)

CTfus=rrRB

Fig. 3.

Plot of fusion cross for

V8= 5.26 MeV

sections afus vs. l/EcM

rB=1.53tm

12C + 14N reactions.

The line (1) implies
fcr <f gr ,afus < atotal reaction,

and the line (2)fcr = fgr ,afus = atotal reaction
From the line (1) we obtained rcr = 1.20 ± 0.06 fm, in terms of which the critical distanceshould be expressed like Rcr = rcr (Al 13+A113 ).

This rcr value is greater than rcr = 1.00 ± 0.07

determined by Lefort et al. 4) from heavy ion reactions with larger mass systems.

References
1)

C. Volant, M. Conjeaud, S. Harar, S. M. Lee, A. Lepine, and E. F. Da Silveira : Nucl.
Phys., A238, 120 (1975).

2)

T. A. Belote, N. Anyas-Weiss, J. A. Becker, J. C. Cornell, P. S. Fischer, P. N. Hudson, A.
Menchaca-Rocha, A. D. Panagistou, and D. K. Scott: Phys. Rev. Lett., 304, 450 (1973).

3)

D. Glass and U. Mosel: Nucl. Phys., A237, 429 (1975).

4)

M. Lefort: Proc. Int. Conf. on Classical and Quantum Mechanical Aspects of Heavy Ion
Collisions, Heidelberg, p. 274 (1974).

13

4-2.

lv\ultiplic ity of y-Rays in lv\ulti-N uc leon
Transfer Reactions

T. Numao, M. Ishihara, T. Inamura, and T. Fukuda

It has been shown that the multiplicity of ,),-rays, which means an average number of emitted')'-rays in a reaction, gives a good measure of the angular momentum involved in the initial excitedstates~),2)

In the present article, this idea was applied to the multi-nucleon transfer reactions

induced by heavy ions to study the reaction mechanism through the measurement of transferredangular momentum to the residual nuclei.

The multiplicity of ,),-rays, M, was deduced from therelation IdIs = 1- (l_r2)M, where r2 is the efficiency of ,),-ray detector, Is yields of outgoingparticles in singles, and Ic those in coincidence with ')'-rays.
The detection system for particles was a counter telescope consisting of 30 J,Lm and 2000 J,Lm
Si detectors.

A 3" X 3" NaI counter with a 4.5 mm-thick Cu absorber was used for the ')'-raydetection and placed at 7 cm from the target. The average efficiency of this system was foundto be 2.1 % indicating an accuracy within 10 % in the energy region from 0.2 to 2 MeV.

In

the coincidence measurement, ,),-ray energy, particle identification, and particle energy signals wererecorded event-by-event on a disk or a magnetic tape using an on-line computer.

To correct

the chance coincidence events, the timing spectrum between ')'-rays and particles was observed
during the coincidence measurement.

Contributions from neutrons emitted in the reactions werealso observed by putting a 5 cm-thick Pb absorber between the target and the N aI detector andwere estimated to be less than 10%. To see the angular correlation effect of ')'-rays, we placed the
NaI counter at 30° and 90° in the reaction plane and at the position perpendicular to thereaction plane, and found that the effect was negligibly small if the detector was set at 90° in
the reaction plane.
The multiplicities of ,),-rays were measured in this way for various particles emitted in the
14N+96Mo and 14N+181Ta reactions.

Figure I shows the multiplicity M around the energy ofthe optimum Q-value versus the number of transferred nucleons, AA, observed in the 14N+96Mo
reaction at () = 30° and EN = 95 MeV. The dashed line corresponds to a simple relation
2M = LlL = LlA • Vin· R,3) where Vin is defined as Vin = V2 (Ein-Ec)/Min with the incident energy,
Ein, the Coulomb barrier, E c , and the incident mass, Min, and R is the sum of two nuclear
radii.

For small LlA the observed multiplicity is in good agreement with this prediction, but it

differs considerably from the one expected for large LlA.

Figure 2 shows the multiplicity

obtained from the 14N + 181 Ta reaction at () = 50° and EN = 95 MeV.
appears in this case, too.

A similar character

Such an attenuation of the multiplicity can be understood as follows:In case of large LlA, two or more particles are emitted simultaneously or successively, and theyalso take out large angular momenta.

14

I

/

I

I

15

I

15

I

/

I

e =50

I

/
/
/
/

Li

He

H

•

+

I

C/

f

I
I
/
/

e = 30

I

B)f{

+

/

Li

5

+!

c

0

+-'1
I

I

I

/

I

/

/

I

/

I

10

5

0~--------~5----------~10---.1A

Fig. 1.

HeI+ 96MaEN= 95 MeV

I

/

t-r+

o

I

He

14N

/

0

10

Br~~l ~

5/II

EN == 95 MeV

I

I

10

+ 181Ta

14N

I

Multiplicity of 'Y-rays vs. the number.1A

Fig. 2.

Multiplicity of 'Y-rays vs. theof transferred nucleons observed in

number of transferred nucleons

the 14N + 96Mo reaction.

observed in the 14N + 181Ta
reaction.

References
1)

P. O. Tjm, F. S. Stephens, R. M. Diamond, 1. de Boer, and W. E. Meyerhof: Phys. Rev.
Lett., 33, 593 (1974).

2)

G. B. Hagemann, R. Broda, B. Herskind, M. Ishihara, and S. Ogaza: Nucl. Phys., A245, 166(1975).

3)

D. M. Brink: Phys. Lett., 40B, 37 (1972).

15

4-3.

by Beam Attenuation ,\I\ethod

Fusion Cross Section ,\I\easurement

T. Fukuda, M. Ishihara, T. Inamura,T. Numao, and T. Nomura

In heavy-ion induced reactions, it is important to determine what amount of fraction of thetotal reaction cross section is attributed to the complete fusion cross section uCF, since thisinformation may be useful to understand the dynamical properties of reaction mechanism.
Although there have been accumulated data of 0CF, the accuracy of the results is rather poor.
Moreover, the systematic measurement of uCF is often limited for the conventional methods used
so far.

In this note, we report on a new apparatus of the 0CF measurement which has beendeveloped to overcome those defects mentioned above.
A schematic drawing of the set-up is shown in Fig. I.

The collimated beam of heavy ionsof reduced intensity (105 particles per sec) was introduced into the apparatus and further refinedby an entrance slit system of Ta.

The incoming particle was identified by the coincident event

between two thin detectors C 1 and C2.

The particles scattered by the detector C2 were rejectedby a veto signal coming from a large pulse which was generated by the thick detector CS2
surrounding the C2 detector at the center.

The number of outcoming particle was determinedby counting the coincident event between the incoming particle and the detector C3.

The

stopping counter C3 placed behind the target position spanned a large solid angle of forward
direction and was designed to detect the unaffected projectile particles through the target aswell as the whole charged particles of reaction products, except for fission fragments and heavy
recoil fragments due to direct and compound reactions.
J!

t

o

(

!

5cm
C2 +CS25)l+2mmCI
511 plastic

sc intilla tor

2<P

LJ

plastic
sci ntillator

C4

C3

Imm
plastic

l mm
plastic~ttO/'d"@Ot"

1~:~Bea~m~:--~r::=.• •.· =.· .·.*.·.:~~~;±1~4~J)#01
n\6¢
~
2.5¢

r/ U

Ta

Fig. I.

coll i materPbshieldjPbTargetThe schematic experimental set-up. C I, C2, CS2, C3, andC4 are plastic counters.

The numbers of in- and out-coming particles were measured for the cases with the target
put on and off the location (these numbers are hereafter denoted as nin, nout and Nin, Noutfor off-and on-target measurements, respectively).
The accuracy of the data from this method is mainly decided by the magnitude of the

16difference nin' - nout for the off-target measurement, which has so far been reduced down to
10- 6 part of nin°
The double difference,~N = (Nin -Nout) - (nin - nout),

gives essentially the total fusion cross section, since the difference corresponds to the crosssection of the complete fusion which decays by emission of neutrons alone or by fission process.
When the cross section of charged particle emission is appreciable for the fusion reaction, ~Nshould be corrected for this process, which is to be measured by the detector C4 placed backward
to the target.
Table I gives a preliminary result on the 14 N (Ec.m. = 108 MeV) + 181Ta reaction.
We have also measured the fusion cross section for the 14N(ELab. = 95,110,122 MeV) + 93Nb
and 96 Mo reactions, and analysis is now in progress.

The target thickness was 2.50 mg/cm 2 .

Table 1.

f cr is detennined from the relation 0CF= 7r~2 (fcr + 1)2.

0tot is the total reaction cross section evaluated for the optical potential.

(nin - nout)/nin0.143 X 10-5

(Nin - Nout)/Nin0.934 X 10-5

aCF

1040 mb

fcr

46 ha CF /atot

0.57

17

4-4.

Statistical Analysis of lv\ultinucleon Transfer Reactions
by Heavy Ions

H. Kamitsubo

A simple relation was found to hold between the most probable Q-value, Q, and the numberof transferred nucleons, n, in the heavy ion reactions. l )In order to explain this relation, astatistical approach was applied to analyze the energy spectra of reaction products.

It is assumed

that the reaction is induced mainly in a narrow region of nuclear surface so that a very few
partial waves in both entrance and exit channels contribute to the reaction.

It is also assumed

that only the heavier product is highly excited by the reaction and a large part of the transferredangular momentum remains on it.

The energy dissipated during the collision is converted into

the internal and rotational excitation of the residual system.
The internal excitation energy is given by
U = Ei - Ef + Qgg - Ll(N, P) - Erot.
Here Ei and Ef are c.m. energies of the system before and after the reaction, respectively, Qgg
is the Q-value of the ground state transition, and Ll (N, P) is the pairing energy correction for
nucleon transfer.

The rotational energy, Erot, is a function of the transferred angular momentum

L and is written as
Erot = h2 L (L+ 1)/(21),1 being the moment of inertia of the excited nucleus.

The level density of the final system,

Wf, is a function of U and by introducing a level density parameter a and a nuclear temperaturet, it is written as
Wf(U) = -.l exp (2 VaU) , U =B a 3/ 2t3

e - 3t/2.

The cross section is proportional to this level density.

Then, putting aWr/aEf = 0, the mostprobable Q-value can be calculated as shown in ref. 2.

Provided that the only one partial wave

contributes to the reaction in the entrance and exit channels, Qm can be expressed by

Ll V c = Vi - V f,
where J1 and R are the reduced mass and the grazing distance of the system, respectively, andV is the Coulomb barrier.
respectively.

The suffices i and f are used to indicate the initial and final systems,

The moments of inertia can be detennined by comparing the calculated values of

Qm with the experimental ones.

In Fig. 1 the ratios of the moments of inertia, 1m , to that of

the rigid body are shown as a function of n.

In case of a few nucleon transfer, 1m is as small

as one fifth of l r ig and this implies that only a small number of nucleons in the residual
nucleus rotates collectively around the core and the moment of inertia of the system is small.

18

Be

Li

.• • •v

92Mo + 14N~

l00Mo+ 14N

C
t::.

1.0

- -

B
0

0

-

EL = 97 MeV

0.8o

BL = 25°

Energy spectrum of emitted

particle.~ 0.6t-:>....,E
(J )

0.4

l

0.2

gnd
Excitation energyn (number ot transferred nucleons)Fig. 1.

The ratios of the moment of inertia

Fig. 2.

A typical energy spectrum of

determined by the present method

emitted particles.

to the rigid body value.

are observed there , one corre-

Two bumps

sponds to the excitation withJ (<Trig) and the othercorresponds to the excitation
with Jrig·
However, if many nucleons are transferred, the residual nucleus will be completely excited andhave the moment of inertia as large as the rigid body value.
In reactions with a few nucleon transfer, there appears the second bump at excitation energy
higher than the first bump discussed above in the energy spectra.

As shown in Fig. 2, it ispossible to regard the second bump as that which corresponds to the excitation with J rig.

References
1)

T. Mikumo: Proc. Int. Symp. on Cluster Structure of Nuclei and Transfer Reactions Induced
by Heavy-Ions, Tokyo, p.617 (1975).

2)

H. Kamitsubo: ibid. , p. 623 .

19

4-5.

Anomalous Angular Distribution

in the Transition to the2S 1 / 2 State in

17

0

and

13N

T. Motobayashi, I. Kohno, K. Katori,
M. Yoshie, T. Ooi, and H. Kamitsubo

Recently, an anomaly has be~n reported in the angular distributions populating 2S 1/ 2 statesof 13C and 13N in studies of the reactions 12 Ce

4 N, 13N)13Cl) and 12C

eOB, 9Be) 13 N 2 ) respectively.

In these studies it was found that exact finite range DWBA calculations assuming a direct onestep transfer reaction mechanism gave theoretical angular distributions which were oscillating outof phase with the experimental ones.
studied the reaction of 16 0e4

together with the reaction 12CN, 13N)e

4

To provide further information on this anomaly, we
17

0 leading to the 2S 1/ 2 state in 17 0 (Ex = 0.87 MeV),

N, 13C)13N

to the 2S 1/ 2 state in 13N (Ex = 2.37 MeV).

A comparison between these two reactions is of interest for two reasons. (i) The 2S 1/ 2 state in17

0 is a better example of the single particle state than that in 13N.

(ii) In the 14N + 12C

system, strong inelastic scattering channel going to the first 2+ state of 12C can make some

b

6

0.1

scattering

0.1.,.......

-E
L..

Ul

. .0

'-"

c:

~ 10

o

"0

3.55 MeV(1 d5/ 2)

o

o

00000
0

o

10

Fig. 1.

20

8 eM

30

40

10 20 30 40 50

Aru
Angular distributions obtained by bombarding 14 N on 16 0 (left hand side)and 12 C (right hand side) at 79 MeV. The solid line in the elastic scatteringcorresponds to the optical model fit. The solid lines in the transfer reactions
correspond to the exact finite range DWBA calculation.

The dashed line

connecting the experimental points is drawn only to guide the eye.

20

~
V)

..........

...c

~0.1

~b

"l:)

10
Fig. 2.

Angular distributions of the reactions

12Ce4N, 13N)13C(5/2+), 12Cct4N, 15N)
llC(3j2-), and 160ct4N, 13C)17F (5/2+
and 1/2+). The solid lines correspond10

20

to the exact finite range DWBA

40

calculation.

contribution to the mechanism of the transfer reaction, while in the 14N + 16 0 system there isno such strong inelastic channel.
The angular distributions of other one-nucleon transfer reactions were also studied forcomparison. 3),4)
The angular distributions obtained are shown in Figs. 1 and 2 together with those of theelastic scattering.
Exact finite range DWBA calculations were performed on these angular distributions using
the computer code SATURN-MARS l. 5) We used the same optical potential parameter set,6)
V = 65 MeV, W = 20 MeV, rR = l.2l fm, fJ = l.35 fm, aR = 0.48 fm, aI = 0.25 fm, andrc = 1.3 fm, for the entrance and exit channels in both 14N + 16 0 and 14N + 12C systems. The
solid lines for the elastic data in Figs. 1 and 2 show calculations using this parameter set.
The bound state potentials were of Woods-Saxon form with ro = 1.2 fm and a = 0.65 fm andthe potential depth was adjusted by the separation energy method.
13N, a small binding energy of 0.05 MeV was assumed.

For the unbound states of

The calculated results are shown bysolid lines in Figs. I and 2.
The angular distributions for the reactions other than the transitions to the 2S 1/2 states arereasonably fitted by the calculations.

The products of two spectroscopic factors Ci Sl 'C~ S2 andthe spectroscopic factor C~ S2 are listed in Table l.

To extract the values of C~ S2, we usedthe values of ci S 1 predicted for the ground state of 14N by Cohen and Kurath. 7)
In the case of the 2S 1/2 states of 17 0 and 13N, the phase of the calculated angular distribution~
does not agree with that of experimental ones.

8

Based on the result of the full recoil analysis )21

Table 1.

Spectroscopic factors obtained by comparing theexperimental cross sections to the DWBA calculations.
Reaction

J'1T

16 0 ct 4 N, 13N) 17 0

5/2+

0.71

1.03

ci SI·C~ S2 C~S2

1/2+

0.38

0.55

16 0 ct 4 N, 13C)17F

5/2+

0.49

0.71

12C ct 4 N, 13N)13C

5/2+

0.33

0.48

12C ct 4N, 13C)13N

5/2+

0.21

0.30

1/2+

0.23

0.33

3/2-

3.80

2.70

12C

e

4 N,

IsN)llC

using a complex-energy eigenstate for the reaction of 12C ct°B, 9Be) 13 N 0/2+), the assumption ofsmall binding energy for the unbound 2S 1/2 state of 13N is expected to give little change in thephase of the angular distribution.

Other choice of optical parameter sets affects only the

amplitude of the oscillation in the calculated angular distributions, and produces no change in thephase itself. The values of Ci SI ·C~ S2 and C~ S2 are also listed in Table 1.
A multi-step reaction mechanism can make some contribution to the transition to the 2S 1/2
states as suggested by DeVries et al.I) If the [ 12 C(2+) ® d s/2 ] configuration is contained in the
1/2+ state of 13N, the process via strong inelastic excitation of the first 2+ state in 12C is shouldbe important. However, since the anomaly is observed in both 13N and 17 0, this process can be
excluded to explain these anomalies, since such a strong inelastic scattering channel does not exist
in the 14N + 16 0 system.

References
1)

R. M. DeVries, M. S. Zisman, J. G. Cramer, K-L.

Liu, F. D. Bechetti, H. Homeyer, D. G.

Kovar, J. Mahoney, and W. von Oertzen: Phys. Rev. Lett., 32, 680 (974).
2)

K. G. Nair, H. Voit, M. Hamm, C. Towsley, and K. Nagatani: ibid., 33, 1588 (1974).

3)

T. Motobayashi, I. Kohno, S. Nakajima, M. Yoshie, K. Katori, T. Mikumo, and H. Kamitsubo:
IPCR Cyclotron Progr. Rep., ~ 19 (1974).

4)

T. Motobayashi, I. Kohno, T. Ooi, and S. Nakajima: ibid., ~ 65 (1975).

5)

T. Tamura and K. S. Low: Compo Phys. Comm., 8, 349 (1974).

6)

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

7)

S. Cohen and D. Kurath: Nucl. Phys., A101, 37 (1972).

8)

L. Ray, W. R. Coker, and T. Udagawa: Phys. Lett., 56B, 318 (1975).

22

CAN, 13 C)

The

4-6.

Reactions on sOTi, 52Cr, and 5A Fe

s. Nakajima, M. Yoshie, T. Motobayashi, and I. Kohno

We measured differential cross sections of the ct 4N, l3C) reactions on 50Ti, 52Cr, and 54Fe
using a 14N (Elab = 70 MeV) beam, and obtained angular distributions for the transitions to theseveral excited states of the residual nuclei. We also measured angular distributions for theelastic scatterings of 14N by these targets.

Analyzing the observed scattering data with theoptical model, we deduced the potential parameters as listed in Table 1. They vary smoothly
Table 1.

Optical potential parameters used in DWBA calculation.
V(MeV) W(MeV) rR (fm)rI (fm) aR (fm)aI (fm)14N + 50Ti

100

10

1.13

1.2

0.5

0.5

14N + 52Cr

100

10

1.135

1.2

0.5

0.5

14N + 54Fe

100

10

1.14

1.2

0.5

0.5

I

--f--- -

\

-

I---

--1-----~~~_+~--~-+-~-+-1---~--~_+_4-

\

I

\

\ (

/

~
..0

E

2/\
"2/ \ / 2\V\ 1i"\\I 1\I

~

2

-f---

'-\

-

9:

--

50Ti (l4N, 13C) 51V
Ex=2.4MeV,1 \ /:\ It!~'! r '--:-\ . ~I,

1--+---+",I1 -+--+--+--+--+---+-' ~

I

.'l~

ell
'"<j
"'b

'"<j

i

/

1\

j

\

\ .

Fig. 1.

\

Angular distributions obtained
for the transitions to the 2P 3/2

I

,

--=-~

states in the 50Ti, 52Cr, 54 Fe
ct 4N, l3C)5l V, 53Mn, 55Co
reactions.

o

10

20

30
Oc.m.( deg. )

40

50

60

The solid lines

indicate DWBA calculations.

23with target mass.

We used them in DWBA calculations for the ct 4 N, l3C) reactions.

These

calculations were performed with the code SATURN-MARS-I developed by Tamura and Lowl)
and compared with the experimental data.
each angular distribution.

The agreement was found to be pretty well for

An example is shown in Fig. I.

To calculate the absolute magnitude,

we employed such a normalization factor N as listed in Table 2.
the residual nuclei are also presented in Table 2.

The spectroscopic factors for

It is possible to put N = I for every transition

to the ground state by adjusting bound state parameters.

But for s3Mn the parameters become

too small with such an adjustment.
A large N value for the transition to the higher excited state was obtained because ourmeasurement was not good enough to resolve higher excited states.

Table 2.

Spectroscopic strengths and the normalization factor N used in the calculation.
The normalization factor is defined by N = (da/dn)exp/(da/dn)DWBA'
Spectroscopic factor(2J f + I )C 2 S *

N

{~.4

6.0

0.8

1.7

0.8

1~.4
3.7

3.3

0.6

1.7

0.6

2.6

1.0

0

1.9

1.0

2.2

1.1

1.14

3.3

2.2

2.0

Excitation energy (Me V)
SOTict 4N, l3C)SlU

S2Cr( 14N, 13C)s3Mn

s4Fe ct 4N, l3C)ssCo* Taken from B. Cujec, and I.M . Szoghy : Phys. Rev., 179, 106 (1969); B.l. O'brien, W.E. Dorenbusch,
T. A. Belote, and 1. Rapaport: Nucl. Phys., A104, 609 (1967).

Reference
1)

T. Tamura: Phys. Reports, 14C, 59 (1974).

24

4-7.

Two-Step DWBA

Treatment of Heavy Ion Transfer Reactions

T. Kammuri, H. Yoshida, and S. Yamaji

Importance of the multi-step processes in heavy ion reactions is now well recognized.

The

program code "FRATS" introduced here calculates the two-step DWBA cross section in its fullrecoil form.

The DWBA amplitude for the process a + A ~ c + C ~ b + B is given by

The nuclear matrix element of the first step is decomposed as~ ¢~¢~ Va ¢A ¢a d~ =2: (IA MA j mI lle Me ) (2 milll

X

1

(Sc mc Sl mS1 1s a ma)

S1

ms1 j 1 m 1 )1

G~ ~~ lhmill (re, ra)in terms of the form factor with specified transferred quantum numbers (Plsd 1).
is the relative distance between a and A.
case of one-step DWBA.l)

Here , e.g. , fa

Multipole expansion of G was carried out as in the

Defining G~)S2h (fb , f ' c) of the second step and expanding thedistorted waves and Green's function in multipole series, we get the four-fold radial integral tobe evaluated numerically.

With the code "FRATS", we can study the inelastic scattering effecton the one-particle transfer, the successive and simultaneous transfer processes and the nonorthogonality term in the two-particle transfer.
As an example , we present results of calculations on the 19Fct60, lSN)2°Ne 4+ reaction at
68 MeV incident energy?)

The one-step transition to the lowest 4+ state in 20Ne is essentiallyforbidden by the angular momentum conservation.

With the aim of comparison with the

19F (l60, 15N ) 20 Ne 4 1
Elab= 68 MeV

'"
'--

E 10-

1

10-2

Fig. 1.

An example of two-step DWBA
calculation.

Experimental points

are those of Ref. 2.

25exact-finite-range CCBA calculation,3) we have taken account of the one-nucleon transfer to the
20 Ne g.s. or the 2+ state followed by the inelastic excitation to the 4+ state. The opticalparameters used are: V = 100 MeV , 'R = 1.11 fm, aR = 0.48 fm, W = 27 MeV, '1 = 1.26 fm,
and a] = 0.26 fm.

The deformation parameters used for 2°Ne were {32 = 0.45 and (34 = 0.15.

The spectroscopic amplitudes for the 19p 1/2+~2°Ne 0+ and 19p 1/2+~2°Ne 2+ were taken to
be 0.58 and - 0.58 respectively. 3)

The calculated result is compared with experimental data in

Pig. 1, where the normalization factor is about 12. The magnitude of the cross section issmaller by a factor of about 3 than the value given in Ref. 3. The difference is probably due toour selection of only one set of the quantum numbers (£1 s Ij 1£sj).

References
1)

H. Yoshida: Private communication.

2)

P. Pougheon, G. Rotbard, P. Roussel , and 1. Vernotte : Phys. Rev. Lett., 34, 158 (1975).

3)

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

26

4-8.

Exact Finite-Range DWBA Calculations for the Reaction

6°Ni (l80, 160 ) 62 Ni

9·s.

T. Takemasa

Recently a new attempt 1) was made on a finite-range full-recoil distorted-wave Bornapproximation (DWBA) calculation by use of a microscopic form factor for heavy-ion induced
two-nucleon transfer reactions.

The method utilizes a multipole-series expansion of the two-nucleon

overlap as a function of the relative angular momentum £ of the transferred nucleon pair. Thismethod has been applied to the reaction 6°Ni 8 0, 160)62Nig.s. at E = 65 MeV 2) to study the

e

60 N

i (18 0, '6 0 )62N i g. s.

E= 65 MeV

10 3

6°Nj(180, 16 0 ) 62 Ni g.S.

E= 65 MeV
10

2

1 000

'"
c:

- - Fu II recoil

::>

-e

- - - No recoil

0

c:::
-0

...

'-

~ 101

~

~
~

~
b

-0

100

,f

,I"

,

J

1~!I~

\I

100

\

\
~

\

Scm. (deg.)

Fig. l.

Plot of the differential crosssections of the reaction
6°Ni

e 0 , 160)62Nig.S. for each
8,,"\

Sc.m. (deg )Fig. 2.

Comparison of the differential crosssections obtained from no-recoil(Ref. 2) and full-recoil DWBA

relative angular momentum of

calculations with experimental dataa transferred nucleon pair .e.

(Ref. 2).

Both curves are arbitrarily

normalized to the experimental data.

27

effect of recoil on the shape and magnitude of the differential cross sections employing thesurface transparent "Brookhaven" potentials. 2)
In Fig. I, we plot the differential cross section for the individual'£ to exhibit the accuracyof our method for the reaction 6°Ni 8 0, 160)62Nig.s .. As can be seen, the convergence of the
7 series is rapid. The cross section obtained by a coherent superposition of the multipolese'£ = 0, I, and 2 ensures an accuracy of better than I - 2 %.

This result indicates that our

method is practically suitable for analyzing experimental data.

In the followings we present theresults calculated taking into account up to the f=

3 tenn.

In Fig. 2, the differential cross sections obtained by the full-recoil and no-recoil calculations
are compared with the experimental data. 2) The normalization constants N = a (8)exp/a (8hheor
are 3.9 and 15.0 for the no-recoil curve and the full-recoil one, respectively.

In both calculations

use is made of the same two-neutron transfer amplitudes for the oxygen and nickel nuclei.

In

Ref. 2 the three active single-particle states 2P312, 1f5/2' and 2Pl12 were taken into account for
the Ni.

The no-recoil calculation gives the cross section larger than the full-recoil calculation bya factor of about 3.8.

The shape of the angular distribution calculated by use of the full-recoil

DWBA is in good agreement with the result of the no-recoil DWBA calculation at forward
angles.

At larger angles, however, the difference between the no-recoil curve and the full-recoil

one becomes larger and, in addition, the recoil effect diminishes oscillations in the angular
distribution for angles greater than about 45°.

Moreover, the agreement between the experimental

data and the full-recoil DWBA curve becomes poorer for angles greater than about 30°.
Finally, we have examined the dependence of the differential cross section upon theSONi (180, IS 0 )S2Ni g.s.

E= 65 MeV
0.1

Full recoil

28

configuration mixing.

The five active single-particle states, 1f 7/2 , 2P3/2, 1f 5/2 , 2Pl/2, and Ig9/2

are taken into account in calculating the spectroscopic amplitude for the Ni system.

Figure 3shows a comparison between the calculated results based on the three and five single-particle
states.

The almost complete agreement between two curves is a clear indication that theincrease of the amount of the configuration mixing for the Ni nuclei does not give any improvement
in both the shape and magnitude of the differential cross section.

The discrepancy in magnitude

between theory and experiment indicates the need to correctly treat the two-nucleon transfer
form factors 3 ) and also to take into account the two-step (successive) mode 4 ) in calculation of
the transition amplitude.

References
1)

T. Takemasa: Phys. Lett., i5B, 28 (1975).

2)

M. J. LeVine et al.: Phys. Rev., CIa, 1602 (1974).

3)

D. H. Feng et al.: Phys. Lett., 47B, 477 (1973).

4)

T. Udagawa et al.: Private communication.

29

4-9.

16

Analysis of Elastic Scattering of0

by 19F (2)T. Motobayashi and B. Imanishi

We analyzed elastic scattering of 16 0 by 19F by the coupled channel method considering an
exchange process of 160-core. The formalism of this method has been discussed previously. 1)
Here we report the results in case of the full recoil calculation.
Figures I and 2 show the results of the calculations using potentials of type A (r = 2.0 fm
and a = 0.65 fm) and type B (r = 1.3 fm and a = 0.7 fm) for 160-t interaction.

The dashedlines in the figures are the results of the calculation of heavy-ion approximation with the samecfp values as in the full recoil calculation.

r
19

21.4 MeVIn Fig. I (type A potential) the cfp value (0.25) is

-, -

F

( 16

0

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

0 ) 19F

,16

, ---

-

21.4 MeV

0.1

,: \

.... \/'..\:" : ,f,.!

! \ : \ f'type A

type B- - full reco i I
0.01 ,-- - full recoil
0.01 - ------- no recoi I------- no recoi I

! ;

:,

\ I',
1: ~ :.~ ~~'-n': ~
", I

1 J
I J
II
I,
11
II

II ,I

~,

\1

f

"

II

If
II
II
II

\1

o

60

90

120

150

180

o

8 CM

Fig. I.

'--_----L..

L - _ . . . . . L . . -_ - - ' -_ _

30

60

90

120

,

150

180

8CM

Angular distributions of elastic
scattering of 16 0 on 19F at threeenergies calculated by a coreexchange model.

30

The solid lines

show the results of the full-recoil
calculation and the dotted lines
the results of the no-recoil one.
Type A potential is used (theparameters are given in the text).

Fig. 2.

The same as Fig. 1. Type B
potential is used.

30
taken to be the same as the one used in the full recoil analysis of the reaction 19F eHe, 6 Li) 16 0
by Strohbush et al. 2 )In Fig. 2 (type B potential) the cfp value (0.75) is determined so as togive a best fit to the data.
As seen in Figs. I and 2 the recoil effect is important in determining the amplitude ofoscillation in the angular distributions, while it does not affect the phase of oscillation.

The

effect presented here is strong even at lower incident energies and appear to be stronger for the
short range potential (type B) than for the long range one (type A).
to understand by a usual

criterion 3),4)

Such effects are difficulton the no-recoil approximation:k «Mirna,(1)

where k denotes the wave number of relative motion between two incident nuclei and a theforce range of the interaction between 16 0 and triton. M and m denote the masses of 16 0
and triton respectively.
In order to understand the recoil effects mentioned above, we consider the adiabatic
approximation employed in the PSS method,S),6) which is equivalent to the no-recoil
approximation.

t

In this method, one may choose the vectors Rand
which represent the system,
denote the distance between 16 0 and triton and between two 16 0 nuclei

where Randtrespectively.

In the asymptotic region of "t, the operators h2 dxLlR/M and h2 Ll~/M remain in the--+ --+--+

total Hamiltonian, and in the adiabatic approximation the former may be neglected comparedwith the latter if the following condition is satisfied:

K«

k,

(2)

where K represents the wave number corresponding to the bound state wave function.

This isa new condition 7) for the validity of the no-recoil approximation, which would be invalidated indecreasing incident energy or in increasing K.
range of the interaction is small.

A large value of K is expected when the force

Thus, the relation (2) explains the reason why the no-recoil

approximation is invalid in the present case even if the relation (1) fails, and this can beunderstood from Table 1.
Values of K, k, and Mirna (fm- 1).

Table 1.
Pot.

Pot.

A

B

,

K.

k

Mirna

K

k

Mirna

21.4

2.2

0.21

1.1

3.0

0.21

1.6

25.8

2.2

0.97

1.1

3.0

0.97

1.6

32.0

2.2

1.53

1.1

3.0

1.53

1.6

Elab (MeV)

The values of k are calculated at r = 8.8 fm for the respective bombarding energies.

31
References
1)

T. Motobayashi and B. Imanishi: IPCR Cyclotron Progr. Rep., L 24 (1974).

2)

U. Strohbush, W. Schnidt, and G. Huber: Nucl. Phys., A163, 453 (1971).

3)

P. J. A. Buttle and L. J. B. Goldfarb: ibid., 78, 409 (1966); A176, 299 (1971).

4)

R. M. DeVries and K. 1. Kubo: Phys. Rev. Lett., 30, 325 (1973).

5)

W. Von Oertzen and W. Norenberg: Nucl. Phys., A207, 113 (1973).

6)

See, for example, N. F. Mott, and H. S. Massey: "Theory of Atomic Collisions", Clarendon
Press, Oxford, p. 153 (1953).

7)

B. Imanishi: Proc. INS-IPCR Symposium on Cluster Structure of Nuclei and Transfer
Reactions Induced by Heavy Ions, Tokyo, 1975, Ed. H. Karnitsubo, 1. Kohno, and T.
Marumori (IPCR Cyclotron Progr. Rep. Suppl. 4, p. 381 (1975).

32

4-10.

lv\ulti-Step Core-Exchange Analysis of

16

0

+

18

0

Scattering by Full-Recoil Calculation

B. Imanishi and K. Kubo*

In this report, it is shown that the recoil effect due to the transfer of two neutrons from
18

0, which is not taken into account in the LeNO treatment, is important for reproducing theobserved variation of the backward cross section of 16 0 + 18 0 scattering.1) ,2)

It is also shownthat the effects due to the multi-step process of core-exchange are small.
The coupled integro-differential equation is numerically solved under the following threeassumptions:i) Two neutrons in the sd-shell of 18 0 ground state are transferred as a 1 S di-neutron.

ii) The optical parameters of 16 0 -18

0 potential are taken from the work of Siemssen et aI. ,3)

which are determined from the analysis of 16 0 + 18 0 scattering in the forward angular region.
They are: V = 100 MeV, ro = 1.2 fm, a = 0.49 fm, W (volume type) = 40 MeV, rw = 1.2 fm,
and aw = 0.32 fm. iii) The potential V nc is chosen as Vnc = -89.094 MeV/(l + exp((R - 3.15)/0.65), from which the di-neutron bound state wave function l/In£(R) with (n£)(2s) is determined for the ground state separation energy of -12.18 MeV.
Using a constant value, 0.8, for the fractional parentage coefficient (cfp), < 18 0 IJ1 6 0, 2neS»,

we have carried out two calculations: one is the calculation with full-recoil and the other is with
the no-recoil approximation.

In Fig. 1, the results are shown together with the experimental data

for four different incident energies. The result obtained with no-recoil approximation (shown by
the dashed lines) overestimates the backward cross sections at the higher incident energies.

That

is, as the incident energy increases, the backward cross sections calculated with no-recoil
approximation increase faster than those observed.

However, the full-recoil calculation (shown by

the solid lines) gives good fits to the experimental data for most incident energies and angles.
The value of cfp, 0.8, used in the present calculation is about 1.6 times that obtained fromthe shell model wave functions .4 )Such an overestimated value may be required as a consequenceof the simplified treatment of the composite particle transfer reaction.
In order to see whether or not the multi-step core exchange process is important, the results
obtained above have been compared with those calculated in the first order perturbation treatment.
In Fig. 2, such comparisons are made for two different incident energies.
the effect from multi-step exchange is rather small.

It is then found that

The result is not changed in the calculation

using a shallow optical potential with "weak" imaginary strength.

This fact contrasts with theresult given by DWBA treatment with Buttle-Goldfarb approximation, in which the shallow
optical potential emphasizes the core-exchange effect too much.

It is also found that thecontribution from the non-orthogonality term is negligibly small.

The cross sections calculated

without the non-orthogonality term are very close to those with the full kernel (the solid line in
Fig. 2).

This result is consistent with the fact the multi-step exchange effect is very small.

* University of Tokyo33
18

0 T 16 0

Deep Opt Pot

10 -- - Full Recoil------ No Recoil

Eern=
12.7 MeV

148 MeV

11----.

Coup led Chonne l
I Full Kernel
I Non -Orthe. - 0
One - Step transfertCPT

16.9 MeV<"ol} 160. 'S-di-neutroo) =0.8
Deep OptPot

Icy l

IO-1I----~~-\-----_____J~\_I_l19.8 MeV

1()2 f - - -- - - - - -\-I--\I- - ----l90°

Fig. 1.

Angular distributions of 16 0 + 18 0

Fig. 2.

Calculated angular distributions

elastic scattering for four differentof 16 0 + 18 0 elastic scattering

incident energies. Two results offor two different incident energies.

calculations with no-recoil approxi-

The solid lines show the results

mation (shown by the dotted lines)

calculated with the full kernel

and with exact recoil treatment (theresponsible for the core-exchangesolid lines) are compared with theprocess. The dotted lines show

observed values. The experimental

the results calculated in the firstdata are taken from Ref. I for theorder perturbation treatment.

first three energies and from Ref. 2
for the last energy (19.8 MeV).

34

References
1)

C. K. Gelbke, R. Bock, and A. Richter: Phys. Rev., C9, 852 (1974).

2)

R. Vandenbosh, W. N. Reisdorf, and P. H. Lau: Nuc1. Phys., A230, 59 (1974).

3)

R. H. Siemssen, H. T. Fortune, A. Richter, and 1. W. Tippie: Phys. Rev., C5, 1839 (1972).

4)

S. Kahana: ibid., C5, 2120 (1973).

35

4-11.

170(160,160)170*(1/2+)

The Multi-Step Effects ofInelastic Core-Exchange Scattering

B. Imanishi, H. Onishi,* and O. Tanimura**

We analyzed the elastic and inelastic scattering processes, 16 0 - 17 01) and 170e60, 16 0)
17 0 *(1/2+, 0.871 MeV),2),3) by the method of coupled channels. 4 )The form factor was calculatedwith no-recoil approximation (but without the Buttle-Goldfarb approximation).

We showed thata shallow optical potential is well applicable both to the elastic scattering and the inelastic
scattering if the multi-step transfer processes at least up to the fourth order are taken into account.
Also, it was shown that the multi-step processes, especially multi-step transfer processes, areimportant in explaining not only the angular distribution of the inelastic scattering cross section
but also the magnitude of the elastic and inelastic differential cross sections. 7)
It is assumed that the system is composed of

ct 60 + n) + 16 0 in which 16 0 is assumed to

be an inert core. The ground state of 17 0 is a Is 1l2 -single-particle state.

The corresponding

neutron single-particle wave functions are designated by 1/1 Ods 12 (R) and 1/11 S1l2 (R), respectively.
Then a trial wave function 1/1 of the total system is expressed 4 ) as
1/1 = (1 + core-exchange operator) L

1

i

where

¢i(r,R) = [I/IOd s/2(R), Y..e(r)]JM

or

(r)

U·

¢i (r, R),(1)r[I/IISI/2(R), Y..e(r)]JM and the channel quantum

number i denotes (Od s12 ,.e, JM) or (1 S1l2 ,.e, JM). The symbol r stands for the direction of thedisplacement vector r between 16 0 and 17 0. We used the following interaction potential between
16 0 and n in the effective Hamiltonian of the total system:-53.0023.65 d1
V (R) = 1+exp ((R _ 3.15)/0.666) + (.eo s) -R- dR' -1-+-ex-p-(-(R---3.-15-)-:-/0,----.6-,--6-,---6.,---) (MeV),(2)

which was determined so that the binding energies of the Od s/2 - and 1S1l2 -orbits are the observed
neutron separation energies, 4.412 MeV and 3.272 MeV of the ground state and the 1/2+ stateof 17 0, respectively, and at the same time the d -resonance in the scattering of n on 16 0 occurs
3/2

at the observed energy of Ecm = 0.94 MeV.

The optical potential U (r) between 16 0 and 16 0

is assumed to be of the Woods-Saxon form.

We tested two sets of the optical parameters whichwere given by Siemssen et al. 5 ) by the analysis of elastic angular distributions.
one is a shallow potential (type A; rr = rw = 1.24 fm,

ar = aw = 0.49 fm,

Of the two sets,
rc = 1.25 fm,

V = -(12.0 + 0.25E cm ) MeV, W = -(0.4 + O.IE cm )MeV) and the other a deep potential (typeB; rr = rw = 1.20 fm, rc = 1.25 fm, ar = 0.49 fm, aw = 0.32 fm,

V = - 100 MeV, W = -40 MeV).

We carried out the coupled channel calculation (we denote it by CC) and compared theresults with those of the optical model plus DWBA (we denote it simply by DWBA). The
curves calculated on the assumption that < 17 01} 160, n(Od sJ2 » = < 17 0 * I} 16 0, n(1s1/2) > = 1* Hosei University** Nihon University

36

S(Oll(lI2)'SUI1I2)' LO( ~IoIA

101c--- - - -l0r -----

10 ~ ---------:,

IO f------~

OI(f':-----9(f-------IIw:!

(a)

(b)

(a)

(b)

Fig. 1. Comparison of the calculated angularFig. 2. The inelastic scattering calculated by

distributions with the experimental

only the transfer interaction (a) withresults of Ref. 2. The solid lines

shallow optical potential and (b)show the results of coupled channels

with deep optical potential. The

and the dotted lines those of DWBA.

dotted

lines

show

All the cfp-values are taken to be(DWBA)

withonly the one-step

unity in the calculation. In (a) atransfer, while the solid lines theshallow optical potential (type A) is

results (coupled channels) with theemployed, while in (b) a deep opticalone- and multi-step transfers.

theresults

potential (type B) is used.

show prominent multi-step effects as shown in Fig. 1, especially in (a).

It is clear that theinclusion of the multi-step processes is necessary for fitting the data, especially in case of theshallow potential of type A.
Next, we calculated the differential cross sections by CC with transfer processes (TI) only
(Fig. 2).

Comparing Fig. 2 with Fig. 1, one finds that the result with full processes (direct-plustransfer processes: DI + TI) is not different so much from that with TI only.
interpreted as a proof of the TI-dominance in CC.

This may be

However, this is not true in DWBA as isalso clear from comparison of the corresponding curves in Fig. 2 to those in Fig. 1.

Therefore ,bumps at forward angles in CC results at Ecm = 14.42 MeV and 16.48 MeV are due to thecontribution of the multi-step transfer processes and presumably not of the direct processes. 6 )The oscillatory structure of CC angular distributions at Ecm = 11.33 MeV and 12.36 MeV is37

a result of the interference of the one- and multi-step transfer amplitudes.
At incident energies well above the Coulomb barrier, the transfers by even number steps
affect the cross section in the forward angles and the odd ones that in the backward angles(This is not true if the incident energy is close to the barrier).

Therefore , the deviation changeof the angular distribution in the backward angles away from the DWBA prediction suggests thatthe three or more steps of transfer processes are important. The bumps at the forward angles in
the CC curves in inelastic scattering cross sections indicate the important contribution of the two
or more steps of transfer.
The existence of transfer processes of more-than-three-steps suggests that resonances of thetype 160_n_ 16 0 may be formed. The possibility of such quasi-molecular resonances is yet to beinvestigated.
Finally, it is interesting to note that the results of coupled channels neglecting the DI term
(Fig. 2) agree very well with the measured cross sections at all energies and angles irrespective of
the choice of U (r).

The inclusion of the DI term destroys this agreement.

significance of this fact is not clear at present.

The reason or

A more detailed account of the present

calculation will be reported elsewhere.

References

1)

C. K. Gelbke, R. Bock , P. Braun-Munzinger, D. Fick, K. D. Hildenbrand, W. Weiss, S.
Wenneis, and G. Baur: Phys. Lett., 43B, 284 (1973).

2)

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

3)

D. Kalinsky, D. Melnik, U. Smilansky, N. Trautner, B. A. Watson, Y. Horowitz, S.
Mordechai, G. Baur, and D. Pelte: ibid., A250, 364 (1975).

4)

T. Ohmura, B. Imanishi, M. Ichirnura, and M. Kawai: Progr. Theor. Phys., 41, 391 (1969) ;43, 347 (1970); 44, 1242 (1970).

5)

R. H. Siemssen, H. T. Fortune, A. Richter, and J. W. Tippie: Phys. Rev. , C5 , 1839 (197 2).

6)

W. Von Oertzen: Private communication.

He also argued about the contribution of thetwo-step process for the bump at forward angles (Intern. Symp. on Cluster Structure of Nuclei
and Transfer Reactions Induced by Heavy-Ions, Tokyo , p. 337 (1975).
7)

B. Imanishi, H. Onishi, and O. Tanimura: Phys. Lett. , 57B , 309 (1975).

38

4-12.

D (a, pll') n Reaction at Ell'= 18 MeV

K. Sagara, * T. Motobayashi, N. Takahashi, * M. Hara,
Y. Hashimoto, * T. Fujisawa, and I. Kohno

In order to study three-body correlation at low energies, kinematically complete measurementof the reaction D(a,pa)n was performed at Ea = 18 MeV, the lowest energy hitherto tried.

To

avoid radiation damage, the target CD 2 of about 250 Ilg/cm2 was brought to a new position ineach run (""'6 hours).

Coincidence measurements were made between protons and a-particles,

and their energies and difference of flight times were recorded on a magnetic tape for later
analysis.

240

Background subtraction was made by measuring accidentally coincident events which
Sp =46.\
Sex = 8.8

200

Sp = 35.3

L

8.0

I

Sa =

??
?

120

Xl.0

80

???
<:>

40

L

j

X =60 0

???

80

X4.0

\60

?? ?~
?9 ? 99
H
?
?

160
120

200

[L

40

9¢?

En=0.03

025

¢

0

¢
0
>

:; 160~'1-..... 120.a1

Sp=36 .8
Bcx= \ 1.0

X 2.8

0..

"

80

"'-

1s 80
c::
"c::

9
?<:>?

En = 0.03

<:>

0

0..

¢

~

""b

""b

"

"
\60

Bp = 25. \Ba = \0.6

?~

80

40

X = 120 0?

En=0.08<}
Q

0

X 0.55

9

120

120

Bp=42.5
B(}'= 13.5

X 2.3

80

?

40t

¢ <}

00

4

40

En =0.02,
Ep (MeV)Fig. l.

XU

I

0..

40

~

H

kl

~

c::

"0

Bp= 44 .0! 120 -

X =90 0

E
kl

~
~ 160

L

l

°o,
8

¢

00

6

Ep

Differential cross sections of the D (a, pa)n reaction at 18 MeV.

( MeV)

The arrows withLand H show the positions of the ground states of sLi and sHe, respectively, andarrows with triangles show the minimum neutron energies.

Solid curves show theresults of calculation in SMp-a multiplied by factors indicated on the right.

39

happened among different beam bunches.
Data were projected onto the Ep axis.

Two kinds of peaks were observed, the p-a quasi-freescattering (qfs) peaks in Fig. 1 and the n-a final state interaction (fsi) peaks corresponding to
the ground state of sHe in Fig. 2.

The qfs peaks were analyzed in the neutron spectator model(SM p _a ) as 1)

where PS and KF stand for the three-body phase space volume and the kinematical factor,
respectively, and ¢d is the deuteron wave function with a cut-off radius of 5 fm.

The p-adifferential cross section (~~ )p-a was calculated using the empirical p-a phase shifts and the p-a
scattering angle Xp-a ' For the n-a fsi peaks, the same formula that is sufficed with p and n in
the right-hand side exchanged (SM n-a ) was used without the cut-off radius.
calculation are shown in Figs. I and 2.

Results of the

Although fits in shape are not so bad, absolute values
2

...

-

/

o

O'exp/ PS.to0' ( SMp- o< ) I a.xp///

(da/df2 )~_.g

/
/
/

/

40

/

H

Sp=44.0
Sex= 11.2

/

I

/

X~
2

->

~

20

O ~~--~~--~--~~--~
.--0

N

~ 40
E
~

~

~

Sp=42.5
Sex= 13.520

9o~~--~~~~--~--~~o~~

q 40
~

" 20

0~~6=OO~----~9~OO~----~12~0~O~

H

Sp= 36.8
SQ= 11.0+

2~

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

40
1

XfS

20

X

X~

,",b

Fig. 3.

(p-a)

Ratios (...) of the p-a
qfs peak height to that
calculated in SMp-a, andthose (0) to the phasespace volume normalized

Sp=25.1
SQ'=10.6

at Xp-a=60°. The
triangles had to show the

20
o

2

Fig. 2.

6

4

8value unity, if the spec-

Ep (MeV)tla tor model calculation

The same as Fig. I, except thatwere correct. The circles

the curves are those in SM n-a'show some deviation fromthe p-a elastic crosssection (--) which isnormalized at 60°.

40of the cross section cannot be reproduced.

In Fig. 3 the p-a cross section derived from the p-~ elastic scattering (solid curve) and thatextracted from the p-a qfs (circle) are compared. The latter tends to be smooth, especially atbackward angle.
The cross sections at the n-a fsi peaks (fsi peak heights) were nearly independent of then-~scattering angle Xn-~.

The dependence of these peak heights on 8 p-sHe, the scattering angleof the 4He (d, p) sHe reaction, was investigated (Fig. 4).
Ed = 9 Me V2) are incorporated.

In Fig. 4 three data of 4He (d, pa)n at

As shown in Fig. 4, the data can be divided into two groups,

those at forward (8 p_s He :S90o) and backward angles, and peak heights in each group scarecely
depend also on 8 p_sH e.
These facts might indicate that multi-step processes play an important role at such a low
energy.

A more accurate analysis is now in progress.
5•oO"et.p/ PS....

0" (SMn-a)/O"exp

4

3

o
o
o

Fig. 4.
2

Ratios (A) of the n~ fsi peakheight to that calculated in SMn~'and those (0) to the phase

1 - - - - - - - - - - - - - - - 9-oo? - - - - - - - - - - - - - - -........

0space volume multiplied by acommon factor.

The upper

three circles represent the data of
OL---~30~--6~O~~9~O--~12~O--~1~50~~
SC.M. (p - 5He)

the 4He (d, p~)n at 9 MeV.

References
1)

A. F. Kukkes, R. Wilson, and P. F. Cooper, Jf.: Ann. Phys., ~ 193 (1961).

2)

K. Sagara, M. Hara, T. Motobayashi, N. Takahashi, F. Soga, F. Takeuti, and Y. Nogami:
Int. Conf. on Few Body Problem in Nuclear and Particle Physics, Quebec, August (1974).

*

University of Tokyo

41

4-13.

24Mg Cd, p)

and 26Mg Cd, p)

Reactions at Ed = 21

MeV

F. Kakimoto, N. Nakanishi,* and H. Ohnuma

Studies of so-called forbidden transitions provide information on multi-step processes in
direct nuclear reactions. The 24Mg (d, p) 25 Mg 0.61 MeV, 7/2+) reaction is an example of suchforbidden transitions, and many experimental results have been published on this reaction.
However, the presence of multi-step processes in this transition has not yet been established.
This is because all the existing data were taken below Ed = 15 MeV and the possibility that
this level is excited by compound processes could not be ruled out. l )24Mg(d, p) reaction at Ed = 21 MeV.
at this energy.

We have studied theContributions of compound processes are presumably small

Higher incident energy has made it possible to obtain reliable angular distributions

for the levels above 4 MeV, on which there has been only scarce spectroscopic information sofar.

The 26Mg (d, p)27Mg reaction is also studied to obtain information on the deformation of

A = 26 and 27 nuclei from the spectroscopic factors of this reaction.

A momentum-analyzed 21-Me V deuteron beam from the cyclotron was used 111 theTable 1. Optical potential parameters used in the analyses.
Deuteron 2)

Proton 3 )Bound state

V

(MeV)

73.98

46.7

r

(fm)

1.145

1.24

1.24

a

(fm)

0.753

0.65

0.65

Wd

(MeV)

47.8

33.2

rd

(fm)

1.227

1.28

ad

(fm)

0.861

0.50

Vso (MeV)
rso (fm)

11.92

22 .0

25 (= A)

1.145

0.92

1.24

aso (fm)

0.753

0.50

0.65

rc (fm)

1.3

1.25

NLOC

0.54

0.85

Potentials are of the form
V (r) = Vf (x) + iWdddrf(xd) + Vso ~ df (xso . L 'S) + Vr drcoulomb,

NLOC: Nonlocality parameter.
A : The usual A factor in describing a Thomas spin orbit term.
*

Tokyo Institute of Techno logy

42

Table 2. Spectroscopic factors for the 24Mg (d, p) and the 26Mg (d, p) reactions.
24Mg(d ,p)I

26Mg(d, p)

Ex (MeV)

J17

a)

b)

c)

Ex (MeV)

J17

d)

e)

f)

g)

0.0
0.59
0.97
1.61
1.96
2.56
2.74
2.80

5/2+
1/2+
3/2+
7/2+

1.88
0.6
1.25

2.0
0.66
0.934

2.0
0.56
0.92

0.0
0.98
1.70
1.94

1/2+
3/2+
5/2+
5/2+

1.6
1.5
0.78
0.08

1.18

1.14
0.64

1.4

5/2+
1/2+

0.39
0.34

0.4

0.52
0.94

3.11

7/2+ }
3/2+(0.654)

3.40
3.41
3.90
3.97
4.06
4.28
4.35
4.71
4.72

9/2+ }
3/2-

0.98(1.83)(3/2,5/2)+ }7/2(2 .61)
9/2+
(I/2,3/2)- (0 .524)
3/2+

0.863

(3/2,5/2)+(I.87)

3.43 }
3.48
1/2+
3.49 (3/2,5/2)+
3.56
3/23.76
7/2 3.79
3/2+
3.88
4.15 (3/2,5/2)+(0.39)

4.82(I/2 ,3/2)-(0.92)

3.08
0 .78

1.6
0.15
0.07

0.18

(0.52)

0.22
1.0

1.41
5.564
0.52

a) , d) Present resultse) Ref. 6.

(3

- 0.1

b) Ref. 4.

(3

0.3

f) Ref. 7.

(3

0.1

c) Ref. 5.

(3 = 0.22g) Ref. 8.

Calculations in a truncated Id s/2 2S1!2 Id 3/2
configuration space.

experiment.

The beam current was 50 -150 nA except at very forward angles.

Self-supporting

targets were prepared by vacuum evaporation of magnesium oxide powder of enriched isotopes
with metallic zirconium powder as reductant agent.

The thickness of the targets was determinedby normalizing measured elastic cross sections to the results of optical model calculation.

The

reaction products were detected with a AE-E counter telescope which consisted of a 300 J..l.mthick silicon surface barrier detector and a 5 mm thick Li-drifted silicon detector.

Angulardistributions were measured between 10° and 90°.
In Table 1, optical-model parameters used in DWBA calculations are given.

Spectroscopic

factors deduced from the present experiment are compared with theoretical predictions in Table 2.
One can see that the present results for the 24Mg (d, p) reaction are in overall agreement withthe calculation with deformation parameter {3 ~ 0.22.
seem to favor a positive value of {3 for 27Mg.

The results for the 26Mg (d, p) reaction

The shape of the angular distribution for the

1.61-MeV level of 2SMg could not be reproduced by DWBA as expected.

In addition,

j-dependence in P = 2 angular distributions was clearly observed, which could not be explained
by DWBA either.
In Figs. 1 and 2 some preliminary results of two-step and CCBA calculations are shown. **The two-step program TWOSTP by M. Igarashi and M. Toyama and the CCBA program CHUCK by P. D. Kunz are used.

43

It can be seen that the angular distribution for the 1.61-MeV level of 25Mg can well be

reproduced by these calculations.

0.1

More detailed analyses are under way.

l.61 Me V

0.01

10

,t:

0.97 MeV0

Ex =1.61 MeV

.D

E

1

E
u

0

b\O!

""' "'"

0

00

L

0

4J
lfl

o

-

0.1

. .0

E10

5

10

.g 1i5, 0'

O.Oi\leVV

II t f/rlt+-~I--I---+-'-'-'-+--•

o
o

0

0

0

0.1

D·

w

3D·

8 c.m.

90·

8 e . m.

Fig. 1.

Angular distributions from the24Mg (d , p) reaction.

Fig. 2.

Solid lines are

the results of two-step calculation.

CCBA calculation compared with theangular distribution for the 1.61-MeV
level in 25 Mg.

References
1)

G. Brown: Nucl. Phys., A232, 125 (1974).

2)

C. M. Perey and F. G. Perey: Phys. Rev., 152, 923 (1966).

3)

T. A. Schmick, K. W. Kemper, P. K. Bindal, and P. D. Koshel: ibid., CI0, 556 (1974).

4)

R. S. Mackintosh: Nucl. Phys., A 170, 353 (1971).

5)

B. Cujec: Phys., 136, B1305 (1964).

6)

R. N. Glower: Phys. Lett., ~ 147 (1965).

7)

1. M. Lacambra, D. R. Tilley, and N. R. Roberson: Nucl. Phys., A92, 30 (1967).

8)

M. 1. A. de Voigt and B. H. Wildenthal: ibid. , A206, 305 (1973).

44

4-14.

Proton-Unbound States Exc ited by CreHe, d)Mn Reactions

N. Nakanishi

Angular distributions of deuteron were measured on the 50 ,52 , 54Cr

eHe , d)51, 53 , Mn at anSSenergy of 29.29 MeV , and many levels unstable to the proton emission were observed.1) The
angular distribution for the unbound state was found to be reproduced by employing the single
particle resonance wave function as a proton form factor.!)Another approach using an isobaric analogue doorway state wave function 2 ) was tried toreproduce the differential cross sections. To describe the behavior of the transferred proton in
the residual nucleus, the wave function is divided into three subspaces of the elastic scattering,
doorway states and compound states using a projection operator method , that is,

I'l' > =p 1'l' > +D 1'l' > +Q I'l' > ,where P, D, and Q correspond to the three projection operators.
The resultant form factor is

10'

54Cr e He, d) 55M n

EHe= 29 .29 MeV
P r oto n form factor of 55M n

10.03MeV P"2( lAS of 55C r grd pw )Ex = 10.03 (vIe\' Py;-..:

~ 10-'.DE

OJ~-......

.~~ .

b

~

12.17 MeV 9",'(lAS of 55C r 2.09 MeV Yow )10-'oFig. 1.

15

12
T

o

60

(jm )

Form factors corresponding to
the 10.03 MeV P3/2 -and 12.17

MeV g9/2+ levels of s5Mn.

Fig. 2.

Angular distributions for the
5sMn 10.03 MeV P3t2- and 12.17
MeV g9!2+ levels.

Calculated

curves (solid lines) are adjusted
to fit experimental points.

45

in which the bars of P and D represent energy-average over the fine structures of the compoundstates. The term hp is the Hamiltonian which is modified to eliminate the overlap with doorway
states from the usual optical model Hamiltonian, and the term p + is the eigenfunction to the
Hamiltonian which describes the direct breakup of the 3He particle. We can eliminate this term
noticing resonance peaks only. The summation is made over dispersing doorway states, whereV( ~), E~, r S' and 'YqP are charge-changing Coulomb force, resonance energy of the doorway
state, total width, and escape reduced width, respectively. Therefore, the second term corresponds
to the part which goes to an elastic scattering channel from the doorway states and has an
asymptotic form of the scattering state. The third term is for the doorway states and has a formof the bound state wave function of the parent nucleus.
Figure I shows the form factors corresponding to the 10.03 MeV
g9/2+

P3/2-

and 12.17 MeV

levels of sSMn. These levels are the isobaric analogue states of ss Cr ground P3 /rand

2.09 MeV 9/2+ states, respectively. Figure 2 shows the angular distributions for these levels
calculated using those form factors.
DWBA calculations were carried out using the DWBA 2-2 code. 3 )References

1)

N. Nakanishi, S. Takeda, H. Ohnuma, S. Yamada, H. Sakaguchi, M. Nakamura, S. Takeuchi,
and K. Koyama: IPCR Cyclotron Progr. Rep., ~ 42 (1973); ~ 48 (1974).

2)

M. Kawai, A. K. Kerman, and K. W. McVoy: Private communication.

3)

M. Igarashi: Code INS -DWBA 2-2.

46

4-15.

Analysisof Elastic Scattering of

3He on ~3C

T. Fujisawa, H. Kamitsubo, T. Wada
M. Koike, Y. Tagishi,* and T. Kanai**

The purpose of this analysis is to obtain the best-fit sets of optical potential parameters forelastic scattering of 3He on 13e at incident energies of 29,2, 34.7, and 39.6 MeV.

The

experimental procedure and results were reported previously. I) ,2) The optical model analysis has
been carried out with SEARCH code. 3 )The used potential is of the form:(()'L)( Ii ,d)rmn- ) drf(x .so)
+ Vc(r),
C

+Vso

•

(1)

o 39.6 MeV-.-.-.-.-..,-~...........
_.a.. _~_~-O------JJ..- ~ - -oo'"O- _ ~o~............

.............~- -- -c------

0.5 ro •__30~----r----~._a_ -_._.-.
- C==-'

0 1--.----- -f-. __"""'-.--.............
50i---- - - i - - - - -- + - - - - - - ' P""-'.-.---~............

--.--._.-.

10
O~--~----+----r-\
\

\
""-

'"

100
O~------~~------~_

0_5

Va (MeVI

Fig. 1.

Potential ambiguities given by five-

1.0

1.5

rD (f.m)Fig. 2.

Variations of WD; rR, aR,parameter search at given values ofaD, and X2 IN as a functionVo.

ofrd at Vo = 195 MeV.

* Tsukuba Univ.
** Nat!. Inst. of Radiological Sci.

47

- 1
X
f(Xi)= [l+exp(xi) J ,Xi=(r-ri M )/ai'

where

V c = Coulomb potential due to a uniformly charged sphere of radius 1.4 M1/ 3 fm.
The set of parameters was determined by varying the parameters to minimize the quantity:

2=.f [rr (8 i) - rrex·p(8 J]2,Xth

L1 rr exp (8 i )0l =where ath(Oi) and aexp(Oi) are theoretical and experimental differential cross sections at the
scattering angle ai, respectively, and Aa exp is an error of a exp 'Figure 1 shows well-known ambiguities of the optical model parameters. The fitting procedure
The initial sets of parameters were selected according to a preliminary

was as follows.

six-parameter search.

The value of V 0 was increased or decreased step by step and five-parametersearches were made for a given value of Vo. The starting values of the other parameters foreach search for a given V 0 were chosen to be the final values obtained for the adjacent value ofYo.
Since values of ID are too small at 29.2 MeV in Fig. 1 so the authors examined variations
2of X IN, Ws' rR, aR, an as a function of rn at fixed values of V 0 • Figure 2 shows the
rn-depenaence of the other parameters. We can see that the optimum points of X 2 IN vary withincident energies.
The optimum optical model parameters for the fixed value of rR = 1.1 fm are summarizedin Table 1. The differential cross section calculated with these parameter sets are compared inFig. 3 with the experiment. The following results are obtained from the comparison:c 29.2 MoW"C( 'He. 'He)D\,

1

1,- ' . 34.7 MoW
L c 31.6- MoW-'"

l\cc1~~1 ~ .

I

\. I

1\

.1

;
1

1--'--

~

1'\
I--l-

1

\ ,. ..

~,
"\.

.! 'j

\f \

r \I

f-

f--- -

I--

39.6 MeV

60

I I '

I

u

29.2 MeV

·n
!l
v
_
_
a=lt
"
,\J

0.'1 ~1--

II '

~

1/-

2J

I-- r-I--\ _C!O=ci)\:s===

1

I\, l"'I

11\):=1=er r--<D-r-

~ \6

"v

\3

h~

120

150

160

30

60

90

120

150

180

30

60

90

120

150

ac,m

Fig. 3.

-: ~~:~ ~:~ .

r·90·"C( 'He , ' He II!

K\ ..... ~CLJ V

1
I

.,

r-

'\115).

.. [Jf _\',1 "

",f4,

30

o

: :. t

I--

I, !

I

fl

:

29.2 MeV
34.7 MeV

2 - 0) -CD
f---l--

T
IP.;f>'+",

1\ .(I'\1•

I!-:h-+-t-

\

I-t1

.l

I

c

h---+---I----l----.----~

0

H I--

I--t-

1

-=r

\--'_·-+-,--L--L-- 13C('He,'He I -Ratios of the elastic scattering differential cross section to the corresponding
Rutherford cross section. Numbers indicate the potentials in Table 1 used in
the optical model calculations.

180

48

Table l.

Optical model parameters at the optimum points of X2/N.

Values of rR are

fixed at 1.1 fm and values of rso and a so are equal to those of real parts.

Vo

(fm)

(MeV)

WD

rD

aD

Vso

(MeV)

(fm)

(fm)

(MeV)

X2 IN

Data num- or

Pote ntial

bers forXl fit(mb)

number

E3He= 29.2 MeV

80.1

0.845

25.7

1.43

0.632

158

25

1093

66.9

0.896

31.0

1.44

0.595

459

52

1081

66.9

0.897

31.4

1.44

0.594

460

52

1082

104

0.798

30.3

0.378

1.09

310

52

1190

2-a

105

0.798

33.6

0,237

1.13

289

52

1203

3-a

163

0.715

18 .8

1.34

0.701

115

25

1096

138

0,706

14.6

1.1 2

0.903

425

52

1163

126

0,709

11.3

1.25

0.908

271

52

1183

194

0.690

50.7

0,0899

1,09

262

52

1185

5-a

193

0.689

52,7

0.0243

1.11

236

52

1191

6-a

1.84

3,92

7.15

2.92

E3He= 34.7 MeV

103

0.763

14.4

1.42

0.750

235

25

1131

108

0.804

13.5

0,962

0 ,991

418

64

1159

108

0 .804

13.4

0,963

0.993

417

64

1159

108

0.803

16.2

1.02

0.917

257

25

1143

1.24

7-a

182

0.651

16.7

1.19

0,859

247

25

1165

10

195

0.694

19,2

0.743

1.01

423

64

1159

II

194

0.691

20,6

0.588

1.08

322

64

11 87

12

194

0.677

27.4

0.277

1.18

214

25

1230

10-a

2.27

E3He= 39.6 MeV

I II

0.739

12 .2

1.45

0.772

74.2

25

1124

13

110

0.731

10 ,5

1.42

0.843

127

72

11 53

14

110

0.732

10.6

1.42

0.835

110

72

1149

15

195

0,634

13 .9

1.23

0.877

59.7

25

1150

16

198

0,643

16,1

1.24

0.814

3 11

72

1114

17

198

0,646

16.1

1.22

0.824

267

72

1116

18

1.75

1.33

1)

The deep potentials are better than the shallow ones at forward angles.

2)

The shallow potentials are better than the deep ones when all of the data points areused for fitting.

3)

The potentials that have particularly small values of rD are better than the others
when all the data points are used for fitting.

The following problems were pointed out to be carried on:
1)

Use of the mixture of surface type and volume type potentials to the imaginary parts.

2)

The effect of compound nucleus.

3)

The effect of coupling between the elastic channel and others.

4)

The effect of two-step process such as 13C eHe, cx)(cx, 3He) 13 C.

References
1)

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

2)

T. Fujisawa, H. Kamitsubo, T. Wada, M. Koike, Y. Tagishi, and T. Kanai:

3)

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

ibid.,~ 34(1974).

49

Effect of eHe, a) Ca, 3He)

4-16.

Two-Step Process

in Elastic Scattering of 3He on 13C

T. Matsuura

Optical model analysis of elastic scattering of 3He from nuclei has attracted much interest
because of wide ambiguity in the resulted potential parameters. I), 2) Recently, elastic scatteringof 3He from 13C at ELab = 29.2, 34.7, and 39.6 MeV has been extensively studied by Fujisawawith a standard optical model. 3) It has been pointed out that an automatic parameter search
including data in a whole range of angle (OCM = 15° -160°) ended up with peculiar geometricalparameters in the imaginary potential (e.g., rD ~ 0 fm, aD ~ 1.7 fm) which are contradictory
to the standard values of a conventional optical model (e.g., obtained in case of heavier target
nuclei),l) while standard parameter sets give a reasonable fit for forward angle data (OCM S 90°).
--j

~~-+

-

i

~l

I
-

I

-

O~iJ!

1.0

~'Q

o. 1

I

i

1\

J

1\

lJ
\

-

, --0

I~

-.l

j

13c eHe, 3He )

==

'

~,

\'. "'tibokJo o

1\\

0

\\ /

\! !

-

~.

0
0

tl.k.~
0 ,

-

\;

\I

-'--i,/

\.

I

I

i

0.0 1

"\

,
II

I

\

I

\

I

--

f---

0\'

'--rl

\

"\

.f

I"--

I

~ o_O ~~3.,

~-...

I~

l;cr

E L ab = 29.2MeV-- r--o:'Y~o-o 0 0n~~ o __ ~~'nT"
W\o- tJ;t-)tt

_~I

I

~

I

-/;~f\.- 0_

h
o

~

I

-

I

--

0

1"--1----

1

I

\
\ I
\ I

- f---

J

t-----

I

i

I
I

I
I

0

20

I

--

J

I

:

I

40

I
60

I

100
80
8 CM ( deg)

120

140

1 iO

Fig. 1. 3He + DC elastic scattering cross sections (ratio to Rutherford cross section) at ELab=29.2 MeV The blank squares
represent the experimental values of of OR. The solid and thebroken lines represent the results of optical potential scattering(Potential No. 4 in Ref. 3-conventional) with and withoutcoherent mixing of the amplitUde from (3He, a) (a, 3He)
two-step process, respectively. The dot-and-dash line shows theresult of optical model analysis using the whole range of data
(Potential No. 5-a in Ref. 3 with the peculiar parameter values
as mentioned above).

50This indicates the possible contribution of coupling of inelastic or reaction channels with 3He
elastic channel in backward angles. 4) Here re-examination of optical model analysis was intended
with explicit inclusion of the contribution from two-step process of pickup-stripping CHe, a)(a, 3He), in order to see whether or not this reaction process is responsible for theabove-mentioned peculiar parameters of conventional optical model. A preliminary result ofelastic scattering cross section (Rutherford ratio, Gel (a) / oR (a) ) with and without coherent
mixing of the two step amplitude is shown in Fig. 1.

A considerable effect is seen in backward

angles (a CM 2: 90°) since the optical potential scattering cross section drops very steeply with
angle while the contribution from the CHe, a) (a, 3He) process shows rather flat angular
distribution which becomes comparable with Coulomb scattering in large angles. Search for
optimum values of this optical model is in progress.

References
1)

T. Fujisawa, H. Kamitsubo, T. Wada, and M. Igarashi: J. Phys. Soc. Japan, 27, 278 (1969).

2)

T. Fujisawa, S. Yamaji, K. Matsuda, S. Motonaga, F. Yoshida, H. Sakaguchi, and K.
Masui: ibid., 34, 5 (1973).

3)

T. Fujisawa: IPCR Cyclotron Progr. Rep., ~ 46 (1975).

4)

J. R. Shepard, P. D. Kunz, and J. 1. Kraushaar: Phys. Lett., 56B, 135 (1975).

51

4-17.

Alpha-Gamma

Angular Correlation Measurement for
13C ( 3 He, aY) 12C (4.43 MeV)

the

Reaction

T. Fujisawa , T. Matsuura , H. K amitsubo, T . Wada,
M. Koike , Y. Tagishi,* and T. Kanai**Angular correlations of a-particles leading to the first excited state in I2C with following
gamma rays were measured for the 13CeHe, a) 12C* reaction at a bombarding energy of 29.2 MeV.
The symmetry property of the reaction matrix I) or the Bohr theorem 2) gives the relation
in a reaction A(a , b )B,
MA - MB + ma - mb = even/ odd as 6.n = even/odd,(1)where M A and M Bare z-components of spins of nuclear states A and B, ma and mb are thoseof p articles a and b , resp e ctively, and 6n( = ± I) is th e ove rall parity change in the reaction.
From Eqn. (I) there is a simple spin relation in the reaction IJCe He , a) 12C*( 4.43 MeV , 2+) as
shown in Table 1.
Ions of 3He were accelerated with the cyclotron. The beam intensity was kept below 10 nA
in order to red uce the chance coincidence.

700 pg / cm

2

The target was a self-supporting foil of 13C of about

in thickness and the purity was 90 %.

Emitted particles were detected with asurface barrier detector 2000 pm thick and gamma rays were measured with a 7.6 cm X 7.6 cm

Nal (T 1) crystal mounted on a 56 A VP photomultiplier.

The gamma detector was placedpe rpendicular to the reaction plane and shielded with a lead cylinder.
Singles spectra of a-particles were measured at the same time as spectra coincident with the
4.43 MeV gamma rays.

Then a ratio of coincidence yields to singles yield was obtained forTable 1.

Relation of spin directions of 3He and 13C, magnetic
substa te of 12 C, and 'Y-rays.

Spin directions of 3He

Magnetic substates of

Whether 'Y-rays are

and 13C

the 2 + level excited

emitted to the z

by the reaction

direction (normal to
the reaction plane)

Parallel

Antiparallel- -- - - - - - - - - - -;'Tsukuba Un iv.

**

Nat !. lnst. of Radio log ical Sci.

0, or ± 2

not emitted

Emitted

52

10 '

( a)

t
\t

~\

13C eHe. a ) ' 2C

- - - - - Potent ia l 3He - 1 and a

4. 43 MeV sta te--

Pote nt ia l 3He - 2 and a32

m = 23 X 10 'MeV F

E = 29. 2 MeV.
!

't. •••. ....

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

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

10-1..... ...........

,

,,

,
\

.. . ...

,
/

I
-- _

( b)

4

.... _ /I

Fig. 1.

Differential cross sectionsof l3c eRe , Q) 12C*( 4.43 MeV)(a) and ratios of coincident

O·

60·

30·

90·

120·

yield to the singles yield (b).

150"

8("\,

a-particles leaving 12e in the first 2+ state.

In case of the inelastic scattering, this ratio

corresponds to the spin flip probability. Figure 1 shows the angular dependence of this ratio andthe angular distribution of Ql with predicted values by DWBA?)
4

version of DWBA-2. )The code used was a modified

The optical parameters shown in Table 2 give the best fit to the elastic

scattering without spin-orbit coupling. 5),6) The values of V so differ from values given by the
optical model calculation. 5 ) The experimental values of the cross section and the correlation
function are not well reproduced by this analysis.

It is, however, noteworthy that the populationsof the magnetic sub states of the first 2+ state of 12e predicted by DWBA analysis with any setsof optical parameters are 60%, 30%, and 10% for ±2, ± 1, and 0 respectively , if it were not
any spin dependent force in the reaction.

The deviation of the observed population for ± 1

states from the constant value clealy shows the importance of spin dependent force.

Table 2.

The optical-model parameters of 3He and Q on 13e and 12e.

Potential
name

Vo
(MeV)

rR
(fm)

aR
(fm)

WD
(MeV)

rD
(fm)

aD
(fm)

Vso
(MeV)

Rc
(fm)

3He-l

105.7

1.1

0.8

24.3

0.57

1.04

8

1.4

3He-2

105.7

1.1

0.8

24.3

0.57

1.04

4

1.4

a

179

1.3

0.7

12

1.3

0.7

0

1.3

53

References
1)

F. Rybicki, T. Tamura, and G. R. Satcher: Nucl. Phys., A146, 659 (1970).

2)

A. Bohr: Nucl. Phys., 10, 486 (1959).

3)

E. M. Kellogg and R. W. Zurmuhle: Phys. Rev., 152, 890 (1966).

4)

M. Igarashi: Code I.N.S.-DWBA 2-2.

5)

T. Fujisawa, H. Kamitsubo, T. Wada, M. Koike, Y. Tagishi, and T. Kanai: IPCR Cyclotron
Progr. Rep., ~ 34 (1975).

6)

S. Yamaji, T. Fujisawa, H. Kamitsubo, K. Matsuda, S. Motonaga, F. Yoshida, H. Sakaguchi,
and K. Masui: J. Phys. Soc. Japan, 37, 1191 (1974).

54

5. NUCLER PHYSICS
N uc lea r Spec troscopy
5-1.

Gamma-Gamma Coincidence Study of the

92Mo and 9AMo + C Reactions
A. Hashizume, H. Kumagai,
Y. Tendow, and T. Katou

Observation of ')'-rays in the decay process after compound nucleus formation gives
infonnation about yrast levels and side band levels. However, many channels are opened in the
decay of compound nuclei fonned by heavy ion reactions and the ,),-ray spectra have very
complex nature.

Though its interpretation becomes rather difficult, the ')'-')' coincidence method

gives a promising means to analyze such spectra.
Enriched 92Mo and 94Mo targets were bombarded with 80 MeV e-ions to obtain moredefinite infonnation about the levels in IOoed and 102ed produced by the (e, 4n) reaction.
The detection of ')'-rays was made with 23 and 50 cc Ge (Li) detectors. They were placed atabout 55° to each side of the beam direction to avoid strong 511-511 keV coincidence caused

SingleCoincidence

500

ChannelFig. 1.

1500

1000
numberSingles ')'-ray and coincidence spectra observed
when 92Mo was bombarded with 80 MeV
12e-ions.

55

by annihilation radiations of positrons which were emitted from reaction products. Time
resolution of the coincidence which was measured using 'Y-rays from 60Co was 23 ns (FWHM).
Accidental coincidence was also monitored by opening the gate after 210 ns from coincidental
timing.
In case of 92Mo + C reaction, the coincidence gates were opened at more than 20 placesin the spectrum above 511 keY by using digital gates and the coincidence relation of 'Y-rays
was examined. The coincidences between 660, 750, 777, and 804 keY ')'-rays were confinned.
The 655 keY ,),-ray is emitted from radioactive isotopes and coincidence with the 511 keY'Y-ray was observed. Figure I shows the spectra obtained at 655 and 660 keY gates. In bothcoincidence spectra the effect of higher 'Y-rays was eliminated by opening the gate at 670 keY
and by making subtraction from the fonner spectra.
For the 94Mo + C reaction, the strong ')'-rays of 557 and 719 keY energies observed in the
singles spectrum were due to decay of radioactive isotopes and found to coincide each other.
The 666 keY ,),-ray coincides with 143, 189, and 511 keY ')'-rays. These situations are illustrat~din Fig. 2.

We are making further reduction and analyses of data stored event by event inmagnetic tapes and the infonnation on the excited levels in to°Cd and l02Cd will be obtained
together with the results of excitation functions.
Er (keY)
500

750

1000

1250

Single40
Coincidenceo500

Fig. 2.

1000
Channel number

1500

Singles 'Y-ray and coincidence spectra observed
when 94Mo was bombarded with 80 MeV
12C-ions.

56

5-2.

Cross Sections foraamy and 90mNb via
89y + aReaction (2)A. Hashizume, Y. Tendow,
T. Katou, and H. Kumagai

During the study on nuclear isomers in the ms region of half-lives, a high spin state(8+, T 1/2 = 14 ms at 675 keY) in 88y was found to be excited when 89y was bombarded
with a-particles.

The relative excitation functions and the ratios of the yield of this state to

the 382 keY (1 +, T 1/2 = 6.2 ms) state in 90Nb as a function of Ea were reported previously. 1)
As such a high spin state is not excited by a direct reaction process,2) it is believed that thestate is excited following the evaporation of a-particles from a compound nucleus.
The levels in 88y and 90Nb are shown in Fig. 1.

The ,),-ray energies from 8+ state to 5-

state and 5- to ground state were determined to be 442.9 ± 0.4 and 231.8 ± 0.5 keY
respectively. The energy of 8+ state is 674.7 ± 0.7 keY. Cross sections for the 675 keY state
2+
(4 -)
33+
(4 -)
2+
9+
(5,6) 3+
2+
(5-)
(5-)

(g%) 2+ ( p~r%)( p~ r%)( p~ P%)

1.598
1.573
1.478

I
(g% )2

1.323
1.282
1.225
1.134
1.092

( 9%2 2( p~ P%)(9% P~)

4+

(9%)2

5+
0+
8+

(g%) 2

1.952
1.913
1.881
1.832
1.765
1.705

./ 1.647
1.631
1.433
~ 1.414// 1.372
1.363,, 1.344
1.280
1.196
1.1283(2 -)(1 ) +/

0.989( p~) 2(g %) 214ms

(g%) 2

0.847
0.767
0.712
0.6747 (7 )~ 0.8543

2 +"" (g%) 2(2) +/, 0.8478
0.82750.8226(g%) 20.6512

""<I'

d

+1

0>

N

1+
( 5 -)( p~ g%) (1%) 2

""<I'
""<I'

( pU)20.2318 (5 )

1+ I
54+
5+ (9%)2
7+ (g% )2
46+ ( g%) 2

0

8+

0.394

( p~ g%)
u-..
d

+1

00

....;

4-

(PU g% )My

Fig. 1.

i

6.2ms( PU9%)

0.3824 (6)0.36240.32800.28530.17120.1248 8.8s
0.1224

MN(g%) 20
90Nb

The excited states in 88y and 9ONb. The energy of thefirst 8+ state in 88y was measured in the present experiment.

57

in 88y and the 382 keY state in 90Nb were measured using Y203 targets. The mean thicknessesof the targets were 7.40 and 5.34 mg/cm 2 . The inhomogeneity of the targets was examined by
the x-ray absorption method. The x-rays emitted from 241 Am were collimated to 2 mm </> andthe target was scanned by this x-ray beam, and the thickness of the target was corrected forthis inhomogeneity on a-beam position. In a typical experiment, the target was bombarded
with a-particles for 5.3 ms and 'Y-ray measurement was made during 40 ms starting at 5 ms
after the end of irradiation and this cycle was repeated . The time and energy spectra were taken
by a two-dimensional multichannel analyzer. The decay curve analyses give half-lives of 13.8 ±0.18 and 6.19 ± 0.08 ms for 88m y and 90m Nb respectively. The absolute efficiency curve ofa pure Ge detector in the experimental set-up was determined as shown in Fig. 2.

Thepreliminary results of the cross sections obtained are shown in Table 1.
Following a statistical model formalism developed by Huizenga and Vandenbosch 3 ) for the
calculation of isomer's ratios in nuclear reactions, programs are being developed to investigate
the yield of these isomers. For the estimation of compound nucleus formation cross sections,the transmission coefficients T.e of incident a-particles for yttrium target were calculated byusing an approximation of a parabolic potential or an optical potential. The real and imaginary
well parameters of the latter potential were taken from the experiment of Park et al. 2 ) and
10-2

10°, - - - -- - - - - - - - - -------,

Total absorption efficiency ofpure Ge
24~m

24~~

10-3

\

>.

g
<1)

'u

4~m.

<1)

c

0

't; 10-'
!

lm

<1)

"'C
<1)

::s

"0

'"

A

-<

10-'

20

'\:7CO
\S7CO

~

Ra

\
Ra

\

\60 CO

30

"

10-6

o.n

Fig. 2.

U.1
Energy of x-and 'Y-rays(MeV)

10

Fig. 3.

The normalized spin distributionof compound nucleus when

The absolute efficiency curve

89y was bombarded with a-of a pure Ge detector.

particles.

J c is the spin ofcompound nucleus, PJ c is its
probability, and the parameteris the energy of incident aparticles in laboratory system.

58

the program SEARCH was used for the deduction of T.e. Figure 3 shows the normalized initial
compound spin distribution when 89y was bombarded with a-particles.

Further analysis is inprogress.

Table 1. Cross sections to produce 8+ statein 88y and 1+ state in 90Nb.

Nuclei

Energy of stateSpin and parity

Cross section

674.7 ± 0.7

24 ± 2382.4 ± 0.6

5.8 ± 0.7mb

References
1)

A. Hashizume, Y. Tendow, T. Katou, and H. Kumagai: IPCR Cyclotron Progr. Rep., ~76 (1974); A. Hashizume, H. Kumagai, Y. Tendow, and T. Katou: Nuc!. Instr. Meth.,
11 9, 209 (1974).

2)

Y. S. Park , H. D. Jones, and D. E. Bainum: Phys. Rev.,~ 778 (1971).
J. R. Comfort and J. P. Shiffer: ibid., ~ 803 (1971).

3)

W. L. Hafner, Jr, J . R. Huizenga, and R. Vandenbosch: ANL-6662 (1961).

59

5-3.

The Decay of 119mTe

M. Yambe,* M. Hirasawa,* M. FujiokSl, M. Ohshima,*
J. Katakura,* S. Hayashibe,* and T. Ishimatsu*

The low lying level scheme of 119Sb has been investigated by means of the decay of 119mTe(T 1/2 = 4.7 days).

Internal conversion electrons and 'Y-rays were measured with an INS \[2;iron-free magnetic (3-ray spectrometer and 70 and 33 cc Ge (Li) detectors, respectively.

Eleventransitions were newly added to the decay scheme previously suggested by Berzins and Kelly 1)
and Graeffe et al. 2)
Enriched tin metal was obtained from Sn02 (118Sn 95.75 %) by the KCN reduction method,3)and was bombarded with a 44 MeV alpha beam accelerated in the cyclotron.

Radioactive

tellurium was chemically separated from the target by an ion exchange method, and the carrierfree source was spontaneously deposited onto a copper foil in a 4N-HC I solution.
Singles 'Y-ray spectra are shown in Figs. 1 and 2. Transition energies, relative intensities of

10

1o3LL.-I.IIo,,-:o--L-,:--!2=OO:--'--I:--!l)=o,...-L----:-!-14=oo,.-----L-~15=00~~16=OO,.-----L----,,~70;::-;:O:--'--1-;;:!80;::-;:O:--'-~19;:;-;OO:--'--;2~0:;:;;OO:;-'---;:;2,..;.10;-;;-O--L---;;2~20~0
Chonnnel

Fig. 1.

numberSingles 'Y-ray spectrum (lower energy part).
Singles

lOS

~

co

00

10

o
o
r---

0
q

ill

104
3

I
T
~----'--------~~

10

1

,

,~

I

:

!l

~""":l.. . ___~. ./ :102'-....

2100

2200

2300

2400

2500

3200

3300

3400

3500

3600

2600

3700
Chann elFig. 2.

2700

2800

2900

3800

3900

4000

3000

numberSingles 'Y-ray spectrum (higher energy part).

* Department of Physics, Tohoku University

60

Observed )'-rays and electrons in the decay of 119mTe.

Table 1.
),-rayConversion electron

El (keY)I)'

116.61
153.64164.30241.79270.50395.53700.35777.99818.78859.71871.51912.50942.18952.95970.92976.33979.171013.39
1048.471081.171095.811110.74
1136.83
1212.731249.741255.35
1311.901366.151391.90 0
1700.79 0
1859.33
2013.312089.712242.00f)

0.68 (4 )a)
100.3 (35)
1.94 (8)0.09 (2)(6)
42.3
0.51 (2)0.70 (6)0.10 (2)0.16 (4)0.24 (4)0.58 (5)9.44 (16)
7.69 (12)0.13 (4)0.35 (9)4.10 (11)4.55 (12)3.78 (9)4.82 (9)2.41 (7)3.38 (7)0.02 (2)
11.6 (2)100
0.26 (2)0.02 (1)0.19 (2)1.61 (4)0.05 (1)0.03 (1)0.21 (3)0.48 (2)7.08 (13)0.01 (1)a)

aK (X 10- 3 )El -E2 (keY)

E2 (keY)116.591
153.601
164.353

(91 )
(86)
(92)

0.02
0.04
- 0.05

87
49.4
136

(21 )
(9)b)
(17)

270.526395.416700.33

(42)
(80)
(11)

-0. 03
0.11
0.02

35.4
3.69
3.00

(24)
(86)
(65)

859.67

(13)

0.04

2.75

(84)

912.513942.194

(75)
(78)

-0.01
-0.01

1.75
1.52

(10)
(8)
(35)d)
(6)
(13)
(10)
(10)
(5)
(17)

_ c)
976.317979.2851013.205
1048.419
1081.32
1095.708

(87)
(84)
(90)
(87)
(12)
(80)

0.01
- 0. 120.18
0.05- 0.15
0.10

1.20
0.59
1.57
0.76
1.22
0.48
2.89

1136.718
1212.727

(91)
(68)

0.11
0.00

0.89
0.78

(6)
(2)e)

1366.339(95)- 0.191.08(19)2089.535 (132)0.18

0.134 (11 )The number within the parentheses gives the error of the number belonging to the lowest
order of most probable value .

b)

For the I 16.6 and 164.3 keY transitions , the electron intensities were normalized using thetheoretical aK of the 153.6 keV transition , which was uniquely determined to be of E I fromthe e xperimenta l K/ L ratio.

c)

Masked by the 942.2 keY M-line .

d)Corrected using the theoretical 942.2 keY M-conversion coefficient (the K I M ratio hardly
d e pends upon the transition muitipolarity).

e)

For the transitions othe r than those mentioned in b) , the electron intensities were normalized
assuming the 1212.7 keY transition to be of pure E2.

f)Line not placed in the decay scheme.

61')'-rays, and K-internal conversion coefficients are summarized in Table 1 and the proposed decay
scheme in Fig. 3.
Graeffe et a1. 2 ) suggested that the spin-parity of 1407.3 keY level was 9/2 -, which was an"intruder" state, from the internal conversion electron measurements of the 1136.8 ke V transition
with a Si (Li) detector. We obtained, however, a conversion coefficient different from their rude
data with the iron-free spectrometer. The observed conversion coefficient of the 1136.8 keYtransition is apparently not of El but of MI-E2. Therefore, the spin-parity of the 1407.3 keYstate is concluded to be 9/2+ or 11/2+.
The 1013.4 keY transition from the 2226.1 keY level (9/2-, 11/2-) to the 1212.7 keYlevel (9/2+) is expected to be of E 1, but the experimental conversion coefficient is apparently
larger than the theoretical E 1 value.

If there is no anomalous conversion phenomenon, the1013.4 keY peak should be a doublet.

On the other hand, the 1013.4 keY peak partly appearedin the ')'-'"'( coincidence measurements with the 153.6 keY photopeak gate. These facts suggestthat a part of the 1013.4 keY peak is an E 1 transition to the 1212.7 keY level and the otherpart is an MI-E2 or larger-multipolarity transition to the 1366.2 keY level.

There may be a newlevel at 2380 ke V, which is also supported by a new 972.7 ke V peak coincident with the1136.8 keY peak gate. This 972.7 keY peak does not appear in singles ,),-ray spectrum, because
it is masked by the 970.9 keY, 976.3 keY, and 979.2 keY triplet peak.
It is interesting to compare the level scheme of 119 Sb with the core-particle coupling model.

The analysis is now in progress.
The authors wish to thank Dr. A. Hashizume for his efforts with the cyclotron bombardment,
and the cyclotron crew for their operation.

19/2 11121
19/w.a...J]@J,--_ _ _ __

~

;;;

712+

5l
~

512+
38.0h.

lFig. 3.

o%Proposed decay scheme of 119mTe.

log ftEC

References
1)

G. Berzins and W. H. Kelly: Nucl. Phys., AI04, 263 (1967).

2)

G. Graeffe, E. J. Hoffman, and D. G. Sarantites: Phys. Rev., 158, 1183 (1967).

3)

F. Ambe: Private communication (1975).

62

6. NUCLEAR INSTRUMENTATION

6-1.

j3-Ray Source Mounting onto a Foil Electrode
In a

Xenon Gas Chamber

M. Ohshima, * M. Hirasawa, * S. Hayashibe, M. Yambe, *I. Katakura, * M. Fujioka, T. Ishimatsu, * and A. Hashizume

In this report, we describe a new method for f3-ray source preparation. This method is very
efficient for alkali metal or alkaline earth isotopes. We employ this method to measure theconversion electrons from the decay of 136CS.
So far, the 136CS was produced by (d, a) reaction,l), 2) ('Y, pn) reaction,3) and nuclear
fission. 4 ) Usual methods for source preparation such as vacuum evaporation, electrodeposition,
electrospraying or isotope separation methods need complex devices. Further, these methods
often require difficult and time-consuming separation techniques to obtain carrier-free sources.
The present approach, on the other hand, has the advantage of great simplicity. When a target
chamber filled with noble gas (in our case natural Xe) is bombarded with a proton beam, thereaction products (Cs isotopes) would be ionized through nuclear recoil. Under an electric field
the ions can be collected onto an electrode. Namely, the Cs ions can be attached to an electrodefoil due to its affinity, but the ionized Xe ions cannot be attached due to its inertness. The

to Beam integ ra tor--- Gas inlet

Slit boxr ; = = = --- Cool ing water

Protonbeam
14---H--- --Al stopper-llOO V

1Compressed air
Fig. 1.

* Tohoku University

Cross sectional view of Xe target chamber.

63

electrode foil can be used directly as {3-ray source.
The gas chamber is illustrated in Fig. 1. Xe gas was transferred into the chamber from astorage container by freezing the gas with liquid nitrogen. The proton beam was stopped in thechamber which served also as a Faraday cup. To obtain a suitable electric field we made themain part of the chamber of ceramics. The beam stopper and the entrance window foil werecooled with water and compressed air respectively. The electrode was made of 5 J.Lm AI foil toprevent back scattering of electrons during the conversion electron measurement and a potentialof -1100 V was applied with respect to the Faraday cup. The positive electrode was made of asemi-cylindrical Al plate.
The energy and current of the proton beam from the cyclotron were 15 MeV and 10 - 20
J.LA respectively. The target chamber was mounted behind the slit box at the end of the externalbombardment channel. The 136CS activity was made by 13 6Xe (p, n) reaction (natural abundanceof 136Xe : 8.87 %). The gas pressure was about 3 atm, and the effective foil dimension 1.5 mm
X 40 mm. The electrode current was about 10 J.LA under the beam current of 10 J.LA. After thebombardment the foil electrode was taken out and mounted onto an AI holder for f3-ray
spectrometry.
The {3-ray was measured with the INS Air.(:ore {3-ray spectrometer. Fig. 2 shows typical K and
LI, II, III conversion electron spectra for 163.8 keY transition (2030.3 keY 7- to 1866.5 keY 4+
in 136Ba). The instrumental resolution of the spectrometer was 0.05 %.

K

...
c:::
c:::

o

T··

0 100

t \ •.
t•1\(\.} \.... \
i·
.. \
.,
..-...
.....

'"c:::

+'

::>

o
U

10

Fig. 2.

Typical conversion electron spectrum
for 163.8 keY E3 transition in 136Ba.

ChannelThere remain two problems in this technique:activity collection efficiency and source

quality. The collection efficiency obtained now amounts to 20- 36 %, but this is not sufficient.
The electric field distribution in the chamber has a large influence on the efficiency. Moresuitable chamber with improved field distribution will increase the activity collection. A thicksource leads to spectrum distortion due to self-absorption of electrons. In this method acontamination such as an organic substance inside the chamber will seriously affect the source
quality. So far, a white substance can be recognized on the foil and it is rather difficult tomake the foil free of this substance. These two points are open to further improvement.

64

References
1)

Chr. Bargholtz, L. Eriksson, L. Gidefeldt, L. Holmberg, and V. Stefansson: Z. Physik, 260,
I (1973).

2)

R. Reising and B. D. Pate:

3)

S. Hayashibe, M. Ohshima, M. Yambe, J. Katakura, and T. Ishimatsu: Research Report ofNucl. Phys., 65, 609 (1965).

Laboratory of Nuclear Science, Tohoku University, ~ 312 (1974).
4)

M. Fujioka, T. Miyachi, and H. Adachi: Nucl. Phys., A95, 577 (1967).

65

6-2.

Elimination of Unnecessary Peaks by Recoil
Coincidence Technique

T. Motobayashi, I. Kohno, T. Ooi, and S. Nakajima

When we studied the reaction 160e4N, 13N) 17 01) using a Li2 C0 3 target, the peak of theground state transition of the reaction 12Cct4N, 13N)13C overlaps the peaks of the reactions
on 16 0 populating the 1/2+ and 5/2+ states of 170. In order to eliminate the peak of
12Ce4N, 13N)13C, a recoil coincidence technique was employed.

in low energy reactions studied at intermediate angles (50° -This technique has been used 2)130°), where the energies of two

particles in coincidence are relatively high. Since in our case the incident energy of 14N washigh (79 MeV), emitted particles

e N) have large yield only at the forward angles where the3e 0) is small (2-10 MeV). Therefore a main problem is
7energy of associated recoil particles

how to detect such low energy particles in sufficient efficiency.

__PI--..~"'----;~.

. \\ E, ("N)

e2
Y E

OKITAC
4500C

f

DISK

.

____ __ _recoil (17 0)----I
monitorFig. 1.

Detection system used.

Fig. 2.

Block diagram of the circuit.

Figure 1 shows the arrangement of the detectors. The recoil counter system has a large solid
angle (28 msr) to obtain large coincidence efficiency and consists of 60 J1m - 400 mm 2 SSD
and an electron suppressing magnet. As shown in Fig. 2, .6E and E signals were converted to
E + .6E and PI signals by a particle identifier, and these signals together with the signals of theenergy of recoil particle (Erecoil) were recorded on a magnetic tape. Typical spectra of PI and
Erecoil are shown in Fig. 3, together with an energy spectrum of the reaction 160e4N, 13N) 17 0
which was obtained by putting gates on the appropriate positions shown by arrows in Fig. 3. ofPI and Erecoil spectra. It should be noticed that taking the coincidence (between E + .6E and
Erecoil signals) only is not good enough to distinguish the reactions on 12C and 16 0. Informationon the energy of the recoil particles is absolutely needed in add ition.
The detection efficiency was calibrated using the elastic scattering and plotted as a functionof Erecoil in Fig. 4.

The efficiency was obtained by the relation,

efficiency =y (coincidence),
Y (single)

where Y (coincidence) and Y (single) are elastic scattering yields with and without coincidence

66

100

.

/

..-.--,

100
0.87 MeV(2s1/2 )\E.-----...... ..--,

5°2
ErecoilFig. 3.

. --~---

Coincidence spectra of particle

Fig. 4.

identification (PI), energy of recoil
particle (Erecoil), and energy of 13Nparticle of the reaction 16 0 4 N,

( MeV )

Detection efficiency of the reaction
16
0 4 N, 13N) 17 0 obtained fromeelastic scattering of 14N on 16 0.

e13N) 17 0.
respectively. The efficiency is requced mainly by multiple scattering in the target. It is seen thatthe detection in coincidence with recoil particles was achieved with more than 70 % efficiency
in the energy range higher than 2.5 MeV.

References
1)

T. Motobayashi, I. Kohno, K. Katori, M. Yoshie, T. Ooi, and H. Kamitsubo:
IPCR Cyclotron Progr. Rep., ~ 19 (1975).

2)

For example, D. Kalinsky, D. Melnik, U. Smilansky, N. Trautner, B. A. Watson,
Y. Horowitz, S. Mordechai, G. Baur, and D. Plete: Proc. of Conf. on Reactions between
Complex Nuclei, Nashville, 10, (1974); K. Takimoto, K. Fujii, J. Schimizu, and J. Muto:
Bull. Inst. Chern. Res., Kyoto Univ., 52-2, 240 (1974).

67

6-3.

Position Sensitive Multiwire Proportional Counter
with Rear Helical Cathode Wire

J. Fujita

In order to develop a multiwire proportional counter for the position sensitive detector of
the particle analyzer, a model with a cathode helical wire at the rear of anode was made andtested.
The structu:-e of the model is shown in Fig. 1.

Fifteen gold plated anode tungsten wires of

22 J..Lm in diameter and of 26 cm in length are strained horizontally with a tension of 15 g atintervals of 2 mm and soldered on the terminal end of an epoxy circuit board.

Furthermore,

eight copper wires of 0.1 mm in diameter are stretched on the upper and lower sides of theanode wire plane in the same manner to hold the electric field constant and minimize the edge
effect of the anode.
The cathode wire is wound keeping 3 mm spacing with acryl plates around an aluminumrectangular pipe of 6 cm in height, 26 cm in length, and 12 cm in depth.

The diameter, length

per turn and separation of the wire are 0.1, 384, and 1 mm respectively.

Gap spacing between

the anode and cathode is 3 mm.

Read-out taps are soldered at 5 cm intervals on the helicalcathode line and bring the position signal to amplifiers composed of one stage of SN 72733
which has a voltage ~ain of about four at 200 MHz.

22J1mt/>Cross sect ional v ie w

fr on t v i ew without fro nt brass w i ndow

go ld p l a t ed

Btungsten
2mm
spaci ngB

rl:=r=~g~~==============:: : : : : :::::::::::::==til1=D=V

K

A

6I

!

D
I

3~
1~~~~)~ll ~r :li l /
60 44

I

C

/I

3",
--=±:IE

I

6,~==~.~~~~~~~~~~~~
.
1
~H
-c

1

copper

260

H

/ JJ

A . anode wires

I.

To
3 r
/ /K

B. helical cat hod e \rirec. rectangular aluminum p ipe
D. acryl space bar

E. top aluminum co ye r
F . amplifier casec. bo tt om a luminum coyer120- -- 1- 7/~-'...."~

L

H. f I"ont b r ass w i ndo\\" \\"in\.J. acr Y! s pac e rs

K. epox \" c i r c uit board
6

L. a luminum spacersF
top vi ew without top and bottom covers

Fig. 1.

Structure of MWPC model with rear helical cathode wire.

68

The filled gas is a mixture of Ar and CO 2 at one atmosphere; CO 2 gas prevents thin anodewires from corona sparks and allows the chamber to operate at higher voltages.

The electron

avalanche caused by incident charged particles is localized at a narrow region on the anode wire.
Negative signal is induced by drifted electrons on the anode and that of opposite polarity by
gas ions on the cathode. The positive pulse propagates on the helical cathode wire with thevelocity of light and arrives at a tap in a time proportional to wire length or its turn number
between the location of avalanche and the tap.

The time interval is measured using a time toamplitude converter (T AC).
Test Results
Tests were carried out with collimated a-particles of 241 Am in a closed chamber.
(1)

Flatness of anode wire plane.

Fifteen anode wires lined at a spacing of 2 mm to cover the focal plane of 2 cm in heightare connected altogether at their ends and fed out to a charge sensitive amplifier.

Figure 2shows the dependence of anode signal amplitude on the vertical position of the source position.
The waving of flatness is due to irregular alignment of hand-stretched wires.
(2)

Relations of high voltage and CO 2 partial pressure to gas multiplication.

Figure 3 shows the dependence of anode signal amplitude on the gap voltage between anodeand cathode in pure Ar gas at one atmosphere.

Metal guard plates are inserted into the gap

ends in order to reduce leakage current from the edges as shown in Fig. 3. Gas
multiplication increases rapidly with applied voltage but at the same time noise levels go up.
High voltage above 1600 V induces destructive breakdown.

On the other hand, gas

multiplication decreases with increase of the content of CO 2 gas in the mixture as shown inWith a mixture of 70 % Ar and 30 % CO 2 theFig. 4 and CO 2 gas suppresses corona sparks.

chamber can work at 2700 V without destructive breakdown.
VA = 1000V
pure Ar at one atm.
slits

Pure Ar at one atm.

2000

3mm~

E
0

..b
10

~
e
e

0;1----..

~~

1

peak
/ F W HM
channel(..>::~
0;1

:::l

~~
...... ;;.
o

0
(

~

eM

.-.....o ....

0;1
~

0;1
.-

..,;;.

;;.
0;1

~,

E

-10

0

o

;::l

0:

~

Inserti on o f O.lmm thick N i
guard plates~ 1000...c!

(.... 1500

~

..0

'"u

'"
0...

brass window

o

..>::

Ni guard plates

~

¥

500

4mm

"'Imm
thick
re ctangn lar pipe

acry l spacero- 15 - 10 - 5

0

5

10

15

20

00~-~58o ~obo0

Fig. 2.

Dependence of MWPC anodewire signal on vertical positionof a-source.

1500

2000

2500

(V)

Vertical posi tion of a -source (mm )Fig. 3.

Dependence of MWPC anode signal
amplitude on gap voltage.

69

100

V;\ = 2000V
70 %Ar + 30%C0 2 at one atm.
O.Smm wx 1mmH s lit sa from 241A m
3mm step

R=H4
1 234 5~~

Ano de vo itage = lOOO V~~

less 2ch FWHM
( 1.6mm )

50

0<FJ

"
;:l

o

U

/ 2.6ch FWHM
(2.lmm )less 2ch FWHM
(l.6mm )

~

0.5

'"
'"
>

O.82mm / ch

;,-

'';:;

'"

O~r~__~__~O ~OO~O~
OO~~_ _~~OO~
O=~_ _ _ _ _ _ _ _ _ _~o100Fig. 4.

150
C han ne l number

200

~

0

0~----~lO~--~2~O----~30~----Th e con te nt of CO, in gas mi xtur e (% )Influence of CO 2 gas added to Ar on

Fig. 5.

gas multiplication.

Spatial resolution of
MWPC with rear helical cathode line.

(3)

Spatial resolution

Figure 5 shows a result of spatial resolution.

Starting pulse for T AC is picked up fromthe anode wire and stopping pulse from the tap on the helical line.
Since the position signal on the cathode was found very small, the content of CO 2 in thegas mixture was increased up to 30 % to apply anode voltage of 2000 V.
spatial resolution obtained is about 1.6 mm.

The FWHM of

Wire spacing less than 1 mm is necessary toobtain better spatial resolution.

The helical cathode line is directly coupled with amplifier input

resistance of 2.2 kr2 at each tap.

Since the characteristic impedance of the helical cathode is

not such a pure resistance as a coaxial cable but is a function of frequency, the condition of
no-reflection cannot be fulfilled.
false stopping pulses.

The reflected signals retrigger the discriminator and give rise to

Expansion of pulse duration in the discriminator and the stretched time of

TAC enable to select only the first one of the successive pulses as a true stopping pulse. Theenergy spectrum obtained from the anode at 2000 V has a broad range of distribution becauseof corona sparks on the anode wires and leakage currents at their ends.
is not yet measured.

Efficiency of the counter

Test is continued with another model whose cathode wire has thicker

diameter, 0.2 mm, less separation, 0.5 mm , and shorter length per turn, 204 mm , in order to obtainbetter spatial resolution and less signal attenuation which makes coverage of the wider area ofthe focal plane possible.

70

6-4.

On a

Simple Raw Data Acquisition System with a
Magnetic Tape Recorder

H. Kumagai and A. Hashizume

For 'Y-,,( coincidence experiments, the address of a multichannel analyzer requires a large
capacity such as 2000 X 2000 channels to store a two-dimensional spectrum. Because it is
impossible to occupy a computer for a long time, a system has been made to store digitalized
raw data of coincidences event by event in a magnetic tape using tape recorders for audio
frequency. The waveforms of write-in and read-out signals are shown in Fig. 1.

By using thissystem different from NRZI , FM or PM method, good performance is obtained such that theerror rate is smaller than 10-7 with 2000 bits per inch of recording density. Between ADC andwrite-in circuit a 24 bit 64 word buffer of IC memory is placed. The write-in circuit consistingof a shift register, a clock pulse generator and an encorder, is shown in Fig. 2.

The frequencyof the clock pulses can be switched to 3.75 kHz in case of a cassette tape recorder and 7.5
and 15 kHz were employed for the open reel recorder with 9.52 and 19 cm/s tape speeds. The
data reduction was made with a block diagram shown in Fig. 3.

Further details of the circuits

and their function were described in Ref. 1.

o

o

Tape
recorde r(A)(B)

Fig. 1.

Waveforms of write-in
Fig. 2.

and read-out signals.

Write-in system.

TaperecorderM. e .A .

Fig. 3.

Read-out system.

Reference1). H. Kumagai, M. Okano, and A. Hashizume: Reports LP.C.R., (in Japanese), l1. 120 (1975).

71

6-5.

Upgrading of OKIT AC-4500C

T. Inamura, T. Wada, M. Ishihara,
T. Nomura, and H. Kamitsubo

It was two years ago that an OKITAC-4500C computer was installed as an on-line

computer to analyze experimental data on nuclear reactions and structure. l )The initial core

memory size was of 16 kW and monitor and PHA system programs took up 6 kW.
were available for the data area.

This limited the utility of the computer.

Only 10 kW

The core memory

has now been extended up to 32 kW, and a temporary 32 kW system is operating.

The final

version of the 32 kW system will be completed by the beginning of next year.
Programs for the monitor and PHA systems occupy 8 kW of the 32 kW core memory andanother 4 kW will be available for additional data processing programs.
will be used for the data area only.
previous 16 kW system. 1)

The remaining 20 kW

The utility area will become twice as large as that of the

Functions of the new system are essentially the same as those of the

16 kW system, but the display on CRT is not interrupted by execution of any program for data
manipulation.
It should be mentioned that DOS 45 (Disk Operating System for OKITAC-4500) will operate

on our upgraded OKITAC-4500C.

Since this computer can be used as an off-line computer,this additional system will provide another utility in programming.

Reference
1)

T. Wada, T. Nomura, H. Kamitsubo, Y. Chiba, and F. Yoshida: IPCR Cyclotron Progr. Rep. ,~ 83(1973).

72

6-6.

Computation of Multiple Coulomb Excitation

T. Inamura

An extended computer program COULEX for multiple Coulomb excitation* has been
modified for the RIKEN FACOM 230-75 computer and tested by computing multiple Coulomb
excitation of 164Dy and 181Ta with a 84Kr beam. This computer program is based on the one
developed by Winther and de Boer,1) so that the way of computation is essentially the samewith theirs. It gives total and differential cross sections, amplitudes of sub-magnetic state wave
functions, and statistical tensors for excited states as many as ten.

An introduction ofde-orientation effects caused by hyperfine fields acting on the recoils will be made in the near
future.
To analyze gamma-ray angular distributions in multiple Coulomb excitation, a separate
program CEGAMM has been written following Winther-de Boer fonnulal) and operates on the
FACOM 230-75.

Statistical tensors for excited states which are needed in the CEGAMM arecalculated using the program COULEX and stored on a disk in direct access mode.

We cansave the computation time considerably by creating such a disk file.
The author would like to acknowledge the courtesy of Prof. W. R. Phillips of the Universityof Manchester who kindly left the computer program COULEX at his disposal.

Reference
A. Winther and J. de Boer: "Coulomb excitation", (Ed. K. Alder and A. Winther),1)

Academic Press, p.303 (1966).

*

A computer program for multiple Coulomb excitation which operates on a CDC-7600 computer at the University ofManchester.

73

6-7.

Performance of SEM (Space Environment Monitor)

for Protons

and A Ipha-Partic les

R. Nagura,* Y. Narimatsu,* and N. Nakanishi

A subsystem of GMS (Geostationary Meteorological Satellite), SEM, which is composed tomeasure solar protons on the synchronous orbit, is tested by proton and alpha beams from thecyclotron.

The function of this equipment is to identify protons, alpha-particles and electrons

from other charged particles to count the numbers of them by discriminating theis energies.
The energy is ranged between I and 500 MeV for protons, 8 and 390 MeV for alpha-particles,
and less than 2 Me V for electrons and divided into 7, 5 and I channels, respectively.
Elastically scattered protons and alpha-particles by a Au target were employed to check the
performance of the system. In the lower en~rgy_ region below the capability of the cyclotron,an Al foil was used as an energy degrader.

The detectors of SEM are composed of 300 J.lm,

400 J.lm, and three 3000 J.lm Si detectors which are labeled as D 1 , D 2 , •• , and D s , respectively,

and each of them is followed by a pre-amplifier, discriminator, and compression counter. The

Compression
counter

Logic
I

I
I

I
I

I
I

I
:

I

19is~r~r12!~!9~IL _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _Vacuum chamber, ---J-~P5v-=-7\r-- --------1
1-300V
I
I
I
I
I
I
I

,..........----I.-J'----,

Fig. 1.

Power
supplyFunctional block diagram of SEM.

~

Control room

CD Detector® Pre-amplifierQ) Level discriminater

®

*

I
I
I
I

& Logic
CompreSSion counter

Nippon Electric Co., Space Development Division

Fig. 2.
Block diagram of the present test.

74

functional block diagram of SEM is shown in Fig. 1. The detector panel, on which the fivedetectors were set, was mounted in a vacuum chamber to count scattered particles.

The energyof the beam was calibrated using elastic scattering of the analyzed beam by a very thin organic
material foil.

A counter was set opposite to the center of the detector panel with respect tothe beam axis, and was used as a monitor of the particle energy and the number. The output
of SEM was measured by an oscilloscope and a multi-channel pulse height analyzer.

A block

diagram of the present test is shown in Fig. 2.
Figure 3 shows the experimental values of pulse height observed at various incident particle
energies and calculated curves.

The measured values agree with the predicted ones very well.

As for the pulse number, the experimental values are in agreement with those of the monitoring
counter and calculated ones.
As a result of the present test we concluded that the detectors and analyzing circuits of
SEM perform the functions adequately.

80
60
40

Incident part icle energy vs pulse heightI

P 03. P'04. P05
A.03. A.04 . A.05

-20

A.02

>

10
..- 8
E 6
C1)

L

Fig. 3.

4

Pulse height corresponding to the

C1)

~

~

2

incident proton at various energies.

1.0
0.8
0.6
0.1

Symbols 0 , X, and 0
represent the measured values ofdetectors D 1 , D2 . . , and Ds ,0.2

respectively , and the curve correspond
0.6 0.8 1.0

2.0 4.0 6.0 10.0 20.0 40.0

Incident particle energy

(MeV)

100.0

to the calculated values.

75

6-8.

Model Magnet of a Separate Sector eyc lotron

S. Motonaga

A linac-injected separate sector cyclotron with four sector magnets was proposed as a best
candidate for a future HI accelerator at this institute. I) A model magnet of about 1/5 scale wasdesigned to study the magnetic field configuration which fulfills a condition of isochronism andfocusing to obtain orbital stability.
A focusing properties of an accelerator of this type were discussed for an idealized magnet(hard-edged) which gives zero field outside the sector. 2 ) Practically, the magnets have asoft-edged field contour which results from the fringing field of the magnets. Such a magnetic
field contour reduces the focusing strength slightly compared with a hard-edged sector. Thiseffect depend on the ratio of the gap to the path length in the magnet.
The shape of the model magnet is shown in Fig. 1. Materials of poles and yokes are
0.01 % carbon forged steel and 0.06 % carbon cast steel, respectively. The poles shaped into
Rogowski curve. 3 )Tentative pammeters offull scal e magnet
Sector ang leMagnet fraction
Inner beam rad ius
Outer beam rad ius
Field strenth
Magnet gap

58 cm
174 cm~ 9cm- - -y - - -- ---,Fig. l.

Shape of model magnet.

References

1)

M. Odera and H. Kamitsubo: IPCR Cyclotron Progr. Rep.,L 151 (1973).

2)

M. M. Gordon: Ann. Phys., 50, 571 (1968);
Nucl. Instr. Methods, 58, 245 (1968).

3)

H. A. Enge: Proc. 1st Conf. Mag. Tech., Stanford, p. 84 (1965).

76

7. A TOMIC AND SOLID-STATE PHYSICS

7-1.

Ar-K X-Rays Induced by 66 MeV C-Ion Impact

H. Tawara, Y. Awaya, Y. Tendow,
T. Katou, and M. Akiba

The strong dependence of K-shell X-ray production cross sections on the charge state of the
projectile was first reported by McDonald et al.,l) who showed Ar-, Kr-, and Xe-K X-ray yields
by 35 Me V F-ion impact increased drastically by changing the charge state of the ions from 5+
to 9+. Mowat et al. 2 ) also observed that, in 80 MeV Ar-ion impact, Ne-KX-ray yields increased

-

. .0

c- ions on Ar/-

Ar K X-rays...... ---I-• Present work

,/

/

•

/

+

~

Present work

/
/

/

~

o

Winters et 01.

~

21-

0

Winters et al.

_________'toe ....... -.. ......

I
I

I
I
°O~--~I----~l----_L-I----~l--~IL---~

40

EnergyFig. 1.

80

Energy(MeV)

The Ar-K X-ray production crossFig. 2.

120

(MeV)

The ratios of Ar-K X-ray production

section in C 6+ - and C4 + -ion impacts

cross sections in C6+ -impact to those

as a function of ion energy.

in C4 + -impact.

Data

at lower energies (open circles) aretaken from Ref. 3. The dottedcurve shows the relative ionization
cross section predicted by BEA
calculation. The solid curve is a
guide to the eye.

77

by a factor of 60 and Ar-K X-ray yields from the projectile by a factor 1000, when the charge
state of Ar-ions was varied from 6+ to 17+.
In the present work, we have measured Ar-K X-rays by 66 MeV (5.5 MeVjamu) C-ion impact.
The C4+-ions accelerated with the cyclotron were guided to a gas collision chamber using
a differential pumping.

By passing the C4+-ion beam through a 100 J.1gjcm 2 Ag foil, theprojectiles are thought to be in a completely stripped state (C6+), because the average charge of
C-ions at this energy is 5.91. Typical ion beam current was 10 - 30 pA and the gas pressurein the chamber was about 1.8 X 10-2 Torr.

Under this pressure, 3-4 % of C-ions were estimatedto undergo charge transfer.
In Fig. 1 are shown the Ar-K X-ray production cross sections (ax) in CM - and C4+-ion
impacts as a function of ion energy.
et al. 3)

Data at lower energies are taken froin a study of Winters

The dotted curve shows the relative ionization cross sections predicted by the binary

encounter approximation (BEA).

The fact that the observed energy dependence are clearly

different from the BEA means that some mechanisms other than the direct Coulomb ionization
work at these highly ionized heavy ion impacts with high energy.
In Fig. 2 are shown the ratios of Ar-K X-ray production cross sections in C6+-impact tothose in C4+-impact. With increasing impact energy, the ratios decrease and approach unity.
This shows that the ionization cross section at higher energies tend to be independent of thecharge state of the projectile. Similar reduction has been observed in the ratios of Ar-K X-ray
yields in 0 8+- to 0 6+- and also in F 9+- to F 7+-ion impacts with increasing ion energy. 3)
One of the reasons for the ionic charge dependence is the variation of fluorescence yields
due to multiple ionization.

However, Winters et al. 3) have shown that the fluorescence yields
may be different by at most 5 % in C6+ - and C4+-ion impacts. The screening effect of the
projectile nuclear charge by its electrons is also one of the probable causes.

The screening effect,

however, becomes larger with increasing projectile energy4) and this is in opposite to the present
measurement.
The most important reason of the charge state dependence of the ionization might beelectron transfer processes where highly ionized ions capture the target electrons with a considerablyhigh probability. Halpern and LawS) argued that the agreement between the observed data andtheories can be obtained by taking the ionization cross section by naked heavy ion impact with
the nuclear charge Z, aiz, as follows:
aiz = Z2 aip + XaBK ,where aip is the direct Coulomb ionization cross section by proton impact with the same velocity
as the heavy ion, aBK is the K-electron transfer cross section of Brinkman-Kramers, and X is thestrength of the electron transfer process to the total inonization. In Fig. 3 is shown the dependenceof X on the velocity of the naked projectile (C 6+-ions) expressed in VI jV 0, where V 1 and V 0
are the velocities of the projectile and target electron, respectively. The quantity X increases
very rapidly with the projectile velocity, showing that at higher energies the K-shell ionization
due to the electron transfer becomes more important.

78

10.---------------------------~

I

I

I

I

•
1.0

0.1

I
I
I

•

Presentwork

Io Halpern &. Law

Fig. 3.
10

The dependence of X on VI/V 0
for C6+ -ions.

The observed disappearance of the projectile charge dependence of the ionization crosssection at higher impact energies (Fig. 2) can be understood, at least qualitatively, as follows .
It is unlikely that probabilities of the K-shell electron transfer to C4+-ions increase more rapidly
at higher energies than those to CM -ions. Alternatively the electron stripping cross sections of
C4+-ions at high energy are considerably larger than K-shell ionization cross sections (by twoorders of magnitude).

Therefore, C4+ -ions easily lose their electrons in the interaction withouter shell electrons of the target atom, for example, in the incoming way of the collision,
resulting in C 5+- or CM -ions which interact with the K-shell electrons of the target in the outgoingway. Then, the difference in the ionizations between C4+- and CM-ion impacts tends to disappear
at higher energies.
Coincidence experiments between the charge-changed projectiles and X-rays would beinteresting and useful to understand the inner-shell ionization phenomena.

References:
1)

J. R. McDonald, L. Winters, M. D. Brown, T. Chiao, and L. D. Ellsworth: Phys. Rev. Lett.,
29, 1291 (1972).

2)

1. R. Mowat, D. 1. Pegg, R. S. Peterson, P. M. Griffin, and 1. A. Sellin: ibid, 29, 1577

(1972).
3)

L. Winters, 1. R. McDonald, M. D. Brown, T. Chiao, L. D. Ellsworth, and E. W. Pettus:
Phys. Rev. A, ~ 1835 (1973).

4)

G. Basbas: Abstract of IX ICPEAC (1975).

5)

A. M. Halpern and 1. Law: Phys. Rev. Lett., 31, 4 (1973).

79

7-2.

A Bragg Crystal Spectrometer

Y. Awaya, Y. Tendow, H. Kumagai,
M. Akiba, T. Katou, and T. Hamada

An on-line Bragg crystal spectrometer has been installed for the study of X-rays induced bycharged particles, especially by heavy ions.

An outline of the spectrometer is described in thisreport.
A commercially available X-ray goniometer was obtained, to which a step-scanning mechanism
was added to order. * The vacuum chamber of the goniometer contains an entrance Soller slit,a plane crystal, a proportional counter with a Soller slit, and a Soller slit for a scintillation
counter which is held by an arm outside the vacuum separated by a Mylar window.
geometrical arrangement is shown in Fig. 1.

The

Measurable Bragg angles (28) are from 0° to 120°for the scintillation counter and from 25° to 150° for the proportional counter.
step-scanning are variable at 0.01 0, 0.02°, 0.05°, and 0.1 0.

Intervals of

The standard size of Soller slits(length X blade-spacing) is 10 cm X 0.45 mm for the entrance collimator, 10 cm X 0.15 mm
for the scintillation counter, and 3 cm X 0.45 mm for the proportional counter.

The gas flow,side window proportional counter was commercially obtained, whereas the scintillation counter
with a noise rejector was devised and prepared by one of the authors.
Sc intill atio n Cou nte r

Fig. 1.

Schematic view of thegoniometer assembly.

Fig. 2.

Picture of the target chamber
and the goniometer.

* Rigaku Corp., Cat No. 3122Bl from which a chamber for specimen was taken off.

80

A target chamber, a step-scan-control system, and a system of data accumulation were
designed and made in this laboratory. The target chamber has two windows besides a port to
the goniometer.

One is usually used for viewing the target, while the other is covered with a BE

foil and an X-ray tube is set outside this window.

The characteristic X-rays of target element

induced by photons from the X-ray tube are used for the alignment of the goniometer.
A picture of the target chamber and the goniometer is shown in Fig. 2.
A block diagram of the spectrometer assembly is shown in Fig. 3. Measurements by stepscanning from 2 () = 0i to Of with interval flO can be repeated automatically.

A four-parameter

multiscaler is designed to record four kinds of information at the same time.

The data arerecorded by a multichannel-pulse-height-analyzer (ND2200) used in a dual parameter mode.
The n-th channel number corresponds to the n-th angle from 0i. When the count of pulses fromthe current integrator reaches a preset value, the step-scan-controller orders the goniometer tostep up the angle and, at the same time, the multiscaler to stop counting and to advance thechannel.

After the detector reaches the next position, a pulse is sent from the goniometer tothe controller to start counting.
A tentative energy resolution of this spectrometer is 22 eV FWHM for the photon-induced
Ti Ka X-ray (4.51 keY) using a Ge (111) crystal and the scintillation counter, and 3.9 eV FWHM
for the photon-induced Al Ka X-ray (1.49 keY) using a EDDT (020) crystal and the proportionalcounter.

An example of Al Ka X-ray spectrum induced by 6-MeV/amu N-ion bombardment
28 ( de g-r ee )

/ 10'
15

E , ,,," = 84;\l c \"
AI

K" "

ray

MCA
( wi thout ADC )ND - 2200

KL'

x

y

K

10

4 - para met er
multi sca le r

145

140

135

s t ep -scancontroll er

goniome t er

::l

o

:..>

K L'
1. 49

Fig. 3.

Block diagram of the spectrometer assembly.

Fig. 4.

The Al Ka X-ray spectrum
induced by 6-MeV /amu N-ions.
Each line is labeled by theelectron vacancies in theinitial state.

L81

measured using the EDDT crystal and the proportional counter is shown in Fig. 4.
to single K-plus multiple L-shell ionization.

Peaks are due

The initial vacancy configurations!) are indicatedabove peaks.
Improvement of the energy resolution is in progress.

Reference
1)

A. R. Knudson, D. J. Nagel, P. G. Burkhalter, and K. L. Dunning: Phys. Rev. Lett., 26,1149 (1971).

82

7-3.

Channeling Experiments with High Energy a-Partie les

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

Channeling effects have hitherto been studied extensively using electrons, positrons, andheavy ions at energies ranging from a few keV to about one hundred MeV.

In case of protonand He ions, such experiments have been performed mostly in the energy region below 10 MeV.
There are various difficulties in the experiments with higher energy particles such as that thecritical angle for channeling effects decreases with increasing energy.

However, if such

experiments are applied to the studies of solid state physics, energy loss, lifetime in nuclear
reactions and so on, they will give useful information. Therefore, as the first step, in thepresent work the channeling effects were investigated on a Ge single crystal by means ofbackscattering with 23 Me Va-particles from the cyclotron.
The assembly consisting of a goniometer for the target, a detector, and a collimator is
illustrated in Fig. 1. The crystal orientation of the target could be changed with respect to thecollimated incident beam by varying the angle () and ¢ which could be reset within the accuracyof ±0.010 and ±0.02°, respectively.

The beam divergence was less than 0.05°. The bombardment
1~r---------------------------------~Ge ( 110)
a-23MeV181

Random

r~
"0

Q;
':;'

~

'~
Ul

10

Solid s tate
detector
Co llima tor

beam

()

Target crystal- -2,300mm- Channe l number

Fig. 1.

The goniometer, detector, andFig. 2.

Energy spectra of a-particles

collimator assembly for back-backscattered from a Ge

scattering experiments.

crystal for the incident beamin random orientation(random spectrum) and in
the < 110> direction(aligned spectrum). Incident
beam: 23 MeV.

83

(110)

1.4

~

!

-~

1.2

I

1.0

"0

·\2~U· ·Q)';;' 0,8
"0
~

N

cd

...0E
z

0.6

•

\•

0.4
0,2
0

•

Fig. 3.

ing yield around the < 110> direction

\t

-0.4

Orientation dependence of backscatterof Ge crystal measured in the energy
region indicated by the symbol 11 I

- 0.2

in Fig. 2.

Ti It angle 8 ( degrees )zone was 0.8 mm 2 and the beam current was 2 - 3 nA.

The backscattered a-particles were

measured by a solid state detector placed at a scattering angle of about 1500 and energyanalyzed with a 1024-channel pulse-height-analyzer.

Figure 2 shows the energy spectrum of

a-particles backscatten~d from the Ge crystal when the crystal was oriented in random orientationand that obtained when it was aligned in the <110> direction to the incident beam.

Figure 3

illustrates the orientation dependence of scattering yield X around the <110> direction, which
was measured in the energy region indicated by the symbol 111 in Fig. 2 and normalized to thevalue for random orientation.

Strong attenuation was observed when the beam enters the crystal

within a small angle to the <110> direction, i. e., axial channeling.
dependence was measured around {II O} planar direction.

Similar orientation

The critical angle l/Il/2 and thenormalized minimum yield Xmin for <110> axial and { 110} planar channeling were obtained
from the extrapolation of the observed values to the crystal surface.

They are listed in Table 1.

Barrett made detailed Monte Carlo calculations and derived empirical formulas for l/Il/2 andXmin except Xmin for planar channeling. 1)

These formulas fitted well a great variety of. experimental values obtained in the energy region below lOMe V.
these formulas were also listed in Table 1.

The values calculated from

Since the energy dependence of Xmin for { 110 }planar channeling can be considered to be weak, it might be compared with 0.23 obtained from
Table 1.

The critical angle l/Il/2 and the normalized minimum yield Xminfor <110> axial and { 110} planar channeling.
l/Il/2 (calc.)

<110>

0.18

± 0.05°{ 110}

0.071 ± 0.004°

Xmin (obs.)

Xmin (calc.)

0.020 ± 0.004

0.025

0.20 ± 0.02

84

the experiment with 1.5 MeV proton. 2 ) We can see from Table 1 that there exists good
agreement between the experimental results obtained from the present work and the calculated
values from Barrett formulas.

References
1)

J. H. Barrett: Phys. Rev., B3, 1527 (1971).

2)

K. Morita and N. Itoh: J. Phys. Soc. Japan, 30, 1430 (1971)

85

7-4.

Positron Annihilation In Aluminum

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

The angular distribution of two photons resulted from annihilation of positrons in aluminum
single crystals has been studied with a parallel-slit system. The experimental results shown in
Figs. I and 2 reveal small but definite crystalline anisotropies of the electron momentum
distribution in aluminum. It has been believed for a long time that the valence electrons inaluminum are nearly-free and therefore the angular distribution curves are almost isotropic andIndeed, the early experiments by Berko and Plaskett 1 ) and theoreticalhave a parabolic shape.

calculations by Stroud and Ehrenreich 2 ) have failed to find these crystalline anisotropies.
Recently, Kubo et al. 3 ) have made very elaborate theoretical calculations of the angular
distribution curves for aluminum. Their results are also shown in Figs. 1 and 2. The agreement
between the experiment and theory is remarkable.

I

...

~

2.0

Angular'.'.".

distribution

.....

'.'.

'\.

Anisotropy
Experiment

0.06

Theory

<1.l
4-'

0>
C

+'
c:
::::J

o
u

1.0

0.04

0
\...

'.

~

.....

( 111) - (110)
Experiment
Theory

•

0'>

c

\

4-'

co

::::J

0
U

co

002/1
..

<1.l

I

•

U

co

\

<1.l

\...

0

~..

~.~I.

.....<1.l

\

~

•

0

\

.

• 2.0
~

Momentum in A.U.

-0.02

\

t..•-.r..:;;...;;.;;.;-;.t-r;:-,._ _O~------------~--------~·~·~~,·

1.0

MomentumFig. 1.

2.0

in

-0.04

A.U.

Measured angular distribution ofFig. 2.

Anisotropy, i.e., the difference

two photons from positronin counting rate between theannihilation in aluminum along

angular distributions along the[111] direction; errors are[111] and [110] direction.

smaller than the size of the points.

Typical error bars are indicated.

The theoretical curve is taken

The theoretical curve is takenfrom Ref. 3.

from Ref. 3.

86

References
1)

S. Berko and J. S. Plaskett: Phys. Rev. , ~ 1877 (1958).

2)

D. Stroud and H. Ehrenreich: ibid. , l2.1. 399 (1968).

3)

Y. Kubo, S. Wakoh, and J. Yamashita: Private communication.

87

7-5.

Mossbauer Effect of61

Ni In Various Magnetic Oxides
and Sulfides
H. Sekizawa, T. Okada, and F. Ambe

Mossbauer effect of the 67.4 keY Y line of 61 Ni was utilized in investigating magnetic
compounds containing nickel through the measurement of magnetic hyperfine fields, and a partof the results has already been published. 1)
The Y-ray source is prepared as follows: A Ni-V alloy disk of about 20 mm in diameter isirradiated with 21 MeV ex-particles from the cyclotron and 61CU is produced by the following
reactions, 58Ni(ex, p) 61 CU and 58Ni(ex, n)61Zn @+, EC
61CU. Disintegration of 61CU with a7?

half-life of 3.3 h yields the 67.4 keY isomer in 61Ni. The disk is utilized as a Mossbauer source
without chemical separation. The Mossbauer spectrometer is a conventional one driven in
constant acceleration mode. The source is kept at liquid nitrogen temperature to increase therecoilless emission fraction. The spectra obtained were analyzed by least squares fitting. As theanalysis is still going on, only a preliminary description of the results obtained at the liquid
helium temperature will be given below.
As has been reported previously, the oxides with octahedral nickel ions such as NiFe204,
NiC0 20 4 , and NiMn204 all showed spectra indicating the presence of a hyperfine field of
several tens of kOe, while an oxide with tetrahedral nickel ions NiCr204 gave a spectrum withan extraordinarily large field of 450 kOe, so that an investigation of its origin seems very
interesting. I) By replacing half of the nickel ions in NiCr204 by manganese ions, that is, inNio.s Mno.s Cr2 0 4 , it was found that the hyperfine field decreased rapidly to a value comparable
to the values in other magnetic oxides. The hyperfine field in an isomorphous antiferromagnetic
oxide NiRh 20 4 was found to be very small, and the effect of the electric field gradient was
rather dominating, reflecting the J ahn-Teller distortion of the crystal. Numbers of magnetic.. ..

...... ,:.. --'-......:~~.:,.,..
":;.',••
100 OOeo(\ -.- .. .. . . . . .:. ..
.. .....
.
.

r_....... .,,~. • •••'A,.......:;,•• ,. .. , ......

. .
~......
.
r.",.·,-,.....: . -.-:.... .. .
..,::.~• ,I. .... - ••• •• .......

~,:':/'I!..,~.".-"

..
.\:

"' ..

..

.

....... ..

.,... ,.

I.

.,>.....:,,:..,.

'::. •••'7.-

Fig. 1.

96.00rII- 10

The Mossbauer spectrumof 61Ni in Nio.4Cuo.6Cr2S4IoVelocity in

10
mm/s

taken at liquid heliumtemperature.

88oxides containing nickel ions in the octahedral site such as Ni2 Ge0 4 with spinel structure,
Nio.ssLio.4s0 with rock-salt structure, and Y3Fe3NiGe012 with garnet structure all showedsimilar ordinary values of hyperfine magnetic field of several tens of kOe. CuCr2 S4 is aferromagnetic cha1cogenide spinel in which the copper ions occupy the tetrahedral site. A
specimen Ni o.4 Cu o.6 Cr2S4 was prepared in replacing Cu by Ni in CuCr204 and the Mossbauer
spectra were taken on it. An example is shown in Fig. 1.

As can be seen, the hyperfine field

is not high, amounting to only 76 kOe.
These results established the peculiarity of the electronic state of Ni ions in NiCr204.

ReferenceI)

H. Sekizawa, T. Okada, and F. Ambe: 1. phys. (Paris), 32, CI-326 (1971).

89

8. RADIOCHEMISTRY AND NUClER CHEMISTRY

8-1.

Mossbauer Emission Studies of Defect Atoms in Solid
after N uc lear Decay and Reaction

F. Ambe and S. Ambe

The 119Sn-Mossbauer emission studies of defect atoms in solid1) - 8) have been continued on
119 Sb and 119m Te produced by proton and a-reactions in SnSb and SnTe. Comparative studies
have also been begun on 121 Sb after the 13--decay of 121m Sn,9) which may be regarded as a
mirror image system of the hitherto-studied one, 119Sb K 119 Sn.
In a preceding report,10) we showed that the final lattice position of the recoil 119Sb atoms
produced by proton reactions in SnSb and SnTe can be determined from the isomer shift oftheir daughter, 119Sn, since the recoil energy accompanying the EC decay of 119Sb is muchsmaller than the minimum displacement energy of atoms in solid.

In this way, the recoil 119Sb

atoms were found to be distributed between the Sn- and Te-sites after proton reactions in SnTe.
The effect of thermal annealing on the recoil 119Sb atoms in SnTe has been studied.

100

--

The

' ,

100
( a)

(a)

92
>-Vi
c:

..... 96

>-

1

100

.....
'"c:

0
Q)

a:

'">

(b)

'">

0

94

'" 100
a:

--

100

"

( b)

96

(c)

92

-4

a
Re lativ e velocity

Fig. 1.

8

4(mm /svs- 4

119 Sn-Mossbauer emission spectra of
proton-irradiated 120SnTe.

(a) Noannealing, (b) annealed at 500°C for
1 h, and (c) annealed at 600°C for 1 h.

aRelative vela ci ty

Ba Sn0 3 at 78K)

Fig. 2.

8

4(mm / s vsBaSnO;,

at

78K )119Sn-Mossbauer emission spectraof a-irradiated (a) 117SnSb and(b) 1l7SnTe.

90

proton-irradiated 12°SnTe samples were heated at constant temperatures in argon atmosphere , andthe variation of the 119Sn-Mossbauer emission spectra was followed.
in Fig. 1.

Typical examples are shown

The spectra show that the 119Sb atoms in the Te-site are transferred to the Sn-sitein the thermal annealing process.

This may be interpreted on the basis of the fact that theelectronegativity of antimony is much closer to tin than to tellurium.
The fate of recoil 119m Te after ~-reactions was also studied in the SnSb and SnTe matrices.
The 117SnSb and 117SnTe samples 17 Sn: 117Sn 84.23 %, 119Sn 1.24 %) were irradiated withe

32 Me V ~-particles in a target box filled with helium gas.

The results are shown in Fig. 2.

From the energy of ~-particles and the isotopic composition of the samples, it is evident thatthe dominant nuclear reaction leading to 119mTe is the 117Sn (~ , 2n) 11 9mTe reaction.

Thus, weobserve here the Mossbauer emission spectra of 119Sn following the sequence of nuclear processes:
117Sn (~, 2n) 11 9mTe ~ 119Sb ~ 119S n . As the recoil energy associated with the EC decay of
119 mTe to 119Sb is of the same order of magnitude as the displacement energy , it cannot be
assured a priori whether or not the observed lattice site of 119Sn is the same as the final positionof 119m Te after the recoil due to the ~-reactions.

However, the measurements on SnTe andSb 2 Te 3 samples labeled with 119mTe show that the dominant emission lines correspond to 11 9Sn
in the Te-site of the compounds, the subsidiary ones being attributable to the other site. 10 )Therefore, we assume that the emission line of the ~-irradiated I17SnSb (Fig. 2 (a)) with anisomer shift of 2.42 mm/s (vs BaSn0 3 at 78 K) corresponds to 119Sn arising from the recoil
119mTe atoms which have corne to rest at the Sb-site of 117SnSb.
~-irradiated

The emission spectra of

I17SnTe were composed of two lines with isomer shifts of 2.27 and 3.2 mm/sec ,which are assignable to the 119Sn atoms in the Te- and Sn-sites respectively (Fig. 2 (b)).

Thewhole shape of the spectra is quite similar to that of the labeled compound source, Snl19mTe.l0)
Therefore, we conclude that all the recoil 119mTe atoms were stabilized at the Te-site after the~-reactions,the 119Sn in the Sn-site being considered to have resulted from the recoil

accompanying the EC decay of 119mTe to 119Sb.
Studies of SnTe samples deviating slightly from the stoichiometry are in progress.
References
1)

F. Ambe, H. Shoji, S. Ambe, M. Takeda , and N. Saito: Chem . Phys. Lett., 14,522 (1972).

2)

S. Ambe , F. Ambe, and N. Saito: Radiochim. Acta , ~ 121 (1973).

3)

F. Ambe and S. Ambe: Phys. Lett. , 43A, 399 (1973).

4)

F. Ambe , S. Ambe, and H. Shoji: Radiochem. Radioanal. Lett. , ) 5..2. 349 (1973).

5)

S. Ambe and F. Ambe: Radiochim. Acta, 20, 141 (1973).

6)

F. Ambe , S. Ambe , H. Shoji, and N. Saito: J. Chem . Phys., 60 ~ 3773 (1974).

7)

F. Ambe and S. Ambe: Bull. Chern. Soc. Japan, 47, 2875 (1974).

8)

S. Ambe and F. Ambe: Inorg. Nucl. Chern. Lett., l.h 139 (1975).

9)

S. Ambe and F. Ambe: J. Chern. Phys., 63, 4077 (1975).

10)

F. Ambe and S. Ambe: IPCR Cyclotron Progr. Rep. , ~ 108 (1974).

91

9.

RADIATION CHEMISTRY AND RADIATION BIOLOGY

9-1.

Heavy-Ion Radiolysis of liquid
Isobutyra Idehyde

M. Matsui and M. Imamura

In a previous stud y l) of the heavy-ion radiolysis of liquid aliphatic ketones, the thermal
decomposition of free radicals (thermal-spike effect) was assumed to take place in the high-LET
track cores; this effect gives rise to a marked increase in the yields of H2 and CO as well as in
G (H 2 )/G (CO) in the high-LET region.
A similar thermal-spike effect has also been observed for the heavy-ion (C and N ions;o

LET = 34 - 76 eV A-I) radiolysis of liquid isobutyraldehyde.
Major gaseous products are H2 , CO, C3 H s , and C 3 H 6 , the yields of which were determinedby gas-chromatography.

The yields of H2 and CO were observed to increase steadily with anincrease in LET as in the case of other liquid organic compounds examined.
yields of these two products also shows an increase with LET.

The ratio of the

These results are qualitatively

similar to those for liquid ketones and may be explained by decomposition of free radicals in
the high-LET track cores.
Another noteworthy result is an unusual increase in the yield of C 3 Hs . Propane was notdetected from isobutyraldehyde irradiated with low doses and at low dose-rate.

However, C 3 Hs

is produced by prolonged irradiation; the dose dependence is shown in Fig. 1.

In addition, theinduction period for C 3 Hs formation diminishes with an increase in dose rate and its yield shows

o

200

f

I

100

o
o

\

~

o

·---r·-=----~----~~----~~----~5~----~6----~

Dose A 10-19/ e V

Fig. 1.

N-ion radiolysis of isobutyraldehyde.
dependence of G(C3HS).

Dose and dose-rate., 0.4 - 1.2 nA; 0, 2.7 - 6.7 nA.

92

a steep increase.

The yield reaches 230, about 20 times as large as that of C 3 H6 .

This result

suggests that C3 Hs is formed by a chain mechanism.
As demonstrated in 'Y-radiolysis,2) the telomer formation may also be expected in theheavy-ion radiolysis of isobutyraldehyde at the early stage where C 3 H6 is produced.

The

accumulated telomer will then be radiolyzed (Reaction I), and the chain mechanism may be
explained in terms of a series of Reactions 2 Telomer -

-

-7
7

5.

C3 H7 . + RCO·

(1)

(2)
C3 H7 •

C3 /f.

7C/fO C3HS

+ CH 2 (CH 3 )CHCHO

CH 2 (CH 3 )CHCHO ~ C3H6C 3 H6+ HCO·+ C 3H7 O· - - - - - 7 Telomer

(3)

(4)
(5)

References
1)

M. Matsui and M. Imamura: Bull. Chern. Soc. Japan, 47, 1113 (1974).

2)

C. E. Stoops and C. L. Furrow: J. Org. Chern., 26, 3264 (1961).

93

9-2.

Emission Spectra of Alkali Halides under Heavy-Ion
Irradiation at 4.2K

K. Kimura and M. Imamura

Ionizing radiations densely produce excited states, ions, and free radicals along their tracks
in condensed matter.

Interactions among these species, which exert substantial effects on the

succeeding processes, are expected to be pronounced in heavy-ion irradiation than in X- or
Y -irradiation.

Information on the interactions within radiation tracks could be obtained by measuring
emission spectra or ESR spectra in some cases more directly than by other analytical methods.
This report presents preliminary results on emission spectra of a KBr single crystal under Heand C-ion irradiation at 4.2 K.

The results of ESR have been reported previously. 1)

Two intrinsic emission bands at 280 and 545 nm from Y-irradiated KBr have been assigned
to the transitions from a singlet exciton , 1 ~u ~ 1 ~g, and from a triplet exciton, 3~U ~ 1 ~g ,respectively; the principal color centers formed at 4.2 K are F and H.
A single crystal of KBr was subjected to irradiation with 25-MeV He-ions and 85-MeV

C-ions at 4.2 K, and emission spectra were recorded as shown in Fig. 1.
In comparison with the spectrum for Y irradiation, the bandwidth is broader by 0.07 eV
for He-ion and by 0.18 e V for C-ion than that for Y -irradiated KBr. This broadening is presumably
due to a superposition of the states split by the interaction between excitons densely formed byheavy-ion irradiation.
The ratio of emission intensity of the singlet exciton to that of the triplet exciton for Heand C-ion irradiation is 2 - 3 times the ratio for Y irradiation.

This result is puzzling in viewof the fact that the rate of radiationless relaxation of the singlet exciton increases withincreasing temperature more rapidly than that of the triplet exciton does, because the temperature
Waveleng th( nm I

T , He, C

Fig. 1.

Emission spectra of KBr underirradiation of ,),-rays, He-, andC-ions at 4.2 K.

Intensities

are normalized at 280 nm. The
values in parentheses show
halfwid ths in eV.
Energy (eVI94

of heavy-ion tracks must be higher.
Prolonged irradiation or irradiation at high dose rates results in decrease in the intensity
ratio and shift of the emission band of the triplet exciton to shorter wavelengths, as shown in
Table 1.

The spectra obtained cannot be ascribed to known color centers. These results

suggest the formation of other color centers under these irradiation conditions or the
deformation of the wavefunction of the triplet exciton due to dense formation of the color
center.

Table 1.
Dose (nA)

Ratio of emission intensities, 1280/1510.
Dose (nC)

1280/ 1510

6

0.58
4.8

2200

7

0.3

3600

3

0.76

3840

3

1.1

4040

3

Reference
1)

K. Kimura, M. Ogawa, M. Matsui, T. Karasawa, M. Imamura, Y. Tabata, and K. Oshima:
J. Chern. Phys~, 63, 1797 (1975); IPCR Cyclotron Progr. Rep., b 120 (1974).

95

9-3.

Inactivation of Bacterial Cells with Different DNA Repair
Capacity by He-, C-, and N-Ions

F. Yatagai, T. Takahashi, and A. Matsuyama

Many investigators have presented evidence for that DNA is an important target for theaction of charged-particle radiation in affecting the viability of bacterial cells and that the efficiencyof their DNA repair largely influences the cellular radiosensitivity.

Therefore, it becomes

important to determine the LET dependence of repair capacity for DNA lesions in order toelucidate theLET effect on bacterial cells.

E. coli k-12 AB 1157 (rec+), AB 2470 (recB), and JC 1553 (recA) were bombarded witha-particles, C-ions, and N-ions from the cyclotron.

These strains have already been known to havelargely different repair capacity for DNA lesions caused by UV or X-irradiation.

The preparationof bacterial cells and dosimetry were made in the same way as previously described. 1)
All survival curves of these strains determined by the visible-colony counting method show
an exponential type for the cyclotron beams as well as for 60Co 'Y-rays. The values of I/D 37
for 60Co 'Y-rays were found to be those in Table 2, and the decrease in I/D 37 with increase of
LET 00 was observed with all these strains bombarded by the cyclotron beams.

As can be seenin Fig. 1, the I/D37 values for recA were found to be almost the same as those for recB in
the LEToo region greater than""" 30 keV/}1m (a-particles).

The difference in I/D 37 values between

the rec+ wild type and the above two mutants diminishes as the LET 00 of bombarding particles
is increased.
Radiation sensitivity can also be expressed as an effective inactivation cross section, Seff.
Figure 2 shows the experimental results that Seff for each strain increases with increasing LEToo
Table 1.

Values of best-fit parameters in Eqn. ( 1) determined by themethod of least-squares.

StrainSo (}1m 2 ).e (nm)j0

Wo (keV)

X2

rec+

0.367

0.287

I

1.0

0.193

recB

0.557

2.23

2

1.0

0.0650

recA

0.549

2.42

2

1.0

0.397

Table 2.

Values of best-fit parameters in Eqn. (2) determined by the method ofleast-squares.

StrainSo (}1m 2 ).e (nm)jo

Wo (keV)

X2

rec+

0.560

5.53

2

1.0

0.654

5.01 X 10- 3

recB

0.560

6.16

2

1.0

0.105

recA

0.560

6.06

2

1.0

0.496

b(llm/keV)l-£-bL(y -rays)

1/D 37 (krad- 1 )(Y-rays)
8.4 7X 10-2 (1.0)

3.12X 10-2

1.00X 10- 3 (1.0)
6.24X 10- 3 (6.2)

3.47X 10-2

6.94X 10- 3 (6.9)

7.7 5 X 10- 1 (9. 1)

5 .1 8 X 10- 1 (6.1)

96

9.0

8

B.O
r ecA
8

recB
®

a - parti c les :•0

C - ion s

...

f':,

N - ion s•

0

6OCo Y- ra ys

7.0

:'..3
(J)

6.0

®

~

(J)

g

'" 5.0

~

OJ
;..

•

'" 4.0

OJ

o

0::

•

•
o
o

o

•

3.0

Fig. 1.

2.0

Relative radiation sensitivitiesof the mutants, recA and recB

1.0

,

<

!

I

20

50

!

!

I

!

I

!

100
L ET ,

200

I

!

!

!

500

!

to those of the wild type

I

1,000

strain, rec+ (see text).

( keV/ ,um )of a-particles and that heavier charged particles give higher values of Seff at the same beamenergy per nucleon.

However, changes in the beam energy or LET00 on C- or N-ions do notlargely vary the values of Seff except in the case of recA strain.
An attempt was made to interpret the characteristic LET dependence by the target theory
based on the microdose concept proposed by Oda et al. 2)

According to the theory, Seff isexpressed as the sum of the effects of the track core (S~ff) and o-rays (Sgff)'where

c_ (iZLw <wo ) )f J' -

•

J !

(

)

exp - iZLw <wo , andc! - (iZLw• >wo )J exp (-()L
)
~
W>Wo·

fJ -

J !

The quantity So is the geometrical cross section of the target, .e the thickness of the target, W
the pnmary activation energy (35 eV), jo the critical number of primary activations, Lw < wothe track core LET, Lw >wo the local LET of the secondary electron, and Wo the cutoff energy
for o-rays.
Calculation was made by the method of least-squares to fit the experimental data using
Eqn. (I).

The best-fit parameters are summarized in Table I, and the theoretical curves

including these parameters are shown in Fig. 2.

Since the target size is expressed by the valuesof So and £, the three strains used here should have almost the same values for these twoparameters.

However, the calculation with these three strains gives different values of So and .e

as shown in Table 1. This result may suggest that So and .e are affected by the DNA repair
capacity characteristic of each strain.

97

a- pa r ticl es : 0

5X10S2

2X10S ·2

C - ions: £;N - ions:0~

re C+( S =-3 )/
//. 0

~:I
/

1X10S · 2

5XIO S · 1

r ecB ( S = - 2 )/ / .

E

::t.

-

/~

'/

u)

2XlOS2

Fig. 2.
1XIOS'

1for three strains.

recA ( S =- 1)

5XlOS

/

theoretical curves for eachkind of charged particles
calculated from Eqns. (2)

2X10S
20

Solid andbroken lines show the,,//

LET dependence of Seffand (1) respectively (see200text).

L E T..~ ( ke V/ j1m )Then, an analytical method to give almost the same target size to these strains by introducing
a term of DNA repair capacity to Eqn. (1) was applied for the bacterial system like this.
Parameter of DNA repair capacity , b, is defined to express the probability that the initial damageis repaired as exp (- bL).

Since (1 - exp (-bL)) gives the probability that initial damage

becomes lethal, Eqn. (1) can be modified as follows:

Figure 2 also shows that the theoretical curves which were calculated from Eqn. (2) using theparameters in Table 2 explain the experimental data fairly well.

According to the definition ofparameter b, the value of (1 - exp (- bL)) for low LET radiation such as 60 Co ')'-rays might be
expected to reflect the radiation sensitivity of bacterial cells.

As shown in Table 2, these values

for each strain are found not to be contradict with the sensitivity for 60Co ,),-rays as expected.
These results suggest that such an analytical method considering the DNA repair capacity would
be powerful for understanding the LET effect on bacterial inactivation.
References
1)

F. Yatagai, T. Takahashi, Y. Kitajima, and A. Matsuyama: J. Radiat. Res., ~ 90 (1974).

2)

N. Oda, T. Numakunai, and S. Ohtani : Biophys . Aspects of Radia. Quality, IAEA-SM 145/47,
Vienna, 99 (1971).

98

9-4.

Effects of Heavy Ion on the DNA Synthesis In Bacterial Cells

S. Kitayama, F. Yatagai, and A. Matsuyama

We are interested in the difference between radiochemical lesions on DNA induced by low
and high LET radiations. In case of low LET radiation such as 60Co ,),-rays, energy loss events occur
independently each other and radiochemical lesions might be separated on the long DNA strand
at least within low doses of irradiation.

On the contrary, the energy loss events take place along

the track of a heavy ion making ionization column.

Traversal of such track core through thechromosome region in the cell may induce radiochemical lesions on both strand of duplex DNA.
The double strand break of DNA is an example of such lesions and the ratio of double- tosingle-strand scissions increases with increasing LET. I) On irradiation of DNA solution with ,),-rays,
the number of single-strand breaks is approximately 20 times larger than that of the double-strand
breaks.

About 30 % of single-breaks have free 3'-OH terminal and they become a priming site

for DNA polymerase I. 2 )As schematically illustrated in Fig. I, unirradiated duplex DNA is apoor template for DNA polymerase I, since the enzyme requires free 3'-OH and the complementarystrand (Fig. 1 (a)).

Low-LET radiation such as ')'-rays induces many single-strand breaks and someof them have free 3'-OH with the intact complementary strand as shown in Fig. 1 (b).
Subsequently, DNA polymerase I can start DNA synthesis from these sites.

On the other hand,

it would be expected after high LET irradiation that both strands of duplex DNA have radiation

HO~5'- ;:::=============3::..'~OH } native
P 3'

5'P

DNA

5'

3'

polymeraseHO~=============~PP OH
P 3'
5'

3~OH

5
3'
HO ;::;' =====-;:==~P:::=.==~O::;::Hp

i

P 3'

5'
,

5'-P 3'- OHI

P3'

fv'v'\.'\

xx;:::.......o...-5:"-P

_

3'OH

1-OHt

newly synthesized strand.

Fig. 1.

DNA

HI~O-===============~ OH

~,

5'
HO P

polymerase I3'(b)5' _><><
HO3' OH
P 3'\ MMNVVV'VVVV- P

3'
HO_5'--xx _ _O_Hp=====~;XOH
templateDNA

Irradiatedpolymerase I
with heavy Ion(c)

HO~ ~ _ _ _ _
3~H

P3 '
•

base

damage~,P -3'-------x-x-stra ndx x~ 3'-OH~,

scission which termi nal is not free 3'-OH

Schematic representation of priming activity of DNA.

JV\/V' newly synthesized strand.

•

(a)

3'

5'

5'

3'-OH 5:'P

template
Irradiatedwith T-rays

r

3'

~,

5'

P 3'

3'-OH
3' OH }HO 5 p__)(:_P=====-~p
HO 5'

i

template

3 0HHO_
5 '_xx _ _ _ _ _--:::..

P 3''\J'OHHO 5'
P 3'

base damage- x x - strand scission which terminal is not free 3 '- 0 H

99damage at a complementary site, for example, a double-strand break or single-strand break plus
base damage (Fig. I (c)).
I.

DNA which has these damages is a poor template for DNA polymerase

If such explanation is applicable for the inactivation of living cells by radiations, unscheduled

DNA synthesis would be observed clearly after irradiation with low LET radiations, but poorly or
not after the bombardment with high-LET particles.
When the cells which are made permeable to deoxyribonucleoside triphosphate are irradiatedwith "Y-rays, the rate of DNA synthesis is stimulated possibly by the increase in internal 3'-OHtermini in duplex DNA as stated above. 3)- 5) DNA synthesis in the permeable cells ofMicrococcus radiodurans, the preparation of which was recently succeeded in this laboratory,
was found to be stimulated by irradiation with 60CO "Y-rays up to about three fold. Permeable
cells of M. radiodurans is a suitable system for comparing the effect of low and high LET
radiations, because this bacterium is very resistant to radiation and shows a shoulder on its
dose-response curves.

Within shoulder doses the radiation damages should be repaired irrespectiveof the type of damage or of the type of repair system.

In addition to the damage on DNA,a damage on the cell membrane might be plausible after heavy-ion bombardment.

When heavy

ion traversed it, the destruction of the transport barrier of the cell membrane could take place
more or less.

However, intact cells of M. radiodurans (not permeable to dXTP) did notincorporate dXTP into DNA after irradiation of N-ions with a dose which corresponds to several
hundred traversals of heavy ions through the cell membrane (Fig. 2).

Irradiation of the permeable

cells with N-ions stimulated the rate of DNA synthesis similarly to the irradiation with "Y-rays.
The extent of stimulation by N-ions was 2 - 3 fold, which was the same as the stimulationby ,),-rays.

This result indicates that free 3'-OH termini are produced directly or by enzymatic

reaction after irradiation with N-ions, but the complementary strands are intact.
different from the expectation shown in Fig. 1.

This is somewhat

Some explanations would be possible why the

400

en

Q)

~"- 300

Fig. 2.

en

Stimulation of eH)-TTP incorporation
by irradiation with 60Co ')'-rays and

<l>

o
E

N-ions.
Permeable cells (straight line) or intact

-c

~ 200
L.

o
c..
L

:3c:
(L

f-

~ 100

/

./

•

cells (broken line) were irradiated with')'-rays (200 krad) or N-ions (2.9 MeV,
25 nC) and incubated at 37°C in thecomplete reaction mixture for DNA
synthesis.
e-e, unirradiated control; 0 - 0,

irradiated with ')'-rays; ~-~,
Ti me of incubation (min)irradiated with N-ions.

100

experimental results did not coincide with the expectation stated above.

For example, 8-rays

might induce single-strand breaks at a very distant position from the track core on the folded
chromosome in bacterial cells.

An alternative explanation would be that duplex DNA in living

cells is protected from damages produced simultaneously on both complementary strand.

These

possibilities could be studied in more details using charged particles with different LET and thebiochemical system as stated above.

References

1)

R. C. Christensen and C. A. Tobias: Int. J. Radiat. Biol., 22, 457 (1972).

2)

R. B. Kelly, M. Atkinson, J. Huberman, and A. Kornberg: Nature, 224, 495 (1969).

3)

W. E. Masker and P. C. Hanawalt: Proc. Natl. Acad. Sci. U.S.A., 70, 129 (1973).

4)

D. Billen and G. Hellermann: Biochim. Biophys. Acta, 361, 166 (1974).

5)

S. Kitayama and A. Matsuyama: ibid., in press.

101

10. PREPARATION OF RADIOISOTOPES AND LABELED COMPOUNDS

10-1.

Production of Radioisotopes and Preparation of labeled
Compounds for Medical Use

T. Nozaki, S. Ambe, M. Iwamoto, T. Ohsawa,T. Karasawa, M. Okano, Y. Kasida, T. Ido, K. Suzuki,
K. Fukushi, L. Iwata, T. lrie, T. Hara, and K. Taki
The production of 18 F, 43K, and 123 1 has been continued to meet the needs mainly of
medical use. The following process was found to be convenient for the production of 43K:
(1) drench the inside wall of a glass bombardment vessel (6 cm in diameter, 70 cm in length)with dilute phosphoric acid (1 : 4) and keep the vessel standing vertically for several hours;(2) bombard argon streaming slowly (I R/min) in the bombardment vessel with a-particles of
20 - 21 MeV incident energy; (3) set the vessel vertical, joint a reflux condenser and a quartz
flask containing CaC0 3 (I g) and water (20 mR) to the top and the bottom of the vessel,
respectively, and heat the flask strongly with a direct flame for about 10 min; (4) leave theflask to cool and transfer the water in it into a vial through a millipore filter. The water inthe vial contains usually about 90 % of the total 43K formed and is ready for intravenous
injection.
A new cyclotron for producing exclusively lIC, 13N, and IBF will be installed at the
National Nakano Chest Hospital, Tokyo, next year. For the purpose of routine production of
13N2 and carrier-free 13NH3 by this cyclotron, the chemical form of 13N formed by proton
bombardment of water was studied under various conditions, together with possible methods
for its conversion into the desired compounds by remote operation. As for the excitation
function of the 160(p, a)13N reaction, various different curves have been reported. We
re-examined it and obtained a curve agreeing fairly well with that reported by Whitehead. 1)
Studies have been continued on the preparation of 18F-Iabeled compounds and themeasurement of their behavior in mouse. Similarly to 6-fluoro-9-benzylpurine- 18 F
(Compd 1),2) 2-fluoro-9-benzylpurine- 18 F (Compd 2) was synthesized and their behavior invivo was intercompared. The following two differences were found: (I) the C-F bond ofCompd I is ruptured gradually in the animal body, but that of Compd 2 is stable; and (2)a fairly high concentration of Compd 1 is observed in the brain soon after its injection, but
Compd 2 is not accumulated in the brain. The preparation of 8-fluoro-9-benzylpurine is now
under way, though this compound seems to be rather unstable.
By the Schiemann reaction, m- and p-fluorophenyl-alanineIBF

were synthesized and their distribution in mouse and rat

after intravenous injection was measured. The effect of priorinjection of some hormones on their distribution is now underFig. 1.

Purine molecule.

102

examination.
We intend to obtain 19-halogenocholesterol and 6-halogenomethyl-19-norcholesterol labeledwith various radio-halogens in order to compare the effect of substitution with different halogen
atoms on the behavior of substituted steroids in vivo. The preparation of the labeled compounds
is now under study; a mixture of the labeled products will be injected into animals.
The synthesis of selenomethionine-72,73Se was achieved by a pure chemical method.
Biosynthesis, however, is regarded as clearly superior to this method especially for the
preparation in optically active state, and is now being attempted. Since 72Se and 73Se decay
into radio-arsenic, the labeled selenomethionine would be an interesting compound for the studyof the behavior of radio-arsenic formed in vivo.

References
1)A. B. Whitehead and J. S. Foster: Can. J. Phys., 36, 1276 (1958).

2)

T. Nozaki, Y. Ohtsuka, A. Tahara, S. Ambe, T. Ido, K. Fukushi, and Y. Kasida:
IPCR Cyclotron Progr. Rep., L.. 129 (1973).

103

11 . RADIATION MON ITORING

11-1.

Gamma-Ray Exposure from eye lotron
Operation at the Monitoring Station

T. Hamada, M. Okano, M. Nishida, and I. Sakamoto

Measurements of gamma-ray exposure have been continued at the monitoring station built at
a location ca. 85 m SSE from the cyclotron by using a scintillation detector with a speciallydesigned shield for energy compensation. 1)
The small contribution of the cyclotron to the exposure was identified and separated fromothers on the pattern of continuous monitoring data by taking the meteorological record and themachine operation record into consideration.

Actually, a number of short-term increases in 15

minutes' counts of the detector were able to be correlated with conditions of machine operation,and the speed and direction of wind, and decided to be the contribution of the cyclotron.
The incremental values above the fairly constant background were summed for each machine
operation and converted into exposure dose.

Table 1 shows the result of such analysis based on

the monitoring data during the period from 1970 to 1973, which yielded the annual dose ofca. 30 ,uR.
A major dose contribution was found to be due to 18F production for medical use wherea part of the beam passes through free air and produces radioactive gases such as 13N and 15 0.
In early 1973 the target system in the 18 F production was improved so that no radioactive
gases were produced in the atmosphere.

Since then no significant short-term increase of

exposure from cyclotron has been observed until Oct. 1975.

Reference
1)

T. Hamada, M. Okano, and M. Ota: IPCR Cyclotron Progr. Rep., lz. 81 (1967).

104

Table 1.

Date

Gamma ray dose at the monitoring station due to cyclotron operations.

Time

Wind
directions(h)Speeds(m/s)

Integrated
doses(I1 R )

Machine operations
Time
(h)

Subjects

Accelerated
particles

9.4

1970
4/24

0.5 - 096.4

21 - 09

RC

d

7/23

3 - 06

1.0

18 - 05

RC

d

10/29

10- 142.0

09 - 14Fh

0.9

09 - 14

F

h

1971

35.6

N

2/ 3

10 - 14

2/8

09 - 15

1.8

09 - 14Fh

2/9

17 - 220.8

16 - 22

RC

P

3/17

09 - 160.1

07 - 12

F

h

5/25

09 - 17

NW - E0-3

1.2

08 - 13

F

h

6/ 21

10 - 14

NW - NNW

1- 3

4.1

09 - 13

F

h

7/15

09 - 15

N

1- 3

2.2

09 - 14

F

h

10/1

14 - 19

NW

1- 5

3.5

12 - 18

F

h*

11/4

10 - 14

NNW

1- 6

5.2

09 - 13

RC

h

11/10

10 - 15

NNW - ENE

0-3

4.7

09 - 13

Rt

h

11/30

16 - 06

NW - W

8-0

3.5

09 -

NP

d

12/1

19 - 24

N - NW

0-2

3.4

15 - 21

RC

h

12/8

11 - 16

W - N - NE

0-5

4.1

09 - 15

RC

h

1972

30.5

4 - 102.7

09 - 15RCh

N-W-SW-NW

2-4-1-8

3.3

09 - 18RCh

21 - 24

N - NW

3-4

1.6

16 - 24

RC

p

5/30

12-21

NW

1- 5

5.4

09 - 21

RC

p

7/12

0-08

NNW-NW

0-3

2.7

0-08

RC

p *

7/31

12 - 15

N-E

1- 6

1.0

09 - 15

RC

h

12/12

02 - 07

NW?

0-2

8.8

08 - 11

F

h

12/15

05 - 08

W - NW0-2

0.2

06 - 10

F

h

12/26

11 - 13

NNW - NE

0-3

1.8

09 - 15

RC

p

12/27

14 - 16

N - E-S-SW

0-2

3.0

09 - 22RI

2/ 22

13 - 16NNW

2/24

11 - 18

4/18

1973

3.0

2/8

14 - 17NNW

12 - 3

1.1

12 - 16RC

3/14

14 - 17NNW

4 - 15

1.9

09 -

NP

RC:

h

radiochemistry , F: F-18 production, NP: nuclear physics, RI: radioisotope production.

p: proton, d: deutron, h: helium-3, a: helium-4.

* Include rainfall

105

11 -2.

Routine Monitoring

K. Koda, I. Sakamoto, and I. Usuba

Results of routine monitoring on the cyclotron from April 1973 to March 1974 aredescribed.
No remarkable change in leakage radiation and residual activities was observed during thisperiod.
(1)

Surface and air contamination

The surface contamination of the floor of cyclotron room, where the highest level ofcontamination had usually been detected in the cyclotron building, has been kept as low as about
10- 7 IlCi/ cm 2 , owing to wiping-off of the floor twice a year.
When the accelerating chamber was opened, slight contamination of the air in the cyclotronroom was observed. The value of radioactive concentration (beta-gamma) was 10- 12 IlCi/cm3.
Tritium still remained in the accelerating chamber since the last triton acceleration in
December 1970. On the inner surface of the accelerating chamber a contamination of 10-3
10-4 IlCi/cm2 of tritium and 10- 5 - 10- 6 IlCi/cm 2 of other beta- and gamma-emitters was found.
The tritium concentration of the air in the chamber ranges 10-4

10-5 IlCi/cm 3 . Before-

overhauling work begins the air in the chamber is removed completely.

Afterward, aircontamination is not found in the cyclotron room.
(2)

Drainage

The concentration of radioactivities in the drain water of the cyclotron building was foundTable 1.

Annual exposure dose distribution and average dose for the workers from1967 to 1974.
(Dose accumulated from April to next March)

Yearof workers

1967
1968

42
46

1969

Average dose per

Dose distribution (mrem)

Total number

Undetectable

10

101
2

301

2

100

300

1000

person(mrem)

7

212
507

?

>1000

9
8

15
13

8
18

46

9
0
0

11

17

16

2

318

1970
1971
1972

49
50
47

0
7
10

19
15
17

12
15
12

15
12
7

3
1
1

299
261
199

1973

48

14

11

1

0

79

1974

52

30

22
18

3

1

0

32

106

to be of the order of 10-7 IlCi/ cm 3 •The total quantity of activities in the aqueous release in this period was about 24 IlCi,
and the radioisotopes found by the gamma-ray spectrometry were mainly 58CO and 60Co.
(3) Personnel monitoring
Since the enforcement of the rule in 1973 that enough interval for "cooling" should betaken before entering the cyclotron room after deuteron acceleration, the exposure of theworkers to radiation decreased remarkably as shown in Table 1. Namely, the average annual
dose per person has been decreased down to 32 mrem as compared to several hundred mrems
for before 1973.
In this period the accumulated dose of external exposure of the cyclotron operators was
850 man-mrem, which was 50.6 % of the accumulated dose of all cyclotron workers, and the
maximum personnel dose was 320 mrem.
by year.

The dose to the cyclotron workers is decreasing year

107

11-3.

Neutron Measurement in the Cyclotron
Room and the Experimental Area

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

The leakage radiation was measured at various points in the cyclotron building when a l3C
target placed in a large experimental area was bombarded with a 3He beam of 30 Me V; the beam
current was 6 - 7 nA.
The flux of fast neutrons and thermal neutrons, was measured by the activation method
using the reactions 32S (n, p)3 2P and 23Na (n, Y ) 24 Na and dose of gamma-rays with gamma-ray
pocket dosimeters, respectively. The minimum levels detected by the above measurements wereabout 120 n/cm 2 sec, 15 n/cm 2 sec, and 0.01 mR/h, respectively.
The neutron dose rate was calculated using the conversion factor given in NBS Handbook
63, and the results are shown in Table 1.
Fast neutrons were predominantly observed at the following points: the septum (No. 1 pointin Table 1), the beam exit of the machine (No.3), and the slit boxes (No. 4 and No.5), andthe flux at these points was larger than that at other points.

The ratio of fast neutron flux tothermal one at the No. 1 point was 1.3, while that at the No. 2 point which was 3 m apartfrom the septum was 0.15.
Table 1.

Neutron fluxes and dose equivalent rates at various points in the cyclotron building.

~{ Flux (n/em 2 sec)

Nf

Dose rate(mrem/h)Nth[ Flux (n/em

2

sec)

6

7

8

1.6X 104 4.0X 10 3

230

**

180

130

7.9X 103

2.9X 103

42

34

24

3.9X 10 3

4.8X 10 3

2.0X 103 2.9X 103

26

37

490

44

15

18

7.3

11

0.1

0.1

1.9

1.3

0.15

8.7

8.0

1.4

4.9

0.26

7

3.8

3

1.6X 104570

4.2X 104

2.9X 10 3

110

1.2X 104

Dose rate(mrem/h)

NdNth
Y

4

2

Radiation

5

740

120

(mR/h)* See the figure shown below,

**

0.4

0.5

Undetectable.

G.L.

Cross section

Ground plan

Basement

9

10

11

0.1

108

11-4.

,\I\easurement of Residual Tritium

S. Fujita and I. Sakamoto

Tritium gas was supplied to the ion source in order to accelerate tritium ions by the cyclotron
in 19701). The residual tritium is decreasing since then, but it is still detected in the air in the
Since the values of these data were dispersing, it was suspected

accelerating chamber (Fig. 1).

that the tritium concentration would vary with time after the vacuum of the chamber was broken.
In summer and winter of 1975, measurements were made on the desorption rate of tritiumfrom the inner surface of the chamber wall during the period of overhauling. Samples of air
were collected in a can in the stem tank at about 20cm inside from the inspection port
adjacent to the accelerating chamber and measured by a collection-type ionization chamber.I}
First sampling was made just after purging the air in the tank and the accelerating chamberby a fan which is permanently equipped for this purpose.

Then sampling was continued

intermittently for 9 days, during which the tank and the chamber were normally closed.

Asshown in Fig. 2, the tritium concentration increases with time and the rate of growth is fasterin summer than in winter; the time required for reaching a maximum permissible concentratior
10- 2
0

0
0

0

50

-

ME 10- 3
~

_

0

u

0

.3-

U 10

0

",::1..

0

c

20

"-

Q

0

2

0

c

0

(l)

0

u

c

8 -4
10

E

0

::J

~

~

o

0

"E 0.5f-0.2

0 .1 ~--::o:'-=-.
2---::0=-=.5--:-----------=------:0----:-::::-::--10::---~20;:---------="50::----;-10'=0-----:::20:-::00'-----=5-'00
TI me

Yea r

Fig. 1.

Monitoring data for tritiumFig. 2.

(h)Increase of tritium concentration

concentration in the accelerat-

with time after purging air in

ing chamber.

the chamber.
data obtained during the periodof Aug. 5-13 , 1975
X

data obtained during the periodof Jan. 9-18, 1975

109

for tritium is only 2 hours in summer compared with 30 hours in winter.

It suggests theeffect of ambient temperature on the desorption rate of tritium from the chamber wall.

Reference

1)

I. Kohno, A. Shimamura, I. Sakamoto, T. Tonuma, S. Takeda, N. Nakanishi, K. Matsuda,

K. Koda , and T. Hamada: IPCR Cyclotron Progr. Rep. , ~ 11 (1970).

110

12. HEAVY ION LINEAR ACCELERATOR PROJECT

12-1.

Status of Constructional Work of the linear
Accelerator in December, 1975

M. Odera

A contract for fabrication of the first cavity was made with the Sumitomo Heavy Industries ,Ltd. The contract also includes construction of drift tubes loaded with quadrupole magnets andthe precise alignment of their axes within the accuracy of 0.1 mm for the full length of thecavity. The resonator will be completed at the factory in March 1976, and installed as soon as
the accelerator building becomes ready to accept it in the next summer, because we wish to
make a radiofrequency power test of the cavity as early as possible , though constructional workof the building will continue, till autumn.
Two quadrupole magnets made at the machine shop of the Institute and the one made by
the Sumitomo Co. are being tested as to the extent of deviation of mechanical and magnetic
axes under the different 1.lanufacturing processes, the maximum field gradient obtainable , fieldharmonics, flood cooling of coils, etc. A final design of the drift tubes will be frozen according
to the results of the tests.
Orders were placed for a 500 kV power supply, an ion source housing at high voltage
potential , an insulated-shaft-driven generator system for supply of power to the terminal and an
accelerating column. They will be installed next summer in the injector room.
A commercially available cryogenic pump having capacity of 5000 .e/sec at high vacuum wasbought and tested. It's operation was found very simple and satisfactory. It is planned to use acryo-pump in parallel with a molecular pump for each cavity.
A synthesized signal generator was purchased together with a wideband solid state amplifier.
The former has a frequency range up to 110 MHz with a stability of 3 X 10-8 /day and thelatter has 50 db gain between 250 kHz and 105 MHz with power rating at 50 W. As a final-stage
power tube, an RCA 4648 tetrode was chosen and a proto-type high power amp lifer chain
system is being constructed. The first unit will be tested and evaluated for a period between
April 1976 and March 1977 to decide a final detailed design of the high power system.

111

12-2.

Status of the Injector System

M. Hemmi and M. Odera

Figure 1 is a plan of the injector system. The high voltage terminal in which a heavy ion
source and its power supply are to be installed has a large floor area to provide for the future
development of the heavy ion accelerator technology. The housing is supported on porcelain
insulators 3.39 m high from the basement floor. The supporting structure is designed to be
sturdy enough against earthquakes up to 0.3 G acceleration in the horizontal direction.
Rating of the high voltage unit is 500 kV and 10 rnA and the stability of voltage is 10-4
against 10 % line voltage change.

A 50 kV A, 50 Hz generator at the high voltage terminal isdriven via a fiberglass reinforced epoxy rod by an alternator at ground potential. Capacity of
the generator is sufficient for ion sources of any type available at present.
A prototype frequency-modulated light communication system between the high voltage
terminal and a local control panel was made. Light is transmitted through thin-fiber light
conductors covered with an opaque insulator. Tuning forks having high Q-values are used todiscriminate the frequency of modulation and to secure high selectivity against error signals suchas corona discharge noise. Figure 2 shows a block diagram of the system.

Top vi e w

S ide view

Door

o
o

o

....

t----

- t -- 4000- - ---i

Po we r Jine

Hm6 . 20'00!

( rnrn )200 V3+50H z
50k VA Ge nerate r
50kVA
Gene rator

Fig. 1.

500k VlOrnAPower s uppJ y

Top and side views of the injector system.

112

Parallel

48 ch syste m[~

Tuning fork~I

T uning f o rk

~ I

l

I.Ell

~

"

0.

o
I

U

::::I ' ~0.0-= ....JT un ing fork

L 48,- - - - - - - ----'-- - - - -- - - T r a n s m i tt e r - - -- -- - - --Seria l-- - - - R ecei v e r - - - - -64c h system

c.

o

-

Fig. 2.

- --- Transmitte r - --- - - - - i { ( ' C ( ' " ("- - - -- - - -Block diagram of the frequency modulated light communication
system.

113

12-3.

Structure of the Drift-Tube Magnet

Y. Miyazawa, T. Inoue, and M. Odera

A coil of a quadrupole magnet in a drift tube made by using the tape coil technique l ) isshown in Fig. 1. Though it looks much simpler than the plate stacking coil reported before,2)careful fabrication procedure and skill are required. Thickness of the copper tape is 0.5 mm andthat of insulator is 0.18 mm. The insulator is made of a glass cloth impregnated with semi-cured
epoxy resin. The coil consists of 52 layers of copper and insulator tape glued and heat-treated.
Holes are machined to accept pole pieces. Etching by a ferric chloride or nitric acid solution
removes metal bits induced by the machining process and bridging the insulator layer. The
effective number of turns is 26. A photograph of the yoke shown in Fig. 2 indicates the pathof cooling liquid cut on the surface. The yoke is inserted into a shell and sealed by electron
beam welding and a coolant flows in the slots to cool the shell heated by radiofrequency loss.
Figure 3 shows an apparatus for circulating Freon 113 through the tube and a heat exchanger
for cooling.

Fig. 1.
Photograph of Berkeley- type tape coil.

Fig. 2.
Photograph of quadrupole magnet yoke.

114

Fig. 3.

Freon-113 circulation system
for flood cooling of the drift
tube magnets.

References
1)

R. M. Main and R. Yourd: Proc. Fourth Intern. Conf. on Magnet Tech., p. 349 (1972).

2)

T. Inoue and M. Odera: IPCR Cyclotron Progr. Rep.,~ 159 (1974).

115

12-4.

Beam Acceptance of the Drift Tube Focusing System

T. Tonuma, F. Yoshida, and M. Odera

In the linac cavities, there are 36 whole length drift tubes and a half length input sectionin which focusing elements are contained.1)

Theoretically, the best beam profile will be obtainedby tuning the exciting current of each quadrupole magnet separately and adopting different axial
length for each magnet in proportion to the length of the drift tube. However, for practical
purposes, it is not necessary to make such fine individual adjustments of exciting current or axial
length of magnet to obtain a well-focused beam tolerable for experiments.

The tuning procedure

may be made much simpler by using the same value for field gradients of several quadrupoles andpermitting excitation of their coils connected in series.

This simplification causes no substantial

loss of beam quality by suitably choosing combination of the quadrupole magnets.

Moreover, anorbit analysis has shown it possible to make the magnets divided into 9 groups and to keep thegeometrical parameters constant in each group.
Figure I shows acceptance and emittance diagrams of the drift tube focusing system designedon the basis of the above method of grouping of currents and magnet dimensions. The solidline represents acceptance and the dotted line emittance of the beam at the entrance of eachcavity. It is assumed that the beam fills completely the acceptance diagram when injected into
X;y ' ( mrad )

:'"

I

,

I 20 I\I

T ank 1

I

I

I

Ix

I
I
I

x;y ' ( mrad )Tank 3

I,--+-=\
i \'-..!(.
I
I

10

I

I

\

\

\
\

I

I

-~-~
-10:
I
I

I
I

- 20 1
,

,

I
I

,,~

x;y ' ( mrad )Tank 6 E xit

10

- 10

Fig. 1.

Acceptance and emittance diagrams for beam at entrance ofcavities. X and Y denote vertical and horizontal directions
respectively.

Lens sequence is vertically focusing and horizontally

defocusing at the entrance of the first cavity.

The solid line

represents acceptance and the dotted line emittance and the twolines coincide in the first tank.

116

the first cavity.

Therefore, the single line of tank 1 has two meanings of acceptance andemittance in the phase diagram.

There are one or two singlet quadrupole magnets between

cavities to transform emittance at the exit of each cavity into a shape fitted to the next cavity's
acceptance.

With this combination of the quadrupoles, a large transparency through the focusing

system for the injected beam can be expected if enough precaution is paid for alignment of the
focusing elements.

Reference
1)

T. Tonuma, F. Yoshida, and M. Odera: IPCR Cyclotron Progr. Rep., ~ 18 (1972);
M. Odera: ibid., ~ 140 (1973);
T. Tonuma, F. Yoshida, and M. Odera: ibid.,L 147 (1973); ibid., ~ 149 (1973); Reports
I.P.C.R., (in Japanese),~ 53 (1975).

117

12-5.

Effect of Misalignment of Focusing Elements on
Beam AcceptanceT. Tonuma, F. Yoshida, and M. Odera
Beam trajectory was computed for various misalignments and probable manufacturing errors.
Figure 1 shows how the acceptance diagrams in the transversal phase space will change when themagnetic axis of focusing elements deviates from the beam axis. Calculation was made assuming
a combined error of several types such as parallel shift in x-and y-directions, tilt of axis, androtation around the symmetry axis of magnets. The detailed explanation of the computation
procedure is given in reference 1. It is found that the coincidence of axis of magnets with thatof acceleration within 0.1 mm for the first cavity is sufficient to guarantee good transparency.
The tolerance in the alignment can be progressively relaxed for down-stream cavities.
x; l( mrod)

x~ y' ( mrod)

20

-

-

~=O

----- :!: 0 .1mm
- - - :!:0.2mm- .:!:0.3mm

Fig. 1.

Calculated beam acceptance of the cavities when the axes offocusing elements deviate from the acceleration axis.

Deviations

are distributed among the quadrupole elements such as to give
maximum change in acceptance values.

Reference
1)

T. Tonuma, F. Yoshida, and M. Odera: Reports I.P.C.R., (in Japanese),.2h 53 (1975).

118

12-6.

Precise ,\I\easurement of the Symmetry Axis of
Quadrupole ,\I\agnetic Field

I. Takeshita, I. Yokoyama, and M. Odera

For alignment of drift tubes it is required to determine to a certain allowable extent theaxis of each quadrupole magnet which is to be installed in a drift tube shell.

Coincidence of

the axis of field with the geometical center of the tube within 50 11m is desirable in order tosecure good transparency of the beam through a combination of many such quadrupoles.
Centering apparatus for this purpose was devised and constructed using a Hall-effect probe.

By

rotating the probe by 180 degrees around the axis of symmetry, exactly the same voltage would
be observed from the Hall element if the axis of rotation coincides with the axis of themagnetic field.
Figure 1 is a photograph of the apparatus.

A magnet to be measured is fixed on a turn-table,

which is an accessory of an instrument-microscope and is provided with a two-dimensional finepositioning mechanism to bring an object on the table in the center of the microscope field.
The mechanism is useful for determination of center of the magnet.

In addition, a guide isprovided on the table to make the center of the magnet automatically coincide closely with theaxis of rotation of the table.

Temperature of the Hall element was kept constant by attachinga thermister on the back of the element which controls a heater to warm air flowing around theprobe.

Figure 2 shows the circuit for measurement.

Reproducibility of reading of Hall voltage was found satisfactory and the center of field

Fig. 1.

Photograph of the magneticfield centering apparatus.

119r ----- - ----

Res ister

ACIOOV

I
I
I

IErrorlamplifier
I

- 15V

R

I
I
I
I
I
L __ __ _ _ _ - -Current stabilizer( l Xl0- 5jOC )

- \SV

- -

- - -

Hall element leadII_

_ _ _ _ _ ..1+15V

Ther mister leadQuadrupole
magnetFig. 2.

Block diagram of measuring
circuit.

can be determined within a few J.1m by a suitable conversion procedure.

By the magnet shownin Fig. 1 the deviation of the field center from that of geometrical symmetry was 9 J.1m in xand 4 J.1m in y-directions. This deviation can be attributed to the remanent field effect caused bya slight asymmetry in the magnetic property of some poles.
earth's magnetism.

The difference is less than the

Such a small asymmetry may be generated by the difference of mechanicalstress that each pole has experienced during machining, or by the difference in stress of bolts
which fix poles to the yoke of magnet.

Since measurements were made at a low field strength,

the effect of remanent field seems more manifest than would be in the real use.

The field of

5 kG is expected in the real use, and the strength at the radius where the probe is placed in
the present measurements was 500 G.

120

13. LIST OF PUBLICATIONS

1) T. Tonuma, F. Yoshida, and M. Odera: "Beam Dynamics of the RIKEN Heavy Ion Linear
Accelarator", Reports I.P.C.R., (in Japanese), ~ 53 (1975).
2) H. Kumagai, M. Okano, and A. Hashizume: "A Simple Data Recorder and Its Applications
to the Radiation Measurement", Reports LP.C.R., (in Japanese), 51, 120 (1975).
3) B. Imanishi, H. Onishi, and O. Tanimura: "The Multi-Step Effects in the 16 0 - 17 0 Elastic
and Inelastic Core-Exchange Scattering", Phys. Lett., 57B, 309 (1975).
4) T. Nomura, K. Hiruta, M. Yoshie, H. Ikezoe, T. Fukuda, and O. Hashimoto: "In-beam aand 'Y-ray Spectroscopy for 216Ra", Phys. Lett., 58B, 273 (1975).
5) T. Motobayashi, L Yamane, Y. Nogami, N. Takahashi, M. Hara,K. Sagara, M. Katoh,
H. Yamashita, and B. Imanishi: "Full Recoil Analysis of the Elastic Scattering of 16 0 on
19F by the Core-Exchange Model", Phys. Lett., 59B, 421 (1975)
6) W. Kutschera, B. A. Brown, H. Ikezoe, G. D. Sprouse, Y. Yamazaki, Y. Yoshida, T. Nomura,and H. Ohnuma: "Lifetimes of the 6+ States in 42Ti and 46Ca and E2 Effective Charges in(1f7/2 )±2Nuclei", Phys. Rev., C12, 813 (1975).
7) N. Bendjaballah, J. Delaunay, T. Nomura, A. Jaffrin, and H. J. Kim: "Shape Transition in
the Yrast Band of S6Fe", Phys. Rev. Lett., (in press).
8) N. Shiotani, T. Okada, T. Mizoguchi, and H. Sekizawa: "Angular Distribution of Positron
Annihilation Radiation in Vanadium and Niobium-Experiment", J. Phys. Soc. Japan, 38,423 (1975).
9) H. Ohnuma, S. Takeda, N. Nakanishi, S. Yamada, M. Sekiguchi, and H. Toyama: "Study ofthe 58Ni(d, t) 57 Ni Reaction at 24 MeV", J. Phys. Soc. Japan, 38, 1557 (1975).
10) K. Kimura, M. Ogawa, M. Matsui, T. Karasawa, M. Imamura, Y. Tabata, and K. Oshima:"ESR Study of the Spatial Distribution of Radicals Trapped in the Heavy Ion-Irradiatedn-Eicosane Single Crystal", 1. Chern. Phys., 63, 1797 (1975).
11) S. Ambe and F. Ambe: "Mossvauer Emission Spectrum of 121 Sb after the B- Decay of

121mSn in SnS2: Nuclear Decay Synthesis of Antimony (V) Sulfide", J. Chern. Phys.,63, 4077 (1975).
12) T. Nozaki, M. Iwamoto, and T. Ido: "Yield of 18F for Various Reactions from Oxygen andNeon", Intern. J. Appl. Radiat. Isotopes, 25, 339 (1974).
13) T. Nozaki, M. Furukawa, S. Kume, and R. Seki: "Production of 28Mg by Triton anda-Particle Induced Reactions", Intern. J. Appl. Radiat. Isotopes, 26, 17 (1975).
14) T. Nozaki, Y. Yatsurugi, and Y. Endo: "Charged Particle Activation Analysis, Studies on
Carbon, Nitrogen and Oxygen Mainly in Semiconductor Silicon", J. Radioanal. Chern.,(in press).
15) F. Yatagai, T. Takahashi, and A. Matsuyama: "Inactivation of Bacterial Cells by Cyclotron
Beam", J. Radiat, Res., 16, 99 (1975).

12116) M. Matsui and M. Imamura: "Radiation Chemical Studies with Cyclotron Beams. IV,
The Effect of Water in the Heavy-Ion Radiolysis of Liquid Acetone" , Bull. Chern. Soc.
Japan, 48, 2346 (1975).
17) H. Shiraishi, H. Sakairi, E. Yagi, T. Karasawa, R. R. Hasiguti, and R. Watanabe: "Growth
Process of Helium Bubbles in Aluminum", Nippon Kinzoku Gakkaishi (in Japanese), 39,
233 (1975).
18) T. Kammuri and T. Kishimoto: "Boson Description of Nuclear Collective Motion (1)",Z. Physik, (in press).
19) T. Nomura: "On the Alpha Decay from the Excited State of Heavy Nuclei", Genshikaku
Kenkyu , 20, 467 (1975).
20) G. B. Hagemann, R. Broda, B. Herskind, M. Ishihara, S. Ogaza, and H. Ryde: "Gamma
Decay after Heavy Ion Reactions Studied by First and Higher Order Multiplicity
Measurements" , Nuc!. Phys. , A245 , 166 (1975).
21) S. Kusuno and T. Wada: "Microscopic Theory for Proton , Deutron, Helion, and Alpha
Scattering from Collective Levels in Doubly Even Spherical Nuclei" , Sci. Papers I.P.C.R.,
69, 147 (1975).
22) T. Motobayashi, I. Kohno, K. Katori, M. Yoshie, T. Ooi, and H. Kamitsubo: "Anomalous
Angular Distribution in the Transition to the SY2 State in 17 0" , Phys. Rev. Lett. , 36, 391(1976).

122(Papers presented at meetings)
1) T. Inamura: "Lifetimes of High Spin Rotational States in 181Ta", Symp. on Structure of

Medium Mass Nuclei and pf-shell Nuclei, Osaka, Jan. 1975, RCNP-P-2 (1975).
2) B. Imanishi: "Coupled Channel Analysis for Elastic and Inelastic Core-Exchange Scattering",
The INS-IPCR Symp. on Cluster Structure of Nuclei and Transfer Reactions Induced by
Heavy-Ions, Tokyo, March (1975).
3) O. Tanimura, H. Ohnishi, and B. Imanishi: "The Coupled Channel Analysis for theCore-Exchange Scattering", The INS-IPCR Symp. on Cluster Structure of Nuclei and Transfer
Reactions Induced by Heavy-Ions, Tokyo, March (1975).
4) T. Motobayashi, I. Yamane, Y. Nogami, N. Takahashi, K. Sagara, M. Mihara, M. Katoh,

H. Yamashita, and B. Imanishi: "Elastic and Inelastic Scattering of 16 0 and 19 F", The
INS-IPCR Symp. on Cluster Structure of Nuclei and Transfer Reactions Induced by
Heavy-Ions, Tokyo, March (1975).
5) B. Imanishi, H. Ohnishi, and O. Tanimura: "The Multi-Step Effects in the 16 0_ 17 0
Core-Exchange Elastic and Inelastic Scattering", The INS-IPCR Symp. on Cluster Structureof Nuclei and Transfer Reactions Induced by Heavy-Ions, Tokyo, March (1975).
6) K.-I. Kubo and B. Imanishi: "The Recoil Effects in the Core-Exchange Scattering of 16 0_ 18 0",

The INS-IPCR Symp. on Cluster Structure of Nuclei and Transfer Reactions Induced by
Heavy-Ions, Tokyo, March (1975).
7) T. Motobayashi, I. Kohno, S. Nakajima, M. Yoshie, K. Katori, T. Mikumo, and H. Kamitsubo:"Transfer Reactions Induced by 14N on 12C at 79 MeV", The INS-IPCR Symp. on Cluster
Structure of Nuclei and Transfer Reactions Induced by Heavy Ions, Tokyo, March (1975).
8) T. Motobayashi: "Elastic and Inelastic Scattering of 16 0 on 19F", The INS-IPCR Symp. on
Cluster Structure of Nuclei and Transfer Reactions Induced by Heavy Ions, Tokyo, March(1975).
9) T. Suzuki, T. Matsuura, and K.-1. Kubo: "The DWIA Analysis of 2°Ne (0', 20') 16 0 Reactions

at EO' = 78.6 MeV", The INS-IPCR Symp. on Cluster Structure of Nuclei and Transfer
Reactions Induced by Heavy Ions, Tokyo, March (1975).
10) T. Matsuura, K.-1. Kubo, A. Arima, and M. Ichimura: "Do Excited Alpha-Clusters Playa Role in Four-Nucleon Transfer Reaction?", The INS-IPCR Symp. on Cluster Structure of
Nuclei and Transfer Reactions Induced by Heavy Ions, Tokyo, March (1975).
11) H. Kamitsubo: "Optimum Q-valves in the Multinucleon Transfer Reactions and Determinationof the Moment of Inertias", The INS-IPCR Symp. on Cluster Structure of Nuclei andTransfer Reactions Induced by Heavy-Ions, Tokyo, March (1975).
12) S. Nakajima, I. Kohno, M. Yoshie, K. Katori, T. Mikumo, T. Motobayashi, and H. Kamitsubo:"DWBA Analysis of the Single Proton Transfer Reactions Induced by Heavy Ions on the f-p
Nuclei", The INS-IPCR Symp. on Cluster Structure of Nuclei and Transfer Reactions Induced
by Heavy Ions, Tokyo, March (1975).

12313) T. Kammuri and T. Wada: "Folding Model for the Nucleus-Nucleus Interaction", The
INS-IPCR Symp. on Cluster Structure of Nuclei and Transfer Reactions Induced by
Heavy Ions, Tokyo, March (1975).
14) T. Kammuri, H. Yoshida, and S. Yamaji: "Sequential Process in the Two-Nucleon Transfer
between Heavy Ions-Numerical Analysis", The INS-IPCR Symp. on Cluster Structure of
Nuclei and Transfer Reactions Induced by Heavy-Ions, Tokyo, March (1975).
15) S. Ambe and F. Ambe: " 121 Sb-Mossbauer Emission Spectrum of 121mSnS2", 32th Ann.
Meeting of the Chern. Soc. of Japan, Tokyo, April (1975).
16) T. Inamura: "Nuclear Lifetimes of the Recoils", 30th Ann. Meeting of Phys. Soc. of Japan,
Kyoto, April (1975).
17) A. Hashizume, Y. Tendow, T. Katou, and H. Kumagai: "The Cross Sections to Produce
88m Y and 90tn Nb via 89y + a Reaction", 30th Ann. Meeting of Phys. Soc. of Japan, Kyoto,
April (1975).
18) M. Yambe, M. Hirasawa, M. Fujioka, M. Oshima, J. Katakura, S. Hayashibe, and T. Ishimatsu:"The Decay of 119mTe", 30th Ann. Meeting of Phys. Soc. of Japan, Kyoto, April (1975).
19) A. Koyama, E. Vagi, and H. Sakairi: "Secondary Electron Emission from Al and Ni by
Fast-Proton and a-Particle Bombardment", Ann. Meeting of the Japan Soc. of Appl. Phys.
Narashino, April (1975).
20) F. Yatagai, J. Ohi, K. Suzuki, T. Takahashi, and A. Matsuyama: "LET Dependence ofInactivation of Bacterial Cells with Different DNA Repair Capacity", Ann. Meeting of Agr.
Chern. Soc. of Japan, Sapporo, July (1975).
21) S. Motonaga, T. Fujisawa, M. Hemmi, H. Takebe, K. Ikegami, and Y. Yamazaki:"Performance of the IPCR Polarized Ion Source", 4th Int. Symp. on Polarization Phonomena
in Nuclear Reactions, Zurich, Aug. (1975).
22) T. Fujisawa, H. Kamitsubo, T. Wada, M. Koike, Y. Tagishi, and T. Kanai: "Angular Correlation
Measurement for 13C eHe, a) 12 C (4.43 MeV) Reaction", 4th Int. Symp. on Polarization
Phenomena in Nuclear Reactions, Zurich, Aug. (1975).
23) T. Takemasa: "Exact Finite-Range DWBA Calculations for the Reaction 60 Ni

e 0, 160)62Nig.s.",8

Ann. Meeting of Phys. Soc. of Japan Hirosaki, Sept. (1975).
24) T. Ooi, T. Motobayashi, I. Kohno, M. Ishihara, T. Numao, T. Fukuda, and S. M. Lee:
"Role of Critical Angular Momentum in the 12C

e N, 6Li) °Ne Reaction", Ann. Meeting of
4

2

Phys. Soc. of Japan, Hirosaki, Sept. (1975).
25) F. Kakimoto, N. Nakanishi, and H. Ohnuma: " 24 Mg (d, p) 25 Mg at Ed '" 21 MeV," Ann.
Meeting of Phys. Soc. of Japan, Hirosaki, Sept. (1975).
26) H. Sak airi , E. Vagi, A. Koyama, T. Karasawa, and R. R. Hasiguti: "Cyclotron Irradiation
Damage in Copper and Copper Alloys", U.S.-Japan Seminar on Radiation-Produced Defects
and Defects Clusters and Their Effects in Metals, Aimes, Sept. (1975).
27) K. Matsumoto, T. Kataoka, M. Terasawa, M. Shimada, S. Nakahigashi, H. Sakairi, andE. Vagi: "Embrittlement of Austenitic Stainless Steel Irradiated with a-Particles", U .S.-J apan

124

Seminar on Radiation-Produced Defects and Defects Clusters and Their Effects in Metals,
Aimes, Sept. (1975).
28) N. Bendjaballah, J. Delaunay, and T. Nomura: "The Quasi-Band Structure in 57CO", Symp. on
Nuclear Structure, Balatonflirrd , Sept. (1975).
29) T. Nomura, T. Fukuda, K. Hiruta, and W. Kutschera: "Complete Determination of the
Nuclear Alignment of the 8+ State in 216Ra Populated in the 207Pb( 12C, 3n) Reaction",
Symp. on Highly Excited States in Nuclei, Jillich, Sept. (1975).
30) T. Tonuma and M. Odera: "Orbit Analysis of the Riken Heavy Ion Linear Accelerator",
Ann. Meeting of Phys. Soc. of Japan, Hirosaki, Sept. (1975).
31) H. Sakairi, E. Yagi, A. Koyama, T. Karasawa, and R. R. Hasiguti: "Cyclotron Irradiationof CU3 Au Alloys at Low Temperature", Int. Conf. on Fundamental Aspects of Radiation
Damage in Metals, Gatlinberg, Oct. (1975).
32) T. Nozaki: "Charged Particle Activation Analysis. Studies on Carbon, Nitrogen and Oxygen
Mainly in Semiconductor Silicon", Int. Nucl. and Atomic Activ. Anal. Conf., Gatlinburg,
USA, Oct. (1975).
33) F. Ambe and S. Ambe: "Mossbauer Spectroscopic Studies of Recoil 119Sb and 119m Te
Atoms in SnSb and SnTe", 19th Symp. on Radiochem., Fukuoka, Oct. (1975)
34) M. Matsui and M. Imamura: "Heavy-Ion Radiolysis of Liquid Isobutyraldehyde.

Formationof Hydrocarbon by Chain Mechanism", 18th Conf. on Radiation Chern., Tokyo, Oct. (1975).
35) K. Kimura, M. Matsui, and M. Imamura: "Color Center Fonnation in Alkali Halides by
Heavy-Ion Irradiation", 18th Conf. on Radiation Chern., Tokyo, Oct. (1975).
36) F. Yatagai, K. Takeda, K. Shiratori, T. Takahashi, and A. Matsuyama: "LET Effects on
Bacterial Inactivation and Its Repair Capacity", Ann. Meeting of the Japan Radiation
Research Soc., Tokyo, Oct. (1975).
37) S. Kitayama, F. Yatagai, and A. Matsuyama: "Effect of N-Ion Irradiation on DNA
Synthesis in the Penneable Cells of M. Radiodurans", Ann. Meeting of Radiation Research
Soc. of Japan, Tokyo, Oct. (1975).
38) T. Tonuma, F. Yoshida, and M. Odera: "Beam Dynamics of IPCR (RIKEN) Heavy Ion
Linac", Int. Conf. on Heavy Ion Sources, Gatlingburg, Tennessee, Oct. (1975).

125

14. LIST OF PERSONNEL

Members of the Board
HAGIHARA Hitosi ~- mi
1= (Chairman)
KAMITSUBO Hiromichi .L ~ 7R Jjj
NOZAKI Tadashi!f UffitlE
Users Committee=

HAMADA Tatsuji ~ B3 ii(Chairman)
KAMITSUBO Hiromichi .L :lf 7R ill
MA TSUY AMA Akira
fl W :Y6
1]\ -:;:t- lE {~ODERA Masatoshi~iR
MJ
SEKIZAWA Hisashi

HAMADA Tatsuji
NAKANE Ryohei
ODERA Masatoshi&B3ii-=Jf:l fN R ilL

IJ\ -:;:t- lE {~IMAMURA Masashi~ R
KOHNO Isao
M !fJ}]
NOZAKI Tadashi!f UffitlE
SAKAIRI Hideo
t& A !If ~El
E3

Operation and Machine Maintenance Group
FUJITA Shinhi B3~
KAGEY AMA Tadashi ~ w it:
KOHNO Isao
M !f
J}]
OGIWARA Kiyoshi
W( 1*
~.

IKEGAMI Kumio
KOHARA Shigeo
NAKAJIMA Hisao
T AKEBE Hideki

tth.L 1L ~'-lx

IJ\ Jffi m:
Jf:l ~~ MJ ~rEt$~mScientific and Engineering Personnel
Cyclotron Laboratory
FUJISAWA Takashi
hi iR ~ ~INAMURA Takashi
frB R
!j[
KAMITSUBO Hiromichi.L :If 7R ill
KOHNO Isao
~1iJ ~f~
MOTONAGA Shoshichi
x 7k fiB t
NAKANISHI Noriyoshi
Jf:l ~ ff-C ~SUZUKI Toshio~
fitJ. 5i5
Y AMAJI Shuhei
Lli ~ {~ ijL ***=FU JIT A J iro
Jii B3~r~
ISHIHARA Masayasu
D" @ lE ~KARASAWA TakashimiR 4MATSUURA Toshihiko
fl 1ffi {~ It
NAKAJIMA Shunji
Jf:l fIb ~~NOMURA Toru
!f R
:If *
WADA Takeshi:f11 B3
lit=(Visitors)

m

*
'*

R
fit
(Univ. of Tokyo)
ICHIMURA Munetake
FUJINO Takeo
Iii !f 1lt x(Univ. of Tokyo)
HANAZONO Sakae rt til(Univ. of Tokyo)
HIRUTA Kotaro~ B3 ¥ *~r)
(Tokyo Inst. Tech.)
IMANISHI Bunryu 4' P..§ )( ~(Nihon Univ.)
KAMMURI Tetsuo m ~(Univ. of Osaka)
KATORI Kenji
11! 1& ~(Tokyo Univ. of Educ.)
KAWAI Mitsuji
M -il :7't ~(Tokyo Inst. Tech.)
KOIKE Masahiro
IJ\ tth lE 7R(Univ. of Tokyo)
MIKUMO Takashi~ ~ED (Tokyo Univ. of Educ.)
OHNUMA Hajime*-. 113
ffi (Univ. of Tokyo)
SAKAGUCHI Harutaka
1;& D 7t ~ (Kyoto Univ.)=x* On leave of ab sence to : DPHNBE, CEN Saclay , B.P. 2, 91190 Gif/Yvette , France** On leave of absence to : Institut fUr Theoretische Physik der Universitat Frankfurt/M 6 Frankfurt/M.I, Robert-Mayer-Strasse
8-10, West Germany .

126

TAKEMASA Tadashi lit i& jI- ±(Univ. of Osaka)
WAKAI Masamichi ~ # 1£ ill(Univ. of Osaka)"51 (Tokyo Inst. Tech.)
YOSHIDA Hiroshi -a B3
YOSHIE Morio"5 IT ~ ~(Tokyo Univ. of Educ.)
Linac Laboratory (Electronics Laboratory)
CHIBA Y oshiaki=f ~ Iff fljj
INOUE Toshihiko # 1:. ~ ~ODERA Masatoshi
IJ\ -;f 1£ 13t
TONUMA Tadao
P 113 1£ ME

HEMMI Masatake~ J! i& IE\,
MIY AZAW A Yoshitoshi'§ iR f:t ~SHIMAMURA Akira~ ,ft~
YOSHIDA Fusako s B3 m -f-(Students)
FUKUDA Tomokazu
t~ B3 +t ;fO(Univ. of Tokyo)
MOTOBA YASHI Tohru ;;$:;f,t:® (Univ. of Tokyo)
NUMAO Toshio
m~ ~ ii5 ~(Univ. of Tokyo)
001 Takao*- # -:Jt. m (Tokyo Univ. of Educ.)
TANAKA Koichiro
B3 ct-J;ffr-~15(Univ. of Tokyo)
Radiation Laboratory
AWAY A Y ohko
~ J¥. :g -fHASHIZUME Akira
m JT\ Wi
KATOU Takeono iii IE\, ME
KUMAGAI Hidekazu!f~ ~ 1§ ;fO
TAKAHASHI Tan~ m l:i=

HAMADA Tatsuji~ iE ~IZUMO Koichi
tfj ~ :Jlt - KONNO Satoshi~ !f~f,Lj !f ~ m
OKANO Masaharu
J(.i]l7im
TENDOW Yoshihiko(Visitors)i]l ~ ,,&, ~(Waseda Univ.)
DOKE Tadayoshi
FUJIOKA Manabu
iii 1m~ (Tohoku Univ.)
f,f $ IlB -j§(Tohoku U niv.)
HAY ASHIBE Shogo
110 Masahiro ~ ~ 1£ 7.i.
(Tokyo Metropol. Jeriatric Hosp.)
NAGAHARA Teruaki 71< 1* ,8,~ Ujj(Rikkyo Univ.)~~(J apan Anal. Chern. Res. Inst.)
SUZUKI Kazuaki*-

Nuclear Analytical Chemistry Laboratory
AMBE Fumitoshi
ARA T ANI MichiIW AMOTO Masako
SAITO N obufusa

~$x~
m~~~

:fi;$:1£-f~ iii f§' m

AMBE Shizuko~ $ Mt -fITO Y oshiko
W 7i -=rNOZAKI Tadashi
!f ~
1£

*

(Visitors)t~ ±m (Nat. Inst. of Radiological Sciences)
FUKUSHI Kiyoshi
HARA Toshihiko1*~ ~ (Nat. Nakano Chest Hosp.)
IDO Tatsuo# P ~ ME
(Nat. Inst. of Radiological Sciences)
KASIDA Yoshihikom B3 R ~ (Nat. Inst. of Radiological Sciences)
TAKI Koh it~ (Kitazato Univ.)
YATSURUGI Yoshifumi
J\ ~IJ s X(Komatsu Electronic Metals Co. , Ltd.)

127

Synthetic Organic Chemistry Laboratory
OSAWA TomihikoRadiobiology Laboratory
KIT A Y AMA Shigeru:.it III~YATAGAI Fumio~ ill ~)(:X

MATSUY AMA Akira

Radiation Chemistry Laboratory
IMAMURA Masashi
MATSUI Masao

KIMURA Kazuie

El

E3

Metal Physics Laboratory
KOY AMA Akio
IJ\ U-I Bfl Mt
SHIOTANI Nobuhiro
j;g :& ][ ~l

* Mt
**-

Jjj A
SAKAIRI Hideo
YAGI Eiichi)\

Magnetic Materials Laboratory
OKADA Takuya

SEKIZAWA Hisashi(Visitor)
MIZOGUCHI Tadashi

il 0

if (Gakushuin Univ.)

Work Shop
TAKESHITA Isao

YOKOYAMA Ichiro

Radiation Monitoring and Safety Office
IGARASHI Kazui
SAKAMOTO Ichiro

KODA Kugao
USUBA Isao

Ej3 ill I~ ~

Ii ~

~

128

15. LIST OF OUTSIDE USERS AND THEIR THEMES(Jan. - Dec. 1975)

1)

M. Nakamura,

Kyushu Univ.

"Production of 43 Kr for Heart Scanning"2)

Y. Homma,

Tokyo Metropolitan Univ.
"Production of 61 Cu, 123 1 and 123 1"

3)

K. Shiraishi, A. Hishinuma, and K. Kazuho,

Japan Atomic Energy Research Inst.

"Radiation Damage of Stainless Steel by Alpha Particles"
4)

Japan Atomic Energy Research Inst.

T. Katou, S. Kawasaki, and T. Furuta,"Study of Effect of Helium Bubbles on the Mechanical Behavior of Stainless Steel"5)

M. Terasawa, M. Shimada, and M. limura,Toshiba R. & D. Center"Cyclotron Irradiation for Study of FBR Material Embrittlment"
6)

A. Furusawa and S. Tamaki,

Niigata Univ.

"Production of 1241 for Perturbed Angular Correlation Measurement"
7)

S. Shikata,

Kyushu Univ.

"Production of 53Mn"
8)

Inst. for Nuclear Study, Tokyo Univ.,

K. Komura, M. Sakamoto,* and A. Ando,***Kanazawa Univ., and **Junior College of Medical Technology"Production of 167Tm for Medical Use"9)

I. Kuze,

Japan Radioisotope Association"Production of 56CO."
10)

H. Nakahara and M. Yanokura,Tokyo Metropolitan Univ.

"Measurement of the Excitation Function for 121 Sb eHe, a) 122 Sb and 123Sb(a, 3He)122 Sb
Reactions"II)T. Furusawa, M. Hishinuma, and K. Fukai,

Japan Atomic Research Inst.

"Study of Stainless Steel Swelling by Helium Injection"
12)

Y. Murakami and Y. Homma,"Production of 61CO"Tokyo Metropolitan Univ.

13)

Y. Murakami, E. Shirai, and M. Unno,

Tokyo Metropolitan Univ.

"Production of 61CU, 67Ga, and 68Ge"
14)

M. Honda, O. Nitou, and R. Genshou,Inst. for Solid State Physics, Tokyo Univ.

"Production of Mg Isotopes"
15)

K. Shiraishi, A. Hishinuma, and K. Fukai,

Japan Atomic Research Inst.

"Helium Effect on the Formation of Void in SUS316 by Electron Bombardment"
16)

H. Nakahara,

Tokyo Metropolitan Univ.

"Study of Direct Process in the Nuclear Reaction"

129

AUTHOR INDEXAKIBA Mitsunori;fJe ~ ]t 1ff!.t

AMBE Fumitoshi

tJl. $ X fifi

AMBE Shizuko
AWAYA Yohko

76, 79

A. U ~ :!it

IRIE Toshiaki

101

87,89

ISHIHARA Masayasu

1] @: iE ~tJl. $ f¥ T

89 , 101

ISHIMATSU Toshiyuki

1] fl fifi

~ ~?G T

76,79

IWAMOTO Masako

Ii ~FUJIOKA Manabu$

Iii ~ ~ ,~FUJISAWA Takashi
FUJITA JiroIi ill= ~~FUJITA Shin

Iii B3~

4,38,46,51

FUKUSHI Kiyoshifi ±HAMADA Tatsuji~ B3 i!

59, 62

101

101
~ W

KAGEYAMA Tadashi

z

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2,6

67

KAKIMOTO Fumio:I:§'* ~ m 41

2,6,108

KAMITSUBO Hiromichi

1: PJZ 7.l. ii

fi B3 ~ ;fD

FUKUDA Tomokazu~:6 illIWATA Len

59,62'* iE T

:6

10, 13, 15 , 71

10,13, 15

17 , 19, 46, 51 , 71

KAMMURI Tetsuo* Ji I3jj

m 101

KANAI Tatuaki=

79,103KARASAWA Takashim~~46, 51

4-

101

HARA Masahiro@:

Jt 51,.

38

KASIDA Y oshihikomill ~ Jft

101

HARA Toshihiko@:fifi Jft

101

KATAKURA Junichi

h ~ *4i. -59,62

HASHIMOTO Yoshio

m'* $l( :;R.

HASHIZUME Akira

mJ!\

AA

38

KATORI Kenji

54,56,62,70

KATOU Takeo

HASIGUTI R. Ryukiti

m 0 ~ 5"

HAY ASHIBE Shogot* $ at! ~ 59, 62

HEMMI Masatake~ ~ il& fB:

IDO Tatsuo:#- pi il m

59,62

KIT A Y AMA Shigeru

KOHARA Shigeo

IKEGAMI Kumio

ilQ 1: 1L ~ ~IMAMURA Masashi

4- t-tIMANISHI Bunryu

4- ~ X 1m

INAMURA Takashi

frB t-t

INOUE Toshihiko:#- 1: fifi Jft2, 6, 8~~93

j~ ill~;'OJ ~

Jj]

98

105, 107

Ij\ @: :i::;R.

6, 82, 10, 19, 22 , 38, 65

KOIKE Masahiro

46, 51

IJ\ w at! m

91,93

KOYAMA Akio

29, 32, 35

KUBO Kenichi

13, 15, 71, 72

KUMAGAI Hidekazu

113

54,56,76,79

¥

;ft -

Ef3 ill '~i ~KOHNO Isao

101*

KIMURA Kazuie

KODA Kugao

4, 111ilL ~ iE 1"§

HIRASAWA Masanobu

82

110 Iii fB: m

LEE. S. M.

1082~~ ~ ~ ;fD

54,56,70, 79

130MA TSUI Masao

flit if ~SAKAMOTO Ichiro

tJj :;$: -~~103,105,107,1 08

49,51

SEKIZAWA Hisashi

MiR

!oJ

85,87

95,98

SHIOTANI Nobuhiro

91

fl 00 {~ jft

MATSUURA Toshihiko

fl w

MATSUY AMA Akira~-giR{*~MIY AZAWAY oshitoshi
MOTOBA Y ASHI Tohru

~

*'*

:;$:

113
4, 10, 19,22,
29,38,65

5ClkBt3t

MOTONAGA Shoshichi

75

NAGURA Riichi

SUZUKI Kazutoshi~ ~~ iI!iJ Mt

NAKAJIMA Shunji

~ ~

§'*

2, 6, 8=~*;fO£j:.

TAGISHI Yoshihiro

mz fl ~ A

NARIMATSU Yoshito

133j$~*

41,44, 73
73

T AKEMASA Tadashi

TIt i& jr ±TAKESHITA Isao

r.r T ~ ~TAKI Ko$

T ANIMURA Osam u

~ tt

~ ,ft

J:jr

15,71

TAW ARA Hiroyuki~

101

TENDOW Y o shihik 0

J2. ill 1J jft

10,13,15

TONUMA Tadao

110,111,113,
115,117,118

USUBA Isao

NUMAO Toshio

1B~IL0~ifmm

IJ\ ~ if ~OGIWARA Kiyoshi

~'*

m 2,6

WADA Takeshi

fD EE

OHNUMA Hajime

*- 1B

ffi

YAGI Eiichi;\ * '* -OHSAWA Tomihiko*-~J{iIt

OKADA Takuya~ EE !j[ -jQ

OKANO Masaharu

f!Lj !f*- jffi*- it 4- Mt

SAKAIRI Hideo

101

YAMBE Masaru

59, 62YAMAJI Shuhei*-iR@;jft85,87

J{ rt:l101,103

f~

35

~ Z

76

pi 1B if Mt

ODERA Masatoshi

41

lQ

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YATAGAI Fumio

54,56, 76, 79

115,117

105,107tt

46,51,71

82

if

59,62

~EEJ§.)(~

95,98

YOKOYAMA Ichiro

35

YOSHIDA Fusakoi§" EE

mr

10, 19,65

YOSHIDA Hiroshii§" EE

jL

~l.

29

101

103

!f UffiJ

SAGARA Kenshi

38

4, 118EE ;fiE ~NOZAKI Tadashi

001 Takao

46,51

~m%$

TAKAHASHI N oriyuki~

NISHIDA Masami

ONISHI Hiroshi

101

T AKEBE Hideki

22,65~ ~ ~.@:NAKANISHI Noriyoshi

OHSHIMA Masumi

85

TAKAHASHI Tan

NAKAJIMA Hisao

NOMURA Toru

iM~lI~L

YOSHIE Morioi§" U ~ ~115,11724

19,22

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理化学研究所
埼玉県

和光市

広沢