the Institute of Physical and Chemical Research
Yamato-machi, Saitama Pref., JAPANIPCR cyclotron
Progress Report 1967

Vol. 1

Edited by Administra tion Committee of the IPCR Cyclotron

IPCR Cyclotron Progress Report 1967
Vol. 1The Institute of Physical and Chemical Research"RIKAGAKU KENKYUSHO" Yamato-machi, Saitama Pref., JAPANNovember, 1967

Dedicated to the Memory of
Dr. Yoshio NISIDNA(1890 -----1951)

The cyclotron. The yoke of magnet is seen on the right and the oscillator
on the left. On the foreside of the photo the beam switching magnet and fivecourses of beam pipe are seen.

All rights reserved . This report or any part thereof may not be reproduc edin any form (includin g photosta tic or microfil m form) without written permi~sionfrom the publis her.

CONTENTS

Page
1.

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

1

2.

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

2

3.

MACHINE DEVELOPMENT . .. . .. . . .. . . . .. .. . . . .. . . . .. .. .. .. .. . . ... . .. . .. . . . . .. .. . . . . . ..

4.. . .. . .... . ... ... .... .. ... .. ... .. .. . ... ... ... ...

4

4.

5.

6.

3 -1.

Outline of the IPCR Cyclotron

3-2.

Beam focusing System.... ... ...................................................

10

3-3.

Circulation System of 3He Gas ........................ ·. ... .. .. .. . .. . . .... .. . . .

13

3-4.

On the Multi charged Heavy Ion Source . . . . . .. . . .. . .. . . . . . . . . . . . . .. . . . ......

16

3-5.

Design of the focusing Magnetic Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

19
25

ACCELERATOR PHYSICS
4-1.

Initial Motion of Ions ...... ............. .... ....... ... ..... ...... .. .. .... ...... ..

25

4-2.

Investigation on Electromagnets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .
Hysteresis Effect of Field Distribution

29

33

NUCLEAR PHYSICS
Scattering and Reaction

5-2.

Elastic and Inelastic Scattering of 3He from Ni Isotopes . . . . . . . . . . . . .

37

5-3.

Elastic Scattering of 3He from Ca. .... .......... .................. ....... ..

41

5-4.

Coulomb Excitation with Alpha-particles .......... .......... ...... ... . ....

44

NUCLEAR PHYSICS
Nuclear Spectroscopy and its Applications

50

6-1.

Measurements of Internal Conversion Electrons

50

6-2.

Nuclide Analysis using Nuclear Reactions . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . .

53

7.

8.

9.

NUCLEAR INSTRUM ENTATION S AND TECHNIQ UES ............. .............

54

7-1.

The 7 5 em Scattering Chamber . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . .

54

7-2.

An Air-core Beta-ray Spectrom eter ............. ............. ............. .

58

7-~.

A Broad Range Magnetic Analyzer............. ............. ............. ...

60

7-4.

Data Processin g System

62

7-5.

A Charge Spectrom eter

65

RADIOCH EMISTRY . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

66

8-1.

Charged -particle Activation Analysis .. .. . . . .. .. .. .. . . .. . .. . . . .. .. .. .. . . .. .

66

8-2.

Recoil Chemistry ............. ............. ............. ............. ............

67

RADIATION C~EMISTRY AND RADIATION BIOLOGY ............. ............

70

LET Effects in the Radiation Chemistry and Radiation Biology .....

70

SOLID STATE PHYSICS ............. ............. ............. ............. ............. .

72

Radiation Damage in Solids .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. . . .. . . .. .. . .. . .. . .. ..

72

RI PRODUCTION AND ITS APPLICATIONS . . .. .. .. . .. . .. .. . . .. .. .. . .. . . .. . .. . .. .. .

73

9-1.
10.

10-1.
11.

12.

The Irradiatio n Sys tern

11-2.

Safe Handling of irradiated Targets. .. .. .. . .. . .. .. .. .. .. . .. . .. .. .. . .. .. .. ..

75

11-3.

Preparatio n and Isolation of Carrier-f ree 76As from 78se ...........

76

11-4.

Preparatio n of 18F-label led Compound s ............. ............. .........

77

RADIATION MONITORING ............. ............. ............. ............. ..........

81

12-1. · Radiation Monitorin g Station .... ............. .............. ...... .............

81

Health Physics

83

LIST OF PERSONN EL

87

12-2.
13.

73

11- 1.

ii

Illustrations
Page
Fig. 1 (3-1)

Scheduled range of particle energy of the IPCR cyclotron .......

6

Fig. 2 (3-1)

Final field distributions obtained by the measurementwith model magnets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7Fig. 3 (3-1)

Magnet and acceleration chamber .. . . . .. . .. . . .. .. . . .. .. .. .. .. .. .. .. .. .

8

Fig. 4 (3-1)

Oscillator and stem tank .. . ... . .. . . .. . . . ... . .. .. . ... . . . ... . . . . . . ..... .. . .

9Fig. 1 (3-2)

Layout of the beam transport .................._.........................

12

Fig. 1 (3-3)

The diagram of the circulation system ...............................

14

Fig. 2 (3-3)

The diagram of gas flow.... .... .. .. . .. .... . . ... ... .. ... . ... ... .... . ... . .

15

Fig. 1 (3-4)

Ion source and block diagram for power supply . .. .. .. .. . .. . . . . . ..

16

Fig. 2 (3-4)

Ion source for bench test

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

17Fig. 3 (3-4)

Spectrum of nitrogen ion beam from nitrogen gas discharge ...

18

Fig. 4 (3-4)

Spectrum of oxygen and carbon ion beam from C0 2
discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18

Measured beam spread and the expected focusing effect of
the channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21

Field induced by an infinitely long bar ( 1-t = oo ) placed in
the uniform magnetic field ..... .... ....... ..... ...... ..... ..............

22(a) Schematic diagram of the focusing channel23(b) Field distribution in the median plane of 1/31scale
magnetic channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

23

The design of channel indicating the position adjustingmechanism ................................................................. ..

24

The central cyclotron region, showing the ion source,
feeler, and dees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

26(a) The case of west dee injection.
(b) The distancefrom the ion source to the first turn vs. the normalized
dee voltage .... ........ ....... ..... .... ........ ........... ..... ..... .........

27

Fig. 1 (3-5)

Fig. 2 (3-5)

Fig. 3 (3-5)

Fig. 4 (3-5)

Fig. 1 (4-1)

Fig. 2 (4-1)

iii

(a) In the case of west dee
Beam density vs. radius.
(b) In the case of east dee injection . . . . . . . . . . . . . . . . . .
injection.

2.8

General view of the switching and analyzing magnets for
the IPCR cyclotron beam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

30

Variation of the field distribution along the beam path inair gap depending on the cases of increasing and decreasing
the field strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

31

Improvement on the field distribution by attaching the ironpieces to an edge of the pole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

32

Pulse height spectra of 3He and a -particles obtained atfJ lab. = 30° from the bombardment of 27 Al with 24.2 MeV
3He particles . . . . .. . . . .. .. . . .. . . ... . ...... .... ... . . . . . .. . .. ...... .. . .. . . . ... .

34

Angular distribution, expressed as a 1 a R, for the elastic
scattering of 24.2 and 31.5 MeV 3 He particles .....................

35

26
Angular distribution of a -particles for the 27 Al (3He, a ) Al
reaction leaving 2.6Al in the ground and third excited states . . .

36

Fig. 1 (5-2)

Angular distribution of the elastic scattering . . . . . .. . . . . . . . . .. . . . . .

38

Fig. 2 (5-2)

Pulse height spectrum. . ... ..... ... ..... .... . ... . .. .. .. .. .. .. . .... . ... .. ..

39

Fig. 3 (5-2)

Angular distribution of the inelastic scattering . . . . . . . . . . . . . . . . . . . .

40

Fig. 1 (5-3)

Angular distribution of the elastic scattering .. . ... . ... . .. . . . .. . .. .

42

Fig. 2 (5-3)

A preliminary fit of the angular distribution . . .... ..... ... . .... .. . .

43

Fig. 1 (5-4)

Gamma-ray spectrum of 181Ta ................................ ........

46

Fig. 2 (5-4)

Gamma-ray spectrum of Ag ................................ ............

47

Fig. 3 (5-4)

Gamma-ray spectrum of 197Au ................................ ........

48

Fig. 4 (5-4)

Energy levels in 197 Au

49

Fig. 1 (6-1)

Momentum spectrum of the conversion electrons from

Fig. 3 (4-1)

Fig. 1 (4-2)

Fig. 2 (4-2)

Fig. 3 (4-2)

Fig. 1 (5-1)

Fig. 2 (5-1)

Fig. 3 (5-1)

198Au ································ ································ ··········

52

Fig. 1 (7 -1)

Sectional view of chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

55

Fig. 2 (7-1)

Side view of chamber.. .. ... ... . .... ..... . ... ... .. . ... .. . . ... . ... . ... . .. ..

56

iV

Fig. 3 (7 -1)

Top view of chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

57

Fig. 1 (7 -3)Upper drawing shows a designed magnetic field configurationin the median plane of magnets and typical particle
trajectories. In the lower side calculated values aretabulated .. .. . .. . . . . . . .. . . .. . . .. . .. . . . . . . . . . . . .. . ... .. . .. .. . . . . . . . . . . . . .. . .. . ..

61

Fig. 1 (7 -4)

DDP-124 PHA system configuration ...................................

64

Fig. 1 (9-1)

Relation between optical density (F e3+) and total charge
input .. .... ....... ... ..... .... ........ ... ....... ...... ... . ....... ......... ......

71

Fig. 1 ( 11- 1)

Irradiation system for RI production

74

Fig. 1 (11-4)

Thick-target saturation activities for the 16o +a 18F
and the 16o + 3He 18p reactions in 02 .. .. . .. .. . . . . .. . . . .. . . .

78

Equipment for preparing anhydrous HF18 by charged· particle bombardment of an oxygen stream . . . . . . . . . .. .. . .. . .. .. .. .

79

Fig. 3 (11-4)

Elution curve of H 18 F from a silver bombardment vessel

80Fig. 1 (12-1)

Record of radiation monitoring at the station 85 m apartfrom the cyclotron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

82

Fig. 1 (12-2)

Machine leakage radiation (neutron and gamma)

85

Fig. 2 ( 12- 2)

Residual activity pattern (I)86Fig. 3 (12- 2)

Residual activity pattern (II)86

Fig. 2 (11-4)v

1

1. INTRODUCTION

Before the World War II, two cyclotrons of 26" and 60" were constructed in IPCR,
the abbreviated name of the Institute of Physical and Chemical Research, "RIKAGAKU
KE NKYUSHO" in Japanese.
In those days the 60" cyclotron was the largest in the Far East. The old IPCR
cyclotron of 26" was first successfully operated in 1937 under the supervision of thelate Dr. Yoshio Nishina, and since then an extensive program of experimental researches by use of this device had been launched. Just after the War, both machines
were destroyed and thrown into the Tokyo Bay by the occupation army.
In 1952 a small cyclotron of 26" was reconstructed and we began our researchworks on a small scale. A larger cyclotron of 63" was constructed on a new site when
our institute was moved to Yamato-machi, ~aitama Prefecture, Japan, about 13 km distant from the old site, Honkomagome, Tokyo. We started operation of the new machinefrom the fall of 1966.
The new machine is an ordinary type cyclotron capable of accelerating various
particles to a wide range of energy and particularly useful for accelerating heavy ions.
The subjects of research using this cyclotron are not only related to nuclear physics,
but also cover a wide field of science, namely, radiochemistry, radiation chemistry,
radiation biology, solid- state physics and radioisotope production.
The first volume of IPCR Cyclotron Progress Report reviews the present status of
the new cyclot·ron in general and contains the summaries of research, technical development and other activities involving the cyclotron, which were carried out fromJanuary to June, 1967. The cyclotron was operated as a research tool for the membersof our institute during this period. The operation of the machine is undertaken by the
Administration Committee of the IPCR cyclotron.
The construction of the machine was supervised by the Cyclotron Construction
Committee of this institute (Chairman: Dr. Hiroo Kumagai). The financial support forthe construction of machine and the research works were mainly given by the Government. Here, we should like to express our thanks to those who backed up the projectof the IPCR cyclotron.
Acknowledgment must also be made to the members of the Japan Atomic Energy
Committee, and Mr. ·Haruo Nagaoka, former President of the Institute, without whose
continued support and interest the IPCR cyclotron could not have been realized.

Fumio Yamasaki, Chairman
Administration Committee of
the IPCR Cyclotron

2

2. MACHIN E OPERATION

The first beam was obtained from the IPCR cyclotron on Oct. 4, 1966. The beamof N4+ was accelerate d to 56 MeV and deflected on Jan. 12, 1967, whose inte~sity at theexit radius was about 5 p, A. Since Feb. 6, 1967, the cyc~otron has been used for research works. There occurred no serious fault but some minor failures were foundand repaired. These are:Vacuum discharge which was mainly caused by the soft solder on the part of(1)
liner.
RF voltage breakdown at the shorting bar.
(2)
Mechanica l failure at the moving parts of the liner and the shorting bar.
(3)
(See 3 -2.)
Gas discharge at some undesirab le portions in the ion source and in its( 4)
feeder.
The beam energy and the beam intensity have not yet reached the target values.
The maximum conditions now attained are:- the alpha -particle energy is 40 MeV and3
the deflected current of He is about 30 /.I..A. There are several points which must be
improved; one is the vacuum spark of RF voltage which limits the dee -ground peakvoltage under 100 kV, while its target value being 130 kV, and the other is the mismatching between the deflected beam and the beam transport system. Beams travel
through a long path (about 1150) in the fringing field of the B-constan t magnet andneither magnetic nor electric channel device is applied. This design was adopted tofacilitate the beam extraction under a wide range of the magnetic field strength (0.5 -2 Wbjm2). It caused, however, a remarkab le spread of horizontal beam divergenc e,
and only about 20% of deflected beam was caught by the beam transport system. To
solve this problem, a magnetic channel which might be used over the wide range offield strength was designed (See 3-5 ). The source of heavy ion (See 3-4 ) was operated successfu lly. This has, however, not yet been used for research works, because the stability is not so reliable as to operate continuou sly under the cyclotron
condition. For about a half of the running time, 3He ions are accelerate d and theirenergy covers from 12 MeV to 40 MeV. The performan ce of gas circulatio n system
is good and the intensity of analyzed 3He beams is enough for the nuclear scatteringexperimen t (See 3-2, 5-1, 5-2, and 5-3).
The machine is operated on a 2 shifts 24 hours per day system. Every two weeks
or every month, the operating schedule is planned. Scheduled running days and available days for each research subject, and days used for maintenan ce are given in Table
1 (2). Of these subjects, only the alpha -particle beam of 11 MeV for the Coulomb
excitation study was difficult to obtain. For the other subjects, however, no serious
problem on beam intensity nor on beam quality remained at the last stage of thisperiod. Since the available machine time, which includes the time needed for the
beam handling, was about 80% as shown in Table 1 (2), a more efficient use of researchgroup is desirable.

3

Table 1 (2).

Machine time from Feb. 6 to July 12 (Total 157 days)

Subjects

Days s.c heduled

Days available

5-1

27 Al(3He, a)

23

21

5-2

58,60Ni( 3He, 3He')

21

19

5-3

Ca + 3He

18.5

16

5-4

Coulomb excitatio n

10

5

6-1

Nuclear spectros copy

4.5

3

7 and 11 Radioch emistry
and ·radio isotope
producti on

8

7

9-1

LET effects

6

6

10-1

Radiatio n damage

1

1

6-2

Analysis of nuclide

1.5

1.5

4-1

Initial motion

12

12

3

Machine developm ent

14

14

Maintena nce

1313

And others

9.5

Total

142

118.5 (83.5%)

4

3. MACHINE DEVELOPMENT

3-1. Out I ine of the IPCR Cyclotron.

The cyclotron!) was installed at the Institute of Physical and Chemical Research,(RIKAGAKU KENKYUSHO, Yamato-mac hi, Saitama Prefe€ture, Japan). The design isan ext~nsion of the variable energy ordinary cyclotron at the Institute for Nuclear
Study (INS), the University of Tokyo.2) The main difference lies in the new programto accelerate heavy ions. The kinds of particles and the ranges of energy expected tobe obtained with this machine are illustrated in Fig. 1 (3 -1).
The cyclotron, of course, accelerates protons, deuterons, (tritons), 3He ions andalpha-partic les of different energies. Multiply-cha rged ions of carbon, nitrogen andoxygen will be accelerated over a wide energy range as shown in Fig. 1 (3-1), if asuitable ion source is developed and a sufficient RF voltage is obtained.
To carry out such a variety of operations, the cyclotron was designed to haveseveral notable features as follows*.
Firstly, the magnet is required to produce magnetic induction ranging
Magnetfrom 0.5 Wb/m2 to 2.0 Wb/m2. 3) Experimenta l studies performed with model magnets gave a solution to make the variation of the field distribution with excitation isso small as shown in Fig. 2 (3-1). The profile of pole piece3),4) is of such a shape as
to keep the magnetic induction nearly uniform inside the pole piece iron and the Roseshim was omitted. Four sets of circular current shims installed on the pole faces areused for the field shaping.
The frequency of the oscillator is required to cover theRadio frequency system
range from 6 MC to 13.5 Mc.S) For this purpose, the shorting bar on the Lecher typestem and the liners facing the dees were designed to be movable. They co-operate toachieve the variation of resonance frequency. The coupling loop between the resonating tank and the oscillator tube must also be moved and the couping condenser must bechanged in a wide change of frequency.
For operation at a higher frequency than 12 MC, some large scale changes of thesystem are inevitable, such as the removal of moving liners and the exchange of plate
loop. This kind of drastic change has not yet been tried. To enlarge the range ofenergy, a large value of RF voltage will be required and the target value of the deeearth voltage may be 130 kV. However, under the present status it has been limited
by vacuum spark to the value less than 90 kV.
An outline of the cyclotron is given in Figs. 3 and 4 (3-1) and in Table 1 (3-1).

5

Table 1 (3-1): Design specifications of the IPCR cyclotron

Type of magnet :Pole tip diameter :Gap between pole tips :Exit radius :Gaps between dee and movable liners :Maximum magnetic induction :Frequency range of oscillator :Maximum dee -earth voltage :Expected particles and their energy:p3-- 16 MeV or higherd
6- 20 MeV (25 MeV)a
12 -40 MeV (48 MeV)
N4+ 56- (100 MeV)

No sector, ordinary type
160 em
26 em
74 em
3.0-5.5 em
2.0 Wb/m2
5.2 to 12 (13.3) MC
80 (120) kV*The main part of the machine was manufactured by Nippon Atomic Industrial GroupCo. Ltd. (NAIG) in co -operation with Tokyo Shibaura Electric Co. Ltd. (TOSHIBA).

References
1)
2)
3)
4)
5)

Cyclotron Design Group: Reports I.P.C.R. (in Japanese), 41, 113 (1965)
S. Kikuchi, et al.: J. Phys. Soc. Japan, _!2, 41 (1960)
S. Motonaga, et al.: Reports I.P.C.R. (in Japanese), 40, 1 (1964).
H. Kumagai: . Nucl. lnst. and Meth., 6, 213 (1960).
Y. Chiba, M. Odera and T. Fujisawa: Reports I.P.C.R. (in Japanese), 40,
67 (1964).

63Particle Energy (MeV/ nucleon)
5
10
15
20

20
18

\~
,~

16
,_...__
C/)
(/)

\L/
,~
,~

14

c9~

='

d
(!J
I

~

\ ~·
\ ,~
~·

12

"'--"'

-o

-

Q)

LL
(.)

·+->

0 l d rr R1KEN ''60" Cyc 1otron

10

9

<D
~

0')

d

2

8

7

6

6

Fig. 1 (3-1)

12
8
7
9 10
Radio Frequency ( MC)
Scheduled range of particle energy of
the IPCR cyclotron.

15

7

97

96

fig. 2 (3-1)

Final field distributions obtained by themeasurement with model magnets.

8a) plan viewllb)side v1ew(1) Radio frequency shorting condenser, (2) Deflector, (3) Vacuum pump,(4) Beam probe, (5) Ion source positioning machanism,(6) Gate valve for activation probe, (7) Coil, (8) Dee,
(9) Capacity compensator, (10) Movable liners driving shaft,(11) stem tank, (12) Hole for vertical ion source,(13) Upper yoke of magnet, (14) Oscillator house,(15) Dee stem, (16) Ion source supporting bed,(17) Rail for the ion source motion, (18) Movable liner.
Fig. 3 (3-1)

Magnet and acceleration chamber.

9a) side v1ew

M

GOGG
0000

K

D

L

b) plan v1ew

A: Oscillator tube, B: Plate loop, C: Cathode loop, D: Dee, E.: Dee
stem, F: Shorting plate, G: Stem supporting gimbal, H: Dee positioning
mechanism and cooling pipe connectors, I: Stem tank carriage, J: Large
flange for the connection of tank to acceleration chamber, K: Oscillator
house, L: Rack for water flow relays and valves, M: Meter panel,
N: Stem tank shell
Fig. 4 (3-1)

Oscillator and stem tank.

103-2. Beam focusing System

S. Motonaga, H. Kamitsubo, M. Hemmi,
N. Nakanishi, and K. Matsuda(1) Introduction
The beam focusing system for the IPCR cyclotron is described briefly. Muchattention was paid to a beam analyzing system in the design to obtain high resolution
beam together with flexibility for further development.
Some modifications and changes will be made in the near future when enough experience about the beam behavior is gained.
Now, these systems are working with cyclotron beam but have not yet fulfiled all
kind of requirements for the cyclotron beam as described in § 2.
(2) General Layout and Operation
Fig. 1 (3 -2) shows a general layout of the focusing system now under installation.
The beam is deflected by an A.C. deflector, focused with a pair of the quadrupole magnets Q -0 and directed into a switching magnet SW, which bends it into one of the fiveexperimental courses. These courses have been used for various experiments ofnuclear physics, solid state physics, nuclear activation and radiation chemistry. We
can get at present a beam in any desired direction and position.
The third course leads the beam to the analyzing system of high resolution which
consists of two magnetic beam analyzers with the deflection angles of 80 and 35 degrees.
A magnetic reaction particle analyzer of broad energy range type is now under construction. When a pair of quadrupole magnets Q- 2 is provided along this course beyond SW magnet as shown in Fig. 1 (3-2) the beam on the target in the scattering chamber is remarkably intensified.
We can normally obtain 0.3-0.7 tta beam of 3He ion with about 0.2% energy resolution, which corresponds to the deflected beam of 10-20 I-tA and focus it into thearea of 2 mm x 4 mm.
In the near future, quadrupole magnets (QS- Q10) and a distribution magnet; DS
will be provided.
(3) Beam Analyzing Magnet and Clearing Magnet
For a high precision measurement in the nuclear reaction study, there is an undesirable effect that the analyzed beam has low energy components due to resultant
edge scattering at the exit slits of the analyzer magnet. To reduce this effect, ananalyzing system with two magnets are proposed. One is called a main beam analyzing magnet and the other a beam clearing magnet.
As a beam analyzed up to 0.1% energy resolution by the main beam analyzing magnet passes through the beam clearing magnet and reaches the target in the scatteringchamber, the exit slit of the beam clearing magnet has only one baffle on the low energy
side to stop a part of beam contaminated by the edge scattering.
The characteristics of beam focusing system magnets are shown in Table 1 (3 -2).

13.5 kG

8cm

Effective
beam width

Maximum fieldor gradient127 em94 em dia.,
45°' 25°' 0°' -20°' -35°
bending angle

4

8 kG

15 em
where B/B0 = 2 x 10- 4(3 kG, 8 kG)

160 em

26.0 em wide
160 em radius,
80° deflection angle

5

H-frame,sectorEdge angle 90°

H-frame,semi -circularpole

Effective
beam radius

Deflection angle
and pole
dimensions

Pole gap (em)TypeBeam analyzing
magnet9 kG

160 em25.0 em wide
160 em radius,
35 ° deflection angle

6

H-frame,sectorEdge angle 90°

Beam clearing
magnetCharacteristics of beam focusing system magnets

Switching magnet

Table 1 (3 -2).

930 G

6cm

Circle of
6.315 em radius,
1.20 aa=1/2 gap

10.5

DoubletQuadrupole
magnet

.....
.....

Fig. 1 (3 -2)

Layout of the beam transpor t.

Gate box~ He/mlloltz coli

133-3. Circulation System of 3He Gas

T. Tonuma, S. Nakajima, and I. Kohno

The high cost of 3He gas necessitates the use of a circulation system to recover
any gas not accelerated or trapped in the cyclotron and to provide its purification for
re-use as ion source. The system consists of a rotary pump which has vacuum tight·
intake, exhaust, and a charcoal trap cooled by liquid nitrogen as shown in Fig. 1 (3-3).
And there are many hand and solenoid valves which are designed for protecting the circulation system from the leakage of 3He gas.
(1)

The characteristics of charcoal trap

An activated charcoal trap is used which adsorbs little 3He gas and much air at
the temperature of liquid nitrogen. We use 200 grams of charcoal, and the quantities
of 3He gas and air adsorbed by one gram of charcoal are given in Table 1 (3 -3 ).
Table 1 (3-3).

Adsorbed quantities of air and 3He gas into charcoal trap

140 cc STP/g

Room temp . (200C)
5.3 X 10 - 2 cc STP /g1.75 cc STP/g

0

Liq-N2 temp. (-183°C)
Air

A 3He gas flow required as the ion source is from 70 lus to 100 lus (about from 6
cc /min to 8 cc /min) and the rate of contamination of air must be below 5 %1) when
3He2+ is produced. Thus, the amount of air mixed with 3He gas in the ion source has tobe kept less than 3-5 Ius.
But it has been found from a preliminary experiment thatafter passing through the charcoal trap, the purity of 3He gas is maintained above
99.9% for a long time.
Therefore, in the circulation system it is particularly necessary
to keep the leakage between the output of the charcoal trap and the ion source below 3-5 lus.
(2)

Pumping system

The two mechanical booster pumps serve as the main backing for the existing
cyclotron diffusion pumps . Their output is connected to the 3He circulation system
placed in the control room (Fig. 2 (3 -3) ). The 50 1/min rotary pump in the circulation system, which is used during 3He operation, as a fore pump of the cyclotron evacuating system instead of normal one, recovers the gas and forces it to the ion source
through a charcoal trap dipped in liquid nitrogen.
Seven liters of 3 He gas S. T.P. has been consumed in five months. The consumption is mainly due to mistake in operation and exhaust in removing air already trappedin the charcoal trap. The leakage of 3 He gas in normal operation is negligible.

14

There occurs sometimes a trouble that, during operation, water collected in a gas
pipe near the charcoal trap changes into ice and chokes the gas inlet to the ion source.
Considerable amounts of substance showing activity of short life were found in the trap.
Reference
1)

N.I. Venikov and N.V. Starostim: Priboryi Tekhnika Eksperimenta, No.2, p. 25(1963).

Slow/eat~00=2S4>pipe-2tf>,

Fig. 1 (3 -3).

The diagram of the circulation system.

L

I

I

'"'--50.1./miftR.P~1.5*
2.5'1R.

2.5~

I
I

I

'lt.'lo.

- a.om____ ~

~

,

9.sm

The diagram of gas flow.

+---· -

- - - _ ___ _____..

JOIIL ___

·r--------------,.

. I

:I

I

.... '

:~~ J

-(1

~·:

_l·:· ~:LL .! -Fig. 2 ( 3 -3 ).

The Circu.rdtion
System.

=F-- ---

soo~..wnR.P.

32"D. P.

II

I

·Accder4tiftt Cha"'bertfte Ion Source

14"'D.P.

l

.I

1--'

CJl

16

3-4. On the Multicharg ed Heavy lon Source

I. Kohno, T. Tonuma, and S. Nakajima

The performance of a multicharged heavy ion source for the 160 em variable energy
cyclotron, has been examined by the bench test. A hot cathode of electron bombarded
type is used as the ion source. The charged state yield of ions and the source stabilities are investigated for various gases, i.e. oxygen, .carbon dioxide, and nitrogen. Ion
source construction s are shown in Figs. 1 and 2 (3 -4 ). An anode is made of graphitehaving a length of 8 mm without cooling. A cathode is made of tungsten having a sizeof 8 mm in diameter and 11 mm in length, and is shielded by graphite for reducing
thermal radiation loss. The source is operated at an arc voltage of 300 to 500 V andan arc current of 3 to 6 A, and the gas consumption is about 0.5 to 1.0 cc/min. The ion
beam extracted from ion source is analyzed by a 180° mass -spectromet er, and thecharged state spectra of carbon, nitrogen, and· oxygen ions, are shown in Figs. 3 and 4(3 -4}. The ratio of c3+, o3+ and N3+ to the total output are 15 %, 15 % and 20 % respectively, and that of N4+ is about 2 %.
The same type heavy ion source has been installed in 160 em cyclotron and a defleeted beam 2 llA of N4+ was obtained, but operation of this ion source in the cyclotron
condition is some what unstable. The reason is now under investigation .
filament
power supply

5V. 200A

electron bombarding
power supply
ZkV. 2A

cathode8

arc power supply t-8.;;;..__~
1.2 kV. lOA
2A ......J(f)
6 kV.
__.___ _

ion accelerating
power supply
40 kV. 200mA

anti
cathode

L.......-----------8
Fig. 1 (3-4).

extraction
electrod'e

scale
0

Ion source and block diagram for power supply.

50mm

Fig. 2 (3 -4).

Ion source for bench test.

(1) Filament lead (Cu), (2) Cathode lead (Cu), (3) Acrylite plate, (4) Gas inlet (Brass), (5) Coolingoil, (6) Spacer, (7) Insulator for high-tension, (8) Insulator for extracting electrode, (9) Dischargechamber, (10) Cathode, (11) Extracting electrode holder, (12) Filament.

0 20 40 60 80 I 00 mm

scale

m

J

:--nl

j:

1--'

-....]

18

~A

~A

600

600

N2+

~

t.n

~

300

400

>
0
00
M

N+

XlO

N4+
N 3 + ·· )(10

cz+
c+

LL

A

Fig. 3 (3-4).

200

G.~+

200

1/

v

"""JIJ
..

~

jJ

A,.,-

Spectrum of nitrogen ion beam from nitrogen gas discharge.

~

80

60

40

X/ol

20

Fig. 4 (3 -4).

i ' c z+1

Xlo

X 10

Q 2+

Spectrum of oxygen and carbon ion beam from C02 discharge.

19

3-5. Design of the focusinq Magnetic Channel

Y. Miyazawa, T. Tonuma, M. Hemmi,
0. Terajima and M. Odera( 1)Introduction

In the IPCR cyclotron the ordinary magnetic channel which shields the fringing fieldof the main magnet along the path of beam is not used. Proposed maximum field for theacceleration of heavy ions is very high, and it is expected to be difficult to maintain adefinite orbit with the ordinary type magnetic channel for the wide range of variableenergy. At present, therefore, electrostatic ally deflected beam travels a very long
path in the fringing field without magnetic shielding and is extracted from the acceleration chamber port azimuthally 180 degrees apart from the entrance of the deflector.
Naturally the beam spreads out radially. Transversal profile of the beam wasmeasured at the early stage of machine conditioning and is indicated in Fig. 1 (3 -5).
As is clear in the figure the beam spread is rather rapid in down stream. The adverse
effect of the beam spread is twofold. Firstly, owing to the finite acceptance width of
the beam focusing system only a small amount of the deflected current blows into thebeam piping. Secondly, the admitted beam has a rather large divergence. It is equivalent to have an object point very near to the 1st focusing quadruple -magnet. To get asmall- sized image of good quality a small portion of the extracted beam has not to bediscarded in the beam focusing system or strong focusing ability is needed.
To avoid these difficulties several methods are proposed. The machine is alreadyvigorously in use, and the beam handling system has a fixed configuratio n. A correcting means is not permitted to alter the beam orbit greatly. The cyclotron and thefocusing system have a number of parameters to be adjusted. Therefore, these means
should not be a burden to the operating crew much more. Fallowing is the one which
has finished the model study and the preliminary calculation of the orbit. It will be
installed in the accelerating chamber this autumn. It will not change the center orbit
but make the present beam profile to shrink radially and reduce the radial divergenceat the exit of the accelerating chamber. This needs little adjustment in the operation
once set.
(2)

Concept of B constant magnetizatio n and its application to a focusing
systemMagn~tization of an infinitely long bar of circular cross section can be analyticallysolved.

Magnetic induction at the outside of the bar is represented by- 2
yz .
By- R (y2 + z2)2
Bz = -R 2

Bo

(1)

Ba

(2)

y2 _ 2 2(y2 + 2 2)220Here B0 is the uniform magnetic induction originally present. Y and Z axes are as indicated in Fig. 2 (3 -5 ). In Fig. 2 (3 -5 ), field pattern given by eqn. (2) is shown. Magnetic induction in the bar has only z component of 2 B0 in strength and is constanteverywhere. This is the so-called B-constant property!), namely, the bar will notundergo local saturation, and the field pattern that it gives will not change until 2 B0
exceeds the magnetic saturation strength of that material. Therefore the focusing property of a system composed these bars will not affected by external field.
We use a simple composition as shown schematicall y in Fig. 3 (3 -5 ). XY -plane
coincides with the median plane of the main magnet. The field shape which the channel
gives can be easily synthesized from curves of Fig. 2 (3-5).
It gives radially increasing field of almost constant gradient.
When the channel is placed in such a way that the point of J B = 0 is coincident withthe center of the beam, the beam is focused radially toward the beam center and is defocused vertically. ·The focusing property is determined by the gradient or negative"n" value. Of course, the field of the main magnet is not uniform at the fringing field
and the field gradient must be recalculated using the value of main magnet field distribution. But since the gradient of main magnet field at each bar does not change largely
along the beam path, the recalculation is not difficult and the beam trajectory is easily
obtained.
Also, the relative distribution of fringing field of this main magnet itself does notchange very much against a wide range of its excitation owing to its special pole profiles. 1) And so, once the field pattern and the focusing properties of the channel are
determined, the trajectory of the particles is essentially invariant against the excitation of the magnet as long as the bar is not saturated.
This channel gives the disturbance or the bumps to the main field. Its quantity isalso given by eqn. (2). By choosing the size and location of bars properly, the effectcan be reduced to the order of n x 10-4 in the main field.
(3)

Results of model study and calculation of beam trajectory

One -third scale channel is constructed and tested in the pole gap of a small magnet
to make clear saturation property and finite length effect. Relative value of fieldstrength is directly obtained using two Hall Methods developed in this laboratory2) ,which simplify the measuring procedure. Fig. 3 (3-5) shows the results measured.
Field pattern at 40 mm from the end of the channel maintains a constant gradient of
24 %per em from low field to 1.3 Wb/m2. Calculated gradient is also plotted in that .
figure. Saturation of iron is expected to begin earlier at the lower field near theend than in the middle of the channel. Really, the constant gradient can be maintained
until B0 becomes 1.0 Wb/m2 even at the end. Since the strength of fringing field at the
point where the channel is to be placed hardly exceeds 1.0 Wb/m2, relative field gradient in the channel is practically constant for any excitation strength of the main
magnet.
Trajectory of the beam is estimated for the uniform channel, the structure of whichis shown in Fig. 4 (3 -5 ). As n -value is not constant throughout the channel, the calculation is made by dividing the channel into several sections and constructing conversion
matrix for each section. Particles which are 1 em apart and placing at an angle of tothe center trajectory at the entrance of the channel will move in the trajectory which isparallel to the equilibrium orbit and less than 3 em apart from it, after traversing

21

through about 80 em of the channel. Of course this length can be reduced using acertain different configuration. Improvement of this procedure and the method of supporting this device near the poles are now under examination.
Reference
1)
2)

H. Kumagai: Nucl. Instr. and Methods,~~ 213 (1960).
M. Hemmi et al.: Reports I.P.C.R. (in Japanese), 39, 170 (1963).
Proc. Intern. Symp. on Magnet Technology, p. 472 (1965)(Stanford) U.S. Dept. Commerce, Sp'r ing field, Virg., U.S.A.

-- -*- Thespred.dctbeo.m when tne masneticchannel-

is not used
ThespreddOfbeama:fter setting oftllemd9netic
chdllrtel
0

10

20

30

'----'-----'--------' CITll

Fig. 1 (3 -5 ).

Measured beam spread and the expected focusing
effect of the channel.

22

2.0

3.0

2.0

1.0

+0.4

-0.2

-0.6

-0.8

-1.0
2

0

Fig. 2 (3-5).

3

4

5

6

7

Field induced by an infinitely long bar (tt=oo)placed inthe uniform magnetic field.

8

23

X
t-------...J·~

(a)

-JS

-10

-5

- - - - - - - - - - - 30 ---------~(b)---{)--- - - trw •Fig. 3 (3 -5 ).

(a) Schematic diagram of the focusing channel.
(b) Field distribution in the median plane of 1/3
scale magnetic channel.

Fig. 4 (3-5).

o......-j

90 _ _

50 mm

T

-§~

--c:::rII

The design of channel indicating the position
adjusting mechanism.

rE------@ 304> ~ott iron bar

CD Bedm path.

..::::::::::3--

100 mm
L__j

o

~ V)~

I Il
--~

- -If{

'"~

!:?~

n.!

~

25

4. ACCELERATOR PHYSICS

4-1. Initial Motion of Ions

Y. Miyazawa, T. Tonuma, S. Motonaga, M. Hemmi,
A. Shimamura, T. Inoue and T. Karasawa

We began to study a beam trajectory in the central region. The IPCR cyclotron
has two dees connected to form shielded Lecher line resonator and an ion source
holder is inserted on the center line between dees. An usual beam probe, moves on
7.5 degree line and measures the beam current from 20 em radius to maximum radius
and that of deflected beam.
We made also a special beam probe. It can measure beams from the neighborhood of ion source to about 20 em radius. A 2 mm diameter tungsten wire, vertically
70 mm long, moves along the center line between dees (A-B line in Fig. 2-a (4-1)).
The radial distribution of the beam is measured in a form of differential trace. The
tungsten wire is not cooled for the sake of simple construction and it can withstandlarge beam current above several rnA. One of the radial plots is shown in Fig. 3-a(4-1). Beam bunch and turn separations are shown which linearly increase with deevoltage at early turn. When ions are reversely injected to east dee (usually to westdee), a beam distribution along theA-Cline in Fig. 2-a (4 .;: 1) can be measured. The
radial distributions on this line are expected to be spread broadly and one of the experimental results is shown in Fig. 3- b (4-1).
The electric and magnetic fields precisely determined in the central region arenecessary for beam study and the electric field distribution between dees without feeler
has been solved analytically. A configuration of the ion source and feeler, which are
now used, is shown in Fig. 1 (4-1) and we tried three types of configurations; usual one
with feeler, without feeler and with grid at the edge of the feeler. The distance d fromthe ion source to the first turn, in the case without feeler and injection to west dee, andthe normalized dee voltage are shown in Fig. 2-b (4-1). Proton and 3He+t are accelerated and dee voltages are divided by m/q. Linear dependence and agreement withcalculation are shown.
A differential beam probe was used to measure the radial beam distribution £rom
30 em to maximum radii but individual turns were washed out by poor regulation of dee
voltage. The dee voltage stabilizer will be installed this autumn.
A three-finger probe was used for vertical distribution of beams from 20 to maximum radius. A large beam loss from 20 em to 35 em radii was found. The origin of
the loss was searched but we cannot make it clear at present.

Fig. 1 (4-1),..

The central cyclotron region, showing the ion source, feeler, and dees.

,,:.; .;_.. ~i~ -,4:-..r~·~" ,~-- ~>. .... ~"· .. ;. _;;EAST DEE

Ln0.:. .:,:.·

to..)

0.

0

( b)

8

- ~/

1

EAST ..

DEE~ .

.f

WEST DEE

~

~

u

~

)(

~

I
)(

I

....,

X

..Jl

b

)(

•

.

I

• .:!:'

d

~

l

(a)

20

30

40

50

(~V)

Fig. 2 (4-1)(a) The case of west dee injection.
(b) The distance from the ion
source to the first turn vs. the normalized dee voltage.

CD

Q)

tO

~

~)

::::5

~

,_

<lJ

~

'-'

0

1

0

ll

~I

s::
::::>

~

,--....

5

1

Fig. 3 (4-1)

~

I

5

'

,

(_(1)

10

I

(b)

__,

....

J5

1~

15

.....__...-

20:---r=::

Beam density vs. radius. (a) In the case of west dee injection.
(b) In the case of east dee injection.

,

10

~

1 (om)

25

25

(am)

t-.)

CX>

29

4-2. Investigation on Electromagnets
Hysteresis Effect of Field Distribution
S. Motonaga, K. Matsuda, N. Nakanishi,
M. Hemmi and H. Kumagai

Design of the electromagnets used for an accelerator and in a nuclear magnetic
resonance research has been extensively developed in these several years.
For many experiments in physics it is necessary to have a magnetic field of thehighest degree of homogeneity in spite of variations of the magnetic field strength.
Such an electromagnet can be designed by using properly shaped magnetic pole pieces
which make saturation effects minimized at any edges or sharp corners of the pole,and has been successfully installed in a few cyclotrons and many experimental equipments),2,3,4)
If usual rectangular or cylindrical pole pieces are used, the edges of such polepieces become saturated and the relative permeability varies in the different parts ofpole pieces even for fairly low field. These effects spoil the homogeneity of the fieldand change the distribution of the field with the variation of magnetic field. It is the
purpose of this study to show experimental results which illustrate how hysteresis
effects of iron affect the magnetic field distribution ~ven at a low field strength.
The hysteresis effect in the magnetic field is well recognized as due to the remanent field and as resulting from the difference in values of field strength in increasing
and decreasing ampere-turns. However, the change in the field distribution due to thehysteresis effect was not yet analyzed in detail. This problem becomes serious whenhigh homogeneity is required in order to make higher resolution experiments of charged
particles from nuclear reactions.
The hysteresis effect of about 1 x 10- 3 has been observed by the measurements ofthe field distribution of transporting and analyzing magnets for the cyclotron beam of
0.3 and 0.5 Wb/m 2 in field strength. In these magnets, the pole shape is nearly cylindrical or rectangular as shown in Fig. 1 (4-2), and thus the magnetic induction in thepole is not constant. Therefore it is thought that the hysteresis loop of iron is not thesame at different parts of the pole and that the hysteresis effect appears remarkably inthe field distribution in the air gap.
A typical result of measurements is shown in Fig. 2 (4-2). It is seen that the hysteresis effect appears near the edge. When the exciting current of the magnet is decreasing, the field near the edge is higher than that when it is increasing, which amounts
to about 1 x 10-3 and 5 x 10-4 at 0.3 and 0.5 Wb/m2, respectively.
To examine a variation of the field distribution due to such a hysteresis effect,measurements of the field distribution have been made by attaching the iron pieces of aB-constant profile to the entrance side of the pole as shown in Fig. 3 \4-2). Results ofthe measurements of the field distribution do not show remarkable improvement for thehysteresis effect. However, when a magnet pole is shaped after B-constant curve inall sides, it will be expected to approach a constant distribution of the magnetic induction in the pole iron and to reduce the hysteresis effect. Another reason for inhomogeneity depending on excitation is considered to come from the inhomogeneity of raw

30

material. We are intending to continue this kind of investigation for the further improvement of high resolution electromagnets.

References
1)
2)
3)
4)

H. Kumagai: Nucl. Instr. and Meth., £,213 (1960).
C. M. Braams: Nucl. Instr. and Meth., 26, 83 (1964).
A. Huber: Nucl. Instr. and Meth., 33, 125 (1965).
T. Karasawa, et al~ : Proceedings of the International Symposium of Magnet
Technology 1965.

1------ - 1000 - ---ta)

Switching 111.gnet
bending angle 45:2s:o:-20:-35"
maxiJnwl !ield 1.35 Wb/a•e:rtective beaa radius 1.27 a

Fig. 1 (4-2)b)

Beaa a.na.L;yung aagnet
defiection angle so·
JII&Xillua !ield 0.8 Wb/a'~­e!!ective beaa radius 1.6o aGeneral view of the switching and analyzing magnets for the IPCR
cyclotron beam.

Switching magnet-'"'/_::·)...-~

a{t~r fii•"JtwtiJI.tiDII/.:"'\•-•• ........ ---;:
\
,j/-~

~

a-o.s

\l

·I

·~·~A -------./· ),.""' ','-.

.,., .u...."4fl"

r

T

I

.,III

.~/

.

/

I

/

,/''

~-T.o•~~

/

I

I
I

I

I

I

I

I
.I

. \ IXIO-l

l

•y,

b)

Bo : 0.5Wo/Jitz

Bo : 0.3Wo/•z

Beam analyzing magnet

SILrtACe 0/', ___ __'/".

·-..............

\

-,
\

\

o---o. •/•'

I

I

1

IXIO-l

T
~

'T

Tj
4~. .

l

l

.I

alter d£1Uf1l'ttr.tiDA -·~\"---·" ____...

- ---, .....o-as•/r

w botto• ,o~e

~~I

\

\

~I

"-.__ .

.'

tffect do to Ue Jttehdllicdt ~rror on tM

Variation of the field distribution along the beam path in air gap
depending on the cases of increasing and decreasing the field strength.

...._----·-- .

--~,('~- .

Fig. 2 (4-2). ../;-_,""""

B.' tOIPb/••

L---------------~~~
EtiJ~

I

I

.(--/

{

r·~· ~;.- ~,Bo : 0.5 wf>h,z

a)

.....

(J.j

32

Beam ana.1:y zing magnet

With irolt ieceso---aswt>/,.2

pole pieces

pole pieces
red ironpil!Ces

Fig. 3 (4- 2)

Improv ement on the field distribu tion by attachin g the iron pieces to anedge of the pole.

33

5. NUClEAR PHYSICS
Scattering and Reaction

M. Odera, I. Kohno, S. Takeda
and S. Na~ajima

Differential cross sections of 21.3, 24.2 and 31.5 MeV 3He particles elasticallyscattered by 27 Al in the angular range 15°'""'"' 1650 have been measured, in order to obtain the accurate optical model parameters of 27Al. Differential cross sections for(3He, a) reactions were also measured.
An extracted 3He beam from 160 em cyclotron was energy analyzed, led into the
75 em scattering chamber and focused on a target in a size of 1 mm x 8 mm. Theenergy resolution of the beam was 0.2% and the intensity was about 0.3 ttA. Thicknessof target was 350 ttg/cm2. Scattered particles were detected by silicon surface barrier detector and over all resolution was about 70 keV. In some angles the combination of the thin transmission type and the thick one was used to discriminate different
kinds of particles. Fig. 1 ( 5-l) is a pulse height spectrum. Excitation energies ofresidual nuclei are shown. Fig. 2 and Fig. 3 (5-1) show the differential cross sectionsof elastically scattered 3He and of a -particles. Distribution for the angles smaller
than 100° of center of mass is in good agreement with hitherto-publish ed datal). But,
backward angular distributions of elastically scattered 3He are apparently different
with incident particle energy. At E = 24.2 MeV, backward rise is prominent, but at
E = 31.5 MeV this is not seen. Forward angular distributions of various a -particles
are very similar with each other for the peaks shown in Fig. 1 (5-1), except for that of
0.418 MeV level. However, there is apparent difference in the backward distribution
as shown in Fig. 3 (5-1) in the case of transition to ground and 1.059 MeV state of 26Al.
These results suggest usefulness of the measurement of the backward angular distribution for the study of reaction mechanism and level structure.

Reference
1)

D. J. Baugh, G.J. B. Pyle, P.M. Rolph and S.M. Scarrott: Nuclear Physics, A95,
115 (1967).
V. M. Pankratov and I. N. Serikov: Soviet Phys. JETP, Q, 604 (1963).

u

0

:::;)

....z

(/)

..........

u

z
<
:r:

z

l.J.J

... : ,

•

J

il

~

C'\i

('J

N

•

~
II

•• •'

r

~ •" •: 't·... •....
I

B.ASTIC

....•

'h.

Fig. 1 (5-l)

.. •
''I(

·..

CHANNEL NUM

1000

"

J )\ l
·\

I

,'

I
.1\·
•' • •
1100

·

·:·1

BER

II

1'

N

1:.'--~l,.o. y

J

•

I.I

. ·, ..

1200

J' .

sn
o

01

t,,_......,....,._•.., t;r,~9lat.= 30°

E.te3 = 24.2 MeV

11"1<'1 0~~ C'\i"''t~.£>

to-t--

3l- \!ll, a .J I~.. .
•)).7

AL tHePulse height spectra of 3He and a -particles obtained at ()lab. = 30°
from the bombardment of 27Al with 24.2 MeV 3He particles.

.) '

I 1
J• ' • •,J • \1.~· ru :. :,(. . . III\ Jrtn ••I i \\ \···... \"t · • .. ' I.fl\

:j ..

'·!

.:: ·· · · . .. ·• • •,.. •.

('f"')-

en tN ""~

4.D

800--------c~900100.....JlOO

300

Xt/100:...

r :· .

d

0

tJ)()

~
~

35

27

Al +He•3

ELASTICSCATTERINGf~e3 = 24.2 MeV

f

EHe3 = 31. 5 ~1 e V

'I
\

I

\

I

\~

lQ~L--L--~~30__J_~~-6LQ--L-~--9~0~~~--~12~0--~~~~~--~~180
CENTER-OF -MASS ANGLE (deg)Fig. 2 (5-l)

Angular distribution, expressed as a I a R, for the elastic scatteringof 24.2 and 31.5 MeV 3He particles.

36

It Al27(He5,a.)Al26

fI I I f,-...

tn.........

..0

E

1 -

tti t

z

I

.....

3

w
(/')

2

iI

(/')

_J

<

~

'tIt

ht

(/')

u

i
II

u

0
0::

10_, -

J !

i
I l

t

7

z
w

3

-

2

w

t

I

I I

i

~

~

-

It •Ifill

5

0:

-

t

1

5

..........

0I A~He ,~)AL~

t

II

1

Ew=24.2MeV
1

0

l I

I
lI

1
I

t

i

JC)2r-

HIt

I

II

-

f

7

5

i

3

Ill

2

10_,
0

Fig. 3 (5-1)

I

I
30

I

I

I
60

I

I

I
90

I

I

I

I

120

I

I

I

I

150

CENTER-OF-MASS ANGLE(deg)Angular distribution of a -particles for the 27 Al (3He, a )leaving 26Al in the ground and third excited states.

26Al reaction

37

5-2. Elastic and Inelastic Scattering of 3He from Ni Isotopes

H. Kamitsubo, T. Fujisawa and T. Wada

The investigation of inelastic scattering gives a detailed information on the excitation
mechanism and on the properties of the excited states. In the present work the elastic
and the inelastic scattering to several lower states were measured over a wide range ofenergy. An external 3He beam was energy analyzed, led into the 75 em scatteringchamber and focused on a target in the size of 1 mm x 2 mm. The energy resolution of
the beam was about 0.2 %and the beam intensity was about 0.3 ,u A. The scattered particles were detected by a single detector system of 1,000 J.t surface barrier unit, or acounter telescope system of 50 ,u transmission unit and 1,00011 lithium drifted unit. A
small permanent magnet was put just before the detector system to reject the secondary
electrons from the target. The overall resolution was about 70 keV without target
thickness effects.
Targets of the separated isotopes were prepared by electrochemical deposition.
An ambiguity of thickness due to target inhomogeneity was avoided as follows: forward
angle scattering cross sections of 3He were measured at 14.4 MeV and compared withcalculated values of Coulomb scattering cross sections. Target thickness was thus
determined within an accuracy of 5 percent.
Data were taken from 150 to 1700 at 2.5° and 5° intervals. Typical angular distributions of elastic scattering from 58Ni are shown in Fig. 1 (5-2) where differential
cross sections are devided by the corresponding Rutherford cross sections. A spectrum of the scattered 3He from 58Ni is shown in Fig. 2 (5-2). As shown in the figure,levels at 1.45, 2.46, 3.04, 3.26 and 4.45 MeV are excited. Angular distributions ofthem are shown in Fig. 3 (5-2). A phase relation between three cross sections canclearly be observed. The measurements at other energies and with other targets are
now in progress. The DWBA analysis of these data is being performed.

38

a:::-

~
\!)

to

58
~

••

58

3

Ni( 3 He I He )

Ni

••

~~

• • •

•
•

1.0 ~
• ••

•

24.1 5MeV.

•
•

• •

•

•
•

• ••

• •

•
•

Ql-

•

•
••••

•

••
•

• •

•

••••

•

•

•

•

•

•

00.1 t-•••••27.64MeV.

•

••

•

• ••
J

I

•

• •
•
•

• • •
• • • •.001 1--

I

Fig. 1 (5-2)

I

I

I

Angular distributio n of the elastic scattering .

I

u

100

200

:::::>
0

z

~

Vl

300

.f.\
.. ,~I \.··· ·y ··.··

t'~

N

I

.
I

..q~

~

"-'

('()

I

-....

3

58

e = 35°

I/-.:::t~ ~<.0...........

+C'\J

E = 27.64MeV

3.

Ni ( He , H~ ) Ni~

N.........

"'':t

+

....--.._

500
Fig. 2 (5-2)......
. ·.

• J
...
.....

I

ol

-J

0
l.U

t;

u

X

\-

0

~o

j \

r
650

r

.i .
...

.i
,., AJ•.. ~:... .)...\~! 'I \

600
CHANNEL NUMBER
Pulse height spectrum.

550

j\·.

-u

N

"'l::t...-.........
\.0

C'J..........

+-

l .\ . ..

·. ·.·. I.N'-·...·._./\.- .,.../ .. / \.....(\·:· .. ../\
• ··.10 \f·:.. . ('.

58

\.0

w

40

1.0

\
\

0.1

0.01

Elastic
0.001(a-/ CJRUTH)

0

Fig. 3 (5-2)

Angular distribution of the inelastic scattering.

41

5-3. Elastic Scatterings of 3He from Ca

K. Matsuda, Y. Chiba, N. Nakanishi andY. Awaya

The angular distribution of the elastic scattering of 3He from natural calcium
target was measured at four different incident energies, using the 75 em scatteringchamber and a solid detector telescope. This experiment was planned with two purposes. The first is the comparison with the elastic scattering of alpha-particles from
Ca. The alpha-particles show an anomalous behavior at a backward angle, which cannot be explained by the simple optical model analysis. The experiment with 3He, whose
wave number corresponds to that of the anomalous alpha scattering, was considered as
helpful to elucidate this strange effect. The second is to search the optical model
parameters for the 3He scattering. Recently, there have been published so many reports on the angular distribution of elastic 3He and on the optical model analysis for
3He. Few works, however, were performed on the energy dependence. Angular
distribution at several different energies seems to be useful not only for the determination of the energy dependence of parameters, but also for the estimation of their magnitudes themselves. There is, for example, a well- known ambiguity on the real welldepth.
The incident energies were 25.0, 30.0, 18.8 and 34.5 MeV. For the former twoenergies, the beam passing through the so-called lst course (See 3-2) was used. In
this case, the emitted particles were detected with a single surface barrier detector(OR TEC). It was found that the contamination of alpha -particles fro n1 the reaction of
40ca (3He, a ) 39ca was not so small and at some angles the errors became very large.
The poor resolution of the beam was then considered to be improved. Thus the analyzed beam (the 3rd course, see 3-2) was used in the experiments for the incident
energies of 18.8, and 34.5 MeV. The scattering chamber had no front slit and a quadruple lens made an image of the defining slit of beam analyzer on the target. The
dimension of the spot was about 3 x 6 min2 and the energy resolution was about 0.2 %.
The obtainable intensity of 3He beam in this case was 0.3-----0.7 Jl.A. The self-support
targets of calcium were made by evaporation and the thickness, which was aboutl mg/cm2, was determined from the measurements of weight and area .
The results are shown in Fig. 1 (5-3). There was found no special backward
anomalies in contrast to the alpha scattering. Optical analyses, using the INS code
DWBA- 2, have been tried. Very good agreements have not yet been obtained, since
the automatic search routine is not available. Some of the results are shown in Fig.
2 (5-3). The optical-model parameters are those of Bassel.

42

a·

1

••••

•

•

4o Ca. (3He••• •••

EQa.stic• • •••

10°

00

••

0

• •••• •

•

0
0

•

• ••

0
0

• ••

E = 1 8. 8 MeV
•

••

ooo

•
•

0

10°
~

~

•

••

~

0
0

••• •

~

~ 10°

......__./

~
L'

••

0

9¢ 999 0
00

0

0

oo
0

oo

0

•

• •

0

~

•• •

•

~

-o

00

•

• •

0

00

ooo

••
• ••
•

••

0
0

0

MeV

31

E

•

0

0

......__./

0

00

0

0

0

0

0

••

•

0

~ 10-l

0

0

0

0

d

0

0

••

••

0

¢0

0
0

0

0

• •

• • •

•

• • •

•

0
00
0

0
00

0

E= 34.4 MeV

0¢9¢¢9¢

0

¢9

9 0

0

9

9¢

0

¢¢ ¢¢ ¢¢
9¢¢ 9 ¢

0

Q 9

0

¢

0

¢

9

20

40

Fig. 1 (5-3)••
0

E = 2 5 MeV

0•• • • •• •

0

0

•

0

•

•

• •

0

••
•
•

-o

•

•
ooo

0

a:::
............

He)

SClltterin~

•

00 0
0

3

60

80

100

120

140

160

Angular distribution of the elastic scattering.

0

43

4

°Co. ( 3He, 3 He) E.Qastic Scatterin~

v
176.9

w

Yo
15.47 1.164

rc

lr

1.617

ao

ar

1.164 0.654 0.975

E = 18.8 MeV

•

•

•••

/

0

0

I

0

0
0
0

I

••

\
\

I

• •

I
I
I

/\

I

\

I

••• •

20

40

Fig. 2 (5-3)

60

80

100

8c.M.

(d.e~)

120

140

160

A preliminary fit of the angular distribution.

•

44

5-4. Coulomb Excitation with Alpha-pa rticles

A. Hashizum e, H. Kamitsubo , T. Inamura,
Y, Tendow, T. Kato, and K. Matsuda

The method of Coulomb excitation has been used extensivel y to explore the properties of the low-lying excited states. Especially the collective states of even-even nuclei
have been widely studied by this method. In general the energy levels of odd nucleus
are more complicat ed than those of even nucleus and the improvem ent of the energyr esolution of the detector is important to distinguis h the small difference s of transitionene rgies. We r epeated the investigat ion of the Coulomb excitation of 197Au by alphaparticles employing a lithium drifted germanium detector for the observatio n of gammarays. This nucleus has been studied by many authors and the transition s of 77, 191,
278 and 549 keV are known.
Since the transition probabilit ies and the low-lying energy level structure of 181Ta
are well known, this nucleus was chosen in the study as a check on the technique used.
Other targets, natural silver, palladium indium and platinum has been tested.
The beam of alpha -particles accelerate d from 11 to 15 MeV have been transporte dby an ion optics system in a small irradiatio n room and focused into a spot of approximately 1 cm2 in area. The beam current obtained on the target was about 0.1 ttA.
Gamma-r ay spectra were observed with a liquid-nitr ogen-cool ed lithium-dr ifted
germanium detector of dimension s 10 mm in diameter and 4 mm in thickness, coupledt o a low-noise pre-ampli fier (TMC 100 c). The pulse heights were analyzed by a 1600
channel pulse height analyzer. The over-all energy resolution of this system was 7
keV (FWHM ) for the 662 keV gamma-ra y. The detector was placed at an angle of 70°
to the direction of the beam, at a distance of 87 mm from the targets. The targets
we re placed in a vacuum chamber made of brass. The thickness of the window was
1.5 mm. The thi ckness of the detector window made of aluminum attached to thecryostat was 1 mm.
F igs . 1 and 2 (5-4) show the typical gamma-ra y spectra for Ta and Ag excited with
11 MeV alpha-par ticles respective ly. For Ta, the cascade gamma-ra ys, 165 keV and
135 keV, from 11/2 +state at 303 keV excited by E2 are completel y resolved. For
Ag, fo ur prominent peaks are observed. The 325 keV and 427 keV gamma-ra ys are
originated from 107Ag. The 311 keV and 418 keV gamma-ra ys are emitted from
109Ag. The origin of weak gamma-ra ys observed at 274 keV remains uncertain.
F ig. 3 (5-4) shows the gamma-ra y spectra for Au excited with the same energy ofalpha -particles . The known excited levels in 197Au are shown in Fig. 4 (5-4).
The 77, 191, 279 and 549 keV gamma-ra ys have been observed by previous Coulomb
excitation experimen ts. In addition to these gamma -rays, 93, 155, 199 and 267 keVphotons are observed. The 267 keV gamma -ray is the cross over transition from 268
keV to ground stat e. It is likely that there exists the 270 keV transition from 539 keVstate to 279 keV state but the correspon ding gam ma -ray is not resolved. The 199 keV
gam ma - r a y is the transition from the 279 keV s tate to the first excited state. It is
possible tha t 155 keV gamma - r a y is the photon observed by Friesacke r and Roy in the45

study of 197mpt decay. But this gamma -ray has not been observed in the more detailed
work of Haverfield et al.
For the levels in 197Au, Braunstein and de-Shalit have proposed a core excitation
model in which the quadruplet (1/2, 3/2, 5/2, 7 /2) arises from the coupling of a 2+ coreexcitation with d3/2 proton. Kisslinger and Sorensen have also discussed these levels
from the point of view of the shell model taking into account of the Q-Q interaction.
The determination of E2 transition probabilities may become the sensitive test of thesemodels for 197Au.
Table 1 shows the relative gamma.:.ray intensities of these thick targets at 700.
These intensities are normalized in each spectrum to the most intense gamma -ray.

..•
>

,....

·Ill

-

l

To

>

•

...:

_J

w

z
z
<{
:r:

>

•

3

...:

10

,0

l

u

'

U)

1-

z

::)

0

u

...

I 02.

. ••··· .

. ... .....
.

...

10

4

0

100

200

• •

. . ...

•

300

CHANN EL NUMBE R

Fig. 1 (5-4)

Gamma-r ay spectrum of 181Ta.

. .. .. .
..

400

47

Ag
·.
10

4

·.
·'\.

·········..

····......

>>

••
....

···..

-.n
-(\1

..

..J

·...:.-·...

w

z
z

ii

>>
••
......

...

H

.\J'

103

<l

:r:

u

..........
CJ)

.

CDI'-

.,.

-N

i

\. ..

t-

·

..... .. ,·. ·.

z

:::>

0

u

10

2

·.· ..··~ .•.· ·. :: . .•. •, ..

.··.·.:...• .·. ... ·: .. ·. .· .
'

. . .

-

.

. ··:::..· ,··:·..=··..·· • •......

.. •,.. .: .

··. ·.

10

0

100

200

CHANN EL

Fig. 2 (5-4)

300

NUMBE R

Gamma-r ay spectrum of Ag.

400

48

>.,
~

_J

>

w
z
z

~

e

3

~·····.f\;

10

-~

<t:
I

>>
..: ..:

.....
....

4J)

N

-

I

cncn

H

~

t

(.)

en
t-

::::>

•

.M.

01
~

•.

z

0

>

- ~:_,:._... l t.........

It)

~

..

....·.'·4·. •··•. ·••

102

.. ·

u

~

' .. . II... . j... :·~. :. ·. ..·.. . . ....·

.

.. ..
.

,
•' I

10

.

0

100

200

.' . . '.

300

CHANNEL NUMBER
Fig. 3 (5-4)

Gamma -ray spectrum of 197Au.

..

..
. ...

400

49

.
'I

7/2

5't9

jl\

1

J

11/2

409

I
I

'

5/2
3/2
1/2

279
; I'

l

312

v

,~

268

17
0

197
79
Fig. 4 (5-4)

Table 1 (5-4).

Au
Energy levels in l97 Au.

Relative intensities of gamma rays

a-ray energy(i~ ~v >

181

Ta
Ag

(-n~t&4 r~J )

197

Au

137
165
30 I
3 I I
325
418
4 27
75
93
155
I9 I
199
267
277
549

reI ative lntensit~

100
23
I 8
80

73
I 00
7 8
1.6
13
2.3
9.8

100
6 6

50

6. NUCLEAR PHYSICS
Nuclea r Spectro scopy and its Applica tions

6-1. Measur ements of Internal Convers ion Electron s

Y. Tendow and A. Hashizu me

Recently a high precisio n, high resolutio n air- core beta -ray spectrom eter has been
complete d in the cyclotro n laborato ry and its perform ances and characte ristics are now
under extensiv e examina tion. The spectrom eter was originall y intended to be used forsroutine work with a resolutio n of .-...... 0.05% region. But this resolutio n already surpasse
by
cases
some
in
the values attainab le with iron- core spectrom eters by five times or
ten times. Accordin g to prelimin ary data, a,..,___ 0.03% FWHM resolutio n in momentu m
can be attained constant ly without special efforts using the 661.59 keV transitio n in
137mBa. The source was made by a liquid drop depos-itio n method.
It is now possible to study internal conversi on electron s in a more detailed mannerthan previous ly known. In conseque nce, a possibili ty of obtaining new informat ions is
promise d in nuclear spectros copy. Among them, the L-subsh ell conversi on coefficie nt
ratios are especial ly useful for removin g ambigui ties in nuclear spin parity assignm ents.
The results of precise measure ments of subshell ratios and transitio n energies together
with some necessa ry coincide nce data are enough to establish a reliable level schemein ordinary cases. Precise measure ments of subshell ratios also give a means tosearch for fine nuclear structur e effects on conversi on process, such as the penetration effects and electric monopol e transitio ns.
Prior to routine operatio ns, the spectrom eter have to be calibrate d with several
standard conversi on electron lines. The 411.795 keV transitio n in 198Hg was used tocalibrate the potentio meter readings with respect to magnetic rigidity Bp for electron s.
The source was made by evaporat ing natural Au on an aluminum foil and irradiati ng
with neutrons of 2x lol3 n/sec/cm 2 for a week in the JRR-2 reactor of Japan Atomic
Energy Researc h Institute . Source dimensio ns are 0.3 mm in width and 20 mm inlength. The source thicknes s is difficult to estimate but it may be presume d to be lessthan 0.1 microns .
The K, LI, -Ln and Lui line measure ments were made in the current range 3 (from
8A to 32A). A typical line spectrum measure d is shown in Fig. 1 (6-1). The ultimate
resolutio n attained with this source was 0. 026 %with a baffle of 20 mm and a slit of 0. 25
mm.

51

Table 1.

B,o
K

LI
LII
Lui

(G ·em) l)
2222.521
2503.384
2505.955
2513.716

Potentiometer readings
0.25426
0.32852
0.329180.33126

The magnetic rigidities and the potentiometer readings of four conversion lines of
411.795 keV transition are shown in Table 1. The relation between B,o and the potentiometer reading N in the current range 3 (3A to 32A) derived from the values in the table
is given byB,o = 3282.4 N+ 1260.8 G ·em,

where N is zero for SA and 1 for 32A. The constant term in the right-hand side of theequation corresponds to the B,o value for 8 A. This calibration relation is valid onlyin the range 3. In other current ranges calibration must be made by using pertinenttransitions.
The L-subshell ratios are obtained from the spectrum in Fig. 1 (6-1). The transition is known to be of pure electric quadruple (E2). The theoretical subshell ratios
are interpolated referring to the Sliv's table, and given by
LI : LII : LIII = 22 : 23 : 10.
The experimental values in the present work are
LI: Ln: Lui = 21.9: 23.6: 10,
which are in good agreement with pure E2 values.

Reference
1)

G. Murray, R. L. Graham and J. S. Geiger: Nucl. Phys., 63, 353 (1965).

25300

500

1000

1500

Fig. 1 (6-1)

y/30s

lK

Ln
~

L
!

8

/\..,.. .,.
_,.,

•

~

L. ,

1 mm
slit
2
source 0.3x20m m

5 Omm

411.795 keV

baffleAu

Momentum spectrum of the conversion electrons from 198Au.

Potentiom eter readings

C/.
/min

0.059°/o

19

(J1
t-.)

53

6-2. Nuclide Analysis using Nuclear Reactions

T. Hamada, M. Okano, A. Hashizume,
Y. Awaya, Y. Tendow,and T. Kato

The characteristics of radiations accompanying nuclear reaction and/or comingfrom the produced radioactive nuclei are specific for the reaction and the target nuclide
involved. A preliminary experiment on the nuclide analysis based on the above principle has been made.
The gamma -ray energies were measured mainly with a scintillation gamma -rayspectrometer having two types of the scintillation detectors: one is a 3 in ¢ x 3 in Nal(Tl), and the other a 1-3/4 in¢ x 2 in Nal (Tl) combined with a 6 in ¢ x 6 in Nal (Tl)annular crystal for the pair spectroscopy.
Several light nuclides of practical interest were bombarded in the small irradiation
room by 8 MeV protons through a No.5 beam duct, and the effect of background radiations were studied. The background contribution was found to be fairly reduced by thelead shield except for that of neutrons.

54

7. NUCLEAR INSTRUMENTATION AND TECHNIQUES

7-1. The 75 em Scattering Chamber

T. Fujisawa and Y. Awaya

The scattering chamber has been designed and constructed for universal use in theexperiments on nuclear scattering and reaction. A sectional view of the scatteringchamber is shown in Fig. 1 (7 -1). The chamber is 75 em in inner diameter and 54 em
in inner depth and its main parts are made of chromium plated steel. The whole scattering chamber can be rotated around the direction of the incident beam and moved horizontally and vertically. The side and top views of the scattering chamber are shown in
Figs. 2 and 3 (7 -1).
The side wall, the bottom plate and the top lid of the chamber have five, three andfour windows, respectively . The chamber contains a supporter of the target holder, aturn table and a turn arm. The axes of them are concentric within an accuracy of 0.1
mm. These three parts are connected to the lower lid through a bellows and are not
fixed to the lid, but are supported by the frame. Thus the essential parts of the scattering chamber are not influenced by the shrinkage of the vacuum chamber. The detectors and other equipments used in the experiments can be attached to the turn table,
turn arm and windows. By using the turn table and/or turn arm, the emitted particles
and radiations can be observed at any angle except at an extreme one, with respect tothe incident beam continuously . The turn table is supported by the side wall at its rim
and under a concentrated loat of 50 kg. The adjustments of the vertical position of thetarget, and of the angles of the turn table and the turn arm can be made without opening
the vacuum system. The angle of the turn table can be read with accuracy of 0.050 andthe angles of the target and the turn arm can be read with accuracy of 0. so. The chamber also contained a collimating system of the incident beam but it has been removednow.
The Faraday cup which is insulated from other parts is connected to the chamber
to measure the beam current. The resistance of the insulator is more than 2,000 M'SJ
at 500 OC.V. The aperture of the cup is 10 em in diameter and 30 em in length. The
distance between the target and the entrance of the Faraday cup is about 70 em. In
order to take away the effects of the recoiled electrons, a magnet (300 Gauss) is placedat the entrance of the cup.
On the top lid of the chamber, a target box is connected through a gate valve. The
target holder can be drawn into the box and the target is changed without destroying thevacuum. This box can be used as the evaporating system also when the targets aremounted on the holder without being exposed to the atmosphere.
The chamber is evacuated by a series of mechanical booster pump and rotary pump
to a vacuum of about 10-2 mmHg. Then the chamber is connected directly to the vacuurn system of the beam transporting system which maintains the vacuum under lo-4 mm
Hg.

55

Acknowledgments
We wish to thank Dr. Y. Hashimoto for his kind advice, Mr. T. Wada for his help inmaking accurate measurement, and Mr. S. Fujita for his trouble in drawing Fig. 1 (7-1).

(1) Target box (stainless steel), (2) Rod for introducing and taking out targets(stainless steel), (3) Gate valve (stainless steel), (4) Bolts for adjusting thecollimator, (5) Ball bearings, (6) Collimator of incident beam, (7) Target
holder which can hold four kinds of targets at the same time, (8) Holder of thesolid state detector, (9) Magnet which produces magnetic field of about 300
gauss and takes away the effects of recoiled electrons yielded at a target andthe Faraday cup in the measurement of the transmitted beam, (10) Faraday
cup, (11) Turn arm, (12) Base of the target holder, (13) Flange with vacuum
tight BNC connector, (14) Bellows, (15) Target stanchion which can be slided
up and down at about 10 em and rotated at 3600, (16) Shaft for turning the turn
table, (17) Turn table which can support the load of 50 kg rigidly and can berotated at 360°, ( 18) Vernier of turn table which can be read with an accuracyof 0.05°, (19) Acryl insulator, (20) Beam stopper (copper) which can be
opened to see the slit of the beam transporting system to adjust the alignmentof the chamber.
Fig. 1 (7 -1)

Sectional view of chamber.

56

3

2

1

(1) Hndale to drive the turn table,(2) Faraday cup, (3) magnet for
the Faraday cup, ( 4) Target box,
(5) Pre-amplifier of the solidstate detector, ( 6) Handle to drive
the turn arm, (7) Turn base torotate the chamber, (8) Handle toslide up and down the target stanchion, (9) Base plate to move thecenter of the chamber horizontallyand vertically, (10) Beam duct tothe cyclotron, (11) Duct to thepumping system.
Fig. 2 (7-1)

Side view of chamber.

57

4

2

7

(1) Permanent magnet to take away theeffect of recoiled electrons produced
at a target, (2) E and JE solid state
detectors, ( 3) Target holder on whichaNi target and a disk of quartz ·aremounted. The· beam spot on the quartz
can be seen with T.V. at the counting
room, ( 4) Aperture to the Faraday
cup, ( 5) Solid state detector for monitor,(6) Turn table, (7) Turn arm.
Fig. 3 (7-1)

Top view of chamber.

58

7-2. An Air-core Beta.-ray Spectrometer

Y. Tendow, A. Hashizume, andY. Awaya

Instrumental
A high precision, high resolution air-core beta-ray spectrometer with a mean
radius of 50 em has been constructed. There are two ways to create a double focusing
magnetic field with air-core coils: a pair of concentrically coupled solenoid coils oran array of several pairs of current loops. An "optimum field" which makes the aberrations zero to the higher order and the combination of three pairs · of current loops togenerate the "optimum field" have been computed up to a great accuracy!). Such anexact computation has led to construction of several spectrometers of the current loop
type in the world.
We adopted the current loop type spectrometer for the reason that it is possible tofit the magnetic field to "optimum" one to the higher order and to access easily to thesource and detector regions. The mean radius of 50 em is a com prom is~ between
contradictory requirements: a demand for a larger mean radius to gain a higher luminosity and that for a smaller radius to limit the cost and to attain easy handling.
The spectrometer is aimed at to work with line widths of some 0.05 %region in momentum rather than to attain an extremely high resolution. A resolution better than"-'0. 02% is rarely needed in practice because of the low counting rates.
The coil array consists of three pairs of current loops: large pair, medium pairand small pair. The current conductor is an aluminum strip of 32 mm in width and2.475 mm in thickness, which is wound on water-cooled aluminum bobbins with glass
fiber sheets as insulators and myler strips between each turns. The large coil andmedium coil have four sections and each section has 56 and 24 turns respectively.
The total turns are 448 and 192 respectively. The small coil has two sections of 25
turns each and 100 turns in total. The field expansion coefficients an with the actually
manufactured coil array fit to those of "optimum field" to the fourth order within acceptable tolerances.
The vacuum chamber is made of aluminum and has three baffles, one radiallyadjustable and two non-adjustable. The radially adjustable baffle is placed at the midway of the electron path and has an aperture edge profile of 0.04% resolution isoaberration contour. The chamber is evacuated to a pressure of Sx 10-6 mmHg with
an 8-inch diffusion pump located at 8.5 rneters from the center of the spectrometer.
A transister-controlled stabilized current power supply of 140 V, 100A at maximum is employed as an exciting current source. The exciting current is stabilized to
10-5 per an hour. Five current ranges can be selected by knife switches by shunting
the standard resistor stepwise. The current is increased by a precision automatic
stepping potentiometer with a minimum step of 7 .5x 10-6 of the maximum current in a
selected range. In an automatic scanning performance the starting value, the goalvalue and the stepping amount of the current can be selected arbitrarily by a matrix ofpush buttons.
A closed circuit cooling system with distilled water controls the coil temperature.

59

The distilled water coolant flows successively through a heater, a heat exchanger,
cooling channels in coil bobbins, a reservoir and an ion-exchanger column. The coolant
exchanges heat in the heat exchanger with city water chilled to a temperature of 10°C.
The temperature rises in the coils with a current of 85 A (3.5 MeV for electron energy)
do not exceed 2.5°C.
A side-window type G. M. tube with a,...___ 1 mg/cm2 mica window is used as a detector. The counting and printing are automatically controlied in connection with thecurrent scanning operation.
Because of the high resolution and the low magnetic field of the spectrometer, theearth's field (0.35 gauss for vertical component and 0.3 gauss for horizontal) and otherstray fields cannot be ignored especially for low energy electrons. The degaussing
coil system consists of a pair of current loops for vertical component: two pairs ofcurrent loops for south-north and a pair of rectangular coils for east-west. The vertical component is eliminated to less than 5 x 1o-4 gauss.
The spectrometer is installed in a specially designed non -ferrous building locatedat about 100 meters from the magnet of the IPCR 160 em cyclotron.
The spectrometer room is 6.3 meters by 6.3 meters in area and 3.2 meters above the floor and1.3 meters below the floor. A portion of the degaussing coil system is installed under
the floor. The cyclotron leakage field at the maximum excitation of 2x 1o4 gauss isabout 3 x 1o-3 gauss at the spectrometer site. The earth field nullification is performed
manually before the measurement of electron momenta with monitoring by a flux-gate
type fieldmeter. A system for automatic cancellation of external field is now being
planned.
Performances
As has been stated, the spectrometer is aimed at operating with a resolution of........,0.05% FWHM in momentum. The dimensions of actually manufactured coils, however, turned out well with tolerances of much smaller than previously permitted andtherefore the resolution of about,....... 0.02% became expectable in some favorable conditions.
The spectrometer performances were examined by using K, L and M conversion
lines of 661.59 keV transition in 137Ba. A drop of CsCl solution was deposited on an
Au evapolated myler film and heated to dryness with a flood lamp. The source thus
manufactured was 0.4 mm in width and 10 mm in height. Although the thickness andthe uniformity of the source were not so satisfactory, the ultimate resolution attained
was 0.025% FWHM with a baffle aperture of 10 mm and a slit width of 0.2 mm. The
transmission measurements and the current-moment um calibration are now being
undertaken using 137Cs, 198Au and 203Hg sources.

Reference
1)

G. E. Lee-Whiting and E. A. Taylor: Can. J. Phys., 35, 1 (1957), AECL No. 381(1958).

60

7-3. A Broad Range Magnetic Analyzer

N. Nakanishi, S. Motonaga,
M. Hemmi and K. Matsuda

A magnetic analyzer for nuclear reaction particles has been designed and is underconstruction. Various types of reaction particle analyzing magnets have been developed
to meet the need for high precession in nuclear physics. In general, a magnetic analyzer is required to attain brighter luminosity, higher resolution and broader energy
range. Certain types of a single magnet such as the Browne- Buechner type1), the Elbek
type2) and the Siegbahn type3) have been widely used.
The magnetic analyzer newly designed will be installed for the IPCR cyclotron andan array of multiple detectors will be employed as a detector system. The following
points are considered in designing the analyzer; (1) remarkable dispersion, (2) small
vertical magnification, (3) linearity of focusing line and (4) high luminosity and highresolution. More optical parameters are required to realize better conditions in
optical properties. So a combination of two homogeneous sectorial magnets with circular pole boundaries was considered.
In such a complex configuration of magnetic fields it is difficult to find an intuitiveor a simple analytical relation between the parameters and the ion optical properties.
So calculations were made by the trial and error method with a computer. The approximation of a sharp cut-off boundary is assumed throughout this work.
A magnetic field configuration obtained is shown in Fig. 1 (7 -3) and notations used
are summarized in the same figure. The optical properties of the magnetic analyzer
are as follows: The energy range covers from Emax to 0.67 Emax. The averageenergy resolution calculated is less than 1 x 10-3 when the solid angle is 2.5 x 10-3
steradian. The vertical magnification is about 2 and the dispersion factor about 6.
Both of the magnets have an air gap of 58 mm and their maximum B· fJ and magnetomotive force are 110 x 104 gauss· em and 7.5 x 104 ampere-turns, respectively.
One of them (PA-l) is 32 t and the other (PA-Il) is 30 tin total weight.
The analyzing magnet will be rotated over an angle from -15° to 1500 around thecenter of a 460 mm ~ scattering chamber.
Several shims, which approximate to a circular boundary by stepped one, aremounted at the entrance and exit with a curved boundary. Paramagnetic spacers of 5mm are installed to homogenize the magnetic field at the upper and lower sides between a pole piece and a yoke. The grade of parallelism of the pole face is achieved
at 0.01 mm and therefore it is expected that the grade of inhomogenity of the field isless than 5 x 10-3. Strech-wire method will be employed in examining ion opticalproperties of the magnet.

References
1)
2)
3)

C. P. Browne and W. W. Buechner: Rev. Sci. Instr., 27, 899 (1956).
J. Borggreen, B. Elbek and L. P. Nielsen: Nucl. Instr. and Meth., 24, 1 (1963).
N. Svartholm and K. Siegbahn: Ark. Mat. Astr. Fysik, 33, No.21 (1946).

61

Cite\

t,

1~ t.

1. ·. J~t t lM\+~: ~'.t'R,: z. ' r. I c.w.
R~ : lf-o 7. I r-.

t.

3 '· CJt.

•l 0.

R, : I , 'i o. t c..

f)

I J. oR,:t,- 7.o ..

w

I J}.f""f.

A

t

Fig. 1 (7 -3).

II •. oOb

I 1 r. o '-'•.

Upper drawing shows a designed magnetic field configuration in the medianplane of magnets and typical particle trajectories. In the lower side
calculated values are tabulated.

62

7-4. Data Processing System

T. Wada, Y. Chiba, K. Matsuda
and M. Yoshimizu*

As described in other section, the main features of our cyclotron are that theparticle energy is variable in a wide range and that many kinds of particles are available.
Using such particles, the nuclear data are abundant and complicated. To acquireand process the data, a large multi -channel analyzer is needed. But recently the cost
and the memory capacity of such analyzer do not differ substantially from those ofsmall general purpose computers. Because of the enormous data -processing capability and the flexibility of operation, many experimenters prefer the small on -line computers to multi- channel analyzers 1 '2).
We selected DDP-124 of Computer Control Company (now Computer Control
Division of Honeywell) of U.S. A. At that time ( 1965), the DDP-124 was the only small
computer made of IC with low cost, high speed and high reliability. The specificationsof this computer are as follows:Type
Binary, core memory, parallel, single address with indexing, and indirect
addressing.
Word length
24 bits, sign/magnitude code.
Speed
3.5 jlsec.
Adding14 Jl sec. (avg.)
Multiplying
Memory1. 75 Jl sec cycle time8192 words
Input/Output
24 bits parallel buffered or unbuffered channel.
Direct memory access channel, control pulse lines, sense input lines, andpriority · interrupt lines.
Software
FORTRAN 4 compiler with Boolean statements,
DAP 2 Symbolic Assembly Program,
Utility Routines.
Installation
60 cps.
3.5 kVA single phase 115 ± lOV
Power
1oo · to 400 C.
Operating temperature
0 to 90 %Humidity
The plug-in type units of Technical Measurement Corporation were selected as the
AID converter of input signals, because in the case of double parameter PHA, the coincidence analysis between analogue and digital data was also intended. The digital data
will be obtained from the detector array of the magnetic particle analyzer which is now

63

under construction .
When a computer is used as a PHA system, there are two problems, one of whichis that the dead time is very long. Using a priority interrupt line and coding the
program as rapid as possible, the dead time can be reduced to about 30tt sec. Because
the clock pulse of AID converter is 4 Me, the total dead time per one input signal is
0.25N + 30 tt sec, where N is the ·channel number into which the input signal is to besorted.
To reduce the dead time loss, the best method is to close the current integrator
during the dead time of the PHA system. We are now designing this circuit.
Another problem is that the treatment of the computer is not so easy as a wjred
program PHA system.· Hence, we have designed a PHA Control Unit, which is composed of many switches. By setting these switches same as in the case of a wired
program system, the experimente r can specify any functions of PHA, for example thetype of CRT display or the memory region into which the data is stored.
The computer program reads the status of each switch and accomplishe s the corresponding function. Some of the switches are not read but used to interrupt the computer program or to set the sense lines. Our system has 8 level priority interrupt
lines, 8 sense lines and 16 control pulse lines. The priority interrupt lines are as
follows:
# 7
spare
# 6
Accumulate Stop
# 5
Accumulate Start# 4
A/D Conversion Complete# 3
DMA Channel End of Range# 2
Data Output Start# 1
Data Output Stop
# 0
spare
The power failure interrupt has the highest priority over all of these lines.
configuration of whole system is shown in Fig. 1 (7 -4).

The

* Kyokuto Boeki Co., Ltd.

References
1)
2)"On line Computers in Nuclear Research"; Nucleonics Vol. 22, No. 12, (1964).
"Automatic Acquisition and Reduction of Nuclear Data", Proceedings of a Conference organized by EANDC at Karlsruhe, (1964).

H

LiB•

(1.6)

J

ru ._

S..• LiD• (8)Priorit,.
IDtvnpt

htte:rParallel I/0

M..Ol7I/O

t-

DDP-124 PHA system configurat ion

TypewriterProtected

Fig. 1 (7 -4).

PunM.

InterfaceBM.503Tektronix

~

Diap~

Power Failure

PlotteryCentralDDP-124

Di«italI

Access Channel

Direct M.or.r

Magnetic Tapet"!h ........,

Il

Pill Cetrol Unit
: (II)(I)

Parallel Input

: _00

I

ft£ 222

Processor

Paper Tape
Reader/l

Til: 244

t---

(A.)

Option lntertace------- --,
Unit

81

-.

242

r- -- r

~

i
II:
2l

B)

Line Printer~65

7-5. A Charge Spectrometer

N. Saito and M. Aratani

As one of the nuclear instruments related with the IPCR cyclotron a charge spectrometer is now under construction. It is a specially designed mass spectrometer forstudying multicharged ions produced by nuclear transformations. The charge spectrometer is the first machine of this type constructed in our country. It consists of thesource chamber, the differential pumping system, the analyzer and the detection system.
The source volume is one of the technical features of the charge spectrometer. It
is a cone-shaped chamber of approximately 30 f. Twenty-stage ring electrodes ofgradually decreasing radii are installed inside the chamber in order to focus the ion
beam produced in the cone without any volume effect.
The ions entering the analyzer tube through an entrance slit are deflected by meansof a 90° sector magnet of 20 em deflection radius.
The detection system is required to be of high sensitivity due to the extremely low
intensity of the multicharged ion beam. Therefore, the pulse counting method using
electron -multiplier is adopted.
An X -ray ionization source chamber is provided for the study of the multicharged
ions artificially produced by X-ray irradiation of non-radioactive samples.

66

8. RADIOCHEMISTRY

8-1. Charged-p article Activation Analysis

T. Nozaki

Semiconduct or silicons of various origins were analyzed for carbon by the 12c(3He, a ) 11c reaction. Although beryllium and boron also give 1lc by the 3He-bombardment, it was sure, from their preparation procedures and electrical properties,
that the samples contained less than 10 ppb of them.
The sample disks (3 em diameter, 0.5 mm thickness) were bombarded by a deflected 3He-beam (22 or 14 MeV, 0.5-. 1ttA) for about 20 min, with the beam current
being integrated and read by an integrator. After 10 min, during which 30p formed
mainly by the 28Si (3He, p) 30p reaction almost decayed away, the sample surface(10-. 15 p.) was etched off to remove the possible surface contqminatio ns. A simple
equipment was devised for undertaking the HF- HN03 decompositio n of the sample within a closed system; two bottles of flexible polyethylene were connected by a siliconerubber tube, one of them being used as the decompositio n vessel and the other as thecontainer of a solution of NaOH and carrier Na2C03. Air in the both bottles was
squeezed out just beofre the decompositio n, which was started by adding HN03 to thedecompositio n vessel containing the sample and HF. Gas evolving during the decomposition was caught by the NaOH, and, when the decompositio n was completed, thecontents of the both bottles were mixed to give an alkaline mixture. Then, C02 containing 11c was liberated from the mixture by adding HCl and converted into BaC03.
The annihilation radiation from it was measured by a scintillation counter with a single
channel analyzer, and the decay was followed. The carrier recovery was determinedby the acid-alkali titration and found to be usually about 60%. A graphite disk was
bombarded similarly but with a much lower beam flux and used as the activation
standard.
When the 3He energy was 14 MeV and the surface contaminatio ns were carefully
removed, the measured 11c activities corresponde d to carbon contents of less than 300
ppb, varying according to the origins of the samples. For this 3He energy and 1 p.A
flux, the detection limit was several tens ppb of carbon. When the 3He energy was 22
MeV, the 11c activities were much higher, correspondin g to apparent carbon contentsof 7-- 11 ppm for all of the seven different samples; this was due either to an unexpected occurrence of the 28Si (3He, 2~e) 1lc or 16o (3He, 2 a) 11c reaction or to an
incomplete removal of the surface contaminatio ns. (With the 28Si (3He, 2DNe) 11c
reaction, the threshold is 11.3 MeV, and the penetrabiliti es of the 11C through the
Coulomb barrier are of the order of 10-2 and 10-20 for the 3He energies of 22 MeV and
14 MeV respectively .) Further efforts are now being made to establish more reliableconditions for the analytical practice and to analyze more of the samples.

67

8-2. Recoil Chemistry

N. Saito, F. Ambe and S. Ambe

The behavior of recoil atoms is determined by the following three factors: the typeof the nuclear reaction inducing the recoil, the nature of the recoil atom itself and thephysical and chemical properties of the media in which the recoil takes place. Therefore, one of the most fundamental methods of approach to recoil chemistry is to study
in a systematic way the effect of the three factors on the chemical fate of the recoil
atoms. From this point of view, we have been studying the recoil reaction of halogen
atoms following neutron-induced nuclear reactions in halates and related compounds 1,2).
In the present investigation, iodic acid and several iodates were irradiated with slow
and fast neutrons, and the oxidation state of the recoil iodine atoms arising from the127r(n, r)128r and 127r(n, 2n)126r reactions was studied.
Fast neutrons were produced by bombarding a thick beryllium target by 16 MeV
deuterons accelerated in the 160 em cyclotron. The maximum energy of the neutronsobtained is estimated to have amounted to 19.5 MeV. The beam current of the deuterons was 0.5- 1.5 ttA. The flux of neutrons with energy higher than the threshold of
the 127I(n, 2n)126r reaction was 107-.. 108 neutrons/ em 2. sec at the site of irradiation.
Slow neutrons were obtained by moderating the fast neutrons through a paraffin block
10 em thick. The flux was 10°"'"' 107 neutrons/cm2 sec. The cadmium ratio for
iodine was 2.1 in this condition of irradiation, which indicates a fairly large contribution of resonance neutrons in the 127r(n, r )128r reaction.
Iodic acid and iodates listed in Tables 1 and 2 (8-2) were irradiated for 1 hr. at
dry ice temperature by slow or fast neutrons to induce the (n, I) or (n, 2n) reaction,
respectively. The irradiated iodic acid was dissolved in an aqueous solution containing
a large excess of sodium hydroxide and the solution was neutralized carefully withdilute nitric acid. Iodates were dissolved in water. Potassium iodide or sodium
periodate was added as carriers. Radioactive cations were eliminated by an ion exchange resin. Iodine atoms in lower oxidation states were separated by the precipitation of silver iodide or by the exchange extraction of molecular iodine. Periodate
ions were separated as potassium periodate precipitate. The radioactivity of 128I
and 126r was measured by means of a sodium iodide scintillation counter. In case of1261, the distribution of activity was determined from the photo peak area of 390 and
670 r -rays to eliminate the contribution of 124sb and 127mTe - 127Te produced by
fast neutrons.
The results are given in Tables 1 and 2 (8-2). The "retention" means the percentage of recoil atoms found in the chemical form identical with the starting material,in this case, the iodate ions. In all the compounds studied, almost no activity was
found in the periodate fraction.
It is seen from Table 1 (8-2) that the retention of the hydrates is lower than thevalue for the corresponding anhydrous salts. A similar effect was reported by Saito
and Tomita for arsenates3). In the anhydrous salts, cesium iodate shows an exceptionally high retention. This anomaly is thought to come from a difference in the
crystal structure or the close resemblance of the mass of iodine and cesium atoms.
Comparison of the data in Tables 1 and 2 (8-2) indicates that for both iodic acid andiodates the retention of the iodine recoil atoms is fairly different for the (n, r) and68(n, 2n) reactions. This is in agreement with the report of A ten and his coworkers forpotassium iodate4) and presents a striking contrast to our result on bromate1). For
sodium bromate almost no difference was observed between the retention for the79Br(n, r )80sr and 79Br(n, 2n)78sr reactions. A possible internal conversion processaccompanying one of the nuclear reactions may have caused such difference in iodic
acid and iodates.
Further work is in progress on other compounds and other nuclear reactions.

Table l (8-2).

The Retention of 1281 Following theReaction in Iodic Acid and Iodates

127 I(n, r ) 12 81

Compounds

RetentionHI03

50± l%

Lii03

58± l

Nai03

57± 1

Nai03 · H20

38 ± 1

KI03

57± 1

Csi03

65 ± 2Mg(I03)2

60 ± 3Mg(I03)2 · 4H20

42 ± 2

Table 2 (8-2).

1
The Retention of 1261 Following the 127I(n,2n) 261
Reaction in lodic Acid and Iodates

Compounds

Retention

HI03

42 ± l%Nal03

37 ± 2

Nai03 · H20

30 ± lKI03

39 ± 1

69
References
1)
2)
3)
4)

N. Saito, F. Am be and H. Sano: Nature, 205, 688 ( 1965 ).
N. Saito, F. Ambe and H. Sano: Nature, 206, 505 (1965): N. Saito, F. Ambe and
H. Sano: Radiochim. Acta, in press.
N. Sait-o and I. Tomita: Bull. Chern. Soc. Japan, 35, 1127 (1962).
A. H. W. Aten, Jr., M. Lindner-Groen and L. Lindner: "Chemical Effects of Nuclear Transformations", Vol. 2, p. 125, IAEA, Vienna, 1965.

70

9. RADIATION CHEMISTRY AND RADIATION BIOLOGY

9-1 LET Effects 1n the Radiation Chemistry and Radiation Biology

M. Matsui, T. Karasawa, M. Imamura, H. Seki,
K. Nakano, A. Matsuyama, and S. Kitayama

The chemical effects of radiation generally depend upon the nature of the radiationand its energy. It is called LET effect. A convenient parameter to use in characterizing various kinds of radiations is the amount of energy lost per unit distance along
the track of the charged particles which constitute the radiation. This energy loss
parameter, perhaps best represented by the symbol -dE/dX, has often been called"linear energy transfer" or LET. For the stopping of the charged particles, it isgiven by the Bethe formula -dE /dX =4nz2e4NZ /mv2ln (2mv2 /I). Then LET is proportional to the electron density NZ of the sample and the square of the charge ze ofparticles, and increases with decreasing velocity v of particles. I is the mean ex.citation potential, which is I !:= 66 eV for water.
In the radiolysis of liquids, it is assumed that the primary products such as ions,
free radicals and excited molecules are localized in the so-called "spur". The
radiolysis of an aqueous solution was well explained by assuming the diffusion of the
spur. Consequently , two types of products, i.e., "molecular" and "radical" products
are considered. The former is produced by the interaction of the primary productsin the spur region, and the latter is formed after homogeneou s distribution of the
primary products is completed. The difference in the reactions caused by the various
kinds of radiations is thought to be attributed to the difference in the above-descr ibed
spacial distribution of the primary products.
The irradiation of the high LET radiation is very important in view of the fundamental studies of effective utilization of atomic energy and of its effects on the Uving
body. The studies on the LET effects carried out in our laboratories using the recoil
particles have shown many interesting features. These are: (1} the increase inG(CH 20} and the decrease in G(CHzOH}z with increasing LET in the radiolysis ofliquid methanol, (2) the variation of the yield of solvated electrons with LET in liquidmethanol, ( 3) that of the yield of "molecular" hydrogen from methanol and tetrahydrofuran, (4) that of G(HzOz} from the neutral aqueous solutions containing Cl-, and (5)the relation between LET and killing or mutational effect on microorgani sms. Further
studies necessiate the use of the cyclotron radiation with intermediate LET to obtain asystematic information. We have, therefore, attempted to establish a method of determination of the dose rate of these radiations using ordinary Fricke solutions in comparison with a suitable physical method.
The solutions contained 10 mM of ferrous ammonium sulfate, 1 mM of NaCl and 0.4
M of HzS04. The concentratio n of ferric ion was determined directly from the opticalabsorption at 305 m.u; the molar extinction coefficient was taken as 2174 at 23. 7°C.

71

Generally, in the experiments with an accelerator, it is important technically tohave a suitable beam onto the target. Irradiation was performed through a thin glass
window set on the irradiation cell, after passing a thin aluminum window and an air
layer. Since the beam profile was about 3-- Smm, the intensity was relatively small,(1-·10) x 1o-9A, but the density became 0.2tt A/cm2.
Irradiation was made at the end of an evacuated pipe through which the deflectedbeam from the IPCR 160 em cyclotron passed. Solution was magnetically stirred in
the cell. The input charge in the solution was monitored by reading the current bymeans of a platinum wire dipped into the solution and connected to ground through acurrent integrator. Since no correction for the production of secondary electrons has
been made in the current measurement, the result shown in Fig. 1 (9-1) is essentiallyrelative in nature. However, this relation between the physical and the chemicalmeasurements may be used practically with an accuracy of .±10%. The determinationof G(Fe3+) in the radiolysis with a variety of heavy ions and 3He++ (15- 45 MeV), and theexamination of LET effects in the radiolysis of methanol, furan and biological systems
will be our main projects in the future.

o.a
0.7
0.6
0
'd
rt

.....
0

0.5

In

1-'

t:l

Cb

::srn
.....
rt
«

0.4

0.3
0.2

0.1
10

20

30

40

50

60

10- 8 Coulomb

Fig. 1 (9-1)

Relation between optical density (Fe3~ and total charge input.

72

10. SOLID STATE PHYSICS

10-1. Radiation Damage in Sol ids

R. R. Hasiguti, M. Sugimoto, H. Sakairi,
N. Shiotani, and T. Okada

The behavior of lattice defects created by particle irradiation and their effects onmaterial properties are the main subjects of this research.
For the present we can make experiments only at room temperature, but a cryostat
for irradiation at liquid nitrogen temperature is now being prepared.
The problems to be studied in this 'year are as follows:(1)

Annealing process of vacancies in metals.

Quenching, a usual technique to introduce vacancies into crystals, is notadequate for the study of the annealing process of single vacancies, because someparts of quenched-in vacancies cluster during quenching. We study, therefore, theannealing process of single vacancies introduced into crystals by particle irradiation
by measuring the electrical resistivity. We are also interested in interaction ofvacancies with other lattice defects such as dislocations.
(2)

A mechanism of swelling of irradiated metals.

Some materials irradiated by neutrons show swelling due to the formationof gas bubbles such as of helium or xenon, as products of nuclear reaction. In neutron
irradiation experiments, however' detailed experimental analyses of materials are
obstructed by residual radioactivity. We are going to observe the formation processof bubbles by the transmission electron microscopy, by making simulative experiments with a -particle irradiation. We consider that lattice defects such as dislocation
may play an important role in the process.
(3)

Damage in ferrite.

There are only a few experiments about the irradiation effects on themagnetic properties of solids. We start the study of changes of magnetic susceptibility and coercive force of ferrimagnetic ferrites by particle irradiation.

73

11. Rl PRODUCTION AND ITS APPLICA TIOINS!

11-1. The Irradiation System

A. Hashizume and A. Shimamura

The ever-increasing interest in cyclotron produced radio-isotopes has necessitatedan irradiation system. To minimize the irradiation hazards in RI handling, it isdesirable to treat this system by remote control.
These radio-isotopes lie in general on the neutron deficient side of the nuclear
stability line, in contrast to the nuclei formed by neutron capture or as fission products. They are usually of chemical elements different from those of the targets.
So we can obtain by suitable chemical techniques the high specific activity which canaccede to the demands in various parts.
For handling automatically the RI target system, a problem arises regarding theremoval of intensely radioactive targets from the vacuum chamber of the cyclotron.
We have constructed a target system in which the target can be withdrawn from thevacuum chamber and demounted from the cooling system by remote control. The
target-mounting assembly is attached to a cylinder which has hydraulic pipes. Thiscylinder brings the target by a screw mechanism to a proper position of the beam in
the cyclotron and withdraws it at the end point of bombardment. The target can beremoved by another screw mechanism. This withdrawing or removing operation of
the target can be done at the control room of the cyclotron. Thus there occurs noirradiation hazard.
Before attaching the system to the cyclotron, the cooling efficiency has been tested
by setting a 1 kW heater on the target position. No appreciable rise of temperature
was observed in the aluminum plate which was cooled with water. A bombardment ofalpha-particles of 30 MeV with 15 11-A has been safely carried out. We are going totest the maximum thermal capability of the target by using ion beams. Fig. 1 (11-1)
illustrates the target system.
The construction of a transport system of the irradiated targets by remote control
to the next room where the chemical handling can be done is in project.

wd&A-\-t c.. of;,.}m\~~.t sw-1-- - - -

I

I

I 1

Fig. 1 ( 11 -1)

I

1

~\

811111~-10om.

~"""oc.t"'t ;""'~

SY/ ~r tM&eJ:.

i©~----- -· ------- - - - - -Irradiati on system for RI production.

dis~ Ia.ce.oM\eA't

IW\C)to" -fo"' to..-, at--------------~?NJ"lor for tOA~t M\DU'Y\ti~3 a'"'tl cLe'"'o"~tiM}

~

""-J

75

11-2. Safe Handling of Irradiated Targets

T. Hamada and T. Nozaki

A hot cell of 3.90 m wide x 1.05 m long x 1.85 m high, consisting of threecompartments, has been designed and its construction is under way.
The irradiated target is carried remotely from the cyclotron room into one of the compartments by a transfer system, removed from the holder with ball- joint manipulatorsand processed in the neighboring two compartments. Gamma activity of up to 50 inC
of Na-24 equivalent will be handled safely in the cell.

76

11-3. Preparation and Isolation of Carrier-free 76As from 78se

M. Inarida

The present paper deals with the radiochemical isolation of c~rrier-free 76As
produced by bombarding 78se with 14 MeV deuteron-particles.
The target composed of enriched 78se metal powder wrapped in a 10 tt thick nickel
foil was bombarded for 15 min at a beam intensity of 0.5 IJ,A with 14 MeV deuterons by
the 160-cm cyclotron. After bombardment, 20 mg of the target were dissoLved in 5
ml concentrated HN03. · The separation method of carrier-free 76As from 78se isschematically shown as follows:
Target (enriched 78se)~Cone. HN03 5 ml
dry up~ Cone. HN03 2 ml
dry up0.1M HCl 20 ml
20 %Na (DDCT) 2 ml
TBP
5 ml
.
(2 times)
Extraction

F
I

I
Aqu.

Br- one drop ~HN03 2 ml
CCl4
5 ml

I
Or g.
Se (IV)

Extraction ( 3 times)

I

I

I

Aqu.

Or g.

76As(V)

82Br** Radiobromine produced by thereaction of deuterons with 82sein the target.

The activity in the carrier-free arsenic fraction was identified by the 26.5-hourhalf-life and by the 0.559 and 1.22 MeV gamma-rays reported for 76As.

77

11-4. Preparation of 18f-labelled Compounds

T. Nozaki
Anhydrous Hl8F was prepared very efficiently by the 3He- or a -bombardment ofan oxygen gas stream to produce 18F and the occasional elution of the 18F with gaseous
HF. The 18F formed in the stream is adsorbed almost quantitatively on the inner surface of the bombardment vessel and eluted easily by gaseous HF mixed with the oxygenstream to give Hl8F. Hence, the bombardment can be continued throughout the elution.
Fig. 1 (11-4) gives the yields of 18F calculateq from the reported excitation functions,and Figs. 2 and 3 (11"'"4) show the block diagram of the equipment and an elution curveof 18F respectively. A more detailed ·r eport will be published in the Int. J. Appl.
Radiat. Isotopes.
The bombardment of a streaming gas target, in general, has the following advantages; (1) a gas target has a much larger surface area for cooling than a solid target,(2) the stream itself continuously carries away the evolved heat and radiation-produced
substances (e.g. 03), and (3) any gaseous substance (e.g. anhydrous HF) can be transported through the bombardment vessel with the stream. Thus, the bombardment
technique is also useful for preparing many kinds of 18F -labelled compounds including
fluorosteroids-18F and benzotrifluoride-18F.
Studies are now being undertaken to prepare cholesteryl fluoride-18F; a sus pension of AgF in acetonitrile is added to a silver bombardment vessel adsorbing 18F and,after shaking the vessel for 20 min, cholesteryl iodide dissolved in xylene is added to
the vessel and made to react with the Ag18F to give the desired product. Crude cholesteryl fluoride-18F can thus be obtained with a satisfactory yield, but its purification
involves some difficulty which should be overcome in future. Benzotrifluoride-18F has
been obtained quite satisfactorily by the following procedure: (1) the inside of a polyethylene bombardment vessel is coated with SbF3 by evaporating up its ethanolic
solution, (2) the oxygen stream is 3He-bombarded in the vessel, and (3) the SbF3
labelled spontaneously with 18F is collected mechanically and made to react withbenzotrichloride to give benzotrifluoride-18F.

78. 1.5Xl0 9

1 X)0 95 Xl0 8

0

150

100

50
Range (mg/ cm 2 )

0

a

20

40

30
I

I

I

He

3

0

Fig. 1 (11-4).

10

2JEnergy (MeV)30

Thick-target saturation activities for the
18p and the 16o + 3He - 18 F
16o + a reactions in 02.

79

H

~: /~
_c , ___c-, ~ -

\

\

I ·.

·~ \

~ I

I

,

;

\

~

'

'

\~\
- "I

F

~

G
I

A

J

D

A: Oxygen cylinder, B: Flow-rate controller and flow-rate meter, C: Cock,
D: HF reservoir, E: Bath, F: Charged-particle beam, G: Bombardment
vessel, H: Cooling-water tube, I: Cold trap, J: Waste-gas reservoir.
Fig. 2 (11-4).

Equipment for preparing anhydrous H18F by charged particle
bombardment of an oxygen stream.

80

100

,--.....

~.....__.....
"""d
0

"'~_)

......<:.)
00rl~......-

50

~
~

0

~

0

0.5

1.0

Total · HF - passe d (g)Vessel size: 2 x 7 x 20 em
Flow rate : 02, about 150 ml/min ; HF, about 0.1 g/min.
Fig. 3 (11-4).

Elution curve of H18F from a silver bombar dment vessel.

1.5

81

12. RADIATION MONIT ORING

12-1. Radiatio n Monito ring Station

T. Hamada, M. Okano and M. Ota

A radiation monitori ng station has been built at about 85 m apart from the cyclotro n
and operated since Oct. 1966.
Two scintilla tion detector s and a BF3 counter are used to measure the radiationlevel at that position. One of the scintilla tion detector s is a 1--1/2 in ¢ x lr--1/2 inNal(Tl) which has a compens ation shield specially designed for the gamma- ray dose
measure ment. The other is a 3 in ~ x 3 in Nal (Tl) which is used for spectros copic
analysis of gamma- rays. The analysis is consider ed to be essentia l to distingu ish theradiation s leaking from the cyclotro n room and other artificia l sources from those of
the natural backgrou nd.
The BF3 counter has effective dimensio ns of 50 mm ¢ x 236 mm and is filled withenriched BF3 gas at 600 mm Hg, covered with 1 mm Cd and 10 em paraffin , and madesensitive only to fast neutrons .
The pulses from the small scintilla tion detector and the BF3 counter are fed to thescaler and the counts, scaled down to 1/100 and 1/10 respecti vely, and printed at 15
min intervals .
A record of monitori ng during the period from Nov. 1966 to June 1967 is shown in
the figure, where the radiation level is given in the unit of p.R/h which includes thecontribu tion of soil radioact ivity (2.5 .uR/h) as well as the apparent dose rate equivalent to 0.6 ,u.R/h due to cosmic rays and the detector contamin ation.
The leakage radiation s from the cyclotro n were not detected during this period,
while the radioact ive fallout due to the nuclear explosio n test in Red China on Dec. 28,
1966, was sharply detected as indicated in the figure.

of nuclear explosion test in Red China on Dec, 28.

50
I--

30

~

~

'"M
~

~

-

II

10
~

I)

~

f-

s:::

o

5

+-l
tU
of"4

~

M

3

•

1'1

~

-

of"4

.

l

~

::l.

t'l

J

11 III ,I., III IIII

1'1 1111",)'II ~IIII"' I'" "I ',II tl',III 1111 I)
It

II

II 11 1 1. 1

.It ,J 11,1 tl

1111

II

•tU

a

-

tU

t-'

1

L..-.

Dec.

Nov.
1966

Jan.

Feb.

March

April

1967

Each bar represents the range of variation of the dose rate during 24 hrs.
observed from time to time are due to radon daughters falling down with r
sudden increase on Dec. 30, 1966, and the following decay indicate the effe
explosion test in Red China on Dec~ 28.
Fig. 1 (12-1).

Record of radiation monitoring at the station 85 m apart fr

83

12-2. Health Physics

K. Koda and I. Sakamoto( 1)

Radiation Shielding

The shield walls provided for the IPCR cyclotron and the associated equipments
are made of ordinary concrete 1.0 -2.3 m thick and able to keep the outside radiationlevels (gamma-rays plus neutron) below the values permissible to non-occupational
people even when a thick Be target is bombarded by 200 11-A beam of 25 MeV deuterons.
The entrances to the cyclotron room and the experimental areas are equipped withshielding water tanks. The cyclotron rooms and the experimental areas are accessible from the control room through an underground passage.
In the early stage of test working, rather high radiation levels as much as 103 104 cpm of fast neutrons and 10 mR/h of gamma rays were observed at a point of theunderground passage, that is in the vicinity of the loopholes and the shielding doors.
Shielding was somewhat increased afterwards and the latest data show satisfactory
results as given in Fig. 1 (12-2). The results imply that in this case the mainradiation source is the cyclotron and not the target.
(2)

Residual Activity

A dose map of the controlled area measured 3 hrs after machine shutdown isshown in Figs. 2 and 3 ( 12- 2). In Fig. 2 (12- 2), it is shown that the cyclotron itself,
the slits and the beam stopper are the main radiation sources. The surface dose rateof the beam stopper was 100 mR/h. just after machine shutdown, falling to 80 mR/hafter 6 min. The nature of the induced radio-nuclide is not yet identified. Fig. 3(12-2) shows the residual dose rate distribution around the cyclotron. Higher dose
rate near the stairs are due to the solid wastes stored there.
(3)

Contamination"Dusting-off" of loose surface contamination (2 x lo-6 J..L C I cm 2 beta+ gamma)has been observed only on the floor near the cyclotron.
(4)

Personnel Monitoring

The gamma film badge was issued to all staffs and some of them had a pocket
dosimeter which indicated the sum of fast neutron and gamma dose. Table 1 (12-2)
shows the accumulated dose distribution of the staffs during 6 months.

84

Table 1 (12-2).

Accumulated dose distribution of the staffs
from Oct. '66 to Mar. '67

Rank of Accumulated dose

A

B

c

D

E

No. of staffs

2

10

3

6

1

Average dose per person: 85 mrem
Maximum dose: 370 mrem
Rank A: undetectable, B: 10-- 180 (mrem), C: 61 -- 220 (mrem),
D: 101 --420 (mrem), E: more than 300 (inrem).

_j

I

,,,

DOOR

SLIDING!

I I I tI

Fig. 1 (12-2)

-

i

I

0.02

0

.O.Ol
upx.
I

EXPERIMENTAL
AREA( S)

X- ,

I

I

I

I

CYCLOTRON ROOM

SCALE

I
I
o12345m~uP::::::.

Q..

I

CYCLOTRON
RopM

NEUTRON = CPM(UNDERLINE) •GAMMA= mR/t,

DOSE UNIT.

UNDERGROUND PASSAGE

70 ,-----, ~

0.16

Q_

0.0~

Q..

ARErL)

EXPERIMEMTALCONTROL ROOM +-UPx _Q_

CYCLOTRON
ROOM·. , / ) ~·,' /SLI,DI,NG .,. ·.
~ , , DOOR

BEAM COURSE ~ 5
TARGET : SILICA

Eo(. = 29MeV~TING C(}.JDITIONS.

Machine leakage radiation (neutron and gamma).

CONTROL ROOM

0.02 )(_Q_

III~N,~~ l l

EXPERIMENTAL AREA ( L)

EXPERIMENTAL
AREACS)THIS INCLUDES 0.02-wtfYh BACKGROUND RADIATION. )( MEASURED ON
MAY 8 '6'7.

C/1

(X)

86

(MEASURED 3hrs. AFTER HA(}I "NE SHUTDOWN.)GAMMA , rnR /n.
E 3He 35HeV, OPERATED 15hrs.
------'-----,

t-- 0.0 2 -Fig. 2 (12-2)

Residual activity pattern (I).

(MEASURED JUST AFTER MACHINE SHUTDOWN)
GAMMA

mR/h

cd. 29MeV, OPERATED 3hrs.
EXPERIHETALAREAC S)

EXPER l MEN TAL AREA< L)ll
J_ _ _ _ _......_.__ _ _ _ _ _ _ _ _ _ 5 - - - - - - - - - -- -- - - - -Fig. 3 (12-2)

Residual activity pattern (II).

87

13. LIST OF PERSONNEL

the IPCR Cyclotron Construction Committee
if~

~

J{

=f

~

~u

m D
~

~

l5i:
iE

fJ r:p
Jf . Jfi

-Fa

~

Jfi

~

1l
1f
llli

~

M

w ~

=:k.
=
-±
p

±
~lj

m

fit
~

=:k.

753t

~
~

Hi roo KUMAGAI (chair m an)
Toshizo TITANI
Ryukiti R. · HASIGUTI
Seishi KIKUCHI
Itaru NONAKA
Nobufusa SAITO
Shoji SETO
Kenic9i SHINOHARA
Yoshio SUGE
Yoshio TSUGE
Fumio YAMASAKI

the IPCR Cyclotron Adminstration Committee
LIJ

~

m

(:]

if~

1:t

A
I

t-t

~

~

~

83

~

LIJ
Jfi

Jf
~

83

*r:p

3t
l5i:
J{

~
-±
p

=:k.
E3

E3

1fA
~

15
1t

m
~

m

Fumio YAMASAKI (chairman)
Ryukiti R. HASIGUT I
Hiroo KUMAGAI
Masashi IMAMURA
Takashi KARASAWA
Kazuhisa MA TSUDA
Akira MA TS UY AMA
Nobufusa SAITO
Mitsuo SUGIMOTO
Yutaka G. TANAKAManagers of Users Group
Tatsuji HAMADA
Masatoshi ODERA

88

the IPCR Cyclotron Constructing Personnel
Leader
~~

~

Jl

7<::.

Magnet7f: 7k BB -t& Jt ~ Ji:\:~ w ~ _g:

Hiroo KUMAGAI
Shoshichi MOTONAGA,
Masatake HEMMI,
Noriyoshi NAKANISHI

f.j

~

'B

~

~

-T

~
~

PJ 1¥1

=!¥

'B

~

~

±

1=1

EB _g: fF

Isao KOHNO,
Tadao TONUMA

~

~

~

-

Isao KOHNO,
Shigeru TAKEDA

#

J:

~

~

Toshihiko INOUE

Hiromichi KAMITSUBO,
Kazuhisa MATSUDA,
Noriyoshi NAKANISHI& Jt
7f: 7k

~

Ji:\:

BB -t

Masatake HEMMI
Shoshichi MOTONAGA

Tatsuji HAMADA,
Tadashi NOZAKI,

fri
~

J1\
:f1

~

Akira HASHIZUME
Akira SHIMAMURA

~

EB

!A

Kazuhisa MATSUDA

,j-,

=!¥

1~

Masatoshi ODERA
Isao KOHNO-1f~

Takashi KARASAWA
Yoshitoshi MIYAZAWA

Oscillator
tj'\•=!¥ lE
~

~

1~
;1!;

Masatoshi ODERA,
Takashi FUJISAWA,

Vacuum Systemf.j ~-1fTakas hi KARASAWA,
F i'B lE 1$
Tadao TONUMA~~

Yoshiaki C HIBA
Osamu TERASHIMA
Yoshitoshi MIYAZAWA
Kisaku YOSHIDA

Ion Source

w 1ff

F

~

i'B lE 1$

Shunji NAKAJIMA

Control

w 1ff

~

¥r EB

~

Beam Transport
J: !-'¥ ~ j]!
~ EB !A~"5~

RI System
~

EB

1ff

~

ji

%
-

iE

General Management
Tatsuji HAMADA,~ EB j i -M

the IPCR Cyclotron Operating Personnel
Management
~

~
-1f7k
BB
7f:
-t

~

~

~

~

f6]

iff
1$

~

-rn

j]!

~

Takashi KARASAWA,
Shoshichi MOTONAGA,
Yoshitoshi MIYAZA WA

lE

w 1ff

~

7ln J::fL=~

Operator
Ji EB~* EB % 1'F±

1=1

Shin FUJITA,
Hisao NAKAJIMA,
Noburnichi OSA WA,
Kisaku YOSHIDA

~

~

ffl

=tf

~

~

Kumio IKEGAMI
Kiyoshi OGIWARA
Osamu TERASHIMA

89

Scientific and Engineering Personnel
Cyclotron Lab.
~

1:t 1[ :X.
tR ~ ~

~

~

11~

a w::

J: j;f 1i: Ji

Jt~'8 tR f!

~

jiij'

I=P

I;

~

-

lj'

~

iE

~

1'r

~

~

EE

~

•

Hiroo KUMAGAI,
Takashi FUJISA WA,
Masatake HEMMI,
Hiromichi KAMITSUBO.
Isao KOHNO,
Yoshitoshi MIYAZAWA,
Shunji NAKAJIMA,
Masatoshi ODERA,
Shigeru TAKEDA,
Takeshi WADA

=f

~

~

EE - H3
J: ~ ~

#

tff

~

1i!t

~

~

~

EE

~

7C

7k

I=P
I;

w ~ ~

F

iB iE it

~

~

w -T-

fi Jl\

M
it

-t

a§

t.t

-

~

Yoshiaki CHIBA
Jiro FUJITA
Toshihiko INOUE
Takas hi KARAS A WA
Kazuhisa MATSUDA
Shoshichi MOTONAGA
Noriyoshi NAKANISHI
Akira SHIMAMURA
Tadao TONUMA

Radiation Lab.
llJ~

3t :!J5
EE it -

dP.If

m t.t
!to]
7(

Jt
Ji

•
~

~

frJ
~

Fumio YAMASAKI,
Tatsuji HAMADA,
Takashi INAMURA,
Masaharu OKANO,
Yoshihiko TENDOW

w::

1Jo

~

1,(

EE 1t -T-

Yohko AWAYA
Akira HASHIZUME
Takeo KATO
Mitsuko OTA

Analytical Chemistry Lab.

1t
Jt

~

-Fa

m
lE

dP.If

Nobufusa SAITO,
Tadashi NOZAKI

5i'L 1:t~~Michi ARATANI

!fi:

3t ~
JJ£-T-

Fumitoshi AMBE
Mariko INARIDA~

Sadayo AMANO

Nuclear Chemistry Lab.
~

-Fa

m

ti $

~

-T-

1t

Nobufusa SAITO,
Shizuko AMBE,$

fffi{ijEE

Geochemistry Lab.
Makoto SHIMA,
Akthiko OKADA

7(

Jt

ft

~~

m5 fi

* Yukihiko HATTORI

~

#

iE

X.

~

;;L

Biochemistry I Lab.
EE

I=P

al

Yutaka G. TANAKARadiobiology Lab.
~

L.IJ

~

~t

L.IJ

~

Akira MATSUYAMA,
Shigeru KITA YAMA

Radiation Chemistry Lab.

4- t.tI=Pl§ff *'D ~Masashi IMAMURA,
Kazushiro NAKANO,00

Masao MATSUI
Hiroshi SEKI

90

Microbiology Lab.
Tsuneo KADA
Metal Physics Lab.
Ryukiti HASIGUTI,
Hideo SAKAIRI,

:E

~

fl5 ~

til

~

s 5t.

Kunihiko IWASAKI
Nobuhiro SHIOTANI

100.1

EE

1i! ttl

Takuya OKADA

Magnetic Materials Lab.
~

* 7't

:!ij

Mitsuo SUGIMOTO,

Precision Engineering Lab.
7.k ff J5 ilJl

Makio MIZUNO

Plastic Working Lab.
15 173 fl5 1l

Kunio MIYAUCHI

Radiation Monitors
Kugao KOODA,:!&: :<$:-eB

Ichiro SAKAMOTO

IE

Tadashi NOZAKI

Editors of the Progress Report
Kazuhisa MATSUDA,
Yutaka G. TANAKAIPCR Cyclotron Progress Report 1967
Jli~~-tt 1' 'J c "c / ~~-~ M1 • (1967) 1:1tt=n.llliJ

BBfD42-4'- (1967)

n.Flzsa~

ff Bt{;f042-4'- (1967)

ll,EI30B~ff~~1~~JfJEJijf
ft ~ ~

:tfi!

iff.

llY

~~

t~~!Ji!-~t.IE.lUIII*~IIII*~r~il"4775tftt!!.

1ti~iii.~ ~1~~JfJEJiJf-+t 1 1 0
LlJ~f{:lft:n .liliJ .PJT

:ff ~.& ~ t±

JL0484-62 1 1 1 1 tf
~ 0 /@;~~j:( ~
~

£

EfJ

Jt

~

ijiJ

~

JRJ?-t~-rttml.l1iflm1if!f*l!IT 1-42

~1iffi l.OOOPi

理化学研究所
埼玉県

北足立郡大和町