ISSN 0289-842X

RIKEN
Accelerator
Progress Report
vol.

22

理化学研究所the Institute of Physical and Chemical Research

RIKEN Acce/erGfor Progress Report 11 (Q) (6) (5)January-December U'71 (Q)(Q)JJ1 it ~ iff ~ pJi

Ihe Insfifute of Physical and Chemical Research
Wako-shi, Saitama, 351-01 JAPANEditors
S. AmbeK. Asahi

M. HaraT. Kambara

S. Kitayama

Y. Miyazawa

N. SakaiI. Shimamura

I. Tanihata

S. Yamaji

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

CONTENTS
Page

I.

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

II.

OPERATION OF ACCELERATORS1.

RRC Operation ............................................................

2

2.

RILAC Operation ............................ . .............................

4

3.

Cyclotron Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6

4.

Tandetron Operation

7

III.

RESEARCH ACTIVITIES

1.

Nuclear Physics
1.

Negative Pion Production in Heavy-Ion Collisions at
E1abl A = 42 MeV... . .................................................. . .....

8

2.

Search and Identification of New Isotopes ..................................

10

3.

Nuclear Studies with Secondary Radioactive Beams. . . . . . . . . . . . . . . . . . . . . . . . ..

12

4.

Projectile Fragmentation of an Extremely Neutron-Rich Nucleus
llLi at 0.79 Ge V I nucleon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

14

Nuclear -Ma tter Radii of 7Be and 7Li and the Astrophysical
S-Factors for Radiative Alpha-Capture Reactions ............................

16

Angular Momentum Transfer and Spin Alignment in the Reaction
4°Ar+ 209 Bi at 26 MeV l u ....................................................

18

7.

Multiple Coulomb Excitation of 157Gd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

20

8.

A Candidate for the K" = 4+Double-Gamma Vibrational Band
Head in 168Er .................................... . .........................

21

9.

Dipole Moment of 222Ra in the Two-Center Configuration ....... . ............

23

10.

Estimation of the Decay Rates of Cluster Emissions in 222Ra ............. . ....

25

11 .

Master Equations in the Microscopic Theory of Nuclear
Collective Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

27

Dissipative Collective Motion in the Non-Linear Dynamics of
the Nuclear Time-Dependent Hartree-Fock Theory ..........................

29

Microscopic Derivation of Transport Equation in theTime-Dependent Hartree-Fock Theory ............ . .........................

31

Average Partial Level Density Including the Effect of Residual
Interaction ................................................................

33

5.
6.

12.
13.
14.

2.

1

Atomic and Solid-State Physics

1.
2.

Cross Sections for Radiative Electron Capture Calculated by a
Relativistic Impulse Approximation- Formulation. . . . . . . . . . . . . . . . . . . . . . . . . . ..

35

Cross Sections for Radiative Electron Capture Calculated by a
Relativistic Impulse Approximation-Total and Differential
Cross Sections and Linear Polarization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

38

Page
3.

Circularly Polarized X Ray Emission Due to Radiative Electron
Capture ................................... '" ....... ... . .. . .... . . ....... . ..

40

Dynamic Electron Correlation in Double Ionization by Charged
Particle Impact and Photon Impact. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

42

Calculation of Stopping Powers for Energetic Heavy Ions in Solids
and Plasmas ..............................................................

45

6.

The Form Factors of the Hydrogenlike Atoms Revisited......................

47

7.

Gamma-Ray Spectrum Due to the De-Excitation of a Muonic
Molecule pa,u ..............................................................

49

State Densities and Ionization Equilibrium of Atoms in Dense
Plasmas.......................................... .. ........................

52

9.

Charge-State Distribution Measurements of 26-MeV l u Ar Ions. . . . . . . . . . . . . . ..

54

10.

Multiple Inner-Shell Ionization of Target Atoms by 0.8- 26 Me V l u
Heavy-Ion Impact ..........................................................
Resonant Transfer and Excitation (RTE) in Ge 3I + on H2 Collisions. . . . . . . . . . ..

55

4.
5.

8.

11.
12.

57

Studies on the Continuum X Rays Produced by Heavy-Ion-Atom
Collisions ........................ . ....... . ........ . ................ . .......

60

Target Thickness Dependence of Charge State Fractions of Ar Ions
after the Passage through C-Foil, CH 4 , and H2 ...................... . .... . ..

62

Charge Distributions of the Recoil Ions Accompanied with Multiple
Ionization of Heavy Projectile Ions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

65

15.

K-LL Auger Spectra of Nitrogen Projectiles...... .. ........................

68

16.

Analysis of the Mg IX 2s3d- 2s4f Transition of Beam-Foil Spectra ............

70

17.

Impact Parameter Dependence of Ne K-X Ray Emission in 10 MeV
N e7+ on N e Collisions ......................................................

72

18.

K Auger Spectra of Doubly-Excited Helium-Like Carbon ....................

74

19.

Observation of the Velocity Distribution of a Sodium Atomic Beam
Irradiated by a Resonant CW Dye Laser ........................... . ........

75

20.

Resonance Ionization Spectroscopy of Lantanoid Elements. . . . . . . . . . . . . . . . . . ..

77

21.

Incident Angle Dependence of AI-LVV Auger Spectra for Arl 2+
Impact ........................................................... . ........

79

Excitation of Convoy-Like Electrons by Glancing-Angle Incident
Heavy-Ion Impact .................... . ........................... . .........

81

23.

6INi Mossbauer Studies of Heusler Alloys. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

83

24.

57Fe Mossbauer Study on Superconductor Oxides ............................

84

25.

Motion of Kr-Bubbles in Krypton-Implanted Aluminum ......................

86

26.

Lattice Location Study on Kr Atoms in Aluminium by Means of a
Channelling Method ............................................ .. ....... .. .

88

Evaluation of Crystalline Quality and Irradiation Effects of a
Bi-Sr-Ca-Cu-O System High Transition Temperature
Superconductor by Rutherford Backscattering Spectroscopy ..................

91

RBS Investigation of N-Implanted AIN x Film Deposited on Silicon........ . ...

93

13.
14.

22.

27.

28.

29.
30.

3.

Hydrogen Trapping by Solute Atoms in Nb-Mo Alloys as Observed
by a Channelling Method ............................. . . . . . . . . . . . . . . . . . . . ..

97

3l.

Radiation Damage in Ion-Implanted CaF z Observed by Channeling. . . . . . . . . . ..

99

32.

PIXE-Channeling Analysis of Ga in the Ge Epitaxial Layer on a
Si Substrate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 100

33.

Chemical Erosion of Molybdenum Disulphide (MoS z) by Hydrogen
Plasma .................................................................... 102

34.

Charge Collection Measurements for the Study on Single Event Upset

35.

Correlation of Particle-Induced Displacement Damage in Si and
GaAs ...................................................................... 105

104

Radiochemistry and Nuclear Chemistry1.

Study on Incorporation of Carbon, Boron, and Oxygen in LEC-GaAs
Using Charged Particle Activation .......................................... 107

2.

Profiling of Light Elements in the Surface Layer of Solidby Means of the Elastic Recoil Detection .................................... 109

3.

Depth Profiling of Light and Heavy Elements-Application to the
Study on the Compositions of Anodic Oxide Films on Titanium-

4.
5.

4.

Page
RBS Investigation of N -Implanted Iron ...................................... 95

111

Behavior of a Releasing Agent Coated on a Heated Substrate as
Studied by Heavy-Ion Rutherford Scattering ................................ 113
Cross-Check of He Profiles by ERDA Method with 160 and 40 Ar
Beams .................................................................... 115

6.

Application of PIXE Analysis to Materials Sciences (I) ...................... 117

7.

Multielement Analysis of Human Spermatozoa by PIXE ...................... 119

8.

Mossbauer Emission Spectroscopy of 57Fe Arising from 57Mn ................ 121

9.

99Ru Mossbauer Spectroscopic Studies of Heusler Alloys. . . . . . . . . . . . . . . . . . . . .. 122

10.

Mossbauer Study of Organic Ruthenium Clusters ............................ 124

11.

y-Rays Perturbed Angular Correlation of 11lmCd in CdO, Cd(OH)z,
and a-Fe(2 at. % Cd)z03 .................................................... 125

12.

Preparation of No-Carrier-Added I11mCd for the Measurement of y-y
Perturbed Angular Correlation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 127

Radiation Chemistry and Radiation Biology

1.

High-Density Excitation by Heavy Ion: Techniques and Measurementof the Fast Emission Decay of BaF z Single Crystal. . . . . . . . . . . . . . . . . . . . . . . . .. 128

2.

LET Dependence of Cellulose Triacetate Film Dosimeter Response
for Ion Beams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 130

3.

Proton Irradiation Effects on Mechanical Properties of Aromatic
Polymers .................................................................. 131

4.

An Irradiation System for Biological Samples and Dosimetry at
RIKEN Ring Cyclotron .................................................... 133

Page

5.

5.

Parallel Plate Avalanche Counter for Dosimetry in the RIKEN
Ring Cyclotron Biology Facility ............................................ 135

6.

Combined Effect of cis-Diamminedichloroplatinum and Heavy Ions
on Mammalian Cells In Vitro .............................................. 137

7.

Dependence of the Strand Breakage in DNA on Radiation Quality ............ 139

8.

In Vitro Cell Transformation and Mutation by Heavy Ions

141

Instrumentationl.

Network in the RIKEN Accelerator Facility2.

Large Scattering Chamber at RIKEN Ring Cyclotron Facility ................ 147

3.

RIKEN Swinger-Spectrometer System ...................................... 148

4.

Facilities for Atomic Physics at RIKEN Ring Cyclotron. . . . . . . . . . . . . . . . . . . . .. 149

5.

Falling- Ball Irradiation System and the Hot Laboratory. . . . . . . . . . . . . . . . . . . . .. 150

6.

Target Transportation System for the One-Meter Diameter
Scattering Chamber ........................................................ 152

7.

Test of a Superconducting Secondary Beam Transport Systemwith Large Solid Angle (SLO) .............................................. 153

8.

Construction of a New Type of Low Energy Radioisotope Beam
Channel "SLOW" for Surface Studies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 155

9.

Performance of the Stop Detector for Time-of-Flight (T.O.F)
System .................................................................... 157

10.

Timing Property of New Type Time Pick-Up Detector ...................... 159

11.

Timing Properties of a Time-of-Flight Detector .............................. 162

12.

Compact and Gridless Channel Plate Start Detector .......................... 164

13.

A Position Sensitive Ionization Chamber .................................... 166

14.

Performances of a Two-Dimensional Position-Sensitive Silicon
Detector with a Large Effective Area ........................................ 168

15.

Calibration of Si-Detector Telescopes for Heavy-Ion Measurementsin Space .................................................................. 170

16.

Measurements of Some Characteristics of Thin Position-Sensitive
Silicon Detectors .......................................................... 172

17.

Test of a Si Two-Dimensional Position-Sensitive Detector for
Unbound Particle Measurements ............................................ 174

18.

Resonance Ionization Spectroscopy of a Fe Atomic Beam
Generated by a Spark Discharge Method .................................... 176

19.

Resonance Ionization Spectroscopy of Neutral Atoms Generated
by a Spark Discharge Method .............................................. 178

20.

Resonance Ionization Spectroscopy with a Sputtering Atomic
Beam Source .............................................................. 180

21.

A Radiation-Detected Optical Pumping System for the Achievementof Nuclear Orientation in Solids ............................................ 182

22.

An Attempt for a Local Loop Network Using an MC6854 ADLC .............. 184

144

23.

IV.

Page
Spectral Analysis with a Graphic Terminal .................................. 186

NUCLEAR DATAl.

Status Report of the Nuclear Data Group .................................... 187

2.

On the Cross Sections for the 12 C(p, pn)l1C Reaction .......................... 189

3.

The Nuclear Data for 13N Production ........................................ 191
Excitation Function Data for 15 0 Production ................................ 194

4.

V.

DEVELOPMENT OF ACCELERATOR FACILITIES

1.

Ion Accelerator Development2.

1.

Performance of New Grid Bypass Capacitors of the Final RF
Amplifier for RIKEN Ring Cyclotron. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 196

2.

Present Status of the Vacuum System for RIKEN Ring Cyclotron ............ 199

3.

Present Status of the Control System for RIKEN Ring Cyclotron .............. 200

4.

Status of Construction of the Injector A VF Cyclotron ........................ 202

5.

Magnetic Field Measurement of the Injector A VF Cyclotron .................. 203

6.

Design of the Central Region of the Injector A VF Cyclotron .................. 205

7.

Calculation of the Extraction Orbit for the Injector A VF Cyclotron

8.

Measurement of the Characteristics of a Resonator of the Injector
A VF Cyclotron ............................................................ 209

9.

Power Test of the RF System for the Injector AVF Cyclotron ................ 211

10.

Beam Buncher in the Injection Beam Line for the Injector AVF
Cyclotron .................................................................. 213

11.

Model Study of the Beam Rebuncher for the Injector AVF Cyclotron
and RIKEN Ring Cyclotron ................................................ 215

12.

Rotational Beam Scanner .................................................. 217

13.

Status of the RIKEN Electron Cyclotron Resonance Ion Source(ECRIS) for an Injector A VF Cyclotron ...................................... 219

14.

Basic Study of a Polarized 3He Ion Source by Laser Optical
Pumping. I ........................................... . .................... 222

15.

Basic Study of a Polarized 3He Ion Source by Laser Optical
Pumping. II ..... ',' ......................................................... 225

207

Synchrotron Radiation Source Developmentl.

A Preliminary Design of the 8 GeV Chasman-Green Lattice2.

Correction of the Closed Orbit Distortion (COD) for an 8 Ge V
Storage Ring (1) ............................................................ 231

3.

Correction of the Closed Orbit Distortion (COD) for an 8 Ge V
Storage Ring (2) ............................................................ 235

4.

Effect of Insertion Devices on Beam Dynamics of 8 Ge V Light
Source Storage Rings ...................................................... 238

227

VI.

5.

Page
Nonlinear Dynamics with Sextupoles ........................................ 242

6.

Particle Tracking in Harmonic Expanded Sextupole Fields

245

7.

Computer Code CATS: A Code for Sextupole Optimization

248

8.

Study of the Beam Injection to a 6 Ge V Storage Ring ........................ 253

9.

Beam Lifetime of the 6 Ge V Electron Storage Ring .......................... 257

10.

Beam Stability of the 8 Ge V Electron Storage Ring .......................... 259

11.

Design of the Sextupole Magnets for the 8 Ge V Storage Ring ................ 262

12.

RF System for 8 Ge V SR

13.

500 MHz Model Cavities for the 8 Ge V SR Ring

14.

Study of Multi-Cell Cavity with Inductive Coupling Slots for the
8 GeV SR Ring ............................................................. 271

15.

Calculation of the RF Electromagnetic Field for 8 Ge V SR Ring
Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 273

16.

Estimate of the Coupling Impedance for the Storage Ring .................... 276

17.

Pumping System for the 8 Ge V Storage Ring ................................ 279

18.

Stress Analysis of the Vacuum Chamber for the 8 Ge V Storage Ring .......... 281

19.

Pumping Characteristics of NEG Strip ...................................... 283

20.

Synchrotron Radiation Power Distribution at the 8 Ge V Storage Ring ........ 286

21.

Pressure Gradient Profile in the 8 Ge V Storage Ring ........................ 288

22.

Outgassing Rate of an Extruded Aluminum Alloy Chamber

290

23.

Thermal Analysis of the Crotch at the 8 Ge V Storage Ring

292

24.

Design of the Low-Frequency Cavity for the Synchrotron .................... 295

25.

Conceptual Design of Linac for the RIKEN SR .............................. 297

26.

Positron Injection System for RIKEN SR .................................... 299.................................................. 265............................ 268

RADIATION MONITORINGl.

Routine Monitoring of the Cyclotron, RILAC, and T ANDETRON

301

2.

Leakage- Radiation Measurements in the Cyclotron Building .................. 303

3.

Shielding Calculation for the Facility of RIKEN Ring Cyclotron
Using RILAC as an Injector ................................................ 305

4.

Radiation Monitoring in RIKEN Ring Cyclotron Facility .................... 307

VII.

LIST OF PU BLICATIONS ...................................................... 309

VIII.

LIST OF OUTSIDE USERS AND THEIR THEMES ........... ................... 321

IX.

LIST OF SEMINARS . ........................................................... 322

X.

LIST OF PERSONNEL

AUTHOR INDEX

324

1

I.

INTRODUCTION
H. Kamitsubo

A variety of collaborative research work using
heavy-ion beams was extensively carried out inthe past year in the field of nuclear and atomic
physics, nuclear and radiation chemistry, material engineering, and radiation biology at theInstitute of Physical and Chemical Research(RIKEN). The main facilities dedicated tothis collaborative research work are a 160 cm
cyclotron, a variable-frequency heavy-ion linac(RILAC), a 1 MV electrostatic accelerator(T ANDETRON), and a separated-sector cyclotron (RIKEN Ring Cyclotron, RRC). The 160 cm
cyclotron, which has been in operation for 23
years and used for studies in many research
fields, was decided to be shut down at the end of
fiscal 1989 (March, 1990).
RILAC has been operated as an injector to
RRC as well as an independent accelerator for its
own users. The beam time for the injection to
RRC was nearly a half of the total beam time of
RILAC. To reduce troubles associated with a PIG
source, we decided to introduce NEOMAFIOS,
an ECR soured developed at CEN, Grenoble,
for an ion source of RILAC; NEOMAFIOS
will be delivered at the end of 1989.
RRC has been in routine operation this year.
Ions of 15N, 2°N e, 22N e, 40 Ca, 64Z n , and 84Kr were
newly accelerated in this period. The highest
energy was 44 Me V lu for light heavy ions whereas the lowest energy was 10.6 MeV/u of 84Kr
ions. The lower energy can be obtained byincreasing the harmonic number of RRC. RRC
was shut down March through June to extend
beam lines to three new experimental halls. It
was reshut down again in December to extend
the beam lines to three other experimental halls.
Construction of the second injector, an AVF
cyclotron, was continued. Field mapping has been
finished and the beam dynamical calculationsof injection, acceleration and extraction orbits
were performed. The power test of an RF system
was successfully pursued. An ECR source for the
A VF cyclotron was completed and test operation showed its high-performance; it was used ontrial for experiments on atomic collisions.
From this year the RRC is open for outside users
and twelve teams of inside and outside users have
performed experiments. Studies on nuclear physics were carried out using RRC. Measurements ofhigh-energy y-ray and the subthreshold pion production cross sections were extensively performed.

Reaction cross sections by radioactive nuclei
were measured at Bevalac and RRC. The search
for new isotopes led to the successful identification of new proton-rich nuclei, 61Ga and 63Ge.
Theoretical studies of heavy-ion reactions andfission processes were performed on the basis oftransport calculations. Nuclear structure studiesof largely deformed nuclei were continued thisyear. Theoretical studies on atomic collision
processes have been pursued in connection withvarious phenomena such as radiative electron
capture at high energy, ionization processes ofhighly ionized atoms in gas and solid, and formation and decay of muonic molecules.
Experimental studies were carried out on
atomic collision processes and on beam foil
spectroscopy by using various kinds of ions at
RILAC and RRC. Energy spectra of photons andAuger electrons, charge-state distributions ofcolliding and recoiled ions, and angular distributions of X-rays and scattered ions were measured
to study the structure of highly ionized atoms,
the ionization processes, and charge transfer
process. Subnanosecond measurement of lightemission along a heavy-ion trajectory in gaseous
materials was also continued.
Mossbauer spectroscopy and perturbed angular correlation techniques were applied to thestudies on the properties of alloys, hightemperature superconducting oxide, and othermaterials. Analysis of the distributions of inplanted or dissolved impurities was continued byusing a Rutherford back-scattering method, elastic recoil detection method, and nuclear reaction
method. Activation analysis of light-element impurities in high-purity materials was continued
as before. PIXE analysis was applied to thecomposition analysis of medical samples. The
study of the radiation effects of heavy ions on
mammalian cells was also continued.
Construction of experimental equipments anddevices was continued. Performance tests andtest experiments were done for the devices completed in the preceding years by using highenergy beams from RRC.
Design and fabrication of a high-resolution
spectrograph and a projectile fragment separator (RIPS) were continued.
The R&D work on a high-brilliance synchrotron radiation source was continued and thedesign of an 8-Ge V storage ring was pursued.

2
RIKEN Accel. Prog. Rep. 22 (1988)

II.

OPERATION OF ACCELERATORS1.

RRC Operation

Y. Yano, K. Hatanaka, M. Kase, A. Goto, H. Takebe, H. Nonaka,
H. Isshiki,* R. Abe,* S. Otsuka,* H. Akagi,* and T. Ishikawa*in Table 1. Among them a 64Z n 20+ beam wasdifficult to tune, because its input beam intensity
to the cyclotron was not enough. Our noninterceptive phase measuring system, the timing
data from which are used for optimizing therf-phase of the rebuncher and creating the isochronous sector magnet field, require at least 100
enA to obtain the clear beam-phase data. Thus,
for tuning the machine, the idea of accelerating a
1605+ beam, which has a very close m/ q-value tothe 6 4 Zn 20+ beam and enough intensity, wasadopted. The isochronous field of the former
beam is biased by approximately 7.7 gauss to thelatter. This bias field was easily removed byadjusting a main coil current. It took nearly 17
hours since starting the sector field setting forthe oxygen beam till extracting the zinc beam.
An experiment group measured the beamenergy of 18 07+ by the TOF technique in use of
double PPAC's placed about 7.4 m apart fromeach other in the El hall, and obtained 41.46± 0 . 08 MeV / u. This beam was accelerated at an
rf frequency of 35 MHz and in a h = 9 mode. On

The 1988 RRC experiment programs acceptedby the nuclear and the other field users' PAC' swere carried out for 21 days in J annuary- Marchand for 36.5 days in September-November. In
these runs, with a few exceptions, the starting up
and tuning of the machine was done on Monday,
and the beam was offered to one or two groups
from Tuesday morning until Saturday morning
without changing the particle and its energy.
This year we had scheduled shutdowns threetimes: from mid March to June, in August and in
December. During the first period, the beam
distributing lines were extended to E2, E3, and E7
experiment halls, and new experimental setups
were installed in each. In July, after this shutdown, the study of beam transportation was
performed for every new beam line to obtain the
optimal-value data of magnet currents. On July
19 the extended radiation-controlled areas underwent the inspection by the authorities. In thefollowing two periods regular machine overhauls
were carried out.
New beams used for the experiments are listed
Table l.

New RRC beams in January-December 1988.
RILAC

12C
13C
14N
15N
16 0
40Ca
64Zn

RRC

F (MHz)QI

EI (MeV / u)

TN

Q2

35
35
35
20.187
35
25
28
25

3
3

2.48
2.48
2.48
0.648
2.48
l. 22
l.58
l.22

6
6
6
5
6
6
6
6

5
6
6
5
6
5
14
20

3

2
3

2
4
5

h

& (MeV/ u)i(enA)

9

42
42
42
10.65
42
20.6
26
20.6

200
50
200
100
50

9
9

10
9

9
9
9

(*)

10
10

F, RF frequency; Ql, Charge state; E 1, Beam energy; TN, Number of tanks; Q2, Charge state; h, Harmonic number;
E 2 , Beam energy; i, Maximum beam intensity during the experimental run.
(*) , This beam was accelerated for creating the isochronous field of 64Z n 20 + beam (in detail see the text).
* Sumijyu Accelerator Service, Ltd.

Y. Yana, et al.

the other hand, we estimated the beam energy to
be 41. 5 MeV l u from then-set coil current of theextraction bending magnet EBM2 whose radiusof curvature and magnetic excitation curve are
known. It was found that the estimation of thebeam energy from the EBM2 coil current is quite
reliable. The relation among the rf frequency F(MHz), harmonic number h, and beam energy E(Me V l u) is given by
A (F I h) 2= 1- (1 + E 1931. 5) - 2

Summing up the beam energies so far accelerated, we obtained the most probable value of A tobe 0.00552. This empirical expression gives thebeam energy within the error of ± l. 2% for
given F and h.
Some of the user groups demand that the lower
limit of the RRC beam energy decreases to about
5 MeV l u while the nominal value is 10. 6 MeV l u.

3This low energy beam can be obtained in a 20
MHz, h = 14 operational mode. But the present
rebuncher has a drift-tube structure suited to ah = 9 operational mode, and cannot give enoughbunching power for such a beam; a double buncher system is necessary. To investigate the othercrucial problems, we made a preliminary test for
a 132Xe 19 + beam of 0.33 Me V l u injection energy
corresponding to 5.3 MeV l u extraction energy.
The lifetimes of charge-stripper carbon foils of
10,.ug/ cm 2 and 20,.ug/ cm 2 were about 2 hours and5 hours in average, respectively. The vertical andhorizontal emittances were measured to be 79
mm emrad and 82 mm emrad, while they were 25
mmemrad and 28 mmemrad without the thicker
foil. The energy spread of the beam was acceptable. The study of resolving these problems isunder way.

4

RIKEN Accel. Prog. Rep. 22 (1988)

11-2.

RILAC Operation

Y. Miyazawa, M. Hemmi, T. Inoue, M. Yanokura, M. Kase, E. Ikezawa,
T. Aihara,* T. Ohki,* H. Hasebe,* and Y. Chiba

This year, RILAC has been in steady operation, and various kinds of ion beams were supplied for experiments. Table 1 gives the statistics
of operation. The total beam time increased by
16% compared with that of the last year, becauseof the shorter periods for overhaul and improvement. One day of the scheduled beam-time wascancelled owing to the trouble in a cooling pipeof the PIG source. Table 2 gives the beam time
for individual research groups. The total beamtime for RIKEN Ring Cyclotron (RRC) was 80days, which is about 27% longer than that for thelast year. Ions, 13C, N, 15N, 180, Ar, Ca, Zn, and Xe
accelerated by RILAC were injected to RRC.
Table 3 gives the statistics of the ions used thisyear. Ion beams of 22 species have been used forexperiments and 50% of total beam-time wasdevoted to Ar ions.
Table 1.

Statistics of operation for Jan. I - Dec. 31,

1988.

Beam time
Frequency change
Overhaul and improvement
Periodic inspection and repair
Machine trouble
Scheduled shut down
Total
Table 2.

Day

%

176
15
44
28
102

48.1
4.1
12.0
7.6
0.3
27.9

366

100

Beam time for individual research groups.
Day

%

31
17
0
15

17.6
9.7
0
8.5

Atomic physics
Solid-state physics
Nuclear physics
Radiochemistry and nuclear chemistry
Radiation chemistry and radiation
biology
Accelerator research
Beam transportation to RRC

12

6.8

21
80

11.9
45.5

Total

176

100

* Sumijyu Accelerator Service, Ltd.

Table 3.

Statistics of ions used in this year.

Ion

Mass

Charge state

C
C
C
N
N
N
N
Ne
Ne
Mg
Si
Ar
Ca
Ti
2n
2n
2r
Ag
Sn
Xe
Xe
Ta

12
12
13
14
14
15
15
20
20
24
28
40
40
48
64
64
90
107
120
132
132
181

3
4
3
2
3
1
3
2

3
3
3
4
4
3
3

5
4
5
5
7
8
7

Day

9

7
5
17
3
5
7
2

3
2

87
7
2

0.5
5.5
0.5
l.5
8
1
0.5

To investigate the possibility of beam acceleration in the frequency region above 40 MHz, C3+
and C4+ ions were accelerated at frequencies of
40 and 43 MHz, respectively. In the 43 MHz
operation, glass-epoxy rods used to support avariable vacuum capacitor at the output port ofa final amplifier were burned off by RF-heating
and were replaced by ones made of Teflon. This
year, we began accelerating Zr4+, Ags+, Sn5+,
and Ta7+ at 18 MHz.
We have made several improvements as follows:
1) The cooling tower and water pump for 500
k V injector operating used for the past elevenyears were replaced with new types.
2) Seven phase-lock circuits to suppress fluctuation in the phase of accelerating voltages
were equipped with a buncher and six
resonators. These circuits have been used forY. Miyazawa, et al.

extracting beams from RILAC very stably forlong time runs.
3) In exchange for a mechanical relay, a
MOS transistor switch was introduced in the coilcircuit of a vacuum contactor used in the primary power lines of the plate power supply forthe final tube. The exchange aimed to relieve a
shock of crowbar action to the power supply by
cutting off the primary lines with a minimum
delay after crowbar protecter firing. The delay
time was reduced to 35 ms from the inherent
delay of the vacuum contactor of 70 ms.
4) Since the control units (HP2240A), whichis connected through GPIB to the RILAC control
computer system, had been outmoded and over a5

period of guarantee to be replaced with theirspare parts, one of the five units was replacedtentatively with a new type. If it works satisfactory, all other units will be replaced.
5) An electrostatic quadrupole doublet lens
was installed at the exit of a 500 kV acceleratingcolumn. Thus, the beam intensity at the entranceof the linac was doubled by use of this lens.
6) This year, we observed frequent spark
discharges along the surface of the cylindricalinsulator housing of the 500 kV injecter power
supply, they were due to pollutant deposited on
the insulator surface. We cleaned the surface andsprayed silicone varnish on it to suppress the
sparks completely.

6
RIKEN Accel. Prog. Rep. 22 (1988)

11-3.

Cyclotron Operation

I. Kohno, K. Ogiwara, T. Kageyama, and S. Kohara

The 160 em cyclotron was operated on a 24 ha -day basis during the period XXIII from Jan. 1,
to Dec. 31, 1988. The statistics of the machine
operation time is shown in Table 1.
Table 2 shows the beam-time allotment tovarious activities during this period. Table 3
shows the distribution of the scheduled beamtime among various particles.
Table 1.

Table 2. Scheduled beam-time and research subjects
in period XXIII.

Ion source

BeamReading of the time

95,270.1

147 h
600
98
24

185 h
600
156
330

15

32

47

0
346

28
168

28
514

100,416.4 59,837.6

Radiochemical analyses
Radiation damage

0

236

236

of device for sattelite
Test of single event upset
Proton irradiationon thyristor

0
164

13
48

13
212

0

240

240

Total
Percentage in total

927 h
36.2%

1,634 h63 .8%

2,561 h100 %Outside users

Reading of the time
meter onJan. 06 1989 (h)97,380.8

Defference (h)2,110.7

103,421.5 61,453.9
3,005.1

1,616.3

Schedule in this period:
Beam-time
Overhaul and installation
Periodical inspection and repair
Schedule shutdown
Machine trouble

38 h
0
58
306

of semiconductor
Test of radiation detector

meter onJan. 06 1988 (h)Total

RI production for nuclear
and solid physics
Nuclear chemistry
Radiation biology
Radiation chemistry
Radiation damageof polymer
Radiation damage

Cyclotron operation in the period XXIII.
Oscillator

Heavy ion Light ion

Subject

176 d
60
28
97
5

Table 3. Distribution of the beam-time among
particles accerated.
Particle

(h)

(%)

p
3He 2+
4He 2+
12C4+
14N4 +.5+
160 5+
2°Ne 6+

606
380
648
29
786
16
96

23.7
14.8
25 .4
1.1
30.7
0.6
3.7

Total

2,561

100.0

7
RIKEN Accel. Prog. Rep. 22 (1988)

11-4.

Tandetron Operation

T. Kobayashi, H. Sakairi, E. Vagi, and T. Urai

The machine was operated for 184 days during
the period from Nov. 1, 1987, to Dec. 31, 1988.
The species of accelerated ions were IH, 4He, andlIB.
After about 7 year-operation without serious
trouble at the acceleration tubes and the
Cockcroft -W al ton circuit, frequent spar kings at
accelerating tube occurring in the early summer
made the high pressure SF 6 tank open during
July 13 and November 11 for replacement ofdeteriorated components. They were bleeder
resistors to distribute smoothly from the terminal voltage to a ground level, diodes to a generate the terminal voltage, and an rf step-up transformer. The other maj or trouble was the deterioration of a 40 kHz push pull oscillator and thedamage of a cesium ion gun due to cracking.
Experimental studies were carried out on following subjects.
(1) Rutherford backscattering spectroscopya) Behavior of Kr atom in Al (Metal Physics
Lab.)b) Lattice location and the disorder of Cu, Fe,or Cr-implanted CaF 2 (Semiconductors Lab. and

Surface Characterization Center)c) Composition of MoS 2 irradiated hydrogenplasma films (Plasma Physics Lab.)d) Characterization of AIN x (Surface Characterization Center)e) Crystalline quality evaluation and irradiation effect of a Bi-Sr-Ca-Cu-O system hightransition-temperature superconductor (Surface
Characterization Center and Surface and Interface Lab.)f) Determination of the crystallographic
polarity of c-BN (Surface Characterization Center and Surface and Interface Lab.)(2) Nuclear reaction analysisa) Lattice location of H in Nb-Mo alloys(Metal Physics Lab. and Surface Characterization Center)(3) Particle induced X-ray emission (PIXE)a) Lattice location of Ga in Ge (Cyclotron
Lab.)b) Basic study of PIXE and its application to
medical, environmental, archaeological, andmaterials science (Inorganic Chemical Physics
Lab.)

8
RIKEN Accel. Prog. Rep. 22 (1988)

III.

RESEARCH ACTIVITIES

1.

Nuclear Physics
1. Negative Pion Production in Heavy-Ion
Collisions at Elab / A = 42 MeV
T. Suzuki, T. Kobayashi, T. Kubo, T. Nakagawa, T. Ichihara,
M. Fukuda, K. Yoshida, and 1. Tanihata
NUCLEAR REACTION 12C(14N, 7(- ), E=42A MeV; measured incluSiVe)( 0'(7(-); deduced inverse slope constant, compared with theory.

Recently, significant attention 1-S) has been
devoted to the study of neutral pion production
in collisions of heavy ions near the absolute
threshold of 25A MeV. We report the first inclusive 7( - measurement for 14N + 12C at 42A MeV
incident energy. We believe that the measurement of charged pions provides us better pion
kinetic energy and angular resolutions. These
data are expected to show the collective effects
in nucleus-nucleus collisions.
The pion spectra have been observed to show
the exponential shape of which slope parameterdecreases with beam energy. An interesting
result was observed that the slope of the pionenergy spectrum is almost constant below thebeam energy of 60A Me V. However the errors
are still too large for qualitative discussion. We
expect that the systematic measurement of 7( provides better understanding on energy dependence of the slope factor.
The experiment was carried out at RIKEN
Ring Cyclotron (RRC) by using a large solid
angle (~200 mstr) spectrometer. The experimental setup consists of a rotatable C-type magnet,
MWPCs, and scintillation hodoscopes. The timeof flight (TOF), the energy-loss (L1 E) , and themomentum of emitted particles were measured.
A primary beam was led to a Farady-cup locatedat 3 m downstream from a target to reduce
backgrounds. Particle identification for negative
particles in a TOF - L1 E space is clean as shownin Fig. 1, where positive particles are also overlaid f<lr comparison. The electron backgrounds
were removed further by cut in a TOF-

Xl0
2.a~~~~~~~~~~~~~~-r. TOF vs dEldX

t.6. ~;. " .

..
.8

.6

1.0

.8

202

Xl0

Fig. 1. Plot of time-of flight vs. L1 E from 42A Me V
14N +C collisions. Time of flight is in terms of TDC
channels. One channel corresponds to 25 ps.
1000 . " . . - - - - - - - - - - - - - - ,

.~

§

100

E

~

10

o

100

300

200

re Kinetic energy (MeV)

Fig. 2. Pion (7r- ) kinetic energy spectrum in the laboratory frame integrated over en = 15 - 25 The straightline represents an exponential with an inverse slope
constant of 24. 5 MeV.
00•

momentum space. In total, 9,400 pions wereaccumulated.

9

T. Suzuki, et at.

Figure 2 shows a pion kinetic energy spectrum
obtained in the laboratory frame integrated over
81C= 15°-25°. The vertical axis is proportional to
df5/ dT1C. The error bars show only statisticalones. The solid line is obtained by fitting themeasured spectrum for T 1C =40-150MeV with theexpression: df5/dT1C=C exp(-T1C/To). The preliminary result indicates a remarkably large
inverse slope constant of To=24.5±O.9 MeV.
The value is consistent with those of 7[0 at 48A
MeV5) for 12C+ 12C and at 35A MeV4) for 14N +27 Al within error bars.
It was pointed out 4) that with decreasing beamenergy the experimental To values level off at aconstant value of To ~23 MeV. The obtained
value agrees with the same trend, which shows
clear contrast to that observed at higher beamenergies where the inverse slope factors were
found to decrease systematically from 27 to 22
MeV in the beam energy of 84-60A MeV as
shown in Fig. 3.
The inverse slope constants To of pion kinetic
energy spectra calculated within a single
nucleon-nucleon collision mechal}ism are in general much smaller than experimental ones; Refs.
6 and 7 quote To values about half as large as
observed at E 1ab / A=85 MeV. Calculations basedon mechanisms such as hot spot models 8 ) andthermal models,9) which explain integrated production cross sections well for beam energies
above 50A MeV, do not succeed to explain thetrend of the experimental data. To describe pion
production at the very low beam energies coherent mechanism is, therefore, necessary. The precise measurement of the source rapidity and theP.l (perpendicular momentum) distribution
together with the charged multiplicity is expect-

~ ..
/

/

/

/

/

/

/

/

/

'/

o

/

""

50
E

lob

100

(MeV Illucleonl

Fig. 3. Experimentally determined slope constants To ofpion kinetic energy spectra as a function of beamenergy / nucleon. Data (black circle) are taken from
Refs. 3-5. Present result is indicated by a white circle.
The dashed and solid lines correspond to predictions ofRefs. 8 and 9, respectively.

ed to give constraint to these models more qualitatively. Further studies on the beam energy
dependence are now in progress.
References
1) H. Heckwolf, et at.: Z Phys., A, 315, 243 (1984).
2) P. Braun·Munzinger, et at.: Phys. Rev. Lett., 52, 255(1984).
3) H. Noll, et at.: Phys. Rev. Lett., 52, 1284 (1984).
4) ]. Stachel, et at.: Phys. Rev. C, 33, 1420 (1986).
5) E. Grosse: Nucl. Phys., A447 , 611c (1985).
6) C. Guet and M. Prakash: Nucl. Phys., A488, 119c(1984).
7) R. Shyam and]. Knoll: Phys. Lett. B, 136, 221 (1984).
8) R. Shaym and]. Knoll: Nucl. Phys., A426, 606 (1984).
9) M. Prakash, P. Braun-Munzinger, and]. Stachel:
Phys. Rev. C, 33 , 937 (1986).

10

RIKEN Accel. Prog. Rep. 22 (1988)

111-1-2.

Search and Identification of New Isotopes

W.P. Liu,* M. Fukuda, T. Kubo, H. Kumagai, T. Nakagawa,T. Suzuki, M. Yanokura, 1. Tanihata, T. Ito,
T. Kashiwagi, J. Kikuchi, H. Yamaguchi, T. Doke,
H. Murakami, T. Yanagimachi, and N. Hasebe
NUCLEAR REACTIONS 9Be( 4°Ca, X)Y, E = 26.0 MeV / A, 12C(64Zn, X)Y,
E = 20.8 Me V / A; particle identification; search for new isotopes; measured
time of flight, energy loss, total energy and magnetic rigidity; deduced mass
number, atomic number, charge state and yield of fragments.
98e ( 40Ca, X ) Y

Particle identification is essential for all kindsof experiments in nuclear physics. A novel particle identification technique has been developed,
combining the use of a position sensitive silicondetector with a simple magnetic system. The
experimental setup includes a magnet system forrigidity (Bp) selection, a PPAC (Parallel Plate
Avalanche Counter) for TOF measurement incoincidence with an RF (Radio Frequency) signal, and a L1 E-E telescope in which the L1 E
counter is position sensitive. The detectors was
set at the focal plane of the magnet system. This
combination provided high efficiency measurements of time of flight, energy loss, total energy,
and magnetic rigidity and enabled the determination of the atomic number Z, charge state q, andmass A of produced fragments.
The final q spectrum is shown in Fig. 1. The
resulting resolution L1 q was 0.24 in FWHM at
q = 20, which can separate nuclei up to Z = 60;
the background was extremely low. The mass
spectra of some elements in a 9Be(4°Ca, X)Yreaction are shown in Fig. 2. The magnetic field
was set for optimizing the nuclei which A/ q =1.8. The resultant mass resolution L1 A was 0 . 34
in FWHM at A = 40. Therefore, the present
system is capable of identification of nuclei ofmass numbers up to A = 100 .
By using a 40Ca beam, we tried to identify 39SC.
Figure 3 shows the mass spectrum of Sc isotopes
and that the number of "would be" 39SC eventswas too small to confirm its existence. From theaverage of 5 runs, the upper limit of the yieldratio was established, Y (39SC) / Y (40SC) = 0.02.
* Permanent address: Institute of Atomic Energy, P.O.
Box 275-60, Beijing, China.

E = 26.0 MeV / A

AFTER SELECTION q = Z
4

10

3
Cf)

10

I-

Z

::>

8 10

2

10

6

10

14

18

CHARGE STATE (q)Fig. 1. Charge (q) spectrum of the totally stripped
charge state, in a 9Be(4°Ca, X)Y experiment, A / q=1.8
magnetic rigidity setting.

This indicates that the life time of 39SC is much
shorter than 130 ns which is the typical flighttime of fragments from a target to a detector.
This result is consistent with the recent 39SC massmeasurement. 1)
The search of new isotopes is a basic topic innuclear studies. The charge radii of an isotope
can be deduced by the ,B-decay half-life of its
mirror nuclei, for example. Up to now, the mirror
nuclei heavier than 59Zn have not been observed.
On the basis of previous experimental setup
and the particle identification technique, we have
performed an experiment which aims to search
proton-rich new isotopes such as 61Ga and 63Ge. A
beam of 64Zn20+ with 20. 8 MeV / A was provided
by RIKEN Ring Cyclotron at an intensity of 20
enA. The field of a dipole magnet was set toprovide the largest acceptance of 61Ga29+, whichis the charge state of 61Ga in the highert yield.

W. P. Liu, et at.

11

9 Be (40 Ca , X ) Y

E = 26.0 MeV / A
104 . . - - - - - - - - - , . . . - - - - - - - - - - - ,
K

10

~

3

q = Z = 21

E = 26.0 MeV I A

Sc

2

10

Z
:::>

o
()

10
(f)

IZ
:J

10

oo

CI

10

Fig. 3. Mass (A ) spectrum of Sc isotopes under the same
conditions as Fig. 1.
34

36

38

40

42

34

36

38

40

42

MASS (A)Fig. 2. Mass (A ) spectra of elements indicated. The
conditions are the same as Fig. 1.

nuclei with Z > 30. It can be used to study thebasic properties of nuclei.
Reference

The data of totally 30 h have been accumulated.
The searching of new isotope 61Ga and 63Ge
provides a effective means to produce mirror

1) c.L. Woods, W.N. Catford, L.K. Fifield, and N.A. Orr:

Nucl. Phys., A484, 145 (1988).

12
RIKEN Accel. Prog. Rep. 22 (1988)

111-1-3.

Nuclear Studies with Secondary Radioactive Beamsl)
1. Tanihata, K. Sugimoto, * S. Shimoura, K. Ekuni, **T. Kobayashi, N. Takahashi, *** and T. Shimoda ***(nuclear structure, radioactive beam, heavy-ion collisions.)

After the first measurement of interaction
cross sections at BEVALAC,2-4) it has been recognized that the structure of the nuclei far fromstability can be studied by using high-energy
beams of radioactive nuclei.
At high energies (;~400 MeV/ nucleon), theinteraction cross sections, 0'], (the total crosssections for change of proton and/ or neutron
numbers in the projectile) have been measured
for p-shell nuclei by a transmission method.
Recent development includes the refinement of
the cross sections for neutron drip line nuclei 11 Li
and 14Be and a new measurement for 17B at 790
MeV / nucleon. Measurements have also been
made at 400 MeV/ nucleon to verify the methodof extracting nuclear radii from the interaction
cross sections.
It was shown that the effective root-meansquare (rms) radii of nucleon distributions canbe deduced from 0'1 by using a Glauber model
calculation. 3,4) New data at 400 MeV/ nucleon
provides a mean to verify the method because thenucleon-nucleon cross sections at 400 MeV arevery much different from that at 800 MeV. The
observed cross section ratio of 11Li + C reaction

radii of Li and Be isotopes depend similarly on
N. It is seen that the majority of the rms radii ofp-shell nuclei are almost constant (2.3-2.4 fm)
except ones close to the neutron drip line. Large
increases in the radius from 9Li to llLi, from lOBe
to 11 Be, from 12Be to 14Be, and possibly from l5B
to l7B are observed. Now it seems common thatneutron drip line nuclei have large radius.
The isospin dependence of nuclear radii (forequal mass nuclei) were studied for the first time
for isobars of the mass number A = 6,7,8,9,11,
and 12.4) A comparison with Hartree-Fock calculations using a Skyrme potential showed that thedensity dependent force is important for reproducing the increase in radii for nuclei with alarge isospin. In general, Skyrme III potential
gives the best fit to the data, but it fails to
reproduce the radii of 11 Li and 11 Be.
A superior advantage of using radioactive
beam is its powerfulness for studying nuclei farfrom the stability line. Studies of interaction
cross sections and fragmentations reveal theinteresting behavior in the extremely neutronrich nuclei of He, Li, Be, and B nuclei. Firstly, the4.0 ,-------0,- -- - - - - ,0'1 (400) / 0'1 (800) =0. 91±0.03,------,• He

is consistent with the Glauber calculation (0.89)
employing only the change in nucleon-nucleon
cross sections. Therefore, the rms radii determined from 0'1 of two different energies are consistent with each other. Figure 1 shows values ofthe effective rms radii thus obtained up to date.
Now we glance at the radii obtained from theinteraction cross sections at 790 MeV/ nucleon.
Figure 1 shows the rms radii of nucleon distributions as a function of the neutron number (N).
The radii were determined by assuming theharmonic-oscillator model distribution. The

o Li
3.5 I-

• Be
o B

-

-

-

2.51-

2.0'--__-'-1_ _ _--'-1_

10

_

---'

15

Neutron Number* Faculty of Science, Osaka University.
** Kyoto University.
*** Faculty of General Education, Osaka University.

Fig. 1. The rms matter radii of light p-shell nuclei.
Nuclear radii are determined from the interaction
cross sections for radioactive nuclear beams.

1. Tanihata, et al.

radii of most neutron rich isotopes, sHe, llLi,
14Be, and 17B, are unusually large. An anomalously large size is also observed for llB. Secondly,
momentum spectra of fragments (9Li from llLi
and 12B from 14B) show extremely narrow component on the top of a wider component which
has a width consistent with that observed infragmentations of stable nuclei. 5)
Naively, these observations can be understoodas follows. In these extremely neutron rich nuclei
the separation energies of last two neutrons arevery small. The density distribution of such
weakly bound neutrons are expected to have along tail because the asymptotic wave function
has a form Cexp(-xr)/r), where (hX)2=2J.lB
and J.l is the reduced mass and B is the binding
energy. On the other hand, the momentum fluctuation of these last neutrons, which is a Fouriertransform of the radial wave function, F (p) = c /(p2+ x 2), are very small. Therefore qualitatively,
the observed large size and narrow width in the
fragment momentum distribution are consistent
with the existence of a long tail in the neutron
distribution (neutron halo). Because the momentum spread of 9Li is about a quarter of that of

13

normal Fermi gas,5) it is considered that the
decay constant of neutron halo in 11 Li is aboutfour times larger than that of normal nuclear
surface. However it is difficult to extract theamplitude of the neutron halo because the above
discussion is only valid near the surface of a
nucleus, and thus not sensitive to the wave function inside the nucleus. Sizes of the cross sectionsof a narrow and a wide component is expected toinclude information on the relative density
amplitude of the neutron halo.
References
1) published in Phys. Lett. B, 206, 592 (1988) and Nucl.

Phys., A488, 133c (1988).
2) 1. Tanihata, et al.: Phys. Lett. B, 160, 380 (1985).
3) 1. Tanihata, H. Hamagaki, O. Hashimoto, Y. Shida,
N. Yoshikawa, K. Sugimoto, O. Yamakawa, T.
Kobayashi, and N. Takahashi: Phys. Rev. Lett., 55,
2676 (1985).
4) 1. Tanihata, T. Kobayashi, O. Yamakawa, S.
Shimoura, K. Ekuni, K. Sugimoto, N. Takahashi, T.
Shimoda, and H. Sato: Phys. Lett. B, 206, 592 (1988).
5) T. Kobayashi, O. Yamakawa, K. Ornata, K.
Sugimoto, T. Shimoda, N. Takahashi, and 1. Tanihata: Phys. R ev. L ett., 60, 2599 (1988).

14
RIKEN Acce1. Prog. Rep. 22 (1988)

111-1-4.

Projectile Fragmentation of an Extremely Neutron-Rich
Nucleus llLi at 0.79 GeV /nucleon 1)

T. Kobayashi, O. Yamakawa, * K. Ornata, ** K. Sugimoto, *** and I. Tanihata(radioactive beam, heavy-ion collision, nuclear structure, llLi, neutron halo.]

A Newly developed technique to produce ahigh quality radioactive nuclear beams 2 ) provides a new possibility for the study of nucleon
density distribution and the momentum distribution of nucleons in unstable nuclei through theirprojectile fragmentation. In this report we present the measurements of fragments produced
from the projectile fragmentation of an extremely neutron-rich nucleus IILi at 0.79 GeV / nucleon
incident energy, and then show evidence for the
existence of a giant neutron halo in the neutron
distribution of the II Li nucleus.
Projectile fragmentation was extensively studied by using beams of stable nuclei. 3 ) An important finding is the regularity of a momentum
distribution of the projectile fragments. It was
found that the momentum distribution has aGaussian shape in the projectile frame, and thewidth of the Gaussian (1 is independent of target
mass and beam energy but depend on the mass
numbers of a projectile and a fragment in addition to a momentum fluctuation of nucleons
inside the nucleus. In other words, internal
momentum distribution can be determined fromthe measurement of projectile fragmentation. 4 )The transverse momentum distributions of thefragments of II Li by a carbon target were measured at 790 Me V / uncleon. Figure 1 presents thetransverse momentum distribution of 9Li, whichshows two-Gaussian structure in which a narrow
peak lays on top of the other wider peak. The
wider peak has a width (1wlde = 95 ± 12 Me V / c andthe other has a narrow width (1narrow = 23 ± 5
MeV / c. The two-component structure had notbeen observed in fragmentation of stable nuclei
and therefore is a new feature. The narrow peakindicates the existence of nucleons with anextremely small momentum fluctuation. The
O"Wide is consistent with the momentum fluctua* National Laboratory for High Energy Physics.
** Institute for Nuclear Study, University of Tokyo.
*** Faculty of Science, Osaka University.

tions of usual nucleons. The momentum width ofthe projectile fragment is related to the separation energy of last neutrons and thus written as(1 2 = u<e: >AF (As - A F)
(1)
As
where u is the atomic mass unit and <e: > is anaverage separation energy of the removed nu cleons. The observed narrow width gives <e: >=0.34±0.16 MeV which can be compared with theseparation energy of last neutrons: J E [ (I°Li +n) - (1ILi) ] =0 .96 ±0.1 MeV and J E [ (9Li+2n) - (llLi)] =0.19±0.10 MeV. The broad width,..0c(nuro w )=87±23mb

:;
-i

Cl..

c(widc)=lSO±29mb

25

~
b

""
~.
a

- 100

a

+100

P.1. [MeV/c]

28(b) 14Be + C _> 12Be + X (preliminary)

24

Vertical scattering angle

Fig. 1. Spectra of fragments from llLi (a) and 14Be(b). Both spectra show two components which are
specific only to the fragmentation of neutron dripline nuclei.

T. Kobayashi, et at.

on the other hand, gives <E)=6.0±1.5 MeV
which is roughly consistent with the normal
nucleon separation energy. Therefore it is considered that the narrow component is produced
by reactions in which weakly bound last twoneutrons are removed from llLi. The small
momentum fluctuation of last two neutron also
indicates the existence of a long tail in the neutron density distribution because a decay constant of the wave function on the nuclear surface
is a Fourier transform of the momentum distribution. Preliminary data on fragmentation of l4Be
also shows two-Gaussian structure as shown in
Fig. l(b). Therefore l4Be shows the same characteristics as llLi in the fragmentation spectrum aswell as the interaction cross sections. l)
It is suggestive to discuss the mechanism of
producing two components in the fragmentation
spectrum. Under the assumption that llLi is composed of a core of 9Li and two loosely boundneutrons which have an extended tail in theirdensity distribution. When the impact parameterof collision is small and core neutrons are
removed, a probability of producing 9Li would bevery small because loosely bound outer twoneutrons ?ire most likely removed simultaneously. Therefore 9Li is mostly produced in very
peripheral collisions.
If these two neutons are kicked out simultaneously in a peripheral collision, it is certainthat 9Li has small momentum fluctuation as
discussed before. On the other hand, when only
one of them is removed by the collision, themomentum width would be wider. It is due to the15

processes involved in the collision; first, the separation energy of one neutron is larger and thus
gives wider momentum fluctuation in a prifragment lOLi. Then, additional broadening
occurs due to the level width of lOLi and recoils ofneutron emission. Therefore, the narrow component is produced only when two neutrons are
removed simultaneously from llLi.
In a peripheral collision, only a small geometrical overlap occurs of the projectile and the target. Therefore, the simultaneous collision probability of both neutrons with target nucleons isvery small if these neutrons are not correIa ted. A
visibly large amount of the cross section of thenarrow-component suggests the existence ofstrong correlation between two outer neutrons.
Quantitative discussion on the relative strengthis necessary to understand the structure of outerneutrons.
References
1) published in Phys. Rev. Lett., 60, 2599 (1988) and Nucl.

Phys., A488, 133c (1988).
2) I. Tanihata: Hypeifine Interact., 21, 251 (1985); I.
Tanihata, H. Hamagaki, O. Hashimoto, S.
Nagamiya, Y. Shida, N. Yoshikawa, O. Yamakawa,
K. Sugimoto, T. Kobayashi, D.E. Greiner, N. Takahashi, and Y. Nojiri: Phys. Lett. B, 160, 380 (1985);
I. Tanihata, H. Hamagaki, O. Hashimoto, Y. Shida,
N. Yoshikawa, K. Sugimoto, O. Yamakawa, T.
Kobayashi, and N. Takahashi: Phys. Rev. Lett., 55,
2676 (1985).
3) D.E. Greiner, et at.: Phys. Rev. Lett., 35, 152 (1975).
4) J. HUfner and M.e. Nemes: Phys. Rev. C, 23, 2538
(1981).

16
RIKEN Accel. Prog. Rep. 22 (1988)

111-1-5.

Nuclear-Matter Radii of 7Be and 7Li and the Astrophysical
S-Factors for Radiative Alpha-Capture Reactions
T. Kajino,* H. Toki,* K-1. Kubo,* and 1. Tanihata(nuclear structure, astrophysical reaction, radioactive nuclei. J

The nuclear-matter radii of 7Be and 7Li measured in high-energy heavy-ion reactions havebeen calculated and applied to estimate the astrophysical 5-factors for the 3He (a, y) 7Be and3H (a , y) 7Li reactions. The absolute 5(0) values
in ke V b are constrained to be 0.36 < 5(0) < 0.63
and 0.083 < 5(0) < 0 .15 for the 3He (a, y)7Be and3H (a , y) 7Li reactions, respectively.
A recent experiment 1,2) of high-energy heavyion reactions using exotic-isotope beams provides a new tool for the study of the nuclear
structure of light elements He, Li, and Be including serveral radioactive isotopes. The hadronicmatter radii were determined from the measured
interaction cross sections in the experiment. The
data for unstable 7Be and 7Li nuclei among themare of particular interest for an application toastrophysics: The formation reactions of these
nuclei, i.e., 3He(a , y)7Be and 3H(a , y)7Li, arepresumed to take one of the keys to resolve themissing solar-neutrino problem 3.4 ) and the
problem S,6) of big-bang production of 7Li.
Although a number of experiments have been
done to measure the reaction cross sections
repeatedly, some of them differ appreciably fromone another, casting a doubt on the theoreticalprediction of the solar neutrino counting rate in
the 37CI or primordial 7Li abundance for which
the above two reaction rates are important input
parameters. In a recent theoretical study7) of
these reactions, a very strong correlation was
found between the calculated reaction rates andthe nuclear sizes of 7Be and 7Li. The measured
matter radii, in particular, of unstable 7Be makean independent estimate of the reaction rates by
the use of the theoretical correlation between
them. The purpose of this report is to constrain
the absolute strength of the reaction rates (often
expressed as astrophysical 5-factors) for the
3He(a, y) 7Be and 3H (a, y)7Li reactions.
A microscopic cluster model wave function 7)* Faculty of Science, Tokyo Metropolitan University.

was adopted in the present calculation of thematter radii and reaction rates. It was found that
almost all existing data on the binding energies,
the electromagnetic structures of 7Be and 7Li,
and the scattering amplitudes for alpha + (A = 3)
systems are explained systematically by the useof the modified Hasegawa-Nagata force. B)
The experimental data for 7Be and 7Li show
almost identical matter radii within their error
bars although the proton and neutron matterradii between the two isobars show appreciable
difference as shown in Fig. 1. The theoretical
calculation agrees with all these data fairly well.
A close comparison between theory and experiment, however, shows different charge dependence from each other.
Performing the calculation of both quantities,
5-factors and nuclear sizes, by using many different types of effective interactions, one finds linear correlation between the two observables.
Using the observed RMS matter radius of 7Be,
we obtain the following constraint on the absolute strength of the astrophysical 5 -factor:(1)0.36 < 5(0) < 0.63 keY b

This is the first estimate of the 5-factor for
3He (a, y) 7Be by using the data of unstable 7Be
(frn)
2 .7

RMS RADII OF
MATTER

2 .6

PROTON
MATTER

7Li AND
NEUTRON
MATTER

7 Be
CHARGE

t -

2.5
2.4
2 .3

r! .-

•

r--

2.2

Li

Be

Li

Be

li

Be

li

Be

Fig. l. Comparison of the charge and matter radii ofthe A = 7 nuclear systems between theory and experiments. Experimental values are taken from Ref. 2( . ) and Refs. 9- 11 (D) .

T. Kajino, et at.

nucleus. In the estimate we have considered theexperimental error of the observed matter radius
and a ± 20% uncertainty for the linearity of thetheoretical correlation. The present estimate (1)is consistent with the range
S(O) =0.56±0.03 keY b(2)which was determined by extrapolating the
S-factors for the 3He (a, y) 7Be reaction observed
at higher energies to zero energy, by assuming
the energy dependence of the 5-factor calculated
in the microscopic cluster model. 10)
As for the 3H (a , y) 7Li reaction, a similar
analysis gives a constraint
0.083<5(0) <0.15 keY b(3)This range is consistent with the previous values
determined by direct capture gamma-ray experiments; Griffiths' data 11) extrapolated to zeroenergy by assuming the energy dependence of thecalculated S-factor10) lead to S(O) =0.100±0.025
ke V b 9 ) and Schroder's data 12) with the same
theoretical 5-factor lead to 5 (0) = 0 . 134 ± 0 . 020
keY b. Although Schroder, et at. have obtained
another value S(O) =0.163±0.024 keY b. basedon another theoretical energy dependence of the
5-factor calulated by Williams and Koonin,13) the
energy dependence referred to proved to be incorrect. The inferred value 0.162 ± 0 . 024 ke V b isout of range of the present study.6)
We comment that the primordial 7Li abundance calculated in the big-bang model in Ref. 9
is reliable within +40% and -18% error, if
combined with the present constraint 6) on 5 (0)for the 3H (a, y)7Li reaction.
To summarize, we have calculated the charge,

17

proton and neutron matter radii of 7Be and 7Li ina microscopic cluster model. The theoreticalmatter radii show an interesting difference
between 7Be and 7Li though the observed radii
are almost equal to each other. We have also
estimated the astrophysical S-factors for the
3He (a, y) 7Be and 3H (a, y) 7Li reactions with thehelp of the measured matter radii of 7Be and 7Li.
The theoretical relation between the S-factor
and the matter radius has been used. The present
result strongly constrains the absolute strengthof the S-factors which affect the solar neutrino
counting rate in 37Cl and the big-bang nucleo synthesis of 7Li.
References
1) I. Tanihata, et at.: Phys. Rev. Lett., 55, 2676 (1985).
2) I. Tanihata: Proc. XI lnt. Conf. Particles and Nuclei(Kyoto, 1987), to be published in RIKEN Accel. Facit.
Rep., RIKEN-RF-NP-59.
3) J.N. Bahcall, et at.: Rev. Mod. Phys., 54, 767 (1982).
4) R. Davis, Jr., B.T. Cleveland, and ].K. Rowley: Conf.
Interactions between Particles and Nuclear Physics(ed. R.E. Mischke), AlP, New York (1984).
5) S.M. Austin and C.H. King: Nature, 269, 782 (1977).
6) ]. Yang, et at.: Astrophys. ]., 281, 493 (1984).
7) T. Kajino: Nucl. Phys., A460, 559 (1986).
8) F. Tanabe, A. Tohsaki, and R. Tamagaki: Prog.
Theor. Phys., 53, 677 (1975).
9) T. Kajino, H. Toki, and S.M. Austin: Astrophys. ].,319,531 (1987).
10) T. Kajino and A. Arima: Phys. Rev. Lett., 52, 739(1984).
11) G.M. Griffiths, et at.: Can. ]. Phys., 39, 1397 (1961).
12) U. Schroder, et at.: Phys. Lett. B, 192, 55 (1987).
13) R.D. Williams and S.E. Koonin: Phys. Rev. C, 23, 2773
(1981).

18
RIKEN Accel. Prog. Rep. 22 (1988)

111-1-6.

Angular Momentum Transfer and Spin Alignment
in the Reaction 4°Ar+ 209 Bi at 26 MeV /uN. Iwasa, K. Ieki, Y. Ando, H. Fujiwara, K. Hata, M. Ishihara,
S.C. Jeong, S.M. Lee, T. Motobayashi, T. Mizota, H. Murakami,
T. Murayama, Y. N agashima, Masahiko Ogiwara, Mitsuhiko Ogihara,
S. Okumura, Y.H. Pu, J. Ruan (Gen), S. Shibuya, and S. Shirato
NUCLEAR REACTION 209Bi+ 4°Ar, E(40Ar)/ A=26 MeV / u;
[ measured fission fragment angular distribution, angular 1
momentum transfer, spin alignment.

In intermediate heavy-ion reactions, projectile
fragmentation is considered as a dominant process. In the present study, we show that multinucleon transfer process also contributes to theemission of projectile-like fragments at energy of
26 MeV l u. As is well known in lower energy
heavy-ion reactions, large angular momentum
transfer and spin alignment accompany withsuch transfer reactions. We measured fission
fragment angular distributions in coincidencewith projectile-like fragments to investigate theangular momentum transfer process.
The experimental setup was similar to a previ0us one. 1) A 26 MeV I u 40 Ar beam from RIKEN
Ring Cyclotron bombarded a self-supporting
209Bi foil of about 1 mgl cm 2 in thickness. A
counter telescope to detect projectile-like frag-ments was located at 10° from the beam axis andat 20 cm from the target. The telescope consistedof three (.a E-E-E) silicon surface-barrier detectors of 50, 1,500, 1,500,um in thickness collimated by using an aperture 8 mm wide and 14 mm
high. The detection angle was more forward
than the previous time and the dynamic range ofthe counter was set wider so as to measureheavier fragments. Various projectile-like fragments (3 ~ Z ~ 18) were observed. Their velocity
were 70-80% of that of the beam. Coincident
fission fragments were measured with nine thinsurface-barrier detectors covering a wide angu1ar region. They were located at 10 cm from thetarget and collimated by an aperture 7.5 mm indiameter. A sizable fraction of the projectile-like

101L.L.J.--LJ......J......I.....l....1-'--'--'--'-'-~~

o

30

60

90 120 150 180
ill (deg.)

Fig. 1. Angular distribution of fission fragments
coincident with projectile-like fragments (13 ~ Z ~17). The abscissa denotes the angle between thedetector and the recoiling direction of the fissile
nucleus. Dotted line shows l / sind> curve. The dashed line shows the case where spin distributes
uniformly in the y-z plane. The solid line shows thecase where completely aligned spin component wasalso included (see text).

30

60

90

9 c ••. (deg.)

Fig. 2. Out of plane angular distributions of thefission fragments for three c/> angular ranges.
Meanings of the dashed and solid curves are thesame as in Fig. 1.

N. Iwasa, et at.

fragments cross section was seen to be coincident
with the fission fragments. Angular distributionsof the fission fragments were measured at 23
directions both in and out of the reaction plane.
The fission fragments were well discriminatedfrom evaporative light particles by the relation
between the energy loss in the detector and thetime of flight from the target to the detector.
In Figs. 1 and 2, typical angular distributionsof fission fragments coincident with projectilelike fragments (13::;;: Z::;;: 16) are displayed in therest frame of the recoiling fissile nucleus. The
z-axis and x-axis are defined as a reaction plane
normal and the recoil direction of the fissile
nucleus, respectively. As the detection angle
dispersed widely both in () and </>, the angular
distribution is sorted in an angle qJ with respect
to the x-axis (Fig. 1) . The angular distribution in
qJ is very asymmetric and strongly peaked in the19backward direction. The angular distribution
roughly has a shape of l / sinqJ (dotted curve),
which may correspond to the fusion-fission-likeprocess between the remnant of the projectile
and the target. Assuming that the spin distributes
uniformly in the y - z plane (dashed curve), we
estimated that transferred angular momentum tothe target should be larger than 60 h. The angular distribution is almost independent of (), butsomewhat deviates from the dashed curve. In
Fig. 2, the out-of-plane angular distribution isshown for three angular ranges of cP. An 8%
addition of a completely aligned spin component
to the uniform spin distribution (solid lines in
Figs. 1 and 2) gave a little bit better fit.
Reference
1) K. Ieki, et at.: RIKEN Accel. Prog. Rep., 21 , 9 (1987).

20
RIKEN Accel. Prog. Rep. 22 (1988)

111-1-7.

Multiple Coulomb Excitation of 157Gd

M. Oshima, T. Inamura, A. Hashizume, H. Kusakari, M. Sugawara,
E. Minehara, * S. Ichikawa, * and H. Iimura *NUCLEAR REACTIONS 157Gd(58Ni, 58Nity) , E = 240 MeV;
measured E y , nuclear lifetimes; recoil distance method;
B(M1) signature dependence.

l

In a series of the study of rotational perturbation effects in odd nuclei, 1- 4) the nucleus 157Gd has
been multiply Coulomb-excited up to the 23/ 2state. Rotational band members above the 15/ 2state have been established for the first time in
157Gd.
The experiment was carried out using a Ni
beam of 240 Me V obtained from the JAERI tandem accelerator. Targets used were selfsupporting metallic 157Gd, which was 93.3% isotopically enriched: one was about 30 mg/ cm 2 , andthe other about 3 mg / cm 2 in thickness. Deexcitation y rays were measured with Compton
suppressed Ge detectors by using the thick target;
y-y coincidences, y-ray angular distributions,and nuclear lifetimes were also measured. The
nuclear lifetimes were determined by a recoil
distance method using the thin target.
As is shown in Fig. 1, energy levels are clearly
dependent on the signature r, which is defined as 5)r =exp( - ina)

11

2.0

~

I I I I II~I.......

i1.0.......

.....

6
CQ

0.0

7

9

11 13

15 17 19 21 23

222222222
I

Fig. 2. Ratios of B(Ml ; 1-41 - 1) to the rotational values
are plotted as a function of'spins.

where a = -1 / 2 for 1 = 1/ 2, 5/ 2,9 / 2,"', anda = -1/ 2 for 1 = 3/ 2 , 7/ 2, 11/ 2,···. On the contrary, reduced M1 transition probabilities, B(M1;
I ~ 1-1) , do not show significant dependence on
the signature (see Fig. 2). Usually the latter ismuch sensitive to the signature, compared to theenergy level.
The present result suggests that the configuration mixing strongly affects the signature dependence of B(M1) values, because B(M1) should be
microscopically more sensitive to the wave functions of states concerned than the level energy.
References
1) M. Oshima, E. Minehara, M. Ishii, T. Inamura, and A.

+[521]

Hashizume: Nucl. Phys., A436 , 518 (1985).
2) E. Minehara, M. Oshima, S. Kikuchi, T . Inamura, A.
Hashizume, and H. Kumahora: Phys. R ev. C, 35, 858

8
21

2

~

2

2 J2

Fig. 1. Energy difference vs . f2 within the 3/ 2- [521J
rotational band of 15 7Gd. Closed circles denote thesignature r = - i , and open ones the signature r = + i.
. . Japan Atomic Energy Research Institute, Tokai.

(1987).

3) M. Oshima, E. Minehara, S. Ichikawa, H. Iimura, T.
Inamura, A. Hashizume, H. Kusakari , and S. Iwasaki:
Phys. R ev. C, 37, 2578 (1988).
4) M. Oshima, E. Minehara, S. Kikuchi, T. Inamura, A.
Hashizume, H. Kusakari, and M. Matsuzaki: Phys.
R ev. C, 39, 645 (1989).
5) M.J.A. de Voigt, J. Dudek, and Z. Szymanski: Rev .
Mod. Phys., 55, 949 (1983).

21
RIKEN Accel. Prog. Rep. 22 (1988)

111-1-8.

A Candidate for the K n =4 +Double-Gamma Vibrational Band
Head in 168Er

M. Oshima, T. Inamura, A. Hashizume, H. Kumagai, H. Kusakari,
M. Sugawara, E. Minehara, * H. Iimura,* and S. Ichikawa *NUCLEAR REACTIONS 168Er(S8Ni, S8Ni'y), E=240 MeV; )( particle-y coincidences; double-gamma vibrational state.
Whether double-gamma vibrational states
exist or not in deformed nuclei is currently thecentral problem for elucidating the collective
excitation of nuclei. H ) Nevertheless, no unambiguous evidence for the double-gamma vibrational
states in deformed nuclei have so far been provided experimentally. The present result might
be the first observation of y transitions from the
double-gamma vibrational band head (In = 4~,
K1!' = 4+) to the single-gamma vibrational band
members (F = 2 ~ , 3 ~ , 4~ , Kn = 2+).
168Er was multiply Coulomb-excited with a S8Ni
beam of 240 MeV obtained from the JAERI tandem accelerator. The target 168Er was a selfsupporting metallic foil of l. 5 mg/ cm 2 in thickness (95% isotopically enriched). Deexcitation yrays were observed with four Ge counters incoincidence with four PPACs (Parallel Plate

Avalanche Counter) which detected recoiled target atoms and scattered projectiles, providing
the position signals of detected particles. The Ge
counters were placed at ± 45 and ± 135 to thebeam direction, 10 cm from the target. The
PP ACs were placed symmetrically with respect
to the beam, surrounding the target, so that they
covered forward as well as backward angles.
The size of PP AC was 10 cm x 10 cm, and the
distance between the center of the PP AC window
and the target was 7 cm.
The observed y-ray spectra were corrected for
Doppler shifts kinematically by using the position signals of the particles registered. Figure 1
shows the Doppler corrected y-ray spectrum; yrays were observed in coincidence with projectiles scattered in the forward direction to seehighly excited states with relatively low spins.
08~ 10 .... 3,...;.......

~~ 10.... 2

8

10 .... 1

10 .... 0

1000

1500

2000

Ey (keV)Fig. 1. Doppler corrected y-ray spectrum observed in coincidence with forwardly
scattered projectiles in Coulomb excitation of 168Er.
* Japan Atomic Energy Research Institute, Tokai.

022M. Oshima, et al.

In addition to y rays from the ground-state
rotational band and the single-gamma vibrational band, y rays of interest were observed:
1.452(3), 1.376(6), and 1.276(4) MeV around a
giant peak of the 2 + ~0 + (1.4544 MeV) transi tion in the projectile 58Ni. If they are of transitions from the double-gamma vibrational bandhead to the single-gamma vibrational states In =2~, 3~, and 4~ respectively, the position of theband head is placed uniquely at 2.272 (4) MeV
within experimental errors because the enegy
differences between y rays coincide with thosebetween the well-established single-gamma vibrational states concerned. 5) This position iswithin the theoretical prediction.1)

The present result does not support theassumption that the double-gamma vibrationalband head should be at 2.056 Me V on the basis of(n, y) measurements. 5) Further investigation isunder way to confirm the present interpretation.
References
1) M. Matsuo and K. Matsuyanagi: Prog. Theor. Phys. ,74, 1227 (1985) ; 76, 93 (1986) ; and 78, 591 (1987).
2) N. Yoshinaga, Y. Akiyama, and A. Arima: Phys. Rev.
L ett., 56, 1116 (1986).
3) V.G. Soloviev: E4 -87 -795, Dubna (1987).
4) M.K. lammari and R. Piepenbring: Nucl. Phys., A487,
77 (1988).
5) V. S. Shirley: Nuc!. Data Sheets, 53, 223 (1988).

23

RIKEN Accel. Prog. Rep. 22 (1988)

111-1-9.

Dipole Moment of 222Ra In the Two-Center Configuration
S. Yamaji and N. Yoshinaga
NUCLEAR STRUCTURE octupole deformation, J[ two-center shell model.

The nuclei in the actinide region have characteristic features essentially different from thosein other regions: one is strong E1 enhancement
and the other is I4C decay. In order to explainthese characteristics, several models such as theoctupole deformation model I) and the Vibron
model 2) were proposed.
Our motivation is to compare these models andfind out which is more suitable to describe thenuclei in this region. We analyzed 222Ra by using
the two-center shell model. In Fig. 1 the definednuclear shape of 222Ra is shown. The radii RI andR2 are determined by imposing the conditions
that the volume ratio (RJ R 2 ) 3 is equal to themass ratio (A J A 2 ) and that the total volume isconserved. Here, Al and A2 are the mass numbers of the two fragments.
It is known experimentally that the electric
intrinsic dipole moment of 222Ra is at most 0.5 e
fm. Therefore, we try to see how large themacroscopic dipole moment Ds is in our model byusing Strutinsky's method. 3 )First, we calculated the total energy
as afunction of the separation Zo for deveral cluster

configurations by the microscopic-macroscopic
method. 4 ) The set of parameters given on the firstrow in the Table 1 of Ref. 4 is used in the present
calculation.
r -- - -- - r - - - - - , - -------, 60

1 - - - - - + - - - - : : : ; 1 : : : : - - - - - - 140

'-

1'"

~----'--L--; 3~Mg + '~OS"-'---~.

~ Ne +~Pt f-.!l.

~..L..-.l.....-D-..{

20':O+ ~ H g_

T"--.J:::::.-_.-I.

':C +~Pb~

I ~~:'--L.......J-+IO ':Be + 'i! Po

eat

to (fm)eot

Fig. 2. Total energyof 22 2Ra as a function of
the separation Zo for various combinations of clusters.
7. -- -- - - -- - - -- - ,6

5

Fig. 1. Nuclear shape. Zl and Z2 are the centers of
two clusters. The separation Zo is defined byzo =Zl - Z2 - Zc, where Zc is the center separation at theconfiguration where the small cluster just appearson the 222Ra surface.

o2~ R a - ~~ Ca + l~Er

23456
2 0 (fm )Fig. 3. Macroscopic dipole moment of 222Ra as afunction of Zo from the configuration of the parent
nucleus to the contact configuration.

24

S. Yamaji, et al.

We have found that the minimum of the totalenergy exists around Zo = 2 . 5 fm in the ~gCa +l~~Er configuration as shown in Fig. 2. We show
the macroscopic dipole moment Ds 3) as a functionof Zo for the ~gCa + l~~Er configuration in Fig. 3.
The dipole moment of the minimum point (Ds =0.46 e fm) well reproduces the observed value.
The corresponding deformations are /32 = 0.18,/33 = 0 .16, /34 = 0.13, /35 = 0.10, /36 = 0.07, where /32
and /33 are nearly equal to /32 = 0 .12, /33 = 0 .11

obtained by Leander.I}
References
1) G.A. Leander: Proc. Niels Bohr Centenial Conf. on'Nuclear Structure 1985' (eds. R.A. Broglia, et al.)Copenhagen, p. 249 (1985).
2) F. Iachello: Phys. Lett. B, 160, 1 (1985).
3) V. Strutinsky:]. Nucl. Energy, 4, 523 (1957).
4) P. MeHler and J.R. Nix: Nucl. Phys., A361 , 11 (1981).

25

RIKEN Accel. Prog. Rep. 22 (1988)

111-1-10.

Estimation of the Decay Rates of Cluster Emissions in 222Ra
S. Yamaji and N. Yoshinaga(NUCLEAR STRUCTURE radioactive decay.]

Sandulescu, et al. I ) predicted the emission ofvarious heavy clusters from some paticular parents such as Ra and Th nuclei on the basis of avery simple calculation of penetrability. In thisspirit, Rose, et al. and other groups2) reported
the discovery of 14C radioactivity; Shi, et al. 3 )tried to explain measured branching ratios.
However, in these calculations,I.3) a potential
barrier was approximated by polynomials without any theoretical foundation. It is very important to study the dependence of the barrier on the
deformation in a quantum tunneling calculation.
We calculated the barrier as realistically as
possible by a microscopic-macroscopic method. 4)
As a deformation parameter, we intoduce a center separation Zo describing the two-center spherical parametrization of the shape shown in Fig.
1. The radii RI and R2 are determined by thefollowing conditions:a) The volume ratio (RII R2) 3 equals to themass ratio (All A 2). where Al and A2 are themass numbers of two fragments.
b) The total volume is conserved.
We can calculate the potential barrier &.ot (zo)in the configurations of a parent nucleus and theFig. 1. Nuclear shape. Zl and Z2 are the centers of
two clusters. The separation Zo is defined by Zo =Zl - Z2 - Zc, where Zc is the center separation at theconfiguration where the small cluster just appearson the 222Ra surface.

well-separated fragments by using the
microscopic-macroscopic method. 4) However, it
is difficult to obtain &.ot (zo) in the neighbourhood of a touching configuration where there
appears a change in charge distribution whichcomes from difference in the charge-to-mass
ratio between the parent nucleus and its fragments. Having obtained no charge distrbution in
the touching region, we approximate the barrier&.ot (zo) by&.ot (zo) = ~ { I-tanh (Zod Zt ) } E~~l (zo)+ ~ { 1+ tanh ( ZodZt ) }

E~~{ (zo)Here we introduced two weighting factors of aWoods-Saxon form with a diffuseness parameterd of (1/2) (1-tanh((zo-zt)ld)) and (1/2)(1+
tanh ((zo - Zt) I d)) , which are nearly equal to one
and zero for Zo <: Zt and zero and one for Zo ~ Zt ,respectively. We put d=O.5 fm for the present
calculation. Zt is Zo when the two fragments aretouching at the surfaces. The energy E~~l (zo) is
the microscopic-macroscopic energy in the configuration of the parent nucleus, and E~~l (zo) in
the configuration of two fragments. The key
quantity to correctly predict the branching ratios
in a tunneling calculation is the release energy
Q in disintegration. The Q-value estimatedfrom the observed ground state masses was used
in Refs. 1 and 3. while it is automatically calculated in the present calculation. Therefore, it isvery important to confirm if our microscopic
shell correction energy L1Eshell (CAL) can reproduce the experimental shell correction energy
L1Eshell (EXP) , i.e., the energy difference between
the observed mass excess and calculated
macroscopic energy. We used a set of parmeters
given on the first row in the Table 1 of Moller,
et al. 4 ) Since their parameter set was adjusted
to reproduce the observed ground state mass ofmore than one thousand nuclei fairly well, we
confirmed good fitting of L1Esheil (CAL) to
L1Eshell (EXP) in the configuration of well-separated fragments. For examples, L1Eshell ( CAL)26

S. Yamaji, et at.

= - 13.0 MeV, 41&hell (EXP) = - 12.4 MeV
for 12C emission, 41&hell ( CAL) = - 10. 8 MeV,
41&hell ( EXP) = - 10. 0 MeV for 180 emission,
if we normalize 41&hell ( CAL) = 41&hell ( EXP )= -15.8 MeV for 14C emission. For a decay,
41&hell ( CAL) = - 2. 0 MeV > 41&hell ( EXP) =- 6.0 Me V. This discrepancy mainly resultsfrom the a-cluster correlation which was not
explicitly taken into account.
The WKB expression for penetrability wasevaluated for a particle and heavy cluster emissions. The effective mass in the disintegration
degree of freedom was taken simply as a reduced
mass of the fragments.
The branching ratio R (X/14C) of an X particle
to 14C emission from 222Ra is given in Table 1.
The resulting ratio R (ajI 4C) ------8 X 108 was foundto be in good agreement with the observed ratioof Price, et at. 2) (3 X 109 ) . The inclusion of thea-correlation energy which makes 41&hell (CAL)
small approaches the calculated ratio R (a / l4 C)
closer to the observed ratio.
The estimated ratio R (12CjI4C) seems to suggest the reason why no 12C emission has beenmeasured. 2) In order to see this more precisely,
we show a potential barrier &.ot and a shellcorrection energy ~&hell' The solid and dashedlines correspond to 14C and 12C emissions, respecTable 1. Branching ratio R (X/ 14C) of 222Ra decay.
R (X/ l4 C)
R (X/l4C)
X
X
4He

9 x 108180

5 X 10- 10

lOBe

2 x 10- 5

22Ne

3 x 10- 22

JOC

3 X 10- 31

28Mg

6 x 10- 36

12C

2 X 10- 2

38S

7 X 10- 43

14C

1

48Ca

2 x 10- 49

16C

6 X 10- 10

56Cr

1 x 10- 58

160

3 X 10- 9

68Ni

1 x 10- 53

20I_ _ 14C+20ilpb____ 12C + 2lOPb

I

I

I

E tot

15

/

I
I
I

I

/

5

,/'

/

I

I

I

I

I

\

,,
\

\

\

\
'\

'\

....' , /"

'\

,

'\

,

"
Zo (fm )

~ -10
""J

-15

Fig. 2. Potential barrier &.ot and shell correctionenergy LlEshell as a function of deformation Zo for 14C
and 12C emissions.

tively. The gain of the release energy or L1Eshellfor 14C compared to 12C reduces the ratio R (12C
/14C). It must also be noticed that 41Eshell isstrongly deformation-dependent in the configuration of a parent nucleus, as seen from the lower
curves in Fig. 2.
References
1) A. Sandulescu, et at.: Sov. ]. Part. Nucl., 11, 528(980); D.N. Poenaru, et at.: ]. Phys. G, 10, L183
(1984).
2) H.J. Rose and G.A. Jones: Nature (London) ,307, 245(1984); S. Gale, et at.: Phys. Rev. Lett., 53, 759 (1984);
P.B. Price, et at.: Phys. Rev. Lett., 54, 297 (1985).
3) Y.]. Shi and W.J. Swiatecki: Phys. Rev. Lett. , 54, 300(1985).
4) P. Moller and ].R. Nix: Nucl. Phys., A361, 11 (1981).

27
RIKEN Accel. Prog. Rep. 22 (1988)

111-1-11.

Master Equations in the Microscopic Theory of
Nuclear Collective Dynamics

F. Sakata, * M. Matsuo, T. Marumori, ** and Y. 2huo***dissipative collective motion, coupled master equations,time-dependent Hartree-Fock, selfconsistent collective
coordinate method.

In such an isolated finite many-body quanta I
system as the nucleus in which the self-consistentmean field is realized, collective modes of motion(associated with time evolution of the mean
field) are highly involved with single-nucleon
motion in a strongly selfconsistent way. A microscopic theoryl) to describe such collective
motions has been developed, which employs thetime-dependent Hartree-Fock (TDHF) approximation.
We formulate a general framework on thebasis of the microscopic theory so that we can
not only describe conserved large-amplitude collective motions as well as dissipative ones, butalso investigate the mechanism of the transition
between the two types of collective motion.
The collective motions is displayed as adynamical evolution of the ensemble of TDHF
state vectors and is also represented as a bundleof the trajectories in a phase space. We introduce
a dynamical canonical coordinate (DCC) system:
an optimal set of collective (relevant) variables(17,17*) and non-collective (irrelevant) ones (~a,~ a *), the former of which represents a bulk
feature (mean trajectory) of the bundle while thelatter the fluctuation around the mean trajectory.
The DCC system is determined in an extended
formulation of the selfconsistent collective coordinate method. 2) Thus a basic equation for thecollective motions is given by the Liouville equation

where P (1,1,1,1* ; ~, ~* ; t) represents the distribution of the bundle of trajectories. The
Hamiltonian corresponding to the Liouvillian* Institute for Nuclear Study, University of Tokyo.
** Institute of Physics, University of Tsukuba.
*** Institute of Atomic Energy, Beijing, China.

y* = i{H, * }P.B.

(2)

has generally the following form
H = Hcoll (1,1,1,1*) + HcouPI (1,1,1,1* , ~, ~*)(3)

We apply the time-dependent projection operator method of Willis and Picard 3 } to the Liouvilleequation. This makes it possible to treat not only
time evolution of a reduced distridution function
P'7 (1,1 , 1,1 * ; t) = Tr.; P (1,1 , 17 * ; ~, ~* ; t) for the relevant variables but also that of the reduced
distribution function P';(~,~*; t) =Tr'7P(1,1 , 1,1*;~ , ~* ; t) for the irrelevant variables, without
introducing any statistical hypothesis even forthe latter. The Liouville equation thus leads toP'7(t) = - i5/coIlP.,(t) -iY'7(t)p'7(t)- f :- lo drTr.;ICt. (t) g(t, t-,r)• .Yt. (t -'r) P'7 (t -,r) P.; (t -,r)P.;(t) = -i5Z!;(t)p.;(t)- f~-4,drTr'72"t.(t)g(t,t-r)• ftft.(t-T)P'7(t-T)P.;(t-T)(4)

where Y coli is a Liouvillian for the collective
Hamiltonian H coll . Coupling Liouvillians Y'7 (t),~.; (t) and I£ t. (t) correspond to parts of thecoupling Hamiltonian HCOUPI,
H'7(t) =Tr.;HcoUPIP.;(t) = <HCOUPl >';,tH.; (t) =Tr '7HCQUPIP'7 (t) = <HCOUPl >1/,tHt. (t) =HcOUPl- <HCOUPl >'7,t- <HcOUPl >';,t+ Tr'7 Tr .; P'7(t)P.;(t) HCOUPI

(5)
(6)

(7)

the first two of which represent the emsembleaveraged effects of the coupling while the last
the fluctuation around the average.
The coupled master equations (4) are generaland equivalent to the Liouville equation (1). It
also allows us to introduce approximation
schemes, e.g., the purturbation with respect tothe coupling Hamiltonian HcoupI. or the moresofisticated perturbation with respect to the fluc-

28

F. Sakata, et al.

tuation of the coupling Hfl where the mean effectof the coupling Ht/ and H4 are taken into accountin the zero-th order. Thus the coupled masterequations (4) provide us with a basis for description of the dissipative behavior of the largeamplitude nuclear collective motions and forinvestigating their microscopic origins.
References
1) T. Marumori, T. Maskawa, F. Sakata, T. Une, and Y.

Hashimoto: Nuclear Collective Dynamics (The 1982
International Summer School of Nuclear Physics,
Brasov, Romanis), World Scientific, p. 1 (1983); T.
Marumori and F. Sakata: Particles and Nuclei,
World Scientific, p. 207 (1986).
2) T. Marumori, T. Maskawa, F. Sakata, and A. Kuri ·yama: Prog. Theor. Phys., 64, 1294 (1980).
3) c.R. Willis and R.H. Picard: Phys. Rev. A, 9, 1343
(1974).

29
RIKEN Accel. Prog. Rep. 22 (1988)

111-1-12.

Dissipative Collective Motion in the Non-Linear Dynamics of the
Nuclear Time-Dependent Hartree-Fock Theory
M. Matsuo and F. Sakata*dissipative collective motion, time-dependent Hartree- J( Fock theory, Liouville equation, fluctuation.

The time-dependent Hartree-Fock (TDHF)
theory for microscopic description of nuclear
collective motions incorporates well the nonlinear nature that emerges from the strong selfconsistency between a large amplitude meanfield motion and single-nucleonic motions. We
formulated a general theoretical framework I)
based on the TDHF theory to describe the collective motions which shows dissipation. In thistheory the dissipation is expressed as diffusing
behavior associated with the bundle of the trajectories, and this arises from the non-linear timeevolution of the TDHF trajectory.
In order to illustrate that the dissipation due tothe non-linearity manifests itself, we perform
numerical simulations for the three-level Lipkinmodel which is a simplification of the nucleus. 2 •3 )The TDHF dynamics for the model system is
described by only a pair of the relevant (collecitve) coordinate ql and momentum PI andanother pair of the irrelevant (non-collective)
coordinate q2 and momentum P2. We numericallysolve the Liouville equation for the distributionfunction p (qlJ PIJ q2J P2; t) which represents theevolution of the bundle of the TDHF trajectory.
The distribution function at the initial time is set
up so that it associates with high collectivity: thereduced distribution function P17 (qlJ PI; t = 0) for
the relevant variables is stationary with respect
to a collective Hamiltonian (s17 U=O) OCO(HcOll (qlJPI) - ECOll ) ) and the reduced irrelevant distribution P~(q2J pz; t=O) has Gaussian distribution.
The dynamical behavior varies depending on theinitial collective energy ECOll 'It is indicated what kinds of the collective
motions manifest in the model in Fig. 1, whichshows typical three examples of the resultant
reduced distribution functions P17 (qlJ PI; t) andP~(q2J P2; t) after several periods of the collective
motion. In the calculation shown in Fig. 1 (a) , the*Institute for Nuclear Study, University of Tokyo.

collectivity (defined as focusing of the distribution) persists well during the time evolution.
This situation, which we call the collective one,
represents the conserved collective motion. On
the other hand, the collectivity in Fig. 1 (c) isalmost lost, which represents that no collective
motion is expected in this situation. This situation can be called the stochastic one. Figure 1 (b)shows the intermediate behavior between these
two extremes; the collective motion as a bulk
property of the system remains while the collectivity is partially lost. This is just the situation which we can identify as a dissipative collec42.... 0

0...

-2

(

//'

\

i

"'---_

.'

2

"

\

\

4

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

/

NO
0...

-2

../ /

-4

-4

4

4

2

2
J!O,~

NO

~

0...

-2

-2

-4

-4

4

(b) Eco ll=5

4

4

2

2

.... 0

-4

NO

0...

0...

-2

-2

-4

-4
-4

4
-4
(c) Ecoll=1

o
Q2

4

30

M. Matsuo, et al.

tive motion.
The coupled master equations which have been
proposed in our previous work l ) give an classification of the coupling between the relevant andthe irrelevant degrees of freedom: the mean partof the coupling and the fluctuation part which is
not taken into account by an ensemble averageover the reduced distribution function. By calculating the distribution function with neglecting
the fluctuation part of coupling and comparing itwith the Liouville solution, we found that thedissipative behavior shown in Fig. 1 (b) is causedby the fluctuation part of the coupling, which has
not been emphasized so far.
References
1) F. Sakata, M. Matsuo, T . Marumori and Y. Zhuo:
This Report, p. 27.
2) S. Y. Li, A. Klein and R. M. Dreizler: ]. Math. Phys.,
11, 975 (1970).
3) K. Muramatsu, F. Sakata, Y. Yamamoto, and T.
Marumori: Prog. Theor. Phys., 73, 380 (1987).

31
RIKEN Accel. Prog. Rep. 22 (1988)

111·1·13.

Microscopic Derivation of Transport Equation in theTime-Dependent Hartree-F ock Theory

M. Matsuo, F. Sakata, * T. Marumori, ** and Y. Zhuo***dissipative collective motion, Fokker-Planck transport[ equation, time-dependent Hartree-Fock theory.

We have developed, on the basis of the timedependent Hartree-Fock (TDHF) description of
nuclear many-body dynamics, a general theoretical framework for the large-amplitude collective
motions that shows dissipation. I) This theory
provides us with coupled master equations bothfor the time-evolution of the collective degrees of
freedom and for that of the non-collective ones,
and the master equations are formally equivallent to the Liouville equation. On the other hand,
many phenomenological theories have describedthe dissipative collective motions with use oftransport equations like the Fokker-Planck
equation. We make a connection which links
between the microscopic TDHF equation and thephenomenological Fokker-Planck equation.
In the master equations, the coupling
HCOUPI ( 17, 17 *, ~, ~*) between the relevant(collective) variables (17, 17*) and the irrelevant(non-collective) ones (~, ~*) are decomposed
into two parts: the mean parts
H,,(t) ==Tr~HcoUPIP~(t) = < HCOUPl > ~ . t
H~(t) ==Tr"HcoUPIP,,(t) = <HCOUPl >". t

(1)
(2)

which are the emsemble average over the distribution functions P,,(17,17*; t) and p~(~,~*; t) of
the partial system, and the fluctuation partHt.(t) ==HCOUPl- < HcoUPl > " .t - < HcoUPl > ~ . t+Tr 1J Tr~p" (t) p~(t) HcOUPI(3)

Since trye numerical simulations of the Liouvilleequation for a simply solvable model haverevealed that the fluctuation part of the couplingcauses the dissipation of the collective motion ina certain situation,2) we put emphasis on theeffects of the fluctuation part in this analysis.
Perturbation with respect to the fluctuation
part up to the second order approximates the* Institute for Nuclear Study, University of Tokyo.
** Institute of Physics, University of Tsukuba.
*** Institute of Atomic Energy, Beijing, China.

1master equations into the following form.
p1J (t) = - i£COllP" (t) - i£1J (t) p" (t)+ f_TTd-r[ -~Xab(t, t--r) { A~, (A~(t, .
t - -r) - <A~> ". t-.,J /5" (t , t - -r) }P.B.

+ ~yrab (t, t- -r) {A~, {A~(t, t- r) ,ab/5,,(t, t- -r) }P.B,}P.B.J
P~ (t) = - i 9'~ (t) P~ (t)(4a)+ (T d-r[ -~Xab(t,t--r) { B~, Cfj~(t,) 0

abt- -r) - < B~> ~ . t - . . ) /5~(t, t- -r) }P.B.

+ ~ 1jab ( t , t - -r) {B ~, {13 ~ (t , t - -r) ,ab/5q(t, t- -r) }P.B,}P.B.J(4b)where the notation for the coupling Hamiltonian
HCOUPI (17,17* ,~, ~*) =~A~(17, 17*) B~(~, ~*)a(5)

is used. The Liouvillians ~ 7J and 1£q correspondto the mean couplings (1) and (2).
Xab (t, t - -r) == - (J (-r) Tr~{Bt13~(t, t- -r) }• /5q(t,t--r)and+ab (t, t- -r) == (J (-r) TrqB~(13Ht, t--r)(6)- < B~> q . t - . . )/5q(t,t--r)(7)

correspond to the response and correlation functions in the linear response theory for quasiequilibrium statistical mechanics.
Xab (t, t- -r) == -Tr ,,{A~,A~(t, t- -r) }• /5,,(t,t--r)(8)

1j ab(t,t--r) ==Tr"A~(A~(t,t--r)- <A~> ". t- ... ) /5" (t, t - -r)(9)are counterparts for the collective variables.
Quantities with tilders represent the interaction
picture, for example

32

M. Matsuo, et at.
p,,(t,t--r)=9,,(t, t--r)p,,(t--r)(10)

The reduced master equations can be solved
analytically under the assumption that the timescale of the relevant (collective) motion -rrel ismuch larger than that of the irrelevant (noncollective) motion -rjrrel. This assumption
enables us to solve the master equation (4b) for
the irrelevant degrees of freedom with the use ofa kind of the adiabatic expansion and leads tothe solution for the N-th moment <e r N » ~ ~.' of theirrelevant variables (~, ~*).
(11)

Here the factor e [N) arises from the effect of thefluctuation coupling represented by the last two
terms of Eq. (4b) and it is determined by a selfconsistency condition. When e [ N ) takes positive
value, the excitation of the irrelevant modes
increases as the time evolves, and correspondingly the energy dissipates into the irrelevant
modes from the relevant degrees of freedom.
In this situation, we can introduce the Markoff
approximation for the master equation (4a) for
the relevant degrees of freedom. Thus we obtainp,,(t) ={H~Oll(t) ,p,,(t) }P.B.

+ ~M¥), :t <A~ (t) >". dAJ (t),kIp" (t) }P.B.

- n=O.l"kl~ ~ M ~+ (t){A k (t) (A7(1I) (t)"',,- <AJ<n) (t)>".,) p" (t) }P.B.

+ ~ ~ N ¥1+ (t ){ A J(t) ,'1=0 .1k I{ AJ<n) (t) ,p" (t) } P.B. } P.B.
A 7(n) (t) ="(12)(~) II A7 (t, t--r) I
a-r"

(13)
1' = 0which has formally the same structure as the
Fokker-Planck transport equation. Since the
Poisson bracket { , }P.B. induces the derivativewith respect to the relevant variables Cr;, 17*) ,the first three terms in the right-hand side represent the drift terms and the last term the diffusion tern1. The transport coeffecients are givenby the n-th moments of the response and correlation functions
(14)
(11)

N 11 =

f oo d-r !-rn-1Jf '1 I (t, t - -r)

(I 5)

n.
which can be evaluated by means of the same
technique as for the irrelevant master equation(4b) .
-00

References
1) F. Sakata, M. Matsuo, T. Marumori, and Y. Zhuo:
This Report, p. 27.
2) M. Matsuo and F. Sakata: This report, p. 29.

33
RIKEN Accel. Prog. Rep. 22 (1988)

111-1-14.

Average Partial Level Density Including the Effectof Residual Interaction
K. Sa to and S. Yoshida

Level density, Precompound reaction, Realistic J( one-body spectrum, Random matrix.

To evaluate the cross section for precompoundreactions, the level density Pm(E) with fixed
exciton number m is necessary. Its importantrole in the theory of precompound reactions has
recently been stressed. 1) Thus, the calculation of
the level density in terms of single-particle
energies and of two-body interaction matrix
elements in a large shell model space is highly
necessary. For the calculation, however, thebasis must be made sufficiently large and a standard matrix diagonalization method is not feasible.
Therefore, we adopt the precompound theory 2)
based on the Gaussian Distributed Ensemble(GDE) , which is the extended ensemble of GOE
so as to violate orthogonal invariance and to
adopt a chaining hypothesis. The theory gives us
a framework to obtain the level density Pm fromthe solution of saddle point equations which takethe second moments of GDE as an input. In the
recent papers 3• 4) we proposed an approximate
method of calculating the second moments whichcharacterize the GDE in terms of two-body interaction matrix elements. Taking the second
moments as an input, we calculated the level
density Pm (E) and the total level density P (E) .
The results showed that the residual interaction
greatly enhances the level density especially in a
low energy region and may improve the agreement with experimental data at thermal neutron
resonances. The theory assumed, however,that the one-body part of the Hamiltonian has adegenerate spectrum in every subspace m, which
is not generally realistic.
We have recently proposed a way of including
the realistic one-body spectrumS) in the calculation of level densities. In the present report weoutline the result of such an extension andnumerical calculation.
Using the method of generating function and
Grassmann integral given in Ref. 2 (a slight
modification is necessary to include the realistic

one-body spectrum), we obtain the following
saddle point equation for '(m:'(m = Am 2 N m-1 ~ (E + io- emJ1 - '(m)-l+ n(-=I=-m)~ ~n2 Vm.
N:n XNn-1~(E+iov(1)(m=2,4,"')

The average partial level density Pm is given by

Pm=-lIm~ (E+io-e mJ1 -'(m)-lJ.l7(where e mJ1 is the eigenvalue for the one-body
Hamiltonian in class m, and N m is the number ofsta tes in class m. Strength parameters Am 2 and
208Pb (Np'90, Nh'761

GGS I res. tnl.

::: 1020
I

>
~
>-

t;

III

Z

ILl

o

...J 10

10

ILl

>
ILl
...J

...J

«

~

:
10 0 LLL----L-L-....Il---L-:I:':-o.l..l...----'..l------'~--'--'----'---'----!30·

E (MeV)

Fig .1. Level densities with fixed exciton number mfor 2osPb.
Z08 Pb

~

I

..

>

(Np'90 I Nh'76)

GGS I res. Int.
10 20

d\generOle~__ -l.-~ ~-

>-

t::;

If)

Z

w
0
-l
W

.1----'"

10 10

/

,,--"

/

j/

>
W

("

-l
-l

«

5r 10

0

nl
0

10

20

E (MeV)

Fig. 2.

The total level density for 2osPb.

30

34

K. Sato, et al.

Amn 2 (m *- n) are given by second moments Mmnfrom the relations Am 2 =Nmx Mmn and Amn 2 =I NmNn X Mmn. Comparing Eq.1 with that for thedegenerate spectrum case of Refs. 2-4, we seethat the present extension requires to replace thepropagator (E - h m- Am) -1 in the degeneratecase by N m-1 X (E + io- emfl- 'tm) -1.
We performed numerical calculation of level
densities Pm (E), which are shown by solid,
dashed, and dot-dashed curves in Fig .1. As fora realistic one-body spectrum, we used the onebody level density which was given by
Oblozinsky and Kalbach, and for second
moments the same as Ref. 3 taking GGS I residual interaction. Figure 2 shows the total level
density P (E) = ~Pm (E). The solid curve(deformed) was calculated by using realistic
one-body spectrum for em)l, while the dashedcurve (degenerate) uses a degenerate one for em)l.

Comparing these two curves, we easily see thata valley, which is not physically observed, does
not appear when we include the realistic oneExcept for such a drastic
body spectrum.
change, the overall behavior of the level density
remains almost unchanged.
In summary, the previous calculation of thelevel density is improved by including the realistic one-body spectrum with a fixed exciton number m.
References
1) H. Nishioka, H.A. Weidenmtiller, and S. Yoshida:Phys. Lett. B, 203, 1 (1988).
2) H. Nishioka, J.J.M. Verbaarschot, H.A. Weidenmtiller and S. Yoshida: Ann. Phys., 172, 67 (1986).
3) K. Sato and S. Yoshida: Z Phys. A, 327,421 (1987).
4) K. Sato and S. Yoshida: Z Phys. A, 330, 265 (1988).
5) K. Sato andS. Yoshida: to be published in Z Phys. A.

35

RIKEN Accel. Prog. Rep. 22 (1988)

111-2. Atomic and Solid-State Physics
1.

Cross Sections for Radiative Electron Capture Calculated bya Relativistic Impulse Approximation-Formulation
K. Hino and T. Watanabe

The relativistic effect in radiative electron
capture (REC) was firstly observed by Spindler,
et al.l) in the bombardments of a target with alight projectile ion. Their observation shows thatthe radiation pattern of K-REC (REC into a
K-shell orbit of a projectile ion) is of a forwardbackward symmetry, i.e., the angular distribution of photon emission has a sin 2 ()L -dependencewith respect to an angle ()L measured from theincident direction in the laboratory frame. This
result is qualitatively understood as the cancellation of the retardation effect of emitted photons
by the aberration effect of the emission angle,
i.e., by the Lorentz-transformation effect fromthe moving-frame into the laboratory frame.
Anholt, et al. 2 ) also observed sin 2 ()L -dependence
in the case where a Xe 5 4+ ion collides with a Be
atom at 197 MeV l u. Hino and Watanabe 3 ) theoretically confirmed such behavior of the REC
photon angular distributions by employing therelativistic strong-potential Born (SPB) approximation and showed that the angular distributionof photons is slightly enhanced for the backward
direction in the case of a 422 MeV lu U 92 + colliding on a Be atom because of a strong Coulomb
distortion between the ion and the active electron. Furthermore, in contrast to K-REC, L-REC(REC into a projectile L-shell orbit) is asymmetric because the photon retardation corrections do not cancell the aberration effects.4)
Aside from the photon angular distributions,the relativistic effects of the REC are revealed
from the observations of the linear polarization
correlations (linear polarization dependence onemission angle in the laboratory frame) of emitted photons as we11. 4 ) A polarization vector of aphoton induced by collisions with non-relativistic
relative velocity always lies on the scattering
plane constructed by vectors of the photon
momentum and the incident velocity. This polarization vector gets to turn its direction from on
the scattering plane to the plane perpendicular to

it with the increase of velocity. Furthermore, thepolarization correlation of the photon shows aninversion of its sign at a certain emission angle in
the relativistic energy region. This is called a"crossover" feature. According to the Born
calculation,4) this feature appears in the forward
direction relative to 90° when vi c> 0.8 with v
and c being the relative velocity and the velocity
of light, respectively.
An internal conversion process, hereafter, thiseffect is referred to as the abbreviation of ICP.
ICP is herein used to mean the process depictedin the second graph of Fig. 1. The first Feynman
diagram shows the conventional REC process.
The second diagram indicates the contribution of
an intermediate positron. At the first stage, apair of an electron and a virtual positron iscreated with an emission of a real photon, thenthe positron propagates in the intermediate state,
and finally a pair of this positron and an initial
electron is annihilated into a virtual photon
associated with the Coulomb interaction between
an active electron and a projectile ion. This

(1)

(2)

Fig. 1. Feynman diagrams for the relativistic radiativeelectron capture process. P, T, e-, and e+ stand for a
projectile ion, a target nucleus, an electron, and apositron, respectively. A black bold block represents a
Coulomb interaction.

36

K. Hino, et at.

effect is expected to become very important with
the increase in Z p. This is because ICP may beinterpreted as follows: The strong electric fields
due to the existence of a heavy projectile will
induce a vacuum polarization cloud around itself. But the time-variation of the projectile will
partially break up the virtual pairs in collisions
into the real e+e- pairs. S) The electron is converted to a final electron bound on a projectile and,on the other hand, the positron is annihilatedwith an initial electron. The relativistic effects of
K-REC X-ray angular distribution in the case ofhigh Z p should not be separated from the influences of ICP.
Here we are going to investigate the K -REC
photon angular distributions, the K-REC total
cross sections, and linear polarization correlations of emitted photons up to the ultrarelativistic incident energy region by virtue ofthe relativistic impulse approximation (RIA) including the whole relativistic effects with ICP.
We refer to a reason why the impulse approximation (lA), not the SPB approximation 6 ) used in
our paper previously, is adopted in the present
calculations.
The difference between SPB and IA is thepresence of the Coulomb off-shell factor in theformer (or latter). According to Gorriz, et at.,7)
the non-relativistic REC cross section calculatedby the SPB approximation is almost double ofthat by IA 8) because of the presence of this offshell factor. Following the statements by
Jakubassa-Amundsen, et at.,9) the photon angular distribution of REC should be smoothly connected with that of the (two -body) radiative
recombination process (RRP) at the on-shell
limit, i.e., when the binding energy of a target
atom becomes zero. The result of the original
SPB approximation does not satisfy this requirements. Jakubassa-Amundsen, et at. settled thisdifficulty temporarily by renormalizing the SPB
wave function, in other word, by dividing it by afactor ascribable to this discontinuity between
REC and RRP at the on-shell limit so as tosatisfy the requirement of the smooth connection.
Further, it is found that the discontinuity of REC
and RRP is eliminated by incorporating theeffect of the asymptotic Coulomb tail with the
SPB wave function in accordance with Dollard's
idea,IO) and the resultant REC cross section
becomes in agreement with that by lAY) The
same statement is applicable to the cross sectionof the relativistic REC. Therefore, we do not
employ the SPB approximation in the present
article.
We assume the collision system consists of a

Table 1. Rations of K·REC total cross sections calcu·
lated by using the RIA with including effects of ICP to
those by RIA without ICP.
Incident velocity I v I

Collision
system

0.70

0.80

0.90

0.99

Ne1O+-Be
Xe 5 4+-Be
U 92 +-Be

1.006
1.21
1.82

1.007
1.22
1.90

1.008
1. 25
2.02

1.009
1.32
2.40

projectile ion (P) with the electric charge Z pe, atarget nucleus (T) with Z Te, and an active electron (e) with - e for simplicity. The transiton
matrix of the REC is given by
TREC=-e<1/I'f<-) 1 Y4ypA*p 11/1'1<+»(1)
by using notations of Dirac's y matrices thaty = - if3a and Y4 = f3 with a and f3 being the aand f3 matrices with respect to an electron. The
wave function A *p of an emitted photon is provided as follows:
A *p = (2n )-3/2 (2w ) - 1 / 2e~e - iH R +( MI'I M l1i, +( MTI M ) rTl(2)
where k, w, and e~ are the momentum, theenergy, and the polarization vector of an emitted
photon, respectively, R is the position vector of
the center of mass of the collisions system, and rp
and rT are the electronic position vector measured from P and T, respectively. Moreover,masses of P, T, and e are defined as M p , M T , andm, respectively, the total mass of the system aregiven by M = Mp + MT + m. The final wave function 1/I'f<-) is provided by the framework of therelativistic impulse approximation. Here we consider the case of extremely asymmetric collision(i.e., Z p ~ MT ), the initial total wave function
1/1'1<+) of Eq. 1 becomes
1/1'1<+)= (1 + Gr<+) V p ) cPl(3)
where Gr<+) is a relativistic Green function incorporating an effect of a strong potential V p
between P and e to all orders and provided byGr<+)= (E-~KNN = P,T,e

Vp +i17)-1(4)Here, KN is a relativistic free Hamiltonian of aparticle Nand n an infinitesimal real positive
value. 4>1 denotes the initial free wave function.
In order to obtain the differential cross sectionof the REC photons, we at first calculate it in themoving frame (i.e., Pc = 0) and finally Lorentztransform it into the laboratory frame (i.e., ~ =o). The photon angular distribution in themoving frame reads=(2n)41 v l-l~J dWMWM 2

Jdq< 1 tREC 1 2 >6'(WM-WM<O)-yv-q)

(5)

37

K. Hino, et at.

where the summation is taken over all initialstates, q is the transfered momentum of theelectron in REC processes, WM(O) indicates thepeak position of the photon energy WM in themoving frame and is given by WM (0) = m ( y~T - ~p)with y= (1- 1 V 12) -1/2, ~p = [1- (Zpa')2J 1/2, and~T = [1 - (STa') 2J 1/2 with ST the optimized ST the
optimized s-exponent of an active electron. The
summation is taken with respect to sT-values,£.e., initial states of bound (target) electrons
participating in REC. Here ~ is defined as anemission angle of a photon in the moving frame,and 12 M is a solid angle associated with this. The
last term in the energy-conserving o-function
represents the Doppler broadening effect of the
REC photon spectrum. Moreover, tREC and< t REC2 > have been
TREC = t REC Q<3) (K1 + ~ - K r - k)(6)and
< 1 tREC 12> =8- 1 ~ 1 tREC 12(7)helicities

where we have taken the average with respect tothe initial helicities and the summation withrespect to the final ones of all three particles, P,
T, and e.
Utilizing the Lorentz transformations:sin~ = y-IsineL / (1- 1 v 1 coseL )cos~ = (coseL - 1 vi) / (1- 1 v 1 coseL ) (8)we get the photon angular distribution in thelaboratory frame from moving frame expression:(da-/ d12 L)=(1-v 2)(1-1 vi cosBL)-2(da-/dfJ M )(9)References
1) E. Spindler, H.-D. Betz, and F. Bell: Phys. Rev. Lett.,

42, 832 (1979).
2) R. Anholt, S.A. Andriamonje, E. Morenzoni, Ch.
Stoller, ].D. Molitoris, W.E. Meyerhof, H. Bowman,].-S. Xu, 2.-2. Xu, ].0. Rasmussen, and D.H.H. Hoffmann: Phys. Rev. Lett., 53, 234 (1984).
3) K. Hino and T . Watanabe: Phys. Rev. A, 36, 581(1987).
4) K. Hino and T. Watanabe: Phys. Rev. A, 36, 5862
(1987).

5) For instance, G. Soff, ]. Reinhardt, B. MUller, and W.
Greiner: Phys. Rev. Lett., 38, 592 (1977); W. Greiner,
B. MUller, and]. Rafelski: Quantum Electrodynamics
of Strong Fields, Springer-Verlarg, Heidelberg, p. 366(1985).

6) ]. H. Macek and R. Shakeshaft: Phys. Rev. A, 22,
1441 (1980); ]. Macek and S. Alston: 26, 250 (1982);
S. Alston: 27, 2342 (1983).
7) M. Gorriz, ].S. Briggs, and S. Alston: ]. Phys. B, 16,
L665 (1983).

8) M. Kleber and D.H. J akubassa: Nucl. Phys., A252 ,
152 (1975).

9) D.H. Jakubassa-Amundsen, R. HappIer, and H.-D.
Betz: ]. Phys. B, 17, 3943 (1984); D.H. JakubassaAmundsen: 20 , 325 (1987).
10) J.D. Dollard:]. Math. Phys. , 5, 729 (1964).
11) K. Hino and T . Watanabe: Phys. Rev. A, 39,3373.

38

RIKEN Accel. Prog. Rep. 22 (1988)

111-2-2. Cross Sections for Radiative Electron Capture Calculated bya Relativistic Impulse Approximation-Total and Differential
Cross Sections and Linear Polarization
K. Hino and T. Watanabe

The total cross sections for radiative electron
capture have been calculated by using relativistic impulse approximation (RIA).l) They include
all of the relativistic effects explained in theprevious report: the relativistic velocity effect,
the high Zp-effect (projectile charge effect), thespin-orbit coupling, and the internal conversion
process of e+e- pair creation and annihilation(ICP) effect, in particular, paying an attention to
the last new effect. The K-REC (radiative electron capture into a K-shell orbit of the projectileion) cross sections for the collision systems ofXe 5 4+-Be are shown in Fig. 1, in comparison withexperiments. 2 ) Figure 1 contains two theoreticalcurves: one is the result by RIA with considera tion of Iep, i.e., in accordance with both graphsof Fig. 1 of the previous report,l) and the other by
RIA irrespective of the ICP effect, i.e., withconsidering only the first diagram of Fig. 1 ofRef. 1. The differences between two curves indicate the magnitudes of the ICP effect to K-REC.
In Table 1, we show the effect of ICP withrespect to the electric charges of projectiles aswell as velocities.
ICP has small effects on the cross section of
the Ne 10 +-Be system over all velocity regions. In
contrast, the U 9 2+-Be system is much influenced
with ICP, above all, at high impact velocities. At
the velocity of 0.99, this effect gives no less than
2.4 times greater contributions than the results
without consideration of ICP. ICP is physicallyinterpreted as an effect based on the breakup of
virtual e+e- pairs (vacuum polarization cloudaround a projectile ion induced by the presenceof its strong electric fields) into real pairs due tothe projectile motion. Thus we come to a conclusion that as long as a projectile charge is very
high, an intermediate positron has nearly thesame degree of contributions to the K-REC asthat of an associated electron. The velocitydependence of ICP is less pronounced than
expected at the outset. For relativistic heavy
ion-atom collisions not to speak of the present
REC, in general, it would be improper to neglect

..Q

0.4

0.6

0.8

VI C

Fig. 1. REC total cross sections for a Xe 5 4+ - Be collisionsystem. ICP and no ICP mean RIA calculations withand whthout including the internal conversion process,respectively. Experimental values are cited from W.E.
Meyerhof, et at. 2 )Table 1. Ratios of the K·REC total cross sections
calculated by using RIA with including effects of ICP
to those by RIA without ICP.
Collision
system
Ne1o+·Be
Xe 54 +·Be
U92 +·Be

Incident velocity I v I
0.70

O.SO

0.90

0.99

1.006

1.007

1.00S

1.009

1.21

1.22

1.25

1.32

1.S2

1.90

2.02

2.40

the effects of ICP fully from the beginning as, forexample, in the discussion of our proceeding
paper. 3 )We are somewhat concerned with simple
velocity dependence of a REC total cross section.
In the non-relativistic energy region, as indicatedby Briggs and Dettmann,4) the cross section is
proportional to I v I -5. It is difficult to deduceK. Hino, et at.

39

c
o

:;:::;:J.c

EVl'6 0.5

ro

0...

::;
OJ

c

III

45

90

135

180

OL (degrees)Fig. 2. Normalized photon angular distributions of
K-REC induced by collisions of a Ne 1o + ion on a Be
atom. c/> means the polarization angle of an emitted
photon. (e), the incident energy 0.1 GeV/ u; (A), 1
GeV /u; (.), 10 GeV l u; C.. ). 100 GeV l u, respectively.

such a simple rule from the present RIA method
because a total cross section by this method isgiven numerically and is dependent on terms
providing the ICP and the Z p effects in complicated manners. Thus, for simplicity, we evaluate
simple dependence of the velocity by applying aleast-square method to some values calculated atvelocities I v I ranging from 0.1 to 0.8 for a
N e lO +-Be, from 0.4 to 0.8 for a Xe 5 4+ - Be and from
0.6 to 0.8 for a U 92 +-Be, respectively. In thesevelocity regions, logarithmically scaled crosssections show almost straight slopes as in Fig. 1.
As a result, a semi-empirical rule is obtained as
I v I-P with p equal to 4.98, 5.19, and 5.59 forrespective collision systems. The slope of a total
cross section with respect to ultrarelativistic
velocities is steeper than that in the relativistic
velocity region considered above.
We show the normalized photon angular distributions O'N COL, 4» at polarization angles cP =0°,45°, and 90 for a N e 10 +-Be system in Fig. 2.
It is possible that the direction of a photon
polarization vector e varies in the relativistic
velocity region, while it mostly remains lying on
the scattering plane in the non-relativistic velocity region. This nature is reflected by a linear
0

-1

o

45

90

135

180

fh (degrees)Fig. 3. Linear polarization correlations for K-REC
photons induced by collisions of Ar 18 + ions on a Be
atom. (e), the incident velocity in the unit of the light
velocity 0.7; (A), 0.8; (.), 0.9; (~), 0.99, respectively.

polarization correlation function P (OL) definedby
P (OL) = [(dO'l dOL) ", = 0'
- (dO'l dOL) "' = 90"J I (dO'l dOL) unpol

where azimuthal angle cP is measured from thecollision plane around the photon propagation
direction.
In Fig. 3, we show the linear polarization
correlations of REC photons induced by collisions of Ar 18 + on a Be atom for several relativistic velocities ranging from 0.7 (376 MeV l u) to O.
99 (5.72 Ge V lu). For collisions of Ar 18 + on a Be,
it is expected that the Born prediction holds true
except for the forward and the backward angles.
Detailes will be given elsewhere. 5 )References
1) K. Hino and T. Watanabe: This Report, p. 35.
2) W.E. Meyerhof, R. Anholt, J. Eichler, H. Gould, Ch.
Munger, J. Alonse, P. Thieberger, and H.E. Wegner:
Phys. Rev. A, 32, 3291 (1985).
3) K. Hino and T. Watanabe: Phys. Rev. A, 36, 581(1987).
4) J.S. Briggs and K. Dettmann: Phys. Rev. Lett., 33, 1123
(1974).
5) K. Hino and T. Watanabe: Phys. Rev. , 39, 3373 (1989).

40
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-3. Circularly Polarized X Ray Emission
Due to Radiative Electron Capture
K. Hino and T. Watanabe

We showed that X rays emitted from radiativeelectron capture (REC) by projectile heavy ionsfrom a usual target, photons are lineary polarized due to the fact that the motion of electrons
is confined on the plane parallel to the collision
plane. I) In the nonrelativistic limit, the directionof the electric field vector of X rays is almost
parallel to the collision plane because of theconfinement electron's motion. When the spins of
the target electrons are polarized to a particular
direction, the X rays emitted from REC may becircularly polarized. We investigate the propertyof the X rays due to REC from a spin-polarizedtarget atom.
Let us consider the case where a projectile ion
traverses through with a velocity v and a photon
is emitted to the z direction with a wave vector
k and an angle between v and k of BL in thelaboratory frame as shown in Fig. l. The angular
distribution of the REC photon is given by
df5 (g, s, s')
dQ 'M

x

f

(27t)4 ~illitialVelectron Sl a tes

fd

GUM

w 2M

dq 1 tREe 12o(GUM-w~)-rv· q)(1)

in the moving (projectile) frame,2) where tREe is
the T -matrix of the REC process, ~ is the Stokes
parameter of a photon,3) Q M is the solid angle for
emitted photon in the moving frame, q is thetransfered momentum of the electron in REC
and sand s' are the initial and the final spi~states of the active electron, respectively. The
matrix tREe is essentially given by the interactionof charged particles with electromagnetic
fields. GUM and w~) are the photon energy and its
peak position in the moving frame, respectively.
They are given by w~)= m (Y~T - ~p) with y=(1 - 1 V 2)-1/2, ~p= [1 - (Zpa)2J1/2 and ~T=[ 1 - (sTa) 2J 1/2 with ST the optimized s-exponentof the Slater orbital for the active electron
where Zp is the projectile nuclear charg;, a is th~fine structure constant, and m is the electronmass. We use a natural unit system c = Ii = 1
unless otherwise specified.
',
The transformation from the moving frame(the origin of coordinate system is on the projec1zx

Fig. 1. A coordinate system for vectors k, v, and e. The
plane spanned by k and v is the scattering plane, andthat by k and e is the polarization plane.

tile nucleus) to the laboratory frame (the origin ison the target nucleus) is given by the Lorentz
transformation asd(J(g, s, s') l(B)2 df5(g, s, s')
(2)
dQ L

dQ M

L

l (BL ) = y-1 / (1- v coseL )(3)
where Q L is the solid angle for emitted photon in
the laboratory frame. The absolute value of thesquared T -matrix is given by
1

tREe

1

2

= (27t)-2 aGUM -1p~:) •!

X

Tr p(~) (0) Q)lPi(e) (- p) QII(4)
Here, P.(,: ) is the photon polarization tensor
defined by the Stokes parameter ~i as1(y ) _

P",t -

1

2~

a, b = l(a )Pab e"

(h)

e"

(5)

with e(i)=(e~i) , 0) for i=l, 2 and A=j.l, v and
with
P
ab

=l ( 1 + ~1 ~2 - i~3 J
2 ~i + i~3 1 - ~l

(6)

In Eq. 4, pte) (q) and pte) (q') are the initial andfinal spin densities having momentum q and q',
respectively, and Q)l and QII are the matrices forphoton emission from an initial momentum state
k to a final momentum state k' and its Hermitian
conjugate for v photon emission describe in Fig.
2. Here we do not take the internal conversion
processes of e+ e- pair creation and its annihilation into consideration in the calculation of QJ.l
and QII. In the moving frame, the peak momentum of the final spin density lies in zero momentum.
In the case of s'=O, Eq. 4 can be written in a

41

K. Hino, et ai.
0)d u,.-(i::Ci3, S,(2)2 aWM(0)7!

d lQ Mv(Koo + ~3 ~ Si K 3J (9)i= 0

If we define a circularly polarized photon correlation function P (()L) as
df5 (~3' s, 0)
dQM(2 ) 2 aw (0)7!

v

M l ( ()L) Koo ( 1+ ~3P (OJ)

(10)

P (OL) can be written as~siK3iP({)L)=~

Fig. 2. Feynman diagrams for the relativistic radiativeelectron capture process. P, T, and e- stand for a
projectile ion, a target nucleus and an electron, respectively. A black bold block represents a Coulomb interaction.

form of

1 t REe 12(27!)2a WM(0) ~
~
V

i= 0

C

'7iSj

K i j (p, q ) (7)We consider only the case where the final state is
not polarized and we set s' =0. Taking a peaking
approximation, we havedf5(§, s,O)(27!)2a (0) ~ c .S .K .. (=0)
dQv WM . ~ '7z J
p, q
ZJ

M

z= 0

(8)

If we consider circular polarization, we can set
El = E2 = 0 and obtain

I\"OO

When we know the initial target spin state, we
can set particular values for the parameter SiCalculation of the practical process is now inprogress.
References
1) K. Hino and T. Watanabe: Phys. Rev. A, 36, 5362

(1987).
2) K. Hino and T. Watanabe: Phys. Rev. A, 39, 3373
(1989).
3) L.D. Landau and E.M. Lifshitz: The Classical Theoryof Fields, Course of Theoretical Physics, Vol. 2,
4th ed., Pergamon, London, p. 119 (1975); V.B.
Beresteskii, E.M. Lifshitz, and L.P. Pitaevskii:
Quantum Electrodynamics, Course of Theoretical
Physics, Vol. 4, 2nd ed., Pergamon, London, p. 24(1982).

42

RIKEN Accel. Prog. Rep. 22 (1988)

111-2-4. Dynamic Electron Correlation in Double Ionization
by Charged Particle Impact and Photon Impact
T. Watanabe and L. Vegh*
After the significant different measurement of
the double ionization by anti-proton bombardment on atoms from that by protons,1.2) muchattention has been attracted to the correlation
effect on the occasion of dynamical processcaused by charged particle impact, such as electron, positron, proton, anti-proton, and multicharged ions, as well as photon impact. 3 •4 ) Firstly
we will make a short discussion of this problem
and give a short review under the concept of thefirst order perturbation (Born) theory. Then weare going to refer a new method for the double
ionization. It has been recognized that the Born
cross sections for excitation and for ionization
do depend neither on the sign of projectile charge
nor on its mass, if the projectile has the same
impact velocity. It is expected to give the same
total cross section for single ionization and excitation as well in the high (but non-relativistic)velocity range regardless of projectile particles.
For atomic targets, single-ionization cross sections obtained by fast proton and anti-proton
projectiles are found to be the same. 1.2) Let us
consider the process of inelastic collision by the
impact of a charged particle with a charge Zle
and a velocity v. The cross section (O"ex or O"lon)for excitation or ionization of the atomic target
can be given by the Born approximation asO"ex. Ion

8 ~Z~e4fKm.xK-3

hV

K m 1nx I <'I/I'n I ~exp(ik·;) 1'1/1'0> 12 dK(1)jwith Kmax=m(v+vn)/Ii, Kmln=m(V+vn) / Ii, and
Vn = 12 (E - En) / Ml where m is the electron
mass, M1 the mass of projectile ion, e the electronic charge, and liK is the momentum difference before and after collisions. E is the totalenergy and En is the n-th eigenenergy. The integrand of Eq. 1 indicates that the differential
cross section is also common for various charged
projectiles if the integrand is written as a func* Institute of Nuclear Research of the Hungarian Acad·emy of Sciences, Debrecen, P.O. Box 51, H-4001,
Hungary.

tion of momentum change Ii K. However, thispoint have not been investigated yet.
The ionization by charged particles at the highenergy limit is well explained by the Born
approximation, Eq. 1. Equation 1 shows the independent characters of the cross sections on thesign of projectile charge and the mass of projectile particles in the same impact velocity in thecenter-of-mass frame (C. m.) as mentioned
above. A difference is found in the angular distribution of ejected electrons. The differential crosssection with respect to the angle of an ejected
electron is quite different between the sign aswell as the mass of projectile particles. The
difference appears as result of the interaction
between an ejected electron and a projectile
particle. It is expected reasonably from the interaction between them.
The cross section for double ionization can be
written by the Born approximation, if we extend
the method straight-forward by using an independent electron approximation, which is themethod that each electron state follows the solution of the Hartree-Fock equation in each step ofthe electronic transition. Here, we ignore theinteraction between electrons during transition.
According to the independent electron model
scheme, a double ionization process can be classified into two processes, one is single ionization
followed by shake-off transition and the other issuccessive two-step single-ionization. The shakeoff is a process of ionization due to the suddenchange of an atomic field as a result of firstionization. The scattering amplitude of the second process is considered to be proportional to
the square of a projectile charge, but is considered to decrease with the impact velocity at ahigher rate than in the shake-off process.
If we take the ratio of the cross section of
double ionization to that of single ionization, theratio should be constant at the high velocity limit
when the shake-off process is dominant. The
collection of these data indicates that the ratio
tends to be constant at the high velocity limit
regardless of projectile particles.
Besides the high-velocity limit, the cross sec-

43

T. Watanabe, et al.

tion ratio Rc is significantly different dependingon the sign of the projectile charge. This is due tothe electron-electron interactions in the target
systems. If we consider the effective potential
range of double ionization, the potential range inthe case of positively charged particle impact isreduced because of the large sum potential overthe interaction of a projectile particle and electrons, and the interactions between electrons are
reduced compared with that of interactions
between the projectile and electrons without
interactions between electrons. On the contrary,
for a negatively charged projectile, the interaction domain is expanded, if we consider theregion corresponding to the potential summed
over the interaction between the projectile andelectrons as well as the interaction between
electrons. This feature may explain that thedifference in Rc is in the case of a negative or apositive charged projectile.
If we see the ratio of the cross section of
double ionization to that of single ionization andthe ratio is found to be independent of a transition mechanism, the ratio is expected to be thesame value in photo-ionization. The ratio in
photo-ionization, Rp , is not the same value, but
the ratio is larger than that of particle ionization.
This unexpected result can be explained by following discussion. In photo-ionization, the ratio
Rp shows the direct correspondence with theshake-off factor and the agreement between
experiment and calculation is satisfactory at thepresent time. For photo-ionization, the theory
does well describe the phenomena. For charged
particle ionization, however, there are some idealization procedure of the problem in order tomake the matter possible to handle. One of thefact which needs idealization is as follows:
A target nucleus is regarded as a simple spectator.
A nucleus itself is in a free state in principle
and it can absorb energy even in a small amountduring collision.
A dominant difference between the photoncase and the particle case is the magnitude of
momentum of the initial perturber. The momentum of photon is so small that it can not movenucleus in any significant amout. On the other
hand, the momentum of incident particles cangive momentum to a nucleus. Considering thatthe momentum given by the projectile particle
can be shared by ejected electrons and thenucleus, the directions of motion of the electron
and the nucleus are considered to nearly parallel
to each other. This effect may reduce the overlap
integral in the second ionization scattering

amplitude by the shake-off process.
For the double ionization process, there havebeen several theoretical studies, which explainsome properties. Characteristic features of the
projectile sign dependence come from the difference in the effective interaction potential for thisphenomena. The potential should include not
only the interactions between a projectile andelectrons in a target, but also that between electrons in the target. The summation over respective pairs make the domain of interaction smaller for a positive charge projectile and make itlarger in a negative projectile. This is the mainprocess of double ionization by charged particles.
Let us consider the case of a projectile P
colliding with a He atom for simplicity. The 5
matrix for the double ionization can be given by
5 = exp (f~ooHCt') dt') 50(2)

where H (t) is the total Hamiltonian of the system. Usually H can be taken as the sum of anunperturbed Hamiltonian and a perturbation
Hamiltonian. The unperturbed Hamiltonian istaken the Hamiltonian under the initial condition. The electron-electron interaction term 1/ r 12
is involved in the unperturbed one. Here we
make a different choice as2
2
H. - __
li-\7 2_~\7 2_ 2 e _ 2 e
00 2 m 12m 2
r1
r2
(3)
2
2
Z 2 7 __
H6= +~+_LJ2_e
£
rpl

rp 2

r 12

Noting that f;o (r12 ) = exp (- ar1 - ar2 ) is theexact eigenfunction of Hoo with a=2. Because
Hoo is completely an independent particle
Hamiltonian and H~ includes the electronic correlation interaction term e2 r - 112 , we can see only
the difference in the effect of dynamic correlation in H~; the range of interaction H ~ differs
greatly due to the sign of projectile charge, i. e.,
for negative projectile charge (e.g. anti-proton)
the range of interaction H~ expands because of
the accumulation of same-sign Coulomb potentials and, on the other hands, for posi ti vely
charged projectiles (e.g. protons) the range
shrinks because of the cancellation between different sign Coulomb potentials. If we expand thetotal target states in terms of an atomic eigen
function, 5 matrix can be given by

5= T exp [ - i f~ooH~ Ct') dt' ]eeexp(-i;:jHt) So(4)

where H =Hoo- Ho and is now a diagonal matrix
and T is the time ordering operator. Further

44

T. Watanabe, et al.

investigation is now in progress.
References
1) L.H. Anderson, P. Hvelplund, H. Knudsen, S.P.
M~ller, K. Elsener, K.-G. Rensfelt, and E. Uggerh~j:
Phys. Rev. Lett., 57, 2147 (1986).
2) L.H. Anderson, P. Hvelplund, H. Knudsen, S.P.

M~ller, A.H. S~rensen, K. Elsener, K.-G. Rensfelt,
and E. Uggerh~j: Phys. Rev. A, 36, 3612 (1987).
3) J.H. McGuire: Lecture Note in Physics (eds. D.
Bereiny and G. Hock), Vol. 294, Springer-Verlarg,
Heidelberg, p. 432 (1988).
4) J.H. McGuire: Nucl. Instrum. Methods A, 262, 48(1987) .

45
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-5.

Calculation of Stopping Powers for Energetic Heavy Ionsin Solids and Plasmas
S. Karashima, K. Fujima, and T. Watanabe

The stopping powers for fast heavy ions incold matter and in partially ionized plasmas
were calculated over a wide range of temperature and density. A dielectric response function
method was used in the calculation.
Detailed analyses of experiments and theoriesof the energy loss of fast heavy ions in solids andgaseous media have been made. For partiallyionized media, the effects of finite temperatureon the theories must be taken into account.1 - 6)
The theoretical treatments of stopping powers
are usually based on the approximation that
stopping electrons are divided into two parts:
those bound to plasma ions and free plasma
electrons. The stopping power in ionized media
depends on the effective charge and incident
energy of projectile ions and on the dielectric
polarization of matter.
According to the Brueckner·Senbetu-Metzler(BSM) theory,5) we formulate the stopping
power based on a dielectric function method.
Charged particles passing through an ionizedmedium induce an electric field by polarizing the
medium. Consequently, the particles suffer aretarding force from the medium and lose
energy. Thus we calculate the electron stopping
powers using a polarization response calculation
with a collisional dielectric function:
E (k,w)

r.~ 2

=1

uvp

because of the discrete sum which requires information on an atomic shell structure, binding
energies, and an electron density. Matter underthe extreme conditions of density and temperature can be described by application of theThomas-Fermi (TF) statistical model. The TF
theory normally assumes an ion-sphere approximation; each nucleus is placed at the center of asphere of a radius ro = (3/411:nj) 1/3, where n[ is thetotal ion density. The electrostatic potential
V (r) inside the sphere is calculated by solving
the Poisson equation:\72V(r)=411:en(r)(2)
where n (r) is the total electron number density
including both bound and free electrons. The
electron density n (r) is determined by the formula for a finite temperature:
1 (2m)3 /2.! I (i W (WW p j2(i)+ i r i) - w/

(k a T)tl +e V(T))

(3)

kaT

2

where the Fermi-Dirac distribution function is1j(r, p)1+exp (_
1) [K-eV(r)
-Jl]
kBT
2m

(4)

The Fermi integral I (x) is defined by
I(x)j

_~

fl2

n(r) = 2 11:2-

1 +exp(x+y) 1 p2f(r, p)dp
00

0

.

1

yjdy

00

(5)

0

(1)

where k is the wave number vector and W is thefrequency. The second term in Eq. 1 represents
the contribution of plasma free electrons to thedielectric function. The effect of collisional
damping appears through the collision frequencyve, and Ve= (2Te/ m) 1/2 is the electronic thermalvelocity, where m is the electron mass. The third
term expresses the contribution of bound electrons. The frequency CUpj (i) of the i -th shellelectrons satisfies a relation W p j2 = 411:Ne 2nj m,where N is the number density of atoms, ni thedipole oscillator strength, and ria phenome·
nological damping force.
The expression for W (k, w) is complicated

The chemical potential J.l is determined by therequirement that the cell be neutral, n (r) d 3 r =Z: Z is the atomic number of matter. At zerotemperature, Eq. 3 reduces tof

3/2
2 1 (2m)3/2
n ( r) = 3' 211:2 fl2[J.l + e V (r) ](6)

The potential V ( r) is a self-consistent field, i. e.,
it must simultaneously satisfy Eqs. 2 and 3. The
dimensionless parameter x is defined by r =XbZ - 1/3 , b= (311:/4)2/3 1i2/2me 2. For the frequency
Wi, we take Ii W i =! (x) with! (x) representing
the average over the momentum distributions of
the local ionization energy of a bound electron.
In the TF approximation, ! (x) is given by

46

S. Karashima, et at.

I (x) = Ii Wo[25 4> x(x) - del>dx(x) I](7)

X= X owhere Wo= (4Z 2/ 37!) 2/3 (2me4 / li2) / Ii 2, and Xo
denotes the atom boundary corresponding to roo
The plasma contribution to the dielectric function has the plasma frequency wp :2 47!ne e 2 47!N (Z - Z b)
(8)
Wp
m
m
where 4 is the average number of bound electrons in a target ion. From these results, Eq. 1
becomes(Z - .4J

47!Ne2 {_c ( k, w ) - 1 - + . ) _ (k Ve )2
m- w (WIlle
I

3

( x.
Zx 2 eI> (x) 2 dx}-)0 w(w+ir x. ) - [I(Xo) / Ii]Z

(9)For the ionization degree in medium, we use a
Saha equation to determine the equilibrium
charge states of a target material as a function oftemperature and density. We determine theboundary condition for each ion state and calculate the number of electrons bound to the ion andfree electrons.
On the assumption that a fast ion with a velocity v moves on a straight line in the x direction,
the energy loss is given by~; =2 (~:er f dk f : dwo(w-kxv)(10)

where k 2 = k/ + k 1. 2 and Z * is the effective chargeof the projectile ion.
The numerical calculation of Eq. 10 by using
Eq. 9 is still complicated. If the projectile ion
velocity v is large enough, V» Ve , then w = kv »kve . The dielectric function can be approximatedby an expression independent of k, i. e., c (k, w)::::::c (w). In this approximation in Eq. 10, we
obtaindEdx(Z* e)

7!V2

2;:00 wdw
0

where the cutoff wave number qrn is necessary to
prevent the logarithmic divergence when q2 =k/+k/=oo. Most of the contribution to theintegral in Eq. 11 is from regions with w < qrnV.
The choice of q rn depends on the Bloch parameter r; = Z* e 2 / Ii v. This r; means the ratio of theminimum impact parameter between the classical and the quantum theory.
The collision frequency lie directly depends on
the states for weakly and strongly coupledplasmas. 7 ) A theoretical determination of lie is acomplex problem that calls for the detailed
knowledge of interparticle correlations in a coupled plasma. The phenomenological damping
force r i in c (k, w) is usually very small
compared with the binding on resonant frequencies Wi. We here take r i=0.03wi in the
numerical calculation. The effective charge dueto the semiempirical formula by NikolaevDmitriev 8 ) is used to compare with the results of
the BSM theory.
Numerical calculation of the stopping power isin progress for different temperatures and densities in matter and for various kinds of projectile ions and targets.
References
1) E. Nardi , E. Peleg, and Z. Zinamon: Phys. Fluids, 21,574 (1978).
2) T.A. Mehlhorn: ]. Appl. Phys., 52, 6522 (1981).
3) ]. Meyer-ter-Vehn and N. Metzler: MPQ, 48, 1 (1981).
4) G. Maynard and C. Deutch: Phys. Rev. A, 126, 665(1982).
5) K.A. Brueckner, L. Senbetu, and N. Metzler: Phys.
Rev. B, 25, 4377 (1982).
6) T. Peter and R. Arnold, and]. Meyer-ter- Vehn: Phys.
Rev. Lett. , 157, 1859 (1986).
7) S. !chimal: Plasma Physics, Benjamin, Tokyo, Chap.
2 (1986).
8) V.S. Nikolaev and 1.S. Dmitriev: Phys. L ett. A, 128,277 (1968).

47
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-6.

The Form Factors of the Hydrogenlike Atoms Revisited
I. Shimamura

Bethel) introduced the notion of the form factor and explained its basic significance incollision theory. It is defined as the matrix
element of ~ exp (iK • r) between a pair ofjeigenstates; K represents the momentum in unitsof h transferred from an incident particle to thetarget system in a collision with the incident
particle, and rj is the position vector of the jthparticle in the target system. To be more specific, the matrix element squared determines theprobability of the transition between the eigenstates upon momentum transfer hK within thefirst-order perturbation treatment, i.e., the firstBorn approximation. The form factors are relevant to interactions with any external agent solong as they are local, and therefore appear inmany contexts including collisions with any
charged particles or neutrons. Properties of theform factors and related quantities such as thegeneralized oscillator strengths have been a subject of continued study, both experimental andtheoretical, as summarized elsewhere. 2 )The theoretical study of the form factor naturally began with the atomic hydrogen, for which
every eigenfunction is analytically known within
the nonrelativistic point-nucleus approximation.
In particular, the transition from the ground Is
state to a discrete excited state nlm is the mostfundamental, where n is the principal quantum
number, I the azimuthal quantum number, and m
the magnetic quantum number. In fact the form
factor vanishes if m *- O. For some applications
and also for the full understanding of the results,
it is appropriate to consider a more general caseof the transition from the ground state Wooo (r; z)of a hydrogenlike atom with an effective nuclear
charge ze to a discrete state WnLO (r; z') of ahydrogenlike atom with another effective
nuclear charge z' e. Let Enl (K; z, z') denote thecorresponding form factor <W nLO (r; z') exp (iK •1r)

1 Wooo(r; z)>.

To derive an analytic expression for Enl (K; z,
one follows Massey and Mohr 3 ) using thegenerating functions of the Laguerre polynomial.
However, the crucial page, i.e., page 613, of theirpaper contains so many errors that it is difficultz')to see their precise result.
Bethe's article 4 ) in Handbuch der Physik
quotes the Massey-Mohr work, and gives anexpression for Enl (K; 1, 1) as Eq. (52.12). However, the second factor 22 (H1) of that equation
should be 22l + 3 •Furthermore, Eq. (92) of the treatise of Mott
and Massey5) is meant to be an expression forEnl (K; 1, Z) in our notation, but is also incorrect. Equations (7a) - (7e) of Shimamura 6 ) areintended to show the most general result forEnl (K; z,z'). However, z and z' should be interchanged, and the definition of x has a misprint.
In this way there is confusion even for thesimplest case of the transitions from the groundstate to discrete states. We have shown some
simple methods for proving without explicit calculations that the results in these standard articles are in error, and have derived the correct
results. We have also derived an analytic
asymptotic formula for Enl (K; z, z,) as K ~ (X).
The hydrogenic states may be defined also interms of the parabolic coordinates, the parabolic
quantum numbers being n l and n2; the principal
quantum number n and the magnetic quantum
number m are the same as in those appearing in
the treatment in terms of the spherical coordinates.
The form factor for a transition from theground state to an excited state (n, nl, n2, m = 0)
should also be studied for completeness. In principle it should be possible to derive an expression
for the form factor Enn,n2 (K; z, z') for this transition by a unitary transformation of Enl (K; z, z').
In practice, however, it is much easier to extend
the method of Landau and Lifshitz 7 ) who calculated Enn,n2(K; 1, 1). In this way we have derived
an analytic expression for Enn,n2(K; Z, z').
In many applications the sum of Enn,n2 (K; z,z,) 2 over nl - n2 at a fixed n is required. We
have also calculated this sum analytically.
Bethe4 ) and Landau and Lifshitz 7 ) give a special
case of this expression for z = z' = 1. This sum
is equivalent to the sum of 1 Enl (K; z, Z') 12 over
I at a fixed n. However, we have been unable toderive the same result from the expression for
1

1

Enl(K; Z, z').

48

1. Shimamura

Discussion of the form factor is incomplete
without mention to those eEl(K; Z, z') for thetransition to continua E. Bethel} gives a compact
expression for the sum of 1EEl(K; 1, 1) 12 over t.
This expression is more general than the counterpart for the bound spectrum in the sense thatthe analytic continuation of the former should
lead to the latter expression.
We are unaware of a convenient expression for
individual EEL (K; z, Z'). It is difficult to extend
the method of Massey and Mohr 3) to the continuum, and attempts with other methods of evaluation have been so far unsuccessful.
The foregoing exemplifies the surprisingly
incomplete knowledge of the form factors fortransitions from the ground state. The knowledge concerning transitions from an excitedstate, either discrete or continuum, is even lesssa tisfactory.
Details of this work will be reported

elsewhere. 8 )References
1) H. Bethe: Ann. Phys., 5, 325 (1930).
2) M. Inokuti: Rev. Mod. Phys., 43, 297 (1971); M. Inokuti, Y. Itikawa, and JE. Turner: Rev. Mod. Phys., 50,
23 (1978).
3) H.S.W. Massey and C.B.O. Mohr: Proc. R. Soc. London Ser. A , 132, 605 (1931).
4) H. Bethe: Handbuch der Physik (eds. H. Geiger and
K. Scheel), Vol. 24/ 1, Springer, Berlin, p.273 (1933).
5) N.F. Mott and H.S.W. Massey: The Theory ofAtomic Collisions, 3rd ed., Oxford Univ. Press,
Oxford (1965) (Japanese translation in four volumes:
Translated by K. Takayanagi, Y. Itikawa, and 1.
Shimamura, Yoshioka Shoten, Kyoto (1975-77)).
6) 1. Shimamura: ]. Phys. Soc. lPn., 30, 824 (1971).
7) L.D. Landau and E.M. Lifshitz: Quantum Mechanics,
3rd ed., Pergamon Press, Oxford, Sect. 148 (1977).
8) M. Inokuti, 1. Shimamura, and Y. Itikawa: preprint(1988) .

49

RIKEN Accel. Prog. Rep. 22 (1988)

111-2-7.

Gamma-Ray Spectrum Due to the De-Excitation ofa Muonic Molecule paJ.l
S. Hara and T. Ishihara *The resonant state of a muonic molecule(pa,u), =1 composed of a proton p (or its isotopes

deuteron d and triton t), an a particle a, and anegative muon,u with a total angular momentum] = 1 is related to the muon transfer process(pa,u), =1~
a,u +p+y(1)(2)

We adopt Eq. 3 for the wave function of theinitial resonant state and the Born-Oppenheimer
approximation for the ground repulsive state.
Thus the wave function for the final state, inwhich the momentum for the relative motion of pand a is k, is given by
1jfJM=,.I..
EO

These processes are important since the mesic
atoms p,u and others contribute to the muoncatalyzed fusion reaction, whereas the final product a,u does not. Aristov, et al.I) and Kravtsov,
et al. 2 ) theoretically investigated the bound stateenergies of (pa,u), = 1 (and its isotopes) and theformation rate of (pa,u), =1 in process 1. The
resonant state (pa,u), =1 decays by electric dipole
transition into the ground repulsive a,u + p stateby y-ray emission (see Fig. 1). The lifetime of(pa,u), =1 and the y-ray spectrum for process 2
are studied by Kravtsov, et al. 3 ) using the BornOppenheimer approximation to the initial resonant and final repulsive states. An experiment is
now in progress to measure the y-ray spectrum
for process 2.4) Here, we reformulate process 2
and calculate the y-ray spectra and the lifetimeof (pa,u), =1 and its isotopes by using an exact
expression for the initial resonant state wavefunction.
The total wave function for (pa,u), = 1 and its
isotopes can be written in the following form(~

• R)X, (kR)

R

17 ,

c"

'P 1"

(2J+l)
87Z'2

1/2• D{;o ((/J, 8, cp)(4)

The ground state 10" orbital for pa,u (/J I" (~,17R) is determined by the following equation

I V~+1_~ __1 -eo(R) ] <P l"(~,rJ ; R) =0[ __2m
R ra}J rpl"
(5)
where r al" and r PI" are the distances between aand ,u, and p and ,u, respectively, and(6)

1/ m=1/ Ma+1 / m}J

Here M a and m}J are the masses of a and ,u,respectively. This choice of m gives the correct
dissociation limit for p + a,u in the BornOppenheimer approximation. The following
units are used throughout this paper\ ./'---'",.~-0.5H-....:::......:~/'===~-·------:-===-~- p,u+o-r(b)1jf'M=:~'m(~, 17; R) (2{~1) 1/2-LO t-• D{;m (~, 8, cp)(3)Here M and m are the components of the total
angular momentum J along a space fixed z axis
and along an internuclear distance vector R,
respectively, D{;m the rotation matrix 5 ) and R =I R I . A set of variables r(~, 17, cp) represents
spheroidal coordinates for the muon, 8 and (/Jare polar and azimuthal angles for the vector R
in the space fixed coordinates. The position
vector of the muon relative to the mid-point of pand a is represented by r.

>.

~
c

w

-1.5

-2.0

~\
k2
2M

~
I

I

5

10

o,u+p

15

20

R

Fig. 1. Schematic diagram for the de-excitation of(paj.t) J =1 in the units given in Eq. 7. (a), Adiabatic
potential energy curve Eo (R) for aj.t + p ; (b),adiabatic potential energy curve for pj.t + a ; and(c), probability density of the resonant state(paj.t)J =I,
I1J!JM(r, R) 1 2 dr 2n sin8d8. The
ordinate for curve (c) is arbitrary.

f* Institute of Applied Physics, University of Tsukuba.

E,

50

S. Hara, et at.

e= n =m=l(7)

The radial function X J (kR) satisfies the following equation[___
1 {~_L[±U}

2M dR2R2___1 2J+eo(R) 2Mk X,(kR)-O(8)with the boundary conditions,
XJ (0) =0(9)

X, (kR)~sin [kR -4f- ~ In(2kR) +0,

Table 1. Energies and lifetimes of the resonant state(pap) J =1 and its isotopes. (a), present; (b), Refs. 1
and 3 ; (c), Ref. 2.

pap
(a)
(b)
(c)

II M=11 Mp+11 M a

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

and Mp is the proton mass. The momentum k forthe relative motion is determined by

k2-50.02-41.6-43.7

5.20 X 10- 12
1.8 X 10- 12-57.84-55.9-57.5

5.90 X 10- 12
1.9 X 10- 12-63.53-62.9-63.9

6.03 X 10- 12
2.1 X 10- 12

tap

(ll)

EpaI' - c 0 (ex) = E y + 2M

Lifetime (s)dap

J (10)

where OJ is the phase shift including the Coulomb phase. In Eq. 8,

Energy (eV)(12)

where EpaI' is the energy of the resonant state,
and Ey the energy of an emitted photon.
The transition probability per unit time andunit energy, that is, the energy spectrum of y ray
is given by~~ =1(aE y)3 (27!~) r~~ (2!J ~ 1)•1

< lJl fs'g'

1

d 1 lJf' i ,M, > 1 2(13)8

where bracket denotes volume integral over R
and r, a is the fine structure constant, and d thedipole moment of paJ.l with respect to the centreof mass of the system;1d=- (1+2mf!) r---(-3Mp +M a -m)R

Uot

Uot

(14)

where

Mtot=Mp+Ma +m

(15)

JJ

In Eq. 13, three components of d give the same
contribution. The space fixed z-component of dcan be written in the formdz = 2.. D &~ (~, 8, rp) g). (~, 17 ; R)

(16)

).

where g). are the functions of ~, 17, and R. Substitution of Eqs. 3, 4, and 16 into 13 givesd~~=38Mk(aEy)3~J,m'i.C~ljf; m,-m)A(h, m)
1

JJ

where

12 (17)7C

f

AUf, m) = RdRXJ, (kR) (c/>lrr g-m c/>i,m)
1

1

(18)

In Eq. 18, the last parenthesis denotes the volume
integral over r except for an angle rp.
We have calculated the resonant state energies
of paJ.l (and its isotopes) ~aJJ and the wave
function lJ! j,M, with!J = 1, At.. = 0 by a variationalE, (keV)Fig. 2.

Gamma -ray spectra due to de-excitation. (a),pap~ap +p; (b), dap~ap +d; and (C), tap~ap+t.

method6,7) using 300-term trial functions. In Table
1, EpaI' are compared with those obtained byusing the Born-Oppenheimer approximation.!,:!)For the final state, ~lrr (~, 17 ; R) and cO (R) were
calculated by the method proposed by Bates andCarson. S ) Equation 8 for J = 0 and 2 were solved
numerically to obtain a radial wave function)0 (kR). We adopted the following massconstants: M a = 7,294.295 me, Mp = 1, 836 .151 me,
deuteron mass Md =3,670.481me, triton mass Mt= 5,496.899 me, and m I' = 206.769 me, where meis the electron mass.
The y-ray spectra are shown in Fig. 2.
The absolute value of intensities in the present
calculation is about 3 times smaller than those in
the previous one!) for all isotopes. The lifetime '(of the resonant states(19)

is also given in Table 1. The values are about 3
times larger than those of previous calculation. 3 )S. Hara, et al.

In our pajl spectrum, there is a small second
peak at Ey ~ 8 keY, with a peak height of about
1/22 of the main peak and with a half width ofabout 0.1 ke V.
References
1) Yu A. Aristov, A.V. Kravtsov, N.P. Popov, G.E.
Solyakin, N.F. Truskova, and M.P. Faifman: Sov. ].
Nucl. Phys., 33, 564 (1981).
2) A.V. Kravtsov, A.I. Mikhailov, and N.P. Popov: ].
Phys. B: At. Mol. Phys., 19, 2579 (1986).
3) A.V. Kravtsov, N.P. Popov, G.E. Solyakin, Yu A.

51

Aristov, M.P. Faifman, and N .F. Truskova: Phys.
Lett. A, 83, 379 (1981).
4) K. Nagamine: private communication; T. Matsuzaki,
K. Ishida, K. Nagamine, Y. Hirata, and R. Kadono:
Muon Catalyzed Fusion 2, 217 (1988).
5) M.E. Rose: Elementary Theory of Angular Momentum, John Wiley & Sons Inc., New York (1957).
6) S. Hara, T. Ishihara, and N. Toshima: ]. Phys. Soc.
lPn., 55, 3293 (1986).
7) S. Hara, T. Ishihara, and N. Toshima: Muon Cata·lyzed Fusion, 1, 277 (1987).
8) D.R. Bates and T.R. Carson: Proc. R. Soc. A, 234, 207(1956).

52
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-8.

State Densities and Ionization Equilibrium of Atoms
in Dense Plasmas
I. Shimamura and T. Fujimoto*

Recent developments in experimental studies
of dense plasmas have stimulated theoreticalefforts to understand spectroscopic properties ofatoms and ions in dense plasmas. These efforts
include calculations of the energy levels andStark broadening of bound states in many different models. They range from one-electron
central-potential treatment with or without nonspherical perturbation by other particles in theplasma, to many-particle treatment in whichelectron-electron and electron-ion interactions
are explicitly taken into account. Detailed calculations including many kinds of effects, however,are limited to low-lying bound states.
As in the study of ionization equilibrium, one
often finds it necessary to know the state densityof atoms in a plasma over the whole spectrum
from the ground and excited bound states to theentire continuum. This presents a difficult theoretical problem, partly because one has to deal
with an infinity of states, and partly because any
reasonable model for this problem and associated calculations should be consistent over thewhole spectrum.
In the conventional theory of ionization equilibrium in low-density plasmas, Saha's equation
is used in which any interactions between particles in the plasma are completely neglected when
dealing with electrons in continuum states (withan energy E > 0) .1) In other words these electrons
are regarded as free electrons that comprise an
ideal gas. For the hydrogen plasma this leads toa density of stategF (E / R) = (E/ R) 112 / (27C2ne~) (E > 0) (1)with the Bohr radius flo, the Rydberg unit R (=13.6 e V), and the number density ne of electrons.
On the other hand an electron in a bound state(with E < 0) is bound by the Coulomb interaction with a proton. Thus the state density is thatof the hydrogen atom, i.e.,gH(E / R) =1

E / R 1-5/2(E < 0)(2)This state density diverges as E approaches* Department of Engineering Science, Kyoto University.

zero from below, whereas gF (E / R) tends to zeroas E approaches zero from above. This unphysical discontinuity is due to the inconsistency
in the treatment in the positive-energy andnegative-energy regions.
To derive Saha's equation for low-density
high-temperature plasmas in thermal equilibrium, we take into account only low-lying levelsin the calculation of the partition function. Thus
the singularity in the state density is avoided inthis approximation. For high-density plasmas,
however, Saha's equation is well known to leadto unreasonable results; more elaborate treatment of the state density across the ionization
limit is necessary. In fact the ionization limit foratoms in dense plasmas shifts to the low-energyside, which is known as continuum lowering. It
has been theoretically studied in detail especiallyfor a partially ionized hydrogen plasma.
We present here a simple model for the densityof states of hydrogen plasmas that is continuous
across the ionization limit and that is consistentover the entire energy spectrum; the resultant
state density approaches gF (E / R) at high E andcoincides with gH (E / R) for low-lying boundstates. Ionization equilibrium of dense plasmas isalso discussed on the basis of this state density.
Consider a hydrogen plasma for which the ion
coupling parameter r, i.e., the ratio of a representative Coulomb energy e2 / rj to the kinetic
energy ks T, is larger than unity, where e is the
charge of an electron, ks is the Boltzmann constant, T is the electron temperature, and rj =(47Cne/ 3) - 1/3. A simple model appropriate for thiscase is the ion-sphere model that introduces a
sphere with a radius rj around a proton. The
sphere, called an ion sphere, has a volume 1/ ne ,and the probability of finding another proton inthis sphere should be almost negligible for r > 1.
We assume that the density of electronic levelsof the hydrogen plasma is approximated by thestate density of the hydrogen atom confined in an
ion sphere, i.e. , the density of levels held by theelectron -proton interaction potential - e2 / r surrounded by an infinitely high potential wall at
r = 11. This model is probably too crude for the

53

1. Shimamura, et al.

calculation of each energy level, and hence, forthe calculation of the level shift from a purehydrogenic energy due to interactions with otherparticles in the plasma. The interest here, however, is not in the level shift but in the global
structure of the level density. The present model
should be reasonable for this purpose, though nothighly accurate.
We apply the Bohr-Sommerfeld quantization
condition, which is known to reproduce exactly
both the density gH (E / R) of the purely quantal
levels of the hydrogen atom and the density
gF (E / R) of the plane-wave states in a vanishingpotential in a finite sphere. We define a dimensionless quantity X = (E / R) (rj/ ~). The density g (E / R) of states is calculated asg (E / R) = gH (E / R) G (a)=(rl/ ~)S/ 2IX I- S/2G(a)

(3)

,i
,
Hydrogen Model:,
,
,,
,,,
I

0.8
~

0.6

Co-'
$!

PresentI-'- 0.4
><

I

I
I

,
I

0.2

0.0

- 10

10

0

20

X

Fig. 1. Reduced density !X !- S/2G(a) ( = (r,/ao ) -S/2
• g (E / R» of electronic states as a function of X ( =(E / R) (r, / flo». Also shown are the reduced density ofthe bound states of the hydrogen atom and that of thefree states described by plane waves.

with
a=X(X+2)

(4)

where
G(a) = 7( - 1 [~a3/2- / a(a+I)+ In( /2 + / a + 1) ]for O<X(5)

G(a) =7( - 1 [ -~( - a)3/2- / -a(a+I)+sin- I / -a]for -1 <X <0(6)

G ( a) = Gcont (a) + Gmd (a)for -2<X <-1

(7)

with
Gcont(a) =7( - 1 [ - ~(-a)3/2 + / -a(a+1)-sin- I / -a-a7(]

(8)

and
Gt,nd (a) = a + 1(9)G(a) =1(10)

andfor X < - 2

The function I X I-S/2G (a) is plotted in Fig. l.
The asymptotic form (2/ 37() X3 of Eq. 5 forlarge X is consistent with Eq. 1 for the freestates. This is natural, since a weaker effect of
the Coulomb potential is expected for a larger
kinetic energy.

It follows that the above state density is continuous and smooth across X = 0, -1., and - 2,
and over the entire spectrum. Also, one findsthat the state density is a monotonically increasing function of the energy. The continuum portion of the state density rises linearly from zeroat X = - 2.
To study ionization equilibrium we assume
that the electrons in the plasma occupy the eigenstates according to the Boltzmann distribution.
The integral of this distribution over the continuum gives the number density nl of hydrogenions. The integral, or more accurately, the sum
over the bound-state spectrum gives the number
density no of neutral hydrogen atoms.
The correction factor on Saha's equation calculated in this way depends both on neand on T,
but only through r.
In conclusion, we note that the simple model
presented in this paper results in reasonabledensity of states and ionization equilibrium.
Because of its simplicity and of the useful scaling
relations, the model should be useful for many
future applications.

Reference
1) W. Ebeling, W.D. Kraeft, and D. Kremp: Theory ofBound States and Ionization Equilibrium in Plasmas
and Solids, Akademie-Verlag, Berlin (1976).

54
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-9.

Charge-State Distribution Measurements of 26-MeV /u Ar Ions
Y. Kanai, T. Kambara, T. Mizogawa, A. Hitachi,
K. Shima, and Y. Awaya

We have estimated mean charges of lowenergy « 10 MeV l u) projectile ions in the equilibrium charge-state distribution after passing
through a target material by using a semiempirical formula, where we neglected a shelleffect. 1) For projectile ions with energies ofhigher than 10 MeV l u, their mean charges are

not easy to estimate. When we do some experiments using RIKEN Ring Cyclotron, such information will be needed. As a first step in the datacompilation of equilibrium charge-state distributions of ions in the energy range of RIKEN Ring
Cyclotron, we carried out the measurement with
26-MeV l u Ar ions.

Table 1. Charge-state distributions of Ar ions after passing through targets. The incident charge
state and energy are 13+ and 26 MeV / u, respectively. Numbers in parentheses stand for the
power of ten. Statistical error is within ± 5 % of each value.
Charge state fraction
TargetMean charge

C (10 ,ug/ cm )C (20 ,ug/ cm 2 )C (40 ,ug/ cm 2 )C (80 ,ug/ cm 2 )C (173 ,ug/ cm 2 )C (600,ug / cm 2 )C (4.27 mg/ cm 2 )Be (25,um)
Be (50 ,urn)
2

13.91
14.62
15.33
16.83
17.11
17.91
17.98
17.97
17.97

12+

13 +

14 +

15 +

16 +

17 +

18 +

5.4 (-5)
2.6(-5)3.32 (-1)
1.19( - 1)
2.11(-2)
1.44 (-4)

3.98( - 1)
3.50( -1)
1.62 (-1)
4.45( -2)
8.7 (-5)( -7)
4

2.02 (-1)
3.46 (- 1)
3.80 (--1)
4.97(-2)
6.43(-3)
4.2 (-6)

6.29(-2)
1.64 (-1)
3.49 (-1)
1.78 (-1)
1.34 (-1)
1.86 (-3)
1.24 (-4)
1.08 (-3)
9.98 ( -3)

4.7 (-3)
1.92( -2)
8.10(-2)
6.40 (-1)
5.96 (-1)
8.19(-2)
2.00(-2)
2.90 ( - 2)
2.95(-2 )

1.4 (-3)
1.2 (-3)
6.4 (-3)
1.27 (-1)
2.63 ( -1)
9.16(-1)
9.80 (-1)
9.70( - 1)
9.65 (-1)

Ar l3+ ions of 26-MeV l u were momentum analyzed and passed through target foils ( carbon 10,ug/ cm 2 - 4.2 mg/ cm 2 and beryllium 25 and 50,um
in thickness). The charge-state distributions of
Ar ions after passing through the target were
measured by a combination of a chargeanalyzing magnet and a position-sensitive
parallel-plate avalanche counter (PP AC) located just behind the magnet. 2 ) Results are summarized in Table 1.

1.1 ( -5)
1.0 (-5)

Analysis is now in progress. Using this data,
we intend to improve the semi-empirical formulaand extend the applicability to projectile ions up
to 26-MeV l u.
References
1) K. Shima, T. Mikumo, and H. Tawara: At. Data
Nucl. Data Tables, 34, 147 (1986).
2) Y. Awaya, Y. Kanai, T. Kambara, and T. Chiba: This
Report, p. 149.

55
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-10.

Multiple Inner-Shell Ionization of Target Atoms
by 0.8-26 MeV /u Heavy-Ion Impact

Y. Awaya, T. Kambara, Y. Kanai, T. Mizogawa,A. Hitachi, and B. Sulik
Systematics of simultaneous single K and
n1ultiple L shell and single L and multiple M shellionization of target atoms was studied previously by using 4.7-S.2-MeV l u heavy ions accelerated
by the cyclotron. 1•2 ) K-satellite and hypersatellite
X-rays or L-satellite X rays from various target
elements were measured by using a stepscanning crystal spectrometer. Projectiles were
He, C, N, and 0 ions. We obtained not only the
L-shell ionization probability accompanied bysimultaneous K-shell ionization, PL , but also theM-shell one accompanied by simultaneous Lshell ionization, PM' We also studied the ratio ofthe double K-shell ionization cross section to thesingle ionization cross section from the intensity
ratio of the Ka hypersatellites to the Ka satellites.
After RIKEN Ring Cyclotron (RRC) started towork, we expanded the previous work to ahigher incident energy range. At the same time,
we made other measurements at lower energies
by using the linear accelerator (RILAC). We
used 26-MeV l u N ions from RRC and 0.S4-, l.1-,
1.3-, and l.6-MeV l u N ions from RILAC as projectiles. Targets were 1-2-,um Ti, Ni, and Cu foils
and a piece of Fe wire of 25 ,urn in diameter forthe measurements at RRC and a 2-,um Ti foil for
those at RILAC. The K X rays from the targets
were measured by using a broad range crystal
spectrometer3 ) with a flat crystal and a positionsensitive proportional counter. A crystal of LiF(2 0 0) was used for the measurement of Ti and
Fe K X rays and that of LiF (2 2 0) for Ni and Cu
K X rays.
A spectrum of the Ti Ka satellites and hypersatellites and a part of the K.a satellites obtainedby 26-MeV In N-ion impact on the Ti target isshown in Fig. 1, where KL n denotes the initialstate vacancy configuration. For the 26-MeV lu
N-ion impact, a high-level background caused by
y rays induced by nuclear reactions is expected,
but the broad-range X-ray crystal spectrometer
was found to work sufficiently at this high incident energy.
The experimental values of PL obtained from

!l.5

5.0

E(keV)

300

Fig.1. Spectrum of Ti K X-rays obtained by 26-MeV l u
N-ion impact.

1.0~----------,

0.5

0.05

previous datao P L (n=2)
o PM(n=3)

o

4

2

6

Vtlv"

Fig. 2. PL values obtained by the present work:
0 , obtained by 26-MeV l u N-ion impact; ., by 0.84 1.6-MeV l u N-ion impact and Vi corresponds to incident energy; x and @, explained in the text. Previ·
ously obtained PL and PM values are also shown. Solid
curve is the universal BEA one for k = do l (27r~'Ry).
Dashed and chain curves are normalized ones.

Ka satellites are shown in Fig.2, where the open
circles show those obtained at RRC and closed
circles at RILAC together with the previous
data. 1•2 ) The solid line is the BEA universal
curve. 4 ) Scaled parameters of n 2 un Pn i kZ j 2 and56

Y. Awaya, et at.

VII Vn were adopted to fit the theoretical curveto the experimental values of both PL and PM,
where n is the principal quantum number, Un thebinding energy of n-shell electrons (n = 2 for L
shell and n = 3 for M shell), Un the binding energyof an n-orbital electron, ZI the nuclear charge of
projectile heavy ions, Vi the velocity of the
projectiles and Vn that of n-orbital electrons.
The constant k is represented as <50 1 (27C~2 Ry),
where <50 = 7Ce\ ao is Bohr radius and Ry = 13.6
eV. The energies of the projectiles are taken as
the incident ones to estimate Vi and the value of
Zt is taken as 7 but we should make some comments on these parameters.
The energy loss of the 26-MeV l u N ions in atarget foil is smaller than 0.4 percent of theincident energy and the mean charge of ions incharge equilibrium is almost equal to 7.0 +. Thismeans no correction is required for Vi in the
reduced parameter.
On the other hand, the Ti target (2 fJ. m) is notthin enough for 0.8-1.5-Me V l u N ions; for example, total energy loss of N ions in the target isabout 4 MeV for 1.5-MeV lu (total energy: 21
MeV) incident energy. It may be reasonable totake the incident energy of the projectile toestimate Vi. The K-shell ionization cross section
decreases drastically with decreasing energy of
projectile ions in this collision system, whereas
the change of L-shell ionization cross section is
not so much because the velocity of Ti L electron
and that of the projectile is comparable in thiscollision energy. Since we observed the KLn
X rays, the production cross section of these X
rays depends on mainly by the K-ionization crosssection. For the reference, the points are plottedby crosses for the values which correspond to theprojectile energy after passing through the half
thickness of the target.
Another factor to be considered for low energy
impact is the value of ZI in the scaled parameter.
When we take the mean charge of N ions incharge equilibrium at the energy at the half
thickness of the target foil, the corrected experimental data move to the position shown by crosses surrounded by circles. This is the mostextreme case and it is difficult to discuss effective ZI values for the multiple ionization process.
In the previous study, we found that the universal curve multiplied by a factor of 0.84 fits betterto the experimental values of PL and that by 1.25
does to the values of PM. When we add the PL

values obtained in the present study at RRC, thisbecomes more plausible. The broken curve in
Fig. 2 is the universal curve multiplied by 0.84
and the chain curve is that by 1.25. This meansthat the estimated value of the cutoff radius in
the calculation is about 10 % smaller for L shelland that for M shell is about 10% larger.
As is seen in Fig. 2, the experimental dataobtained by RILAC corrected for the energy lossof the projectiles and charge are fitted well by
the universal curve. In order to check the validityof this correction, we are planning remeasurements by using a very thin target where
the effect of the energy loss of projectiles isnegligible; this will at least make clear the ambiguityof Vi.

0.4~........

0.3

~ 0.2
0.1

.•

•

••

!l

0

O~------~------~------7

Fig. 3. Intensity ratio of Ka hypersatellites to hypersa telli tes vs. E / A. Ut<. 0 , present data; ., previ ous
ones. I )The preliminary results of the intensity ratioof the Ka hypersatellites to the satellites, Kh al Ka
for 26-MeV lu N-ion impact are shown in Fig. 3,
with the previous data of N-ion impact. E is thetotal incident energy and A is the projectile massin electron mass units. It seems that the values ofKh alKa take a constant value at high energy
bombardment, though the data has large uncertainties arising from the estimation of the background. The analysis is in progress.
References
1) Y. Awaya: Electronic and Atomic Collisions, Proc. XI

ICPEAC (eds. N. Oda and T. Takayanagi) North
Holland Pub. Co., Amsterdam, p. 325 (1979).
2) Y. Awaya et at.: IPCR Cyclotron Prog. Rep., 13, 76(1979) .
3) A. Hitachi, H. Kumagai, and Y. Awaya: Nucl. Instrum. Methods, 195, 631 (1982) .
4) J. H. McGuire and P. Richard: Phys. Rev. A, 8, 1374
(1973) .

57
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-11.

Resonant Transfer and Excitation (RTE)in Ge 31 + on H2 Collisions

S. Reusch, * P. H. Mokler, * T. Kanlbara,R. Schuch, ** G. Wintermeyer, ***A. Muller, **** Z. Stachura, ***** and A.W arczak ******The resonant transfer and excitation (RTE)
process is important among the electron transfer
processes in collisions between high-velocity
highly-charged ions and light atoms. RTE is acollision process in which an electron excitationin the projectile ion and a transfer of a target
electron to the projectile occurs simultaneously
through an electron-electron interaction. Since
the excitation and the transfer are correlated, theenergy required for the excitation should matchthe energy gained by the transfer. Therefore
RTE is a resonant process which occurs only at
specific collision energies. When a free electron
instead of a bound electron in a target atom ormolecule is transferred to the projectile, thisresonant process is called dielectronic recombination (DR) which is the inverse process of anAuger electron emission. The resonances of RTE
and DR are named in accordance with the corresponding Auger processes.
We have investigated the KLn-RTE process( n = L, M,"') in collisions between highly
charged Ge ions and a I-L target at the UNILAC
facility of GSI (Gesselschaft fUr Schwerionenforschung ; Heavy Ion Research Institute) in Darmstadt. An experiment with incident Li-like Ge 29 +ions was reported previously. I) In that ex peri ment, the projectile ions were charge-analyzed
after the target and those which captured one
electron were counted in coincidence with thecharacteristic X rays of the projectile. The projectile energy was changed between 12 and 18.5
MeV /u to get an excitation function.
When the projectile is a H-like ion, it gets a
doubly-excited He-like ion after a KLn-RTE* GSI, D-6100 Darmstadt, F. R. Germany.
** AFI Research Institute of Physics, S-10405 Stock holm, Sweden.
*** Physikalisches Institut, UniversiUit Heidelberg, D6900 Heidelberg, F. R. Germany.
**** Strahlenzentrum, Universitat Gie13en, D-6300
GieSen, F. R. Germany.
***** Institute of Nuclear Physics, :~1-342 Krakow,
Poland.
****** Institute of Physics, Jagiellonski University, 30059 Krakow, Poland.

process and it can decay with two K-X-ray
photon emissions as shown in Fig. 1. RTE can beobserved by coincidence measurements between
two K-X-ray photons besides the coincidence
measurements between X ray and charge
exchange like previous report. I) We can get informations about the electronic state of the projectile ions after the RTE process by measuring theenergies of the two X-ray photons.
Here we report the measurements of the KLn(n = L, M,"') resonances of the RTE process incollision between H-like Ge 31 + ions and a H2target by a two-photon coincidence method.
The experimental set-up is shown in Fig. 2. A
Ge 31 + -beam from the UNILAC was collimatedand was led to a differentially-pumped gas target
at a pressure of about 0.7 mbar. Two Si (Li)detectors placed at 90 to the beam direction and0>. _--

TargetL --+-+---+-+-

~
Q)

'0'

d::

K ___...---+-+RTE

Decay

Fig. 1. KLL-RTE process and two-photon decay of the
doubly-excited state after RTE in case of a H-like(one-electron) projectile ion shown in the projectile
frame.

Si(Li)l

AUFKQ3Gas

TargetSSD

FC

Si(Li)2

Fig. 2.

Experimental set-up.

58

S. I{eusch, el at.

opposite each other detected the X rays from thetarget region. Beam currents were monitoredwith a Faraday cup. An Au-foil was set before
the Faraday cup and scattered Ge-ions werecounted with four surface-barrier detectors at ascattering angle of 7.W. The number of the scattered ions were used for the normalization of thenumber of incident ions. Events of two-photon
detection with the two Si (Li) detectors wereaccumulated with a coincidence circuit andrecorded on magnetic tapes on a PDP 11 / 45
computer.
Figure 3 shows the correlation between
energies of two X rays measured by the two
Si (Li) detectors at projectile energies of 13 and16.5 MeV lu. At both projectile energies, there
appears a group of events around E, = E"!. = 10.5
keY which corresponds to two Ka-X-ray emissions from doubly-excited Ge 30 + ions. At 16.5
MeV l u, there are two other groups of events
around (E, = 10.5 keY, E"!. = 12 keY) and (E, = 12
keY, E"!. = 10.5 keY) which correspond to one Ka
and one Kpy-emissions. These events result fromradiative decays of 21nl' states with n > 2 of
Ge 30 + ions. Events along a line E, + E"!. = 10 keY
correspond to the two-photon 2El decay of 1s2s
'So singly-excited metastable state of Ge o+ ions.

This state can be produced by the El decay of adoubly-excited state like 2s2p IP, state. The
events along lines of E, = 10 keY and E"!. = 10 keV
correspond to the detection of a K X-ray from adoubly-excited state to the Is2s ISo state and oneof the two photons from the 2El transition of theIs2s 'So state.
Figure 4 shows the cross section of two K-Xray-emission as a function of the projectile
energy between 12.1 and 18.8 MeV l u. Dots show
the experimental results. Circles are for the total
K-X-ray-K-X-ray coincidences and triangles arefor Ka-Kpy coincidences which are from 21nl'(n > 2) states. Curves show theoretical predictions calculated by folding DR cross sections
with the Compton profile of a molecular hydrogen and corrected for the radiative transition
probability: Dashed curve shows the total coincidence cross section and dotted curve shows thecomponent of the Ka-K py coincidence cross section. Arrows show the energies of the Dl~ resonances calculated by a multi -configuration
code. "!. )Excitation Function
1000

BOO

c
(;;

600

::9

Coincidence X-Ray Spectrum

Z 400

14

"0

200

12

>1

12

Q)

14

~

16

IB

20

Beam Energy (MeV lu)

N

W

Fig. 4. Cross section of simultaneous doublc K-X-ra yemissions for (;e:11 i on II I collision at projectile cllergies
between 12.1 a nd 1H.H MeV l u. Dots show the experimental data , curves show theoretical predictiolls, Clndarrows show theoretical energies of K Ln -DI{ resonances.

14
12

Excitation Function 2El

>1
Q)

~
200

N

c

W

(;;

::9

E1

8

10

12

"

(keV)

0

~

." +

+\1 f -' \. + + +,f
H ,.... ~.".,
...J
...J
~

~

~~

II I I I

I

50

6

~

t,

~ 100

x

"0

3S .§

3

,+'1".,

150

12

\

14

16

18

20

Beam Energy (MeV lu)

Fig. 3. X-ray energy correlation diagrams at projectile
energies of 13 (upper) and 16.5 MeV l u (lower). HI and
E-"'z show the energies of X rays measured by each of the
Si (Li) detectors in coincidence.

Fig. 5. Cross section of 2E1 photon emission frol1l a
metastable 1s2s ISII state of (;e:11l1 as a functioll of thebeam energy. Descriptions of the dots, curve, andarrows are the same as those ill Fig. 4.

S. Reusch, et ai.

The cross section of two K-X-ray emission has
a maximum at about 13 MeV l u, a minimum atabout 15 MeV lu, and a maximum at about 17
MeV lu. The peak at about 13 MeV l u corresponds to the KLL-RTE processes. In this region
the Kpr X-rays are not observed. This is expected since the final state of the KLL-RTE processes are 2121' which can emit only Ka X-rays. The
agreement between the theory and the experiment is good. The peak at about 17 MeV lu issum of unresolved KLn-RTE resonances withn > 2. In this region, both the Ka-Ka and Ka-KPr
coincidence events are observed. The theoreticalprediction is about a half of the experimental
data in this region.
Figure 5 shows the cross section of 2E1 photon
emissions from the ISo-metastable state as a59function of the projectile energy. Dots show
experimental data. The curve shows theoreticalprediction, like those in Fig. 4, using the crosssections of DR processes leading to the statesfrom which radiative transitions are allowed to
the ISO state. The agreement between the theory
and the experiment is good for both KLL andKLM-RTE processes.
References
S. Reusch, Y. Awaya , T. Kambara, D.]. McLaughlin,
P. H. Mokler , A. Muller R. Schuch, and M. Schulz:
RIKEN Accel. Prog.Rep., 21, 71 (1987) .
2) LP. Grant, B.J. McKenzie, P.H. Norrington, D.F.
Mayers, and N.C. Pyper: Comput. Phys. Commun.,21,1)207 (1980 ).

60

RIKEN Accel. Prog. Rep. 22 (1988)

111-2-12.

Studies on the Continuum X Rays Produced
by Heavy-lon-Atom Collisions
K. Ishii, K. Maeda, Y. Sasa, M. Takami,
M. Uda, and S. Morita *Continuum X rays of radiative electron capture (REC) and molecular orbital X rays (MO)can be produced by heavy-ion/ atom collisions.
REC X rays are the quanta emitted by theradiative transition of target electrons into abound orbit of the incident ion. On the other
hand, MO X rays are emitted from the molecularorbitals or united atoms in adiabatic collisions
between an incident ion and a target atom. The
MO process is enhanced when the energy levelsof target electrons coincide with those of projectile electrons, especially, a symmetric collision.
Anholt has systematically investigated the crosssections for production of MO X rays and has
shown that the continuum X rays can be considerably observed even in asymmetric collisions
and the production cross sections of these continuum X rays are much larger than the predictionsfor MO X rays. 1) Ishii and Morita explained these
X rays in terms of the bremsstrahlung producedin ion-atom collisions, namely, atomic bremsstrahlung (AB).2)
Since the dipole transition process is predominant in atomic bremsstrahlung, the cross sectionof AB is almost zero in the case of symmetriccollisions and it becomes large for asymmetriccollisions. Production of AB is complementary tothat of MO. Molecular orbits can be formed in an
adiabatic collision process and so, when the incident energy becomes higher, the production crosssection of MO X rays decreases. Moreover, theMO X-ray energy cannot exceed the K X-ray
energy of the united atom (I U.K,). For higher
incident energy and in the region of X-rays
energy (nw > 1 U.KJ, the contribution of MO X
rays can be neglected and the behavior of AB forsymmetric collision is expected to be well studied.
In order to study the behavior of atomic bremsstrahlung in heavy-ion collisions, we bombarded
thick targets of C, BeO, NaCI, CaC0 3 , CaF 2 , AI,
Si, Ti, Cr, Fe, and Cu with SP+ ions 0.435 Me V /* Research Center of Ion Beam Technology, Hosei
University.

amu). The targets of BeO, NaCI, CaC0 3 , and
CaF 2 were coated with carbon in order to avoid
electronic charging up at the surface. A polyethylene foil (500JLm), Al foils of 140JLm or 230JLm,
or a vanadium metal foil (40JLm) was put
between the target and the Si(Li) detector.
In Fig. 1, the X-ray yields obtained n (Z p, Z T,
11) are plotted as a function of target atomic
number Z T for the normalized X-ray energy 11 =0.7, 1. 0, 1. 3, 1. 5, and 1. 8. n (Z p, Z T ,11) isdefined byd(J'Bremsn (Z p,Z T,lI) = nw

f Ndx dnwd (nw,
Q

e)

where
lI=nw / l u.K ., 8=135°, and Zp=14.
Si 3+ 1.435MeV /omu
8 L .,35 0

V' 0 .7

v·I .Ov o l.3

10

20

Fig. 1. Target-atom dependence of the continuum X·ray
yield produced by 1. 435 Me V/ amu Si-ion bombardments.

K. Ishii, et al.

For the target atomic number Z T of the compounds, we take the largest one of the component
elements. The experimental cross sections
decrease monotonously with increase in Z T
while the theory predicts a minimum at Z T = 14.
We can find that the atomic bremsstrahlung is
still effective in the case of symmetric collision.
This result leads us to consider that the electronsof projectile and target atom don't occupy each61

other a same orbit, and this effect prevents thesymmetric collision in a sense of atomic structure. Thus the quanta of dipole transition can beemitted even for Z p = Z T . The theory of AB will
be developed on the base of above model.
References
1) R. Anholt: Z. Phys. A, 289, 41 (1978).
2) K. Ishii and S. Morita: Phys. Rev. A , 30, 2278 (1984).

62
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-13.

Target Thickness Dependence of Charge State Fractions of
Ar Ions after the Passage through C-Foil, CH 4 , and H2
T. Mizogawa, Y. Awaya, T. Kambara, Y. Kanai,
M. Kase, H. Kumagai, and K. Shima

It is well known that the equilibrium mean
charges of fast heavy ions after passing throughsolid media are larger than those of ions passing
through gaseous media. 1) The origin of this "solid
effect" is still a problematic issue. To study thisproblem we have measured the charge-state
distributions (CSD) of 50 MeV Ar ions after thepassage through carbon foils and gaseous targets, CH 4 and H 2 •The experimental setup is shown in Fig. 1.
The essential points of the experimental procedure are as follows. The 50 MeV Ar ions fromRILAC were used. The charge fractions of argon
385

550

ions after the passage through the carbon foil
(2'"'-' 10 ,ug/ cm 2 ) or gaseous targets (;S 20 Torrcm for CH 4 , ;S 50 Torr cm for H 2 ) were measured for two initial charge states (4+ and 12 + ) .
After the passage through the foils or a gas cell,
the ions entered a charge-analyzing magnet, andwere finally detected by a position-sensitive
parallel-plate avalanche detector (PPAC). The
charge-state distributions were determined fromthe charge spectra obtained by the PP AC.
In Fig. 2 the charge fractions of Ar ions measured for the CH 4 target are plotted as a functionof the target pressure. The results for the C-foil

290

2270

AnalyzingfE----3;);.rIE-E-..;>tE~;)rE'----------->>-l1 Magnet
Gas Inlet--'---'--~

TMP

ITMP .rl~TMPI

TMP

Beam

~);ce
.~~e
r a,tfI\

Orifice
10 ct>

5ctJ

Tube

Position-sensitive

2ctJ

PPAC

Fig. 1. Experimental setup for Ar·ion charge-state-distribution measurements with gaseous
targets. For the solid target measurements the gas cell is replaced by a target holder.
Ar4+ ....

CH 4

Ar12+ ....

CH 4

12+
4+

11+
10+

5+
8+
.1

7+

.1

8+

Z
0
~

9+

11+

Z

0

i=

9+

(J

<

IE .01
W

(J

13+

u..

10+

<
0:
10+

B+
14+

W

(!)

<:)

0:

<
J:

a:
<
:c

11+

(J

14+

(J

.001

.001

7+
9+

15+

12+

.0001
.001

.01

PRESSURE.1(Torr)

.0001
.001

.01

PRESSURE.1(Torr)

Fig. 2. Target-pressure dependence of charge-state fractions of 50 Me V Ar ions after
passage through CH 4 •63

T. Mizogawa, et al.

Ar 12+... C foil

Ar 4 + ... C foil
100

100

~

10

s:l

<IS

r:r..

<=:~/~it~ 14+ ~

~0
I-<

12+

12+
13+
11+

10+

s:l

15+

:3
0

<IS

1

I-<

r:r..

9+

:

~

:

:-14+
10+
:

15+
-9+

j

<IS

ti
<1>

<:

~

~

bo

10

U]

16+

<1>

.1

bo

~_16+

.1

I-<

I-<

8+

<IS

~

-8+

'"

~

0

0

.01

.01
7+

------ -

1+

10

15

.001

.001
0

5

10

0

15

5

Target Thickness (llg/cm 2 )Target Thickness (lJg/cm 2 )Fig. 3. Target-thickness dependence of charge-state fractions of 50 MeV Ar ions after
passage through C foils.

targets are shown in Fig. 3. From these data themean charges were evaluated and plotted in Fig.
4 as a function of the carbon thickness of thesolid target or the CH 4 gas. The mean charges
for the solid target change with the carbon thickness more rapidly than those for the gaseous
target before reaching the equilibrium values.
The equilibrium mean charge for the solid target
is + 12 . 33, which is larger than the case of thegaseous target by + 1. 55 .
Our previous measurements of the intensities
of Ka and K.s satellites of Ar ions passing
through C foils 2) show that the sum nL + nM ofequilibrium average numbers of L-vacancies(nL=4.45 ± O.05) and M-vacancies (nM=7.65±
0.25) in K-vacancy bearing ions is 12.1 ±O. 3. If
we assume that these L- and M-vacancy numbers
are nearly the same as those for ions without K
vacancies, the sum nL + nM averaged over all Ar
ions would be about 12.1 , which is in good
agreement with the equilibrium mean charge
12.33 for the carbon foil. This assumption isreasonable, because the L- or M-vacancy production is probably independent of the K-vacancy
production, and also because the L- or M -shell
equilibration time is shorter than the K-vacancy
mean life in solid. Then the above agreementmeans that, if there is no auto-ionization process
faster than K-vacancy decay, the solid-gas difference + 1. 55 should occur inside the solid and/ or
outside the solid as close to the exit surface as no
autoionization processes can take place, because
K X-ray emission occurs in such a region. The
LLM Coster-Kronig process is energetically for-Ar 12+

11

~
a::
~

-. CH

.-;/;0\-'"---....

4' - 10.78:1:.06,/

9v~t;,. / 'Z«t;,.x ~
7

/

/

~ /

./ .
5

--:;"'-..-- -

./ '

10

U

~

12 +

-+ C fO~f=_+_ ••- t 12. 33 :1:.10
C \0\\. ___... . , / f',tAr

- . -.__

12

q eq [solid] - q eq [gas]= 1.55±.12/

4~~~~~~~~W-~~~WL~~Lll~

.01

.1

TARGET THICKNESS

10

100

(J.lg/cm2)

Fig. 4. Target-thickness dependence of the mean
charge of 50 MeV Ar ions after passage throughC foils or CH 4 •bidden for multiple L-vacancy bearing states,
and the LMM Auger decay may be slower thanK-vacancy decay. Therefore the "Betz-Grodzinsmodel,"l) which attributes the solid-gas difference in equilibrium mean charge to the fastauto-ionization of excited electrons outside theexit surface of solid targets, is considered to be
not valid in the present collision system andenergy. The difference may be attributed tosuccessive L to M excitation and M to continuum
ionization inside the solid.
In this discussion we neglected the existense offour H atoms in a molecule CH 4 • To assess therole of them, we also measured the CSD of Ar
ions after passage through H2 gas. The resulting

64

T. Mizogawa, et at.

Ar4+~

H2

Ar12t ~

H2

4+

.1

5+
.1

Z
0

6+

~

7+

~

~
U

a:
u..

z

o

.01

W

u
~
a:
u.. .01

B+

W

(!)

(!)

a:

a:
~

9+

~

:r:

:r:

u

(J

.001

10+

11+
. 0001
.001

.01

.1

.01

PRESSURE (Torr).1

PRESSURE (Torr)

Fig. 5. Target-pressure dependence of charge-state fractions of 50 MeV Ar ions after
passage through Hz.

CSD and the mean charge of Ar ions are given in
Figs. 5 and 6, respectively. The explanation forthe horizontal scale of Fig. 6, "equivalent C
thickness," will be necessary. In Fig. 4, we used
the C thickness in units of [,ug / cm2] as ahorizontal coordinate, for convenience of thecomparison of "solid" and "gas" cases. To compare the results for CH 4 targets and H2 targets, itwill be convenient that the same numerical values of the horizontal coordinates of Figs. 4 and 6
give the same H-atom thickness. The "equivalentC thickness" is such a variable which is proportional to the adopted H2 pressure.
From these data we can deduce some qualitative conclusions. First, from the thin limit of
Ar l 2+ -ion data, the electron capture cross section
from H2 is negligibly small compared with thatfrom CH 4 • Second, from the thin limit of Ar4+ion data, the electron loss cross section for the H2target is a few tens of percent of that by the CH 4
target. Therefore, in the charge-equilibration
process of Ar ions in the CH 4 gas, the role of H
atom is rather enhancement of electron-loss thanelectron-gain, provided the simple assumption,i.e., that the charge-changing cross sections formolecule targets are approximately equal to thesum of the cross sections for the constituent
independent atoms, is valid. This means that, if"pure carbon gas" is used as charge-stripping

12

11

~
a:
<t

10
9

J:

U

Z

<t

8

w

:2

7
6

5

4 ~~LWUllll--L~~W-~~~~~~~~
.01.1
10
100

EQUIVALENT C-THICKNESS(\Jg/cm2l

Fig. 6. Target-thickness dependence of the mean
charge of 50 Me V Ar ions after passage throughH2 •media, the above "solid effect" in the equilibriummean charge will be further enhanced.
References
1) H.D. Betz: Rev. Mod. Phys., 44, 465 (19 72).
2) T. Mizogawa, Y. Awaya, T. Kambara , Y. Kanai, M.
Kase, H. Kumagai, P.H. Mokler, and K. Shima:
RIKEN Accel. Prog. R ep., 20, 53 (1986); T. Mizogawa,Y. Awaya, T. Kambara, Y. Kanai , M. Kase,
H. Kumagai, P.H. Mokler, and K. Shima: N ucl. Instrnm. Methods Phys. Res. A , 262, 141 (1987).

65
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-14.

Charge Distributions of the Recoil Ions Accompaniedwith Multiple Ionization of Heavy Projectile Ions
H. Tawara, T. Tonuma, H. Kumagai, and T. Matsuo

Presently it is known that under highly
charged, energetic heavy ion impact multiply
charged recoil ions are copiously produced, in
contrast to structureless particle (electron or
proton) impact. In particular, in collisions withheavy ions having inner-shell vacancies, the production of multiply charged recoil ions is significantly enhanced. This is understood qualitatively
as well as, to some extent, quantitatively to be
due to the (inner-shell) electron transfer fromtarget atoms into projectile vacancies. In fact,
Gray, et at.I) and Kelbch, et at.,2) for example,
have shown that the charge distributions ofrecoil ions are shifted toward higher charge statewith increasing the number of electrons captured
into projectile ions.
Taking into account the importance of suchtransfer ionization where the projectiles capture
electrons from target atoms and result in the
production of multiply charged recoil ions,Horbatsch 3 ) has developed a quantum statistical
time-dependent mean-field theory and calculated
the cross sections for transfer ionization as wellas those for pure ionization over the energy
region ranging from 50 ke V / amu to 5 Me V / amu
for projectiles with the ionic charge of 6, 12, and
20. This calculation suggests that the contribution of electron transfer processes becomes muchsignificant at lower energies, compared with thepure ionization process.
On the other hand, very few experimental andtheoretical investigations have been devoted
toward understanding the mechanisms of recoil
ion production when the ionization of partiallyionized projectiles is accompanied simultaneously (loss ionization). Ullrich, et at.4) have measured the cross sections for multiply charged
recoil ions in Ne q + (q = 1, 2, 3) + N e collisions at
relatively low energies (75- 360 keY / amu). Theirresults show that highly charged recoil ions aremainly produced in close collisions, whereas
recoil ions with low charge are due to puremultiple ionization under collisions with large
impact parameters. In their collision energy
region, two neon collision partners tend to form
a quasimolecule probably within the L-shell orbit

range of partially ionized neon ions. In fact, theobserved charge distributions seem to be similar
for both projectile and recoil neon ions and suggest us that the remaining electrons involved incollisions are equally shared between two collision partners.
In the present work, we measure the charge
distributions of recoil ions which are produced incollisions of partially ionized (N e q+ and Ar q+)
projectile ions with Ne atoms with simultaneous
ionization in both projectile ions and target
atoms. A TOF technique based upon chargeseparated projectile-recoil ion coincidence isused. 5 ) 1. 05 MeV / amu N e2+ and Ar4+ ions areprovided from RIKEN linear accelerator(RILAC) and, after passing stripping foils and aswitching magnet if necessary, sent into a collision chamber whose pressure is controlled. The
projectile charge state after collisions is analyzed with an electrostatic charge separator andfinally the projectile ions are detected with aposition-sensitive parallel plate avalanche
counter. On the other hand, recoil ions are detected with a channeltron detector after flying overabout 15 cm from the collision region.
Typical recoil ion charge spectra are shown in
Fig. 1. The charge-selected projectile-recoil ion
coincidence spectra are accumulated through
LIST mode. In Fig. 1 (a) is shown the charge
distribution of 1.05 MeV / amu projectile Ar q'+ions in coincidence with recoil Nei+ ions in theincident Ar4+ ions colliding with Ne atoms. We
have found that, at the present collision energy,
probabilities of 1- 4 electron ionization fromprojectile Ar4+ ions resulting into Ar 5 +-Ar 8 + ionsdecreases slowly toward higher ionization stage
and is far intense, compared with those for electron capture into projectiles resulting into Ar 3 +ions. The probabilities for further ionization
beyond q' = 8 are found to be also quite small, ·compared with those for q' ~ 8. This is due to aso-called shell effect where the ionization for
q' > 8 needs the ionization of 2p shell electrons
and, thus, much larger energy transfer to targeta toms is necessary.
At the present collision energy, the dominant

66

H. Tawara, et al.

i

1.0SMeV / amu ArH + Ne->Aro'+ + Ne +

6

10

10

7

10- 16

q' =3

q'=
x

10 1

4

5
• 6
6

a

o

§ 10-

Q

17

''::;

-l
W

o

(J

7

8
total

CIJ

Z

en
en
en

u
.......

U

Z

«
J:

o

(/)

t-

10- 18

Z

:::>

o
u

10- 1923456
Recoil ion charge (j)8Fig. 2. Partial cross sections for the production ofrecoil ions with different charge in coincidencewith the specified projectile charge after collisions
in 1.05 MeV / amu Ar4++ Ne collisions.
512

CHANNEL NUMBER

Fig. I, Observed charge spectra of both projectiles(a ) and recoil Ne i + ions (b-f) in coincidence with thespecified projectile charge q' in 1. 05 MeV / amu
Ar4+ + Ne collisions.

mechanism of the production of recoil ions withlow charge (i = 1-3) is believed to be pure ionization of target atoms without any change of projectile ion charge where probabilities for multiple ionization decrease drastically with increasing the charge of recoil ions (see Fig. 1 (b» . The
collisions accompanying one-electron (single)
ionization of projectiles clearly result in relative
enhancement of the production of recoil ionswith higher charge state (see Fig. 1 (c) ) ,compared with that of lower charge ions.
Furthermore, two-, three-, and four-electron
ionization of projectiles results in successively
higher charge recoil ions (see Fig. 1 (d), (e),and (f». In fact, for four-electron ionization ofprojectiles (resulting in Ar 8 +) , Ne4+ recoil ions
are most intense, with a trace of up to Ne+ to
Ne 8 + ions.
In Fig. 2 are shown the cross sections for the
production of recoil Nei+ ions estimated from theabove data and normalized to the previous
values 6 ) as a function of the recoil ion charge.

This clearly shows that, with increasing thedegree of simultaneous ionization of projectiles,
the production of recoil ions with higher charge
is significantly enhanced.
Similar trends are also seen in Ne 2 ++ Ne collisions (not shown here) where, though absolute
cross sections are smaller than those in Ar4+
collisions as measured in our previous
experiments 6 ) because of the low projectile q,
three-electron ionization of projectiles (the final
projectile charge being Ne 5 +) results in the production of recoil Ne 3 + ions with the highest
probabilities, having weak peaks corresponding
to recoiled Ne 6 + to Ne7+ ions. These results suggest that projectile ions have to penetrate deeper
into target atoms when the projectiles are ionized (loss ionization).
Up to now, no theoretical treatment has beenreported of multiple ionization of target atoms
accompanied with simultaneous ionization ofprojectiles in collisions of partially ionized projectiles with neutral atoms which can be compared with the present observations. However, thepresent results can be understood qualitatively
as follows: Projectile ions have to come into
close collisions with target atoms in order to behighly ionized and, in turn, these close collisions
result in higher ionization of target atoms. In
particular if the ionization of the inner-shellH. Tawara, et al.

electrons would occur, followed by cascading of
the inner-shell vacancies toward outer shells, therecoil ions could have much higher charge after
collision.
In collisions of partially ionized projectiles, incontrast to collisions involving innershell electron transfer, simultaneous ionization of bothcollision partners should result in different consequences in their charge distributions. In suchcases, both particles should penetrate each otherdeep enough to be highly ionized and then resultin the production of recoil ions with higher
charge.
In order to fully understand such a multiple
ionization of recoil target atoms, further accumulation is required of experimental data similar tothe present work. At the same time, it would beof great help to theoretically investigate related
topics such as the impact parameter dependenceof multiple ionization processes of target atoms

67

simultaneously accompanied by projectile ionization or electron capture as well as that in pureionization without any change of projectile
charge.
References
1) T.J. Gray, c.L. Cocke, and E. Justiniano: Phys. Rev.

A, 22, 849 (1980).
2) S. Kelbch, J. Ullrich, R. Mann, P. Richard, and H.
Schmidt-Bocking: ]. Phys. B, 18, 323 (1985).
3) M. Horbatsch:]. Phys. B, 19, L193 (1986); M. Horbatsch: Z. Phys. D, 1, 337 (1986); M. Horbatsch and R.M.
Dreizler: Z. Phys. D, 2, 183 (1986).
4) ]. Ullrich, K. Bethge, S. Kelbch, W. Schadt, H.
Schmidt-Bocking, and K.E. Stiebing: I Phys. B, 19,448 (1986).
5) T. Tonuma, T. Matsuo, H. Kumagai, S.H. Be, and H.
Tawara: RIKEN Acce!. Prog. Rep., 21, 84 (1987).
6) T. Tonuma, T. Matsuo, M. Kase, T. Kambara, H.
Kumagai, S.H. Be, 1. Kohno, and H. Tawara: Phys.
Rev. A, 36, 1941 (1987).

68
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-15.

K-LL Auger Spectra of Nitrogen Projectiles

Y. Kanai, T. Kan1bara, Y. Awaya, B. Sulik, *N. Stolterioht,** and Y. Yamazaki

In this report, we present the result from thefirst measurements on high resolution K Auger
electrons from the Be-like nitrogen using themethod of zero-degree Auger spectroscopy which
has been developed by N. Stolterfoht andcoworkers. I) By using this method, we can do thehigh resolution measurement of the ejected electrons from the high velocity projectiles. I )Comparing the results of the high resolution
measurement with a result of theoretical studies,
we can test electron correlation and relativistic
interactions in the projectile ions.
This experiment was performed at RILAC.
Projectiles of 1.33 MeV l u N2+ were magneticallyanalyzed and directed into a He gas cell. Emitted
electrons were analyzed by a zero-degree Auger
spectroscopy apparatus which consists of two

1400

consecutive 900 parallel-plate electrostatic analyzers. It had been temporarily transported fromthe Hahn-Meitner-Institut, Berlin.
Results are shown in Fig.!. Most of the strong
Auger lines in Fig. 1 originate from Be-like initial configurations which were produced by the'needle ionization (selective inner-shell ionization) , in collisions with He. Most of the prominent Auger peaks were fitted by the Gaussian
curve. Energies of the emitted electrons in the
projectile rest frame are listed in Table l. In
consideration of the uncertainties of the projectile energy and analyzing voltage of the electron
analyzer, absolute values of emitted electronenergies were determined with uncertainty of
about ± 0.5 eV. The initial and final states ofeach Auger electron were determined from theN 2 +(1.33 MeV/u) + He

K-LL Auger

Mo..

1200

0N

N

...
s::

-

1000

:J

~
"as

.,

"".,

II)

Mo..
_0..

;0

0..

800
til

600
",,-

aJ
~

.

'"

N

400

--

~.,

",,0..

~

M

'"
'"

-'" -:;:

N

N

N

--'"

N

-

""0..
.,
N

III

., III

N

0N

ono..

N

- .,

0..

~

N

V)

.,

N
_

N

~

N
N

0..

0.. N
on "".,

0..
N

cR
tll

on

N

0..
<I)

N
<I)

-

M

""

<I)

N

-- 0..

<I)

N

<I)

a>

""«

00

III

III

200

315

320

325

330

ELECfRON ENERGY

335

340

345

(eV)

Fig. 1. K Auger spectra from 1.33 MeV l u N2+ projectiles colliding with He atoms. Electronenergies have been transformed to the projectile rest frame. Initial configurations are indicatedon the peaks.
* Institute of Nuclear Research of the Hungarian Acad-emy of Sciences (A TOMKO, Debrecen, Hungary.
** Hahn-Meitner-Institut, Berlin, F. R. Germany.

69

Y. Kanai, et ai.
Table 1. Auger transition energies.
This result(eV)

Initial state

Al
A2
Bl
B2
B3
A3
A4
B4

313.3±0.5315.8±0.5322.8±0.5324.9±0.5
326.6±0.5328.2±0.5331.1 ±0.5332.8±0.5Is2s 2Is2s2pIs2s22pIs2s2p2Is2s22pIs2s2pls2p2Is2s22p2D
3pB5

333.3±0.5Is2s2p2

3p

B6
B7
C1
B8

334.9±0.5336.2±0.5
337.4 ±0.5Is2s2p2Is2s22pIs2s 22p2
Is2p3

sp
Ip
2p

Is22p
Is 22ssS

Is2s2p2

3D

Is 22pIs22s

B9340.2±0.5343.2±0.5

Theory(eV)Final state
2S
4p
3p
sp
Ip
2p

Is2

IS

Is2
Is22p
Is22p
Is 22p

IS
2p
2p
2p

Is2

IS
IS
2S
2p

ls 2
Is 22sIs22p

Is22p2

2S
2S
3p
2p
2S

312.16315.2 6323.36 b
324.76 b
326.99 b
328.06331.7 6333.45 b
333.21 b
334.84 b
337.08 b
339.88 b
344.41 b

a, Ref. 3; b, Ref. 2.

comparison with theories 2• 3 ) and a systematic
study of Auger spectra of oxygen projectiles. 4 )References
1) N. Stolterfoht: Phys. Rep., 146, 315 (1987).
2) M.H. Chen: Phys. Rev. A, 31, 1449 (1985).

3) R. Mann, F. Folkmann, and H .F . Beyer: ]. Phys. B,
14, 1161 (1981).
4) R. Bruch, N. Stolterfoht, S. Datz, P.D. Miller, P.L.
Pepmiller, Y. Yamazaki, H.F. Krause, J.K. Swenson,
K.T. Chung, and B.F. Davis: Phys. Rev. A, 35, 4114
(1987) .

70

RIKEN Accel. Prog. Rep. 22 (1988)

111-2-16.

Analysis of the Mg IX 2s3d-2s4f Transitionof Beam-Foil Spectra

K. Ando, S. Kohmoto, Y. Awaya, T. Tonuma, and S. Tsurubuchi
Be-like ions have a simple electron configuration, but their energy levels have been known
only below the principal quantum number (n) of
3. Above n = 4, energies of terms have not fully
been analyzed, and the wavelength region
around few hundred Angstrom, which occurs
mainly from the transitions from n = 4 to 3, isblank in wavelength tables. But this wavelength
region is important in the experiments on highdensity plasmas.
The transition array of 2s3d-2s4f has been
identified for Be I to F IV, for Al X ,and for Si
XI. For latter two elements, however, only 3d
3D- 4f 3F lines have been identified.
A problem in the identification of the singlet
transition is that this transition array is overlapped with another transition array of 2p3d2p4f as shown in theoretical spectra calculated.0.0.

20.4.0.0.

20.8.0.0.

2,12 . 0..0

2.16.0.,0.

by the multiconfiguration Dirac-Fock. Also, the2s4f configuration has a configuration interaction with the 2p3d as described by Edlen. 1 ) We
analyzed the 2s4f configuration, taking into
account the configuration interactions. The
lower levels of 2s3d have been already known
and their energies were obtained from theGrotorian Diagram of Mg IX. 2)
Spectra of magnesium ions were measured forthe beam energies of 12, 19, and 32 MeV fromthe RILAC with a 2.2 m grazing incidence
spectrometer (McPherson 247) with a grating of
600 grooves/ mm. The entrance and exit slit
widths were set for sufficient resolution. The
wavelengths of spectra were calibrated by using
known spectral lines of magnesium ions.
An isoelectronic sequence of the 2s3d- 2s4f
transition was obtained from the data of C III to
2.20. . 0.,0.

2.2 4.0.,0.

228.0.,0.

2,3 2.0..02,3 6.0..0

2 ,40..0.,0

2.44

u..
CO)

~

u..

C\I

-

en
I

~

0

en

CO)

C\I

I

0

f"'I~1.t"\ O~ctl~~"IIt--nt\,ft()\OC'\IOM OI""'l(Z) C:CO\O\CC'D-t\JC)
c:>nOQ) ,..."r-,O\ """-QO'III'q)'III'C'\J'ooC

rV~~ vWl~~ c:C~~--:~~~"";~";~~~"':"":cD~~

O\OO\Qr"l t"')c:o~

000000000

0000_______ --------

0\. '0'"\OG)-~'C ... Ot'""I-O\\OOO\O\O"""IIa"(\J"""-\O

CCOOO"CC~~o CZ)t'\,rCZ)~-\OC'""\o\~O'\~Q)Il"I-"'" ~~4""I0\""''':fC'\,jO\\O-.t\0":~ro;~.,;..:v;~~"":"":~OO-=NN~";";
t\Jf\J (\,Jt'\J~~t\J~t""Ir,,...,~~~~~~ ;;~"'~t\JC\I<V\j~""""''''''''''''''''''''''''''''''''''''''''''<\I<\I~''''''<\I''''''''''''''<\I''''''<\I'''''''''"""<\1<\1<\1<\1"""""

Fig. 1. A spectrum of Mg ions obtained in the beam-foil experiment using 19 MeV, in which newly identified
transitions of 2s3d-2s4f are indicated. Numbers appearing in the bottom are uncalibrated wavelengths, which
are different about -1. 5 A from the real wavelength, and the cross marks show the observed intensities.

71

K. Ando, et al.

Table 1. Observed lines of the 2s3d- 2s4f transition in Mg IX.
Wavelength

Intensity
960
170

(A)

Wavenumber(cm- I)

Combination

218.45229.07457,770
436,5502s3d 3D I,2,3 - 2s4f 3F 2,3,4
2s3d ID2 -2s4f IF3

Table 2. Energy parameters (cm -I) .
Configuration
2s4f

Parameter

Fitted value

H·F Value

Fit/ H-F

2,085,141
3,285

2,051,485
4,266

GI (2p,3d)G3 (2p,3d)
S-(2p)
S-(3d)

15
1,808,032
73,69762,65432,766
2,179
107

15
1,766,807
68,47564,32137,3522,582
107

1. 0160.770
1. 000*RI (sf, pd)
R 2(sf,dp)- 95,502- 9,302-50,657- 14,435

Eav
G3 (2s, 4f)
S"(4f)

2p3d

Eav
F2 (2p,3d)

1.023
1.076
0.974
0.877
0.844
1. 000*Configuration interaction
1.885
0.644

*S- (4f) and S- (3d) were not varied in the least squares fitting, because these values were too small.

F VI, Al X, and Si XI. 2.3) The wavelength of thetriplet transition 2s3d 3D-2s4f 3F was estimatedfrom the isoelectronic sequence. From theseresults, the strong line observed at 218.45 A was
identified as the transition of 2s3d 3D I.2.3-2s4f
3F2.3.4 •After determination of the 3F levels, theparameters of energy expressions for the 2s4f
and 2p3d configurations, which included theconfiguration interaction mentioned above,were fitted by the least squares method. 4-6) The. parameters used are average energies, Slater
direct- and exchange-radial integrals (Fk, Gk) ,spin-orbit interactions(~) for the 2s4f and 2p3d
configuration, respectively, and configurationinteraction-radial integrals (Rk) between thetwo configurations. The initial values of theseparameters were calculated by using the
Hartree-Fock program code of MCHF77. 7) Fromthe least squares fitting, the energy of the IF
state are obtained, and the wavelength of thetransition of 2s3d ID- 2s4f IF was estimated_ An
isolated spectral line was found near this estimated wavelength, and was identified as the
singlet transition of 2s3d ID-2s4f IF.
The observed spectrum is shown in Fig. 1,
where the identified lines are indica ted _ The
result of identification and classification are
given in Table 1.
The parameters are determined from the ob-served energy levels by means of the leastsquares fits. 7) Table 2 shows the fitting values,
the Hartree-Fock values, and the ratio of fitted
value to Hartree-Fock for each parameter. The
designation of energy levels of 2s4f and 2p3d
configurations are determined. The standard
deviation of fitting energies is 695 cm- I for ·13
experimental levels of the 2s4f and 2p3d configurations. The differences between the experimental and fitted level energies are small for thelevels of 2s4f, but are slightly large for 2p3d,
especially for 3p levels. This suggests that the 3p
levels have a configuration interaction withother configurations.
References
1) B. Edlen: Encyclopedia of Physics, Vol.27, SpringerVerlag, Berlin, p.80 (1964).
2) S. Bashkin and ].0. Stoner, Jr.: Atomic Energy Levels
and Grotorian Diagrams, Vol. 1, North-Holland Pub.
Co., Amsterdam (1975).
3) RL. Kelly:]. Phys. Chem. Ref Data, 16 (Supplement)
No.1, p. 1 (1987).
4) RD. Cowan: Phys. Rev., 163, 54 (1963).
5) RD. Cowan and D.C. Griffin:]. Opt. Soc. Am., 66,
1010 (1976).
6) RD. Cowan: The Theory of Atomic Structure andAtomic Spectra, Univ. California Press, California(1981).
7) C.F. Fischer: Comput. Phys. Commun., 14, 145 (1978).

72
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-17.

Impact Parameter Dependence of Ne K-X Ray Emission in
10 MeV Ne 7 + on Ne Collisions

T. Kambara, Y. Awaya, Y. Kanai, H. Schmidt-Backing, and H. Vogt

The excitation mechanism of inner-shell electrons in heavy ion-atom collisions is often described as direct Coulomb or molecular orbital
processes which are based on the interaction
between the excited electron and the timedependent nuclear field during the collision.
However, in some cases, the interaction between
the excited electron and one of the electrons of
the collision partner can be important in the
excitation process. The electron-electron correlation effect, which is known as resonant excitation and transfer (RTE),l) is expected to show up
in the K-X-ray-emission probability P(b, 4» in a
specific outgoing charge state, where b is theimpact parameter and ¢> is the angle between the
scattering plane and the X-ray emission direction.
In order to investigate the different excitation
mechanisms, we have started to measure P(b, 4»
for different outgoing charge states in Ne-Ne
collision systems. At first, we measured the twodimensional angular dependence of 10 MeV Ne7+
projectiles colliding with Ne for the outgoing
charge states from Ne4+ to Ne7+ in coincidencewith the Ne K-X rays. In this collision energy,
the K-shell excitation is dominated by the 2pO"2pn rotational coupling.
The experimental setup is shown in Fig. 1. A
Ne7+ beam from the RILAC was collimated by apair of slits, passed a Ne gas target, and wascharge-state analyzed by a magnetic deflectionof 25° and detected by a two-dimensional
position-sensitive gas detector (PP AD) with a"wedge and strip" anode 6 m after the target.

240

."

"

,

180

'"
X

10

>- 60

• '0' ·!:; .:,,: ~. :. ,', .. ' .

..

'

.:

(a)

240 f--,,,::' ,' ": ; :

",

"

:',

,:'

,

o I,.;-O-~~5h'IU"----;1"+dln--U~-'T'1'1~biO:--------;O;d~'40i"l"""X-a x Is(b)

Collimators

MagnetPath without
Scattering
Coincidence
CircuitFig. 1.

Experimental setup.

2-dimensional
PPAC

Fig. 2. Examples of position spectra of scattered Ne
ions with outgoing charge states of 7+ (a) and 4+ (b) incoincidence with Ne K·X rays, 1 em corresponds to 40
channels in each direction, Particles with small scattering angles are blocked with a Faraday cup of 12 mm indiameter. A circular blank in each position spectrum isa shadow of the Faraday cup.

T. Kambara, et al.

The target gas was emitted into a collision
region in a evacuated chamber through a thinnozzle. The target density was so small that asingle-collision condition was fulfilled. The scattering angle for the separated charge state wasdetermined by the position relative to the beam
center. The position resolution is better than 1
mm which corresponds to 1.6 X 10- 4 rad of scattering angle 8. For measurements of large angle
scattering (8) 10- 3 rad), a Faraday cup with adiameter of 12 mm was inserted in front of the
PP AD to block the particles with smaller scattering angle to avoid a too large count rate. The X
rays from the target region were measured by aSi(Li) detector mounted at 90 to the beam direction.
0

73

Examples of the two-dimensional position
spectra of the scattered particles in coincidencewith the Ne K-X rays are shown in Fig. 2. The X
rays were detected in the direction of the X -axis.
The Faraday cup was set in front of the PP AD
which made a circular blank in the spectra. The
experimental results show a outgoing chargestate dependence of the K-excitation probabilities as a function of the scattering angle. Further analysis is in progress.
Reference
1) S. Reusch, P.R. Mokler, T. Kambara, R. Schuch, G.

Wintermeyer, A. MUller, Z. Stachura, and A.
Warczak : This Report, p. 57.

74
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-18.

K Auger Spectra of Doubly-Excited Helium-Li ke Carbon

H. Sakaue, K. Ohta, T. Inaba, * Y. Kanai, S. Ohtani, K. Wakiya,
H. Suzuki, T. Takayanagi, T. Kambara, and Y. Awaya

We started studies of ion-atom collisions byusing highly ionized ions from the RIKEN ECRIS(electron cyclotron resonance ion source) which
was constructed for the A VF cyclotron. In thisreport, we present the result of the first measurements of K Auger electrons of doubly-excited
He-like carbon using 5.0 ke V lu 13C6+ projectiles
in collisions with He. The 13C6+ projectiles weremade by the ECRIS. Projectiles were analyzed
by a 90° analyzing magnet and then collided withtarget He in a gas cell. Doubly-excited He-likecarbon ions were produced by the doubleelectron capture from target He atoms. Electrons were measured at the observation angle of
0° with respect to the beam direction by an electron spectrometer. It consists of a 90° parallelplate electrostatic analyzer and a simulated
hemispherical electrostatic analyzer; the former
was used to steer the electrons out of the ion
beam and the latter determines the electronenergy resolution. Results are shown in Fig. 1.
Under a single-collision condition, we observed
Auger electrons whose initial-state configurations were (2l nl'), where land l' are angularmomenta and n principal quantum number(n~3) .

When the target pressure was high, we observed spectra like the lower one of Fig. 1. Twogroups of peaks below 300 eV correspond to thetransitions arising from the Li-like carbon,
which were made by double collisions. The
spectroscopic studies of K-Auger electrons fromthe Li-like carbon were made completely by R.
Mann. I) All peaks below 300 e V can be identified
as the same as those reported by R. Mann. The
lower group is attributed to the decay of the (Is* Institute for Laser Science. University of Electro-

Communications.

13 C 6+ + He

n=3

2

;

~
=4n=5

1

n=6

-e O~IIIo'..Ioo.v,.tIU................~'"
1s 2.l n J'......................'--1

n=2

250

300

350

ELEcrRON ENERGY ( eV

Fig. 1 Auger electron spectra for 13C6 + on He gas.
Upper spectrum are under single collision condition.
Lower one under double collision condition. Initialstate configuration before Auger decay is indicated oneach group of peaks. Auger electrons peaks from the(21 2l') configuration are expected around 270 e V .
2l 21') state and upper one to the (Is 2l 3l').

Using these peak positions, we calibrated ouranalyzer.
Under the single-collision condition, we observed spectra like the upper one of Fig. 1. We
can identify each group of peaks as shown in the
figure. There are two features of this spectrum:(I) no peaks of (2l 2l') configurations (around
270 eV) and (2) peaks of (2l nl') configurations
can be observed in a wide range of n (n~3).
Precise analysis of the results is in progress.
Reference
1) R. Mann: Phys. Rev. A, 35, 4988 (1987).

75
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-19. Observation of the Velocity Distribution of a Sodium
Atomic Beam Irradiated by a Resonant CW Dye Laser
T. Suzuki, * T. Minowa, and H. Katsuragawa
We have reported two-step photoionization ofa sodium atomic beam using cw and pulsed dyelasers. 1) The dependence of the signal intensity ofthe two-step photoionization upon the power ofthe radiation of the cw dye laser suggested thatlaser cooling of the sodium atomic beam took
place. To ascertain this conclusion, we haveundertaken to investigate the change in thevelocity distribution of a sodium atomic beamirradiated with a resonant laser.
The experimental set up is schematicallyshown in Fig. 1. The distance between a sodium
atomic beam source and an ionization region
was 22 cm. Sodium atoms take about 0.2 ms toarrive at the ionization region because the mean
velocity of a sodium atomic beam is about 10 3 m/s. During this flight time, sodium atoms interact
with a counter-propagating resonant cw laser
radiation, which has been tuned to the 3P l/2-3S 1/2
transition of sodium, and are pressed with theradiation toward the beam source.
In the ionization region, sodium atoms were
ionized by the radiation of the cw laser and of
the pulsed dye laser (wavelength 390 nm). The
pulsed dye laser beam was focused with aconverging lens (focal length 10 cm) . Resultant
sodium ions flew freely in a stainless-steel duct

(3 cm in diameter). The duct had a hole (5 mm indiameter) at the end, through which ions were
pulled out toward a CERATRON detector. The
duct shielded the electric field around the detector which was formed by a bias voltage (3.5 kV)
to the detector, thus the velocity change of ionshaving been minimized. Since the distance
between the ionization region and the hole was
20 cm, the TOF of sodium ions was estimated at
0.2 ms from the mean velocity of sodium atoms;
the estimated value was close to the observedone.
The output signals from the CERA TRON
detector were fed to a transient recorder triggered with the pulsed dye laser. The time 'difference
between the triggering and the signal acquisition
was recorded in a TOF spectrum by a computer.
The velocity distribution was obtained from the
TOF spectrum and the distance between theionization region and the entrance hole.
Figure 2 shows the TOF spectra. In Fig. 2 (A)

10
10 mW

~
z

;:>

~-------;

cw DYE lASER

~

I:t:;

.'5
><

E-<

H

Ul
Z
~

E-<
Z
H
~

o<l;

z
~

20
50 mW

Ul

10

----+-- A'lQ1IC BEAM ~oFig. 1.

Schematic diagram of the experimental set up.

* Department of Physics, Faculty of Science, Toho
University.

0.5

1.0

TIME OF FLIGHT (ms)Fig. 2. Time-of·flight spectra. (A) the power of aresonant cw dye laser was kept at 10 m Wand (B) at
50 mW.

76

T. Suzuki, et al.

the power of the cw dye laser was kept at 10 mW,
and in Fig. 2 (B) at 50 m W. The two spectra
show marked differences that the width of thespectrum at 50 mW is narrower than that at 10mW and that the peak at 50 mW shifts toward
the time origin compared with that at 10 m W.
The present results are puzzling to us. The line
width of the cw laser was broad; much broader
than the Doppler width of the sodium atomic
beam. To explain the experimental results weassume that all sodium atoms are under a equal
light pressure regardless of their velocities.
In Fig. 3 the calculated result is shown for thechange in the velocity distribution (at 800 K);
line I is the initial Boltzmann distribution givenbyI(v) =Aov 2oexp(- (V /VO)2)(1)

where A is a normalization constant and Vo is themean velocity of a sodium atomic beam.
The velocity at the ionization region of a
sodium atom under one-dimensional pressurecaused by the cw laser is given by
VI = Jv2-2LPo/ M(2)where V is the velocity at the source, L is the
distance between the source and the ionization
region (22 cm) , M is the mass of a sodium atom,
and Po is the light pressure exerted upon sodium
atoms under the resonant condition. Substituting
VI into Eq. 1 and dividing by a expansion factor
F (v) , the velocity distribution at the ionization
region is given byg (VI) =A ° (VI 2 + K) °exp (- (vI 2 + K) / v0 2) / F(v)(3)

where K is 2 LPo/ M. The expansion factor

1.0

gj 0.5
.0:

0.0

0.5

1.0

1.5

VELOCITY (REL. UNIT)

Fig. 3. Velocity distribution of a sodium atomic beam,I, the initial Boltzmann distribution at 800 K, II, acalculated distribution of a sodium atomic beam subjected to a light pressure.

F (v) is obtained by
dV I = F ( v) ° dv
From Eq. 2 we findF(v) =v/ Jv 2 -K
thus we get

(4)
(5)

g(vl)=Aovl !v 12 +K exp (- (V 12 +K) / v0 2 ) (6)Line II was calculated by Eq. 6 for K = 0.36.
Line II is broader than I, and the peak shifts
slightly toward the lower velocities. This results,
however, are not in agreement with the present
experimental results.
oReference
1) T. Minowa, H. Katsuragawa, and M. Shimazu:
RIKEN Accel. Prog. Rep. , 21, 178 (1987).

77
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-20.

Resonance Ionization Spectroscopy of Lantanoid Elements

H. Maeda, Y. Mizugai, Y. Matsumoto, A. Suzuki, and M. Takami

In recent years there is much interest in laser
application to nuclear physics, in particular inmeasurements of nuclear spins and mUltipoles ofshort -lived nuclei by spectroscopic means. 1)
These physical properties, which provide animportant clue for the structural study of nuclei
far from stability, manifest themselves as hyperfine structures and isotope shifts in electronictransitions of relevant atoms. For such measurement, resonance ionization spectroscopy is ofparticular importance since its ultra-high sensitivity is crucial for high resolution hyperfine
spectroscopy with a small number of atoms
produced by nuclear reactions.
The present work was undertaken with the
purpose of supplying spectroscopic data for thelaser spectroscopic study of short-lived nuclei
provided by RIKEN Ring Cyclotron. Two pulsed
dye lasers, pumped by a XeCI excimer laser,
were used to ionize target free atoms selectively.
The Lantanoid elements were chosen for thetarget since all the elements can be ionizedresonantly with the two pulsed dye laser beams.
As a first stage of such work, ionization spectra
were recorded by setting one of the laser frequencies to an intermediate state and scanning
the other over auto-ionizing or high Rydberg

states which were subsequently field-ionized. A
piece of metal sample was placed in a small Ta
crucible and heated up to 1,800 K to form an
atomic beam. The atoms were ionized under a
0-4 k V / cm electric field with two laser beams.
The produced ions were accelerated and detectedwith a Ceratron ion detector. The ion current
was measured and averaged with a Boxcar Integrator. The laser wavelength was measured by
optogalvanic signals in Ne discharge and interference fringes of a solid etalon for interpolation. A schematic diagram of the experimental
arrangement is shown in Fig. 1.
After preliminary ionization experiments inseveral metal elements, extensive ionization
spectra were recorded for Lu. The relevantenergy level diagram is shown in Fig. 2. The
ground state electronic configuration of Lu is 4f14
5d6s 2 • Since the 4f electrons are tightly bound,
all the configurations below the ionizationenergy (43,762 em-I) are formed only by excitedsta tes of the three 5d6s 2 electrons. Neverthelessthe electronic level structure of Lu I is very
complica ted owing to the existence of many
terms and interactions among them. As a conseJ=3 - - - - - 57961 crn- 1
5d6s 3D 2
56198
55559
1

Autolonlz lng
Rydberg serle
6s2 1 S43762 crn- 1
J=O --=:!!!~~-~--------

DO

5d6s6p FO

Lu II----"'l--30489
29608==;t===29487-~---28020

Oven

5d6s 2
2D J = 5 / 2 - - - 4 - T - - 3 / 2 - - - L -_ _evenFig. 1. Schematic diagram for resonance ionization
spectroscopy.

.Fig. 2.

---IO~_______

odd

Energy level diagram of Lu I.

Lu I

78

H. Maeda, et ai.

E(cm-1)
6s 21 5o ~L,3762

scrnned 29608
Fixed

5d6s6p 20312

5d6s12 03/2>"(nm)

712

710

~1

I . P.

Electric Field
2 kV/cmo043762 cm- 1

708

Fig. 3. Rydberg series converging to the first ionization limit of Lu.

quence the energy levels around the first ionization limit is not well analyzed in spite that thelower electronic states are relatively wellunderstood 2 ) among Lantanoid elements.
Figure 3 shows a Rydberg series, 6s 2 ns and2
6s nd, converging to the first ionization limit.
By changing the intermediate state, three even
Rydberg series (6s 2 ns, 6s 2 nd, 6s 2 ng) were measured. The series show no clear local perturbation and are identified for n up to 80. Figure 4
shows a forced ionization spectrum under anelectric field of 2 k V / cm. Rydberg a toms arevery sensitive to an external electric field, which
substantially lowers an apparent ionization limit
under strong electric field. An interesting feature observed in this spectrum is a very strong
signal observed in the forced ionization continuum. Since this signal was observed only whenthe electric field was strong enough to bring
down the ionization limit below this line, we
concluded that the signal was due to a doublyexcited odd state which located accidentally
among the even Rydberg series, and could beionized only when it gained oscillator strength by

I

43600

43~00

cm-

1

Fig. 4. Forced ionization spectrum of Lu 1. The
electric field is 2 kV f cm. The intermediate state is
the same as in Fig. 3. The ionization limit at zero
electric field is 43762 cm- 1 •Stark mixing with the nearby even Rydberg
states. Under a weak electric field, the intensity
distribution of the nearby even Rydberg series
showed the Fano profile 3 ) by the interference oftransition matrix elements to the doubly-excitedstate and the Stark continuum. Similarly
autoionizing Rydberg series converging to the
5d6s core excited states were observed. Further
analysis and extension of the work to other
Lantanoid elements are in progress.
References
1) See, for example, P. Jaquinot and R. Klapisch: Rep.

Prog. Phys., 42, 773 (1979).
2) ].F. Wyart: Phys. Scr., 18, 87 (1978).
3) U. Fano: Phys. R ev., 124, 1866 (1961).

79
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-21.

Incident Angle Dependence of AI-LVV Auger Spectra
for Ar 12 + Impact
A. Koyama, H. Ishikawa, and Y. Sasa

In a previous report,I) we showed the ZIdependence for energies of AI-LVV Auger peaks
for glancing angle incidence of projectiles; withincreasing ZI, the energy of the Auger peakdecreased. We also showed that the energy
decrease was not due to the Doppler effect of
sputtered Al atoms. 1)
In the present report, we show the incidentangle dependence of the energy of the AI-LVV
Auger peak for ArI2+ impact, and interpret the
ZI - and incident-angle dependence in terms ofshort-lived decresase in density of valence electrons of Al due to the emission of large amountsof secondary electrons induced by glancing angle
incident heavy ion impact.
Experimental conditions are the same as thosein the previous report. 1) Incident energies of Ar I2 +are equal to 1. 3 MeV / amu. Electrons are measured at the normal angle to the surface of targets. Al is in-situ deposited on polished Mo substrates. The flattness of the target is within therange of 1 J.l m ups and downs per 1 mm in length.
Energies of electrons are measured from 1 to 150
eV.
Figure 1 shows the incident-angle dependenceof the energy of AI-LVV Auger peaks for ArI2+
and electron impact. For the electron impact nodependence on incident -angle can be seen; however, for the ArI2+ impact a pronounced dependence is seen. For large angle incidence, theenergy decrease is rather steep, but almost
leveled off as the incidence angles become verysmall. From extrapolation, we estimate the0----- -------0e-

1
sin 8

Fig. 1. Incident angle-dependence of energies of AlLVV Auger peaks for Ar I2 + and electron impact. Incident energy of Ar 12 + corresponds to 1. 3 MeV / amu, andthat of electrons to 1 keY.

energy of the Auger peak for normal incidence of
ArI2+ to be 63.7 eV, and also that for an extreme
glancing angle to be 62.7 eV. In Table 1 theenergetical values of Auger peaks for different
projectiles are tabulated at an incident angle of4°, with the estimated values for 90 and W, andwith differences in these values from that forelectron impact, L1 E .
N ow we discuss the mechanism responsible for
the ZI- and incident angle-dependence; the dependence is caused by the decrease in the density ofvalence electrons, which will be decreased whena large amount of secondary electrons are emitted, although the lifetime of such density
decrease should be short. It is known that thetime for relaxation or polarization of valence0

Table 1. Energies of AI-LVV Auger peaks for various projectiles forincident angle of 40, with energetical values at 90 0 and 0° for Ar 12 + impact
estimated from Fig. I, and with differences in the values from that forelectron impact, t;:.E.
EA (eV)
Zl

8=4°
e
N6+
Ar 12 +
Xe 9 +

63 .9
63.6
62.8
60.9

Estimated EA (eV)
0
0
8=90
8=0

63.7

62.7

t;:.E (eV)
8=40

8=90°

8=0

0.3
1.1
3.0

0.2

1.2

0

80

A. Koyama, et al.

electrons is very short (of the order of plasmon
lifetime, nearly 10- 16 s). It should be noted thatthe lifetime of the decrease in the density ofvalence electrons will be longer than that ofplasmon damping; the time of real transportationof electron-holes from the surface region is concerned, not the time for porlalization of valence
electrons.
Energies of AI-LVV Auger electrons are givenby
E = EB (L) - EB ( V 1 ) - EB ( V2 ) - C + R ,(1)

where EB(v) is the binding energy of L or valence
electrons, C is the correlation energy of local
two electron-holes in an outer shell of the Al
lattice atom concerned, and R is the relaxationenergy. It is known that, when there areelectron-holes in localized outer shells of theatom concerned together with an inner hole, E isdecreased; energies of satellite lines of Auger
electrons are usually lower than that of a diagonal one. The number of holes in the localized
outer shell is an important factor to the decreasein E. However in the case of delocalized outershells, a density of holes around the lattice atom
concerned is important. EB(L) and E B ( V) are
increased, and R is decreased with the increaseof the density of valence electron-holes. After all,E will be decreased with increasing density ofthe electrons-holes as seen in the usual satellite
lines. The density of electron-holes is increased

proportionally with the yields of secondary electrons, that is, E will be decreased as yields of
secondary electrons become high. This is thequalitative explanation for the zl-dependence ofE.
Next we discuss the incident-angle dependenceof E.
For very low angle incidence, the length of theregion in which electron-holes are produced
becomes very large. Thus the components ofvelocities of the electron-holes effective to themigration of them from the region are those
perpendicular to the long axis of the region. On
the other hand, for normal incidence, three components are all effective. Therefore the lifetimeof the electron holes for small angle incidence-dg) becomes longer than that for normal angle
incidence, 'z-(n). Accordingly the decrease in E
for normal incidence will be less pronounced
than that for glancing angle incidence. As theincident angle becomes very low, the lifetime ofthe electron-holes will become long and nearly
T(g); that is, saturation will occur. This is the
explanation for the incident-angle dependence ofE.

Reference
1) A. Koyama, H. Ishikawa, and Y. Sasa: RIKEN Aeee!.
Prog. ReP., 21, 89 (1987); A. Koyama, H. Ishikawa,and Y. Sasa: Nucl. Instrum. Methods B, 33, 308 (1988).

81
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-22.

Excitation of Convoy-Like Electrons by Glancing-Angle Incident
Heavy-Ion Impact
A. Koyama, H. Ishikawa, and Y. Sasa

We measured energy spectra of the electrons
emitted from a thick Al target for the impact ofglancing-angle incident fast heavy ions, N2+.
N7+, Ar H , and Ar12+. with energy corresponding to 1. 27 MeV / amu at detection angles from 1°
to 30° with respect to the incident beam direction.
The experimental setup is the same as described in a previous report. 1) The energy ana1yzer used is an angle resolved one with angle
resolution of 10. Targets are made by in-situ
vacuum evaporation of Al on Mo or Si substrates
with flatness better than 1,um ups and downs per
1 mm length.
Figure 1 shows the energy spectrum of theelectrons excited by N 2 + incident at an angle of
0.5° and detected at an angle of 1.5° from thesurface of the target. For reference the energy
spectrum is also shown of usual convoy electrons

N2+ - Al_~~
Otn=O.5° - --- . .
§
Z

~

=2°

= 17"

o
Electron Energy (e V)

Fig. 2. Energy spectra of the electrons from Al forvarious emission angles induced by N2+ ions with anincident angle of 0.5°. Each angle is given with respect
to the surface of the target.

8'n 0.5'
8emi 1. 5°

N2 +

N2+

e-

8:r?--:: ::::::r;e:,oElectron Energy (e V)

Fig. 1. Energy spectrum of the electrons from Al induced by glancing angle incident N2 + ions, for an incident angle 0 .5° and an emission angle 1.5° relative tothe surface of the target. For reference a spectrum isalso given below for convoy electrons from a C-foil
induced by N7+ ions. Energies of projectiles correspondto l.27 MeV/ amu.

excited from a C foil for the penetration of N7+ .
It is seen that the peak for convoy-like electrons
is also very sharp and the energy of the peak isclose to that of convoy electrons. Figure 2 showsthe energy spectra of electrons induced by 0.5°
incident N2+ and detected at various emission
angles relative to the beam direction. It is seenthat the energy and the width of the peakincrease with the emission angle in the angularrange shown here (angle is given relative to thebeam direction). Figure 3 shows the scatteringangle dependence of the peak energy for various
incident angles; (a) for N2+. (b) for N7+, (c) for
ArH. and (d) for Ar l2+. It is seen that peakenergies are given by a function of the scattering
angle relative to the beam direction; the peakenergy has the same value, only if the scattering
angle relative to the beam direction is the sameand even if the incident angle or the emission
angle relative to the surface of the target isdifferent. For small scattering angles, the peakenergies are higher than that expected fromusual convoy electrons (the expected value is 692

82

A. Koyama, et at.

(a)

900
800

700~-----..
900

(b)

W+-AI
800

~ 700 £~___ __»~ 600L..l....---...l....----'-----J
s::

~

~

Ofn

oOS
• 1.0
02.0
.5.0
t::. 10

0

0

(c)

900

C1)

p.,

ArH - Al::00

~ __ ~_&_2_0_0____~

900
800

(d)
Ar l 2+ - AI~

700~---600 0

10o (degrees)Fig. 3 . Emission-angle dependence of peak energies ofthe electrons induced by projectiles with different incident angles. Incident angles are given with respect tothe surface of the target, and emission angles are given
with respect to the beam direction.

e V in the present case, and is indicated by theline in Fig. 3). The peak energies are highest at
about 5°: 750 e V for N2+ or N7+ , and 800 e V for
Ar4+ or Arl2+ ions. They begin to decrease atangles higher than 5°, and become lower than 692
e V at about 13° for N ions, and at about 20° for
Ar ions. It should be noted that the scatteringangle dependence of these peak energies isalmost the same for N2+ and N7+ , or for Ar4+ andAr l2+ , that is, the peak energies are not dependent on projectiles' charge, but dependent only
on atomic number 2 1 • This charge independence
must be due to the fact that the peak energies are
determined only by close collisions, or that they
are determined mainly after projectile's chargeequilibration.
It is known that for gas targets such an energy
increase has not been observed for convoy electrons excited to the direction slightly different
from the beam direction. Therefore the prominent energy increase ·observed here may be due
to some kind of solid effect. It may be related tothe dynamic surface potential induced by glancing angle incidence of fast high charge projectiles.
Reference
1) A. Koyama, Y. Sasa, and M. Uda:

Prog. Rep. , 18. 86 (1984).

RIKEN A eeel.

83

RIKEN Accel. Prog. Rep. 22 (1988)

111-2-23.

61Ni Mossbauer Studies of Heusler Alloys

T. Okada, Y. Kobayashi, M. Katada, H. Sano, M. Iwamoto, and F. Ambe

In spite of many experimentally undesirable
nuclear properties, 61 Ni can be a powerful probe
in solid-state physics and radiochemistry as asole Mossbauer nuclide other than 57Fe in theiron-group transition elements. About twenty
years ago,we made the first 61Ni Mossbauer
study of the hyperfine magnetic fields on various
Ni-containing oxides with a spinel structure. 1)
This paper reports 61 Ni Mossbauer measurements we started recently on Heusler alloys to
elucidate the physical and chemical state of theNi atoms in these alloys.
A source nuclide 61CU( ~61 N i) was producedby nuclear reactions, 58Ni(a, p)61CU and
58Ni(a, n)61Zn~61Cu. A thin Ni-V(84-16 at%)alloy plate (18 mm x 18 mm XI mm) covered
with 80 ,um Al foil was irradiated for 2 h with
25. 5 MeV a-particles from the cyclotron, andwas used as a source without annealing. The
experimental procedure of the 61Ni Mossbauer
measurements was reported previously. 1) Figure
1 shows the decay scheme of 61Ni. The energy of
the 61Ni Mossbauer y ray is 67.5 keY. It isnessesary to maintain both a source and anabsorber at low temperatures because the Mossbauer transition energy is high and the DebyeWaller factors are low. A cryostat, Model HD700 (Ranger Inc.), was used after slight improve2~1 Ni ( 67.4 keY )
61

61

Cu

Co

- - - - , - --

99m

100%

5 / 2-

ment for cooling both source and absorber down
to liquid-helium and -nitrogen temperatures.
Heusler alloys are a class of concentrated,
ferromagnetic ones of a general composition of
A 2BC. The structure is designated as L2 1, with A
atoms forming a simple cubic matrix and BandC occupying the alternate body centres in the
cubic structure.

~•••••_ ......,'. I';;:; I 00z~,.': •••" I', ••' ••~ \ ,/': ' ..,', ••Wf--~ 99.5
w
>

~ 99
--1

w

0::

-16

-8

0

8

16

RELRTIVE VELOCITY
CNN/S VS METRLLIC NICKEL)

Fig. 2. 61Ni Mossbauer spectrum of RU2NiSn atliquid-nitrogen temperature. The isomer shift isgiven relative to the Ni metal. The curve is theresult of fitting single Lorentzian.

In Fig. 2 is shown the 61Ni Mossbauer spectrumof RU2NiSn above the Curie temperature. Thisis a case of non-magnetic Ni in the matrix.
A typical group of this class of alloys (e.g.
Ni 2MnSn) is known to have magnetic moments
localized on the Ni and Mn atoms at the A and B
sites. In such a system of Ni 2MnC (C is a typicalelement of the group III to V in the periodic
table), the magnetic moment and the electronic
state of the Ni atoms have not been sufficiently
elucidated yet. We are studying the physical andchemical properties of the N i a toms in the system Ni 2MnGe utilyzing the hyperfine magnetic
field and the isomer shift from the 61 Ni Mossbauer spectra.

3/ 2 -

Reference
1) H. Sekizawa, T. Okada, S. Okamoto, and F. Ambe:].

Phys., 32. Cl-326 (1971).

Fig.!.

Decay scheme of 61Ni.

84

RIKEN Accel. Prog. Rep. 22 (1988)

111-2-24.

57Fe Mossbauer Study on Superconductor Oxides

T. Okada, K. Asai, N. Sakai, Y. Sasa, and T. Yamadaya*

In spite of a great deal of endeavor of manygroups worldwide, the origin of Cooper pairingin high- Tc oxide superconductors still remains
unelucidated. A YBa2Cu307-Y oxide, which isso-called a 1-2-3 compound, has a superconducting critical temperature well above 90 K and somuch effort has been devoted to the studies on its
chemical and physical properties. Metallic
dopants directed at Cu sites in this Cu oxide
superconductor are known to systematicallyalter crystalographic, magnetic, and superconducting properties. To understand these changes,
it is crucial to establish the site occupancy andoxygen stoichiometry of the doped materials.
Although some microscopic studies on the electronic structures of this material by using hyperfine techniques have been reported by several
groups including us,I-3) interpretations and conclusions of the experimental results are slightly
different among the groups. In this paper, we
report the 57Fe Mossbauer study on the crystallets YBa2 CU3-X Fe x 07-Y (x = 0.03) aligned along
the c axis by applying a magnetic field. Mossbauer spectra were taken at room temperature
with a conventional driving system, and analyzed with a FACOM780.
The preparation of YBa2Cu3 - xFex07-Y oxides
was described in a previous report.I) Theseoxides obtained with dopant concentrations from
x=0.03 up to x=0.3 were found to be of a single
phase from X-ray diffraction analysis. We try to
elucidate the possible site configulation by establishing for the first time the sign, spatial orientation, and asymmetry parameter 1] = (Vxx - Vyy ) /Vzz of the electric-field-gradient (EFG) tensor. In
Mossbauer measurements on single crystals, theratio of the integrated area in a quadrupole
doublet is no longer unity as it is in polycrystalline specimens. This ratio j- / j + changes withthe angle () as in Eq. 1 when Vzz<O and 1]=0,/- / /+=3 (1+cos 2()) / (2+3 sin 2())(1)
where j- and / + are the integrated areas in the
low and high energy, respectively, and () is the* Faculty of Literature and Science, Yokohama CityU ni versi ty.

angle between the y-ray direction and the principal axis of EFG. The measurements on single
crystal are desired to clarify the site configurations of the Fe ions in the YBa 2Cu 3- x Fe x 07-Y
system. However, there are no single crystals
available containing enriched 57Fe ions. The
measurement was made possible by use of oriented crystallites with y ray transmitted at various tilt angles (if» relative to the aligned axis (caxis). The orientation of YBa Z Cu 30 7- y crystallites along the c axis using the magnetic field
was demonstrated by Farrell, et al. 4 ) using thesame procedure, we have now oriented the
YBa2Cu2.97Feo.0307-Y crystallites and confirmedthat they are orieted along the c axis by meansof an X-ray diffraction measurement.
The two X-ray diffraction patterns of
YBa2Cu2.97Feo.0307-Y oxides are shown in Fig. 1.
The patterns (A) and (B) were measured on thesamples un oriented and oriented along c axis byapplying a magnetic field of 20 kOe, respectively.
These patterns were analyzed by utilizing Sasa's
method 5) in order to obtain the orientation degree
h of crystallites. From the pattern (B) in Fig. 1,
it is clear that the crystallites are oriented alongc axis, and the h is obtained to be 4.0 X 10- 2. It
5 k r--------------,(11 0 )

"at random"~t:g 10 K(006 )

Q(005 )(003 )"oriented"(110)

o ~~~~~~~~~~~~~
20

30

40

50

60

26 (degree)

Fig. 1. X·ray powder patterns of YBa2Cu2.9r
Feo.o307 -Y unoriented (A) and oriented by applying
the magnetic field of 20 kOe (B).

85

T. Okada, et al.

3.0

l.OO~

o

\\ .

2.0

V'J

l.0

- - - - - + -----9+0--~

0.0 0 L - - - - ---f
3 0

60
¢

(degree)Fig. 3. Observed intensity asymmetries 1- / 1+ at
the four sites as a function of the tilt angles </J. The
upper solid line is obtained from Eq. 1 when 8 = </J
and Vzz < O. The lower one is the reversed value of
Eq. 1 when ()=</J and Vzz>O.

2-2
VELOCITY (mm/s)

Fig. 2. 57Fe Mossbauer spectra of the oriented
YBA2Cu2.97Feo.o307-Y measured at room temperature with various tilt angles </J.

means that the sample aligned by applying themagnetic field are almost oriented. Figure 2
shows typical Mossbauer spectra of the oriented
YBazCuz.97Feo.o307-Y crystallites with various
angles if> between the y-ray direction and the caxis. The spectra of the samples comprise atleast four different doublets, a, b, c, and d, withquadrupole splittings of 2.0, 1.6, 1.3, and 0.5
mm/ s, respectively. The observed intensity
asymmetries j - / j+ at the four sites as a func-tion of the tilt angles are shown in Fig. 3. The
values of j- / j+ at the a, b, and c sites are nearlyon the upper solid line when f) = if> and Vzz < 0 .
The values of j- / j+ at the d sites are on thelower one when f)::=if> and Vzz>O.
These results are being subjected to discussion.
References
1) T. Okada, N. Sakai, K. Asai, Y. Toba, and T.
Yamadaya: Hyper/ine Interact ., 42, 1231 (1988).
2) D. McDaneel, W. Huff, B. Goodman, G. Lemon, D.E.
Farrel, and B.S. Chandrasekhar: Phys. Rev. B, 38,
11313 (1988).

3) V. Sedykh, S. Nasu, and F.E. Fujita: Solid State
Commun. , 67, 1063 (1988).
4) D. Farrel, B.S. Chandrasekhar, M.R. McGuire, M.M.
Fang, V.G. Kogan, J.R. Clem, and K. Finnemore:
Phys. Rev. B, 36, 4025 (1987).
5) M.Uda and Y. Sasa: J Solid State Chem., 46, 121(1983).

86
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-25.

Motion of Kr-Bubbles in Krypton-Implanted Aluminum
H. Yamaguchi,* 1. Hashimoto,* E. Yagi, and M. Iwaki

The random motion of some kinds of inert gas
bubbles during isothermal annealing has been
observed by several investegators. Willertz andShewmon studied the motion of the He gas bubbles in Au and Cu foils by measuring the rate ofout-diffusion of the bubbles from the foil surface
and a change in distance between them duringisothermal annealing, and demonstrated that the
diffusion rate of the He bubbles in both foils is
smaller than that predicted by a surface diffusion
model.!) The Brownian motion of He bubbles inV during isothermal annealing at 1,223 K wasinvestigated by in-situ hot stage transmission
electron microscopy (TEM) by Tyler and Goodhew, who concluded that the growth of the bubbles is due to their migration and coalescence. 2 )On the basis of these results, the kinetics ofmotion is explained in terms of either surface
diffusion or ledge nucleation at faceted surfaces,
thus suggesting that the migration mechanism ofinert gas bubbles seems to be dependent on thematerials. In the present study, we investigatedwhich mechanism controls the random motion of
Kr bubbles in Al during annealing.
Aluminum foils of about 130 }.lm in thickness
prepared from an ingot of 99.99% purity by
rolling were used to prepare single crystals bystrain annealing. Thin foil specimens suitable for
TEM were prepared by chemical-and electrolytical-polishing. Kr implantation into the specimens was carried out with 50 ke V Kr+ ions in a
vacuum of 3 x 10- 6 Torr at room temperature toa fluence of 10 16 Kr/ cm 2 by using a RIKEN lowcurrent implanter. In order to specify the position of Kr bubbles in TEM observation, Au
particles were deposited after the implantation
as reference points on both top and bottom surfaces of each specimen by a vacuum deposition
method.
The specimen was mounted with a Cu meshand was observed with an electron microscope
operating at 100 kV. The specimen was thenremoved from the specimen holder and annealed
in a vacuum capsule together with the Cu mesh
* Department of Physics, Faculty of Science, Science

University of Tokyo.

at various fixed temperatures in the range from
573 to 633 K for 10 min. The annealed specimen
was observed again to examine the change in
relative position of Kr bubbles. Micrographs
were taken under the same diffraction condition
before and after each annealing using a tilting
and rotating specimen stage. They indicated thatno growth of Kr bubbles took place during theannealing.
The radii and the centers of about 100 bubbles
selected from a micrograph were determined asfollows. The image contrast of the bubbles
printed on a photographic paper was taken in animage scanner (EPSON, GT-D3000V) as a func tion of the position, and this information wastransferred to a personal computer (PC-9801XL).
The values of the radii and the centers of bubbles
were obtained accurately after making a minor
correction for both magnification and inclinationof the specimen by using either three Au particles
as mentioned above or large bubbles which did
not move during isothermal annealing as reference points. The displacement of a bubble was
detected by measuring a distance between centers of the bubble before and after the annealing.
The accuracy in the measurement of the distancewas estimated at 0.7 nm for a bubble of 2 nm inradius.
Figure 1 shows typical electron micrographs of

Fig. 1. Typical electron micrographs of Kr bubbles;(a) as-implanted and (b) after annealing at 603 K for
10 min.

87

H. Yamaguchi, et al.

Kr bubbles before (a) and after (b) the annealing at 603 K for 10 min, where white and dark
spots correspond to the bubbles and the reference
points of gold particles, respectively. The density
and the radius of bubbles are estimated at 8 X
10 16 / cm 3 and about 2 nm on an average, respectively.

(a)

;

.,

il

~

.,.,

Vi>'-"

Temperature(K)633 603

573

(b)
o

.€j

•
• •

o
o

-16

10 1'=".2-'--"":"1.'-:-4-L...--::'1.'-:-S----'L...--'1.8
1000/ T
( 11 K )•• " •"" • .e•"• "Fig. 3 .

5 nm

e

eo

~

".

e
~·e

eo

"e •

e

(!t>

"

• "
eee

t>
t>

e

e

t>

e
50nm

Fig. 2. Behavior of 114 Kr bubbles indicated bysmall open circles in Fig. 1 on annealing at 603 K
for 10 min; (a) the positions of these bubbles before( 0 ) and after (.) annealing, and (b) the radialdisplacement of these bubbles, in which the magnitude of displacement is shown by the length oflines.

Figure 2 (a) demonstrates the displacement of
bubbles before and after annealing. From thisresult, the distribution of the displacement ofthese bubbles is shown in Fig. 2 (b), in which thecenter of each bubble before the annealing istaken as an origin. The result shows that bubbles
move in all directions during annealing, in
accord with the assumption that bubbles migrate
at random.
The radial moving distance of each bubble, R ,during isothermal annealing for a given time t(Fig. 2 (b)) is the distance projected on the horizontal film plane. In such a two-dimensionallyprojected distribution, the mean square moving
distance is given by(1)
where DB is the diffusion coefficient of bubbles.
From the <R2 ) value observed for each bubble,
DB is calculated. This method has been used by atleast other three investigators under isothermal
conditions. 1- 3 ) Figure 3 shows the relation
between DB and the inverse of annealing temperature 1/ T (indicated by 0 ), together with the
diffusion coefficient D obtained previously fromthe extraction experiment of Kr in Al (indicatedby 6 ).4) It can be seen that InDB versus 1/ T plot

Diffusion coefficients versus 1/ T .

is approximately on an extrapolated line of thatobtained from the extraction experiment of Kr
atoms. 4 ) The activation energy for the motion of
Kr bubbles calculated from the plot in Fig. 3 isl. 50 e V, which coincides with that for selfdiffusion in A1. 5 ) As reported previously, in an
as-implanted state of this specimen Kr bubbles
are in a solid phase epitaxially aligned with thehost Al matrix. 6) The melting point of solid Kr
was estimated at 618 K.6) It should be noted thatvalues of both D and DB fell on the same line
irrespective of the state of Kr bubbles (solid,
liquid, or gas state) (Fig. 3). If the mechanism of
the motion of bubbles changes abruptly at someannealing temperature by reflecting the change
in their state, the values of DB would not be on
the extrapolation line of D versus 1/ T. Therefore, we believe that the motion of Kr bubbles in
Al is controlled by the volume diffusion of Al
atoms over the whole temperature range. Thismeans that the Kr bubbles move at random andreach the surface of the foil specimen to bereleased. More detailed descriptions are given in
Ref. 7.
References
1) L.E. Willertz and P.G. Shewmon: Metall. Trans., 1,2217 (1970).
2) S.K. Tyler and P.J. Goodhew:]. Nucl. Mater. , 92, 201(1980) .
3) M.E. Gulden: ]. Nucl. Mater., 23, 30 (1967).
4) K. Takaishi, T. Kikuchi, K. Furuya, 1. Hashimoto, H.
Yamaguchi, E. Yagi, and M. Iwaki: Phys. Status Solidi
A, 95, 135 (1986).
5) T.S. Lundy and J.F. Murdock:]. Appl. Phys., 33, 1671
(1962) .
6) 1. Hashimoto, H. Yorikawa, H. Mitsuya, H. Yamaguchi, K. Takaishi, T. Kikuchi, K. Furuya, E. Yagi,
and M. Iwaki:]. Nucl. Mater., 149, 69 (1987).
7) H. Yamaguchi, 1. Hashimoto, H. Mitsuya, K. Naka·mura, E. Yagi, and M. Iwaki:]. Nucl. Mater., 161, 164(1989).

88

RIKEN Accel. Prog. Rep. 22 (1988)

111-2-26.

Lattice Location Study on Kr Atoms in Aluminium by
Means of a Channelling Method
E. Vagi

It has been known that the heavier inert gases(Ar, Kr, and Xe) implanted into various fcc
metals precipitate in bubbles into an fcc solid
phase epitaxially with a host matrix. l •2 ) The
evolution and the annealing behaviour of such
precipitates (bubbles) have been investigatedmostly by transmission electron microscopy.3-7)
In the present study the lattice location of Kr
atoms implanted into Al crystals at room temperature was investigated by means of a channelling
method. The lattice location study in such a finescale will give information on the bubble nucleation in an early stage of implantation.
Aluminium single crystals of 99.999% purity
were chemically and electrolytically polished,
and then annealed in a vacuum of 10- 6 Torr at
823 K for 7 h. Kr+ implantation was carried out
at room temperature at 50 ke V at a dose rate of
3.2x10 l2 / cm 2 ·s to two different doses, 4 x 10 14 /cm 2 and 1 x 10 I5 / cm 2 • The channelling angularscan was made with respect to <1 00) , <11 0),
and <Ill ) axes by means of backscattering witha 1. 0 MeV He+ beam accelerated by a tandem
accelerator. The beam was collimated to give adivergence of less than 0.076 The area irradiated was 0.78 mm 2 and the beam current was 1-2
nA. In the angular scan, to minimize the irradiation effect by an analysis-beam, the measurement
was started at an incident angle 'If for the paralFor eachlel incidence to the channel ('If = 0
value of 'If backscattering yields were accumulated up to the irradiation dose of 3 fiC (the<1 0 0) and <110) channels) or 3.3 fiC (the <Ill)channel) for the 4 x 10 l4 Kr / cm 2 implantation, and
0.9 fiC (the <1 0 0) channel) or 1. 2 fiC (the<11 0) , and <Ill) channels) for the 1 x 10 l5 Kr /cm 2 implantation.
Channelling angular profiles for as-implanted
specimens are shown in Fig. 1. As described inprevious papers, 8.9) these results suggest that the
Kr atoms are distributed over random (R) sites,
substitutional (S) sites, tetrahedral (T) and octahedral (0) sites. The distribution of Kr atoms
over these sites was estimated from the fitting of
calculated angular profiles to the observed ones.
The calculation was performed on a basis of a
0

•

o AI

(100)

( 110)

(111)

I

I

I

y

1.0

0

• Kr

0.5

...J

W

>=

0

W

N

::::;
4:

0

L

a:
0
z

( b)

1.0

0.5

0 ~- ~2~0~~~~-~2~~0~72~~--~2~0~~~

ANGLE (deg)Fig. 1. Channelling angular profiles of backscatter·ing yields of He ions from Al and implanted Kr
atoms on the as-implanted specimens for (a) 4 x 10 14
Kr/ cm 2 and 1 x 10 1 5 Kr/ cm 2 implantations. The dotted curves are calculated ones for the distribution
with (a) 30% of Kr atoms at R-sites, 40% at S-sites,
10% at T·sites and 20% at O-sites, and (b) 57% of Kr
atoms at R-sites, 23% at S-sites, 3% at T-sites and
17% at O-sites.

0).

multi-string model.
The observed profiles were well fitted withcalculated ones for a distribution with 30- 32% of
the Kr atoms at R-sites, 40- 42% at S-sites, 8- 10%
at T -sites and 18-20% at O-sites for the 4 x 10 14
Kr/ cm 2 implantation, and with 55-57% at Rsites, 23-25% at S-sites, 3-5% at T-sites and15- 17% at O-sites for the 1 X10 I5 Kr/ cm 2 implantation. Examples of calculated profiles areindicated by the dotted curves in Fig. 1.
The variation of the distribution with implantation dose is shown in Fig. 2(a) together
with the previous result for the 1 x 10 l6 Kr / cm 2
implantation, for which Kr atoms precipitate inbubbles into a solid phase (solid bubbles).7l The
number density of the Kr atoms located at vari-

89

E. Yagi

1.0 .--------.-----.----,----G'--,

(a)

( b)

( a)

•

z

(100)

(111)

j

I

o

~

~ 1.0

l.L

o

~ 0.5
a:

:=i

4:

101 5

1014
xl 014

f

oJ

lJJ
N

OL--L~LW~r_=~==~~~

~

Y
,

>=

§

0.5

OOSE(cm 2)

10~---------~

(b)

<o''E
>

l-

I])

~

5

Cl

a:

0~--~2~0~~2~~-~2~0~~~

•

o • R
o • S
o • 0

~

T

ANGLE(deg)

R

6

•

l

lannealed
593K 30min

as-implan t ed

w

./

OJ

2

::J

Z

o

o

~S

~....I.....-J'---7:--'5

10

x 1014

OOSE(cm 2)

Fig. 2. Dose dependence of the distribution of Kr
atoms. (a) The fraction of Kr atoms located atvarious kinds of sites, and (b) the number density of
Kr atoms located at various kinds of sites.

ous kinds of sites were estimated by multiplying
the implantation dose by the fraction of occupancy; they are shown in Fig. 2(b).
The irradiation effect on the distribution of Kr
atoms was investigated on the 4 X 10 14 Kr/ cm 2
implanted specimen (Fig. 3). After having
obtained the <1 0 0> and <Ill > angular profiles
shown in Fig. l(a), measurements were madeagain around 1/1' = 0°, respectively. These results
indicate that the fraction of R-site occupancy
increased (from 31 to 55% in the case of <1 11>channel) due to the analysis-beam irradiation in
the previous measurement run. Therefore, it isconcluded that the ion irradiation enhances thefraction of R-site occupancy.
As described in previous papers, the T - andO-site occupancies are considered to be a resultof strong interaction between Kr atoms andvacancies introduced during implantation; the Kr
atoms trap multiple vacancies and, accordingly,
are displaced to T- or O-sites to take configuration similar to trivacancy (KrV 4) or pentavacancy (KrV 6) configuration (Fig. 4) .8,9) The R-site
occupancy is considered to represent the Kr
atoms in precipitates.
The dose dependence of the distribution of Kr
atoms shown in Fig. 2 is considered to represent
the evolution of Kr precipitates (Kr bubbles)
under implantation at room temperature. As seenfrom Fig. 2(b), with increasing dose from 4 X 10 14
Kr/cm 2 to 1 X 10 15 /cm 2 , the number density of the
T-site occupancy remained approximately un-

Fig. 3. Effect of ion irradiation on the distribution of
Kr atoms in the 4 x 1014 Kr/ cm 2 implanted specimen.
(a) Just after having obtained the <1 0 0) angularprofile (0, .) shown in Fig. l(a), measurements
were made again for 1/1'::::::=..0. The results are indicated by triangular symbols (6 , .). (b) <11 D angular profiles obtained one year after the measurements of the <111> angular profiles shown in Fig.
l(a), and around specimen area which had been
already analyzed. During one year the specimen had
been kept in air at room temperature. Full curves
and dotted curves were drawn only to guide the eye.

(0)

(b)

Fig. 4. Proposed vacancy-cluster configurations for(a) a trivacancy and (b) a pentavacancy.10) The open
squares and closed circles represent vacancies andinterstitial atoms, respectively. (The interstitialatom in a pentavacancy is displaced slightly froman O-site.) The closed circles may be considered torepresent Kr atoms in the present case.

changed, whereas that of the O-site occupancy
became about 2.5 times larger. This behaviour
suggests that the Kr-vacancy complexes like
KrV 4 (T -site occupancy) trap still morevacancies introduced under implantation andgrow to larger one like KrV 6 (O-site occupancy).
As to the S- and R-site occupancies, the number
density of the S-site occupancy increased only bya factor of l. 5, while that of the R-site occupancy (Kr atoms in precipitates) increased more
rapidly. As described above, irradiation enhances the fraction of the R-site occupancy, i.e.,radiation-enhanced or radiation-induced precipitation. As Kr atoms can move only when they are
assisted by mobile vacancies, the implantationintroduced vacancies enhances diffusion of Kr
atoms.

90

E. Yagi

From these results it is considered that in theearly stage of implantation small Kr-vacancy
complexes such as Kr V 4 and Kr V 6 are formed
and act as trapping centres for Kr atoms andvacancies. When the implantation is continued,
most of the implanted Kr atoms migrate to be
trapped by the Kr-vacancy complexes or alreadyexisting small precipitates, and the precipitation
proceeds; the Kr-vacancy complexes act as nucleation centres for Kr precipitates. Moredetailed descriptions are given in Ref. 11.
References
1) A. vom Felde, ]. Fink, Th. Mliller·Heinzerling, ].
PflUger, B. Scheerer, G. Linker, and D. Kaletta: Phys.
Rev. Lett., 53,922 (1984).
2) C. Templier, C. Jaouen, ].-P. Riviere,]' Delafond, and].Grilhe: C. R. A cad. Sci. Paris, 299, 613 (1984).
3) J. H. Evans and D. J. Mazey:]. Phys. F: Met. Phys.,
15, Ll (1985).
4) R. C. Birtcher and W. Jager: Nucl. Instrum. Methods
Phys. Res. B, 15, 435 (1986).
5) C. Templier, H. Garem, ].-P. Riviere, and J. Delafond:Nucl. Instrum. Methods Phys. Res. B, 13, 24 (1986).
6) S. E. Donnelly and C. J. Rossouw: Nucl. Instrum.
Methods Phys. Res. B, 13, 485 (1986).
7) 1. Hashimoto, H. Yorikawa, H. Mitsuya, H. Yamaguchi, K. Takaishi, T. Kikuchi, K. Furuya, E. Yagi,
and M. Iwaki: ]. Nucl. Mater., 149, 69 (1987).
8) E. Yagi: Phys. Status Solidi A, 104, K13 (1987).
9) E. Yagi, M. Iwaki, K. Tanaka, 1. Hashimoto, and H.
Yamaguchi: Nucl. Instrum. Methods Phys. Res. B, 33 ,
724 (1988).
10) G. H. Vineyard: Discuss. Faraday Soc., No. 31, 7 (1961).
11) E. Yagi: Nucl. Instrum. Methods Phys. Res. B, 39, 68(1989) .

91
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-27. Evaluation of Crystalline Quality and Irradiation Effects
of a Bi-Sr-Ca-Cu-O System High Transition Temperature
Superconductor by Rutherford Backscattering Spectroscopy
T. Kobayashi, S. Takekawa, * M. Iwaki, H. Sakairi, and M. Aono

The Bi-Sr-Ca-Cu-O system is an attractive
superconductor because it is synthesized without
any rare earth and virulence elements and
BiSrCaCu20x samples were found to have thetransition temperature 1'c as high as 105 K. It
endures moreover the environmental water.
Recently a single crystal of the above system,
large enough for physical analyses.' become
available, which is prepared by a floating zone
(FZ) method using infrared heating at the
National Institute for Research in Inorganic
Materials.
In this paper, Rutherford backscattering
spectroscopy (RBS) was applied to this single
crystal to study the structural quality by using
the sensitivity of RBS to lattice imperfections.
The effects of ion bombardment on the structure
were also examined by using RBS probe ion
itself during the RBS measurement.
The approximate dimensions of a specimen
crystal are 5 mm in length, 2 mm in widthand 0.03 mm in thickness. Electron probe X-ray
analysis determined the composition as
Bi2.2Sr1.8Cal.OCu2.o0x. X-ray diffraction analysis

revealed that the largest face of the specimen isparallel to the c-plane. An electric resistancemeasurement gave the Tc value of 91 K. RBS
experiments were carried out with a 4He+ beam
accelerated to 1. 5 MeV with a CockcroftWalton-type tandem accelerator (Tandetron)and collimated to 0.065 in divergence. The
diameter of the beam spot on the specimen surface was 1.0 mm, when the current intensity was
0.7 nA and the flux density was 5.6 X 1011 Hel
cm 2·s. The energy of backscattered 4He particles was analyzed with a surface barrier solidstate detector placed at a scattering angle of 150
at a detecting solid angle of 0.03 sr and with theenergy resolution of the detector of 20 keY. The
specimen temperature was ambient during RBS
experiments.
The RBS spectrum of a Bi2.2Sr1.8Cal.OCu2.o0x
crystal, as shown in Fig. 1, was obtained with
1. 5MeV 4He+ ions incident parallel to the c-axis
after 3.30 X 10 15 Hel cm 2 irradiation. Respectiveenergy positions of 4He ions backscattered by
00

1. 5 - r - - - - - - - - ,c - axlso

ENERGY (MeV)
0.5
1.0
1.5
NO 5.0 , - - - - - ' - - - - - - ' - - - - - - - ' - - ,

-.J
W

I

..... 1. 0
>-

·:.

o

..J
W

~ 2.5
a:

W
N

Ca Cu.ST' Bt

I

I II I•-.J-

a: 0.5::E:'.
•

A............

.

..

0:::

....

o

:::c
u

. . :. ---1:... ...
..-

~~

o

x

.....

0

. . . . . . MO

z:

-b

.~

"en

l-

~ O. O+----,----,----y--~___i
o

u

100

275

450

625

CHRNNEL NUMBER

800

Fig. 1. RBS spectrum of a single crystal of the Bi-SrCa-Cu-O system high Tc superconductor measured
with a 1.5 MeV 4He+ beam in the c-axis after 3.30X
10 15 He/ cm 2 irradiation.

* National Institute for Research in Inorganic Materials

-2

-1

0

1

2

TILT (DEGREES)

Fig. 2. Angular dependence of the intensity of 4Heparticles scattered from bismuth atoms in single crystalof the Bi-Sr-Ca-Cu-O system high Tc superconductor.
The dependence was measured by changing the direction of an incident 4He+ beam around the c- axis. Solidcircles, solid squares, solid triangles, open circles andopen squares represent first, second, third, fourth, andfifth channeling angular scan, respectively.

92

T. Kobayashi, et at.

Bi, Sr, Cu, Ca, and 0 atoms on the specimen
surface were indicated with lines on the spectrum. A clear rise of the spectrum at the surface
was observed only by Bi, which has a larger
Rutherford scattering cross section (18.33 barn/sr) than those of Sr (3.81) , Cu (2.21) , Ca 0.04) ,and 0 (0 . 15) .
In Fig. 2 was shown the channeling dip inbackscattered 4He yields, that is, the variationin the yield with the change in the beam incident
angle around the c-axis direction. In this experiment only 4He ions in a "WINDOW" (shown in
Fig .1) were measured. "WINDOW" was limited
within a spectrum region where only Bi atoms
contribute so that the participation of scatteringby other elements was excluded. The counts ofeach point were accumulated for the exposure of
2.4xI013 He/ cm z •The axial half angle 1/1'1/2 of the dip is calculated out to be 0.69 but the estimation of theminimum yield Xmin is difficult because of its
increase with the fluence of 4He. It is also notedthat the specimen was exposed to a dose of
1.26 x 10 15 He/ cm 2 during alignment of the crystal axis before the first dip measurements. So
the initial value of Xmin was roughly estimated at0,

1. 0,-_ _ _ _ _ _ _ _-,

o
...J
W

r~o.s
:::)
~

z
O. 0+---r--r----,.-~__,r__-1

0.0

2.0

4.0

6.0

(X1015 He/cm 2 )IRRADIATION DOSE
Fig. 3. Plot of Minimum yield Xmin vs. irradiation dose
for the Bi-Sr-Ca-Cu-O system high Tc superconductor.
The solid line is to guide the reader's eye. The Xmin in
the initial stage of bombardment estimated at 0.10.

0.10 by extrapolation of an experimental relation of Xmin and the fluence as shown in Fig. 3.
The results indicate that the BizSrzCaCuzO x crystal has a rather high structural quality in theinitial stage of bombardment. As the fluence of a
He ion beam used for RBS increases, the Xmin
increases . We thus conclude that a structure
disorder is produced by ion bombardment in the
Bi-Sr-Ca-Cu-O system high Tc superconductor bymeans of the FZ method using infrared heating.

93

RIKEN Accel. Prog. Rep. 22 (1988)

111-2-28.

RBS Investigation of N-Implanted AIN x Film Deposited on Silicon
K. Kobayashi, S. Namba, T. Fujihana, T. Kobayashi, and M. Iwaki

Recently aluminium nitride (AIN) is ofpaticular interest because of its large energy gap,
good thermal conductivity, and stability up tovery high temperature, as well as its chemical
inertness. I) We investigated by Rutherford backsca ttering (RBS) measurments the effects of
N -ion implantation on AIN x films deposited byan activated reactive evaporation (ARE) method.
In a previous report,2) we found that the ratio of
Al/N in AIN x film was dependent on the deposition rate during evaporation by ARE. Twoeffects of the N -implantation in AIN x film werealso reported: 3) (i) N -implantation in AIN x (x < 1)films causes the formation of (002) oriented
AIN x films at room temperature without any
thermal annealing, and (ii) the optical transmittance of the AIN x (x < 1) films is improved.
This report, presents the effect of the incident
implantation angle of nitrogen on the composition of the AIN x films deposited on silicon. Since
the detailed conditions of the deposition of AIN x
film by the ARE method was previously
reported,3) key conditions are briefly mentioned
here. AIN x films of 750 nm in thickness were
deposited on Si (111) by means of ARE in a
He·
3000 (a)s~Vergin:;-2000

0.2

0.4

0.6

0.8

1.0

ENERGY(MeV)

Fig. 1. Rutherford backscattering (RBS) spectra for
the AINx-film-deposited Si (111) before and afterN -implantation at an incident angle of 0°. (a), random
and <11 D aligned spectra before N -implantation;(b), random and <11 D aligned spectra after Nimplantation.

nitrogen atmoshere. The base pressure was 2 X
10- 6 Torr and the partial pressure of the nitrogen
during deposition was 1 X 10- 4 Torr by feedingN2 gas into a chamber. The substrate was watercooled and no bias voltage was applied between
the substrate and the evaporation source.
Nitrogen-implantation into the AIN x thin films
was performed to the doses ranging from 5 X 10 16
to 5 X 10 17 N +-ions/ cm 2 at 80 ke V at 1 X 10- 6 Torr.
For 80-keV implantation, the average projected
range calculated by a Lindhard, Scharff andSchiott (LSS) theory was estimated at 180 nm,
which was deeper than the interface. Therefore
the nitrogen implantation was carried out
through the AIN x thin films. The beam density
was approximately 2 J1.A / cm 2 , and the temperature of substrates during ion implantation wasmaintained to be ambient. The incident angle of
N+-ions was changed from 00 to 45
Figure 1 shows RBS random and <Ill >aligned spectra before and after the N implantation to a dose of 5 X 10 17 N+ / cm 2; theincident angle was 0 The marking short lines
indicate the edges of AI, N, and 0 at the surface
and the edge of Si at the interface.
By comparison of Fig. 1 (a) and Fig. 1 (b), theposition of the maximum yield of implanted
nitrogen is deeper than the interface between the
AIN x film and the Si substrate, as predicted fromthe LSS theory. The distribution of the implanted
ni trogen calculated from the difference in the
spectra between pre- and post-implantation is ofa Gaussian-like shape in the Si substrate. The
comparison between aligned and rundom spectrain Fig. 1 (b) indicates that the Si substrate near
the interface would be amorphi zed by Nimplantation. Figure 1 (b) indicates that O-atoms
invaded the surface layers of the film afterN -implantation, since there was no yield corresponding to the 0 atoms in the spectra for apristine film. The 0 atoms invation would occur
by the following process: the O-atoms in the.surface oxide formed by the absorption of contaminations and a cosequent segregation inducedby the cascade mixing accompanied with Nimplantation.
Figure 2 shows RBS spectra for the AIN x film
0

•

0

•

94

K. Kobayashi, et al.

Clo~============~

..J

~3000

Si(l1l)IAIN kN+

He+1.5MeV(b)

N95X1CPN+/cm2
I

>-

2 000

80keV

45'

Random
"

1 000

SiAl

",/ ..,.,_."._... ,~ I

<lll>aligned

0.2

0.4

0.6

ENERGY

0.8

1.0

(MeV)

Fig. 2. Rutherford backscattering (RBS) spectra for
the AIN x film deposited Si (111) after N -ion implantation. (a), random and <1 1 D aligned spectra
after N -implantation at an incident angle of 0 (b),random and <1 1 D aligned spectra after Nimplantation at an incident angle of 45
0

;

0

•

deposited Si (111) after N-ion implantation at
two different incident angles. Figure 2 (a) and (b)show random and <11 D aligned spectra afterN -implantation at incident angles of 0° and 45°,
respectively.
By comparison of Fig. 2 (a) and Fig. 2 (b), theyield of the N atoms implanted at 45° is found tobe smaller than those at 0° at the same doses. The
reduction of the yield would result from thefollowing two reasons: one is the removing ofextra nitrogen due to nitrogen imping and/ or theother is the scattering (reflection) of incident
nitrogen at the surface. These two effects of theremoving and scattering of incident atoms by

implantation would be dependent on the incident
angles.
In comparison with two <111> aligned spectra
shown in Fig. 2 (a) and (b) in Fig. 2, the shaded
peak, which corresponds to the damage of thesilicon substrate, was shifted toward the surface
with increasing the incident angle from 0° to 45°.
This indicates that the amorphous layer near theinterface induced by N -implantation at 45° wasshallower than those at 0°.
During the investigation of the effects of theincident angles of N -implantation near room
temperature on the AIN grain growth by meansof X-ray diffraction (XRD), we also obtained thefollowing results. 4 )(1) The grain growth of AIN took place, evenwhen the incident angles of nitrogen ions weretilted from 0° to 45°.
(2) The c-axis of the grown AIN grains was
normal to the substrate plane, when the incident
angles of nitrogen ions were tilted from 0° to 45°.
Futher investigations will be needed forcontroling the composition and structure of AIN x
by N -implantation.
References
1) A. Fathimulla and A. Lakhani: ]. A ppl. Phys., 54,
4586 (1983) .

2) K. Kobayashi , S. N amba, T. Fujihana, Y. Dai, T.
Kobayashi, and M. Iwaki: RIKEN Accel. Prog. Rep. ,21, 105 (1987 ) .

3) K. Kobayashi , S. Namba, T. Fujihana, T . Kobayashi,
Y. Dai, and M. Iwaki: Appl. Phys. L ett., 53 (3), 18(1988) .

4) K. Kobayashi, S. Namba, T. Fujihana, Y. Dai, T.
Kobayashi, and M. Iwaki: Nucl. Instrum. Methods
Phys. Res. B, 37/ 38, 704 (1989) .

95

RIKEN Accel. Prog. Rep. 22 (1988)

111-2-29.

RBS Investigation of N-Implanted Iron
T. Fujihana, Y. Ok abe, and M. Iwaki

Over the last decate, N ·ion implantation into
Fe and steels has been employed in fundamental
studies on surface layer modification. In particular, the N-concentration profile as a function of
depth is one of the most important subjects forthe research on implanted layers, and has been
investigated by means of secondary ion mass
spectroscopy (SIMS),l) Auger electron spectroscopy (AES),2) and so on. However, these analyses
are accompanied with ion beam sputtering whichholds possiblility that selective sputtering, cascade mixing, etc. would take place, and the
sputtering ratio may differ between matrix andimplanted layers due to new compound formation by ion implantation. It is important to compare the results of these analyses with those of
Rutherford backscattering (RBS) measurement
which have no such effects of sputtering.
The present report describes the preliminary
results of RBS measurements on the surface
compositions of N -implanted Fe-surface layers.
The ion implantation of 14N+ into Fe plates of
1 mm in thickness with a purity of 99.9% was
performed with doses ranging from 1 X 10 17 to 1 x
10 18 ions/ cm 2 at 100 keV at 20°C. The ion beam
current density was approximately 1.0 fJ.A / cm 2.
In order to investigate temperature dependence,
substrate temperature during implantation witha dose of 5X 10 17 ions/ cm 2 was kept at -40, 20,100, or 200°C by cooling substrate holders withliquid nitrogen or water, or warming them up
with a heater. These temperatures were monitored with a pair of alumel-chromel thermocouple
fixed on the substrate holders. The pressure in aprocess chamber during implantation wasapproximately 1.5 X 10- 4Pa.
The RBS measurement was carried out by
using 1.5 MeV 4He+ ions with a fluence of 3 fJ.C
to estimate the compositions of N -implanted
Fe-surface layers. Backscattered particles weredetected at an angle of 150 degrees and analyzed
with a solid state detector and conventional
electronics. The specimens were mounted on agoniometer in a target chamber, where the pressure was below 5 X 10- 4Pa.
Figure 1 shows the RBS spectra for the specimens unimplanted and N-implanted with a dose

Fig. 1. RBS spectra for unimplanted and Nimplanted Fe with a dose of 5 x 10 17 ions/ cm 2 at 20°C.

of 5 X 10 17 ions/ cm 2 at 20°C. The leading edge of
the Fe surface is at the channel number 574(located at half-height) and the energy edge of
implanted N atoms at the Fe-surface at channel
number 250. Comparison of the spectra obtainedwith the unimplanted specimen and with the
N -implanted specimen indicates that the increasein the RBS yield induced by implanted N -atoms
can hardly be observed, but the N -depth profile
can be expected from the decrease in the 'yield of
the Fe-atoms owing to implanted N atoms.
Figure 2 shows the relationship between tentative N concentrations and backscattering energy
as a function of N dose for 20°C implantation.
The tentative N concentrations are defined by
the ratio of decreasing yields in the N -implanted
Fe-surface layers (l-Fej/Fe u), which are calculated from RBS spectra, e.g., as shown in Fig. 1.
Here Fej and Feu are the yields for Fe-atoms of
the implanted and of the unimplanted specimens,
respectively, at the same backscattering energy.
The N doses for (a), (b), (c), and (d) in Fig. 2 are
lxI017, 2.5xI017, 5xI017, and lxI0 18 ions/ cm 2 ,respectively. The profiles of tentative N concentrations below the dose of 2.5 x 10 17 ions/ cm 2 aresimilar to those of the implanted N a toms
predicted by the LSS theory,3) indicating theGaussian distribution. When implanted at thedose of 5 x 10 17 ions/cm 2 , the specimen shows its
maximum N concentration slightly lower than
the theoretical value, though the profile shows a

96

T. Fujihana, et al.

Fig. 2. Profiles of the tentative N concentrations for
implanted Fe at 20°C with various doses. (a), 1 x 10 17 ;(b), 2.5 x 1017; (c), 5 x 1017; (d) 1 x 10 18 ions/ cm 2 • Fe,
and Feu are the yields for Fe-atoms of the implanted
and unimplanted specimens, respectively.

Fig. 3. Profiles of the tentative N concentrations for
implanted at a dose of 5 x 10 17 ions/ cm 2 with various
substrate temperatures during implantation. Fe, andFeu are the yields for the implanted and unimplanted specimens, respectively.

Gaussian distribution. Comparison of (c) and (d)indicates that the maximum N concentration at
1 X 10 18 ions/cm 2 does not exceed the one at 5 X
10 17 ions/cm 2, and implanted N atoms migrate
towards the Fe surface. The saturation of Nconcentration in Fe during implantation, themaximum of which is approximately 30 at%,was previously obtained by our AES measurements. 2) The saturation phenomena like this arealso reported for the N implantation into Al,4)TV) and Cr,2) and in each case the n1aximum N
concentration is approximately 50 at%. If no
migration of N atoms occur and the N distribution is caused due to sputtering during implantation, the maximum N concentration in Fe would
be almost identical to the one in Cr because themass, atomic number, and density of Fe arenearly the same as those of Cr. These results
indicate that the migration of N atoms causes thechange of N distribution from a Gaussian type toan error-functional type in accordance with theincrease in N dose.
Figure 3 shows the profiles of the tentative N
concentration for N -implanted specimens at adose of 5 X 10 17 ions/ cm 2 as a function of substratetemperature during implantation. The substratetemperatures during implantation are indicatedin the figure. The Gaussian-distribution is observed for the implantation below 100°C. The
profile for 200°C implantation is quite different
from others and shows an error-functional distribution. The result suggests that the migrationof N atoms is enhanced in the implantation at
200°C, as shown for the specimen with a dose of
1 x 10 18 ions/ cm z in Fig. 2.
From these results, we conclude that in thehigh-dose N -implantation into Fe, the migrationof N -atoms occurs towards the Fe-surface evenduring 20°C implantation and is enhanced at
higher temperatures, and consequently, the depth
profile of the implanted N atoms has an errorfunctional distribution.
References
1) M. Iwaki, T. Fujihana, and K. Okitaka: Mater. Sci.

Eng., 69, 211 (1985).
2) T. Fujihana, Y. Okabe, and M. Iwaki: Proc. Int. Cont.
Surface Modification of Metals by Ion Beams, Riva
Del Garda, Italy, 1988, to be published.
3) ]. Lindhard, M. Scharff, and H. E. Schi<l>tt: K. Dan.
Vidensk. Selsk. Mat. -Fys. Medd., 33 (14), 1 (1963).
4) S. Ohira and M. Iwaki: Mater. Sci. Eng., 90, 143(1987).

97

RIKEN Accel. Prog. Rep. 22 (1988)

111-2-30.

Hydrogen Trapping by Solute Atoms in Nb-Mo Alloys
as Observed by a Channelling Method
E. Vagi, T. Kobayashi, and T. Matsumoto*

The enhancement of the terminal solubility forhydrogen (TSH) in group Va metals (V, Nb, andTa) on alloying with metal solute atoms has beenreported for various alloying elements. i,2) For themechanism of this enhancement a trapping
model has been proposed.1- 3 ) On the other hand,
it has also been reported that no evidence fortrapping was observed,4) and it has been suggested that the enhancement is explained only on thebasis of the concept of macroscopic
thermodynamics. 5 ) To elucidate the mechanismof this enhancement, the lattice location ofhydrogen has been investigated by a channelling
method using a nuclear reaction IHeiB, a ) aa,6-8)
on the Nb alloys containing undersized Mo
atoms. 9)
In a prev ious study on Nb-3at%Mo alloys thefollowing conclusion was deduced. 9) In a Nb3at%Mo-2at%H alloy all hydrogen atoms aretrapped by Mo atoms at room temperature andlocated at sites displaced from tetrahedral (T)sites by about O. 6ft.. towards the Mo atoms(trapped sites). In a Nb-3at%-5at%H alloy somefraction of hydrogen atoms are located at thetrapped sites and the rest are at T -sites at room
temperature, while at 373 K they are detrappedand enter T-sites. These results give direct evidence for the existence of attractive interaction
between substitutional solute atoms and hydrogen in Nb-3at%Mo alloys and strongly support
the trapping model for the enhancement of theTSH in Nb by alloying with Mo atoms in the low
concentration region of Mo solute atoms.
In the present study, experiments wereextended to the alloy containing higher concentration of Mo atoms ('"'-' 10at%). The experiments
were performed at room temperature with a 2.03
MeV 11B2+ beam on a Nb-10at%Mo -6at%H alloy,
and channelling angular profiles of backscattered lIB and emitted a particles were obtained for<1 0 0) , <1 1 0) and {I 0 O} channels. The results
are shown in Fig. 1.
These a -angular profiles are very similar to
those for the Nb-3at%-5at%H alloy. For exam* National Research Institute for Metals.

1.5

(100)

(11 0){10 0)

·H
• Nb

,t',

g
0

W
N

::i

«

2:

a:

~ 0.5

v

~

Nb- 10%Mo-6"1oH
0 ~~-~
2 ~0~~~~-~2~~0~~~---~1~0~~~

ANGLE (d eg l

Fig. 1. Channelling angular profiles of a particle
and back scattered II B yields obtained at room temperature for Nb-10at%Mo-6at%H alloy. The fullcurves and the dashed curves were drawn to guidethe eye.

pIe, for the ( 110) channel small subpeaks wereobserved at 0°, - 0.35°, and - 0.6° in both alloys.
These results indicate that some fraction ofhydrogen atoms are located at trapped sites andthe rest are at T-sites, because the subpeaks at 0°
and - 0 . 35° are attributed to the T -si teoccupancy,lO) and at - 0 . 6° to the trapped site
occupancy.9) The trapping efficiency, f, the number of H atoms trapped by one Mo atom, wasroughly estimated at 0.67-1. 0 for the Nb-3at%
Mo-5at%H alloy,9' and at 0.25-0 .35 for the
Nb-10at%Mo-6at%H alloy. The decrease in thetrapping efficiency with increasing Mo concentration is considered to be a result that the effectof strain due to undersized Mo atoms does not
become strongly localized with increasing Mo
concentration. Experiments on more concentrated alloys are in progress.
References
1) J. F. Miller and D. G. Westlake: Proc. 2nd JIM Int.
Symp. Hydrogen in Metals, Supple Trans. Jpn. Inst.
Metals, 21, 153 (1980).
2) T. Matsumoto, Y. Sasaki, and M. Hihara: ]. Phys.
Chem. Solids , 36, 215 (1975).
3) T. Matsumoto: ]. Phys. Soc. Jpn., 42, 1583 (1977) .
4) D. T. Peterson and S. O. Nelson: Metall. Trans., 16A,
367 (1985).

98

E. Yagi, et al.

5) W. A. Oates and T. B. Flanagan: Acta Metall., 33, 693(1985) .
6) E. Yagi, T. Kobayashi, S. Nakamura, Y. Fukai, andK. Watanabe: l. Phys. Soc. lpn., 52, 3441 (1983).
7) E. Yagi, T. Kobayashi, S. Nakamura, Y. Fukai, andK. Watanabe: Phys. Rev. B, 31,1640 (1985).
8) E. Yagi, T. Kobayashi, S. Nakamura, F. Kano, K.

Watanabe, Y. Fukai, and S. Koike: Phys. Rev. B, 33,
5121 (1986).
9) E. Yagi, S. Nakamura, F. Kano, T. Kobayashi, K.
Watanabe, Y. Fukai, and T. Matsumoto: Phys. Rev.
B, 39, 57 (1989) .
10) E. Yagi, S. Nakamura, T. Kobayashi, K. Watanabe,
and Y. Fukai: ]. Phys. Soc. lPn., 54, 1855 (1985).

99
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-31.

Radiation Damage in lon-Implanted CaF2 Observed by Channeling
K. Aono, M. I waki, and S. N amba

In our previous reports,l,2) we have presented
the results on the radiation dama'g e and depth
profiles of Eu in Eu-implanted CaF 2 investigatedby an RES-channeling method using the TANDETRON. These results indicate that the 100
keY Eu-implantation does not produce severeradiation damage. In the ion implantation into
CaF 2 studied with various ions (Cr+, Fe+, Cu+ ,and Eu+), we found that the color of luminescence emitted from CaF 2 during ion-implantation
varies as a function of the implantation-dose. In
addition, the originally colorless and transparent
properties of CaF 2 wafers did not change evenafter a considerable ion implantation to a dose of
10 16 ions/ cm 2; these phenomena may be causedby the alternations in ion-states depending on thedose.
In the present study, the radiation damage of
Cr-implanted CaF 2 was investigated by the same
method as that used in the Eu implantation.
Chromium, iron, copper, and europium ions of
100 keY were implanted into colorless and transparent single crystalline CaF 2 wafers with dosesof lOl L 10 16 / cm 2. The channeling measurement
was carried out by using l.5 MeV He+, andbackscattered particles were detected at anangle of 150°. With Eu, the heaviest of these ions,the color of luminescence emitted from CaF 2
during Eu-implantation changed sensitively withdose. It is known that in the early stage of ion
implantation, both ionic states of Eu 2+ and Eu3+
are dominant and at the high dose implantation
Eu3+ is dominant. 2) The <1 1 1) channeling measurements show that there is a little difference inthe minimum yield of the backscattering between
fluences of 10 13 and 10 16 / cm 2. These results canbe explained in terms of the stability of the ionicstates in the CaF 2 matrix. As the stress in theimplanted layers becomes high with increasing
dose, the Eu 3 + state will be more stable than the

Ul

+'

g3000

()

ENERGY (Mev)

Fig.!. Random (.) and <1 1 1> aligned ( 0 ) spectra
obtained for Cr· implanted CaF z with 1 X 10 16 Cr/ cm 2 ,and <1 1 1> aligned spectra for CaF 2 implanted with
1X10 15 Cr/ cm 2 ( . ), 1 x 10 14 Cr/ cm 2 (L:-.), and 1X10 13
Cr/ cm z ( x ) .

Eu 2 + state, the ionic radius of which (l.12 A) islarger than that of the former (0.98 A). However, in the case of Cr that is the lightest ion in
the above-mentioned ions, the change in color of
the luminescence as a function of theimplantation-dose was not so significant as was
the case of Eu, and the channeling measurementshows a difference in the minimum yield between
fluences of 10 13 and 10 16 / cm 2 , as shown in Fig.I.
Since the ionic radius of Cr ion is smaller thanthat of Ca 2+(0.99 A), the stress of compression in
the Cr-implanted layers may increase slowly
with increasing Cr-dose. Further investigations
are needed for more accurate explanation ofthese phenomena.
References
1) K. Aono, M. Iwaki, and S. Namba: RIKEN Acce!.
Prog. Rep. , 20, 79 (1986).
2) K. Aono, M. Iwaki, and S. Namba: Nucl. Instrum.
Methods Phys. Res. B, 32, 321 (1988).

100
RIKEN Accel. Prog. Rep. 22 (1 988)

111-2-32.

PIXE-Channeling Analysis of Ga in the Ge Epitaxial Layeron a Si Substrate
K. Tanaka and E. Vagi

RBS-channeling is an effective tool for investigating lattice location of impurity atoms; however, detection of a light element in a heavy
matrix is difficult by RBS. Thus, the applicationof RES-channeling has been limited to the analysis of a heavy element in a light matrix. On theother hand, PIXE can be applied to the analysis
of elements in any combinations of hosts and
A

GeK",

t

o

5.0

G:Ks

10.0

15.0

X-ray Energy (keV)

impuri ties, and the impact parameter of K -shell
excitation which is in the order of 10- 2 A issmaller than the Thomas-Fermi screening
radius.1),2) In the present study, therefore, we used
the PIXE-channeling method together with an
RBS-channeling method to investigate the lattice
location of Ga atoms doped in the Ge epitax ial
layer on a Si(l 00) substrate.
Ge layers were grown on a Si(l 0 0) substrateby using a molecular beam epitaxy method andby a two-step procedure in order to reduce thelattice mismatch between Ge and Si. 3 ) In thiswork the growth temperature of the first layer
was kept at 300°C and that of the second layer at
550°C. The thickness of the first la yer was
2,000 A and that of the second layer was 7,000 A.
Ga was evaporated simultaneously with the second Ge layer growth so that the Ga atoms were
distributed homogeneously in the depth of-Random
3000"01. 0Ge~ 0. 8"0.~ 0.6. . . .....'..:.:... I

III

c2000
:J

8

'<h:""",

Si

I

1000

.:..,, x4••-p•••••••• ••••: ...... ................. .......... . .

.., . :

'I>~•••• ~ ••••

~ 0.4
0

Z

0L--8~0-0--~10~O~0~~~12~OO~--~14~O~0~~'6~OO
Scattered H Energy(keV) .

Fig. 1. Energy spectra of X rays and backscatteredprotons for a Ga-doped Ge layer on a Si substrate.
(A) PIXE spectrum with polyester film of 1 mm inthickness; (B) RBS spectrum.

r

<100>

4<100> aligned

8

0. 2

_a_o~

°e

.\

....
i:I
,/...•••l"'~~o',,(,.

s~\

<111>

.j

t

°1 1I,~o>.~o"' jl\1• II.r°i\" Ii0
o·.. Io~:r\0"",0

~

1

2

"=s>'
-2 - 1 0 1
Angle(deg )

I

,II

\ L

\ff,/6<r;;l0-2 - 1 0

<110>

2

-2

-1

0

1

Fig. 2. Channeling angular profil es of protons ( 0 ) , Ge
X-rays ( . ) and Ga X-ra ys ( 6 ) yields for a Ga·
doped Ge layer on a Si substrate.

Table 1. Values of <PI /2- and Xm lo· for backscattered protons, Ge Ka X-rays and Ga Ka X-ra ys through the<1 00>, <1 10>, and <1 1l> axes.
Ga X-rayGe X-ray

B.s.

B.s.

(Ka)

(Ka)

(Whole Ge layer)(N ear surface)

B.S.
(Ge/ Si interface)

<P1/2

0.75

0.43

0.45

0.50

0.38

Xmlo

0.42

0.10

0.10

0.06

0.16

<P 1/ 2

0.43

0.45

0.45

0.50

0.45

XmlO

0.61

0.13

0.12

0.05

0.18

<P 1/2

0.45

0.38

0.43

0.45

0.39

Xmlo

0.50

0.22

0.18

0.07

0.31

<1 00 >

<1 10><11D

K. Tanaka, et al.

4,000 A below the surface. The concentration of
a Ga was 1 X 10 18 atoms/cm 3 • Channeling analysis
was carried out with a 1.5 MeV proton beam.
The beam diameter was 1 mm and the beam
divergence was less than O.OT; the current wasapproximately 10 nA. The characteristic X-rays
emitted from the sample were detected with aSi(Li) detector which has a sensitive area of 30
mm 2 and a 3 mm depletion depth, viewed thesample at 135° to the beam direction. The distance between the sample surface and the detector was 90 mm. An X-ray detector has a Be
window of 7.5 J1 m in thickness. We used an
additional polyester film of 1 mm in thickness to
reduce Si X-rays from the substrate of the sample and avoid pulse pile-up effects. Scattering
protons were detected with a surface barrier
solid-state detector at a scattering angle of 155°.
Figure 1 shows typical spectra of PIXE and of
the backscattered protons for <1 00) aligned andrandom incidences. A notable peak observed in
the spectra for the <100) aligned case arises
from the dislocations at the Ge/ Si interface. In
order to investigate the lattice location of Ga
atoms, we performed channeling angular scansthrough <1 0 0) , <11 0) , and <Ill ) axes. Figure 2
shows the angular scans for the backscatteredprotons, Ge Ka X-rays, and Ga Ka X-rays. The
backscattering proton signals accepted for the101

angular scans correspond to a thickness of
1,200 A below the surface. The half-width of achanneling dip at a level halfway between theminimum and random level (cjJ 112) and the normalized minimum yield (Xmln) for each angularscans are summarized in Table 1. Also performed were angular scans for the backscattering proton signals corresponding to a thicknessof 1,200 A near the Ge/ Si interface and the whole
Ge layer. Their cjJ 112-values and Xmln-values are
summarized in Table 1. The angular scan curvefor Ge Ka X-ray agrees with that for the whole
Ge layer. The <100) , <110) , and <Ill) Ga Ka
X-rays angular profiles exhibit clear dips. We
concluded that 50% of Ga atoms are located at
substitutional sites and 50% at random sites. We
confirmed that the PIXE method can be applied
to ion-channeling analysis of the Ga lattice location in a Ge layer.
References
J. Mayer, and S. Picraux: Materials
Analysis by Ion Channeling, Academic Press, NewYork (1982).
2) J. Chemin, I. Mitchell, and F. Saris: J Appl. Phys. , 45,532 (1974).
3) Y. Fukuda and Y. Kohama: J Cryst. Growth, 81, 451(1987) .
1) L. Feldman,

102
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-33.

Chemical Erosion of Molybdenum Disulphide (MoS 2 )by Hydrogen Plasma
K. Yano, Y. Sakamoto, H. Oyama, M. Yanokura,
H. Kokai, S. Hoh, * and A. Miyahara **Molybdenum disulphide is widely utilized, as asuitable lubricant in an ultrahigh vacuum. We
need application of MoS z in fusion devices; inreality, screw systems with MoS z lubricant are
utilized to drive the graphite blades in an AL T-II
pumped limiter in a TEXTOR device. Underhydrogen plasma irradiation, however, this lubricant would be deteriorated by erosion of sulphur
through a chemical reaction: MoSz+4H~2HzS+
Mo. Dimigen and others have reported that thecontent of sulphur in MoS x is an essential factor
for the tribological properties of this lubricant. I)
Thus it is necessary to have data on the chemical
erosion of MoS z by irradiation of H + and/ or H O
flux from a hydrogen plasma as a part oftribological studies of MoS z.
The present erosion experiment has been carried out using hydrogen plasma produced bymeans of an electron cyclotron resonance (ECR)
discharge. The ECR-2 device used in this experiment has been described in Ref.2. Throughout
experiments, plasma conditions were as follows:
Hz gas pressure, 4 X 10-z Pa; microwave frequency, 2.45 GHz; power, 200 W in CW; electron
density, ne = 2.7 X 10 10 cm- 3 ; and electron temperature, Te = 10 eV.
Thin (l,um) MoS z were deposited on SUS 304
stainless steel substrates by sputtering. The samples were irradiated at two positions for (1)hybrid irradiation Cions+neutrals) and (2) irradiation of the Franck-Condon neutrals only. The
sample temperature was monitored with a thermocouple. Chemical erosion of MoS z was investigated mainly by Auger Electron Spectroscopy(AES) .The stoichiometry of the MoS z film
examined by AES was found to be Mo : S = 1:
2. Before plasma irradiation, a sample washeated up to 350°C in vacuum and no change inthe stoichiometry was verified by AES.
The hybrid irradiation was carried out by
varying the bias voltage from 0 to - 300 volts
with respect to the potential of the grounded* Toshiba Corporation.
** IPP Nagoya, Nagoya University.

x 100
1.0 . - - - - - - - - -- - - ,(0) os received
Sulphur(b) earth potential

i: 0.8c.2(c) Vbias~ 0.6=100 V

(0)

(];

~ 0.4

8
.~

0.2

o

«

0 L----'-------'------'---'---'_-'----'------l
2345678

Sputter time (min)Fig. 1. Depth profiles of sulphur after hybrid irradiation with hydrogen ions of 30 e V (earth potential)
and 100 eV, along with "as received." The sputter
rate is ca. 10 nm/ min.

xl00

1.0 , - - - - - - - - - - - - - - - . ,

~ 0.8
c

o

~ 0.6
C

Sulphur(0) neutral(b) Vbias = 200 V(c) Vbias = 300 V
(0)

~ 0.4

8

Sputter time (min)Fig. 2. Depth profiles of sulphur after hybrid irradiation with hydrogen ions of 200 eV and 300eV, alongwith neutral atom irradiation. The sputter rate isca. 100 nm/ min.

chamber. The zero bias voltage gives the sample -30 V with respect to the plasma due to thepositive space potential of the plasma. Figure 1
shows the depth profiles of sulphur for "asreceived," zero bias voltage ( - 30 V ), and -100
V, and Fig. 2 for -200 V, -300 V, and neutral
irradiation. The sputter rate is 10 nm/ min and
100 nm/ min in the cases of Fig. 1 and Fig. 2,
respectively. Molybdenum was not depleted byirradiation. A prominent decrease in sulphur
near the surface is noticed even for the zero bias
voltage. Ions of an energy above 200 e V cause avirtually complete loss of sulphur from a MoS z
film. Unfortunately, at -200 V and -300 V,
films were partially cracked and exfoliated due

K. Yano, et al.

to thermal stress. The ion fluence was evaluatedto be 2 X 10 20 cm- 2 in this irradiation from current
measurement.
In the case of the Franck -Condon neutral irradiation' sulphur was eroded near the surface (50nm) only. The neutral atom fluence in this irradiation was estimated at 1 x 10 20 atoms cm- 2 fromplasma parameter measurement. The neutral
atoms have the energy of about 5 eV because
their origin is the Franck-Condon dissociation.
The experiment shows that the sulphur atoms of
MoS 2 are removed by hydrogen ions and atoms.
On the basis of the depth profile on the erosion ofsulphur shown in Fig. 1, the depleted thickness
can be estimated at 50 nm, under the assumptionthat the sulphur atoms in the thickness corresponding to sputter time of 5 minutes are103

removed by ions of 100 eV. The mass density of
MoS 2 (4.8 g cm- 3 ) gives a mean atomic distanceof 0.57 nm. Thus the total number of sulphur
atoms in the thickness of 50 nm per cm 2 is about
1.4 X 10 18 • Therefore, the erosion efficiency byions of 100 eV is about 10- 2 sulphur atoms/hydrogen ion. The measurement of the amount of theretained hydrogen by the ERD was tried, but was
not successful because of the large amount ofhydrogen contained in the MoS 2 specimen itself.
References
1) H.Dimigen, H.Huebsch, and P.Willich: Thin Solid
Films, 129, 79 (1985).
2) K.Yano, H.Oyama,Y.Sakamoto, and M.Yanokura:
RIKEN Accel. Prog. Rep., 21, 114 (1987).

104
RIKEN Accel. Prog. Rep. 22 (1988)

111-2-34.

Charge Collection Measurements for the Studyon Single Event Upset
Y. Shimano

Single event upset in semiconductor memories
has increasingly been concerned when integrated
circuits are scaled down in size. 1) The upset is
known to be caused by a rapid drift current
termed "funneling." Because of the intrest in
predicting the single event upset rate in the spaceenvironment, we performed charge collection
measurements for N ions incident on p+-n junctions in n-Si and on n+ -p junctions in p-Si.
In this experment we used 76.1 MeV 14N-ionsfrom the cyclotron. We exposed four kinds ofsamples to these ions: two p-Si samples with NA(the acceptor concentration) = 1 X 10 15 / cm 2 and5 X 10 15 / cm 2 , two n-Si samples with ND (thedonor concentration) = 1 X 10 15 / cm 2 and 5 X 10 15 /cm 2 • These samples were large-area diodes(1, OOO,um xl, OOO,um), and were reverse biased.
Figure 1 schematically shows our experimental
apparatus. The signal was integrated with awide-bandwidth GaAs amplifier and transmitted
to a pulse-shape digitizer. Figure 2 shows theamplifier circuit. The samples were mounted atincident angles 8 = 0, 30, and 60 to a beam, andthe applied bias was varied Vb = 5, 10, and 16
volts.
Figure 3 presents the experimental results witha peak value of the pulse aquired by the pulseshape digitizer as a function of the effective
depletion-layer length, which was varied according to NA (or ND), 8, and Vb. The peak value inm V is expected to be equivalent to the total
charge collected through the funneling process.
Thus, as shown in Fig. 3. the total charge isreasonably proportional to the effective depletion layer length. However, the total charge isapparently greater than the charge ionized by Nions within the depletion layer. Therefore theeffective funnel length WI, which is termed inplace of the effective depletion-layer length Wd,
would be expressed by
WI = /3 X Wd
(1)
where /3 is the constant, but will change with ajunction type (n+ -p or p+ on) and incident particle,
and its energy or LET. For example, /3=2.65 for76.1 MeV N ion and an n+-p junction.
Aiming to investigate the /3 value for high-P U L S E
S HAP ED J G.

~

Nn ~P-J B~ -Fig. 1.

Experimental apparatus.

Fig. 2.

Amplifier circuit.

40 .00 r - - , - - - - - , - - - . - - - r - , - - - - - - - ,-p--"-". N

030.00 f - - - + -- - \ - --++-->-I------i

.

o

E
Q)

g' 20.00 t----t---G'ft----7'-t---+--1

o

>

..Y:

o

Q)

0.

1-0 00 t---7'!-7"-----t-- - + - -f----J
Od eg 30deg 60deg

IxlO

l5

2
/c m 0()•5xlOl5 /c m2.D.
oooo~-~-~-~--~~.0000 1.000 2000 3.000 4.000 5.000
Depletion Layer (/.I m)

Fig. 3. Depletion layer-peak voltage (14 N (76.1
Me V) irradiation).

LET particles abundant in the cosmic rays, suchas Fe and Ni, we will continue simi lIar experiments on heavier particles.
Reference
1) T. R. Oldman and F. B. McLean: IEEE Trans., NS30, 4493 (1983).

105

RIKEN Accel. Prog. Rep. 22 (1988)

111-2-35.

Correlation of Particle-I nduced Displacement Damage
in Si and GaAs
N. Hayashi, H. Watanabe, 1. Sakamoto, K. Kuriyama,*
H. Kawahara, * and I. Kohno

The total energy imparted in nonionizing collisions by recoil atoms in silicon was calculated asa function of proton energy by various authors. I)
The caluculation has been extended also to cover
the proton-induced displacement damage in gallium arsenide. 2) Summers, et at. 3 ) compared theircaluculations with experimental results on the
proton-bombarded silicon bipolar transistors,
and they found a good correlation in their systematic study of displacement damage factors.
In this study resistivity and Hall mobility
measurements in ion irradiated bulk silicon havebeen made with changing incident proton energy.
We have also measured photoconductivity ingallium arsenide at low temperatures and found,
for the first time to our knowledge, that themeasurement is sensitive to the induced displacement damage. Furthermore, the correlation of
the displacement damages produced by protons
and neutrons respectively has been studied tomake clear how cascade structures affect formation of stable defects.
The energy spectrum and spatial directions ofprimary knock-on atoms (PKAs) depend on thetype and energy of the incident particles.
Because of the different PKA spectra, it is'expected that the final damage would differ
when different incident particles are used andresult in different property changes (damage
factors) such as carrier removal and mobility
degradation. A main point in the irradiation
experiments, therefore, is whether it is possible
to establish a correlation of device degradationfor various incident particles.
Proton irradiation was performed with thecyclotron. The proton energies of 6, 9, and 15
Me V were selected to give mean ranges over the
specimen thickness of 100-350 ,urn. The neutron
irradiation was carried out within a standard
neutron field with an energy of 14 Me V at
Electrotechnical Laboratory. The resistivity andHall mobility were measured in the van der
Pauw geometry of square-shaped Si specimens.
* Hosei University, Koganei.

fhId...------r-----r---...----.

!
.~
:~

&!

2
10

MeV p"ro"9 MeV prolon.i~.-'15 MeV prolon...../

0~4MeVneutron
10 1013

1014

1015

Fluence [ions/cm2 j

Fig. 1. Resistivity vs. proton and neutron fluence forn-type silicon samples.

The photoconductance in semi-insulating GaAs
was measured at a temperature range of 80-300
K from the photoexcitation of a light-emitting
diode with a peak wavelength of 940 nm at an
intensity of 640 m W.4)
Figure 1 shows a typical result of the resistivity change in irradiated n-type Si. The resistance apparently increases with increasing proton
fluence and it also depends on whether the projectiles are neutrons or protons. The resistivity
change results mainly from the carrier removal
due to induced defects and can be analyzed interms of a damage factor, K r . The rate of resistivity change is thus expressed as(R - Ro) / R = Kr X ¢>where Ro is the initial resistivity, and R is thatafter exposure to a fluence of ¢ particles/ cm 2 •It was reported that the displacement damage
by protons of MeV energies is mainly due toelastic scattering by the coulomb field of a
nucleus (Rutherford scattering) and that the damage factor is directly proportional to the total
number of initially produced defects.3) It is, therefore, expected that Kr will decrease monotonically with increasing proton energy. The result in
Fig. 1 is consistent with the consideration andalso with previously reported results. 3)
Figure 2 shows the temperature dependence ofthe photoconductance in proton and neutron
irradiated GaAs; two types of the specimens
were used, i.e., In-doped GaAs with an etch pit
density (EPD) of 10/cm 2 and undoped GaAs withan EPD of 10 5 /cm 2 • It should be noted that the

106

N. Hayashi, et al.

5'16

4

T(K)
500 300 200 150

100
/

80

/

/

16

/unirro.
/ (undopedl

4

/

I"

.....~rolon
••••

"S

unirro.
lIn doped)

g
~165

-c

8

0

<5
.C-

I

a..

I

16

6

,.,)

,/)0"0~II

4

8 10 12r l (103'K- 1)
6

I

I

I

r

Fig. 2. Temperature dependence of photoconduct·
ance in In doped (solid lines) and undoped (brokenline) GaAs before and after irradiatoin. The fluen·
ces were 3XI0 13 cm- 2 for 15 MeV proton and 5 X
10 12 cm- 2 for 14 MeV neutron. No change wasobserved in undoped GaAs after neutron irradia·tion.

Quenching phenomenon observed around 100-150
K is enhanced with proton irradiation. The enhancement is prominent for a nearly dislocationfree In-doped GaAs. Therefore, the results indi-cate that the irradiation-induced defects assist
the transition from a midgap electron trap state(EL2°) to its metastable state (EL2*).
Figures 1 and 2 apparently indicate that thecorrelation of displacement damage for neutron
and proton irradiations is similar in Si and GaAs.
The present results suggest that the irradiation
effects induced by nonionizing elastic collisions
are independent of the PKA spectrum and notaffected by defect cascades. Thus, the damage
factor is expected to be less by a factor of about
5-3 in neutron irradiation than in proton irradiation; the correlation is confirmed by a further
experment of neutron irradiation to GaAs. It isremarkable that we detected the effect of neutron irradiation with such a low fluence as lessthan 10 13 n/ cm 2 •References
1) For example, E.A. Burke: IEEE Trans. Nuc!. Sci.,

NS33, 1276 (1986).
2) E.A. Burke: IEEE Trans. Nuc!. Sci., NS34, 1220
(1987) .
3) G.P. Summers, E.A. Burke, c.]. Dale, E.A. Wolicki,

P.W. Marshal, and M.A. Gehlhausen: IEEE Trans.
Nuc!. Sci., NS34, 1134 (1987).
4) K. Kuriyama, H. Kawahara, M. Satoh, and T. Kawakubo: Appl. Phys. Lett., 53,1074 (1988) .

107
RIKEN Accel. Prog. Rep. 22 (1988)

111·3.

Radiochemistry and Nuclear Chemistry
1. Study on Incorporation of Carbon, Boron, and Oxygen
in LEC-GaAs Using Charged Particle Activation
Y. Itoh, Y. Kadota, H. Fukushima, N. Nonaka,
K. Tachi, and T. N ozaki

Carbon, boron, and oxygen are the most important residual impurities in undoped gallium arsenide (GaAs) single crystals grown by theliquid-encapsulated Czochralski (LEC) method. 1)
These impurities are inevitably introduced, since
the ingot is grown from a GaAs melt covered
with a B2 0 3 encapsulant in a pyrolytic boron
nitride crucible sustained in a graphite heater.
The behavior of these impurities during crystal
growth and their effects on the electrical properties of a semi-insulating LEC GaAs matrix
remain obscure, primarily because of the deficiency of the reliable methods for the analysis at
ppb levels. We have reported the determinationof carbon and boron in LEC-GaAs by means of
deuteron activation analysis with the simultaneous 12C(d, n)13N and natB(d, xn)IIC reactions. 2,3)
We used this method to obtain the calibration
factor in IR spectrometry of carbon in GaAs.4)
For boron analysis, secondary ion mass spectroscopy has been used. Commercial LEC-GaAs sam-pIes were reported to contain 10 16 to 10 18 B
atoms • cm- 3 and 10 15 C atoms· cm- 3 , respectively.5) As for oxygen in GaAs, little has everbeen studied though its determination by the
160 eRe, p) 18F reaction has been reported. 6,7) As
samples for the study on the behavior of C, B,
and 0 in the crystal growth, four ingots weregrown under different atmospheric conditions
especially on the introduction of C and 0 fromthe ambient atmosphere into the crystal. Carbon
is found to be introduced to the crystal as COformed from the graphite heater.
Table 1 shows the concentrations of C, B, ando in eight samples cut from the top and bottom
positions of four ingots grown in three different
ambiences (Ar, Ar + 1% O2 , and Ar+ 1% CO).
The following four results are summarizedfrom Table 1.
(i) The addition of 1 % of O2 or CO to theambient argon resulted in notable elevation (asmuch as a factor of 35; 1.8 x 10 16 at • cm- 3) of theTable 1. Concentrations of carbon, boron, and oxygen in GaAs crystals grown in
Different ambiences.
Impurity concentration atoms cm- 3
Sample No.

Atmosphere*

A

Ar

B

Ar+1%OzC

Ar + 1%CO

D

Ar + 1%CO

Solid fraction**

0.17
0.64
0.14
0.76
0.1
0.77
0.17
0.78

CarbonBoron(x lOIS)( x 10 16 )Oxygen(x 10 15 )

0.93
0.51
16
18
6.4
6.4
6.0
6.1

2.5
1.9
3.6
3.4
1.7
1.5
2.8
1.9

1.9
3.4
1.8
3.0
3.1
4.3
5.7
5.2

* Initiation time of O2 or CO addition to Ar: Band C, initiation of crystal pulling(seeding to the melt); D, initiation of heating.
* * The two different values for each sample correspond to the top and bottom of theingot.

108

Y. Itoh, et al.

C concentration, a very slight increase in the 0content, and no clear effect on the B concentration.
(ij) Carbon is regarded as being introduced tothe melt as CO formed by the reaction of additional O2 and the graphite heater because thecarbon concentration of Sample B was muchhigher than that of Sample C (2C + O2 ~ 2CO) .
(iiij The correlations between the concentration of each impurity and the solidified fraction
were: (a) for C, no clear dependence (nearly
constant for the most part); (b) for B, a slightdecrease with the solidified fraction; and (c) for
0, an increase with the solidified fraction.
(iv) Different from C and 0 in silicon,S) no
clear correlation was observed between theirconcentrations in GaAs and the CO content of theambient atmosphere during crystal growth.
Further studies with more variety of samples
are in progress, to obtain clearer information
about the behavior of C, B, and 0 in the crystal

growth and their effects on electronical properties of GaAs.
References
1) L.B. Ta, H.M. Hobgood, A. Rehatgi , and R.N.
Thomas: ]. Appl. Phys., 53, 5771 (1982).

T. Nozaki, Y. Itoh, Y. Ohkubo, T. Kimura, and H.
Fukushima: Jpn. ]. Appl. Phys., 24, L801 (1985).
3) Y. Itoh, Y. Kadota, T. Nozaki, H. Fukushima, and K.
Takeda: Jpn. ]. Appl. Phys., 28, 210 (1989).
4) Y. Kadota, K. Sakai, T. Nozaki, Y. Itoh, and Y.
Ohkubo: Semi·Insulating III -V Materials, Ohmusha,
Tokyo, p. 201 (1986).
5) L.c. Wei, G. Blondiaux, A. Glovagnoli, M. Valladon,
and lL. De: Nucl. Instrum. Methods B, 24/ 25, 9992)(1987).
6) T. N ozaki:]. Radioanal. Chem ., 72, 527 (1982).
7) H. Fukushima, T. Kimura, H. Hamaguchi, T. Noza·ki, Y. Itoh, and Y. Ohkubo:]. Radioanal. Nucl. Chem.
Artie., 112, 415 (1987).
8) Y. Endo, Y. Yatsurugi, Y. Terai, and T. Nozaki: ].
Electrochem. Soc., 126, 1422 (1979).

109
RIKEN Accel. Prog. Rep. 22 (1988)

111-3-2.

Profiling of Light Elements in the Surface Layer of Solidby Means of the Elastic Recoil Detection
Q. Qiu, E. Arai, * M Aratani, M. Yanokura, and R. Imura

Using a 50-MeV Ar4+ beam from the RILAC an
ERD experiment has been performed to profile
the depth distributions of light elements implanted into silicon wafers. Two points were aimed to
be clarified: 1) the quality of profiling data
extracted from the ERD measurements and 2)
the choice of absorber foils placed in front of anelastic recoil detector to cut off disturbing heavy
ions such as projectiles scattered by a target.
The geometry of measurement was chosen forthis experiment as follows: the target is inclined
by 30 in respect to the beam axis. Scattered andrecoiled particles were registered with two
surface-barrier detectors placed at 52 and 3T,
respectively. The distance between the beam
spot and the detector surfaces was 13 cm. A
20-pm aluminium foil was placed in front of thedetector for recoiled particles. The beam spotwas 1.5 mm in diameter. The electric current ofbeam was of the order of 10 nA. The vacuum inthe scattering chamber was 1 X 10- 5 Torr.
Helium samples were prepared by implanting
ions into silicon wafers, where two acceleratingenergies of 20 ke V and 45 ke V were chosenconsidering the helium depth distribution and theenergy spectrum expected at the ERD measurements. The dose values of implanted helium were3 X 10 15 atoms cm- 2 and 5 X 10 15 atoms cm- 2 •Lithium samples were prepared by evaporating LiF onto silicon wafers because we havetechnical difficulties generating Li ions at the
implantation laboratory. In order to simulate a
Li-implanted sample, the LiF was covered with athin aluminium layer. We made several variations of samples to investigate the deteriorationof depth resolution due to atomic collision ofrecoiled Li in the sample and in the absorber foil:
1) substrates covered only with a 35-nm LiF
layer, 2) the LiF layer was sandwiched with thesubstrate and a 60-nm aluminium layer, 3) samples with three layers with a sequence of LiFAL-LiF-substrate, and so on.
Figure 1 shows, from top to bottom, the spec00'" Research Laboratory for Nuclear Reactors, Tokyo
Institute of Technology.

tra of particles recoiled from a blank siliconwafer, a LiF-evaporated silicon wafer, and two
He-implanted silicon wafers. Around 100 channel
each spectrum has a sharp peak from surfacehydrogen of adsorbed moisture and/or hydrocarbon from the vacuum system. The broad rise ofcounts below the hydrogen peak is supposed tobe caused by scattered projectiles which passthrough the absorber foil.
Figure 1b) shows the experimental result witha LiF sample of variation 1. It is well demonstrated that the two stable isotopes of lithium
were separated. Recoiled atoms of fluorine were
not observed. The depth distribution of Li wasassumed to have a box form with a depth of 35
nm.
When we measured the ERD spectra of hydrogen and helium implanted into the Si-wafers
using an 8-MeV I6 0 beam from the Tokyo Institute of Technology Tandem, the leak of scattered particles through an absorber foil has
caused a background below the surface hydrogen
peak. Because the aluminium absorber foil wastheoretically thick enough to stop 8-MeV I6 0 ions,
we thought that the aluminium foil had inhomogeneity in the thickness. The aluminium
foil was replaced by a Havar foil. Good results
have been obtained in reducing background andalso in improving energy resolution.
10r---.-----------a~)Blank Si Wafer

...J

b)

W

Z
Z

~
U

o

c)

Z
::J

o

U

e

He Implanted Si Wafer(45keV )CHANNElNUMBERd)1024

Fig. 1. ERD spectra. Samples are: from top tobottom, a blank silicon wafer, a LiF-evaporated
silicon wafer and two He-implanted silicon wafers.

110

Q. Qiu, et al.

1rir-------L-jF-'S-j--a----,)
8.8fJm Havart)o

CHANNEL NUMBER

512

Fig. 2. Comparison of ERD spectra observed usinga Havar-foil absorber with those using an AI-foil
absorber. a) Spectrum of recoiled Li atoms fromthe same sample as that for the measurements
shown in Fig. Ib). b) and c) spectra of particles
recoiled from an AI-LiF-Si samples, where an
8.8-,t.tm Havar foil and a 20-,t.tm aluminium foil areused as an absorber of projectiles, respectively.

Considering the range of scattered particles,
we mounted an 8. 8-JLm thick Havar foil. The
Havar foil consists of Co (42.5%) , Cr (20%) , Ni
(13%), W (2.8%), Mo (2%), Mn (1.6%) , andFe (rest). Figure 2 shows the experimental
results: Fig. 2a) represents the spectrum ofrecoiled Li atoms from the same sample as thatfor the measurements shown in Fig. Ib). The
separation between the two isotopes of Li
became poorer. Spectra of particles recoiled
from an AI-LiF-Si sample are shown in Figs. 2b)and 2c), where an 8. 8-JLm Havar foil and a
20-JLm aliminium foil are used as absorber ofprojectiles, respectively. It is obvious that thealiminium foil is better than the Havar foil for
ERD measurements using a 50-MeV Ar beam.
Although the uniformity in thickness is an important factor for absorber foils, larger straggling in
the high-Z absorber is more serious in thisenergy range.

111

RIKEN Accel. Prog. Rep. 22 (1988)

111-3-3.

Depth Profiling of Light and Heavy Elements-Application to the Studyon the Compositions of Anodic Oxide Films on TitaniumK. Tachi, M. Aratani, T. Kato, M. Yanokura,
T. Sato,* and M. Otsuka*

When elastic recoil detection analysis (ERDA)
is performed with heavy ions such as an argon
ion, it is possible to obtain the depth profiles oflight elements such as oxygen, carbon and hydrogen atoms in a spectimen by using suitable absorbers. l ) Moreover, simultaneous performanceof Rutherford forward scattering spectroscopy(RFS) makes it possible to get the depth profilesof heavy elements in the specimen. Thus the information can be obtained on the compositionin complicated specimens.
Titanium anodic oxide film of less than 1 JLm
in thickness is a kind of interference film which
produces various colors and has a high dielectric
constant. Therefore, the titanium anodic oxide
film is a promising material for color production 2 ) and for condensers.3)
Using a 50 MeV Ar4+-ion beam from RILAC,
we performed the simultaneous analysis of
ERDA and RFS in order to investigate the composition of titanium anodic oxide films preparedat various electrolysis voltages in a phosphoricacid solution (5 wt.%).
A scattering chamber (75 cm in diameter)
located at the RILAC A-I beam line was used. At
the center of the chamber, the specimens were set
up at an angle of 30° to the incident beam. Two
surface-barrier semiconductor detectors (SSD)
were arranged at an angle of 33° (SSD-l) and at
48° (SSD-2) to the incident beam. In front of
SSD-l, an aluminium foil was set up to detect
only light elements (H and 0). The thicknesses
were 10 JLm for specimens No.1 to 5 and 5 JLm forspecimens Nos. 6 and 7. The spot size of anincident ion beam was 2 mm x 2 mm on the specimen.
Figure 1 shows a typical current-voltage curvefor titanium oxidized anodically in a 5 wt.%
phosphoric acid solution. The change in thecomposition in the oxide films were investigatedat the points where the remarkable changes incurrent appeared with increase of the electrolysis voltage. The titanium plates with a purity of• Department of Metallurgy, Shibaura Institute of Technology.

99.86% were used for specimen. Conditions foranodic oxidation of specimens, ratios of oxygento titanium, and the possible structure in oxide
films for each specimen are shown in Table 1.

<{

E

20

~

z

w

a::
a::

:::J

u

o

50

100

ELECTROLYSIS VOLTAGE

150
(V)

Fig. 1. Voltage-current curve for titanium with a purityof 99.86% oxidized anodically in a 5 wt. % phosphoricacid solution. Specimens are identified by numbers.
1 07.------r----r---....---,-----.--------.--.-----"1

No.7
10

No.5

No.2

Fig. 2. Depth profiles of oxygen and hydrogen in theoxide films of the specimens of Nos. 2, 5, and 7. The
peaks at far right-hand sides indicate the surfaces of
specimens.

112

K. Tachi, et al.

Table 1.

Electrolysis conditions and analytical results of specimens.

No.

Electrolysis voltage (V)Oxide film thickness (nm)Ratio of Ti and 0

Constitution of oxide film

1
2
3
4
5
6
7

23
38
91
118
133
150
170

95
106
151
177
190
313
335

1 : 0.57
1 : 0.77: l.191 : 1. 48
1 : 1.62
1 : l. 83
1 : 2.03

TiO, Ti
TiO, Ti
Ti 2 0 3 -TiO
Ti 2 0 3 -TiO
Ti 2 0 3
Ti 2 0 3 -Ti0 2
Ti 2 0 3 -Ti0 2* Each specimen is prepared from 99.86% Ti in H 3 P0 4 (5wt. %).

Figure 2 shows the oxygen and hydrogen spectra
obtained for the specimens Nos. 2, 5, and 7 with
SSD-1, in which the peak width of oxygen indicates the thickness of the oxide film, and theratio of titanium and oxygen in the oxide film isdetermined from the peak height of oxygen.
These results indicate that the thickness of theoxide film became thicker with the increase in
the electrolysis voltage. Moreover, the composition of the film was varied from TiO to Ti 2 0 3 ,and finally to Ti0 2 •For the specimens Nos. 1 and 2, the thicknesses of the oxide films were estimated to be about
100 nm, and the structures are considered to be
mixtures of Ti and TiO. For the specimens Nos.
3, 4, and 5, the thicknesses were more than 150
nm. In the specimens Nos. 3 and 4, the compositions of the oxide films were considered to be
Ti 2 0 3 near the surface and TiO at a deep part,while a uniform Ti 2 0 3 composition was found in

the specimen No.5. However, there were thesurface and substrate oxide layers in the oxide
film of the specimen No.5, and the thickness ofthe surface oxide layer was estimated as about
55 nm. For higher electrolysis voltages, the oxidein the specimen Nos. 6 and 7 grew to thicker
beyond 300 nm. On the other hand the surface
oxide layers became thinner and the substrateoxide layers were varied to Ti0 2 • This result
proves that the substrate oxide layer is preferably varied to Ti0 2 at an electrolysis voltage
beyond a critical value.
References
1) H. Nagai, S. Hayashi, M. Aratani , T. Nozaki, M.
Yanokura, T. Kohno, O. Kuboi, and Y. Yatsurugi:
N ucl. Instrum. Methods B, 28 , 59 (1987) .
2) T. Onaka and S. Ito: Proc. 78th Conf. Metal Finishing
Soc.' jpn., p. 192 (1988) .
3) A. Miyata and M. Koyama: R ep. IPCR, 37,290 (961).

113

RIKEN Accel. Prog. Rep. 22 (1988)

111-3-4.

Behavior of a Releasing Agent Coated on a Heated Substrate
as Studied by Heavy-Ion Rutherford Scattering
I. Sugai, M. Aratani, T. Kato, * H. Kato, and M. Yanokura

Recent high-resolution measurements innuclear physics require target as pure and uniform as possible and self supporting foils of lessthan hundreds of micrograms/ per square centimeter in thickness. 1)
Self-supporting foils were prepared by following processes. A releasing agent coated by evaporation between a deposited layer and a substrate
was dissolved in water, and the deposited layer
was separated and floated on water, and thenpicked up on a target frame. The foils deposited
on a substrate at high temperature are wellknown to have improved lifetime and durability
against heavy-ion bombardment. The releasing
agent coated on the substrate plays very important roles to release the deposited layer. The
foils on the releasing agent, however, are notseparated easily from the substrate in almost
cases.
In order to investigate why the layer deposited
at high temperature can not be separated
smoothly from the releasing agent on the substrate, we applied the heavy-ion Rutherford scattering method both at backward (Rutherford
backscattering; RBS) and at forward angles. A
preliminary measurement was presented
previously.2)
We used NiCl 2 as a releasing agent. The quartz
plate was used as a substrate instead of conventional soda glass 2) because it gave rise to Na
component into releasing agent. The substrates
were vacuum-deposited with NiCl 2 of 100 Ilg / cm2in thickness and were heated to 250°C , 320°C,
and 400°C. The thickness of NiCl 2 was monitored with a crystal thickness gauge during vacuum
deposition, and weighed with an electron ultra
microbalance in dry N 2 gas in order to keep
NiCb unhydrous.
The sample were bombarded with a 50 MeV
Ar4+ beam from RILAC at an intensity of about
20 nA. Surfave-barrier silicon detectors were set
at angles of 35°, 50°, and 155° in a scatteringchamber of 1 m in diameter to measure recoiled* Present address: Toyo Seikan Company, Ibaraki,
Osaka.

light elements and to monitor argon ions scattered from the samples.
The lifetime of carbon foils were found to be
independent of the substrate in the temperature
range investigated up to 430°C, but the lifetimesof the foils of elements other than carbon were
improved by the heat treatment.
Figure 1 shows the spectra of the NiCl 2 layer
treated by heating. The upper and lower spectra
were obtained with the samples heated to 400°C
and 250°C, respectively. The amount of the Ni
'0'

el
'0 '

-J

0

11~\!n
r

10'

W

:z

:z
<.
l:

10'

,u

Ii

Vl
>-

Ni

400 e

t~rnujl

'0

:z
:::>

25 0 0 e

0

u

10'

00 '

o~o--~--~--~--m-~~

CHANNEL NUMBER

Fig. 1. Spectra of the particles scattered andrecoiled from NiCl 2 atE(Ar4+) = 50 MeV and Qlab=
50
0

•

H
10'

o

e

1

Fig. 2. Spectra of recoiled impurities of hydrogen,carbon, and oxygen from NiCl 2 on the Si0 2 substrate at E(Ar4+) =50 MeV and Qlab =35
0

•

114

1. Sugai, et at.

layer on the substrate heated at 400°C pronouncedly decreased compared with that heatedat 250°C. A CI layer is seen as two peaks in Fig.
1. The low energy-side peak of Cllayer is due tosome CI component which invaded into the substrate.
Figure 2 shows the spectra of light -element
impurities from the NiCl 2 layer and Si0 2 substrate. Peaks of hydrogen, oxygen, and carbon
are also observed. Hydrogen and carbon comefrom impurities contaminated, and oxgen ismainly from the substrate Si0 2 • The two peaksof hydrogen in Fig. 2 indicate surface hydrogenin a sharp shape and internal hydrogen in a
broad shape. The peak due to internal hydrogen
disappears at 400°C.
In conclusion, at a high temperature of 400°C
the N i layer decreases and the CI layer invades

into the Si0 2 substrate. Namely, the releasing
agent seems to decrease at 400°C by sublimationand invade into the substrate. As a result, separation ability of the foil is reduced. Thus, we foundthe mechanism of reduction of separation abilityof the foil after the heat treatment at high temperature. The heat treatment is effective toimprove the strength of foils; the heat treatment
is necessary for the preparation of selfsupporting targets. A farther investigation, however, for releasing agents is also necessary for it.
References
1) S. Takeuchi, C. Kobayashi , Y. Satoh, T. Yoshida, E.
Takekoshi, and M. Maruyama: Nucl. Instrum.
Methods, 158, 333 (1979).
2) 1. Sugai, H. Kato, M. Aratani, M. Yanokura, and T.
N ozaki: RIKEN A eee!. Prog. Rep., 20, 103 (1986).

115
RIKEN Accel. Prog. Rep. 22 (1988)

111-3-5. Cross-Check of He Profiles by ERDA Methodwith 16 0 and 4°Ar Beams
K. Kurimoto, H. Hashimoto, M. Nakajima, M. Ogawa, and M. Aratani
We investigate the hydrogen retention in stainless steel pre-irradiated with helium ions in orderto study plasma-wall interactions for fusionenergy. We have found that the hydrogen profiles are very close to the range distributions ofhelium atoms as predicted from theories. I - 3 ) We
have initiated measurements of helium depth
profiles by means of Elastic Recoil Detection
Analysis (ERDA).4) We have performed crosschecks of He profiling with two different beams,
i. e., an 8 MeV 160 beam and a 50 MeV 40Ar beam.
Two specimens of stainless steel were irradiated with 10 keY helium ions to fluences of 2 X and
4 X 10 17 He/cm2 • These fluences correspond to
those below and above the critical fluence, which
induces blistering. The third specimen was implanted with 10 ke V molecular hydrogen ionssubsequent to helium pre-irradiation with afluence of 4 X 10 17 He/ cm 2 • The range of helium is
50 nm on the basis of the calculation using the
TRIM86 5) code. The 160 beam of 8 MeV wasgenerarted by the 1. 6 MV tandem pellectron at
Tokyo Institute of Technology. The 4°Ar beamof 50 MeV was provided by RILAC. In order tomake a comparison simple, we adopted the same

geometrical configuration in ERDA. The incident angle of the beams with respect to the target
surface was 15° and an outgoing angle of recoiled
atoms was also 15° with the scattering angle of30°. This geometry was chosen to optimize thedepth resolution with an 160 beam. The geometry
was also close to the optimum condition of thedepth resolution with an 4°Ar beam.
Figure 1 shows the ERDA spectra measured
with an 160 beam for three specimens. The righthand peaks correspond to the helium profiles andthe left-hand ones to the hydrogen profiles. If we
ignore the energy dependence of the stopping
power as the first order approximation, peak
shapes give depth profiles. We observed thechange in the helium profiles depending on theirradiation conditions. The depth resolution was
estimated as an order of 10 nm, because the Figs.
I(B) and I(C) indicate double peaks. The maximum probing depth was about 120 nm due tooverlapping with hydrogen signals.
Figure 2 shows the ERDA spectra taken with
an 4°Ar beam. The spectra indicate exactly thesame trends as those with the 160 beam. Figures.
2(B) and 2(C) also show the double peaks in the
A)

(A)

7
He 2 x lol /err?

He

2 x 1017/err?

l\ .J l
B)

17

If)

~
o

:::J
U

He 4x10 /cm2

1j

C)

(C)

17

He 4 x10 /em2

H 4xl017/em2);

CHANNEL

Fig. 1. ERDA spectra measured with an 8 MeV 160
beam for stainless steel irradiated to fluences of (A)2 X 1017He/ cm 2 , (B) 4 X 1017He/ cm 2 , and (C) 4 X 10 17
He/ cm 2 and 4 X 10 17 H / cm 2 •7

He 4xld /cm2
H 4xl017/cm2.1l

CHANNEL

Fig. 2. ERDA spectra measured with a 50 Me V 40 Ar
beam for stainless steel irradiated to fluences of (A)2 X 1017He/ cm2 , (B) 4 X 1017He/cm2 , and (C) 4 X 10 17
He/ cm 2 and 4 X 10 17 H / cm2 •116

K. Kurimoto, et al.

helium distributions. The depth resolution with
an 4°Ar beam is lower than that with a 160 beam
by a factor of two to three. The maximum probing depth with the 4°Ar is about 400 nm, which isthree times larger than that with the 160 beam.
For a 50 MeV 4°Ar beam, the depth resolution
was strongly affected by the energy spread of theincident beam. This is because the beam-energy
spread is no more negligible compared with thestraggling of stopping power and the detector
resolution.

References
1) M. Ogawa, K. Saneyoshi, Y. Takagi, A. Shirota, and
Y. Suzawa:]. Nucl. Mater., 149, 247 (1987).
2) M. Ogawa, K. Saneyoshi and T. Harada: Nucl. Instrum. Methods B, 33, 768 (1988).
3) M. Ogawa, K. Saneyoshi, T. Harada, and K. Imai:
Fusion Technol., 14, 719 (1988).
4) A. Turos and O. Meyer: Nucl. Instrum. Methods B, 4,
92 (1984).
5) J. F. Ziegler, J. P. Biersack, and U. Littmark: The
Stopping and Range of Ions in Solids, Pergamon,
New York (1985).

117

RIKEN Accel. Prog. Rep. 22 (1988)

111-3-6.

Application of PIXE Analysis to Materials Sciences (I)Y. Sasa, K. Maeda, and M. Uda

Particle induced X-ray emISSIOn (PIXE)
spectroscopy has been applied to the analysis oftrace element concentrations in the specimensfrom such various fields as bio-medical,1-3)
environmental,1.4) archaeological,1.5) and geological sciences. 1•6 ) This method is excellent notably
in the quantitative measurements of heavier
elements included in the matrix composed of low
atomic number elements. These merits are
expected to be effectively utilized in the field ofmaterials science as well. We have attempted todevelop a simple and convenient data-processing
procedure sui ted for the PIXE analysis of industrial materials. As a first step, trace element
distributions on the industrial Al thin foils (~15
J.1. m in thickness) were studied.
In this study, three Al foils supplied by different companies were used as test targets, and an
NBS Al alloy (SRM 1241a) and six Al sheets(~O.l mm) containing known amounts of variable impurities were adopted as the referencematerials. The chemical compositions of thereference Al sheets were determined by ordinary
chemical analysis: atomic absorption, inductively coupled plasma atomic emission, and colorCHR NN EL NUMBER
o6

40 0
300
SOD
200
10 + -- - - - - - ' -- - - - - ' -- -- - ' - - -- - - ' - -- ----<--,
100

5

Fe

10

Jl

-l
UJ

Z
Z

II

,

Ni

10

cdI

a:
:r:

n

u

a::

UJ

a...

J

10

(/'J

I-

Z
~

0
U

2

10

,.

.

I

~".

Sr

~:j:...A:,.,..;:·f!.

Zrr---rt----,-

10

Ol+-~~~~~~~~~~~~~~~~
10 0

3

4

5

6

7

8

9

ENERGY

10

11

12

13

14

15

16

i7

18

KEV

Fig. 1. PIXE spectrum obtained from an industrial Al
thin foil; a 92 mg/ cm 2 polyethylene absorber was used.

imetric analysis. The composition of the Al alloy
was guaranteed by NBS. Target materials were
irradiated with 1.6 MeV H + ions obtained fromthe tandetron. The spot size of the ion beamfocused on the targets was 3 mm in diameter andthe beam intensities were regulated to be about
50 nA on the targets. X Rays emitted from thetargets were measured with a Si (Li) semiconductor detector through a 7.5J.1.m Be window. Highenergy X rays generated from trace amounts ofelements were detected through a polyethylene
absorber (92 mg/ cm 2 in thickness) placed
between the target and the detector in order topress down the pile-up phenomenon in the detector. Signals from the detector were stored in a
multichannel pulse height analyzer, and thenprocessed on a microcomputer and recorded onmagnetic disks.
Figure 1 shows a typical PIXE spectrum
obtained from an industrial Al thin foil. The
integrated intensity of the characteristic X-ray
peak for each component (POb ) was obtained
from the observed spectra after subtraction of
background and corrections for escape peaks,
pile-up peaks, and peak overlappings. 2 •3) To
determine the absolute concentration of minor
and trace elements, the intensity of continuous X
rays (Beon) was employed as a normalizing
parameter 2 •3 ) in place of other parameters, suchas the total amount of the incident ions and thatof the backscattered ions, both of which areconventionally used for normalization. This isbecause, under the present experimental conditions, most of the continuous X rays are emitted
from the matrices of the target materials due tosecondary electron bremsstrahlung and atomic
bremsstrahlung. 7 •S ) The intensity of the continuous X rays was estimated from the background
intensity around 4 ke V where neither escapepeaks nor the exponential tails of the characteristic X-ray peaks were detected. Here the contribution from a step-like low-energy tail was
subtracted from the observed background intensity. The normalized X-ray peak intensities (POb /Beon) were then converted into concentrations(4J by means of the theoretically calculated
X-ray yields (Yea)) and the conversion factor (k)118

Y. Sasa, et al.

estimated from the PIXE spectra of seven reference materials of known chemical compositions.
The conversion factor was determined by thefollowing procedure. The relationship between
the concentration measured by the chemical
methods CCA and the normalized peak intensity
divided by the theoretical X-ray yield N px (=(Pab / Bean) / Ycal) is illustrated in Fig. 2 for thereference materials. Here, Ycal was calculated by
a computer program 'PIXAN'9) using the ionization cro.ss section of elements 0', the stopping
powers S, absorption of X rays by an Al matrix,
and the experimental conditions including abeam -target -detector geometry.
Figure 2 indicates that the data points for Fe,
Cu, Zn, and Ga are fitted on the same line with agradient of 1.0 over a wide range of concentration. This feature gives evidence that theamounts of the continuous X rays genera ted
from a target itself correctly give the conversion
factor of PIXE intensities into chemical concentrations. That is, in PIXE analysis the element

10

2

~C

o Fe

'l Cu

:l

~
E

10

o Zn
8 Go

1

c.
c.

......
a.
'"

o

Z

10°

10- 1 L-_-l...--l...-_---L.1--!.1_ _...L-...l..-_-'---'
10°

1

10

10

2

CCA (ppm)

Fig. 2. Correlation of chemical contents eCA and normalized PIXE intensities divided by the theoretical
X-ray yield N p x ( N p x = (P Ob / B con) / Yeal) .

concentrations can be determined by
Cp x =kNpx(1)
The conversion factor k for the Al matrix
system was evaluated here to be 0.165 (counts/
J1,C) from the intersect of the ordinate of Fig. 2.
With use of this factor , the contents of Fe, Cu, Zn,
and Ga in the Al foil , whose PIXE spectrum isshown in Fig. 1, were estimated as 4700, 190, 60 ,and 140 ppm, respectively.
This study demonstrated that the continuous
X-ray background can be successfully used as anormalizing parameter for the quantitative trace
analysis, and that the conversion factor evaluated on one element can be applied to any otherelements in a series of samples of similar
matrices.
References
1) S.A.E. Johansson and T.E. Johansson: Nucl. Instrum.
Methods, 137,473 (1976) ; 1a) Proc. 1st Int. Conf. PIXEand Its Analytical Applications, Nucl. In strum.
Methods, 142 (1977) ; Ib) Proc. 2nd Int. Conf. PIXEand Its Analytical Applications, Nucl. Instrum.
Methods, 181 (1981) ; Ie) Proc. 3rd Int. Conf. PIXE and
Its Analytical Applications, Nucl. Instrum. Methods
B, 3 (1984) ; 1d) Proc. 4th Int. Conf. PIXE and Its
Analytical Applications, N ucl. Instrum. Methods B,
22 (1987).
2) M. Uda, K. Maeda, Y. Sasa , H. Kusuyama, and Y.
Yokode: Nucl. Instrum. Methods B, 22, 184 (1987).
3) K. Maeda, Y. Yokode, Y. Sasa, H . Kusuyama, and M.
Uda: Nuel. Instrum. Methods B, 22, 188 (1987).
4) K. Maeda, Y. Sasa, M. Maeda, and M. Uda: Nucl.
Instrum. Methods B, 22, 456 (1987).
5) Y. Sasa, M. Maeda, and M. Uda: Nucl. Instrum.
Methods B, 22, 426 (1987).
6) H. Yabuki, A. Okada, S. Yabuki, K. Maeda, Y. Sasa,
and M. Uda: RIKEN Aeee!. Prog. Rep., 19, 119 (1985).
7) K. Ishii, S. Morita, and H. Tawara: Phys. Rev. A, 30,
2278 (1984).
8) K. Ishii and S. Morita: Phys. Rev. A, 33, 3018 (1986).
9) E. Clayton: PIXAN: The Lucas Heights PIXE Analysis Computer Package, AAEC/ M1l3, Australian
Atomic Energy Commission (1986).

119

RIKEN Accel. Prog. Rep. 22 (1988)

111-3-7.

Multielement Analysis of Human Spermatozoa by PIXE
K. Maeda, Y. Sasa, H. Kusuyama, K. Yoshida,* and M. Uda

Much attention has been paid to the elementary compositions in biological organisms inorder to obtain information for the elucidation of
the mechanisms and diagnosis of diseases. PIXE
(particle induced X-ray emission) spectroscopy
has a great potential for such an investigation,
because of its ability to analyze multiple elements simultaneously with high sensitivity without tedious chemical pre-treatments. We havecontinued a study on the application of PIXE tomedical science. 1- 4) We have used this method foranalysis of human spermatozoa, expecting theunderstaning of the roles of trace elements infertilization.
Seventeen semen samples were taken from ten
patients who were afflicted with infertility.
Later, three of these patients have proved to benormal. A part of each semen sample was used
for determination of the bio-medical qualities ofTable 1.

Semen qualities and concentrations of elements contained in human spermatozoa.
Concentration of element in spermarozoa (ppm in dry weight)

Semen quality
Patient

Volume Density Motility Trans·
ferrin

tKI
tTA
tSH
tSH

KO
WA

HO
YO
YO
YO
IS
IS

KU
KU
SI
SI
KA

(m!)

( X1Q6/ m[)

(%)

3.2

88
74
51
77
70
120
90
22
32
60
20

80
70
50
70
70
60
60
20
20
50
20
10

2.4

2.0
1.2
3.0
3.8
3.8
2.0
2.2
2.0
2.4
1.8
4.6
4.0
1.3
1.8
3.0

22

1.2
0.77
0.30
6.0
38

semen, such as a spermatozoon density (1m!), amotility of spermatozoa in semen (% motile
cells) , and a concentration of transferrin (a kindof protein which serves as a carrier of iron) insemen (ug / m!). Spermatozoa were separated
from seminal plasma by centrifugation and washed three times with distilled and deionizedwater. The washed spermatozoa were depositedon 0.5 Jim-thick Microfilm ((H 9 C5 0 3 ) n) , dried ina vacuum desiccator, and used as targets for the
PIXE analysis. The thickness and the area of thetarget samples were o. 3-3mg/ cm 2 and 0.1- 0.4
mm 2 , respectively.
A beam of l.6 MeV H+ ions obtained from thetandetron was used as an excitation source. The
beam was regulated to a 3 mm diameter spot on
the target by mean of a graphite collimator. X
rays emitted from the target were detected witha Si (Li) detector through an X-ray absorber

o
40
20
30

o

P

S

CI

K

Ca

Fe

Zn

Ti

V

Cr

Mn

Ni

Cu

Se

Br

(jig/ m!)

80
78
27
37
41
23
25
23
60
70
27
25
160
133
30

9,690 3,800 2,490 6,340 1,960 19 2,170 < 3
3
4 <2 46
6
7
25,700 7,680 1,580 2,110 1,300 56
860 < 3 < 3
3
3 <2
4
3 <2
20 ,100 6,580 2,920 2,600 1,230 54 1,630 <10 <10 118
5 13 < 7 < 720,1007 ,1502,9003,3701,030501 ,700
3
3
3
5
9
3 14
21,700 7,520 1,740 3,750 1,040 58 1,330 1045
4 <5
9 <5 <6
24 ,3006 ,7002,6103,8801,040681 ,130 6 < 3
5
6
4
7
3
16 ,000 4, 940 5,920 3,430 1,710 39 1, 370
2
3 <2
4
3 <4
8
12 ,600 1,650
910
810 6,950 13 1,100 < 3
4
2
6
<3 <3
4
17 ,000 4,110 1,310 1,980 4,690 32 1,130 < 3
3
3
3 <2
2
3
3
8,320 2,090 3,740 3,180 2,430 20
790 < 4 3
<3
3
3 <4
5
12 ,700 8,320
730 3,780 3,680 121 3,840
8
6
8
8 18
9 18
17 ,700 10 ,700 1,210 4,100 2,160 82 2,810
7 <4
9
6 13
7 11
6,670 6,780 3,220 3,580 1,250 16 2,090 < 9 < 8 < 7 < 9 <10 < 9 <27 <10
10,300 6,040 5,920 6,460 2,240 40 2,90058674 14 < 6 15
10,200 3,270 6,680 3,300 1,110 14
850
<2
2
2
5
8 <2
9
10,100 3,140 4,820 4,560 1,240 48
560 < 44
6
2 17 27 < 3 13
15,000 4,540 3,300 3,210 2,870 27 1,990 < 4 < 3
3
4
4
5
3

t normal.

• Saitama Medical Center, Saitama Medical School.

120

K. Maeda, et al.

made of l. 5 ,urn thick polypropylene or 0.5 mm
thick polyethylene film. The details of the dataprocessing procedure were described elsewhere. 1,2)
The results are summarized in Table 1
together with the semen qualities. The concentrations of the elements in the samples were estimated by comparison with a calibration curve

obtained from the reference samples with known
compositions.1,2) To determine the absolute concentrations, the intensity ratios of the characteristic X-ray peaks to the background continuum!}
were adapted. Here the intensities of the continuous X rays were integrated over the energy
range from 4 to 10 ke V to get better statistics.

•

(0)

-

•• spermatozoa
o seminal plasroo

100

•

(b)
4000

•

~
~

~

•

50

•
•

•

•

•
•
5000
S (ppm)

10000
S (ppm)Fig. 1. Concentrations of iron (a) and zinc (b) as a function of that of sulfur: ., the observed data on
spermatozoa; 0 , the observed data on seminal plasma (estimated from the PIXE spectra reported in Ref.
4) . Straight lines show the average concentration ratios (Fe/ S and Zn/ S) obtained from the observed dataon spermatozoa.

As shown in Fig. 1 (a), a linear relationshipwas clearly recognized between the sulfur content and the iron content of the spermatozoa,
although 'strong correlations could not yet befound between the semen qualities and element
concentrations in the spermatozoa. Zinc also
seemed to move along with sulfur (see Fig. 1(b)). These results suggest that the human spermatozoa contain proteins containing a large
amounts of Fe-S and Zn-S components.
The work concerning trace elements in semen
and seminal plasma has been reported in many
papers. However, there is little information on
the trace elements in spermatozoa. This may bepartly due to the fact that trace-element analysis
by analytical techniques commercially available
requires large amounts of samples. PIXE needs
very small amounts of samples (10- 9 -10- 16 g). In

addition, by use of this method, it is possible todetect fugacious elements such as sulfur, chlorine
and bromine together with other elements simultaneously. Thus, as can be seen from the examples presented here, PIXE is a promising tool forinvestigating the mechanism of fertilization.
References
1) M. Uda, K. Maeda, Y. Sasa, H. Kusuyama, and Y.
Y ok ode: Nucl. Instrum. Methods B, 22, 184 (1987).
2) K. Maeda, Y. Yokode, Y. Sasa, H. Kusuyama, and M.
Uda: Nucl. Instrum. Methods B, 22, 188 (1987).
3) H. Kusuyama, K. Okada, T. Kawai, K. Maeda, Y.
Sasa, and M. Uda: Traee Met. Metab. (in Japanese),16, 51 (1988).
4) K. Maeda, Y. Sasa, H. Kusuyama, K. Yoshida, M.
Maeda, and M. Uda: RIKEN Aeeel. Prog. Rep., 17,
127 (1987).

121
RIKEN Accel. Prog. Rep. 22 (1988)

111-3-8.

Mossbauer Emission Spectroscopy of 57Fe Arising from 57Mn

Y. Watanabe, M. N akada, K. Endo, Y. Kobayashi, H. Nakahara, * H. Sano, *K. Kubo, K. Mishima, Y. Sakai, T. Tominaga, T. Okada, K. Asai,
N. Sakai, 1. Kohno, M. Iwamoto, and F. Ambe
Mossbauer emISSIOn spectroscopy offers
unique information concerning extremely dilutedefect atoms in solid. Literature contains a large
number of emission spectra of 57Fe produced by
the EC decay of 57CO in various matrices. Little
attention has been paid, however, to anothersource nuclide of 57Fe, 57Mn.l) The short-lived
nuclide (l. 45 m) undergoes fi-decay, about 80%
of it decaying directly to the 14.4 ke V Mossbauer level of 57Fe. EC decay is well-known toresult in appreciable damage around the decaying atom due to the Auger process following it.
In the case of fi -decay, on the other hand, theaftereffects are usually not serious and often an
increase in the oxidation number by one is induced. Manganese can take oxidation states up
to 7+ in ordinary solid state chemistry, which is
not observed in cobalt. It is expected from thesefacts that an unusually high-valent iron species
could be detected after decay of 57Mn in an
appropriate matrix. So far as we know, there
have been no investigations with such an object
in view. In search of such possibilities, we intend
to use a 57Mnn+ beam, which will shortly be* Faculty of Science, Tokyo Metropolitan University.

available from the ring cyclotron.
This year, we started a series of preparatory
experiments using the 54Cr(a, p)57Mn reaction
by means of the 160 cm cyclotron. A target transportation system for this purpose was designed
and constructed as described in a separated
paper of this volume. 2) It was installed in aIm
diameter scattering chamber at the #1 beamcourse of the cyclotoron. We have successfully
observed the emission spectrum of 57Mn
produced in 54Cr metal and 54Cr 2 03 with the target transport system, a piezoelectric bimorphtransducer developed by one of the authors (N.
S.),3) and a Si(Li) detector. Experiments on otherchrominum compounds are in progress.
References
1) R. S. Preston and B. J. Zabrabsky: Phys. Lett. A, 55,
179 (1975).
2) Y. Ikegami, K. Nishi, Y. Watanabe, K. Endo, K.
Kubo, M. Iwamoto, and F. Ambe: This Report, p. 152.
3) N. Sakai, F. Ambe, and K. Asai: RIKEN Accel. Prog.
Rep., 21, 92 (1987).

122

RIKEN Accel. Prog. Rep. 22 (1988)

111-3-9.

99Ru Mossbauer Spectroscopic Studies of Heusler Alloys
Y. Kobayashi, M. Katada, R'. Sano, * T. Okada,K. Asai, M. Iwamoto, and F. AmbeIn this period, 99Ru Mossbauer spectroscopy
was applied to a series of ordered Heusler alloys. They are a ternery system consisting of
ruthenium, iron, and silicon with a chemical
formula RuxFe3-xSi, so that the ruthenium
atoms in this system are considered to substituteiron atoms of a collinear ferromagnet Fe 3Si . 1) It
is expected that the application of 99Ru Mossbauer spectroscopy is very significant for the
elucidation of the complex magnetic behavior ofthis system.
Powdered Fe (99.999%) , Ru (99.99%) , and Si(over 99.99%) were mixed in an appropriate
proportion, pressed into a pellet, and then melted into an ingot in an argon-arc furnace. The
powder X-ray diffraction patterns of annealed
samples showed that they are essentially in asingle phase with a cubic L2J Heusler structure.
Mossbauer spectra of 99Ru were measured with
99Rh in Ru metal by means of a conventional
spectrometer. The source nuclide, 99Rh (T1/ 2 =15.0 d) , was produced by irradiating a target of
97% enriched 99Ru metal powder covered with an
80 /lm Al foil with 12 MeV protons accelerated
by the cyclotron. 2)
The Heusler structure has four kinds of latticesites designated as A, B, C, and D (Fig. 1). Ina typical compound Fe3Si, Fe atoms occupy the
A, C, and B sites, A and C being equivalent toeach other.

y'""""".......... '

,/

./

y

...........

: ,~ ------ ::::d¥-- -----~~'•

Fig. 1.

A

0 C

()S

()D

Unit cell of the Heusler structure. ,* Faculty of Science, Tokyo Metropolitan University.

The 99Ru-Mossbauer spectrum of RuFe 2 Si observed at 5 K, shown in Fig. 2, has a hyperfine
structure with little asymmetry; this means thatthe origin of the hyperfine splittings is only
magnetic. The observed spectrum could be hardly analyzed with one set of magnetically split 18
lines and satisfactory fitting required two suchsets. The hyperfine magnetic fields at 99Ru forthese two components are 290 and 215 kOe,
respectively, and the intensity ratio of the former to the latter is about 1. 8. Each of these twocomponents is considered to correspond to Ru[A, C] or Ru [B].

~

~

I 00

~-:;...i.:>}~:'<":i-"~"r~~:'-;,~~

z

'

::

..
'

..

. ~ "". :.: ,~/' .

~

-

."

I::
V1

•

~

'"/.,"
.'

z

a:
a:
f-

-4

0
VELOC [TY (M M/5EC)

Fig. 2. 99Ru Mossbauer spectrum of RuFe2Si at 5 K.
The isomer shift is given against the Ru metal at
the same temperature.

The origin of Hhf at 99Ru in RuFe 2 Si is ascribedto the neighboring Fe atoms, if Ru atoms are
postulated not to have large magnetic moments
as in usual alloys. In a first-near-neighbor (Inn)model,3) it is further assumed that the dominantpart of Hhf at 99Ru originates from Inn Fe atoms
and their contribution is proportional to the
product of their number and magnetic moment.
If we take the values for Fe3Si, 1. 35 and 2.2 /lB,
as the magnetic moments of Fe [A, C] and Fe[B] respectively, the Mossbauer component
with a larger Hhf is assigned to Ru [B] and thatwith the smaller Hhf to Ru [A, C]. It is because
the Ru [B] has as Inn four A and four C sites
both occupied by Fe atoms and Ru [A, C] has
as Inn four B and four D sites, only the former ofwhich are occupied by Fe atoms. If we adopt thismodel, the present 99Ru-Mossbauer study is con-

Y. Kobayashi, et al .

eluded to show that Ru occupy both [A ,C] and[B] sites, but the latter preferentially.
More detailed discussion will be described
elsewhere along with the results of 57Fe Mossbauer spectroscopy and magnetization measurement .

123

References
1) V.S. Patil, RG. Pillay, A.K. Grover, P.N. Tandon,and H.G. Devare: Solid State Commun., 48, 945 (1983).
2) Y. Kobayashi, M. Katada, H. SanD, T. Okada, K.
Asai, N. Sakai, S. Ambe, and F. Ambe: Hypeifine
Interact., 41, 487 (1988).
3) V.A. Niculescu, T.]. Burch, and ].1. Budnick:]. Magn.
Magn. Mater., 39, 223 (1983).

124
RIKEN Accel. Prog. Rep. 22 (1988)

111-3-10.

Mossbauer Study of Organic Ruthenium Clusters
Y. Kobayashi, M. Katada, H. Sano, * T. Chihara,
H. Yamazaki, T. Okada, and F. Ambe

Organic metal clusters exhibit interesting
properties characteristic of both mononuclear
metal complexes and metals. Application of
Mossbauer spectroscopy to such compounds isvery attractive, since it provides useful information concerning the electronic state of metals
which is inaccessible by other spectroscopic.methods. Quite recently, we started a 99Ru
Mossbauer study on a series of organic ruthenium clusters. This report describes the preliminary result on the first sample of our study,[PPNJ [RulOC (CO) 24J (PPN = (PPh 3 ) 2N) .
The preparative method of the cluster and its
characterization by other techniques will be reported elsewhere. 1) Its Mossbauer spectrum wasmeasured at 5 K using 99Rh (T =15.0 d) producedby the cyclotron. The details of the measurement were essentially the same as described in
our previous paper. 2)
The spectrum given in Fig. 1 is constituted
apparently with a single line, but computer
analysis revealed the existance of a certain structure. The curve drawn in Fig. 1 is the result of
tentative fitting by assuming only one kind ofruthenium atoms with a unique electric quad-* Faculty of Science, Tokyo Metropolitan University.

-40
VELOC I TY (MM/SEC)

Fig. 1. 99Ru Mossbauer spectrum of [PPNJ [RuIOC(CO)24J (PPN;(PPh3)2N) at5K. The isomer shift
is given relative to metallic ruthenium.

rupole field. More detailed analysis and interpretation will be given in the next volume of thisprogress report along with the experimental
results on other clusters.
References
1) T. Chihara, R. Komoto, K. Kobayashi, H. Yamazaki,
and Y. Matsuura: Inorg. Chem., 28, 964 (1989).
2) Y. Kobayashi, M. Katada, H. Sano, T . Okada, K.
Asai, N. Sakai, S. Ambe, and F. Ambe: Hyperfine
Interact., .41, 487 (1988).

125
RIKEN Accel. Prog. Rep. 22 (1988)

111-3-11.

y-Rays Perturbed Angular Correlation of !lImCd in CdO
Cd(OH)21 and a-Fe(2 at.% Cd)203

I

Y. Ohkubo, S. Ambe, T. Okada, F. Ambe,
K. Asai, Y. Kawase,* and S. Uehara*
Perturbed angular correlations (PAC) were
measured for the lllCd 5/2 + level (tl / 2 = 85 ns)
mostly by using lllIn (tl/2 = 2.8 days), which
decays by electron capture (EC) to the excitedstates of lllCd. It is well known, however, thatfor insulators lllIn-PAC is strongly influenced by
the excited electonic states produced by EC andthe subsequent Auger process. This phenomenon, so-called aftereffects of EC, is generally
thought to be undesirable in applying PAC tosolid state physics or chemistry because thehyperfine frequencies are widely spread usuallyto the extent that no anisotropy can be observed.
We aim to apply PAC to solid state physics andchemistry by using short-lived lllrnCd (tl/2 = 48.6min), which decays by isomeric transition andthus is free from the aftereffects accompanying
EC . We are establishing a radiochemical procedure to separate no-carrier-added lllrnCd from ana-irradiated palladium target. In the present
preparatory work, lllrnCd with a carrier was
produced by neutron irradiation and PAC oflllrnCd in CdO, Cd(OH)2 and a-Fe(2 at.% Cd)20 3 were measured.
It is expected from the crystal form of eachcompound that i) there is no extranuclear perturbation in CdO, ii) lllrnCd in Cd(OH)2 feels anaxially symmetric electric field gradient and iii)
lllrnCd ina-Fe (2 at. % Cd) 20 3 feels both an axially symmetric electric field gradient and a hyperfine magnetic field at room temperature and only
an axially symmetric electric field gradient
above the N ~el point ~ 960 K. The measurements on the first two compounds were intended
to check the whole experimental procedure andapparatus. Our main interest was in the measurement on the third sample.
The above compounds containing about 0.5 mg
of isotopically enriched (94 %) lloCd were
irradiated for 5 min at a thermal neutron fluenceof 1.93 X 10 13 s- lcm- 2 in the Kyoto University
reactor. A PAC spectrometer with a four BaF 2(1.5 intP X 1 in) detector arrangement consisted• Research Reactor Institute, Kyoto University, Osaka.

of specially designed digital modules and commercially available analog modules, and wasconnected to a personal computer. The coincidence counts for detector combinations of 90 and
180 degrees were measured simultaneously as afunction of delay time between the emissions of
the 151 and 245 ke V y-rays. Total measurement
time for each experiment was about 1 hour.
The measured time-differential PAC (TDPAC) spectra A 22 G22 (t) are shown in Fig. 1. For
CdO, no significant perturbation was observed,
as expected from its crystal form, A 22 G 22 (t =0)=A22~0.1 (Fig.1(a)). For Cd(OH)2, theperturbation characteristic of an axially sym0.15(al,

1 ch = 1 ns

0.1
'I
I

II
III I IIII 1I1l11 1 ,' ! I II
11"11111111111111111111

0.0 5

1111111111111 II

0

0.1 ~
N
N

0.0

11'1

5 I

N
N

-<

II

11III

\11" ''''' '11'1111'1111
'

0

II

(bl

I

:;:t:)I I

I 1111111\

I
1111111\IIIIIIi1IIIIIIIIIIIIVII

IIII

0.1 ::(el0.0o

5 IIIIIIIIIiI11111111111111111111111111Ii1lill\llllilllll"IIII//////1111111

o

50

100

150

200

250

300

Channels

Fig. 1. TDP AC spectra of lllCd (5/2 +) in CdO(a) and Cd (OR) 2 (b) measured at room temperature, and a-Fe (2 at. % Cd) 20 3 (c) at 1,023
K.

126

Y. Ohkubo, et al.

metric electric field gradient was observed. The
frequency was about 70 ns, which is in conformity with the value reported by another group, 1)
but the amplitude we observed was about a halfof the value of the group (Fig.1 (b)) . For a-Fe (2at. % Cd) 20 3 , measurements were made at room
temperature and at 1,023 K. Identical TDP AC
spectra were obtained at both temperatures. The
latter temperature was chosen to be higher thanthe Neel point ~ 960 K, above which only axially symmetric electric field gradient is expected
to cause perturbation . However, almost no
anisotropy was observed in the spectra, irrespective of annealing done after the neutron
irradiation (Fig.1 (c)). The observation indicates that IllmCd was not in the regular site ofiron in the matrix. This is in striking contrast to

the result on a-Fe (111In) 20 3 obtained by using
no-carrier-added lllIn. 2 - 4 )We plan to study further on no-carrier-added
IllmCd embeded in a -Fe 2 03 and other various
compounds, using the natpd (a, xn) IllmCd reaction and a radiochemical method for separating
lllmCd from palladium irradiated at the cyclotron.
References
1) R.S. Raghavan, P. Raghavan, and J.M. Friedt: Phys.

Rev. Lett., 30, 10 (1973).
2) K. Asai, F. Ambe, S. Ambe and H. Sekizawa: J Phys.
Soc. jpn., 53, 4109 (1984).
3) F. Ambe, K. Asai, S. Ambe, T. Okada, and H. Sekizawa: Hyperfine Interact. , 29, 1197 (1986).
4) K. Asai, F. Ambe, S. Ambe, T. Okada, and H. Sekizawa: Hypeifine Interact., 34, 277 (1987).

127
RIKEN Accel. Prog. Rep. 22 (1988)

111-3-12.

Preparation of No-Carrier-Added lllmCd for the Measurementof y-y Perturbed Angular Correlations. Ambe, Y. Ohkubo, M. Iwamoto, and F. Ambe
Commercially availablelllIn is one of the mostconvenient source nuclides for y-y perturbed
angular correlation (PAC) studies. This nuclide,however, is known to give rise, in insulators, tothe smearing-out of PAC patterns due to theaftereffects of its EC decay to IllCd, providing
little information on the electronic state oflllCd. l,2) On the other hand, lllmCd (half-life: 48.6min), another lllCd-PAC source nuclide, undergoing isomeric transition causes no serious aftereffects. The nuclide is produced by the llOCd (n,y) lllmCd reaction in a reactor, but is not obtainedin a state free from non-radioactive cadmium. In
this study we have established a procedure ofpreparing no-carrier-added lllmCd by using thecyclotron, that is, by the Pd (a ,xn) lllmCd reaction. The pH dependence of adsorption ofdivalent Cd* ion onto a-Fe 203 and its coprecipitation behavior with ferric hydroxide were also investigated for the PAC studies
on the adsorption structure of lllCd2+ on the £1'Fe 2 03 surface and the defect structure of lllCd 2 +in the bulk a-Fe 203'
Pd foils (8 ~m) were irradiated with 40 MeV aparticles accelerated in the cyclotron. Since a
irradiation produces I07Cd (half-life: 6.5 h) alongwith lllmCd, we used both nuclides as tracers;
thus, we refer 11lmCd and l07Cd to as Cd *.
The Pd target was heated in a quartz tube witha glass cold finger under a rotary pump vacuum(8-11 Pa). The sublimation yield of Cd* wasdetermined in order to find the optimal temperature for expelling Cd* from the target by measuring the y rays from Cd* with a Ge detector
installed under a furnace. Stepwise elevation ofheating temperature showed that marked sublimation of Cd* starts at around 1,000°C. Above 1,
050°C Pd was markedly sublimated. We, therefore, adopted 1,050°C as the temperature
for routine sublimation. We found that at
1,050°C more than 90% of Cd* was sublimated in
60 min and trapped on the cold finger.
Most of the Cd* deposited on the cold finger
with a minute amount of metallic Pd was dissolved in hot 1 : 1 nitric acid in 5 min. Palladium
and radioactive Ag produced by the (a, pxn)

~ 1OOI..---------f"I=o....------n---€~

it
"0

U

6

50

t:

o

:;:;
C.
\...

~

~

0~~~-7_~~~~
2

4

10

12

14

pH

Fig. 1. Adsorption of no-carrier-added divalent Cd* onto
a-Fe 2 03 from a 0.5 mol· dm- 3 NaN0 3 solution.

reactions were sublimated and dissolved
together with Cd* and completely eliminated by
0.01 % dithizone-CCl 4 extraction after the solution was mixed with a dil. N aOH solution to be
pH 2.0.
In the adsorption experiment, 30 mg a-Fe203
powder was added to a 15 cm 3 Cd* tracer solution and the suspension was shaken for 1 h atroom temperature. Adsorption of divalent Cd*
onto a-Fe 2 03 was observed above pH 6.5,
increasing with pH to be virtually 100% above
pH 9 (Fig. 1). The adsorption curve is typical ofhydrolyzable metal ions. Irrespective of the different pH of adsorption, no thermal dissociationof the adsorbed Cd* from a-Fe203 was detectedon heating at 600°C for 20 min in air.
After addition of the Cd* tracer to a 40 cm 3
ferric nitrate solution (0.02 mol • dm- 3) , the Cd*ions were coprecipitated with ferric hydroxideby adding N aOH or NH 4 0H. More than 60% of
Cd* was coprecipitated, but about a half of Cd*
was lost when the sample was heated at 800°C for
30 min in air.
The lllmCd on the surface and in the bulk of
a-Fe203 will be subjected to PAC measurementin the near future.
References
1) P. Lehmann and J. Miller: J. Phys.

Radium, 17, 526(1956) .
2) H. Haas and D.A. Shirley:]. Chem. Phys., 58, 3339
(1973) .

128
RIKEN Accel. Prog. Rep. 22 (1988)

111·4.
1.

Radiation Chemistry and Radiation Biology
High-Density Excitation by Heavy Ion: Techniques and Measurement of
the Fast Emission Decay of BaF 2 Single Crystal
K. Kimura, T. Suzuki, K. Watanabe, K. Uehara, and H. Kumagai

Ions of energies lower than few e V / amu may
induce many particular elementary processes incondensed matter, e.g., charge transfer, collective excitations, wake-field, and comboy-electron
effect. These processes may conceal possibilities
to give rise to chracteristic radiation effects tomatter, though such effects have not yet beenfound. However, a principal part of radiation
effect in condensed matter is considered to behigh density excitations, because primaly collisional events, as well as processes aforementioned, lead to excited states of an outermost
shell via electron cation recombination and cascading internal conversion. The maximum
energy-deposition by heavy ion amounts to aslarge as thousands electron volt per Angstrom at
an ion track termination. This may imply that
only excited states are contained in a track termination. Therefore, it may be possible that theconcentration of excited states exceeds that of
the ground state near the track termination, andhence more than two excited states can collide in
their lifetimes. Our previous work shows thatshort-lived free excitons of few ps in alkali
halides collide with each other to give an LETdependent ratio of yields between self-trapped
excitons.l) Thus, the decay modes of excitedstates are in general different from those of
spontaneous ones, and lifetimes are shortenedwith density. Decay measurement is one of themethods to investigate the effect of high-density
excitation by heavy ions. For this aim, we developed equipment for subnanosecond emissiondecay measurement which can operate not only
without any improvement of an accelerator but
also operate using radio isotopes as an irradiation source. 2 ) The equipment was applied to asingle crystal of BaF2, which has recently
attracted special interest, because of its extraordinarily fast emission decay at 2,200 A.3)
We adopted a single-ion hitting and singlephoton counting technique developed previous-

Ar4+~--~~~--------~

Fig. 1. A block diagram of the detectors and circuit. A
cryostat was set as described in Refs. 3,7, and 12. Hostand for the static magnetic field; MCP, a multichannel plate; TAC, a time-to-amplitude converter;
CFD, a constant fraction discriminator; OMA, a opticalmulti-channel analyzer.

ly, I ) and improved detectors for ions and photons
at same time. As shown in Fig. 1, an incident ion
passes through orifices of two coaxial coppercy linders before hitting a target. A thin carbon
foil of 10 micro g/ cm 2 is attached on the entrance
orifice (0.5 mm in diameter) of the outer cylinder. Secondary electrons emitted from the carbon foil were accelerated to 2 ke V between theouter and the inner cylinders, bent by 90 degree
by a magnetic field, monochromatized by cut off
with an orifice (1 mm in diameter), and excited
MCP. This system was termed FASD (fastsecondary-electron detector). Other timing pulses
were generated by single photon detection usinga photomultiplier (MCP-installed Hamamatsu
R1564u of a rise time of 220 ps).
As shown in Fig. 2, a time integrated spectrum
shows only one broad peak at about 3,100 A, but
no prominent peak at 2,200 A, in contrast withthe case of electron and photon irradiation. 4,5) Ashoulder could be recognized near 2,200 A atmost by a plot of the rises near time o. Thus, aK. Kimura, et al.

40001.;---t---~"""'-'::::--""""'

time/nsFig. 2. Time resolved spectra of N -ion irradiated BaF 2
at room temperature. Time integrated spectrum measured by a monochromator and OMA is also superposed at 80 ns.

COUN 3Fig. 3. Logarithmic plot of emission decay of BaF 2
2,200 A emission; a straight line is the best fit of theslow component.

fast decay component at 2,200 A is suppressed inintensity with ion irradiation and also possibly
broadened.
A logarithmic plot of the fast decay at 2,200 A,
Fig_ 3, shows that the decay consists of two
exponentials of half lifetimes of 250 ± 50 ps and
32 ± 0 . 7 ns. The slow component is considered
due to the stray of 3,100 A emission because
resulting from the use of a band-path interference filter at 2,000 A.
The emission at 2,200 A was suppressed bylowering temperature and disappeared at 4.2 K
in contrast with alkali halides. Similar temperature dependence was observed for the intensity of
the 3,100 A .peak. Relative intensities to that atroom temperature were about 0 at 4.2 K, 0.2 at
97 K, 0.29 at 142 K, 0.34 at 188 K, and 0.67 at

129

233 K.
The emission at the 2,200 A peak is explained
to originate in a crossover transition fromvalence electron of F - 2p to an inner shellvacancy of Ba 2 +5p.3,S) The present results, thelinear and fast decay, may support this model.
The lifetimes for X irradiation 4 ) and electron
irradiations,S) however, are reported to be 600 ps
and 880 ps, respectively. It is a important problem to be resolved whether this discrepancy
between the electron or X-ray and heavy-ion
irradiation is due to LET or caused by poor
resolution. The LET dependent suppression of
the 2,200 A emission is also curious, whichcannot be explained on the basis of simple density effect such that a density of F-2p electrons islowered considerably because of high density
excitation by heavy ions, because the suppression was at maximum for alpha particles whose
LET is considerably lower than that of Ar ion. In
addition, no significant difference was recognized between 5 and 10 MeV /amu alphairradiations despite the latter's larger delta rayeffect and lower LET. The result seems to suggest that an increase in LET increases radiative
processes in a crossing manner to quenchingprocesses. Also, the result that the temperaturedependence is rather reverse to the case of alkali
halides means that formation mechanisms of freeand self-trapped excitons are completely different from those in alkali halides. Details are
discussed in Ref. 1. The formation mechanismsof excitons along with the LET effect aforementioned is a interesting problem to be solved.
References
1) K. Kimura, Y. Matsuyama, and H. Kumagai: Int.
Radiat. Chem. Phys., in press.
2) K. Kimura and M. Imamura: Phys. Lett. A, 67, 159(1978); K. Kimura, K. Mochizuki, T. Fujisawa, and
M. Imamura: Phys. Lett. A, 78, 108 (1980).
3) Yu.M. Aleksandrov, V.N. Makhov, P.A. Rodnyi, T.!.
Syreishchikova, and M.N. Yakimenko: Sov. Phys.
Solid State, 26, 1734 (1984).
4) M. Laval, M. Moszynski, R. Allemand, E. Cormoreche, P. Guinet, R. Odoru, and J. Vacher: Nucl.
Instrum. Methods Phys. Res., 206, 169 (1983).
5) S. Kubota, M. Suzuki, Jian-zhi Ruan, F. Shiraishi, and
Y. Takami: Nucl. Instrum. Methods Phys. Res., A,
242, 291 (1986).

130
RIKEN Accel. Prog. Rep. 22 (1988)

111-4-2.

LET Dependence of Cellulose Triacetate Film Dosimeter
Response for Ion Beams
H. Sunaga, R. Tanaka, * K. Yoshida, * and I. Kohno

A commercial cellulose triacetate (CTA) film
dosimeter FTR-125 has been widely used in radiation processing using electron beams andgamma rays. We examined if the dosimeter isapplicable conveniently to ion beams.
In a previous report!} on the characteristics of
CT A film dosimeter for proton beams, we foundthat the value of ~OD (difference in opticaldensities at 280 nm) per unit dose measured with
5 MeV protons, was smaller those with 8 and 15
MeV protons, suggesting LET dependence.
To study the LET dependence of CTA film
dosimeter in the high LET region, we measured
the dose responce for ion beams with different
LET, i.e., 30-MeV helium, 80-MeV carbon, and80-MeV nitrogen ions.
A CT A film of 125 J1. m in thickness and 8 mm
in width was mounted on a cylindrical holder ofa rotation type irradiation apparatus for uniform
irradiation.!} The apparatus was set at the No.2
course of the cyclotron. All samples were
exposed in vacuum.
The ion fluence was evaluated from the ratioof a total charge impinging on the sample holder
to an effective irradiation area. The doseabsorbed in a CT A sample was estimated fromthe mass stopping power of the sample by acomputer program OSCAR. We took the valuesof mass stopping power of 214, 2,120, and 3,260
MeVg- 1cm 2 for 30-MeV He ions, 80-MeV C ions,and 80-MeV N ions, respectively.
Figure 1 shows the relations between theabsorbed dose and the ~OD's in CT A samples
irradiated with various ions, in comparison withthe result obtained with 2 MeV-electrons and 5,8,
and 15 MeV protons. The K -value (defined by~OD/ I0 kGy) decreases with increasing LET,
and linear dose dependence was observed forheavy-ion beams with LET higher than that ofthe proton beams.

O. 06

~~Q
o

-0

Ql

:J

~ 0.04I~

0.02
0L.....l....LLJ..l.WL--'-.L.LLJ.J.LLJ...........L.....L..w..u..LI.L--'---'--~

10°

10 1
LET

10 2

10 3

10~

(MeV g - I cm 2 )Fig. 2. Dependence of the K -value (~OD/ I0 kGy) on
the initial LET for the various ions and 2 Me V
electrons.

Figure 2 illustrates the dependence of theK -value on the initial LET for various ions andelectrons, showing that the K -value decreases
2.0
E

J 1.5
C\J
~

.......
a 1.0
o
'<l

0.5

100

200

300

400

Dose ( k Gy)

Fig. 1.

Relation between absorbed dose and thein CT A samples irradiated with various
ions, in comparison with the results obtained with 2
MeV electrons and 5, 8, and 15 Me V protons.
~OD's* Takasaki Radiation Chemistry Research Establishment, JAER1.

remarkable with increasing LET in the region of
50-200 Me Vg- l cm 2 and that the rate of decrease
becomes low at higher LET's.
For practical ion beam dosimetry. using CTA
dosimeter, further dosimetry characterization
will be necessary for dependence of the dose
response on effective LET, the useful ranges ofabsorbed dose and LET, and the dosimetry uncertainty.
Reference
1) H. Sunaga, T. Agematsu, R. Tanaka, K. Yoshida, and1. Kohno: RIKEN A eee!. Prog. Rep., 21, 141 (1987).

131
RIKEN Accel. Prog. Rep. 22 (1988)

111-4-3.

Proton Irradiation Effects on Mechanical
Properties of Aromatic Polymers

T. Sasuga, S. Kawanishi, * M . Nishii, T. Seguchi, * and I. Kohno

For evaluation or selection of polymer materials used in space as the components and equipments of artificial satellites, knowledge about
the radiation damage induced by high energy
ions is needed. Primary experimental results on
proton irradiation effects were described in theprevious report,1) in which the changes inmechanical properties of a variety of aliphatic
polymers were studeid and compared with thoseobtained by electron irradiation. The radiolysis
yields of organic liquids are known to alter by
linear energy transfer (LET),2.3) while small or no
LET effects were observed on the aliphatic polymers between 8 Me V proton and 2 MeV electron
irradiation even though protons have LET 30
times larger than that of electrons. Our experimental resultsl} suggest that (1) there is no significant defference in crosslinking/ chain scissions
ratio, or (2) the differences in the chemical reactions in micro domains are not directly reflected
on mechanical properties.
In the present study, we carried with four
aromatic polymer films different in structuresfrom those used in the previous studyl} andcompared with the results of electron iradiation.
The polymers used were polyethyleneterephtalate (PET), polyethersulfone (PES), bisphenol A based polyarylsulfone (U-PS), andpolyarylester (U-polymer). These polymers wereobtained in a film form with 100,um in thickness.
The chemical structures are shown in Fig. 1.
(-{)-c-Q-c-o-cfi2C H)

8

0

2 n,

0
(-0-°50-0- -)-PETProton irradiation was performed with a beamof 8 MeV accelerated with the cyclotron in thespecially constructed chamber reported previously.l) The fluence rate was about 13 nC/ (cm 2s).
Electron irradiation was carried out under ahelium gas flow with a 2 MeV electron beam obtained from an accelerator at JAERI Takasaki.
The electron fluence rate was 1.07,uC / (cm 2s).
Irradiation effects were evaluated by tensile tests
at a cross head speed of 200 nm/ min at 25°C for
the specimens cut into an ASTM D-1822 typedumbbell.
The absorbed dose D (kGy) for protons wascalculated from the relation:

D = SXQ

where S (Me V cm 2/ g) is the mass collision stopping powere and Q (,uC / cm2) is the fluence. The
stopping powers were calculated by Bethe'sequation as listed in Table 1. The absorbed dose(De) in the electron irradiation was measured byuse of a cellulose-triacetate (CT A) film
dosimeter and was corrected for the stopping
powers of each polymer for 2 MeV electrons.
Table 1. Stopping powers of the polymers for 8
Me V protons and 2 Me V electrons.
PolymerPES
V -PS
V-polymer
PET

Stopping power (MeV • cm Z/ g)
for protons

for electrons

48.9
49.6
50.4
50.1

1.78
1.78
1.78
1.78

n

PES
CH3

0

(-OO¢ -=O-OO~-o-)n
0
CH3

U-PS

(~g~-c-oC-O-)~ I· -~I I

CH 3

0

=::::'"IIn

0

U-Pol y me r

Fig. 1. Chemical structures of polymers used.
* Takasaki Radiation Chemistry Research Establishment, J AERI.

Figure 2 shows the variations in the tensile
strength and elongation at break as a function of
proton and electron doses for PET. In proton
irradiation, the decrement of the tensile strengthwith dose is less and the decrement of elongation
with dose is rather larger than those for electron
irradiation. The polymer chain of PET is composed of aromatic and aliphatic units. The resultfor PET indicates that LET of radiation affects
change in mechanical properties.
The result for U -PS, which is composed of only

132

T. Sasuga, et al.

180
til
Cl.

! 160
.c

0>

c

~140
III

80

CII

== 120
III

rf!

CII
I-

c
60 .~

c

til
0>

40

g
UJ

20

o

2.0

1.0
A bsor bedodose(MGy)Fig. 2. Tensile properties as a function of dose for
PET films irradiated with 8 MeV protons ( 0 ) and2 MeV electrons

«) .

~

til
Cl.

to increase with increasing aromaticity.
Figure 4 shows the gel fraction of U-PS as afunction of dose. In electron irradiation, no gel isformed, but in proton irradiation the gel content
increases with dose. This finding shows thatcrosslinking takes place in proton irradiation.
The smaller decrement of the strength and elongation in proton irradiation than in electron
irradiation would be caused by increase in theprobability of crosslinking.
In general, radiation effects in a condensed
phase with high LET irradiation is characterizedby high density excitation and high probabilityof recombination in the supr. 2 •3 ) The results in
Figs. 2 to 4 could be interpreted in terms of theincrease in the probability of bimolecular recombination of excited molecules, like in benzene.
However, this model fails to interpret the experimental results for aliphatic polymers; the othermechanism also has to be taken into account for
the interpretation of the LET effects on polymeric materials.

!100
.c

0>

~ 80

50

d

Vi
~

60

!.

40

o

rf!

'C' 30

MeV p

o

~ 20
Qj

(!l10

o

o

2 MeV e-

o

2.0
1.0
Absorbed dose(MGy)Fig. 3. Tensile properties as a function of dose for
U-PS films irradiated with 8 MeV protons ( 0 ) and2 MeV electrons«).

aromatic units, is shown in Fig. 3. The dose
dependence for the two tensile parama ters isalmost the same up to 1 MGy in proton andelectron irradiation, but above 1 MGy thedecreasing rates of the strength and elongation
per dose in proton irradiation become less thanthose in the electron irradiation, indicating thatthe radiation effects decrease with increasing
LET. The same results also were obtained in
PES and U-polymer. From the results of aliphatic polymer 1) and PET, the LET effect seems{) _(}_---L_---L_ _ ()_

o

3

4

5

Absorbed dose(MGy)Fig. 4. Gel fraction as a function of dose of U-PS
films irradiated with 8 Me V protons ( 0 ) and 2
MeV electrons«).

References
1) T . Sasuga, S. Kawanishi , T. Seguchi. and 1. Kohno:
RIKEN Aeee!. Prog. Rep., 21, 139 (1987).
2) lW.T. Spinks and Rl Woods: An Introduction to
Radiation Chemistry, John Wiley, New York, p. 368(1964) .
3) P. Ausloos (Ed.): Fundamental Process in Radiation
Chemistry, International Publishers, New York, p.
482 (1968).

133
RIKEN Accel. Prog. Rep. 22 (1988)

111-4-4.

An Irradiation System for Biological Samples and Dosimetryat RIKEN Ring Cyclotron
I. Kaneko, T. Kosaka, T. Kanai, Y. Yamada, Y. Ikegami,
T. Watanabe, S. Watanabe, K. Nakano, K. Eguchi-Kasai,
T. Katayama, F. Yatagai, T. Takahashi, and K. Hatanaka

In a previous papar, 1) design and constructionof an irradiation system for biological samples
were described. In the present paper, a preliminary test of the system and the methods of
dosimetry at RIKEN Ring Cyclotron facility arepresented.
The beam port for biological research is composed of an apparatus for making a homogene-ous irradiation field and a beam monitoring
system. To make an irradiation field equal to thesize of a culture dish of 35 mm in diameter, awobbler scanning magnet was constructed. Theenergy of an Ar ion beam used in the present
experiment was ~26 MeV l u. The beam wasallowed to pass through a quadrupole-triplet
magnet and focussed either on a sample dishcf> 15Gauge port

Gate Valve(pneumatic)

Ti foil
20,um

cf>50

Dish

Beam ---- -+11+-- -----If~t--~~ - - H --

-

-+---

---#+II#-- ~H-+-Ilq

- .
- --

/
PPAC

I

0]

\onization
Chamber

Gauge port AI Absorbercf> 15

Fig. L Schematic diagram of the beam port for biological research.

containing a sample or on a zinc sulfide monitor(Fig. 1). The beam was focused by monitoring abeam profile on the ZnS monitor with a television camera. A beam passing through a vertical and a horizontal magnetic fields of the wobbIer magnet produced a bright circle on the ZnS
monitor because of the circular motion of thebeam due to the sinusoidal magnetic fields (Fig.
2). In homogeneous irradiation, a gold scattering
foil of 34 J1. m in thickness was inserted immediately after the wobbler magnet. The beam
showed a gaussian profile and, by its circularmotion, gave a nearly homogeneous irradiation
field when a flight path length was ~ 2 m. The
beam monitoring system is composed of aparallel-plate avalanche counter (PPAC) and an
ionization chamber. The PP AC was used forboth beam profile monitoring and measurementof the beam intensity.2) The beam profile displayed every 5 s on a CRT of a minicomputer
was found nearly homogeneous in some cases;
further improvement is required for constant

X

Time

Fig. 2. Time-dependent magnetic field of
the wobbler magnet and the circularmotion of a beam.

homogeneity. A mechanical device for exchanging Al absorbers of various thicknesses and an
ionization chamber were set outside the irradiation window located at the end of the vacuum
window (a 20 J1.m Ti foil). The ionization chamber made of two parallel aluminized Mylar filmsof 4 J1. m in thickness, which were fixed 2 mmapart, was filled with atmospheric air.
The irradiation chamber was constructed frommaterials which are not toxic to cell growth andcan be sterilized to prevent biological contaminations. Nine samples in culture dishes were set on
an aluminum holder, and each sample was successively irradiated according to the preset num-134

I. Kaneko, et al.

ber of counts of the PP AC. The temperature of
the chamber are controllable at 30- 3TC for the
optimal' growth conditions. To investigate thesynergistic action of hyperthermia and radiation,
the temperature of the chamber is adjustable in
the range of 37- 45°C within ±0.05°C. The damageof high molecular-weight molecules such as nucleic acids and protein in the cell and their repair
process can be investigated below 4°C to prevent
repair during exposure by blowing air at a desired temperature into the irradiation chamber; theair should contain 5% CO 2 to maintain desired
pH in a culture medium. For the measurement of
the oxygen enhnacement ratio and for the test in
hypoxic radiosensitizers, N 2 gas containing 5%
CO 2 , instead of air, should be used.
Comparing the beam intensities measured with

the PPAC and with a CR-39 track detector in thedish of the sample, we found that the number
density of etch pits observed on the CR-39 track
detector was in agreement with the number ofcounts of the PPAC within '""'-'10%. The Bragg
curve was successfully observed by in~erting Al
absorbers of different thicknesses with the ionization chamber whose current was normalized
to the PPAC counting rate.
References
1) I. Kaneko, K. Eguchi, T . Takahashi , and K. Nakano:Sci. Papers 1. P. C. R. , 79, 60 (1985) .
2) H . Kumagai , Y. Yamada, N. Tajima, T . Kosaka, K.
Nakano, F. Yatagai, and T . Takahashi: This Report,
p. 135.

135
RIKEN Accel. Prog. Rep. 22 (1988)

111-4-5.

Parallel Plate Avalanche Counter for Dosimetry In the
RIKEN Ring Cyclotron Biology Facility
H. Kumagai, Y. Yamada, N. Tajima, T. Kosaka,
K. Nakano, F. Yatagai, and T. Takahashi

A position-sensitive parallel-plate avalanche
canter (PP AC) was designed and constructed for
dosimetry in RIKEN Ring Cyclotron biology
facility. As shown in a separate paper!) in thisvolume, homogeneous irradiation of Ar ions was
attempted by using a wobbler magnet and ascattering foil, but beam homogeneity over thearea of a biological sample was not easily attainable. PP AC is expected to be useful to obtain
information on the homogeneity as well as on the
precise flux of the beam on a sample.
(1) Construction of PPAC
PPAC is suitable for counting very high rates
since the pulse width of its output is of several
nanoseconds. It is also suitable for detecting
heavy ions of several tens of MeV / u, because
output signals are sufficiently large but energy
loss is negligibly small, when the ions traverse
through the PPAC. As shown in Fig. 1, the PP AC
is composed essentially from an central anodefoil and two outer foils with sensitive areas of
50 x 50 mm 2 • The anode is made of 2 jim myler
foil, both sides of which were deposited with gold
to 40 jig/cm 2 in thickness. The cathodes are
made of 2 jim myler foils, one side of which was
deposited with gold to 80 jig/ cm 2 in thickness,using a mask with ten stripes. Ten gold stripes of
4.5 mm in widths, each having intervals of 0.5mm, were formed as cathodes on the foil to get
position information of the x or y axis. The
distance between the cathode and the anode was
3 mm and the anode bias of 600 V was applied
when 26 MeV / u Ar ions were used. Isobutane ofabout 6 torr was used as a counter gas.

Cathode-X

Y.10
Y.9
Y.S
Y.7
Y.6
Y.S
Y.4
Y.3
Y.2
Y.1

Fig. 1. Schematic view of two-dimensional PPAC.

.---------------1~ Analog Monitor
Discri. Monitor

PPAC

Fig. 2.

Block diagram of the electronics of the beam profile monitor.

136

H. Kumagai, el al.

Beam profile monitor
The block diagram of electronics for a beamprofile monitor is shown in Fig. 2. The output
pulses of the anode were amplified 100 times witha preamplifier and a fast main amplifier. After
discrimination of noise signals, the anode pulses
are converted to fast NIM signals and countedwith a 24 bit scaler. The total counts of the anodesignals were used to estimate doses. The output
pulses from the x or y cathode are amplifed 100
times with a preamplifier and an inverting amplifier, and are converted to fast NIM signals witha discriminator. The signals from the x axis arecounted with a 10 channel scaler for the x axis
(x-scaler), when the x signal coincides with asignal from the Y5 or Y6 cathode (Fig. 1). Thus,
the position information along the x axis (50 mm
long and 10 mm wide) is available from thenumber of counts of the 10 chennel x-scaler. The
position information along the y axis is alsoavailable from a 10 channel scaler for the y axis,
because the signals from the y axis are countedwith a y-scaler, when the y signal coincides witha signal from X5 or X6 cathodes (Fig. 1). The
beam profiles for the x and y axis are displayedon a CRT of minicomputer PC9801.
(3) Linearity between the counting rate of
PPAC and the beam intensity
To obtain a dose from the counting rate ofanode signals of PP AC, it is necessary to confirm
the linearity of the relation between a counting
rate and a beam intensity. In 1985, we cor~firmed
the linearity up to 2 X 10 6 cps by using He ionsfrom RILAC;2) however, sufficient accuracy was
not obtained because beam intensity was measured with a Faraday cup. In the present work,
we have examined the relation between the
counting rate of PPAC and an ion current froman ionization chamber. The ionization chamber
is made of two parallel aluminized myler films of
4 jJ. m in thickness fixed 2 mm apart, and is filledwith 1 atm air. Figure 3 shows the relation
(2)

II

III

I II

II

I 111111

1111..I!I.-

•
1111

I

1111

I

III

I III

I II

P"'1 II

1111

I

1

1111111I I

1111111

I

III.JCif&1l

I I
1

mff

Counting Rate of PPAC (cps)Fig. 3. Relation between the counting rate of PP AC
and the current of the ionization chamber.

between the counting rates of PPAC and ionization currents from the ionization chamber for 26
MeV /u Ar ions. We found that good linearity isheld in the range from 10 2 to 4 X 10 5 cps within ±3% errors. Electric charge produced by an Ar
ion, when it passed through the ionization chamber, was found to be 6.49 x 10- 15 C/ particle, whichis in rough agreement with a calculated result,i.e., 7 X 10- 15 C/particle. The calculation is basedon W =35 eV and 5=6.0 MeV / (mg/cm 2), where
Wand S are the W -value and the stopping
power in air, respectively, for 25 MeV / u Ar ion.
References
1) I. Kaneko, T. Kosaka, T. Kanai, Y. Yamada, Y.

Ikegami, T. Watanabe, S. Watanabe, K. Nakano, K.
Eguchi-Kasai, T. Katayama, F. Yatagai, T. Takahashi, and K. Hatanaka: This Report, p. 133.
2) H. Kumagai, T. Takahashi, T. Kubo, and M. Ishihara: Ioniz. Radial., 12 (3), 38 (1986).

137
RIKEN Accel. Prog. Rep. 22 (1988)

111-4-6.

Combined Effect of cis-Diamminedichloroplatinumand Heavy Ions on Mammalian Cells In Vitro
M. Suzuki, S. Yamashita, K. Nakano, and 1. Kaneko

Many experiments were carried out on the
combined effect of X-rays and cis-dichlorodiammineplatinum (CDDP) on mammalian cells
in vitro as summarized below. (1) The synergism
which reduced the extrapolation number of asurvival curve was found from the treatment
with CDDP within two hours after X-ray
irradiation. I) (2) CDDP plays a role as a radiosen~sitizer for hypoxic cells. 2 ,3) (3) The recovery fromsublethal damage (SLDR) and from potentiallylethal damage (PLDR) was inhibited by CDDP
treatment. 3•4) These results prompted us to carryout studies of the combination effects of CDDP
and heavy ions in relation to the cancer radiotherapy using heavy ions.
Chinese hamster V79 cells were cultured in
Eagle's·minimum essential midi urn supplemented
with 10% fetal bovine serum in a 5% CO 2 incubator at 3TC. The cells were inoculated onto coverglasses of 22 mm in diameter attached to plastic
dishes of 35 mm in diameter with silicon greaseat a concentration of 1 x 10 4 cells per dish. After
15 h incubation, cells were irradiated to various
doses with heavy ions (95 MeV nitrogen ion or 22
MeV helium ion) from the cyclotron. Before
irradiation, cells were add;~ with CDDP of 5 Jig/
ml and kept for one hour \at 3TC. After CDDP
treatment and irradiation, the cells were trypsinized and seeded onto 60 mm plastic dishes. Cultures were incubated for 7 days in a CO 2 incubator at 37°C to form colonies. The colonies were
fixed, stained, and then counted. We assessed the
combined effect by calculating the surviving
fraction (S. F.) given by
the number of colony counted(treated with radiation & CDDP)
S. F.
the number of colony counted(treated with CDDP)
Figure 1 shows the cytotoxicity of CDDP on
V79 cells treated with various concentrations of
CDDP at 37°C for one hour. The results indicatethat the survival curve has an initial shoulder at
low concentrations of CDDP and at high concentration (:<: 5 ,um/ml) becomes exponential.
Figure 2 (a and b) shows the combined effect of
He ion and CDDP. The synergism was found inboth cases of the CDDP treatment before andafter irradiation. In the case of the CDDP treatment before He-ion irradiation, an extrapolation
number (n value) was 3.5 and the Do value (Dowas determined from the straight portion of thesurvival curve as the dose required to reduce thenumber of surviving cells to 37%) was 0.75 Gy(Fig. 2a). The n value is the same, but the Do
value is 0.68 times smaller than that of untreatedcase (Do = 1.1 Gy). The results indicate thatradiosensitivity becomes high by treating with
CDDP before He-ion irradiation. In the case· ofthe CDDP treatment after He-ion irradiation, then value is 1.0 and the Do value is 0.90 Gy (Fig. 2b).
The initial shoulder of the survival curve vanishes to be the same as that in the untreated case(n = 3.5; Fig. 2b), indicating that SLDR is inhibited by the treatment with CDDP after He-ion
irradiation.
Figure 3 (a and b) shows the combined effect of
N ion and CDDP. The results indicate that thesynergism is found in both cases of the CDDP
treatment before and after irradiation. The Do
CONC.of COOP (~g/ml)
10
20

o
o

,, ~

\

cooP

2\
-1

10

1 hour at 37"C

2

\

\

Fig. 1. Dose response curve of V· 79 cells exposed to
CDDP for 1 h at 37°C. Results are presented as themeans ± S.F. of three independent experiments.

138

M. Suzuki, et al.
DOSE (Gy)DOSE (Gy)

10° 0

2

3

4

5

2

6

3

4

6

0,

6o~~

10-

~"'~:'"

He ion

"

1

~.~~~
5""~

10-2

37'c 1hour10-

1

fr 10-

2

Z

0

f=

"~

u

0\

He ion" COOP

51Jg/TT11
37'C 1hour

l?

z
:>
:>
0:

::J
if)

10-3

10-3

6

\
10-'

10-'

(b)

(a)

Fig. 2. Combined effect of CDDP and He-ion irradiation. (a), treated with
CDDP of 5 ,um/ ml for 1 h at 37°C (6 ) 2 h before irradiation; (b), treated with
CDDP of 5 ,um/ ml for 1 h at 37°C (6 ) 3 h after irradiation; 0 , CDDP
untreated.
DOSE (Gy)DOSE (Gy)o210 ° ~', - . - - - r-

3

o

6
5
234
10° ~-.---r--'----'-""-----'

4.,..----,--.,..-----,~'"•" , \ \ , """ " ,N
" ion

z

o
-I
f= 10

6

Z

0.=1.3 Gy~

0.=1.3 Gy

010

,

f=

~

N ion

"""""

_I

u

«

0:
LL

l?
Z

>

:>

~ 10- 2

CODP"N ion
ml
5fJ9I
37'C 1hour

6

l?

"""

Z

:>
6

"" "

~

-2
::JlO

if)

0.= Q94 Gy

,,
,

,,

0:
LL

N ion .. CDOP
5fJ9/ml
37'C 1hour

,,

,,
,

,

0.=0.90

-3

-3

10

10

(b)

(a)

Fig. 3. Combined effect of CDDP and N -ion irradiation. (a), treated with CDDP
of 5 ,um/ ml for 1 h at 3rC (6 ) 4 h before irradiation; (b), treated with CDDP
of 5 ,um/ ml for Ih at 37°C ( 6 ) 3 h after irradiation; Dashed line, CDDP
untreated.

values of the CDDP treatment before and after
irradiation are 0.94 Gy and 0.90 Gy, respectively.
On the other hand, the Do value is 1.3 Gy in thecase of the CDDP untreatment. Therefore, theradiosensitivity becomes 1.4 times high compared with the case of combination of CDDP and
N ion.
The combination effect of CDDP and heavy
ions was found to be dependent on the type ofradiation synergism which alters the Do value

without the alteration of the n value.
References
1) S. Momiki, Y. Yamaguchi, and T. Miyamoto:]. jpn.
Soc. Cancer Ther., 22, 2352 (1987).
2) I. J. Stratford, C. Williamson, and G. E. Adams: Br.].
Cancer, 41, 517 (1980).
3) P. Carde and F. Lavel: Int. ]. Radiat. Oncol. Biol.
Phys., 7, 929 (1981).
4) A. Dritschilo, A. J. Piro, and A. D. Kelman: Int. ].
Radiat. Oncol. Biol. Phys., 5, 1345 (1979).

139
RIKEN Accel. Prog. Rep. 22 (1988)

111-4-7.

Dependence of the Strand Breakage in DNA on Radiation Quality
1. Kaneko, T. Kosaka, K. Nakano, K.F. Barverstock, and C. McCintyre

Energy transfer along DNA molecules following the deposition of ionizing energy has been
postulated to be a possibly influential mechanism
in radiobiology. The existence of such processes
has not yet been unequivocally demonstrated.
With a view to testing for such processes a dry
DNA/ salt film matrix has been adopted which
optimises those mechanisms which follow ionizing energy that is directly deposited in the DNA.
A technique for assessing the full distribution of
the broken fragments of irradiated DNA has also
been developed using the electron microscope
imaging technique. In experiments carrid out so
far these two techniques together have demonstrated that following irradiation with cobalt 60
y-rays abnormal distributions of fragment
lengths are obtained. There are two main proposals to account for these observations namely,a) that the track structure of the radiation andthe geometric distribution of the DNA moleculesin the target film interact in such a way as togenerated abnormal distribution or b) thatenergy transfer processes within the DNA are
operating and that the sites of damage are notnecessarily the sites of energy deposition. Either
hyposthesis would have considerable implications for the understanding of radio-biologicalmechanisms. 1)
In investigating further the two hypotheses themost favoured variable is radaition quality. For
this reason a series of experiments involving a
range of charged particles of different masses
and velocities is proposed. The most interesting
qualities lie in the range of energies from 0-10
Me V / amu and ions of up to 40 atomic mass units.
Such radiations are best obtained from various
variable energy cyclotrons. Within these limits awide variation in -the spatial distribution of ionizing events can obtained. Track structure models
are available and would enable a detailed interpretation of the results in terms of clearly
defined physical parameters.
A further variable which has been found to beinteresting is the size of the DNA molecule.
Currently available techniques enable us to
manufacture molecules, both linear and circular,
in range of lengths from submicron to the orderof tens of microns. A further variable is thewater content of the DNA film which can becontrolled by manipulating the relative humidityof the enviroment in which the film is contained.
Experiments of this kind are important inradiobiology since the implicit assumption ofmany models used to extrapolate over the variables of dose, dose rate and radiation quality relyon the assumption that damage occurs in cells at
the sites of energy deposition. Such models are ofimportance for radio-biological protection and to
our understanding of the mechanisms of radiation induced cancer.
In these experiments we have used a supercoiled plasmid DNA (pSVL plasmid, Pharmacia
Co.) with salt to ratios of 0.2 : 1, 1 : 1, and 10 : 1
by weight. Isolation of the DNA was carried out,
as described in the NACS Application Manual
published by BRL, to achieve a preparation
containing a high proportion of supercoiled
molecules. Prior to irradiation DNA was ethanol
precipitated and resuspended in the appropriate
strength N aCl solution free from contaminating
enzymes. This solution was dried down undercontrolled humidity to form a dry DNA salt film
matrix.
DN A samples mounted on thin glass coverslips were attached to the bases of plastic petri
dishes designed to fit standard irradiation
holders. These vessels were flushed with air atroom temperature and relative humidity of 75%.
Irradiations using 5.5 MeV / u and 1.75 MeV / ua-particles, 26 Me V / u Argon ions, and 6 0 CO
y-rays were carried out. Dose rates in the rangeof 30 to 80 Gy / min were employed.
Each sample was dissolved overnight in 75J.lI
of 1.0 M NTEB (1 M N aCI in 10 mM tris (pH 7.6)
and 1 mM EDTA). The preparations were analyzed by gel electrophoresis on a 0.8% agarose
gel in the presence of ethidium bromide. Polaroid
photographs were scanned on a densitometer andthe proportions of the different forms of DNA isdetermined by measuring the area under eachpeak with a SEESCAN image analyzer.
Irradiation of samples at the three salt/ DNA
ratios with 5.5 Me V/ u a-particles indicated considerable cross-linking of DNA at the two lower

140

1. Kaneko, et al.

ratios. Neary, et al. 2 ) noted that some crosslinking in their analysis and this is probably due
to the low salt to DNA ratio used. In earlier
experiments with y-rays we have observed nomarked influence on the frequency of strand
breakage of salt concentration and the relative
absence of cross-linking at ratios of 10 : 1 has theadvantage of improving the reliability of theanalysis.
Single strand breaks were measured using
electrophoresis to determine the loss of the supercoiled form of the plasmid and the efficiency of
breakage for the three qualities of radiation are
given in Table 1. These results are not keeping indata of other investigator who showed that single strand breaks increased with increasing
LET.2) To determine single strand breaks Neary,
et al. denatured the DNA in alkali and measured
the distribution of lengths of single strands using
boundary analysis. The loss of supercoiled plasmid as measured by electrophoresis should prove
more reliable although it will not record alkali
labile breaks. Direct comparison with the resultsof Christensen, et al. 3 ) is complicated due to thefact that these irradiations were not of the track

Table 1. Measurement of DNA single strand breaks induced by different radiation sources.
Radiation

LET(keV / ,urn)

ssb/ dalton/ Gy

y-raysa-particles
a-particles
Argon-ionslow

5.5 ±0.5
6.9 ± 0.73677

9.0 ±2.0

600

11.1 ± 2.0

segment type but for total absorption of thebeam.
Our research is on the way along this line. We
should confirm the present results by using otherions of different masses and velocities and byusing the results of DNA double strand breakanalysis in the near future.
References
1) K.F. Baverstock, and R.B. Cundall: Radiat. Phys.
Chern., 32, 553 (1980).

2) G.]. Neary, V.]. Horgan, D.A. Bance, and A. Stretch:Int. ]. Radiat. BioI., 22, 525 (1972).
3) R.c. Christensen, C.A. Tobias, and W.D. Tayler: Int.
]. Radiat. BioI., 22, 457 (1972).

141

RIKEN Accel. Prog. Rep. 22 (1988)

111-4-8.

In Vitro Cell Transformation and Mutation by Heavy Ions
M. Watanabe, K. Suzuki, M. Suzuki, T. Kosaka,
K. Nakano, and 1. Kaneko

Carcinogenesis and mutagenesis are two of themost important biological effects of ionizing
radiation. With the progress in cell culture techniques, studies on the dose-response relationshipand the mechanism(s) of radiation-induced celltransformation and mutation become possible.
Within the last few years, the transformationand the mutation of cells by ionizing radiation
have been studied by many investigators. Most
quantitative data, however, have been obtained
for low-LET radiation, and a limited amount of
information is available for high-LET ions. 1 - 3 ) In
gereral, high-LET radiation has been foundto be more effective in producing celltransformation 1,2) and mutation 1,3) than y or X
rays. Because on the potential applications ofheavy-ion radiation in cancer therapy, there is aneed for information on the carcinogenic andmutagenic effects of heavy ions. We have initiated transformation and mutation experiments toestimate the carcinogenic and mutagenic potential of normal tissue exposed to high-LET heavyions.
In the present study we have two aims incollecting fundamental data for cancer radiotherapy by high-LET radiations. One is to findquantitative dose-response relationships for the
induction of in vitro cell transformation that canbe used in the estimation on the carcinogenic
potential of the normal tissue. The other is toassess the RBE and its LET dependence.
We used diploid golden hamster embryo cells(GHE) from 13- or 14-day-old embryos as previously reported. 3 ,4) The GHE cells were cultured in
Eagle's minimum essential medium supplemented with 10% fetal bovine serum in a 5% CO 2
incubator at 37°C. The cells cultured on 22-mm
cover glasses at a cell concentration of 3 X 105
were irradiated to various doses of heavy ions or
y rays. After exposed to radiation, the cells weretripsinized into single cells and plated into 60mm dishes at a density that gave about 70 survivors. Transformed colonies were identified asmorphologically altered colonies which weredensely stacked and had a criss-cross pattern as
described previously.5,6) Colonies containing

Dose (Gy)01231156789

01

.:;c:

0.5

'>
~

:J
<II

0.2

!!
qj
u

0.1

....o

c 0.05.~uIII~ 0.02

0.01

Fig. 1. Survival curves of GHE cells by 6 0 CO 'Y rays (.),
!37Cs y rays ( 0 ), N ions (3.1 MeV l u, 530 keY /.um) (.),
He ions (4.2 MeV l u, 36 ke Vl .um), He ions with a100-,um Al absorber (1.7 MeV/ u, 77 keV / ,um) ( 0 ), andX rays (182 kVp) (()).

more than 50 cells were counted as survivors andthe frequency of transformants was expressed as
the ratio of their number of morphologicallytransformed colonies to the total number ofcolonies survived.
Figure 1 shows the survival curves of the GHE
cells following exposed to heavy ions, y rays and
X rays. The results indicate that the heavy ions
are more effective than X rays and y rays for cellkilling. For N -ion and He-ion beams, the cell
survivals exponentially decreased as the dose isincreased. On the contrary, the survival curves
for X rays and y rays have a small initial shoulder at the low dose regions up to 1 Gy, but over
1 Gy they have an exponential damping. The
RBE relative to 60CO y rays at the Do value isabout 2.3 for a N-ion beams (530 keY / .urn), 3.0 for
a He-ion beam without absorber (36 keY / .urn),
and 3.0 for a He-ion beam with a 100-.um Al
absorber (77 ke V / .urn). Figure 2 shows that celltransformation of GHE cells after exposure tovarious radiations. The results indicate that theheavy ions are much more effective than y rays
in producing in vitro cell transformation. The
transformation frequency per surviving cells for142

M. Watanabe, et at.
500
III
~

o

.:;>
~

~ 100
<D

o
~

50

aI

a.
>u

~

aI

C

a.
u. 2

aI

:s

0-

I-

aI

.!:;

10

o
Dose (Gy)Fig. 2. Dose-response curves for cell transformation of
GHE cells by GOCo y rays (.), l37Cs y rays ( 0 ), N ions(3.1 MeV l u, 530 keY I ).tm) (.), He ions (4.2 MeV l u, 36
ke V I,um) (.), He ions with a 100-).tm Al absorber (1.7
MeV l u, 77 keY I ).tm) ( D), and X rays (182 kVp) (()).

N -ion and He-ion beams, and y rays appears to
be steeply linear up to 1 Gy and over 1 Gy showsa constant level or a slight increase. The frequency for a constant level is about 2.5 times
higher for aN-ion beam and about 2 times higer
for a He-ion beam than y rays. When the RBE isdetermined as the transformation frequency
per surviving cell at the same frequency levelup to 1 Gy, the RBE relative to 60CO y rays is
about 3.3 for N ions, 2.4 for He ions without anabsorber, and 3.3 for He ions with a 100-,um Al
absorber.
6-Thioguanine (6TG) was used to study themutation induction in GHE cells by various radiations. A part of irradiated GHE cells wereseeded at a low density and incubated for 8 days
before selecting for mutants with 6-TG medium
as previously reported.7) The results are given in
Fig. 3. X rays increased the number of mutants
per 10 6 viable cells curvilinearly with an increasein dose. Heavy ions appear to be highly effective
in producing mutation at lower doses up to 1 Gy,
as compared with y rays. The frequency of 6TG
mutants, however, decreased drastically athigher dose than 1 Gy. The RBE value, which
was determined by taking the mutation frequency per viable cell induced by an X-ray dose
given 37% survival as a reference point, wasabout 3.9 for He ions (4.2 MeV l u, 36 keY l ,um), 3.
8 for He ions with a 100-,um Al filter (1.7 Me V I
u, 77 ke V l ,um), and 4.9 for N ions (3.1 MeV l u,
530 ke V l ,um), respectively. A comparison of the
RBE's for mutation induction and for cell killingat a 37% survival level indicates that, compares
to X rays, heavy ions can produce more mutation

o

"

5

Dose (Gy)Fig. 3. Dose-response curves for mutation at HGPRT
locus of GHE cells by N ions (3.1 MeV l u, 530 keY I ).tm)(.), He ions (4.2 MeV / u, 36 keV / ).tm) (.), He ions witha 100-).tm Al absorber (1.7 MeV l u, 77 keY I ).tm) ( D), andX rays (182 kVp) (()).

lesions than lethal injures.
Because heavy ions has been known to damage
DNA, we examined the chromosome aberrations
immediately after irradiation. The efficiency of
induction of every type of aberration, including
chromatid gaps, breaks, and translocations, wasless in cell exposed to heavy ions than those to X
ray and y rays. Some investigators reported thatthe number of the initially induced DNA strand
breaks resulting from exposure to high LET
radiations was smaller than those from X rays
and y rays.B,9) Our data of chromosome analysis
are comparable to there results. Low LET radiations required more than four times chromosomal aberrations for the induction of the same
biological effects.
The results indicate that the heavy ions are
more effective for the induction of transformation and mutation than X rays and y rays. The
studies on the mutation and cell transformation
with heavy ions give us a great insight into themolecular mechanisms of cell transformation.
We plan to continue the studies on chromosomal
and DNA lesions induced by heavy ions and hopethat these studies provide information on thenature of molecular structure alterations in DNA
which are related to oncogenesis and mutagenesis.
References
T.e. Yang, L.M. Craise, M. Mei, and C.A. Tobias:
Radiat. Res., 104, S177 (1985) .
2) e. Borek, E.J. Hall, and H.H. Rossi: Cancer Res., 38,
1)

M. Watanabe, et al.
2997 (1978).
3) R. Cox, J. Thacker, D.J. Goodhead, and R.J. Munson:
Nature, 267, 425 (1977).
4) T.C.H. Yang, F.Q.H. Ngo, J. Howard, and C.A.
Tobias: Biological and Medical Research with Accelerated Heavy Ions at the BABALAC, Lawrence
Berkeley Lab., Univ. Calif., p. 149 (1980).
5) M. Watanabe, M. Horikawa, and O. Nikaido: Radiat.
Res., 98, 274 (1984).

1436) M. Watanabe, N. Suzuki, S. Sawada, and O. Nikaido:
Carcinogenesis, 5, 1293 (1984).
7) M. Watanabe, V.M. Maher, and J.J. Mccormick:Mutat. Res., 146, 285 (1985).
8) K. Sakai, S. Suzuki, N. Nakamura, and S. Okada:
Radiat. Res., 110, 311 (1987).
9) K. Eguchi, T . Inada, M. Yaguchi, S. Sato, and I.
Kaneko: Int. ]. Radiat. BioI., 52, 115 (1987).

144
RIKEN Accel. Prog. Rep. 22 (1988)

111-5.

I nstru me ntati on
1.

Network In the RIKEN Accelerator Facility
T. Ichihara, T. Wada, and T. Inamura

In the year of 1988, the environment of the
networks around the RIKEN Accelerator Facility has been improved; here we describe its outlines.
(1) Local area network
An ethernet cable is stretched all over RIKEN
Ring Cyclotron building to connect V AX computers and terminal servers. Currently 6 DEC net
nodes, 5 terminal servers, and 3 TCP / IP nodes
are connected to the Ethernet in RIKEN Ring
Cyclotron buildings.
In the Spring of 1988, ethernet cables werestretched over the main research building andthe linac building. Figure 1 shows the current
ethernet cable routing in RIKEN. One segment of
Ethernet consists of a 500 m coaxial cable. Segments of Ethernet are connected with, each otherby "data link bridge" or "buffered repeater."
While data link bridge repeats only the ethernet
packets which cross over the segments, bufferedrepeater repeats all the ethernet packet. Opticalfiber cables are used to connect the ethernet ofthe acceleratOr facility and main research buildMain Research building

A~:_e_I~!~~~~ __ ~~:_I~I!yRing Cyclotron --',----2F. . . _ _ - - - - - - SF"[--®-(
i,

BOOm SF.JR'-(-------- 4F
---"y

.

SPQm

3F

r-:::====--- 2F

"

1F

:

B2F

SOOm

t--- ----------------21=---- i
,

,

1F

'-f----...i/.II.W""- 1F

Liniac lab.
;Optical cable___ _T..cJy!r: ____ ______ _:'"-___ !:~~~~t_ J!"~~~':~ __",'® Buffered Repeter

SOOm

B
SOOm

_______ T9?!1f'. _____ _____ _____ Frontier Lab. Building(repeat all the packets)[i] Data link Bridge(repeat only crossing packets)@ Optical tranceiver~ Network Management consoleFig. 1. Ethernet cable routing at RIKEN.

ing.
In the accelerator facility, DECnet is the main
protocol of Ethernet. Local Area Transport(LA T) protocol is also used for terminal servers.
In a VAX-8350 computer, CMU/ TEK TCP/ IP
software is installed on the V AX/ VMS operating system to communicate to TCP / IP nodes in
the main research building.
(2) Terminal connection to the host computers via digital PBXIn the spring of 1988, the PBX of RIKEN was
replaced by new one. The new PBX (FETEX3700) supports not only analog communicationlines, but also digital data transfer lines. Many
host computers in RIKEN are connected to thedigital PBX by digital Access Units (DAU) or by
Digital Network Interfaces (DNI). Figure 2
shows the digital PBX and host computer connections. In the accelerator facility 12 DAU's are connected to a FACOM M380 computer, 11 DAU's
are connected to V AX computers, and 1 DA U isconnected to M60 computers for accelerator
control.
In order t<? access host computers connected to
the PBX, digital telephones with RS232C ports
are placed in each room. Usually a personal
computer (Macintosh, PC9801 etc.) is connectedto the RS-232C Port of a digital telephone at 9,600 bps and can be used as a terminal of the hostcomputer. Host computers can be selected by"ATD x x x x" command. There is also ananalog modem pool to access these digital linesof the PBX from the "public telephone line +modem" from outside of the RIKEN.
One of the most convenient features of this
digital telephone is that a digital port (RS-232C)
and an analog port (voice) can be used independently at the same time. When someone is usinga RS232C port of the digital telephone to connect
to the host computer, he can also call a person by
the same telephone with voice.
(3) Wide area network(a) BEPNET In the end of 1988, the DECnet
link of the RIKEN accelerator facility was con-

145

T. Ichihara, et at.
Riken PBX LAN
600
t - - - - - - - - A N A L O G Telephone~ ______~30~__~(Push Phone)

DigitalPBX

t--_ _-IPaging SYllem(Dial-In)

FETEX-3700

Voice Mail

Modem Pool

Fax Mailbps

2400 '2
1200 '3300 '1

Ether net
TCP/IP

X.25 (VENUS-P) OTE Address of Micro VAX II
4401 - 4384118

Any computer connected to the digital PBX (FETEX 3700)
can be accessed from the Digital telphone with RS232C port.

OAU Telephone number list
7711 9600 bps 3ch
7712 9600 bps 3ch
7713 4800 bps 2ch
7721 9600 bps 5ch
7731 Auto
4ch(Telne!, FTP, MAIL)

FACOM M-380 MSP
FACOM M-380 MSP
FACOM M-380 MSP
VAX-8350 VMS
VAX Terminal servers

Telephone (voice) and digital data link by RS232C port canbe used at the same time.

(8-bit, no-parity, Full-duplex, xon-xoff flow cont.)

Fig. 2. Digital PBX of RIKEN.

nected to the world-wide High Energy Physics
Network (HEPNET) via National Laboratory ofHigh Energy Physics (KEK) at Tsukuba. For thislink, NTT DDX-P (X. 25) is used till March 1989.
From April 1989, it is replaced by a leased digitalline of NTT at 9,600 bps. At the same time, a
DEC net link to the University of Tokyo will also
start the operation using a leased digital line of
NTT at 9,600 bps.
A Micro VAX 3600 computer at RIKEN in
Komagome and a VAX11 / 730 computer ofTokyo Institute of Technology are connected to
the RIKEN accelerator facility with DEC net at 9,600 bps using a 3.4 kHz-band leased analog lineof NTT and modems.
The DECnet node names and address are as
follows:(40.950) Micro VAX II
RIKEN::(40.951) VAX 8350
RIK835::(40.952) DECnet/ SNA
RIKSNA::
Gateway(40.953) Micro V AX II forRIKMVl::experiment(40.954) Micro V AX II forRIKMV2::experiment(40.955) V AX Station II/RIKVS1::GPX(40.956) Micro V AX 3600
RIKSOR::

146

T. Ichihara, et al.

at komagome Area
V AXl1 / 730 at
Tokyo Inst. of Tech.
(40.958) Micro V AX II forRIKMV3::experiment (linac)(b) Junet Some VAX's in the Accelerator
Facility is connected to a domestic computer
network between reseach facilities, J unet, via
F ACOM A50 Gateway computers. Figure 3
shows the network between different computers
at RIKEN Accelerator Facilities and also J unetconnection. The node name of J unet and TCP l IP
address are as follows:
RIKMV. RIKEN. JUNET(192.48.138.151) RIKEN::
RIK835. RIKEN. JUNET(192.48.138.152) RIK835::
RIKTIT::

,

....

...

"8"

''

(In the end of this year!!)Fig. 3. Network between different computers at RIKEN
Accelerator Facility.

(40.957)

147
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-2.

Large Scattering Chamber at RIKEN Ring Cyclotron Facility
T. Nakagawa, I. Tanihata, and S.M. Lee

For the study of reaction mechanisms inintermediate-energy heavy-ion collisions (20 <E < 100 MeV/A), a large scattering chamber will
be installed in the target room E2. A schematic
drawing of the scattering chamber is shown in
Fig. 1. Its diameter and length are 2.95 m and 4.
8 m, respectively. To satisfy various needs inexperiments, three different target positions (PI,P2, and P3) are provided, and three movabledetector arms are controlled independently ateach target position. In order to extend the flightpath near the scattering angle of 90 degrees, a

Beam

Cryogenic Pump

PI
P2

Table
/ .
I

Movable Arms :!

P3

small chamber may be attached at the side of thelarge scattering chamber (see Fig. 1). The maximum flight paths are 3 m at forward angles and2.5 m at 90 degrees.
The vacuum system consists of a rotary pump(l5,0001/min), a mechanical booster pump (100,OOOI/min) and two cryogenic pumps (16,0001/s).
A vacuum of 5 X 10- 6 torr is achieved within 1 hfrom 1 atm with this system. For routine operation, P = 1 X 10- 6 torr is expected.
A design of detector systems is in progress tofacilitate measurements of reaction products inthe large scattering chamber:
1) A large Frish-grid type ionization chamber;
2) A large two dimensional position sensitive
Parallel Plate Avalanche Counter (PP AC);
3) A PP AC and a Channel Plate Detector(CPD); and
4) A large size solid state detector.
The large Frish-grid type ionization chamber
will be used as a L1 E-E counter telescope forcharge identification. The PP AC and the CPD
will be used as a time pick off detector for a
Time of Flight telescope. A 47l' counter formeasurement of light particles and y rays canalso be placed in the large scattering chamber.
The great advantage of the large scatteringchamber is its capability of a long flight path.
This capability provides a possibility for studying reaction mechanisms of heavy ions in theenergy region supplied by RIKEN Ring Cyclotron.
1m

Small Chamber

Cryogenic Pump

Small Flange

\

~

\

I

I
/

Small Chamber

Cryogenic Pump///

Fig. 1. Schematic drawing of large scattering chamber.

~

148
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-3.

R1KEN Swinger-Spectrometer System

H. Ohnuma, K. Hatanaka, S. Hayakawa, T. Ichihara,
M. Ishihara, S. Kato, T. Kubo, S. Kubono, K. Maeda,
T. Nakamura, H. Orihara, H. Shimizu, H. Toyokawa,Y. Yano, M. Yasue, H. Yoshida, and S. Wakasa
RIKEN swinger-spectrometer system1) is at its
final stage of designing. The system has beenordered from The Japan Steel Works, Ltd., andthe construction has started. Major components
will be delivered in summer 1989. Field measurements will start shortly afterwards, and final
installation and adjustment will be completed by
the end of 1989.
There have been several changes in the designfrom the Progress Report last year, although thebasic concepts remain unchanged. Parameters ofmagnets are summarized in Tables 1 and 2. The
twister is now a quadrupole septet instead of aquadrupole triplet. This ensures an exact rota-

Fig. 1. Cross section and the field distribution of the first quadrupole magnet of thespectrometer.

Table 1. Parameters of swinger magnets.
WDI
Central orbit
radius (m)Deflection angle(deg)Maximum field(Tor T / m)Pole gap or bore
radius (cm)Weight (t)Maximum power
consumption (k W)

Table 2.

WQ1/WQ2

WD2
2.3

2.3

150

60
1.51

15

1.51

6

3.5

6

4.5

0.18

11

94

2.9

168

Parameters of spectrometer magnets.
PQl

Central orbit
radius (m)Deflection angle(deg)Maximum field
7.7(TorT/ m)Pole gap or bore
13.5
radius (cm)Weight (t)15.8
Maximum power
consumption (k W) 76

PQ2

PDl

PQ3

2.4

PD2
2.4

60

120

tion of the shape of the object and the beam
divergence at the object. 2 ) The quadrupole tripletof the swinger has been replaced by a quadrupole
doublet to save space and reduce the weight ofthe swinger. The distance between the twodipoles of the spectrometer has been extended
due to the space problem.
Each magnet has also been modified after
repeated field calculations. Shapes of the yokes,
shims, coil windings, field champs, etc. of thedipole magnets have been carefully adjusted to
optimize the field distribution at various excitations. The first quadrupole magnet of thespectrometer, which is of a split type in order torealize large acceptance and small angle measurements as reported previously,1) has a crosssection shown in Fig. l.
The mechanical design of the support structureof the swinger magnet is in progress. Vacuum
chambers, detector boxes and a scattering chamber are also being designed.

4.0

1.5

3.3

1.5

18.5

20

13.75

10

References

8.5 102

1.9

82

30

199

1) H. Ohnuma, et at.: RIKEN Accel. Prog. Rep. , 21, 164(1987) .
2) S. Kato: Nucl. Instrum. Methods A, 254, 487 (1987).

79

204

149
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-4.

Facilities for Atomic Physics at RIKEN Ring Cyclotron
Y. Awaya, Y. Kanai, T. Kambara, and T. Chiba

We have constructed a beam line with equipments which are mainly dedicated to the study ofatomic collisions in the E2-experimental room at
RIKEN Ring Cyclotron. The beam line wasdesigned so that we can get a vacuum better than
10- 8 Torr, if necessary, that is, CF seals or metal
Q-rings are used when required. In order toreduced the background radiation as low as
possible, there are no slits or baffles in the experimental room. A charge stripper setup is installed in the cyclotron vault to provide different
charge-state projectile ions. The equipments
which are installed on the beam line are as follows (also shown in Fig. 1).

FROM RRC~

E2 EXPERIMENTAL ROOM~SWITCHING r7i.~I~
MAGNET m~,~\'

QUADRUPOLEMAGNET 1 ~

.

..,f

~

~

~

TARGET CHAMBERFOR UNIVERSAL USE ~

.

~

~

QUADRUPOLE~MAGNET 2 ~

~

~

~

"1

TA;g~Tx:~~ERi
~-

~

;;;

[I

~

..0

J
\
. 1':' CHARGE ANALYZING ~i",: . ... ..

MAGNETI.l\-.i PPAC
BAEM ~ 0\ BAEMDUMP ~
DUMP
Fig. 1. Experimental setup for atomic physics in theE2-experimental room. The position of the target
chamber for measurement of angular distribution of X
rays and the quadrupole magnet 2 will be changed in
the near future.

Target chamber for universal use
The size of the chamber is 100 cm in diameter X 50 cm in depth. Inside the chamber, thewall is covered with a J1.-metal shield. There area turn table, two arms and a target holder in thechamber and they are controlled from the counting room.
(1)

Target chamber for measurement of angular distribution of X rays
The size of the chamber is 30 cm in diameter.
The window is opened from 25° to 155° withrespect to the beam for the measurement of X
rays and is covered with a sheet of 25 J1.m Mylarfilm. There are a target holder inside the chamber and two turn arms outside which rotate
around the target holder carrying a Si (Li) or Ge
detector with a liquid nitrogen Dewar vessel.
The target holder and two arms are controlledfrom the control room.
(2)(3) Charge state analyzer (broad range)
The specification of the charge analyzing
magnet is as follows:
radius250 cmmaximum filed
15,000 Gauss
35 degree
deflection angle
gap of the pole pieces
71 mm
The magnet can be rotated from 0° to 60° respect
to the beam direction. A position sensitive parallel plate avalanche counter or a solid state detector is used for the detection of the ions.
Another facility for atomic physics has been
constructed in the ion source vault of the AVF
cyclotron. When the A VF cyclotron is not working, ions from the ECR ion source l ) are available
for the study of the atomic physics. 2 )References
1) K. Hatanaka and H. N onaka: RIKEN Aeeel. Prog.
Rep., 21, 212 (1987).
2) H. Sakaue, et at.: This Report, p. 74.

150
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-5.

Falling-Ball Irradiation System and the Hot Laboratory

M. Yanokura, Y. Ohkubo, S. Ambe, M. Iwamoto, and F. Ambe

The falling-ball irradiation system and the hotlaboratory notified in the preceding volume ofthis report 1 ) were constructed and tested withsuccess. This report describes some details ofboth facilities.
The schematic view of the whole arrangementof the irradiation system is shown in Fig. 1. The
irradiation chamber is installed near the end of

A

o .

.

0

.

... .
•

40

e'

0

••

'

•

•

•

the oblique beam line in the E3 irradiation room.
The transport tube for the 'falling ball' passes
through the floor of the room down into a hoodin the hot laboratory downstairs. The chamber
and the transport tube can be evacuated to 1 x
10- 5 and 1 x 10- 1 Pa, respectively.
Target foil is mounted in a 'falling ball' as
shown in Fig. 2. The ball with a diameter of 42
mm is made of aluminum and has a piercing
cylindrical hole for a beam and also a groove for
guide. The diameter of the hole for the beam canbe as large as 22 mm.
Several balls can be set at the same time in thestand-by holder tube connected to the chamber.
A quartz plate for beam monitoring is mounted
on the first 'falling ball. ' After evacuation of thechamber, the balls can be transferred one by one
to the irradiation position of the chamber, thedirection of the target against the beam being
kept proper by the groove on the ball and rails in
the chamber.
After irradiation, the ball is transported down
to a radiation monitoring station under the

r

lAD J
I

Fig. 1. The whole layout of the 'falling ball' irradiation
system. A: irradiation chamber, B: stand-by holder tube
for the balls, C: vacuum system for the chamber, D:
vacuum system for the transport tube, E: radiation
monitor (ionization chamber), F: hood, G: end station
for the ball, H: control system.

· I~~

[[ill
F

~"l
1.,. • •

'w

U

B~ ~B

1

liJl [c

r--

0

QE

f---

D

I

C

Fig. 2. The 'falling ball.' A, B: The separable two partsof the ball, C: screw groove, D: target foil, E: suppression ring. F: groove for guide.

Fig. 3. The layout of the hot laboratory. A: hood for theend station of the 'falling ball,' B: hood for chemical
work, C: hot sink, D: work bench, E: tank for liquid
waste, F: duct for exhaust.

M. Yanokura, et al.

chamber. If the radiation level is confirmed to beappropriate for handling in the hot laboratory,
the ball is further rolled down through the tube
to the hot laboratory. After passing through a
deceleration device, the ball stops at the end
station in a hood. The gate valve near the end of
the transport tube is then closed, the terminal lidof the tube is open, and the ball with the irradiated target is taken out. Thus, the target can beready for physical and chemical studies within
one minute after the end of irradiation. Whole
the procedure can be controlled from the control
station installed in the hot laboratory. If a vessel
with a vacuum-tight valve is attached at the endof the transport tube, an irradiated target can besealed in the vessel directly and can be transport-

151

ed to other controlled areas safely.
In Fig. 3 is given the layout of the hot laboratory. There are three hoods, one for the end
station of the 'falling boll' and the other two forchemical studies. The laboratory is also
equipped with workbenches, hot sinks, and so on.
It is, however, considered to be used only forexperiments using rela ti vely short -Ii ved 'radioisotopes. Long-lived isotopes are to be handled in
the radioisotope experiment facility in the cyclotron building.
Reference
1) M. Yanokura, Y. Ohkubo, S. Ambe, and F . Ambe:
RIKEN Accel. Prog. Rep. , 21, 163 (1987).

152
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-6.

Target Transportation System for a One-Meter
Diameter Scattering Chamber
Y. Ikegami, K. Nishi, Y. Watanabe, K. Endo,
K. Kubo, M. Iwamoto, and F. Ambe

A target transportation system was designed
and constructed for the Mossbauer spectroscopyof 57Fe using a short-lived source nuclide, 57Mn
(1.45 m). It is installed in a one-meter diameterscattering chamber at the #1 course of the cyclotron.

The plane view of the system is shown in Fig.
1. The target (A) is irradiated at the center of thechamber with a cyclotron beam. After irradiation the target is transported to a side window of
the chamber for Mossbauer measurement bymeans of a motor (B) and a drive wire (C). The

J

K

Fig. 1. Plane view of the target transportation system. A, Target; B, motor; C, drive wire; D, target holder; E, target
rotator; F, spring; G, pole; H, moving rack; I, limit switch; J, main rail; and K, subrail.

time required for the transportation is about 10 s.
When the measurement is finished, the target is
moved back to the center of the chamber for
further irradiation. The cycle of irradiation andmeasurement can be repeated infinitely, the timeof both steps being selectable to be from 1 to 999
s from the control room of the cyclotron.
The target is mounted on a holder (D) slanted
at an angle of 45 against the beam. The holder is
set on a rotator (E) with a long bent tail. It canrotate around its central axis, but is strained in
the clock-wise direction with a spring (F). So
long as the target is in the center of the chamber,that is, in the position for irradiation, the target
faces the direction of the beam, the rotation of
the rotator being hindered by a pole (G). When0

the rotator moves toward the window with its
rack (H), the tail of the rotator is released fromthe pole and the target turns to face the window.
In Fig. 1 are shown the target assembly in both
irradiation and measurement positions.
The system has been successfully utilized for
57Fe Mossbauer spectroscopy with a 57Mn
source. 1) It is also expected to be useful for y-ray
spectroscopy of nuclides with a half-life exceeding several seconds, since the y-ray backgroundis considerably reduced in comparison with theusual on-line experiments.
Reference
1) Y. Watanabe, et at.: This Report, p. 121.

153
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-7.

Test of a Superconducting Secondary Beam Transport Systemwith Large Solid Angle (SLO)
K. Ishida, T. Matsuzaki, K. N agamine, H. Kitazawa,
Y. Miyake, and E. Torikai

A new type of beam transport system for lightcharged particles (Superconducting Large (2beam course; SL(2) was constructed at E7B
course of RIKEN Ring Cyclotron (RRC). It
makes use of the focusing property of anaxially-symmetric magnetic field. This type offocusing system is featured by its ability toaccept the charged particles emitted in a largesolid angle with good momentum selection. The
main purpose of this beam channel is to collectsecondary particles as many as possible. The
principle and the design of the system havealready been reported. I) The apparatus consistsof three superconducting coils, where the currentof each coil (11, 12, and 13, respectively, from thetarget) can be adjusted independently. The coil isof an air-core design without an iron return yoke.
This type of coil was chosen because the field isprecisely calculable and proportional to the current. This means that an envelope of the beam
trajectory can always be fixed irrespectively tothe momentum by only scaling the current.
Otherwise, the slit system would become very
complicated. But this coil caused a nonnegligible
fringing field to the primary beam, and correc-

tion had to be done as shown later.
Here, we report a test experiment performedby using a completed SLn system. Before an
in-beam experiment, the system was tested byusing a 106Ru f3 source, which was set at thetarget position, and the currents 12 and 13 weretuned for each value of 11 to obtain the maximum
number of f3 rays at a counter placed at thefocusing point. The results are shown in Fig. 1.
The determined values of 12 and 13 agree very
well with those calculated by a ray tracing program. But the measured collection efficiency wasestimated to 'be smaller than the designed value
by a factor of 4. The difference may come from,for example, mis-alignment of slits, misalignment of source position, blocking by ascrew slit and slit supports, etc. Precise estimation of the beam loss is now in progress to makenecessary modifica ti ons.
The system was tested by using a 14 N beam of
42 Me V lu from RRC. First, the deflection of a
primary beam by the fringing field was correctedby two deflecting magnets placed before andafter the production target. For each excitationof the coils, the deflection magnets were adjusted

LO test with 106Ru Source

1500
1250
1000
750
500
250
0 8

LO test with 14N Beam
GRAPHITE TARGET[::::::2S5 :~

1500
1250
1000
750
500
250
0 4.5

9

10
2 (A)

12

11

COIL

2000
1500
., 1000
500
0
u
0 0

'6:::'1"::1"'1
t~ ,1, -

~
8

,
0

i

5

10

15

20

I",
30
25

COPPER TARGET

lu:

5.5
3 (A)

6

6.5

COIL

Fig. 1. Number of collected f3 rays from l06Ru
source as a function of 12 (above) and 13 (below). 11
was fixed to 10 A so that the particles with 2 MeV I
c momentum go through. The dotted line corresponds to the case when the 12 is a little off tune.
The arrows shows the design value.

:~ f' ,,1:._m:.I_.:.'u'.:.' ::' 1' :: ' ~t"'I~,,_t'_"_:'_'I""''''_
I "

o

o

5

10

15

20

25

,

30

MOMENTUll (MeV/c)

Fig. 2. Positron momentum distribution measured
by SLO, when a beam of 1 4 N with 42 MeV lu hits agraphite target (above) or a copper target (below).
The dotted lines correspond to the case when thetarget is out.

154

K. Ishida, et at.

so that the primary beam hits the center of atarget and goes into a beam dump.
Next, the coil currents were tuned to collectthe positrons produced in a target. The tuning
was carried out for various momenta of
positrons. The positrons were detected with apair of plastic scintillation counters. The numberof positrons detected is shown in Fig. 2 as afunction of the positron momentum for a graphite target and for a copper target. The number of
positrons has a peak around 7.5 MeV Ic for thegraphite target. The number is much smaller forthe copper target. This may indicate that thesource of positrons are mainly due to radioactive
nuclei produced in the reaction.
Finally, we tuned the system to 27 MeV I c inorder to get surface muons from the copper
target. The surface muons are expected to be
produced when the pions produced in heavy-ion
reactions stop and decay in the skin of the target
material. The muon was identified by using a
stack of three scintillation counters. The muoncomes through the first thin counter and stops inthe second counter. The muon then decays with alifetime of 2.2 J1.S and emits a positron. The
positron hits the counter 3 with a 50% probability. Thus coincident signals frqm counters 1 and
2 followed by those from counters 2 and 3 with afew microsecond delay is a typical muon signal.
The data obtained in a three-hour run show
about 20 events above a random coincidence
level as in Fig. 3. This number is not muchdifferent from our estimation; 30 muons were

Coincidence Events

30

20

10

o

~~~~~~-L~L-~-L~~~~~

-5

o

5

10

15

TIME (microsec)

Fig. 3. Time difference between 2·3 signal and 1· 2
signal, when a beam of 14N with 42 MeV l u hits acopper target. The dotted line corresponds to therandom coincidence level determined from eachcounting rate. The number around time zero is 19,
700 and is mainly due to penetrating particles.
Time resolution was below 0.1 JJS and far less than
the time bin represented.

expected from the cross section of 400 nb for pion
production and collection efficiencies estimatedby Monte-Carlo calculation. We can expect moremuons when the energy of the beam becomes
higher with the operation of the AVF injector
cyclotron.
Reference
1) K. Ishida, T. Matsuzaki, and K. Nagamine: RIKEN

Aeeel. Prog. Rep., 21, 172 (1987).

155
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-8.

Construction of a New Type of Low Energy Radioisotope
Beam Channel "SLOW" for Surface Studies
T. Matsuzaki, K. Ishida, and K. N agamine
aid of the SLOW beam line, we can investigate
emission mechanisms of various atoms from thetarget surface.
In Fig. 1, the layout of the SLOW beam line isshown. The details about the beam line design isdescribed in Ref. l. All beam line components areelectrostatic lenses with no magnetic field. In thismanner, the ions with an equal charge state anda different mass can be transported and focussed
under the same beam line conditions. The SLOW
beam line is composed of a SOA lens,2) five setsof electrostatic quadrupole lens, a troidal-shaped
electrostatic bend, an X- Y electrostatic deflector
and three sets of slit. At the end of the beam line,
there is located a multichannel plate in order todetect the transported particles. The mass identification of the particles will be performed by

We have constructed a low energy radioisotope beam line "SLOW" in the E7 experimental area of RIKEN Ring Cyclotron (RRC). The
SLOW beam line will be utilized for the study ofemission mechanisms of various low energetic
radioactive atoms from characterized surfaces
and also for the extraction of useful radioisotope
ions for surface-physics studies.
Heavy-ion beams from RRC are injected into
various targets and produce many kinds of radioisotope atoms by nuclear rea-ctions. The
produced atoms are moderated in targets andreach to the target surfaces by thermal diffusion.
At the target surface, a part of the atoms could
evaporate into vacuum and could be ionizedthrough various mechanisms based on the surface physics. By observing emitted ions with an

Sx

ED

TMP

F

1

o
o
w

sx
BOO

1100

o

o
w

F2

BOO

1900

2700

Fig. 1. Layout of the "SLOW" beams channel. The targets are placed at the center of a large high vacuum chamber. The
heavy-ion beams are injected into the target by 70 degree. The beam line components are SOA lens (SOA), electrostatic
quadrupole lens (EQ), electrostatic bend (EB), electrostatic deflector (ED), slit (SXY, SX), and turbo molecular pump(TMP). Fl and F2 are first and second focussing points, respectively.

156

T . Matsuzaki, et al.

measuring the time of flight through the beamline path, where the second electrode voltage of
SOA lens is rectangularly pulsed to define a time
zero of the flight time.
The high voltages are supplied to 32 electrodesof the beam line components through five voltage
dividers. The voltage divider has a main regulated voltage supply (10 kV, 10 mA, stability; 10- 4 /h) and eight independent outputs. The high voltage upto ±5 kV was easily applied to the terminals of electrostatic quadropole lenses. For othercomponents, the voltage of up to ± 10 k V issustainable. The applied voltage can be remotely
controlled from the data taking room of RRC.
A DC regulated power supply (500 A, 16 V,
stability; 10- 4 / h) was installed to heat up thetarget metal. Also, we installed an AC power
supply (20 A, 100 V) for an electron filament inorder to investigate an optical property of
SLOW beam line by using emitted thermal electrons. For the pulsed voltage applying to thesecond electrode of SOA lens, a pulse generator
was equipped, which produces pulses with arising time of < 20 ns, widths from 100 ns to 100
J-tS, amplitudes from 0 to 400 V, and repetition
rates from 0 to 1 kHz. The above three modules
were installed into one shielding box and were
electrically floating to change independently
their ground potential up to ±10 kV. The magnetic shield to the SLOW beam line is now being
designed, which is essential to transport thermal
electrons. The E7 experimental area is locatedjust beside the RRC accelerator and just below
the A VF injector, and the stray magnetic field
was measured to be high.
The vacuum space of beam line was evacuatedby two sets of turbo moleculer pump (300 li s).
At a head of the SLOW beam line, there is alarge high vacuum chamber evacuated with acryopump (1,500 li s), the inside vacuum of which
is aimed to reach as high as 10- 10 torr after
outgasing by baking.
A preliminary evacuation test without baking
proved that the attainable vacuum of the chamber was 1.2 x 10- 8 torr after evacuation for twodays. The setup of a baking heater is now being
preparing, including a temperature control system.
Above the large chamber, we put an additional
chamber equipped with an argon-ion gun, a
LEED/ AUGER spectrometer, and an electric
quadrupole mass spectrometer. The argon-ion

gun (5 k V, 30 InA) is to make ion etching on themetal surface. By employing the LEED/ AUGER
spectrometer (120 deg type), the LEED patterns
for metal surfaces give us crystallographic information and an Auger electron spectrum is used
to analyze the components existing on metal
surfaces. An electric quadrupole mass spectrometer is utilized to analyze the residual gas component of the vacuum; this analysis is essential tocontrol the metal surface.
A primary beam transpotation test to E7 was
performed. A beam spot of 2 mm in diameter was
obtained at the target position of the SLOW
beam line, and no induced discharge phenomena
by primary beams was observed at every electrode of the SLOW beam line component.
In the experiments using the SLOW beam line
to investigate an emission mechanism of ionsfrom the characterized metal surface, a varietyof emitted ions and their yields will be observedby changing experimental conditions, i. e., target
materials, surface temperature, surface treatment, coating materials, crystallographic axis,
target thickness, incoming heavy ions beams andenergy. The superior point of this method is thatvarious atoms generate inside the target and are
emitted from the surface after thermal diffusion;
this method is quite different from the cases of anion scattering or an ion implantation method.
In addition to metal targets, we will try ionic
crystals and rare-gas solids, having large bandgap energies. In the positron studies, it wasobserved that energetic positrons implanted into
various ionic crystal surfaces were re-emittedwith maximum kinetic energies (about 14.7 eV
for LiF) near the band-gap energy.3) This new
surface mechansm is considered to occur also forvarious atoms. We will begin to prepare a raregas solid target.
As described in Ref.1, 6He and 8He beams will
be a powerful probe to many fields. The initialdesign of an ionization device, yield estimation,and optical calculation for a microbeam line are
now in progress.
References
1) T. Matsuzaki, K. Ishida, and K. Nagamine: RIKEN
Aeeel. Prog. Rep. , 21, 170 (1987) .
2) K.F. Canter, P.G. Coleman, T .e. Griffith, and G.R.
Heyland: ]. Phys. B, 5, L167 (1972 ) .
3) A.P. Mills, Jr. and W.S. Crane: Phys. Rev. L ett., 53,
2165 (1984 ).

157
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-9.

Performance of the Stop Detector for Time-af-Flight(T .O.F) System

T. Mizota, T. Nakagawa, K. Yuasa-Nakagawa, H. Fujiwara,
M. Ogihara, Y.H. Pu, and S.M. Lee
In heavy-ion reactions it is often necessary to
use a time of flight telescope to determine themass and energy of the reaction products. Several authors reported the good time resolution(150 ps) achieved for heavy ions for the channel
r:>late detector (CPD)1-4) they used. In order toobtain a better mass resolution with a large solid
angle, we have developed a CPD which provides
a good time resolution and a large effective area,
simultaneously.
A schematic drawing of the detector is shownin Fig. 1. Incident ions pass through a thin foil
which consists of Au (20,ug/ cm 2 ) evaporated on
formvar foil (10,ug / cm 2 ). Secondary electrons
are accelerated by the potential defference
between the foil and the acceleration grid. The
electrostatic field between two grids placed at 45
deg to the ion path defects the electrons 90deg
towards the micro channel plate (MCP) which
has a sensitive area of 1,380 mm 2 • The maindrawback with these designs is such that the gridcan introduce spurious peaks in energy spectra,

U:>/\J Insulating Material

D

Metal

particular ly when elastic yields are very large. In
order to minimize this effect, we used thin wires(Au-W wires of 10,um in diameter with a 1 mm
space) for the grid. The overall transparency isabout 97%.
The performance of the CPD was studied with
5.5 Me V a particles and various ions produced
by a 12 UD tandem accelerator at the Universityof Tsukuba. The ions were elastically scatteredby an 80,ug/ cm 2 197Au target and detected with a
T.O.F system, which was placed at an angle of 8deg. The T.O.F system for these test experiments
consisted of CPD as a start detector and a totally
depleted silicon surface barrier detector (SBD:
100 mm 2 100,um thick) as a stop one. The flightpath was about 20 cm. The signal from the CPD
was fed directly into a constant fraction discriminator (ORTEC 943). The timing signal fromthe SBD was first amplified with a fast preamplifier (IV 48 developed by the electronics department of Hahn-Meitner-Institute).
Figure 2 shows the overall time resolution for
85 Me V 160 as a function of the acceleration
voltage between the foil and the acceleration
grid. It is shown that the time resolution is about
100 ps for Vacc > 0.5 kV and becomes bad withdecreasing the Vacc below 0.5 k V. This is due tothe transit time spread of the secondary electrons
emitted from the foil. The time resolution andthe detection efficiency for various ions are listed in Table 1. The time resolution for 3 5Cl arerather worse than that for 160. This is due to the200

CPD-SBD"........

'"
~
c

150

! t

.S

:i

"§

I !I!

100

~
~

E

50

~
Anode

00.0

0.2

0.4

0.6

0.8

1.0

1.2

Vacc (kV)
5cm

Fig. 1. Schematic drawing of the mirror type channel
plate detector.

Fig. 2. An overall time resolution as a function of Vacc.

158

T. Mizota, et al.

Table 1. Overall time resolution of the CPD·SBD sys·
tern for various ions.
Ion

Energy (Me V)

Time resolution (ps)
(FWHM)

ex

5.5
85
105

167
100
128

16

0
35Cl

effects of the plasma discharge in the SBD 5 ,6) andthe energy straggling of 35e1 ion in the foil.

References
1) W. Startecki, A.M. Steffanini, S. Lunardi, and C.

Signorini: Nucl. Instrum. Methods, 193, 499 (1982).
2) ]. Girard and M. Bolore: Nucl. Instrum. Methods, 140,279 (1977).
, 3) F. Busch, W. Pfeffer, B. Kohlmeyer, D. Schull, and F.
Puhlhofer: Nucl. Instrum. Methods, 171, 7l (1980).
4) T. Nakagawa and W. Bohne: Nucl. Instrum. Methods
A, 271, 526 (1988).
5) M. Moszynski and B. Bengston: Nucl. Instrum.
Methods, 91, 73 (197l).
6) T. Nakagawa and K. Yuasa·Nakagawa: Jpn.]' Appl.
Phys., 29, 498 (1989).

159
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-10.

Timing Property of New Type Time Pick-Up Detector
T. Nakagawa, K. Yuasa-Nakagawa, and 1. Tanihata

In heavy-ion reactions a measurement of timeof-flight is commonly used to determine the massand the energy of a reaction product. For measurement of the flight time, various kinds oftiming detectors are used, for example thin film
scintillators,l) thin 11E solid state detectors,2) andan electron multiplier with a thin film secondary
electron emission foil. In order to minimize
energy straggling and energy loss of particles, adetector with a least amount of material is usually desired. For this reason, the last method
become more and more popular recently. One
setup of this kind is to use a micro-channel plate(MCP) as an electron multiplier (EM), which iscalled a channel plate detector (CPD). Several
authors have reported the good time resolution(:::;: 150ps) for heavy ions 3 - 5) by using this detector.
However the MCP needs a clean high vacuum(:::;: 10- 6 Torr) to prevent breakdown. Therefore it
is not suitable for use under the conditions wherea good vacuum is difficult to maintain. The large
scattering chamber at RIKEN Ring Cyclotron(RRC) Facility meets one of such condition.
Another common method uses a plastic scintillator which is optically coupled to a photomultiplier tube. 6,7) However, because it is very
sensitive to a magnetic field, we can not use it ina strong magnetic field without shielding. In
addition the scintillator is not very compact(length: 20- 30 cm) and needs high voltage up to
10-17kV.
In the present paper we report a new-type timepick-up detector which has a thin foil and aproximity mesh type electron multiplier; presently a developed detector can be operated in a poor
vacuum ('"'-' 10- 4 Torr). Therefore, this time pickup detector is quite suitable for use in the large
scattering chamber at RRC.
Experiments were carried out at Tandem
Accelerator Center, University of Tsukuba. Figure 1 shows a schematic drawing of the detector
and the experimental set up. Ions pass through athin foil made of 20 J1.g/ cm 2 Al evaporated on
Mylar. Electrons emitted from the foil are accelerated by the electric field between the foil
and a grid which is made of a 97% transparent
electroformed mesh. The electrons then run/:::::;:·~).::I Insulating Material

Radioactive#'
Sourceo252ef ~ .

'\.

Metal

',,-

Foil
Grid

ElectronMultiplier

1st Dynode[Anode.":1~li i'i r
L.....J
2cm

Fig. 1. Sectional view of the time pick-Up detector.

through the field free region and strike the firstdynode of an Electron Multiplier (EM) (R2362
Hamamatsu photonics). An electron is multiplied
up to 106 in the EM. The R2362 EM which has 23
proximity mesh dynodes is very compact (max.
length is about 6 cm) compared with other Photo
Multiplier Tube (PMT) and has a high immunity
to magnetic fields.
Fission fragments and 6 MeV a particles of a
252Cf fission source impinge on the thin film at anincidence of 45 degrees. They are then stopped ina standard silicon surface barrier detector (SBD,
100 mm 2 and 150 J1.m thick). The flight path is
7cm. A timing signal is derived from the SBD
through a fast preamplifier (IV 48 developed in
Hahn-Meitner-Institute). The signal was then fed
into a constant fraction discriminator (CFD,TNNEREC 454). The anode signal of EM wasamplified with a Timing Filter Amplifier (TFA,
ORTEC 474) and fed into another CFD. The
vacuum of the test chamber was kept to be about
10- 4 Torr.
The electric potential applied to the firstdynode of the EM and the grid was - 3.5 k V. The
electric potential of the anode was 0 V. The risetime of an output signal was about 2.5 ns. The
typical pulse height for 6 MeV a particles was
about 20 m V. The following components arecontributed to affect the time resolution.
1) Variation in transit time of electrons
between the foil and the first dynode due toa different initial velocities of electrons: 0'0
2) Transit time spread of electrons in EM: O'E

160

T. Nakagawa, et al.

3) Time resolution of SBD: O'SBO
In order to investigate the contribution of 0'0,
we have varied the voltage applied to the foil
( VF ). In Fig. 2, closed circles show the overall
time resolution for 6 MeV a particles as a function of V acc ( = V F - Yo). The time resolution of
SBD for 6 Me V a particles and fission fragments
was below 100 pS.8-10) The observed time resolution is almost independent of Vacc within experimental errors. These results show that the contribution of on and O'SBO is segnificantly small
compared with the total time resolution and thatthe time resolution of 550 ± 50 ps for 6 MeV aparticles is mainly due to the transit time spreadof electrons in EM.

'"
.e
E
..c::

S
I=:

.9

'5 400

'£
e
Q)

E

E=

I

I

I

0.4

0.8

I

1.2

Vacc (kV)Fig. 2. Time resolution of the time pick-up detector as afunction of Vacc. Closed and open squares represent thetime resolution of the time pick-up detector for 6 MeV
a particle and fission fragments, respectively.

In order to evaluate the time resolution of thetime pick-up detector for fission fragments, we
subtracted the contribution of mass and kinetic
energy distribution l l ) from the total time resolution. In Fig. 2, the open circles show the time
resolution of fission fragments (lighter partner)
as a function of Vacc. The time resolution is
improved better with increasing Vacc and thetime resolution remains constant when Vacc
reaches 1 kV. It is therefore considered that thecontribution of on become negligible for Vacc
larger than 1 kV. The on contribute up to about
300 ps for Vacc less than 1 k V.
Figure 3 shows the time resolution of the timepick-up detector as a function of the number of
emitted electrons from the foil, which is evaluated from the experimental results reproted inRefs. 12 and 13. The time resolution is better forincreasing number of emitted electrons, and canbe explained from a simple formula in Ref. 14.
O'E 2 =

(1 + CA 2 (1 - 1/ R) 2) 01// R

where R is the average number of electrons
emitted from the thin film, ~ 2 the variance of thetransit time of a current pulse by a single elec-

...

S
I=:
0

t

"§

'£
e
Q)

E

E=

100

"j

.1

10

100

1000

Number of electronsFig. 3. Total time resolution as a function of the numberof emitted electrons from a thin foil.

tron, and CA 2 the relative variance of the multiplier gain A:
CA

I 800 -

1000

2= O'A 2/ A2

If the large number of electrons are emitted, theO'E2 is proportional inversely to R.
The detection efficiency of the time pick-up
detector for 6 MeV a particles and fission fragments are 85% and 100%, respectively. At thevacuum pressure of 10- 4 Torr, the detector was
sufficiently stable for a long term (about 10 h).
We designed, built, and tested a thin foil timepick-up detector using an electron multiplier. A
time resolution of 550±50 ps and 250±100 ps was
obtained for 6 MeV a particles and fission fragments (light partner) from a 25 2Cf source with theefficiency of 85 and 100%, respectively. The
resolution of the time pick-up detector is mainly
determined by the transit time spread of electrons in an electron multiplier when a high acceleration voltage (> 1 kV) between a foil and an
acceleration grid is applied. If we use an electron
multiplier which has better time resolution, we
will obtain a better time resolution. The timepick-up detector which is described in this paper
is suitable for the measurement of time of flightof heavy ions in a poor vacuum.

References
1) C.K Gelbke, KD. Hildenbrand, and R Bock: Nuc!.
Instrum. Methods, 95, 397 (1971).
2) H. Pleyer, B. Kohlmayer, W.F.W. Schneider, and R
Bock: Nuc!. Instrum. Methods, 96, 263 (1971).
3) W. Starzecki, M.A. Steffanini, S. Lunardi, and C.
Signorini: Nuc!. Instrum. Methods, 193, 499 (1982).
4) J.D. Bowman and RH. Heffner: Nuc!. Instrum.
Methods, 148, 503 (1978).
5) T. Nakagawa and W. Bohne: Nuc!. Instrum. Methods
A, 271, 523 (1988).
6) E. Dietz, R. Bass, R. Reiter, V. Reidland, and B.
Habert: Nuc!. Instrum. Methods, 97, 581 (1971).
7) W.F.W. Schneider, B. Kohlmeyer, and R. Bock: Nuc!.
Instrum. Methods, 95, 397 (1971).
8) T. Nakagawa and K Yuasa-Nakagawa: Jpn.]' Appl.

T. Nakagawa, et al.

Phys., 28, 498 (1989).
9) M. Moszynski and B. Bengston: Nucl. Instrum.
Methods, 91, 73 (1971).
10) H. Henschel, H. Hipp, A. Kohnle, and F. Gonnenwein:
Nucl. Instrum. Methods, 161, 331 (1979).
11) W.H. Schmit, lH. Neiler, and F.l Walter: Phys. Rev.,

161

141, 1146 (1966).
12) K.E. Pferdekamper and H.G. Clerc: Z Phys. A, 275,
223 (1975).
13) l Girard and M. Bolore: Nucl. Instrum. Methods, 140,279 (1977).
14) F. de la Barre: Nucl. Instrum. Methods, 102, 77 (1972).

162
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-11.

Timing Properties af a Time-af-Flight Detector
T. Nakagawa and K. Yuasa-Nakagawa

We have studied the influence of a plasma
effect on the time resolution of a silicon surface
barrier detector. The time resolutions were
measured by changing an electric field strength,
the size of a detector, and the resistivityof a material. The very good timing propertiesof a silicon surface barrier detector (SBD) for
charged particles are utilized by time of flightmeasurements in nuclear reactions. I - 3 } However,from many experimental investigations, it is wellknown that a timing signal obtained from a SBD
may not represent the correct time arrival of anion in the detector, as it usually is too late(Plasma Delay Time (PDT)).4.5) Recently the time
resolutions of SBD were studied by Mozynski
and Bengston. 6 ) They have reported that thedependence of the time resolution of SBD on anelectric field strength and interpreted it in termsof plasma discharge, but not studied for thevarious conditions of the SBD. The purpose of
the present experiment is, therefore, to survey
the plasma effect under the various conditions.
From present measurement we discuss a relation
between PDT and the time resolution of SBD.
The experimental setup is shown schematically in Fig. 1. It consists of a CPD as a startdetector and a SBD as a stop detector. The flightpath between the CPD and SBD is 70±0.5mm.
The CPD consists of an electron-emitting foil
and two channel plates (25 mm in diameter) witha central hole (6 mm in diameter) and without
any grid.7} A secondary emitting foil, two channel plates and an electron-collecting anode aremounted on the common axis and placed perpendicular to the ion path. In order to enhance theelectron emission, magnesium oxide (15 ,ugl cm 2 )is evaporated onto a formvar foil (10 ,ug/ cm 2 ).
The timing signals froms the SBD were first
amplified by a fast preamplifier (IV 69B) and afast amplifier (IV 64) with a rise time of less than
0.8 ns (both developed at the Hahn-Meitner Institute). These signals were fed into a constantfractional discriminator (CFD, ORTEC 943). The
signals from the CPD were fed directly into the
CFD. Throughout the measurements, the time
range of the time-to-amplitude converter (TAC)
was set at 50 ns. In order to test the plasma delay

Channel Plate
Detector

CHANNEL
PLATESFOIL
Surface Barrier
Detector

ANODE,

COLLIMATOR({]~ r-_-.:E--_ _ _ _....=.B::.:.EA::..:.M_
lcm
LW

Fig. 1. Schematic drawing of the channel plate detector
with a central hole.

time and the time resolution of SBD, we used the8.78 MeV alpha particles of a ThC' source.
In order to test the dependence of plasma delay
time on the properties of SBDs, we used two
different SBDs (Det. 1: S = 300 mm 2 , T = 179 ,u m,
p=2,3000cm C"'-'180 pF, VN =180 volt, and Det.
2: S=50mm 2 , T = 500 ,urn, p=6,l000cm C-----l1.5
pF, VN = 170 volt), where S, T, p, C, and VN are
the area, thickness, resistivity, capacitance andrecommended bias voltage of the SBD, respectively. The time-zero calibration was performedby varing the field strength F. As early as 1966,
Meyer proposed the linear dependence of theplasma time on an inverse field. N eidel andHenschel showed that this holds as well for theplasma delay, and that by extrapolation to infinity of a high field strength (II F ~O), the plasma
delay vanishes. 4 } The plasma delays of two detectors are shown in Fig. 2 as a function of I I F eff ,which is given
1000

.-..
E;

800

~
'J:j

600

U)

~

0)

"C

Det.l

~I

400

i i

i

Det. 2

C<S

S

U)

aam a

200

C<S

Il::

0
0.0

0.4

0.8

1.2

a a~
1.6

2.0

lIFeff (cmlke V)

Fig. 2.

Plasma delay time as a function of Ferr .

163

T. Nakagawa, et al.

Feff = Cd - x) / Ji't,
where d = (2'tJi V) 1/2 is the depletion depth at agiven bias voltage V, Ji = 1,481 (cm 2 V- 1s- 1 ) is theconstant electron mobility and 't = P X 10- 12 (s)with the resistivity of a material p (Ocm); x is
taken at the charge centroid of the ionization
track produced by a charged particle. The
charge centroid for 8. 78 MeV alpha particles canbe estimated at 2/3 of the range calculated by
Ref. 8. The plasma delay time of Det. 2 is quite
small (about 200 ps). The difference between thetwo detectors is mainly due to the effect of
capacitance. S)
Figure 3 shows the overall time resolution of a
T.O.F. detector which consists of a CPD and SBD(Det. 2) as a function of bias voltages. The
overall time resolution (O"'total) was determinedby the following components: time resolution of
CPD (O"'CPd), contribution of noise to the time
resolution(O"'noise) and intrinsic time resolution of
SBD (0"'5BD). Then, O"'total is given by

(1)
150

8'"
~

0
'.0

;:j

~

100

Q)
I-<
Q)

S

~

50
100

200

300

400

500

Bias voltage (volt)

Fig. 3. Overall time resolution of the T.O.F. detector as
a function of detector bias.

the property of SBD. The time resolution of SBD
corresponds to about 20% of the plasma delay
time within the experimental error.
150...-------------,

O~~~~~~~~~

0.0

0.5

1.0

1.5

2.0

2.5

3.0

lIFeff (cmlke V)

Fig. 4. Intrinsic time resolution of SBD as a function ofFerr .

We obtained the best time resolution of 80 ps
for 8. 78 MeV alpha particles using a simple
detector system which consisted of a small
capacitance surface barrier detector and a channel plate detector with a central hole. We foundthat the plasma delay time is strongly dependent
on the detector properties such as the resistivity
and capacitance described in Ref. 5. The time
resolution of the surface barrier detector for 8.78
MeV alpha particles is also strongly affected by
the electric field strength and the properties of
the SBD. The time resolution is about 20% of the
PDT. In order to get a good time resolution using
the surface barrier detector, it is better to have asmall capacitance with low resistivity and overbiasing.
References
1) W. Strazechi, A.M. Steffanini, S. Lunaridi, and C.

To detetmine the noise contribution, we used apulser at a fixed amplitude. In this way, the time
resolution was obtained as 50 ps. In order toinvestigate the time resolution of CPD, two identical CPDs were used as a start and stop detector.
The overall time resolution was about 80±5 ps.
Owing to the basic symmetry of the experimental
device, we could obtain the time resolution ofeach CPD by dividing the previous width by /2.
Thus, we obtained the time resolution of 56 ps for
8.78 Me V alpha particles.
Figure 4 shows the O"SBD (0"5BD 2 = O"'total 2 - O"'CPd 2 O"noise 2) as a function of 1/ F eff • The intrinsic time
resolution of SBD decreases with increasing F eff •This tendency is also seen for the plasma delay
time. The time resolution of Det. 2 is smaller
than that of Det. 1 at the same Feff • This is due toSignorini: Nucl. Instrum. Methods, 193, 499 (1982).
2) E.c. Pollaco, lC. Jacmart, Y. Blumenfeld, Ph.
Chomaz, N. Frascaria, J.P. Garron, and J.C. Poynette:
Nucl. Instrum. Methods, 225, 51 (1984).
3) A.M. Zebelman, W.G. Meyer, K. Kalbach, A.M.
Poskanzer, R.G. Sexteo, G. Gabor, and D.A. Landis:
Nucl. Instrum. Methods, 141, 439 (1977).
4) H.-O. Neidel, H. Henschel, H. Geissel, and Y. Laichter:
Nucl. Instrum. Methods, 212, 299 (1983) and references therein.
5) W. Bohne, W. Galster, K. Grabisch, and H. Morgen·
stern: Nucl. Instrum. Methods A, 240, 145 (1985).
6) M. Moszynski and B. Bengtson: Nucl. Instrum.
Methods, 91 73 (1971).
7) T. Nakagawa and W. Bohne: Nucl. Instrum. Methods
A, 271, 71, 523 (1988).
8) L.C. N orthc1iff and R.C. Schilling: Nucl. Data Tables,
7 (1979).

164
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-12.

Compact and Gridless Channel Plate Start Detector
T. Nakagawa and W. Bohne*

Mass identification in heavy ion reactions isoften performed by using the time of flightmethod. A start detector as thin as possible isrequired to avoid energy loss and straggling ofparticles. For many years arrangements of secondary electron emitting foils and a micro channel plate (MCP) have been used successfully. The
majority of these electrons have low energies
and are ejected in all directions from very thin
foil when the ion path through the foil and they
have to be transported isochronously to a channel plate. In several constructions this isachieved by placing an acceleration grid directly
behind the foiP - 3} All detectors of this type haveserious disavantage that ions are stopped orenergically degraded and scattered by the inhomogeneous material of the grid. Taking thisproblem into account, we have chosen and testeda system where the ion path through a central
hole in the MCP and anode similar to the ones
developed by Oed, et al. 4 } To avoid any inhomogeneous material in the beam path, however, we do the electron transport without a wire
between the foil and MCP.
Figure 1 shows a schematic drawing of thedetector design. A secondary electron emitting
foil, two MCP's with a central hole (6 mm indiameter) and an electron collecting anode alsowith central hole (5.9 mm in diameter) are
mounted on a common axis and placed perpendicularly into the ion path. All parts are made ofmetal or ceramics to exclude any plastic material near channel plate. In order to enhanceelectron emission, magnesium oxide (15.ug/ cm2)
is evaporated on a formvar foil (10 .ug/ cm 2) . The
secondary electrons from this foil are accelerated toward the channel plates by the pot,e ntial
deference between the foil and the front surfaceof the first channel plate (VF = - 3.9 k V, Vc p =- 2.8 k V) . A potential ring is placed between the
foil and the channel plates to increase the vertical velocity component of electrons (VR = 0 V).
Its voltage was chosen to optimize the electron
collection on the channel-plate ring. Furthermore* Hahn-Meitner-Institut-P Berlin, D-1000 39, Postfach
390128, F.R. Germany.

FO IL

CHANNEL
PLATES
ANODE

BEAM

~
CERAMICS

LLJ
1cm

Fig. 1. Schematic drawing of the coaxial timing detector.

the foil is not mounted parallel to the channel
plate surface but with a small angle of approximately 6 deg. This help to disturb a little bit thesymmetric electric field between foil and channel
plate to reduce the fraction of the central part ofthe beam spot from which no effective electron
collection is possible. All test measurements are
performed together with a standard surfacebarrier detector (SBD) as a stop detector. For
radioactive sources we used a 500 .um thick SBD
of 50 mm 2 at 10 cm behind the CPD. In experiments with a beam from a heavy ion accelerator
VICKSI, a time-of-flight spectrometer consists ofthe same CPD at 35 cm from the target and a 100
mm 2 large SBD of 150 .um in thickness; the flightpa th between both detectors was 90 cm.
The experiment with radioactive source wasdone in Hahn-Meitner-Institut. Most of the test
measurements were carried out with a collimated ThC' a-Source. The electric potential applied
to each channel plate was always 1.1 kV. The
maximum detection efficiency for a-particles
was 50% with a time resolution of 90 ps. For
fission fragments of 25 2Cf, the detection efficiency
was always 100%. In an experiment with 840
MeV and 710 MeV 32S beams from the VICKSI
accelerator, elastically scattered at a thin foil

T. Nakagawa, et at.

32S

~
C

:l

+ 58NiE(.32S)=710 MeV
15

2 < v<4 cm/ns

-eo
~10
1)

c1)

~ 5
1)

20

60

40
A

[amu]

Fig. 2. Mass spectrum of the fusion evaporation reactionof 32S+58Ni for a velocity window between 2 and 4 cm/
ns at 8. Bb = 4 deg.

(200 j1.g/ cm 2 ) gold target, we achieved a total
time resolution of 60 ps with an efficiency of
70%. The time resolution is not collected for 'velocity variations due to the energy-loss straggling in the target and formvar foil. If the signals
from the channel plate anode are not fed directly

165

into a constant fraction discriminator, but are
amplified by a very fast preamplifier with a risetime of 95 ps and a gain of 10 dB (IV 70, developed by the Hahn-Meitner-Institut) efficiencies
of almost 100% for 32S ions and 90% for ex
particles are possible, virtually without any deterioration of the time resolution. Figure 2 shows apart of a typical mass spectrum of the fusionevaporation reaction measured with a flight pathof 1.1 m. The detection efficiency was about
100%.
References
1) W. Startecki, A.M. Steffanini, S. Lunardi, and C.
Signorini: Nucl. Instrum. Methods, 193, 499 (1982).
2) J. Girard and M. Bolore: Nucl. Instrum. Methods, 140,279 (1977).
3) F . Busch, W. Pfeffer, B. Kohlmeyer, D. Schull, and F.
Puhlhofer: Nucl. Instrum. Methods, 171, 71 (1980).
4) A. Oed, G. Barreau, F. Gonnenwein, P. Perrin, C.
Ristori, and P. Geltenbrot: Nucl. Instrum. Methods,
179, 265 (1981).

166
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-13.

A Position Sensitive Ionization Chamber

Y.H. Pu, T. Nakagawa, K. Yuasa-Nakagawa, T. Mizota,
H. Fujiwara, M. Ogihara, and S.M. Lee

For last years, a large ionization chamber for
identifying charge number of reaction products
has become widely used in heavy-ion physics. 1 - 3 )This chamber can be built in a large dimension,and the energy and energy loss resolutions
achieved with them are comparable to that ofsolid state detectors. In order to obtain a largesolid angle and information on scattering angles
of reaction products, we constructed and tested acompact and large area position-sensitive ~E-E
counter telescope which consists of an ionizationchamber as a ~ E counter and a large area solidstate detector as a E counter (effective area 2,000mm2).
Figure 1 shows a schematic drawing of theGrid frame
Anode

---.

SSD
\

Entrance window

Cathode5cm

Fig. 1. Schematic drawing of a position sensitive ionization chamber.

Table 1. Energy-loss resolution for various ions.
Ion energy
(MeV)
a

5.5

28Si

90.0

Gas pressure(Torr)

Energy-loss(keV)

Energy loss resolution(keV, FWHM)

20
30
30

520
840
1130

54 (10.3%)
82 ( 9.7%)
435 ( 4.0%)

ionization chamber. The distance between a frisch grid and an anode is 2 cm. The distance
between the grid and the cathode is 8 cm. The
frisch grid consists of Au-W wires of 50 .urn indiameter at a distance of 1 mm. The shieldinefficiency 4) for positive ions, which exist
between the grid and the cathode, by this grid isabout 2%. According to the experiment conditions, the effective length of the ~ E counter canbe changed from 0 to 10 cm. In order to minimize
the effect of energy straggling and energy loss inan entrance foil, we used a thin foil (45 J1 g/ cm 2 )supported by a mesh grid. The E counter isa large area ion-implantation solid state detec-

E-LlE
Drift Velocity (cmJ~sec)Fig. 2. Position resolution as a function of the drift
velocity of electrons between a grid and a cathode at
30 Torr.

Fig. 3. Energy loss (Ll E) vs. energy (E- Ll E) for
heavy residues produced by bombarding a target 27 Al2
0 3 with 90 MeV 28Si. Particles are detected at 10 deg.
Isobutane of 30 Torr was used as a counter gas.

167

Y.H. Pu, et al.

tor (4.5 X 4.5 cm 2) made by HAMAMA TSU
Photonics. The performance of the A E-E telescopes was studied with 5.5 MeV a particles and28Si beams produced by the 12 MV UD tandem
accelerator in University of Tsukuba. The ionsare elastically scattered by a 100 J.lg/ cm 2 197Au
target and detected in an ionization chamber
placed at an angle of 10deg.
The energy-loss resolutions for 5.5 MeV alphaparticles and 90 MeV 28Si ions are listed in Table
1. These values are comparable to an empiricalformula of energy straggling in the isobutane
gas.I)The position of incident particles is given fromthe drift time of electrons between the path of theincident particle and the frisch grid. Figure 2
shows the position resolution as a function of thedrift velocity of electrons between the cathodeand the frisch grid. The position resolution was
improved with decreasing the drift velocity. The

full and dashed lines correspond to the time
resolution of 16 ns and 5.6 ns, respectively. The
best position resolution of 0.25 mm for 28Si (EL =90 MeV) has been obtained at 30 Torr.
Figure 3 shows a two-dimensional nuclear
charge Z spectrum for the reaction products of
90 MeV 28Si + A1 20 3 •References
1) K. Kusterer, ]. Betz, H.L. Harney, B. Heck, Liu Ken
Pao, and F. Porto: Nucl. Instrum. Methods, 177, 485(1980) .

2) ]. Pochodzella, R. Butsch, B. Heck, G. Hlauatsh, A.
Miczaika, H.J. Rabe, and G. Rosner: Nuc!. Instrum.
Methods A, 234, 97 (1985).
3) K.D. Schilling, P. Gippner, W. Seidel, F. Stary, E.
Will, K. Heidel, S.M. Lukyanov, Yu.E. Penionzhkevich, V.S. Salametin, H. Sodan, and G.G. Chubarian: Nucl. Instrum. Methods A, 257, 197 (1987).
4) 1. Ogawa: Radioisotope (ed. F. Yamazaki), Kyouritsu
Shuppan, Tokyo, p. 135 (1973) (in Japanese).

168
RIKEN Accel. Prog. Rep. 22 (1988 )

111-5-14.

Performances of a Two-Dimensional Position-Sensitive
Silicon Detector with a Large Effective Area

K. Munakata, T. Kohno, T. Imai, A. Yoneda, T. Doke, ]. Kikuchi,
H. Murakami, T. Yanagimachi, N. Hasebe, and K . Nagata
For the observation of the elemental andisotopic compositions of cosmic-ray heavy particles by a l:1E-E telescope, a two-dimensional
position sensitive detector (PSD) with a large
effective area plays an essential role in realizing
a large acceptance angle of a telescopeY Recent·ly, new large PSDs (62 mm x 62 mm) have beendeveloped in collaboration with Hamamatsu
Photonics Company and exposed to cyclotron
beams. In this report, we briefly summarize thecharacteristics of the new PSD.
The PSD is a sillicon solid-state detector of an
ion-implanted type of 400 ,um in thickness andjunction capacitance of 500 pF. The position of
an ion on PSD is reproduced by taking a linear
combination of four signals from electrodes atthe corners of an ion-implanted anode, where thesurface resistivity and the line resistivities of the
strips at the four sides are formed. 2 ) The energy
deposited in PSD is also reproduced by taking asum of these four signals. To test the characteris·tics of the PSD, we used a N beam with 85 MeV.
In front of PSD, we placed a 2 mm thick alminium collimator with 0.5 mm if> holes on 13 x
13 lattice points at 5 mm intervals. A main beam
was scattered with a 1 ).lm Au foil target, and a
detector system was set at a 300 scattering angle.

Pulse height signals from PSD are amplified andrecorded on a micro-computer through a
CAMAC system. Three different pulse shaping
time constants of 3, 6, and 10 ,us were tested.
An example of position data is shown in Fig.
l(a), where each spot represents N ion passed
through a hole on a collimator located in front of
PSD. In Fig. l(b), we plot the displacement
vectors of each spot from the center of each holeon the collimator. The distortion of a twodimensional pattern clearly increases near theedge of a 62 mm X 62 mm PSD. This distortion
mainly arises from non-linearity of ADC aroundthe pedestal. When a simple linear conversion
from the ADC-channel to energy is assumed
regardless this non-linearity, the small signals
from the electrodes far from ion track are overestimated. Owing to this overestimation, reproduced positions are shifted to the inside of
PSD. We confirmed that this distortion can bemarkedly suppressed by using non-linear conversion from the ADC channel to energy. It is also
noteworthy that this distortion can be easily
reformed by regulating the position of ions basedon the displacement vectors in Fig. l(b). In thefollowing analysis, we eliminated the distortionin this manner.

62mm
~.

~. .~, \~~" -, "" ~, "9 'Ii... .,. ':" ~

~

,

.~

" . '.~ :1 .,,.

It "i:

;t;

'.

·f .

,If ,;, .,; .

,.., ~,Ai"~" .1'",1..~. " :. ",, "", ~

~.

t-

~

~

f.I

. ' .. .-j'

'ft

<t.

".

III

.•

.;I:

)1'.

' '':

~

-'I. "',

,~

....

'\-.!

•.,

... -.:..-;~~...

.. .,. .... . ........

. '

III

~

"•

•

'.

'Itt

Or.

If

_..

~

.....

..

.

,..

.... ,,...,.

..:

...

tI'"

•...,

-IJ

,If'!

~.

.•

..

~ . ... ~. .

: . ;: .: ; .: : : : :. ~. .,:..: "<:; ! ~:t t ,l' :: ;' .: :; .:: ,~ :\~Ca)"" I '--,..
"._- :-r--

I

I

I'

---

i

""" r-+-

--

:

---

,1-.....,

!

,I"

J
...... 1.../11//1 ......

I-- l<-.. .. 41:foo '..

1"- '\ 1\

\

V / V

\

/ V/

"- I"

-"'1-""\ \ I'"\

Cb)

Fig. 1. Distortion in the two-dimensional pattern for 85 Me V N ions. The pulse
shaping time is 6 j.lS. In front of 62 mm X 62 mm PSD, a multi-slit collimator with 13 x
13 holes of 0.5 mm ~ is located. a, Position data for 85 MeV N ions; b, Displacement
vectors of each spot in (a) from the center of each hole on collimator. This patternis essentially unchanged for other shaping times.

169

K. Munakata, et al.
4000 _T= 3IJs

1 0IJs

-

-2

I0

0

10 00

1000

-

10IJs

(mm)

1000
40

80

+2

741IJm

1 20
(MeV)

-2

(mm)

+2

10 00

6IJS

61ls

I3000 l-

-2

(mm)

+2

-2

(mm)

+2

Il-

5851lm1000

I-

590\Jm
10 00

3IJs

3\J s

ttO

0

40

80

\

-2

120
(MeV)

(mm)

+2

-2

(mm)

+2

Fig. 3. The position resolutions in x and y coordinates
for three shaping timer of 10, 6, and 3 j.lS. Plotted arehistograms of difference between reproduced coordinate of ion and that of the center of hole passed by theion. The FWHMs of these histograms are calculated byfitting the Gaussian distribution and indicated.

4000 l-II---

O L-~~~~~\~~~
40

80
120
energy (MeV)
(a)

(b)

Fig_ 2. Spectra and spatial distributions of energy loss
on PSD. Three shaping times of 10, 6, and 3 j.lS aretested. a, Energy spectra for three shaping times; b, The
equal energy loss contours on PSD for three shaping
times. These contours are derived from average energy
losses of ions passing through each hole on the collimator. The numbers attached to contour lines represent the difference in energy loss from 85 Me V inpercentage.

Figure 2(a) shows the energy spectra of N ionsin PSD for three shaping time constants of 10, 6,
and 3 j1.S. It is obviously seen that the main peakof Fig. 2(a) shifts toward lower energies withdecreasing shaping time constant. This is due tothe fact that the time necessary to collect thewhole charge deposited on PSD varies with theion position on PSD. To show this more clearly,
we plot in Fig. 2(b) the equal energy loss contours
on PSD. The numbers attached to contour lines
represent the deviation from 85 MeV in percentage. It is clear that the charge deposited on theposition closer to the edge of PSD is more effectively collected for each shaping time and theaverage distribution of collected charge becomes
more uniform with increasing shaping time.
The x and y position resolutions of PSD are
shown in Fig. 3, where plotted are the histogramsof difference between reproduced coordinate ofeach ion and that of the center of the hole on
collimator passed by the ion; the FWHM of eachhistogram is indicated. The position resolution isclearly improved with decreasing shaping timeand, at 3 j1.S, the FWHM becomes comparable to
the radius of the hole on the collimator (0.5 mm~). This is due to the fact that the fluctuation
arising from a low frequency noise such as athermal noise is considerably suppressed for such
shorter shaping time.
References
1) T. Kohno: Space Sci. Rev. (1989), in press.
2) T. Doke, J. Kikuchi, H. Yamaguchi, S. Yamaguchi,
and K. Yamamura: Nucl. Instrum. Methods A , 261,
605 (1987) .

170 'RIKEN Accel. Prog. Rep. 22 (1988)

111-5-15.

Calibration of Si-Detector Telescopes for Heavy-Ion
Measurements in Space

N. Hasebe, T. Doke, T. Kashiwagi, ]. Kikuchi, T. Kubo,
W.P. Liu, H. Murakami, A. Nakamoto, K. Nishijima,
T. Suzuki, 1. Tanihata, T. Yanagimachi, and M. Yanokura

Silicon detector telescopes with extremely
large geometric factors will be boarded in the
GEOTAIL satellite scheduled to be launched in
1992 to observe elemental and isotropic compositions of solar energetic particles with 2 ~ Z ~ 30
in a wide energy region from 3 Me V In to 210
Me V In. The telescopes consist of several layersof Si-detectors, of which top two layers are
newly developed position-sensitive silicon detectors (PSSDs) . The PSSDs provide twodimensional position information so that an
accurate measurement of a path length can beobtained in each layer. The PSSDs also measure
the energy losses with the following Si -detectors.
The use of the PSSDs as dE -detector enable us torealize the large geometric factor of the telescope.
To achieve an excellent mass resolution and awide aperture in the telescope, a good positionresolution, a position-linearity, and uniformity ofthe detector thickness must be attained.
In previous experiments using nitrogen beams
from the cyclotron, the characteristics of the
PSSDs such as position linearity and position
resolution were measured and excellent linearity
and resolution as well as those expected from thetheoretical estimation were obtained. 1 - S ) Experiments made in FY 1988 were focused on theuniformity of detector thickness which is crucial
to identify isotopes of ions.
In the present experiments, two kinds of
PSSDs were tested by using Ar, Ca, and Zn
beams from RIKEN Ring Cyclotron. One (hereafter reffered to as PSSD1) is 30 mm X 30 mm insize and 100 ,urn in thickness. The other (hereafter PSSD2) has four sensitive segments, that is,
one silicon wafer is divided into four segments,
because a thin detector has an extremely large
capacitance. The size of each segment is 13
mmX 13 mm and its thickness is 50 ,urn.
In addition to these dE- and E-signals, theTOF and B X r formation were obtained fromother experimental setup (PPAC) used at thesame time. From these information, the charge
state, Q, and the mass, A, of the ions were simultaneously determined and accurate isotope separation was achieved consequently.
Experiment-I:
The telescope consists of PSSDI as a dEdetector, a thick E -detector, and an anticoincidence detector. The beam energy of Ar and
Ca used in the experiment was 26 MeV In. The
charge distribution of reaction fragments
obtained by Ca beam is shown in Fig. 1. The
charge resolution is esimated to be about 0.15
charge unit in rms. From the energy loss measurement, the non-uniformity of the thickness(thickness variation) was estimated to be ± 2.5,urn when expressed in peak to peak value. In the
restricted region smaller than 10% of the wholearea, the thickness variation is less than 1.3 ,urn,which agrees with the result obtained by the
Cu-beam experiment performed in FY1987.
Experiment-2:
The telescope consists of PSSD2 as dEdetector, a 400,um thick PSSD as E-detector, andan anti -coincidence detector. The beam energy of
Zn used in the experiment was also 26 MeV I n.
H15

Z

al
'\

~

:J

o

U

,.

o~:~::
166_ 0.:0• •~'.: .~.'•';~.;~:-.":":",

i:.~-;-= ~603

Fig. 1. Nuclear charge histogram obtained byExperiment-I. A Ca-beam is bombarded to a Be-target
and various fragments produced are shown. The
charge resolution is about 0.15 charge unit in rms.

N. Hasebe, et al.

(,

i\

,\

./\

.1'

j\

.J\

j\

.J '.

,./\

•.i'"·.,; .....

,.

.-.....-/.\,.,/"\..A..

..,-......

./\.

j\

/\...

.....

-=

~

•r"\,.

p,...r"'"

-

-,\

....

RING EXPH26MeV/n Zn) dE spectra by SBum PSD (Left).

j\

;.~

ji

) "

j\.

j\.

.J"'.
./\

j'\.

RING EXPH26MeV/n 2n) dE spectra b\l SBum PSD (Ri~ht),

Fig. 2. Energy loss distribution of Zn-ions of 26 Me VI
n in PSSD with the thickness of 50 .urn. The PSSD has
four position-sensitive segments. These show the
thickness variation of each segment of the detector.

Table 1. Variation in the detector thickness of PSSD
expressed in peak to peak.
EnergyPSSDBeam(MeV I n)
Zn

Thickness

Variation(.urn)(.urn)

Sg-l 50
1.8
Sg-2 50
1.7
Ca/ Ar
26
100
2.5
Cu
16.7
100
1.3
N
Sg-l 25.2
5/ 6
1.1
Sg-2 25.3
0.8
Sg-3 24.4
0.7
N
Sg-l 50.1
5
0.9
Sg-2 50.4
0.8
Sg-3 49.4
1.0
PSSDs with 25 and 50 .urn in thickness have four segments in each wafer.
26

171

Two among four sensitive segments of PSSD2
were tested. Energy loss distributions of Zn ionsfor PSSD2 are shown in Fig. 2. The variation ofpeak position of the distributions corresponds tothe thickness variation of the detector. The nonuniformity of the thickness was ± 1.8,um in peak
to peak value and the difference in average thickness between two segments was less than 0.2%_
This result is not in consistent with that obtainedwith a nitrogen beam of 70 MeV in FY1988 .
The results of both experiments summarized inTable 1 indicate that there exists the nonuniformity of the detector thickness of 1- 2 ,urn
for the second models of the PSSDs. The value(peak to peak) must be reduced to be less than 1,urn as the goal. The non-uniformity in detector
thickness obtained in the present experiment
seems to be caused by the non-uniformity in thelapping and/ or etching processes in fabricationof Si -detectors.
In the first model of the PSSD, there was alarge position deformation of the imaging pattern as reported in 1986.1> In the second model ofthe PSSD, the position linearity has been greatly
improved by a new approach in which the four
corners of the resistive electrodes are connectedwith low resistive strip lines. In the second
model, uniform thickness to identify their irongroup isotopes has not yet sufficiently been
attained though the excellent position performance has been achieved. 5 ) In the next stage of
the PSSD-development, we are planning to make
PSSDs paying a special attention to the lappingand etching processes in the detector fabrication.
References
1) T. Doke, et al.: RIKEN Accel. Prog. Rep., 20, 122(1986) .
2) T. Kohno, et al.: RIKEN Accel. Prog. Rep., 21, 152(1987) .
3) T. Doke, J. Kikuchi, H. Yamaguchi, S. Yamaguchi,
and K. Yamamura: Nucl. Instrum. Methods A, 261,
605 (1987).
4) N. Hasebe, Y. Ezawa, H. Yoshii, and T. Yanagimachi: jpn. ]. Appl. Phys., 27, 816 (1988).
5) T. Yanagimachi, et al.: Nucl. Instrum. Methods(1989), in press.

172
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-16. Measurements of Some Characteristics ofThin Position-Sensitive Silicon Detectors
K. Nagata, T. Doke, J. Kikuchi, K. Nishijima, T. Kashiwagi,
T. Kohno, T. Imai, K. Munakata, A. Nakamoto,H. Murakami, T. Yanagimachi, and N. Hasebe

To observe elemental and isotopic compositions of solar flare particles, silicon detector
telescopes with extremely large geometric factors are planned to be used in the GEOT AIL
mission scheduled to be launched in 1992. To
realize such telescopes, the development of
position-sensitive silicon detectors (PSSDs) witha good position linearity and resolution wererequired. Recently we succeeded in developing of
new PSSDs which meet such requirements. However, the PSSDs were planned to be used as.dE -detectors, too. To achieve an excellent mass
resolution, the non-uniformity of the detector
thickness must be kept less than ± 1 % for thin
PSSDs to be used as MI -sensors. In this experiment' we investigated the non-uniformity in25}J11 PSSD 11th 18 JIll AI ibsorberdE spectr&(1,1,2H4,4,2)

Fig. 1. Schematic view of a positionsensitive silicon detector (PSSD).

25 JlIA PSSD 11th 18}JIA AI ibsorber

Riken
PSSD

1988

25

Nitrogen

25 JJIA PSSD

18 JlIII AI IbsorberdE spectrl(1,1,3H4,4,3)

May

MICRON,5

MeV/n

dE spectrl(1,1,1HM,1)

Fig. 2. Pulse height distributions of energy losses measured by an 84 MeV nitrogen beam for a 25 .urn thick
PSSD.

173

K. Nagata, et al.
DeLta-E

DeLta-E (MeV)
50 micron PSD
84. O· MeV N(MeV)

25 micron PSD
84.0 MeV N<0.95< 0.950.95-0.97

0.95-0.97

0.97-0.99

0.97-0.99

0.99-1.01

0.99-1.01

1.01-1.03

1.01-1.03

1.03-1.05

1.03-1.05

>1.05

>1.05

(b)

(a)

Fig. 3. Two-dimensional maps of detector thicknesses.
(a), a 25 ,urn thick PSSD; (b), a 50 ,urn thick PSSD.

detector thickness for two kinds of PSSDs withdifferent thicknesses by measuring the energy
losses of 70 MeV and 84 MeV nitrogen beams.
The PSSDs tested are rectangular type detectors
and each detector is divided into four segments
as shown in Fig. 1, because a thin detector has anextremely large capacitance. The size of thesegments and their thickness for tested PSSDs
are shown in the following.
Thickness (fJ. m)
Size (mm x mm)
25
13 x 1350
22 x 22
The segment has four point-electrodes at eachcorner. The position signals are obtained fromthe arithmetic calculations of four pulse heightsfrom the point electrodes. 1,2) On the other hand,the energy loss signals are obtained from theback side electrode, that is, the opposit side to
the position sensitive surface. The residualenergy after passing through PSSD is measured
with a 0.3 or 0.4 mm thick position sensitive
detector. A typical distribution of the energy
losses in three segments of a 25 fJ.m thick PSSD
is shown in Fig. 2. The energy loss sprectra in the
fourth segmant were not measured because of alack of signal cables from the scatterring chamber. Each segment is divided into 16 areas, andby using position information for incident parti-

c1es from PSSD, we obtained an energy loss
spectrum for each area. Figure 2 shows theresult. However, these are not raw data, but the
spectrum in each area shows only their neighbourhood of the peak. The difference in the peak
position gives the average detector thickness inthe area. Thus, we can draw the 2-dimensional
map of detector thicknesses.
Figure 3 (a) shows thus obtained two dimensional map of the detector thickness in a 25 fJ.m
thick PSSD, and Fig. 3 (b) shows that in a 50 fJ.m
thick PSSD. In these maps, we assume that the
average thickness in all three segments (48areas) is unity. These results show that the thickness in the 25 fJ. m thick PSSD ranges from 0.95 to
1.05 and that in the 50 fJ.m thick PSSD from 0.97
to 1.03. On the other hand, our final goal on the
thickness uniformity is 0.99-1.01. Thus, the above
results are still worse than expected.
References
1) T. Doke, J. Kikuchi, H. Yamaguchi, S. Yamaguchi,

and K. Yamamura: Nucl. Instrum. Methods A, 261,
605 (1987).
2) T. Yanagimachi, T. Doke, N. Hasebe, T. Imai, T.
Kashiwagi, J. Kikuchi, T. Kohno, W.P. Liu, K. Munakata, T. Motobayashi, H. Murakami, K. Nagata, A.
Nakamoto, and H. Yamaguchi: Nucl. Instrum.
Methods A, 275, 307 (1989).

174
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-17.

Test of a Si Two-Dimensional Position-Sensitive Detector
for Unbound Particle Measurements
M. Ogiwara, K. Ieki, Y. Ando, N. Iwasa, and H. Murakami

In detection of unbound particles emitted in
medium-energy heavy-ion reactions, accurate
measurement of the relative momenta between
decaying particles is important. The energy andposition of the particles should be determined
precisely and the charge and mass of the particles should be identified correctly. A large area
detector array of L1 E-E counter telescopes of Si
solid-state detectors (SSD's) is most usefull)
because of their good detection efficiency. Two
dimensional position sensitive detectors (PSD's)
can be used as L1 E counters. Recently, a very
good position resolution and a position linearity
are reported 2 ) for such large area PSD's with line
resistance at four sides. For correlation experiments, however, PSD's with line resistance are
not suitable because a good time resolution of
the detector is also required to avoid accidental
coincidence. We, therefore, tested another typeof PSD, made by Hamamatsu Photonics, withelectrodes at four corners. The PSD is of an
ion-implanted type with a sensitive area of 45mm X 45 mm and 300 J1. m in thickness. The PSD
and an E counter with the same area and 2,000
J1.m in thickness constitute a counter telescope.
The test was performed with a 45 MeV 4He
beam and a 84 MeV 14N beam from the cyclotron.
Elastically scattered particles with a 4 J1.m Au
foil target were collimated by a 1 mm brass platewith 5 x 5 holes of 0.7 mmq) and detected with thecounter telescope located at 25° from the beamaxis and 30 cm from the target. Adjacent holes inthe vertical and holizontal directions have a 10
mm distance.
Since the charge collection of the electrodes isknown to be rather slow and position dependent 2 )in large detectors, we studied the ballistic deficit
by changing the shaping time constant T of ashaping amplifier to be 0.5, 1, 2, 3, and 6 J1.S. For
cases of insufficient charge collection, peak splitting was observed in the energy spectra obtainedby summing the outputs of the four electrodes.
We found that ballistic deficit is negligible forthe data with T=3 J1.s, which is far shorter thanthe case of PSD's with line resistance.
The incident position of the particles can becalculated from the charge signals from the fourelectrodes. Using a simple formula like (1) or (2)of Ref. 2, we observed a large distortion of theposition. We propose, therefore, following formulas. The origin of the coordinate (0,0) is set atthe center of the detector. Four charge signals Qi(i = 1, 2, 3, 4) are from the electrodes located at(1, 1), (-1, 1), (-1, -1), and (1, -1), respectively. The position (X, Y) can be expressed by2A
X 1+ Jl-2(A2+B 2)
2B
Y 1 + Jl-2 (A2+ B2)
A = (- 51 + 52 + 53 - 54) / C
B = (- 51 - 52 + 53 + 54) / C

C=51 +52+~+54

_ (Lj
4 1)
5i -exp
Q. .~ Q.
!

or

}

(a)

=1 J

, .. :I.
,d';,'·'"C\ .,~·f '., '''' . i, ',,.." . ,~' :~~!i~~~

x
(a)

4"

=
, ;;,
(b)

Fig. 1. Position calculated from (a) or (b) for 14N particle.
Inner squares denote the boundary of the sensitive area.
In (a), the parameter P is set to be 13.78; in (b), theparameter n is 0.545. The shaping time constant is 3 J.Ls.

M. Ogiwara, et at.

175

2

Si= Qi ~ ;'(b)where p and n are parameters.
In derivation of these formulas, we assumed
that the charge Q collected on each electrodedepends on the distance, d, between the incident
position and the electrode. When the reflection ofa charge wave at the side of the detector is taken
into account, the dependence of Q on d is wellsimulated by (a) Q-:=:.::;p' /log(d / a), or (b) Q-:=:.::;d- n •In Fig. 1, examples of the position data areshown for the cases (a) and (b). In both cases,
position images are fairly well reproduced
except for those near the corners. Note that theposition linearity is still good at the side of thesensitive area, which is an important region forthe correlation experiments. The position resolution is as small as the collimator hole size at thecenter position, but becomes large for the position near the corner. It also depends on T andbecomes better for smaller shaping time constants.
References
1) T. Motobayashi, S. Satoh, H. Murakami, H. Sakai,and M. Ishihara: RIKEN Aeee!. Prog. Rep., 20, 125(1986) .

2) T. Kohno, et at.: RIKEN Aeee!. Prog. Rep., 21, 152(1987) .

176

RIKEN Accel. Prog. Rep. 22 (1988)

111-5-18.

Resonance Ionization Spectroscopy of a Fe Atomic Beam
Generated by a Spark Discharge Method
M. Otsuki,* T. Minowa, H. Katsuragawa, and T. Inamura

Figure 1 shows a photograph of the device for
production of a Fe atomic beam. Spark discharge
was produced by contact of a steel rotor (A) anda steel wire (B). The rotor was driven by a dc
motor (C). The wire was forced to touch the rotor
by using a magnetic coil (D) switching of which
was controlled by a computer. The repetition
rate of contact was set at 4 Hz. The rotor and thewire were connected to the positive and thenegative poles of a charged capacitor (1,500 J.l F,
15 V). We employed a rotation mechanism
because a rotating metal hardly welded withanother piece of metal in contact.
Spark discharge was efficiently produced in ahigh vacuum (10- 6 Torr) chamber. It is wellknown that discharge hardly occurs at such lowpressures. The reason why spark discharge occurred so efficiently is as follows: In the first

For resonance ionization spectroscopy (RIS), a
powerful tool is urgently required for generationof neutral atoms. We have reported RIS of atoms
generated by a laser ablation method. I) Although
the laser ablation method is one of the mostpowerful tools for generation of neutral atoms,
this method has some demerit: A difficulty in finecontrol of the generation rate of atoms and finedust creation which reduces sensitivity.
For metals a spark discharge method is better
substitution for the laser ablation method
because of its simplicity and low cost. Prior toapplying the spark dischasrge method to an
atomic beam source, we have carried out RIS of
Al and Fe atoms generated by the spark discharge method in order to investigate generation
rate. 2 ) In the present study, we have found muchless fine-dust creation, which improved the detection sensitivity of the apparatus. As a next step,
we have applied the method to a Fe atomic beamsource.

2(A)tl

384 nm i '----------~~.~"--------~

o
E-<

H

Z

::>

~

10

f-

386 nm

P'.

.x:

(B)

><
E-<

H
Ul

Z

~

E-<
Z
H

...:l

.x:
z

t.!l

H
U)

Fig. 1. A device for generation of an Fe atomic
beam by a spark discharge method. (A), (B), (C),and (D) denote a steel rotor, a steel wire, a dc
motor, and a magnetic coil, respectively.
• Department of Physics, Faculty of Science, Toho
University.

0f-t 'li I ~- I
.J

M. Otsuki, et al.

contact of the two metals they melt and vaporize
due to joule heating caused by a high peak current through the contact point. The vapor
becomes a seed for a spark discharge. The ionsand electrons produced by the spark discharge
increase the temperature of the metal surface togenerate further vapor. The ions and electrons
emit light by recombination, which is clearlyseen.
Except for the device for spark discharge, theexeperimental setup ,was the same as that described in Ref. 1. The neutral atoms existed only
during a few milliseconds after the discharges, sothat we optimized the delay time for triggeringof a pulsed laser and kept it under a computer
control. The ions and electrons generated by theresonance ionization were detected by two CERA TRON detectors, and recorded as a time-offlight (TOF) spectrum. In Fig. 2 an example of a
TOF spectrum of Fe ions is shown: (B) the pulsed
dye laser was tuned to the a 5D4 - z5D 4 transition of
Fe (386.0 nm); (A) and (C) the laser was detunedby 2 nm.
The observed TOF (about 2 j1s) was close to a
calculated value and the intensity of the peak
become most intense under the resonance condition. Therefore we were convinced that the peakin Fig. 2 was due to Fe ions caused by resonanceionization.
The total count of Fe ions in the TOF spectrum was about 30. The time to observe thespectrum was 220 s. The repetition rate of thepulsed dye laser was 4 Hz. Therefore the counting rate for Fe ions was 3 x 10- 2 per laser shot.

177

The volume of the ionization region was estimated at 10- 4 cm- 3 • If all Fe atoms in the ionization region were ionized and detected, the densityof the Fe atomic beam in the region was 3 X 10 2
cm- 3 • The solid angle of the ionization area
looked from the spark discharge was about 10- 7
sr. Thus a generation rate of 3 X 10 9 per discharge
was obtained; in this case the shorter duration
time of the laser pulse (10 ns) than that of thedischarge (longer than microsecond) was nottaken into account. We concluded, therefore, that
more than 3 x 10 9 atoms were generated at every
discharge. Emission of Fe atoms by heating due
to spark discharge lasted during about few
milliseconds. Hence the generation rate of 10 12 /s
was obtained. By thermal heating, the generation
rate of Fe atoms can be obtained at a temperature slightly about the melting point of Fe (1,800
K). The apparatus for spark discharge is much
simpler than that for heating thermaly to such ahigh temperature and is able to vaporize eventungsten (melting point 3,300 K).
In the present study we have demonstrated theusefulness of the spark discharge method as aneutral atomic beam source. For RIS of metal
samples this method will be most advantageousfor its simplicity and low cost.
References
1) T. Minowa, H. Katsuragawa, and M. Shimazu:
RIKEN Acce!. Prog. Rep., 21, 178 (1987).
2) T. Hoshino, M. Otsuki, T. Minowa, H. Katsuragawa,and T. Inamura: This Report, p. 178.

178'
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-19.

Resonance Ionization Spectroscopy of Neutral Atoms
Generated by a Spark Discharge Method

T. Hoshino,* M. Otsuki,** T. Minowa, H. Katsuragawa, and T. Inamura
We reported resonance ionization spectroscopy (RIS) of neutral atoms generated by a laser
ablation method.l} The laser ablation method is
one of the most powerful tool for generation ofneutral atoms because it is capable of vaporizing
all the matter. This method is based on highly
nonlinear phenomena caused by an intenseelectro-magnetic field, so that the fine control ofthe phenomena is difficult. This may lead to alow signal-to-noise ratio because the generationof neutral atoms by the method shows higher
order dependence upon the field intensity.
Another disadvantage of the method is that a lotof fine dust is produced because the laser ablation is essentially a micro-size explosion. The
dust scatters light, which causes the emission ofphotoelectrons and reduce signal-to-noise ratios,and pollutes a detector to reduce its sensitivity.
For metals a spark discharge method is abetter substitution for the laser ablation method
because of its simplicity and low cost. We successfully carried out RIS of Fe and Al atoms
generated by the spark discharge method andchecked the generation of much less fine dust
than in the laser ablation method, thus having
improved sensitivity.
The schematic diagram of the experimental
setup is shown in Fig. 1. Spark discharges were

performed by contact of a pair of metals connected to the plus and the negative poles of acharged capacitor (capacitance 4,500 ,uF andapplied voltage 10 V), respectively. The contact
was mechanically done between a star-shaped
plate rotated by a motor and a strip of the same
metal (5 cm long and 1 cm wide); the repetition
rate was about 2 Hz.
Resonance ionization of neutral atoms wereallowed to take place in a proportional counterby focusing radiation from a resonant pulsed dyelaser. Ionization signals were detected by astainless-steel wire biased at 1 k V and by using
the multiplying action of argon.
The discharge chamber was spatially separated from the proportional counter by connectingwith a Teflon tube, into which argon was supplied to transport neutral atoms generated in the
discharge chamber to the proportional chamber.
The flux of argon gas was about 10 cm 3 / s.
Because argon gas contained a small amount ofoxygen, the number of neutral atoms decreased
due to oxidation. The density of the neutral
atoms at the ionization region could, therefore,
be controlled by the flux of argon gas.
Except for the discharge method, the experimental setup was similar to that described in Ref.

x10 3

5

~ 4

H
til
Ar GAS

Z

~ 3

zH

H

2

I

1<1!

Z
l!l 1

Fig. 1.

Block diagram of the experimental setup.

* Department of Applied Physics, School of Scienceand Engineering, Waseda University.
** Department of Physics, Faculty of Science, Toho
University.

H
til

o
394
390
WAVELENGTH (nm)398

Fig. 2. A resonance ionization spectrum observedfor AI. The signal intensity is shown in electron
number generated by resonance ionization.

T. Hoshino, et al.

1. Ionization signals were amplified, averaged by
a boxcar integrator, and recorded against the
wavelength of the radiation from the pulsed dyelaser.
Spectra observed were shown in Fig. 2. The
peak I and II are due to resonance of the radiation from the pulsed dye laser with the 4S 1/2 3P3!2and the 4S1/23P 1/ 2 transition, respectively. We
measured the multiplying gain of the proportional counter by detecting a rays (241 Am) and yrays (55Fe). According to the measurement thesignal intensity corresponding to 2 X 103 e1ec-

179

trons that exist before electron-multiplication isindicated by an arrow. We succeeded in observing the spectra of Al whose peak intensity corresponds to 2 X 10 2 electrons. This sensitivity ismuch better than that achieved by the laser
ablation method. The discharge method can beapplied to all metals with high conductivities.
Reference
1) M. Otsuki, T . Minowa, H. Katsuragawa, M. Shimazu,and T. Inamura: RIKEN Accel. Prog. Rep., 21, 176(1987) .

180
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-20.

Resonance Ionization Spectroscopy with a Sputtering
Atomic Beam Source
M. Koizumi, T. Inamura, Y. Matsumoto, T. Murayama,
M. Takami, H. Katsuragawa, and I. Sugai

Resonance ionization spectroscopy (RIS)
makes it possible to detect a single atom withhigh selectivity of elements. I) Here we describe
the performance of a detector system for the RIS
chamber equipped with an ion gun to produce
neutral atoms. 2) Although the sputtering of atoms
with an ion gun is powerful especially for refractory elements, it is absolutely necessary to
remove stray ions and electrons produced by
sputtering ions in measurements of resonanceionization.
In order to remove these background ions andelectrons, wire meshes were placed between two
pin holes as shown in Fig. 1. Pairs of ion andelectron produced by the resonance ionizationof neutral atoms are detected with a pair ofceratrons. An electric field between the two
ceratrons drives ions and electrons oppositely tothe detectors. The electrons give prompt signals
and the time difference between collected ionsand electrons depends on the mass of ions, theelectric field, and the distance between thedetectors.3)
atomic beams

laser beams

First, we carried out a test experiment on
sodium atoms with a thermal atomic beamsource, which were resonantly ionized via thetransition'Ut

where VI and V2 correspond to wavelengths Al =589.5930 nm and A2=568.267 nm, respectively.4) A
first photon tuned to Al (laser 1) was obtained
from a cw-dye laser pumped by an Ar-ion laser,
and a second photon tuned to A2 (laser 2) from apulsed dye-laser pumped by a copper-vapor laser.
The two photon beams crossed the atomic beams
at right angles. Laser 1 with a power of about 1.4mW was focused on a 2-mm diameter spot in
sodium beams; and laser 2 with a 6-kHz repetition rate and a 20-ns pulse width on about 1 mm
in diameter in the interaction region at a powerof about 35 m W. The distance and potential
difference between two ceratrons was 40 mm and4.5 kV, respectively.
A time spectrum observed with a time-toamplitude converter is shown in Fig. 2. There are
two peaks: The left-hand-side peak is a prompt
peak due to the background signals; the righthand-side one is a delayed peak produced byresonantly ionized sodium atoms (23Na+). The
distance between the left- and right-hand-side
peaks is about 346 ns, which is nearly equal tothe value estimated by taking into account acone shape of the ceratron like a trumpet's headwith a depth of about 10 mm. The time resolution
258

C
0

u

N
T

Fig. 1. Schematic diagram of resonance ionization
spectroscopy with a sputtering atomic beamsource.

'Ut, lJ.!

lJ.!

32S1!2~32PI 12 ~42D3/2 ~ Na ++ e-

r

~

{{

3M

..::l

",

£

Q
FWHM
26.2nsCHANNEL

Fig. 2. Time-of-flight spectrum of resonantly ionized N a atoms.

M. Koizumi, et al.

(FWHM) observed was 26.2 ns.
Measurement with the Ar-ion gun is in progress on Na atoms for reference, and we proceed
to investigate refractory elements such as Mo,
Hf, Os, Ta, and W by the method of Ar-ion beam
sputtering.
References
1) V.S. Letokhov: Laser Photoionization Spectroscopy,

181

Academic Press, Orlando (1987).
2) T . Murayama, M. Takami, Y. Matsumoto, and T.
Inamura: RIKEN Accel. Prog. Rep., 21, 174 (1987) .
3) T . Minowa, H. Katsuragawa, K. Nishiyama, T.
Inamura, and M. Shimazu: ]. Appl. Phys., 61, 436(1987) .
4) S. Mayo, T .E. Lucatorto, and G.G. Luther: Anal.
Chern. , 54, 553 (1982).

182
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-21. A Radiation-Detected Optical Pumping System
for the Achievement of Nuclear Orientation in Solids
S. Matsuki, K. Shimomura, M. Koizumi, T. Murayama, and T. Inamura

Oriented samples of nuclei are of considerable
utility in solid-state, nuclear, and particle
physics. Especially in nuclear physics, theachievement of significant nuclear orientation is
crucial for the precise measurement of nuclear
magnetic and quadrupole moments of unstable
nuclei. Among various methods in use for orienting nuclei, optical pumping is a relatively simple
and still quite efficient method for getting significant nuclear orientation. The developement of atechnique for orienting nuclei in solids by opticalpumping is highly desirable, since the method
does not require either sub-Kelvin temperatureor high magnetic field as opposed to the case ofthermal equilibration methods.
We have developed a new technique for orienting unstable nuclei with the optical pumping insolids and for detecting the degree of orientation
by a sensitive measurement of the ,B-decay asymmetry and/or the y-rays anisotropy from oriented nuclei (,B( y)-RADOPS; ,B-rays (y-rays)
Radiation-Detected Optical Pumping in Solids).
With this technique, we achieved nuclear polarization of up to about 4% in SrFz crystal.!)In order to apply the method further to thestudy of nuclei far from the stability line, we now
are developing an experimental system for the,B( y)-RADOPS system at RIKEN. The apparatus

system is schematically shown in Fig. l. The
unstable nuclei produced in heavy-ion reactions
are mass-separated with the isotope separator
GARIS-IGISOL system, or the recoil-ion separator RIPS system in RIKEN Ring Cyclotron facility, and are then implanted into a sample crystal,such as CaF 2 and GaAIAs which is cooled down
to 77 K to l. 7 K in a cryostat. The implanted
atoms are then optically pumped with a circularly polarized laser beam at an appropriate wavelength, thus achieving nuclear as well as electron
orientations. The degree of nuclear orientations
is measured by detecting the asymmetry of emitted ,B rays and/or the anisotropy of emitted yrays in the angular distributions following the
decay of the unstable nucleus.
The experimental setup of the detecting system is schematically shown in Fig. 2. The f3 rays
are detected with a counter telescope of plastic

tiq.N

Z

Radiation
ShieldLaser~~GlassJ

Light guide

window

Scintillato

SCintillator

Scintillator---78

VacuumRF~r______~11 1IIIr_______-~~~

Fig. 1. Schematic diagram of the present experimental ,B(y)-RADOPS system for the achievement of
nuclear orientations.

Fig. 2. Schematic detail of the detecting system of
the present ,B(y)-RADOPS experiments. An RF
system is applied to measure radiation-detectedmagnetic resonance for the precise measurement ofmagnetic moments.

S. Matsuki, et al.

Fig. 3. Schematic structure of the liquid He cryostat
system in the present ,B(y)-RADOPS experiments.

183

ber with Ge(Li) detectors. An electromagnet witha variable pole gap, into which a liquid He
cryostat system is inserted, produces a magnetic
field of up to 3.0 kG at a gap width of 15 cm. The
magnetic field is uniform to less than 1 Gat 3 kG
within the area of 1 cm 3 at the center of the polegap.
The liquid-He cryostat system is shown in Fig.
3. About 15 I of liquid He can be contained in thecryostat, thus enabling to maintain sample crystal at low temperature for more than 20 hours
even under laser irradiation for optical pumping.
This system can be utilized for both off-line
and on-line experiments. A few unstable nuclei
with lifetimes longer than 1 day will be firstly
investigated off-line, then the on-line research oflight nuclei with shorter lifetime will befollowed.
Referencescintillators and/ or a solid-state counter systemin the sample chamber set parallel to the laser
beam. The y rays are detected outside the cham-

1) K. Shimomura, S. Matsuki, S. Uemura, T. Kohmoto,Y. Fukuda, and T. Hashi: Proc. lnt. Conf. Quantum
Electronics, Tokyo, Jul., p. 298 (1988) .

184
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-22.

An Attempt for a Local Loop Network Using an MC6854 ADLC

J. Fujita
RIKEN Ring Cyclotron is a computer
controlled accelerator. I) A CIM-DIM microcomputer network 2 ) interfaces between the computer
system and electric instruments and machines
along the accelerator. A CIM module is connected to max. 12 DIMs in a star configuration.
This type of network has a disadvantage ofcomplication and overlapping of network wirings. A loop configuration gets rid of the annoyance and expands the number of nodes.

r

OOPl
Rx

Down
loop

Tx

MPU

ADLC

Ea300

68854

RAM

DMAC

(8K8)

68844

I

Primary Station
Loop
Controller(Non-Loop)

PFOvt

PIA

(4K8)

68821

I
ACIA

-

Portable

Console68B50

Fig. 2. Block diagram of the station.
Secondary
StationSecondary
StationFig. 1. Loop configuration.

The loop configuration we studied is composedof three stations, a primary station and two
secondary stations as shown in Fig. 1. Threestations have the same circuit arrangement
shown in Fig. 2 except for a switching circuit ofa synchronous clock in the primary and repeater
logics in each secondary. Three chips form thecore of the loop network function. A microprocessor MC68BOO is chosen because of its
availability of hardware and software, and pincompatibility with other two chips. An Advanced
Data Link Controller (ADLC), MC68B54, provides data link capability. Incorporation of a
Direct Memory Access Controller (DMAC),
MC68B44, with ADLC allows to transfer large
data with high speed on the loop. The loop isalways under control of the primary. The ADLC
in the primary operates in a non-loop full-duplex
mode. The ADLCs in the secodaries operate in aloop mode, monitoring up-loop data on theirreceiver data input. The ADLC transmits andreceives bit-oriented data in a format called aframe. All frames start with an opening flag andend with a closing flag. Between both flags, aframe contains an address field, a control field,
an information field and a frame check sequence(FCS) field. The primary station provides serial
data and a synchronous clock to the receiversection of the secondaries through two twisted
pair cables. Each secondary is in sereis and adds
one bit delay to the loop data.
The loop is set to a mark idling state by initialization of the system. The synchronous clock
rate in the state is 230 kbps. The primary sends a
message of length of three bytes on the loop. The
first byte is an address of a delivered secondary
station and permits up to 256 different addresses.
The second is a command or a response to thesecondary. The last shows the length of the data
record. When the secondaries receive the frame,
they interrupt present work and compare thereceived address with their own. The stations ofa different address return to a paused sequence.
The fitted station decodes the next control field
and answers to the primary with an "Acknowledge" frame. It has the length of three bytes inthe same format as the message from the pri-J. Fujita
mary. If the content of the control field includes
transfer of block data, the two stations change
the state to a DMA mode and the synchronous
clock is accelerated to 1.84 Mbps by the primary.
That is, in a DMA mode, data are transferred at
a rate eight times faster than 0.23 Mbps in theidling state. At the end of DMA transfer, theprimary sets the clock to be a slow rate again
and the loop network comes back to the idlingstate. A programmable frequency divider IC
SN74LS292 on the primary board serves toswitch the clock. The IC divides 7.37 MHz quarz
controlled oscillating frequency to 1/4 or 1/ 32.
The clock rate of the microprocessor is 1.84
MHz, which is the same rate as a synchronous
clock at a DMA mode. The ADLC has 32-bit shift
registers in RxD input and TxD output to relieve
some of software constraints. Exchange of the
3-byte message in an idling state is based on thefeature. The message over 3-byte tends to generate an error of receiver overrun in the present
system.
A gate logic on the secondary board repeats
up-loop data to down-loop station as shown in
Fig. 3. If a Loop On-line Control (LOC) signal of
ADLC holds a high level, up-loop data moves
down-loop via gate A. The station gets out theloop. If the LOC is low, up-loop data moves

185~ - --- - ---- - --------------- -

RxC
TxC

1-----....-< t--~-....l...-"'" elK in
I»------'_ CLK out

AOLC

RxO r---:-----jp--~,..___,.--_+_....... Up-Loop Oata
LOCt--~----{

TxO . - - " 7 - - - - - - 1

I

Gate B

Oown-Loo/=:- _ _ - - - - - - - - - - __ - _ . . . __ - - _ .. _ I

Fig. 3. Repeater logic.

down-loop via an ADLC receiver-transmitterplus gate B. The station gets in the loop. The
synchronous clock moves down-loop with thesame phase through two inverters.
Short twisted pair cables are used to connect
the stations in the test system; communication
between remote stations is feasible by replacingof the cables with optical fibers and by changing
I/O parts.
References
1) T. Wada, H. Takebe, J. Fujita, T. Kanbara, and H.

Kamitsubo: RIKEN Aeee!. Prog. Rep., 20, 170 (1986).
2) N. Nagase, H. Takebe, T . Wada, and K. Shimizu:
11th lnt. Conf. Cyclotron and Their Applications,Tokyo, Oct. (1986) .

186
RIKEN Accel. Prog. Rep. 22 (1988)

111-5-23.

Spectral Analysis with a Graphic Terminal
M. Yasue and T. Wada

A program which was originally coded by T.
Wada was modified so that one can handle spectral data displayed on graphic terminal by
conversing with a super-mini computer S-3500
through a keyboard or a touch-pen. Also improved were several points such as 1) easiness ofhanding, 2) analysis speed, 3) versaltile curves
for a continuum background in spectra and, 4)availability of spectral data with several types of8, 16, 20, 24, and 32 bits/channel. Instructions to
use the program are descrided in Ref. 1.

With the aid of a peak fitting procedure, thecross sections for high-spin states lying above thethresholds of particle decay can be obtained,
providing interesting shell structures of the unbound high-spin states in light nuclei. 2 •3 )References
1) M. Yasue and T. Wada: INS·Rep., No. 670, 1 (1988).
2) R.]. Peterson, et at.: Phys. Rev. C, 38, 1130 (1988).
3) M. Yasue, et at.: to be published in Phys. Rev. C.

187
RIKEN Accel. Prog. Rep. 22 (1988)

IV.

NUCLEAR DATA
1.

Status Report of the Nuclear Data GroupA. Hashizume, Y. Tendow, Y. Ohkubo, K. Kitao, and K. Sueki
In this period four items have been continued
as the last work.I} They are (1) the compilation of
charged particle induced reaction cross section
data,2) (2) the evaluation of cross section data forcharged particle induced reactions, (3) the masschain evaluation of nuclear structure data, and(4) the compilation of the nuclear references
taken from the reports published in Japan. For
the first item, we cooperated with Nuclear Data
Section in International Atomic Energy Agency(IAEA) and other nuclear data centers. The
second was started from the recommendation of
the IAEA meeting held in Tokyo in 1987. 3) The
third is concerned with the world wide masschain evaluation work of nuclear structure forthe implement of the Evaluated Nuclear Structure Data File (ENSDF). We cooperated with anuclear data group in Japan Atomic Energy
Research Institute. The fourth is connected to
the RNDF (References of the Nuclear Data
File). NNDC (National Nuclear Data Center) in
Brookhaven National Laboratory compiles thereferences and publishes as The Recent References for nuclear structures and reactions. We
owe the covering the reports published in Japan.
(1) The work for the compilation of new
EXFOR (Exchange Format for Experimental
Data) files of nuclear reaction cross sections has
been continued. The reactions in which we mainly interested are those whose products are utilized for mediobiological applications. The crosssections of the reactions producing the following
isotopes have been compiled in the EXFOR file.
The isotopes are llC, 13N, 150, 18F, 28Mg, 52Fe,
67Ga, 68Ge, 68Ga,?4As, 77Br, 82Br, 77Kr, 81Rb, 82mRb,
III In, 123Xe, 127Xe, 123 1, 124 1, and 1251 nuclei. 1) We
have also compiled the reaction cross-sections
for various combinations of incident particles
and target nuclei described in the reports inwhich the above primarily interested reactions
were investigated. The effort was made in thisperiod to complete the collection of these data
and to make figures of cross section data for
publication, and the situation of cross sections

producting positron emitters lIC, 13N, 150, and 18F
were studied. 4- 6)
The number and kind of nuclides for medical
use are increasing; there are 65 radioisotopes
permitted legally for pharmaceutical applications. However more than 50 nuclides are also
proposed for medical use and the production
methods have been studied.
The compilation of the integrated nuclear
reaction cross-section data originated in Japan in
the EXFOR files is continued. The main sourcesof recent data are annual reports published byuniversities and institutes having accelerator
facilities.
(2) As explained in the last status report,?) it
is important to make clear the present status andto propose standard cross sections for monitor
reactions. We are examining the details of collected data on the 12C (p, pn) l1C, 27 Al (p, 2pn) 24Na,
63CU (p, 2n) 62Zn , and 65CU (p, n) 65Z n reactions.
A new version of a computer code ALICE tosearch parameters and to calculate nuclear reaction cross sections in compound and precompound processes is being used. By using this code,
the comparison between the experimental results
and the those from the exciton model can be
made. The parameter search of the code wascarried out for the several reactions. The center
host computer used for the calculation is aF ACOM 780/ 10.
(3) For the mass chain evaluation of nuclear
structure data, a new editor for treating thenuclear structure data file was completed for acomputer PC-9801. The evaluation work on the
nuclear structure of the A = 177 mass chain has
been continued.
(4) The recent reference files published periodically by Brookhaven National Laboratory
should cover all references in the field of nuclear
physics. The references of annual reports andquartary reports published in Japan werecompiled and preparing to sent to the BNL Data
Center. In connection with this work, all reference files of Nuclear Data Sheets were received.

188

A. Hashizume, et al.

References
1) A. Hashizume, Y. Tendow, Y. Ohkubo, K. Sueki, K.
Kitao, and T. Nozaki: RIKEN Aeee!. Prog. Rep., 20,
152 (1986).
2) A. Hashizume: Invited talk and Proc. Int. Conf.
Nuclear Data for Science and Technology, Mito,
May (1988).
3) Report on the 8th IAEA Consultants Meeting of the
Nuclear Reaction Data Centers, INDC(NDS) ·178.
Oct. (1985) .

4) Y. Ohkubo, A. Hashizume, Y. Tendow, and K. Kitao:
This Report, p. 189.
5) A. Hashizume,Y. Ohkubo, Y. Tendow, and K. Kitao:
This Report, p. 19l.
6) Y. Tendow, A. Hashizume, Y. Ohkubo, and K. Kitao:
This Report, p. 194.
7) A. Hashizume, Y. Tendow, Y. Ohkubo, K. Kitao, K.
Sueki, and T . Nozaki: RIKEN Aeee!. Prog. Rep., 21,
185 (1987).

189
RIKEN Accel. Prog. Rep. 22 (1988)

On the Cross Sections for the 1 2 C (p, pn) l1C Reaction

IV-2.

Y. Ohkubo, A. Hashizume, Y. Tendow, and K. Kitao

A single nucleon removal reaction is an
important reaction for studies of both nuclear
Table 1.

structure and reaction mechanism itself. The
12C (x, xn) lIC reaction was studied for the above

List of the total cross sections for the 12C (p, pn) llC reaction.

First author

Place

Ref.

Target(mg/ cm 2)*

Beam energy(MeV)··

Detector

RL. Aamodt(Berkeley)1)

340,32GM

stacked foils at 340 MeV

J.M. Cassels(Harwell)

2)

142(Harvard)

3)

100

internal,
NaI
GM

5%, ionization chamber

N .M. Hintz

5-mil,
O. 010-in.
polystyrene
1,750,
naphthalene
0.005-in.
polystyrene

W.E.
CrandallA.H.
Rosenfeld
Iu.D.
Prokoshkin(Berkeley)4)170-350

ppc(Chicago)

5)

461

ppc

(USSR)

6)

1- 15 milpolystyrene4,polyethylene
graphite

150-660

ppc

J.B.

(Brookhaven)7)

Cumming

NaI

5%3, plastic
3, 4.5, 6 Ge V
scinto10) 540, graphite 383

internal

5.4% at 3 GeV, 6.1% at 4.5 GeV, 5.4% at
6 GeV, emulsion
2.9-3.6%, beam energy degrader covering
energy range down to 288 MeV, Faraday
cup
5.0%, 20-plate secondary emission chamber
4.6%, 4 types of combination with emulsions and plastic scint.

8)(Berkeley)

9)V. Parikh(Liverpool)

K. Goebel(CERN)

J.B.

(Brookhaven)

J.B.

(Brookhaven)

D.F.
Measday
P.T.
Andrews(Harvard)

K.R
Hogstrom
S.B.
Kaufman(Los
Alamos)(Argonne)(Liverpool)

2- 4%, thermal battery, normalized relative cross sections to the value of Ref. 4
at 350 MeV
3.5% at 2 GeV, 3.8% at 3 GeV 3-element
scint. counter telescopeinternal(McGill)Cumming

stacked foils, energy range from threshold to 100 Me V, normalized the relative
excitation function to the absolute valuesof Ref. 1 at 32 and 110 MeV+5, - 4% at 350 MeV, stacked foils, beamenergy degrader, Faraday cup
3%, ionization chamber

I-in.
2,3 GeVpolystyrenebased plastic
scint.
10,polythene 42

A.B.
Whitehead
N. Horwitz

Cumming

Errors and commentGM11) 300,
591
polythene12) I-in.
28 GeV
polystyrenebased plastic
scint.
13) 10,51
polytheneGM14) 1.4-mm
polystyrene15) 50, 250, 375,
and 625,
polystyrene16) 181 and 354,
plastic scinto17) 310, plastic
scinto

160

NaI

385

internal,
NaI

800

internal,
NaI
internal,
NaI

300 GeV• If unit is not given, thickness is represented by mg/cm 2.
** If unit is not given, beam energy is represented by MeV.

internal

NaI

3.0-3.4%, stacked foils with beam energy
degrader covering energy range down to
21 MeV, Faraday cup
2.9- 3.5%, beam energy degrader covering
energy down to 51 MeV, Faraday cup
1.6%, Faraday cup
3.1% based solely on the uncertainty inion chamber, ion chamber
6.5%, scint. counter telescope

Y. Ohkubo, et at.

190

purposes and also for monitoring beam intensities because of the convenience of measuringllC activities. The cross sections of the 12 C (p,pn) llC reaction were measured in the energy
range from threshold (18.5 MeV) to 300 Ge V bynumerous investigators. Listed in Table 1 arerepresentative authors who measured cross sec-

tions of this reaction, target thicknesses, primarybeam energies, detector employed, errors,
methods for beam intensity determination and soon. Table 1 does not include all the data
published on the reaction. The data of several
experiments up to 300 Ge V of incident energies
are plotted in Fig. 1.

.

100

90

80
70

60

:0

50

E

'0

40

30
20

10
0
10 MeV

100 MeV

1 GeV

10 GeV

100 GeV

1 TeV

E(p}

Fig. 1. Excitation function for the 1 2 C(p, pn) IIC reaction.

The results of Aamodt, et at. I) were shown to
be in error owing to absorber effects,4) counter
efficiency 5) and gas loss from thin plastic target
foils. 18•19 ) The value at 385 MeV of Andrews,
et at. 15 ) is greater than the value measured by
Parikh. IO ) Andrews, et at. made a comment thatthe uniformity of graphite targets employed by
Parikh and the difficulties associated with thecalibrated Geiger counter technique could have
led to errors of the magnitude of Parikh.
References
1) RL. Aamodt,V. Peterson, and R Phillips: Phys. Rev.,88, 739 (1952).
2) ].M. Cassels, T.G. PiCkavance, and G.H. Stafford:
Proc. Phys. Soc. A, 214, 262 (1952).
3) N.M. Hintz and N.F. Ramsey: Phys. Rev., 88, 19(1952) .
4) W.E. Crandall, G.P. Millburn, RV. Pyle, and W.
Birnbaum: Phys. Rev., 101, 329 (1956).
5) A.H. Rosenfeld, RA. Swanson, and S.D. Warshaw:
Phys. R ev., 103, 413 (1956).
6) Iu.D. Prokoshkin and A.A. Tiapkin: JETP (Sov.

Phys.) , 5, 148 (1957).
7) ].B. Cumming, G. Friedlander, and C.E. Swartz: Phys.
Rev., 111, 1386 (1958).
8) A.B. Whitehead and ].S. Foster: Can. ]. Phys., 36,
1276 (1958).
9) N. Horwitz and ].]. Murray: Phys. R ev., 117, 1361
(1960) .
10) V. Parikh: Nucl. Phys., 18, 628 (1960).
ll) K. Goebel, D. Harting, ].c. Kluyver, A. Kusumegi,
and H. Schultes: Nucl. Phys., 24, 28 (1961).
12) J.B. Cumming, G. Friedlander, and S. Katcoff: Phys.
R ev., 125, 2078 (1962).
13) J.B. Cumming: Nucl. Phys., 49, 417 (1963).
14) D.F. Measday: Nucl. Phys., 78, 476 (1966).
15) P.T. Andrews, P.G. Butler, A. Christy, A.N. James, P.
Kirkby, B.G. Lowe, and B.W. Renwick: Nucl. Phys.,AI09, 689 (1968).
16) K.R Hogstrom: Phys. Rev. C, 14, 753 (1976).
17) S.B. Kaufman, M.W. Weisfield, B.D. Wilkins, D.
Henderson, and E.P. Steinberg: Phys. Rev. C, 13,253(1976) .
18) H. Fuchs and K. Linderberger: Nucl. Instrum.
Methods, 7, 219 (1960).
19) J.B. Cumming, G. Friedlander, J. Hudis, and A.M.
Poskanzer: Phys. Rev. Lett., 6, 484 (1961).

191
RIKEN Accel. Prog. Rep. 22 (1988)

IV-3.

The Nuclear Data for 13N Production

A. Hashizume, Y. Ohkubo, Y. Tendow, and K. Kitao

Nitrogen-13 is used in the studies on metabolic
fate of nitrogen-containing biomolecules in biological systems at tracer levels with an extremely high sensitivity. The 160 (p,a) 13N reaction iscommonly employed to produce a radiomedical
nuclei 13N. Gas targets can be cryogenicallytransferred to a vial containing activated charcoal. Other reaction cross sections studied bylight incident particles are listed in Table l.
Besides the reaction listed in Table 1, the neutron
stripping reactions induced by heavy-ion 14N
have been studied for ten kinds of targets. I - 3)
Excitation functions of the 12C(p, y) 13N,4,S)
13C(p, n) 13N,6) 14N (p, pn) 13N/) 12C(d, n) 13N,S) and13C (3He, pn) 13N9) are shown in Figs. 1, 2, 3, 4, and5. For (p, y) reaction cross sections, Ha1l 4) and
LambS) studied in a high energy region and
Cohen 10) for incident energies of 5 and 11 MeV.
As shown in these figures, the resonance is observed in (p, n) and (d, n) reactions. In obtaining
their cross sections, neutrons were directly measured. The target thickness of the 13C in (p, n)reaction was 24.8 Jig/ cm 2 and those of 12C in (d,n) reaction were 80 and 92 Jig/cm 2. Incident
Table 1.

protons or deutrons were accelerated with a Van
de Graaff generator. The overall accuracy of thecross section values reported is within ±3 % for
the (d, n) reaction.
Figure 6 shows the excitation function of
160 (p, a) 13N. The cross sections were first reported by Whitehead and Foster l l ) followed by
Furukawa. 12 ) Hill 13) observed several resonancesfrom a high resolution measurement. McCamis,14)Vero,1S) Gruhle,16) and Sajjard 7) also studied thecross sections of 170 (p, a).
The excitation function reported by Gruhle(indicated by a line in Fig. 6) has statisticalerrors of about 2% in the high energy region andabout 15% in the low energy region. The absolute values have errors of about 9%. Nitrogen-13
could also be produced by (p, pt) or (p, dd)
reactions; however, these reactions have not yet
studied in a wide range of incident energies.
There is a report only at 50 MeV.l7)
The 160 (p, a) 13N reaction has also been subjected to the attention of astrophysists in connection with the oxygen burning in steller regions.

Reactions for 13N production by light particles.

Range of particle
energy (Me V)

Particle energy
at maximum crosssection (Me V)

Maximum crosssection

12C(p, y) 13N

5,11

5

2.5 mb12C (d, n) 13N
13C (p, n) 13N

80- 127
1.5- 4.5
3.2-5.3
4.5- 24

2.3
5
13

200
90
135

8)
6)
9)

12.6-29.8
6.8-17.8

20
8

32
120

7)
7), 11), 12), l3)14), 15), 16)
17)
17)

Reaction

13C (3He, pn) 13N +13C (SHe, d) 13N
14N (p, pn) 13N
160 (p, a) 13N
160 (p, pt) 13N
160 (p, dd) 13N5050

21 (at 50 Me V)
12 (at 50 Me V)

Reference4), 10)

192

A. Hashizume, et al.
10

1

1

I

1

1

t

' 1

++

t!

V1

C
L

0
.0

;::,

E

V1

c 100

I

I

tt ·
t·

'<5'

0

1

E ·~

1
90

W

1
1

I

1

(I:

11(':

ENERGY

12 S
I

0

0

0

l

3.0
140

I'"';"'l

0

0

0

0

0

0

1
5.0

4.0

6.0

ENERGY ( MeV)

MeV)

Fig. 1. Excitation function of l2C(p,y) l3N. From
Refs. 4 and 5. The results of calculation by using
Breit·Wigner's formula are cited in Ref. 5. These
values are plotted by black triangles in the figure.

o

,

10

t·
7e

'!¢O

0°0 0

T'

C. I

0

;",:00/

00

'E

-

f

0

a

-

"?"

f-

~~""

L

0
.0

Fig. 2. Excitation function of l3C (p,n) l3N. From
Ref. 6.

c

0

1

V1

c

?

L
0

.0

-

;:: 10!'" (/I'~'Yv-\/ 1

J

t
l-

E
Y 0

0

1 :)

:

1

'5

,·0

25

lo~l~I

3C; .0

ENERGY (MeV)

3.0

4. 0

ENER GY fMe))

Fig. 3. Excitation function of l4N (p,pn) l3N. From
Ref. 7.

Fig. 4. Excitation function of l2C (d,n) l3N. From
Ref. 81000 r-r-..--r--r-""-I"""""""''''-'I "'--'--'--.--r,---'--'--"',"""'''''''''''''''V1
C
L

z. . 0

100f-

0
.0

-

E
0

-

10 1-

..
I~~~~
I
~~~
I~~,~
I~~I~~~

o

10

15

20

E NER GY (MeV)

Fig. 5. Excitation function of l3C (SHe,From Ref. 9.

25

193

A. Hashizume, et al.
IOOO~~~~rrmmrrmmTImmrrmmmmTImmrrmmnrrmmmmnmmrrmmTIIT~mm~mrrmq

til

C 100

L

o

.D

C

L

t)

10

..
.

~,

6

8

10

12

14

16

ENERGY (MeV)

Fig. 6. Excitation function of 160(p,a) 13N. From Refs. 11, 12, 13, 14, 15, and 16.

References
1) M.L. Halbert, T.H. Handley, J.J. Pinajian, W.H.

Webb, and A. Zucker: Phys. Rev., 106, 251 (1957).
2) J.G. Couch and J.A. McIntyre: Phys. Rev., 152, 883(1966) .
R.M. Gaedke, K.S. Toth, and I.R. Williams: Phys.
Rev., 141, 996 (1966).
4) R.N. Hall and W.A. Fowler: Phys. Rev., 77, 197 (1950).
5) W.A.S. Lamb and R.E. Hester: Phys. Rev., 107, 550
3)(1957) .
6) J.H. Gibbons and R.L. Macklin: Phys. Rev., 114, 571(1959) .

7) M. Sajjad, RM. Lambrecht, and A.P. Wolf: Radiochem. Acta, 39, 165 (1986).
8) RJ. J aszczak, R.L. Macklin, and J .H. Gibbons: Phys.
Rev., 181, 1428 (1969).
9) D.RF. Cochran and J.D. Knight: Phys. Rev., 128, 1281
(1962) .

10) B.L. Cohen: Phys. Rev., 100, 206 (1955).
11) A.B. Whitehead and S. Foster: Can.]. Phys., 36, 1276
(1958) .
12) M. Furukawa, Y. Ishizaki, Y. Nakano, T. Nozaki,
Y. Saji, and S. Tanaka: ]. Phys. Soc. lpn., 15, 2167
(1960) .
13) H.A. Hill, E.L. Haas, and D.B. Knudsen: Phys. Rev.,
123, 1301 (1961).
14) R.H. McCamis, G.A. Moss, and J.M. Cameron: Can.
]. Phys., 51, 1689 (1973).
15) A.V. Vero and A.J. Howard: Nucl. Phys., A210, 60(1973) .
16) W. Gruhle and B. Kober: Nucl. Phys., A286, 523(1977) .
17) A.1. Vdovin, I.G. Golikov, M.N. Jikov, 1.1. Lojakov,
and V.1. Ostroumov: Izv. Akad. Nauk., 43, 148(1979) .

194
RIKEN Accel. Prog. Rep. 22 (1988)

Excitation Function Data for 150 Production

IV-4.

Y. Tendow, A. Hashizume, Y. Ohkubo, and K. Kitao

Radioisotope 150 is widely used in a variety of
applications. Because of its short halflife CTIJ2= 2.04 min) and pure {3+ emission CE = 1. 74
MeV), 150 is an especially suitable radiotracer
for life science and biomedical applications. 150
is also used for the activation analysis of nitrogen by the 14N Cd, n) 150 reaction. 150 isotope is
produced via several nuclear reactions. The excitation function data for these reactions arevery important to estimate the final yields of 150.
Nevertheless, only an insufficient number ofworks on the cross section measurements haveappeared in the literature. The possible reactions
to produce 150 isotope are 14N(d, n)150,
15N (p, n) 150, 160 (p, pn) 150, 14N (3He, d) 150 and
12C(a, n) 150.
Among these reactions, 14N (d,n) 150 seems to
be useful when high specific activity or carrierfree products are required. Wholleben andSchuster 2) measured the cross sections for deuterons of 0.5 and 3.2 MeV. They used a thick-target
yield method on boron nitride targets. Ruiz and
Wolfl) studied the reaction on nitrogen gas targets with deuterons of 0.6-14.35 MeV by using asaturation method. Excitation curves obtained in
the two studies show very similar shapes, but theabsolute values of Wholleben are systematically
1.4 times grater than those of Ruiz. The curves
are shown in Fig. 1 up to about 5.7 MeV. Ruiz's
data above that energy are not shown here in the
figure but they slowly decrease until up to 14.35
MeV. The cross sections published by Newson 4)
as early as in 1937 are an order of magnitude
lower than the data published there after. RetzSchmidt and Weil 3) measured the excitation function for the same reaction to the 150 ground state
only.
In the case of 15N (p,n) 150 reaction, it is necessary to employ an enriched 15N 2 gas target.
Barnett 7 ) measured the relative total cross section in the range of 3.78-12 MeV and the absolute
cross sections at 5.52, 5.68, and 5.75 MeV. The
excitation curve had many resonance peaks anda maximum of '""-'300 mb at around 6.4 MeV.
Sajjad, et al. 5 ) measured the cross section in therange of 3.72 - 16.58 MeV. The shape of their
excitation curve was very similar to Barnett's
but absolute values were systematically smaller.
Sajjad 5) asserted that the discrepancy might bedue to incorrect measurements of the absolutedetector efficiency in Barnett's work.?)
The cross sections for 160 (p, pn) 15 0 on beryl1000~-----~1-----~
1-----~
1----~_

-.•

:

0

0

o

0

000

0

0

0

0

0

0

100

..

.0

E
'-'

-

10 f-

-

•• 0

• •- 0

.0

0

'-'

••

100 f-

E

. rP'

-

tl

10

tl

.

I-

o

I-

1~~~~~~~~~~~~~~o2345
Energy(MeV)

67Fig. 1. Excitation curves for 14N (d, n) 15 0 by
o Ruizl) and. Wohlleben. 2 )

o

j

I

I

50

100

150

Energy(MeV)

200

Fig. 2. Excitation curve for 160 (p, pn) 150 by
Valentin. 8 )195

Y. Tendow, et al.

Table l. Excitation functions for ISO production.
Reaction

Energy (MeV)

14N (d, n)
14N (d, n)
15N (p, n)
15N (p, n)
15N (p, n)
16 0 (p, pn)
16 0 (3He, a)
12C (a, n)

0.6 - 14.35
0.5 - 3.2

220 (at 2.8)300 (at 2.8)

2)

3.72- 16.58

142 (at 6.41)

5)207 (at 6.31)
resonance peaks
70 (at 50)
169 (at 6.6)
resonance peaks

6)

5.53-

9.26
3.8 - 12-15530
2.9 - 8.9
11.35- 22.65

lium oxide targets were measured by Valentin 8 )for protons of 30-155 Me V, the exci ta tion curveis shown in Fig. 2.
Hahn, et ai. 9 ) measured the cross sections forthe 160 (3He,ll') reaction using Mylar-foil targets
at a beam energy range of 2.9 to 8.9 MeV. The
maximum value was 169 mb at 6.6 MeV beamenergy.
The cross sections for 12C(ll',n) 15 0 were measured by Black, et ai. 10 ) by using an activation
method from the threshold at 11.345 MeV up to
22.65 MeV. The excitation curve shows a complex resonance structure varying from 5 to 25
mb.
A breif summary for the cross section data
published to date are given in Table 1.

O"max(mb at Me V)

Reference
1)

7)
8)
9)
10)

References
1) H. Vera Ruiz and A.P. Wolf: Radiochim. Acta, 24, 65(1977) .
2) Von K. W ohlleben and E. Schuster: Radiochim. Acta,12, 75 (1969) .
3) T. Retz-Schmidt and ],L. Weil: Phys. Rev., 119, 1079
(1960) .
4) H.W. Newson: Phys. Rev., 51, 620 (1937).
5) M. Sajjad, RM. Lambrecht, and A.P. Wolf: Radiochim. Acta, 36, 159 (1984).
6) K. Murphy, RC. Byrd, P.P. Guss, c.E. Floyd, and
RL. Walter: Nuc!. Phys., A355, 1 (1981).
7) A.R Barnett: Nuc!. Phys., A120, 342 (1968).
8) L. Valentin: Nuc!. Phys., 62,81 (1965).
9) RK. Hahn and E. Ricci: Phys. Rev., 128, 650 (1966).
10) J.L. Black, H.M. Kuan, W. Gruhle, M. Suffert, andG.L. Latshaw: Nucl. Phys. , A115, 683 (1968).

196
RIKEN Accel. Prog. Rep. 22 (1988)

V.

DEVELOPMENT OF ACCELERATOR FACILITIES
1.

Ion Accelerator Development
1.

Performance of New Grid Bypass Capacitors of the Final RF
Amplifier for RIKEN Ring Cyclotron
K. Ogiwara, S. Kohara, Y. Kumata, * Y. Taniguchi, ** and T. Fujisawa

The maximum output power of the final amplifier was intended to be 300 k W in a frequency
range of 20 to 45 MHz, but at the frequency
around 40 MHz, it has been limited to 160 kW
because of the second harmonic (80 MHz) resonance between the screen and control grids of the
final tube, SIEMENSE RS2042SK, used ingrounded grid. To promote the resonant frequency higher than 90 MHz, we designed new

bypass capacitors based on a model test.I)
Figure 1 shows the cross-sectional view of the
new bypass capacitors (Cg 1 =15,000, Cg 2 =15,000pF), which consist of cylindrical capacitors
made of 50 ,urn Kapton film coated with copperon both side and disk capacitors whose insulator
are Kapton sheets (125,um). The cylindrical
capacitor is a part newly added to reduce circuit
inductance governing the resonance frequency.

Screen grid
- Control grid

final tube
Screen grid-___

SIEMENSE RS2042SK

bypass capacitor

II
Control grid

bypass capacitor

Fig. 1. Cross-sectional view of new bypass capacitors.
• Sumitomo Heavy Industries, Ltd .
•• Denki Kogyo, Ltd.

197

K. Ogiwara, et ai.

I

I

!

I

. ,.:f-t:-:":' ..J
II

.

ir

- ---- --VBIV A

i=:

I
I

.-+~

.I

I
I

I

1

~

./

Ie

J

I--

i

~--I t-:• -

IJ\ I

!

U :-:d"l(D) ~ ir-

I.....o
+>
as
I.<

/I

I

(C)

0- 1

11

1
t-- .- ' +- --

I:::

o
en
en

(B)

.....

i

.....

I

~

2
1 0-

eo

V

Vc/VA

-f--

rl.

r--'

"

-j--+--r- ==::]

+--

I

\ 1

III
$.<

+>

(A)
.................. p

G)

be

III

I

'ci

1 0-

+>

>

3

0- 4
20

30

40

-1--

-

50

60

70

80

90

100
20

30

40

50

60

70

80

90

100

Frequency (MHz)Frequency (MHz)Fig. 2. Frequency dependence of the voltage
transmission ratios from the plate terminal of
the final tube to the screen and control grid
bypass capacitors. Dotted lines show the values
calculated by the equivalent circuit shown in
Fig 3. A: resonance of tuning frequency 35
MHz, B: resonance of cathode circuit, C: resonance of the cylindrical earth for measurement,
and D: G1-G2 resonance. VA, VB, and Vc; refer toFig. 3.

Plate

o\V

f4\ 9.2Q~ 2 emFig. 4. Calculated voltage transmission ratios of
the plate to the screen and control grid.

10.6 ~2
2 .5 em

14

0 6.5

Q

38 .

6.5 emQ

em

ScreenC p,g2

Grid

83 pF

C p, g 1

6 pF

C g1.g2
390 pF

Cant rall
Gr id

CD

0

t

(0

Q

11. 0 Q

12 .0 Q

em

11 em

5 em

GNDl

G1 bypass
Capacitor

25.0

5 em

Q

43 .0

Q

2. S'- t-m

50 .0

Q

5.5 emFig. 3. Equivalent circuit of the bypass capacitors and the final tube including the attachment for measurement.
The letters A, B, and C, and the numbers 1- 8 correspond to those in Fig. 1 of Ref. 1.

198

K. Ogiwara, et ai.

The voltage transmission ratios from the plate
terminal to the screen and control grid bypass
capacitors were measured by the same method as
represented in Ref. l.
Figure 2 shows the measured ratios and thecalculated result of the equivalent circuit shownin Fig 3. An undesirable G 1 -G 2 resonance ispromoted to 97. 5 MHz, which is good agreementwith the calculation. Several resonances appeared in this measurement are explained in the
figure caption. To estimate voltages appeared at
active area inside the tube, the calculation on theequivalent circuit is also carried out. The results
are shown in Fig 4.
The power test was carried out in the frequency range of 40 to 45 MHz at intervals of 1
MHz, and the RF voltages were measured for theplate, screen grid (VB), and control grid (Vc ).
Figure 5 shows the typical wave forms of the RF
voltage in the power test.
This improvement of bypass capacitors makes
the operation of the RF amplifier system stablein the whole frequency range.
Reference
1) T. Fujisawa, S. Kohara, M. Saito, and Y. Chiba:
RIKEN Aeeel. Prog. Rep., 21, 203 (1987) .

(c)

Frequency, 45 MHz

Fig. 5. Typical wave form of the RF voltages on
power test.

199
RIKEN Accel. Prog. Rep. 22 (1988)

V-1-2.

Present Status of the Vacuum System
for RIKEN Ring Cyclotron
K. Ikegami, S. Nakajima, and S.H. Be

The vacuum system of RIKEN Ring
Cyclotron!) has been smoothly operated without
serious trouble since the cyclotron was put into
operation at the biginning of October 1986. Little
water leakage (---10- 4 Pa m 3 /s) occured at two
locations in the vacuum chamber during theperiod: one at a joint of the cooling pipe for theupper movable box of the north side RF
resonator and one at the bottom wall of copperclad stainless steel in the south side RF
resonator. In spite of the water leakage, thepressure in the vacuum chamber was held at lessthan 10- 5 Pa.
The degassing of fourteen cryopumps wasdone once a month in average. After used for
15,000 h, adsorbers of the compressors for the
cryopumps were replaced with new ones inAugust this year. Figure 1 shows a typical evacuation curve of the chamber for the cyclotron. The
chamber was evacuated from atmospheric pressure by two sets of rotary pumps (4,700 I I min)and mechanical booster pump (2,600 m 3 /h).
After pumping for 20 min to 10 2 Pa, the pumping
system was switched to four turbomolecular
pumps (5,000 lis). When the pressure become
below 10- 2 Pa, fourteen cryopumps which have a
cooling down time of 150 min were switched on.
Below 2 X 10- 5 Pa, turbomolecular pumps were
switched off and evacuation was continued byusing only the cryopumps. After evacuation for
24 h, the pressure was reduced below 10- 5 Pa;
after evacuation for 100 h, the pressure reached
below was 10- 6 Pa.

/

EVACUATION OF
TURBOMOLECULAR PUMP

~

w

!
u

100

>-

~
~ 10-1~~~ 10-2

10

100

1000

EVACUATING TIME (h)Fig. 1. Evacuation curve of the vacuum chamber for
RIKEN Ring Cyclotron.

Reference
1) K. Ikegami, S. Nakajima, S. H. Be, 1. Takeshita, Y.

Oikawa, and S. Motonaga: RIKEN Accel. Prog. Rep.,
17, 156 (1983).

200
RIKEN Accel. Prog. Rep. 22 (1988)

V-1-3.

Present Status of the Control System for RIKEN Ring Cyclotron
H. Takebe, M. Kase, I. Yokoyama, M. N agase, and S. Takahashi *Experimental halls of E4, E5, and E6 of thering cyclotron building were completed by theend of January 1989. The third part of the beamtransport system and A VF cyclotron will be
installed by the end of this fiscal year. The
control system is going to be arranged for thesedevices.
Figure 1 shows the computer network of the
RILAC and RRC control system, and the present
system of the CAMAC loop for the SSC-control
computer (M350/60-#3).1) The program-development computer (M350/ 60-#1) has a remote tty
port from the d-PBX. ** This d-PBX system canbe used for local device control or a program
M3S0/60 #1
Program Develop.
M3S0/60 #2

LINAC CONTROL

test. The program-development computer is connected to a FACOM M780/ UTS (UNIX) througha "Unix to Unix Communication Path" (UUCP,
9600 bps). A source file backup and hi-speed
calculation are done in this M780/ UTS system. A
load module program, compiled in computer #1,
can be run in SSC-control computer. So that, alibrary file is copied between them. Most of thetest programs and experimental user programs
are run in a unix operating system with a remote
tty terminal. Touch panel programs and some
programs, which are required a hi-speed execution or forked by an interrupt, are copied to areal time system (OS60) of the same computerand are run.
CAMAC crate-#5 was moved into the ion
source room from the control room and is used
for the ion source and the A VF injection beamtransport system. CAMAC crate-7# is newly
equipped in an E-power supply room and connected to the magnets power supplies and a beamdiagnostic system of the E4, E5, and E6 experimental halls. For the AVF cyclotron, magnet
power supplies, a high voltage supply, an RF
system, vacuum system, and buncher systems
will be controlled by the CIM/DIM system. Some
CIM's in CAMAC crate-#6 are also equipped
newly for the AVF control devices in aD-power
supply room. The length of the plastic fiber
Table 1. DIM and CIM number of the RRC control system.
System
RRC

Name

DIM

CIM

DAC

Magnets

56
2
1

9

284

RF
DVM: Digital Volt. Meter
BDS: Beam Diagnostic System
PBX: Telephone Exchanger
PS:
Power Supply

AVF
Fig. 1. Block diagram of the computer network and
CAMAC loop for RIKEN Ring Cyclotron.
• Mitsubishi Electric Co., Ltd.
•• Digital Phone Private Branch Exchanger (Fujitsu;
FETEX-3700).

VacuumCooling
Buncher
RIPS/ Spectr.
Magnets

1
1
4

10

RF

2

VacuumBunchers

2

Beam diagnostics
Total

1

10
1

70

7
18

364

1

65
145

H. Takebe, et al.

cables used between CIMs and DIMs is limited to
30m. Those optical fibers which exceed thislength are equipped with an opt-opt amplifier orare changed to glass fiber cables (Dupont Co.,
Ltd.). Table 1 shows DIM and CIM numbers of
the RRC control system. After installation of the
A VF cyclotron, the total number of the DIM willbe 145 and the total DAC number of the power
supplies is 364. A GP-IB interface of SSC Control
computer is expanded by using an optical interface (GP-NET; Network Supply Co. and Dupont
glass fiber Cable) into a B-Power supply (B-PS)
room and the 2nd stage of the A VF room, for
DVM for the magnet current monitoring and an
RF synthesizer control for the AVF.
A new touch panel system (Mitsubishi Electric.
Co.; DP610R) is equipped to the programdevelopment computer and being tested. As seen
in a Fig. 2, a 20-inch color graphic display and aphoto-sensed touch panel (Carol Touch Co. Ltd.)are controlled by a small computer (Digital
Computer Co. Ltd.; DP-610VT) which has 224 kB
segment memory, keyboard, digitizer, and 3.5
inch floppy disk. This DP-610VT computer isconnected to the M350/60 computer with a 9,600
bps RS-232C interface. Graphic patterns are
created in this small computer with a digitizer

Touch

Pannel

RS-232Cr-,- ~e~~o~ p,--~------J-'3.5"FDD

M350/60,7 - - - - :

II~

:

SSC
ControlComputer~

CAMAC Loop~I

I ________________________For Deve]ooement
L
JI

Fig. 2. New touch panel system using a small computer(DP610VT).

201

Fig. 3. New touch panel setup with a portable casterrack.

and stored in a segment memory, so that highspeed paging of patterns is performed with communication of a short information (tag number).
The setup is portable as seen from Fig. 3 with acastered rack. There is no compatibility in theinterface protocols between the present VT241
touch panel system and the new DP-610VT system.
A target beam current or rate meter outputs
are monitored with a personal computer (NEC;PC9801)'s ADC circuits and displayed through a
CA TV system. 2 ) A high-resolution color graphic
display signal (RGB) of the PC9801 is converted
to a NTSC video composite signal by using a
newly developed video converter (Central Engineering Co.; PVC-400).
References
1) T . .Wada, H. Takebe, J. Fujita, and H. Kamitsubo:

RIKEN Accel. Prog. Rep., 20, 170 (1986).
2) H. Takebe, S. Fujita, R. Abe, H. Akagi, T. Wada, andT. Inamura: RIKEN Accel. Prog. Rep., 21,207 (1987) .

202
RIKEN Accel. Prog. Rep. 22 (1988)

V-1-4.

Status of Construction of the Injector AVF Cyclotron

A. Goto, K. Hatanaka, K. Ikegami, T. Kageyama, M. Kase, S. Kohara,
M. N agase, M. Saito, H. Takebe, Y. Yano, and Y. Kumata *The construction of the injector AVF cyclotron started in April 1987. After completion of acyclotron magnet, magnetic fields were measured in April 1988 at Sumitomo Heavy Industries, Ltd. (SHI); the results were generally as
good as expected. From the beginning of May tothe end of November 1988, other parts of thecyclotron including a vacuum chamber, an rf
system, a main probe, a deflector, and a magnetic
channel were preliminarily assembled at SHI.
Almost all the problems found in a series of tests
in leak, operation, and rf were solved during thisperiod.
The installation of the cyclotron in the RIKEN
cyclotron vault started at the beginning ofDecember 1988; the assembling is in progress
without significant delay for completion by theend of March 1989. Figure 1 shows a photographof the cyclotron at the cyclotron vault as ofJanuary 1989 as viewed from the downstream ofthe extraction beam line. Commissioning of the* Sumitomo Heavy Industries, Ltd. (SHI).

Fig. 1. Photograph of the cyclotron at the cyclotron
vault as of January 1989 as viewed from the downstream of the extraction beam line.

cyclotron will start at the beginning of April
1989. The first beam planned is 14N5+ of 7 MeV /u. Upon coupling with RRC, the energy will go up
to 135 MeV l u.

203
RIKEN Accel. Prog. Rep. 22 (1988)

V-I-5.

Magnetic Field Measurement of the Injector AVF Cyclotron
A. Goto, H. Takebe, T. Kageyama, N. Nakanishi,
T. Tachikawa, * and Y. Kumata *The magnet system of the injector A VF cyclotron has following characteristics. The magnet isof an H-type with four spiral sectors. A polediameter is chosen to be 1,730 mm by taking
account of the extraction radius of 714 mm,
which is determined from the matching condition
to RIKEN Ring Cyclotron (RRC). A pair of plugs
made of iron to produce a central field bump are
set at a corner of the central holes through an
upper and a lower yoke. To compensate thereduction in the magnetic field near the extraction radius at high excitation levels, an iron shim
is attached to the side of the outermost part ofeach sector. Nine pairs of circular trim coils arewound on the sectors and four pairs of harmonic
coils are placed in the extraction region of valley
sections. Maximum currents of a main coil, trim
coils, and harmonic coils are 1,000 A, 360 A, and
120 A, respectively.
Magnetic field measurement was made at thefactory of the company in April 1988. After
determining the most appropriate field setting
procedure, maps of base field and trim field were
measured. Base field maps were measured foreleven levels of main coil currents. Trim fieldmaps were measured for the maximum currentof each trim coil at each level of six main coilcurrents, after confirming for a few trim coils
that the distribution is proportional to the trim
coil current. The azimuthal range of the map was
90° at intervals of 1.8 and the radial ranges were1,200 mm for a base field and 800 mm for a trim
field at interavals of 20 mm. The measurement of
360 maps was made at radial intervals of 100
mm to check the first harmonic component.
Magnetic field distributions were also measured
in the area through which an extracted beam
passes and inside the hole of a yoke throughwhich a beam from the ion source is injected.
Figure 1 shows the excitation procedure of
main coil current for field setting optimized in
the measurement. (For this setting procedure, thereproducibility of field distribution was better
than 2 X 10- 4 .) The excitation characteristics is

3min.
Max.

1113.2A

3min.
1.01

3min.
0.99
1.00
3min.

100A

2

o

5

10
Time (min)Fig. 1. Excitation procedure of main coil current forfield setting.

G

-

15 r

2S

0

0

* Sumitomo Heavy Industries, Ltd. (SHI)

15

200

400

600

800

1 000

Main coil current (A)Fig. 2. Excitation characteristics of the cyclotron
magnet.

given in Fig. 2. An average field of 17 kG, whichis the designed maximum value required, wasobtained at a main coil current of 970 A. The
radial distributions of a base field and a trim
field are shown in Fig. 3 and Fig. 4 (a) and (b),respectively. Bumps due to the plugs and the ironshim are seen in Fig. 3, in particular, at low
levels. The excitation characteristics as well as
the flutter and the betatron frequencies (v n vz )are in accordance with the design. An un-

204

A. Goto, et al.

1.09

o 1 OOOA (1 7.2 kG)
650A (13.2 kG))(
180A ( 4.7 kG)

en
en

1.06

...c

F irst harmonic amplitude

10

;:3

<0

b.o
c

2

.s 5

~

./.

t:>D

.-.--

c

.~ 1.03

~

U5

<0

~

/.

1. 00 f--..:::....:::::::......::::---...:::I.....::::---=~"""=::b-~=:-..-'--==---\-1r4-1
0100

Radius (mm)
0.97

.,/'"

)(

.:::::::::::--)(-)(-)(--)(~

200

300 400 500
Radius (mm)600 700

Fig. 5. Radial distributions of the first harmonic fieldat several excitation levels.

Fig. 3. Radial distributions of a base field at six excitation levels.

80
en
en

Averaged field strength
at the extraction radius = 15 kG

;:3

C<l

240
c

o

'';::

Main coil current = 390 A

450__~__----------~#8

<0
.;;:

400

~

0~~~L-~--~~L-------L-~~-8~00

-0

a::;
~

- 40
~300
;:3

<0

2

- 80

Fig. 6. Difference between the ideal isochronous field
distribution and that predicted for 7 MeV l u 14N s + ion.
-0

~

~

Or-----~~~~~~~--~--~--~~~
800
Radius (mm )

-150

Ca)

450

~
300
;:3
<0

2

Main coil current = 1 OOOA

#2

...c

~ 150~----~----======~

ben
-0

a::;

~

0r---~~~~~~~~~~~~~~
Radius (mm)expected first harmonic field appeared at higher
excitation levels as shown in Fig. 5. The direction of this field lay nearly along one of thesector-center line. We found, however, from thecomputer simulation that this occurrence is tolerable and the designed extraction energy can beobtained.
The data base of average fields along equilibrium orbits, which will be used to produce anisochronous field, was deduced from the resultsof the measurement. In order to check thepredictability of the method, the field distributions calculated by using the data base for the 7
MeV l u 14 N5+ ion, which is expected to be thefirst beam, was excited and measured over therange of 360 Figure 6 shows the difference
between the ideal isochronous field distribution
and the measured one. The result indicates thatthe prediction is satisfactory for the initial setting of an isochronous field distribution.
0

- 150

•

(b)

Fig. 4. Radial distributions of a trim field for nine trim
coils (a) at a main coil current of 390 A, and (b) at
1,000 A.

205
RIKEN Accel. Prog. Rep. 22 (1988)

V-1-6.

Design of the Central Region of the Injector AVF Cyclotron
A. GotoThe injector A VF cyclotron is a type 750 PV of
Sumitomo Heavy Industries, Ltd. (SHI), modified
so as to be used as an injector for RIKEN Ring
Cyclotron (RRC). One of the most significant
changes from the 750 PV is the central region of
the cyclotron. To design this region, a computer
program has been developed that simulates abeam orbit, the acceptance of the cyclotron, andso on. Principal requirements are 1) a beam

should be accelerated on a well-centered orbit, 2)
the acceptances of the cyclotron in (r, r') and(z, z') phase spaces should be as large as possible, and 3) the phase of a beam can be cut
effectively with a phase defining slit. The optimal combination of the shape of a central fieldbump and the configuration of a central electrode of the rf resonator were searched to meetthese requirements.
_5°

o

50

100 mmInflector

~-200

+10·

Z-AcceptanceR -AcceptanceFig. 3. Acceptances of the cyclotron in both horizontal
and vertical directions for various injection phases.
'(( CM J

DeeFig. 1. Designed layout of the central region of thecyclotron.

12

4

EE

2

~ O~~~--~~~L-~~~~~~~

Phase
slit

""-2

-4

12
XC CM Jl;~Uva"
0:::0

""-2

fJ (de g)-4
DeeFig. 2. Motions of two particles in both horizontal andvertical directions for the first two revolutions. The
two particles are orthogonal to each other lying oneither horizontal or vertical phase ellipse whose area is
7! x 2.5 mm x 40 mrad. Arrows and values indicate thepositions of the first four gaps and the rf phases when
the particles pass through the gaps.

Fig. 4. Dependence of trajectories for the first few revolutions on the injection phase. Trajectories with theinjection phases of O· and ± 10· are simulated, eachconsisting of three particles: the central particle andtwo particles orthogonal to each other lying on thephase ellipse whose area is 7! x 2.5 mm x 40 mrad.

206

A. GotoThe layout of the central region thus determined is shown in Fig. 1. The peak of the central
field bump is 1 %. Drift-tube-like pillars, which
form a rectangular aperture, are placed at thefirst two gaps. The nose part of the electrode isremountable for maintenance or repair. Figure 2
shows the motions of selected two paricles inboth horizontal and vertical directions for the
first two revolutions. Acceptances of the cyclotron in both directions are shown in Fig. 3 forvarious injection phases. This figure indicatesthat calculated acceptances within the injection
phases of ± 5° or more cover an expected beamemittance of about 100 7C mm emrad from the

ECR source. (Note that the gap of the inflector is
5 mm.) Here the definitions of acceptance are
given by that, up to a radius of 20 cm, particles
should lie within the distance of ± 5 mm and ±10 mm from the central particle in the horizontal
and the vertical directions, respectively. A movable phase defining slit is set in the first turninside the dummy dee. The computer simulation
indicates that the slit is very effective because at
this place not only a beam spreads radiallyaccording to phase but also it shrinks withrespect to the radial emittance as shown in Fig.

4.

207
RIKEN Accel. Prog. Rep. 22 (1988)

V-I-7.

Calculation of the Extraction Orbit for the Injector AVF Cyclotron
T. Kageyama and A. Goto

The beam extraction system for the injector
A VF cyclotron consists of an electrostatic deflector and a magnetic channel which peel off abeam from the last acceleration orbit, and a
gradient corrector which focuses the beam horiHagnetic Channel
Gradient

Phase Slit /P 0 sit ion A

Beall
Vacuu. Chamber

100 c.

Fig. 1. Layout of the extraction system in the AVF
cyclotron.
20

;--,

a
u

15

c::
0

......

.....

...'"
'"

10

Cl.
<ll

'"
a

'"

Q.)

=

-30

30
Azimuthal

60

90

angle

120

150

180

(deg)

Fig. 2. Beam separation between the extraction
orbit and the last internal orbit for 7 MeV l u 14N5+
ions as a function of the azimuthal angle in the
A VF cyclotron. Def., deflector; M. C., magnetic
channel; G. C., gradient corrector.

zontally. The gradient corrector is of a passive
type. The layout of the system is shown in Fig. 1,
together with some other main components ofthe cyclotron.
To determine a beam trajectory in this system,
we chose a 7 MeV lu 14N5+ ion as a reference
particle. The initial beam parameters at theentrance of the deflector were obtained by tracing a group of particles from the exit of an
inflector (the injection point) with a programcode A VF4. Emittances at the exit of the inflector were assumed to be 7! x 2.5 mm x 40
mrad, 7! X 2.5 mm x 40 mard, and 7! X 6° x 1%,
in a horizontal, a vertical, and a longitudinal
directions, respectively. A program code A VFEXT was used to calculate the extraction orbit
from the entrance of the deflector up to theextraction hole of the vacuum chamber (at the
point A in Fig. 1). In AVFEXT the fields of thedeflector and the magnetic channel, and the field
gradient of the gradient corrector were superimposed on the field distribution produced by themain coil and trim coils.
Figure 2 shows a beam separation between theextraction orbit and the last acceleration orbit
for 14N5+ ions of 7 MeV lu. In general, the extraction orbit varies with the excitation level of themagnet, because the shape of fringe field distribution changes with the excitation level. To see
the difference, we calculated extraction orbits
for several fringe field distributions, i. e. for several excitation levels. Figure 3 shows examplesof the dependence of extraction orbit on the main
coil current. Deviations from the reference orbit
at a main coil current of 685 A ccorresponding to
7 MeV lu 14Ns+) are shown for main coil currentsof 200 and 1,000 A. As can be seen from Fig. 3, thebeam position changes as long as about 8 mm at
the entrance of the gradient corrector in order totransport a beam into the center of the hole atpoint A.
Beam sizes along the extraction orbit werealso calculated by using AVFEXT. Figure 4
shows the change in the beam sizes in the horizontal and vertical directions for 7 MeV lu 14Ns+
ions. A horizontal focusing and a verticaldefocusing with the gradient corrector can be

208

T. Kageyama, et at.
15

20

....

-<

....

OJ

OJ

c:>

1>0

10
c:::

0

.

e

+"'

'-'

;;

c:::

c..

0

'"

..
~

i!
i'
l:

10

! )i

IIi i

ClI

""
··· · ···~-,i1000 A

,

~.

\

"

to R

!

..,'"

~

'"

c..

'"'
II

.

+"'

-

II)

i I
! !
: i

c:::
.~

'"'
a

i Iu
I I .
I !E
i i

to z

~(

.\
-5
-3 0

30

60

90

12 0

15 0

1 80

2 10

- 30

30

60

90

120

Azi.uthal angle
Azi.uthal angle

150

180

210

240

24 0

(deg)

(deg)

Fig. 3. Dependence of the extraction orbit on the
excitation level of the magnet. Deviations from thereference orbit (14N 5 + ion of 7 MeV l u; the main
coil current is 685 A) for main coil currents of 200
and 1,000 A.

Fig. 4. Beam sizes calculated along the extraction
orbit in both horizontal (J R) and vertical (J Z)
directions. 14N5+ ion of 7 MeV l u was taken as an
example.

Table 1. Calculated horizontal beam sizes at theexit hole of the vacuum chamber (position A in
Fig. 1) for various excitation levels of the magnet.

(A)

Field gradient inside G. C.
(kG/ em)Beam size
(mm)

200
390
540
685
820
1,000

0.9
1.6
2.0
2.2
2.3
2.4

9
19
17

Main coil

20

r-.

e
e

10

~

11

18
18

.,e
<0

120

15 0

180

210

240

Azimuthal angle (deg)Fig. 5. Dependence of the beam sizes in the horizon·tal (J R) and the vertical (J Z) directions on thestrength of field gradient of the gradient corrector
for 7 MeV l u 14N5+ ions (the main coil current is 685
A).

seen from Fig. 4. To see the effect of the gradientcorrector, the beam sizes after the gradient cor·
rector were calculated for several field gradi·
ents. The beam size in the horizontal direction
was found to be strongly dependent on thestrength as shown in Fig. 5. Table 1 gives thecalculated horizontal beam sizes at point A for
several excitation levels of the magnet. In thecalculation the measured values were used forthe strength of field gradient of the gradientcorrector. The results show that the beam size
can be kept rather small with this gradient corrector of a passive type at all excitation levels
despite the sensitivity on the strength.

209
RIKEN Accel. Prog. Rep. 22 (1988)

V-I-B.

Measurement of the Characteristics of a Resonatorof the Injector AVF Cyclotron
S. Kohara, A. Goto, and Y. Kumata*The electrical characteristics of a resonator of
the injector A VF cyclotron for RIKEN Ring
Cyclotron (RRC) were measured with a low-levelsignal at Sumitomo Heavy Industries, Ltd. in
September 1988. The cyclotron t has two
resonators,tt which are of the coaxial quarterwave-length type with a dee angle of 83°. A crosssectional view of the resonator is shown in Fig. 1.
The frequency range is from 12 to 23 MHz. A
shorting plate is used for coarse tuning and aNo.1 Resonator; o. l;.. 0
No.2 Resonator ; . , ' , .

4000

Q

Q)

;J

3000 ~
>
I

2000

a

>.

..!l::

oc:

Shorting plate

Of

Ql

g. 15

II)

Q)

....M

150

Il:
Q)

.j.>

0

c:
as
t::
o

c:
as
100 'd
Q)

II)
Q)

P-

Il:

50

....el

.j.>

c:

;3

.t:
til

100

200

Position of shorting plate

em )

L

Fig. 2. Resonant frequencies, Q-values, and shunt
impedances measured as a function of the position of
the shorting plate. Solid lines are the calculations basedon a transmission line approximation.

0 : 12 MHz
D. : 16 MHz
0 : 20 MHz

0
TerOlinal for coupl ing capacitor

~

N

800

::r:

.

• : 24

-200

.Ii
®

..,

....
.,.,

~

..s::

Ul

0

e

>.

g-400

Fig. 1. Cross sectional view of the resonator.
* Sumitomo Heavy Industries, Ltd. (SHl).
t This cyclotron is based on the SHI model 750 PV andmodified to meet the requirement as an injector.
tt SHI patent.

0

!:,.

0'

0

~

~

~

0

-600
Dee vol tage pickup

0

Ql
;::I
Ql

Capacitive tuner

MHz

0

.!C

20

40

Rotation angle of tuner

0

0

~

.!,.

0

0

60
(

deg.

Fig. 3. Frequency shift of the capacitive tuner.

80

210

s. Kohara, et at.

capacitive tuner for automatic fine tuning. The
driving speed of the shorting plate is 32 em/ min.
The contact fingers of the shorting plate arepressed with a pneumatic pressure of 5 kg/ cm 2 •The rotation angle of a capacitive tuner is 90°.
Ceramics insulators are used for support of astem and a dee as well as for a vacuum seal.
Resonant frequencies, Q-values, and shunt
impedances measured as a function of position of
the shorting plate are shown in Fig. 2 for two
resonators. No significant differences were seen

between the characteristics of the two resonators. The measurements were reproduced well by
calculation based on a transmission line approximation as shown in Fig. 2. The traveling lengthof the shorting plate is 1.8 m for the required
frequency range. Frequency shifts as a functionof rotation angle of the capacitive tuner were
measured and are shown in Fig. 3. Frequency
coverage of the tuner is wide enough to compensate a frequency shift due to heat in normal
operation.

211

RIKEN Accel. Prog. Rep. 22 (1988)

V-I-g. Power Test of the RF System for the Injector AVF Cyclotron
S. Kohara, M. N agase, M. Saito, T. Kageyama,
A. Goto, T. Fujisawa, and Y. Kumata *The RF amplifier system of the injector A VF
cyclotron for RIKEN Ring Cyclotron (RRC) was
preliminarily assembled at Sumitomo Heavy
Industries, Ltd. (SHI) in October 1988. The excitation test of the resonator was also carried out
there; the characteristics of the resonator had
been measured beforehand. 1) The power amplifier system consists of a solid-state wide-band
amplifier (500W) and a grounded-cathode tetrodeamplifier (EIMAC 4CW50,000E). An all-pass network is adopted in the input circuit of the tube.

The specifications of the amplifier system were
presented previously.2)
Figure 1 shows the equivalent circuit of theplate load of the tube (see Fig. 1 in Ref. 1). The
amplifier is capacitively coupled t to theresonator with a coupling capacitor (Cc ). The
output capacitance (4) of the tube was measured to be 75 pF. The load impedances (2;,) of
the tube and the ratios (Vc/ Vd ) of the voltage at
the coupling position (Vc) to the dee ' voltage(Vd ) are shown in Fig. 2. The ratio decreases as
the frequency increases because the inductance(L z ) decreases as the frequency increases. The
load impedance thus becomes very low at highfrequencies.
The results of the power test for several frequencies are shown in Table 1. Required accelerating voltages were obtained in a frequency
range from 12 to 22 MHz. At 23 MHz, however,
the required accelerating voltage could not be
obtained with the wide-band amplifier whose
maximum output power is 500 W. This is because
the load impedance is too low at this frequency.

Resonator

r-············································,·,·,··.,.,... ,..... ,.,.j

i

1'
cc

z p -+

i

Vc;

!

i

r-~-:<

OI-----..r-

I

:

i

Cp.7S pF

R

i

i
!

j

:

i

!

:L................_.................................................................................. ...... _:. :I
Fig. 1.

Load circuit of the tube.

Table 1. Measured results of operational conditions of the amplifier. RF voltages are peak values.
Final amplifier
Frequency

Pre·amplifier
output power

(MHz)

(W)

Screen gridcurrent
(rnA)

12
13
14
15
16
18
20
22
23

270
310
340
370
450
300
310
460
480

5
10
20
20
30
5
2
0
0

DC plate voltage: 10k V
DC screen voltage: 1,200V
DC control voltage: - 300V

* Sumitomo Heavy Industries, Ltd. (SHI).
t SHI patent pending.

Platecurrent(A)

RF control
grid voltage(V)

RF plate
voltage(kV)

Accelerating
voltage
(kV)

1.2
1.6
1.8
2.0
2.5
2.2
2.4
3.1
3.0

120
140
140
160
160
150
150
180
160

7.8
7.6
7.0
6.7
6.6
4.0
2.8
2.4
1.7

41
43
45
48
50
36
32
33
28

212

S. Kohara, et al.

Cc=12 pF

1.0
lJ

>

"U

6
6

>

Vc/Vd
6

0

0
~

III

c:

I-

6

::.::

QJ
bQ

III

6

~

rl

O

P-

N

0

2

0.5

>

41
0

s::
CIl

0

'd
41

PE

0

......

In the above measurement a fixed capacitor of
12 pF was used for the coupling capacitance.
This value was low to some extent for highfrequencies. It is desirable to use a variablecapacitor in order to get good impedance matching between the amplifier and the resonator.
However, because a variable capacitor initiallyinstalled had been broken in the excitation test,
the fixed capacitor was used tentatively. The
coupling capacitor is planned to be replaced
from 12 to 16 pF to get the required accelerating
voltage at 23 MHz as well in the power test thatwill be carried out at RIKEN in the spring of1989 .

Zp
0
0

12

16
Frequency

20

References

0

24

( MHz

Fig. 2. Load impedances of the tube and the ratios of thevoltage at a coupling position to the dee voltage.

1) S. Kohara, A. Goto, and Y. Kumata: This Report, p.
209.
2) S. Kohara, M. Nagase, M. Saito, T. Kageyama, A.
Goto, and T. Fujisawa: RIKEN A eeel. Prog. Rep. , 21 ,214 (1987).

213
RIKEN Accel. Prog. Rep. 22 (1988)

V-I-IO.

Beam Buncher in the Injection Beam Linefor the Injector AVF Cyclotron
K. Ikegami and A. Goto

A beam buncher has been developed for efficient bunching of D.C. beams from the ion source.
The buncher is to be placed in the injection beamline at 2 m upstream from the inflector set in thecenter of the median plane of the A VF cyclotron.
The buncher consists of two parallel mesh plates
forming a single accelerating gap, and is excitedby an RF voltage with a sawtooth-like waveform. The sawtooth-like wave calculated by
combining RF sine waves with the first threehigher harmonics is shown in Fig. 1. The combined RF voltage Vb is given by Vb = Vo (sinwot+ 1/3 sin2wot + 1/9 sin3wot). Figure 2 shows a
block diagram of the buncher circuit. A fundamental frequency range is 12-24 MHz. Required
peak-to-peak amplitudes of fundamental, second
harmonic, and third harmonic frequencies are

+1T

vb
=O
V (sinw t
O+

1/3sin2w t + 1/9sin3w t)_~

shifter

cmtrollerf.

-'------';--------- ------~--- -- --- ----- ---- ----- --- -- ------- -- ---- ---------- -- -- Picking up-------------------- ---------.---------- vol~/phase

2 f.

Si~

--'lI

fMse

~

Level

divioorshifter

cmtroller

r--

'----

'------'~

Signalconbioor~ Fbler

CIIlpl if ier~ Hatchingf--+-~

transforrer

Je; is tanre

3f. ~·· .. ··--·--··-r·-·-·--··~

shifter

cmtroller

RF si~ froo the AVF ~lotro1

Fig. 2.

0

Fig. 1. Sawtooth-like waveform calculated by combining RF sine waves with fundamental (wo), second
harmonic (2wo), and third harmonic (3wo) frequencies .

··.. ... _---.--------_._-_._._--------_._._------------------------------_._-------.
..
:

0

Block diagram of the buncher circuit.

200 chns

Bundler214

K. Ikegami, et al.

Etched copper
tresh

Fig. 3. Schematic drawing of the electrodes of the beam
buncher along the beam axis.

750V, 450V, and 150V at the maximum, respectively. The stabilities of the voltage and thephase should be within less than ± 1 x 10- 3 and± 0.5°, respectively. The combined RF voltage isapplied through a matching transformer to oneof the two electrodes to which a resistance of 200
n is connected in parallel. A combination of thematching transformer and the resistance of 200 n
is used to decrease the combined RF power as
low as possible. The maximum required RF
power is 500 W. Figure 3 shows a schematic

dra wing of the electrodes of the beam buncher
along the beam axis. Two electrodes with tortoise shell (hexagon)-shaped mesh are made ofetched copper plates and are insulated withceramics. The size of the hexagon is 2 mm. Bothwidth and thickness of the mesh are 0.1 mm. The
gap between two electrodes is 5 mm and thediameter of the mesh section is 60 mm. The beamtransmission of the mesh is estimated at morethan 83 % (0.91 x 0.91) .

215
RIKEN Accel. Prog. Rep. 22 (1988)

V-I-II.

Model Study of the Beam Rebuncher for the Injector AVF
Cyclotron and RIKEN Ring Cyclotron
A. Goto, M. Saito, S. Kohara, and R. Abe*A beam rebuncher was designed for use in the
beam transport line between the injector AVF
cyclotron and RIKEN Ring Cyclotron (RRC).
The design concept is almost the same as that of
the beam rebuncher used in the beam transportline between RILAC and RRC.l) A fourth harmonic mode with respect to the rf frequency of
the A VF cyclotron was adopted to help reducethe maximum required voltage and the length ofgap separation. (Note that the rf frequency of
RRC is twice that of the A VF cyclotron.) A
multi-gap system was also adopted for further
reduction of required voltage. The characteristics of the beam rebuncher thus determined bytaking ion-optical calculations into account are
as follows:
Frequency range
48- 90 MHz
Harmonics
4
N umber of gaps
3
Maximum peak voltage per gap 40 kV
Width of each gap
25 mm
Separation of gaps
280 mm
40 mm
Aperture of beam transmission

A 1/ 3-scale model of the beam rebuncher wasconstructed, and its electrical characteristics
were measured. Figure 1 shows the schematic

drawing of the model.
The resonator is of a shielded Lecher-wires
type with two stems. At the end of each stem adrift tube is mounted, which forms three gaps.
The resonant frequency is adjusted with a shorting plate and a pair of capacitive frequency
tuners. The rf power is fed into the resonatorthrough a 50 n coaxial feeder line coupled withthe resonator by a tunable capacitive coupler.
Measurement was performed for a few combinations of positions of the capacitive frequency
tuner (d) and the shorting plate (s), whose
definitions are given in Fig. 1. Figure 2(a) gives
resonant frequencies, Q values, and shunt
impedances against s for d = 95 mm (max.); Fig.
2(b) is the same as Fig. 2(a) except for d = 10 mm.
In these figures the results and the values of sand d are converted for use in the actual scale bymultiplying a scale factor. The shunt impedance
was obtained with a perturbation method using adielectric ceramic bead. Calculations with atransmission line approximation are comparedto the data for three values of capacitances
produced by the drift tubes and the frequency
tuners.
By taking the above results into account, theIt-----Jt---+-J--I--.:=J:::= Inn e r
conductor

10 20

30

40

50cm

Fig. 1. Schematic drawing of the model rebuncher.
* Sumijyu Accelerator Service, Ltd.

216

A. Goto, et al.
90r-~~----------------~

90r--------------------~

12000

Zo=730--C=24pF----- C=30pF---- C=35pF
d=10mm

11000
CI)

80

Zo=730- - C = 19pF-----C=15pF---C=10pF

10000

:::J

-;;;
>I

12000
11 000CI)

10000 -;;;:::J
>I

~

9000

~

9000

8000

8000

d= 95 mm (max)

'Q

c.
c

/Q(meas)(meas)

"-

500

'"c
Jl 60

500

'2
400 .=.

o'2

400 .=.

~

~

c

c

300 .5300 .5

"iii
'"

'"

"iii

Q)

CI)

200 0:::

200 0::::::J..c
100 en:::J..c
100 en

-;:

50

50

100

-;:

150

100
150
'Position of Moving Short [em]"Position of Moving Short [em]Fig. 2 (a) . Measurements of resonant frequencies, Q
values, and shunt impedances against the position of the
movable shorting plate for d=95 mm (max.). Calcula·tions using a transmission line approximation are also
shown for comparison for three values of capacitances
produced by the drift tubes and the frequency tuners.

Fig. 2 (b) . The same as Fig. 2(a} except for d = 10 mm.

desigh of actual beam rebuncher has been fixed.
The length of a stem (s) was chosen to be 90 cm
and the maximum power of a power amplifier tobe 3 kW. The outer tube of the shielded Lecherwires part has been decided to be a cylinder
rather than a racetrack shape because of easiness of fabrication. The beam rebuncher systemis scheduled to be completed by the end of March
1989.
Reference
1) A. Goto, T. Fujisawa, and I. Takeshita: RIKEN

A ccel. Prog. Rep., 18, 184 (1984 ) .

217
RIKEN Accel. Prog. Rep. 22 (1988)

V·l·12.

Rotational Beam Scanner

M. Kase, I. Yokoyama, and M. Saito

A rotational beam scanner was made and installed in a momentum analysing section of thebeam line from the injector linac (RILAC) to
RIKEN Ring Cyclotron (RRC). With this scanner,
one-dimensional beam profiles can be measured
continuously. For a well-tunned beam, the scanner can work as a monitor for a beam energy andits spread as well as a relative beam intensity.
Figure 1 shows a schematic diagram of therotational beam scanner. The detection part is atungsten straight wire of 0.5 mm in diameter and
40 mm in length, supported at its one end with arotational ceramic arm. The wire moves on acircle of 60 mm in diameter around a rotation rod
which is perpendicular to the beam axis. As aresult, the wire scans a beam twice every turn in
different directions. The rod is introduced out ofa vacuum chamber through a magnetic-fluid
vacuum seal, and there connected to three components. The first one is a dc motor, which candrive the scanner over 60-1,200 rpm throgh gears.

~---

DC MOTORr-----ROTARYCONNECTOR

r-----POTENT 10METER

The second is a potentiometer, which generates a
voltage signal approximately proportional tosine of a rotational angle of the rod. It gives a
distance of wire from the beam axis after some
calculations. The third components, a mercurytype rotary connector, is combined directly to therod, permitting an electric connection between arotated signal line from the wire and a fixed
BNC connector with a low noise level. Thesemechanical components were selected in viewthat they can stand for a long-term and continuous use without any maintenance.
Electronics is shown in Fig. 2. The position
signal becomes -10 to 10 V through an amplifier, AMPl. The current signal from the wire isconverted to a voltage signal (- 10 to 0 V) with again-controllable amplifier, AMP2. These two
signals, after passing through sample holders,
are fed to analog inputs of DIM (Device Interface
Modulel). Turning on/off of a motor power
supply, gain-control of AMP2, and a trigger tothe sample holder are done by DIM with digital
I/O ports. DIM samples the two analog signal
periodically (typically every 2 ms), stored thesedata in a 2 kB memory, and, after a memory
becomes full, transfer the data to a host computer (Mitsubishi M60 for RILAC control). DIM
repeats these processes every few seconds.
Sample Holde r

AM PI

DIM

POTENT 10METER~---- MAGNETIC-FLU ID

AnalogInput

VACUUM SEAL

Serial
Port

WIRE

CIM

L _ _ _ ~=;:===~ Digi tal
110

MOTOR

Fig. 2. Electronics for the rotational beam scanner.

Figure 3(a) and (b) show a set of typical raw
data obtained in one measurement. Because of atime variation in beam intensity, for obtaining a
reliable beam profile, it is necessary to scan abeam several times during one measurement, and
t

'WIRE

Fig. 1. Schematic view of the rotational beam scanner.

218

M. Kase, et at.

~ l~~27\v<ITI~ (~I-10 ------... "-' . -- .. -..... - . ... _.._-.- ... - .-.--. ---.---..... - .. ---'--"

Fig. 3. Data for position (a) and beam signal (b), which
are taken by DIM.

<I:

c

I

30

::E:

~

<XI

-30

-20

-10
POSITION

Fig. 4.

10

20

30

(mm)

Beam profile obtained from the data in Fig. 3.

to convert these data into a beam profile. Thus
obtained profile are shown in Fig. 4. The computer shows a beam profile on a colour graphic
display of the operational console and also immediately calculates an averaged beam position, abeam width, and the area of the distribution.
Since the beam scanner is installed at a
momentum analysing section of the beam transport line, after a beam is tunned, the beam position gives a relative beam energy from RILAC; aposition shift of 1 mm corresponding to anenergy variation of about 0.1%. The beam width
gives a rough idea about an energy spread in thesame way. If a noise effect is subtracted from thearea of the beam profile, the area should be
proportional to the beam intensity. Once calibration is done with a Faraday cup at the same
position for each kind of beam, it can also work
as a beam intensity monitor. These measurements can be made down to a 1 nA beam (in caseof Ar beam, for example) with fairly good accuracy.
For an efficient operation of RRC, it isrequired to keep the injector as stable as possible. For monitoring the stability, this beamscanner will be very helpful. Since the averaged
fraction of a beam interrupted by the wire is lessthan 0.6%, the continuous measurement is possible. The latest data are immediately transferred to a main computer of RRC via a local area
network between computers. At a operational
console of RRC, one can see the variation inenergy, its spread, and intensity of a beam fromRILAC, when necessary.
We plan to use this scanner on every stage ofaccelerator, that is, at exits of ion sources andthe new injector (A VF cyclotron) and also at theexit of RRC itself, and to construct a beam stabilizing system for the whole accelerator using
these scanners.
Reference
1) M. Kase and I. Yokoyama: RIKEN Accel. Prog. Rep.,

21, 201 (1987).

219
RIKEN Accel. Prog. Rep. 22 (1988)

V-1-13. Status of the RIKEN Electron Cyclotron ResonanceIon Source (ECRIS) for an Injector AVF Cyclotron
K. Hatanaka, H. N onaka, E. Ikezawa, and W. Yokota
An ECR ion source for an AVF-ring cyclotron
complex has been constructed. The source, assembled and pumped down on April 8, 1988, isused to produce highly charged ions for relatively heavy elements (up to Ca). The first plasma
was ignited on April 11, and an Ar 8 + beam was
successfully analyzed with the intensity of 15 J1.A
on April 13. The source has been operated mainly with gaseous elements since then. Throughfurther half a year development, the beam fromthe source will be axially injected into the A VF
cyclotron.
The design of the RIKEN -ECRIS was discussed elsewhere. 1,2) The source consists of twostages: the first stage, 6 cm in diameter and 25 cm
Table 1.

Charge state

1
2
3
4
5
6
7
8
9
10
11
12
13

14
15
16
17
18
19
20
21
22

long, is used for plasma filamentation and thesecond stage, 10 cm in diameter and 52 em long,for production of highly charged ions. It is provided with three gas feeding lines: two at the firststage and another at the second stage for gas
mixing.
After some improvements, the source has
intensively operated since June 20. Up to now,ions are produced for nine kinds of gaseous
elements. The present source performance issummarized in Table 1. These currents represent
the "typical best" results from the source with anatural isotopic abundance. In the table 1, maximum energies attained with the AVF-ring cyclotron complex are listed for ions which can be

Ions from RIKEN ECRIS.

12C

14N

160

19F

2°Ne

32S

4°Ar

84Kr

129Xe

CO 2+He

N 2+He02+ HeCHF 3+ He

Ne + He

SF 6+0 2

Ar+0 2

Kr+0 2

Xe+02

85

300
230
155
110@
24

180
225

*

56@
12

*

120@
125
20

45
46
33

110
115

*
18@

95
50@
35
1.1

*

0.05

*

11

*
24

52

*

95
87

16©

*

2.4

*

0.025

72

*

300
10
2.2
0.5

Currents in e J..I. A.
13 k V extraction voltage (10 k V for Xe).
Final beam energy at the ring cyclotron is 135 MeV l u (@), 110 MeV l u (© ), 95 MeV l u (0 ).

20
23

*

27
25
15
5.3
2.5

*

1.6
0.6

*

0.1

4.8
5.0
5.0

*

5.0
5.5
5.5
5.2

220

K. Hatanaka, et at.

accelerated by the injector AVF cyclotron. For
all elements, gases are fed only to the first stage.
Gas flow rates are not measured directly, but arecontrolled by monitoring the pressure of the firststage. Usually, the pressure is 4 X 10- 5 , 3 X 10- 6 ,and 2 x 10- 7 Torr at the first, second, and extraction stage, respectively. Typical RF powers of 50
Wand 800 Ware fed to the first and second

stage, respectively. The extraction voltage is 13
k V except for Xe (10 k V). Figure 1 shows aschematic drawing of the charge analyzing system. Openings of SLITs 1 and 2 are 20 mm in full
width for lighter elements up to Ar. They are
reduced to 10 and 2 mm for Kr and Xe, respectively, in order to resolve adjacent peaks. Figure
2 shows a typical spectrum obtained with Xe.

90 0 BENDING MAGNETECR ION SOURCEPROFILEX·RA Y SHIELD

2M

0. 5

Fig. 1. Schematic drawing of the charge analyzing system .
Tuned for
Extraction voltage
Gas
RF
Vac.

Analyzing slit width. Xe25 +: 10 kV: Xe + 02: 20 W (1st stage): 800W (2nd stage): 2.2xlO· 5 Torr ( 1st stage): 2.0xlO- 6 Torr (2nd stage): 1.3 x lO· 7 Torr (ext. stage): 2 mm~8+

analyzing magnet current

Fig. 2. Charge state spectrum with Xe.

221

K. Hatanaka, et al.

Table 2.

Gas mixing effect.

IZC
Gas
CS.
2
3
4
5
6
7
8
9

CH 4 +O Z

COz+ OzzONe
COz+He

41

85

85

*
6.3

*
37

*
56

0.3

2.3

12

Table 2 summarizes the performance with different combinations of gases for C and Ne. It can beseen that helium is a better support gas for Ne
than oxygen. For the carbon beam, CO 2 gas gives
better performance than CH 4 gas. A similar
result is obtained with a PIG source. From thebeam size measured at the SLIT 2, the emittanceof the beam from the source is estimated to beless than lOO7r mmemrad, which is smaller thanthat assumed in the design of the beam transportsystem.
A low temperature oven for solid elements wasconstructed and preliminary tests have been
performed with magnesium. Oxygen gas was fed

Ne+Oz

Ne+He

110
115

110
115

*

63
24
14
0.3

*

95
50
35
1.1

to the first stage for plasma filamentation, andmagnesium vapor was introduced to the second
stage. A 24Mg7+ beam was obtained with theintensity of 3 J1.A. Further improvements are
required to extract more intense beam from thesource.
References
1) K. Hatanaka, H. N onaka, and H. Kamitsubo: Proc.

Int. Conf. ECR Ion Sources and Their Applications, p.
353 (1987).
2) K. Hatanaka and H. Nonaka: RIKEN Aeeel. Prog.
R ep., 21, 212 (1987).

222
RIKEN Accel. Prog. Rep. 22 (1988)

V-1-14.

Basic Study of a Polarized 3He Ion Sourceby Laser Optical Pumping. I

T. Fujisawa, A. Minoh, Y. Taniguchi, S. Ishii,
K. Hatanaka, and Y. Oshiro*

Despite a polarized 3He-ion beam is very usefulto study nuclear physics, no extensive development of the source has been made since the firstpolarized beam was accelerated in 1968,1) andonly three ion sources are at work in theworld. 1 - 3) Recently, a new method was developed
to produce polarized 3He by laser opticalpumping 4 ) and ECR ion sources deliver highintensity beams of high charge state heavy ionsvery stably. We study a new polarized 3He ion
Ionization

l083nm

21 S0-=

Fig. 1. Energy levels of 3He atom in an external magnetic field. See Ref. 5.

source consisting of a laser system and an ECR
ionizer. The procedure of the optical pumping
has been known 1.5} but no powerful light source
had been available. Figure 1 shows energy levelsof 3He atom in an external magnetic field. The
23S 1 metastable state has a long lifetime (4,000 s)
and the 2P state spontaneously decays to the 2S
state by emitting the light (1,083 nm). Thus the 2S
state atom and a 3He nucleus can be polarized if
the 2S state atom is excited to the 2P state in amagnetic field by absorbing the circularly polarized light which travels along the magnetic field,
because the z-component of spin of the circularly
polarized light is 1 or -1 corresponding to its
polarization. Figure 2 shows a block diagram ofthe polarized 3He ion source proposed. The 1,083
nm linearly polarized light is produced from a
LNA crystal excited with an Ar laser (514 nm)
and polarized circularly by a quarter wavelengthplate. In the RF discharge region where a weakmagnetic field is supplied, the ground states of
3He are excited to the 2S triplet states by an RF
electro-magnetic field, and the 2S states are
excited to the 2P states by circularly polarized
light. The polarization of the 2S state transfers
to the ground state. The polarized atoms aretransported into the ionization region and ionized by an RF field (28 GHz, 1 kW) in a static
magnetic field (about 1 Tesla) strong enough to

RF-Discnar,e'andOptical Pump.

ECR-Ionizer(1 Te s 1 a)andExtractor

Fig. 2.

Block diagram of a polarized 3He ion source by laser optical pumping.

* Institute for Nuclear Study, University of Tokyo.

T. Fujisawa, et al.

hold the nuclear polarization. The study of thedischarge system is described in the present
report and the development of the laser system ina separate one of this progress report. 6 )The 2S metastable states are created by several method, for example, by RF discharge, DC
discharge, or charge exchange reactions ofatoms. We tried to create the 2S state by RFdischarge with the dissociator of the atomic

II I~pyrex
l1n~6mm-lL
2mmof>

1m

Fig. 3. Atomic beam type polarized proton and deuteronion source at INS of the Univ. of Tokyo.

1 083nm Light intensity
2P -+ 2S Transitiono High pressure (1.1 torr)I:.

Low pressure (0.2 torr)

0

8

(;)

(;)

o
-

Fig. 4.

Incident power (W)Intensity of 1,083 nm light from a dissociator tube.

223

beam type polarized ion source (INS-PIS) installed on the cyclotron of the Institute for
Nuclear Study of the University of Tokyo, whichis shown in Fig. 3. The dissociator tube is madeof Pyrex and the aperture of the exit channel is
2.2 mm. In this study, 4He gas is used for economical reason. The gas was excited by a 20 MHz RF
electro-magnetic field and flew into the ionizer
through the sextupole magnet whose field converges only He atoms whose spin components
are + 1. Consequently, the intensity of the He
beam in the ionizer becomes higher when sextupole field is supplied than that when not supplied if a significant amount of 2S state atoms
are created. The He+ ion beam is extracted by 8
k V DC voltage and separated from other ionswith a bending magnet next to the ionizer. We
measured the difference of the beam intensities
between when the sextupole field was supplied
and when not supplied but we detected no difference. We consider several reasons why the difference was not detected.
1. Impurities in the He gas quenched the 2S
state created in the tube.
2. The 2S state atoms spontaneously decay to
the ground state by collision with the wall of
the dissociator tube.
3. The 2S state atoms decay to the groundstate by collision with other He atoms.
4. A substantial amount of 2S state atoms are
not produced in the tube.
We have examined these issues. First, the He
gas was passed through a liquid nitrogen trap toremove impurities, but no current difference wasobserved. Second, we used the dissociator tube
with an aperture of 8 mm in diameter to extract
He atoms without colliding on the wall of theaperture. The RF discharge was carried out at
gas pressures of 0.01 Torr to 1 Torr, but nodifference in the current intensity was observed.
Finally, we measured RF power dependence ofthe light of transition from the 2P state to 2S
state, which is shown in Fig. 4. The light intensity increases as the RF power increases, anddoesn't depend on the pressure in the tube. It
seems that the RF power is not enough to create
an appreciable amount of the 2S states. The
quenching of the 2S states due to He-He collisionis, howeve, most probable because the RF powerof 400 W is enough to dissociate a large amountof H2 molecules under the same condition. If it is
the case, the 3He nucleus can be polarized bylaser optical pumping. A DC discharge method
will be examined to find out the best way to
produce the 2S state.

224

T. Fujisawa, et at.

Nucl. Instrum. Methods, 116,2 (1974).

References
S.D. Baker, E.B. Carter, D.O. Findley, L.L. Hatfeld,
G.c. Phillips, N.D. Stockwell, and G.K. Waltters:
Phys. Rev. Lett., 20, 738 (1968).
2) R]. Slobodrian, C. Rioux, ]. Giroux, and R Roy: A.
I.P. Can! Proc., No. 131, 8 (1985).
3) W.E. Burcham, O. Karban, S. Oh, and W.B. Powell:
1)4) F . Laloe, P.]. Nacher, M. Leduc, and L.D. Schearer:
A.I.P. Can! Proc., No. 131, p. 45 (1985).

F.D. Colegrove, L.D. Schearer, and G.K. Walters:
Phys. Rev., 132, 2561 (1963).
6) A. Minoh, T. Fujisawa, Y. Taniguchi, S. Ishii, and K.
Hatanaka: This Report, p. 225.

5)

225
RIKEN Accel. Prog. Rep. 22 (1988)

V-1-15.

Basic Study ofa Polarized 3He Ion Sourceby Laser Optical Pumping. II

A. Minoh, T. Fujisawa, Y. Taniguchi, S. Ishii, and K. Hatanaka
solid-state lasers provide us with more convenient laser materials. Nd 3+ ion (4F3/2~4Il1/2 transition) in proper host crystal can be laser action in
the 1,um infrared region. 2) Two materials with alaser line at 1,083 nm have been known; one ofthem is yttrium aluminum perovskite (YAPP)
and another is lanthanum neodymium hexaaluminate (LNA).4)
At the start of the design and development of alaser system for 3He optical pumping, we measured the fluorescence yield of the YAP laser rod
excited with a GaAIAs diode laser of 800 nm(Sony Co. Ltd. SLD-301 V) and an Ar+ laser of

We study the production of nuclear-polalized
3He atoms for an accelerator ion source by alaser optical pumping method. A stable laser
system for the optical pumping of 3He 2S-2Ptransition of 1,083 nm has not been established in
the world. A color-center laser using F 2 + centers
in NaF was employed by Nacher, et at. ll However it should be operated at liquid-nitrogentemperature and its colored crystal should be
replaced periodically. The YAG laser is a very
excellent and technically established laser system, but the wavelength of laser line is slightly
shorter than 1,083 nm. Recent development of

880

900

940 \r----~~-"""O':----:-l~b8~0--1-1.L.100~I(~nm)

920

Fig. 1. Fluorescence spectrum of Nd3+: YAP excited with the diode laser. The spectral
response of photomultiplier R-318 is not corrected.

400

500

600

700

Fig. 2. Absorption spectrum for Nd 3 +: YAP.

800 (nm)226

A. Minoh, et al.

514.5 nm (NEC GLS-3200). The YAP rod is cylindrical, 2 mm in diameter and 12 mm in length. A
beam from the diode laser was collimated withcollected lenses and longitudinally focused into
the YAP rod. The emitted fluorescence wasanalyzed with a 50-cm grating spectrometer anddetected with a photomultiplier (Hamamatu
Photonix R318).
The observed fluorescence spectrum shown in
Fig. 1 exhibits two strong transition. One is agroup from 900 to 930 nm and another is thegroup from 1,050 to 1,100 nm. The intensity of thefluorescence peaks around 910 nm excited with
the Ar+ laser was four times larger than thatwith the diode laser. The power of a focused Ar+
laser beam on the YAP rod was found to be 3.5mW with a SCIENTIC Model-361 power meter.
The total output power of the diode laser isknown to be 70 mW from the laser operation
current and the internal monitor photodiode.
An unpolarized absorption spectrum of N d 3 +:YAP measured wi th a spectrophotometer(HIT ACHI 320) is shown in Fig. 2, which showsthat the absorption coefficient at 514.5 nm is thesame as that at 800 nm, and the quantum efficiency of fluorescence from N d 3 +: YAP is notvaried appreciably by changing the excitation
wavelength from 514.5 nm to 800 nm. Thus, weconclude that the power focused on the YAP rod
was only a very small fraction of the total output
power from the diode laser. Since the diode laser
output beam had an asymmetric and large divergence angle, the collimation lenses were notcapable of transferring the diode laser output
beam into the YAP rod.
The laser 1,083 nm output power strongly
depend on the power and characters of the pumping laser beam. The results indicate that the Ar+
laser is excellent for a pumping laser. When thediode laser is used as a pumping laser, a beamcollimation system is indispensable to obtain thesame qualities as the Ar+ laser.
References
1) P.J. Nacher, M. Leduc, G. Trence, and F. Laloe: ].
Phys. Lett., 43, L-525 (1982).
2) Kh. S. Bagdasarov, A.A. Kaminskii, and G.!. Rogov:
Sov. Phys. Dokl., 14, 346 (1969).
3) G.A. Massey and J.M. Yarborough: Appl. Phys. Lett.,
18, 576 (1971).
4) L.D. Schearer, M. Leduc, D. Vivien, A.M. Lejus, and
J. Thery: IEEE]. Quantum Electron. , QE-22, 713(1986) .

227
RIKEN Accel. Prog. Rep. 22 (1988)

V-2.

Synchrotron Radiation Source Development
1.

A Preliminary Design of the 8 GeV Chasman-Green Lattice
R. N agaoka, H. Tanaka, K. Yoshida, K. Tsumaki, and M. Hara

A lattice design for the light-source storage
ring is presented. Following our previous workon the 6 GeV Chasman-Green (CG) lattice,l) we
reinvestigated the CG lattice by increasing theenergy from 6 to 8 GeV. Keeping the main performance of the machine the same as in the 6
Ge V case, we confined ourselves to design amachine smaller than 1,500 m in circumference:
The increase of energy would be preferable tothe "users," but it generally results in having alarger ring since the emittance is proportional to
the square of energy: ex OC E2. (j3, where E is thebeam energy and 8 is the bending angle. A simple
scaling from the 6 GeV result causes the numberof cells to shift from 36 of the 6 Ge V ring up tonearly 44 to preserve the same emittance value(---'-'8 nmrad). Considering the beam dynamics in alow-emittance machine to be quite sensitive tothe symmetry of the ring, we chose the nearest"good" number, 48, as the number of cells. The
minimum achievable emittance then becomes~ l. 7 nmrad. Associated with the change ofenergy, the strength of dipole field is loweredfrom 0.8 to 0.6 T to lighten the load of the rf
system. A rough estimate gives 25% reduction in
the accelerating power.
The basic magnet arrangement of the lattice isunaltered: 2 dipoles (rectangular type), 10 quadrupoles, and 7 sextupoles in a single cell. The
length of a free straight section is taken to be 6.5
m. In the present study, quadrupole and sextupole fields are limited to the following values
to ensure the technical validity of 10- 4 orderprecision of the field strength: I dEyI ds I :::;; 16T 1m, and I d 2l3y1 ds 2 I :::;; 300 T 1m 2, respectively.
These threshold values are expected to be raisedin future. Since the field strength basically scales
linearly with energy, some of the magnets aredesigned to be thicker. In particular, the focusing
quadrupole in the triplet has 110 cm in thickness
to allow the low beta mode (see below). Also,
spacing are taken care of to install chromaticity
correcting sextupoles thicker than the previous

Table 1. Major parameters of the 8 GeV ChasmanGreen lattice considered in this study.
Parameter list of the 8 Ge V CG lattice
Circumference = 1,478.4 m
No. of cells = 48
Dipole field = 0.6 T
Length of free straight section = 6.5 m
Revolution period=4 .9 flS
Energy spread O"p = 1. 02 X 10- 3
Maximum dispersion=0.38 m
High
beta
mode
Natural emittance(horizontal) [nm • rad]Betatron tune
Horizontal
VerticalNatural chromaticity
Horizontal
VerticalHorizontal beta
at straight section [m]Hybrid mode
type A type B

7.4

4.9

7.5

40.22
17.16

51. 75
19.82

45.22
15.16

-69.8 -126.1-34.1 - 42.6

-86.4
-33.4

20.37

23.11
1.13

32.67
4.08

value of 40 cm. Spacing on both sides of dipoles
are kept longer than a meter (113 cm) to accomodate the bump magnet for the injection andcrotches of the vacuum system. The resulting cell
length is 30.8 m and the circumference is 1 ,478.4m.
In addition to the "high beta" mode studied forthe 6 Ge V ring, the so-called "hybrid" mode isdesigned and examined in the present study. The
hybrid mode, which is also employed by the
ESRF for their 6 GeV CG lattice,2) is an optics inwhich the horizontal betatron function at thestraight section is alternatively varied from high("-'20 m) to low (~1 m). Undulators will be installed at high beta sections, while wigglers andrf cavities will be placed at low beta sections. In
the hybrid mode, the 48-cell ring possesses thesuperperiodicity of 24 at the maximum. We present here, three optics considered in the given

228
50 , - -- - - - , - - - - - - - . -- -- - , - - ---,-- ---,-- - - , . - , 2.0

High Beta ModeHigh Beta Mode
I. G

40

c
o

'"
~

1.2

40 .. _--------,-- ---- --- -- ------------ -- --- -- -

E

..s

6

>-

0 .8

20

o \:;0 ---',,---~~--+.;---~~-"*"
25;--~
30 0 .0-60(a)High beta mode.

(a)

- 30

0

X [m mJ

30

60

High beta mode.

6 0 . - - . - - , - , , - , - - , - - , - - ,- - ,- - , - ,Hybrid Mode (type A)
40

Hybrid Mode (type A)
I.G

c

o

'"
1.2 ~
6
20

O.S

E 40

-----------r-----------r-----------1-- ---------T----------

..s
>-

I

,

•

,

:

:

:

:

..
,
..:
,
.
,
.
,
-----1------- -----,---- -----:- ---- ----1--- --- -- --:

:

:

,

•

,

I

,

•

,

I

,

,,

0 .4

10

"

20 -

0_

(b)

Hybrid mode (type A).

90

-60

-30

X lm ml

0

30

60

30

60

(b) Hybrid (type A).
60

Hybrid Mode (type B)

Hybrid Mode (type B)
I.G

40

c
o
30

1.2

~

6
0.8

0.4

10

40

E

..s
>-

20

- 60

-30

0

X lmm l(c)

Hybrid mode (type B).

Fig. 1. Betatron and dispersion functions over a superperiodic cell.

magnet arrangement: One high beta mode andtwo hybrid modes. The optics functions are displayed in Fig. 1, and major parameters are listed
in Table 1. In all three optics, working points are
selected so that tunes per superperiodic cell stayaway from 1st- and 3rd-order resonances of the
sextupoles, and total tunes of the ring avoid(c) Hybrid (type B).
Fig. 2. Dynamic aperture of the ideal lattice. Triangles
indicate the dynamic aperture without harmonic correction, and dark squares represent the dynamic aperture with correction.

nearby non-structural low-order resonances.
Type A of the hybrid mode, which more or lessresembles the optics of the ESRF, is rather
strongly focused and has a local mirror symme-

229

R. Nagaoka, et al.

try at the midst of an achromatic arc. Type B is_a much more detuned optics in which the horizontal tune per superperiodic cell is intentionallylowered below 2 to reduce the influence of thestrong integer resonance driven by the sextupoles.
As in the 6 GeV CG lattice, two "harmonic"
sextupoles are placed on each side of an arc toenlarge the otherwise insufficiently small
dynamic aperture. Harmonic sextupoles are
optimized by using the computer code CATS. 3)
The resultant dynamic aperture of an ideal
machine is shown in Fig. 2 for the three optics.
Although the dynamic apertures of the hybrid
modes are calculated at the high beta section as
well, they are found to be smaller, especially intype A, than that of the high beta optics. Indeed,
despite the use of four families of harmonic
sextupoles in the hybrid modes, the optimization
was not as effective and transparent as in thehigh beta case. We found that large amplitude
motions in the hybrid optics are apt to beaffected by higher-order resonances of the sextupoles (6th order in the case of type A), which ispresumably due to the reduction of thesymmetry.4) Tune shifts with amplitude and with
momentum deviation are shown in Figs. 3 and 4,
respectively, for type A.
Tracking with various errors in the ring aswell as the correction of closed-orbit distortion(COD) is done by using RACETRACK.S) Table 2
lists the kinds of errors included. The COD correction is done with 8 monitors and 6 horizontal(vertical) correctors in a cell. Figure 5 illustrates
the magnitude of the dynamic aperture as afunction of residual COD in the ring. One finds

Hybrid (type A)
~

2.164

~

2.162

.•

::J

en
Qj
c:

2.160

I-

2.158

~

::J

~

J

iii

g 2.156
N

~

J:

2.154

o

10
X

30

20

40

[mmJ negative

Fig. 3. Amplitude dependence of the betatron tune.
Calculation is performed for the hybrid mode (type A)
measuring the tune shift per superperiodic cell.
Hybrid (type A)

0.2• dnux
0

0.1

:c
II)

CI)

0.0

c:

~

000 ~

.4

-0.1

-0.2
-2

••

dnuy _..- --.. .
••

o

-1

•

•
2

dp/p (%)

Fig. 4. Momentum dependence of the betatron tunes
after chromaticity correction. Filled circles denotehorizontal, and open circles represent vertical tune
shifts. Calculation is performed for the hybrid mode
(type A).

that the dynamic aperture cannot be fully restored even in the limit of zero rms of COD. The
optimization of the correction system and thetracking calculation in view of beam injection

Table 2. Kinds of errors included in the tracking calculation and in the COD
correction.
Distribution: Gaussian
Dipole:-Field error L1 B I B:
- Tilt error L1 8:(B) Quadrupole:- Field error L1 B' I B':- Misalignment error:- Tilt error L1 8:(C) Sextupole:-Field error L1 B" I B":- Misalignment error:- Tilt error L1 8:

0.5 mrad(A)

5 X 10- 4
0.5 mrad(dipole)(dipole)5 X 10- 4
0.2 mm
0.5 mrad(normal quad)(dipole)(skew quad)

5 X 10- 4
0.2 mm(normal sext.)(dipole)(normal quad)(skew quad)(skew sext.)

230

R. N agaoka, et at.

Hybrid (type A):

Ideal X = 30.1 [mm]Hybrid (type B):

30+-----------------~

Ideal X

= 49.8 [mm]30ta~----------------~

~
.~

iii
~

..s
10+----------L----~--~

a

><

"Ill

20 - j . I I I I 1 - ; a ; - - - - - - - - - - - - - - - - - - - j

10+-------L-----------~

a><O+-~~~~~-.~~~

o

2

(a)

3

4

(codH}rms

[mm]

5

6

Hybrid (type A).

O+-~~_.~.-~~~~_j

o

2

3

4

5

6

(codH}rms [mm](b)Hybrid (type B).

Fig. 5. Dependence of the dynamic aperture on the magnitude of residual COD. The dynamic aperture is calculated
at 1% coupling for several rings with errors (different random seeds).

are currently carried out.
We have designed the 8 GeV CG lattice composed of 48 cells and examined their properties.
In brief, we found that there do exist many good
low-emittance optics with moderate focusing inboth high beta and hybrid modes, owing to thesmallness of the bending angle f). We havenoticed, however, that the smallness of f) is notadvantageous in having a large dynamic aperture: The suppressed dispersion function in thearc brings about stronger sextupoles for thechromaticity correction leading to the enhancement of the unwanted resonances. We actuallychecked this trend by designing rings composedof fewer cells. A geometrical problem of spacing

between each photon beam line may also be
serious with a too small f). With these positive
and negative aspects of the 48 cell ring, further
investigation is yet to be done to obtain the
optimal 8 Ge V light source storage ring.
References
1) H. Tanaka, R. Nagaoka, and M. Hara: RIKEN
Aeeel. Prog. Rep., 21, 225 (1987).
2) The Red Book Draft B, ESRF (1987).
3) R. Nagaoka, H. Tanaka, K. Yoshida, K. Tsumaki,
and M. Hara: This Report, p. 248.
4) R. N agaoka, K. Yoshida, H. Tanaka, K. Tsumaki,
and M. Hara: This Report, p. 242.
5) A. Wrulich: DESY Rep., 84·026 (1984).

231
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-2.

Correction of the Closed Orbit Distortion (COD)
for an 8 GeV Storage Ring (1)H. Tanaka, R. N agaoka, K. Tsumaki, K. Yoshida, and M. Hara
The COD correction is crucial for a lowemittance storage ring which is very sensitive forelectromagnetic errors. The COD at a sextupole
magnet makes a circulating particle feel a additional quadrupole component corresponding to
its amplitude, inducing a tuneshift at every sextupole around the ring. That is, the COD breaks
a local phase advance among the sextupolesarranged well along the ring to suppress theresonance driving terms induced by themselves.
The COD also distorts the workpoint that has
been carefully optimized to avoid the fatal resonances, and a beam stay clear region is markedly
reduced consequently. To minimize these breaks
and to recover the wide beam stay clear region,
the COD should be corrected around the ring asprecisely as possible. In the literature, a COD
correction system of a 48 cell-8 GeV Chasman
Green (CG) lattice!} has been investigated.
In Table 1, a condition of random errors isshown. The value for each error represents thevariance (0-) of a special Gaussian distribution
trunca ted at 20-.
To simulate a COD correction, we use"RACETRACK"2) in which two kinds of correction methods are prepared: "Local Bump"3) (LB)and "Most Effective Corrector"4) (MEC) methods. The MEC and the LB can be iteratively usedwith arbitrary combination. In addition, a concept of dipole random error scaling was adopted
to make a simulation easy. The final error condition (scale factor = 1) can be approached stepTable 2.

Monitorl)
1
2
3
4
5
6

at sextupoleat quadrupoleat quadrupoleat sextupoleat sextupoleat sextupole

1) See Fig. 1.

Condition of random errors.

... Bending magnet field error (dB / B) 5.0 X 10- 4... Bending magnet tilt error
5.0 X 10- 4 rad... Misalignment at Q magnet... Q magnet gradient error (dB' / B')... Q magnet tilt error

2.0 X 10- 4 m
5.0 X 10- 4
5.0 X 10- 4 rad... Misalignment at sextupole magnet 2.0 X 10- 4 m.. ·Sextupole magnet tilt error
5.0 X 10- 4 rad.. ·Sextupole magnet gradient error(dBI / B")
5.0 X 10- 4

wise by taking serial scale factors like 0.3, 0.5,

o.7, and 1.0. A maximum corrector strength
was limited to 2 mrad and a minimum phaseadvance for the LB between two correctors was
defined 0 . 075 in the horizontal plane and 0 . 050 in
the vertical plane.
Following six parameters were used to estimate a system performance: a maximum corrector strength, a convergence of COD, the recovery
ratio of a dynamic aperture, a final residual COD
value, a number of elements in the correction
system, and the influences on the design of hardware. In respect of a dynamic aperture, thedynamic aperture at the low X - Y coupling (0.01)
was used. The effects of difference among COD
correction schemes on the parameters were also
considered.
The COD correction system has so manydegrees of freedom that we can not treat all

Case study list of investigation of the COD correction system.
Number ofmachines

Arrangement

Case

Table 1.

Number ofmonitors

Corrector\)
B
B
A
A
A
C

7
5
5
5
5
6

336 (7/ cell)
480 (lO/ cell)
480 (l 0/ cell)
336 (7/ cell)
336 (7/ cell)
336 (7/ cell)

Number ofcorrectors
Horizontal

Vertical

288 (6/ cell)
288 (6/ cell)432 (9/ cell)432 (9/ cell)432 (9/ cell)
144 (3/ cell)

288 (6/ cell)
288 (6/ cell)432 (9/ cell)432 (9/cell)432 (9/ceU)
192 (4/cell)

,

("' \

,

!

,

iii:

,

,

20

n

E3

~~~~~~~ E3

,

E3

,

i "', \

,
1.6

'],.,
]

V

V

B

BV

V

B B B V

V

V V

a B

V V

a

a

a

a

v v

a a

v v

V

V

B

V

B V

v

a a av

EJ

0 ••

V V

aa

v v

\ / --

I

0 .8

B

v

a

cS

av

V

av

B

Va

--"·~~·fr--+-

(c)

B

B V

B

a

Fig. 1.

V

V

a

2)

1)

000
NNN

00
NN

I
o

~

0
N

o
N

MM

MHM

Quadrupole magnet

Sextupole magnet

000

VerticalMON : Monitor

corrector

Horizontal corrector

H

NNN

V

000
NNN

0000

MMM

NN

00

·~-+-11

arrangement

NN

00

NNNN

MMMM

Bending magnet

N

0

M M

H

--~~

Quadrupole _ oriented

MMM

MM

MM

arrangement

MMM

MM

N N

N

0

o 0
N N

0 0

o 0
N N

W~-M M M

NN

00

MMMM

NNN

000

--~IDJ-~".~~--+-~~.~~'-.~--

Sextupole _ oriented

Arrangement of monitor

Arrangement of monitors and correctors.

v~~·fr--

B--~~~·~r-+-~r~·~~~t~~f--

v v

a B

a

V V

B

V

--~r,am·~-+-~~

(B)

,

iii

,

n n ~~~~~~~ n

Arrangement of corrector

(A)

,

\
"p.\ /~n~'/\.> /\ r~n~
I~j" I

'0

"[

~

~

~

.?l

;:0:;"

~

::s

~

p:=

~
~
~

233

H. Tanaka, et al.

parameters simultaneously. We intentionaly
divide the investigation into two parts: one isarrangement of monitors and the other is that ofcorrectors. All case studies are listed in Table 2,
and all arrangements of monitors and correctors
are shown in Fig. 1.
The arrangement of monitors is categorized
into two: one is based on the correction of
misalignment of the quadrupoles which mainly
cause COD, and the other is based on the correction of the tuneshift induced by the sextupoles.
Two arrangements were compared with eachother under two conditions: the same corrector
arrangement (Case '1 and Case 2 in Table 2) andthe same ratio of the number of monitors andcorrectors (Case 1 and Case 3 in Table 2). In thesecomparisons, no appreciable difference wasfound for a maximum corrector strength, a convergence of COD, the recovery ratio of a
dynamic aperture, and a final residual COD
value. This result is due partly to the fact thatthe sextupoles are located very closely to thequadrupoles in a CG lattice and both arrangements give almost the same COD pattern at the
sextupoles through the COD correction. In
respect of monitors, sextupole-oriented arrangement has less number of monitors thanquadrupole-oriented one. The less number ofmonitors makes simpler design of a vacuum
chamber because of their setting needs highaccuracy. Therefore, sextupole-oriented arrangement has advantages in designing hardware. As
a result, we found that the sextupole-oriented
arrangement is better than the quadrupoleoriented one; this result is always right in a CG
lattice under the assumption that the sextupole
optimization (including location of the sextupoles) is not so different among all candidates
for CG lattices.
The arrangement of correctors was investigated on the basis of sextupole-oriented arrangement of monitors with three kinds of arrangement of correctors shown in Fig. 1; as the casestudies, Case 1, Case 4, and Case 6 in Table 2.
The calculation results are shown in Figs. 2
and 3. A difference appears in the convergenceof COD and the maximum corrector strength.
The maximum corrector strength increases withincreasing number of correctors. The convergence of COD is improved with increasing number of correctors and seems to be leveled off
when the number of correctors exceeds those inCase 1. This result will be explained as follows.
The increase (or decrease) in the number ofcorrectors means the increase (or decrease) in the
degree of freedom for the correction; therefore, aproper increase (or decrease) leads to quick (orslow) convergency of the COD and the small (orlarge) final residual COD value. An excessive
increase (or decrease), on the other hand, reduces(or promotes) the phase advance among correctors and leads to not only quick (very slow)
convergency and the small (or large) final residual COD value but also a strong (weak) corrector
strength especially on the LB mathod adopted in"RACETRACK." The convergence of COD represents how easy COD can be corrected. In addition' since every sextupole includes only one kindof corrector (horizontal or vertical), Case 1 andCase 6 have an advantage in designing a sex-

:;

2.0

III

c

~

!

average value

1.5

.c:
.j.I

0 . 95

1.0

tTl

c::

0.76

Q)
~

+I

0.5

0)

0.36

><

III

:E

0.0
4
decreasing Correctors

Case
Ij.j

0
~
Q)

.Q

7'

70

0

50

+I
0

40

c::

Q)
~
~

30

.,.j
.j.I

0
0

20

0

10

U

o

Ei

c::='

0

III
~
Q)

+I
H

numberC : average value

60

c::

~= >

56 . 3

.,.j

0

20.6

4

•

15.3

1

6

decreasing c orrectors ==>Casenumber

0.20
C
0
0--

u!

0.15

t

I/)

CQI='

0.10

~ >
rz.

0.05

~

•..

.-t
.-till.,.j: average CODx
average CODy•

: COD xA

: CODy0.00

4 1 6
decrea sing co rrecto rs ==>CasenumberFig. 2. Dependence of the corrector arrangement on the
maximum corrector strength (upper diagram), the COD
convergence (middle diagram), and the final residual
COD value (lower diagram).

H. Tanaka, et at.

234
30• Case4D Casel-

25
Do.

20

i

~~li ~QcK~8

15

1IKo. &•I><

K Case6-

I

K,

K

.
.. • R
K

11

10

K

D
D

i} •

..

I

D

•

5

o
rms

o

1

value

2
of

3
residual

5

4

COD

(mm)

Fig. 3. Dependence of the dynamic aperture behavior on
the corrector arrangement. X - represents the dynamic
aperture of a tracking initial phase = 180 deg. Tracking
condition, turn no. = 500 at the center of high f3 straightsection; X - Y coupling factor = 0.01.

50-70%; anda final residual COD value is < 0.2 mm.
An important result is that the number ofcorrectors more than 6 per cell in each plain is
not effective for the COD correction. We can
avoid installing two kinds of correctors in one
sextupole and this is much preferable to designof a sextupole.
On the basis of the present study, a further
investigation of the arrangement of monitors andcorrectors should be carried out with more random seeds (more number of machines) and withmore kinds of arrangements. We hope to optimize not only the correction system for the
global COD but also the correction system for the
local COD at the long straight section in moredetail in the near future.

References
tupole. Thus, Case 1 is found to be the best,
because Case 4 has a fatal disadvantage indesigning a sextupole and Case 6 also has a fatal
disadvantage in the COD convergence. The final
performance of the COD correction system is:
the recovery ratio of a dynamic aperture is1) R. Nagaoka, H. Tanaka, K. Yoshida, K. Tsumaki,
and M. Hara: This Report, p. 227.
2) A. Wrulich: DESY Rep., 84-026 (1984).
3) H. Fukuma: KEK Accel. Semin.-OHO'88, 1II-3 (1988).
4) E. Gianfelice and R. Giannini: CERN I PS, 85- 42 (LEA)(1985).

235
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-3.

Correction of the Closed Orbit Distortion (COD)
for an 8 GeV Storage Ring (2)H. Tanaka, R. N agaoka, K. Yoshida, K. Tsumaki, and M. Hara
For the arrangement preliminarily optimizedin the previous COD correction,l) following two
detail investigations were performed:(1) Effects of a monitor and a corrector error
to the performance of the COD correction system.
(2) Effects of adjustment of a workpoint to
the recovery of a dynamic aperture.
The calculation was executed with
"RACETRACK"2).
A monitor error results from a misalignmentof a monitor and inaccuracy of a monitor detection signal. It can be regarded a kind of displacement error at a monitor. Effects of a monitor
error were investigated with five values between

0.1 mm and 0 .5 mm, which are the same order of
the tolerance of the Advanced Light Source
Project in Lawrence Berkeley Laboratory.3)
The calculation result of the final residual
COD value is shown as a function of a monitor
error in Fig. 1. The final residual COD simply
increases with increasing the value of a monitor
error and is beyond 0.2 mm at 0.3 mm error.
Figure 2 shows the correlation between adynamic aperture and a monitor error. Withinsmaller errors than O. 3 mm, the change in the
dynamic aperture is slight, but between 0.3 and0.4 mm, it becomes irregular and large. We canfind the monitor error beyond 0.3 mm, the dy0.3~----r---~----~----~

0.4
•
Q)

::s

!

0 .3

e~ 0a

0 .2

.-I

III

>
al

U

.-l

III 11-1
c:: 0

0. 1

.r!
~

:

CODx

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

~~
l---"'

0.0
0.0

~

~

::s

~~

CODy

~

!

0 .2 -+----+---.........----+---4'

A:

CODy

ala

eo
~u

v"

.

0 . 1 ..-- - t - --lil=--= t - - -...

.-l 11-1~ 0~

O . O +-----~--~-----+----~

0.1

0 .2

0.3

0.4

error

(rom)

0.5

0.0

0 .5

Corrector

Fig. 1. Dependence of a final residual COD on a monitor
error.

20

errors1.0().!rad)Fig. 3. Dependence of a final residual COD on a corrector error.
24

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

C

Casel -•

Case2-

6

Case3-

I

><

CODx

.-I.-

....

Monitori.:Q).,...A

22

i

20

I

18

><

10

1:1

Casel-•••

Case2Case3Case4-

16o +-~,-~~~~~~~~~~

0.0

0. 1

0.2

Monitor

0.3

0 .4

errors

0.5

0.6

(rom)

Fig. 2. Correlation between a dynamic aperture and amonitor error. X - represents the dynamic aperture ofa tracking initial phase = 180 deg. Tracking condition:
The tracking turn number is 500. The calculating point
is at the center of a high f3 straight section and XY coupling is O. 01 .

14
0.0

0.2

Corrector

0.4

0 .6

errors0. 8

l.0).!rad)Fig. 4. Correlation between a dynamic aperture and acorrector error. X - represents the dynamic aperture of
tracking initial phase = 180 deg. Tracking condition:
The tracking turn number is 500. The calculating point
is at the center of high f3 straight section and X- Y
coupling is 0.01.

236

H. Tanaka, et al.
20

C monitor error +corrector error
normal random
errors

U
'M~

~ ~

+

c>t

1:)01
1-1
.... :J
",4J
U
'M

)(

only normal random•

ideal (no error)

10

~

P.

4J
1-1 "'
01>

O ~~~~~~~~-r~-4 0 - 30 - 20 -1 0

Horizontal

0

dynamic

10

20

30

aperture(mm)Fig. 5. Comparison of dynamic apertures for threecases. Tracking condition: The tracking turn number is500. The calculating point is at the center of high f3
straight section.

namic aperture is no longer anticipated. Therefore,taking some allowance, we adopted 0.2 mm as
the tentative tolerance of the monitor error.

A corrector error results from the defects in a
power supply and in a magnet. It can be regarded
as a kind of field error at a corrector. On thedesign of a magnet, we may suppose about
0.01% of errors of a full range (1 - 2 mrad).
Effects of a corrector error were investigatedwith the three values (0.1, 0.5, and 1. 0 ,urad).
The final residual COD value calculated as afunction of a corrector error (Fig. 3) is almost
constant within errors smaller than 0.5 ,urad,and beyond 0.5 ,urad its scattering and averagevalue become large. The correlation between adynamic aperture and a corrector error is shownin Fig. 4. The dynamic aperture is almost constant within errors smaller than 1. 0 ,urad. Considering that the scattering of the final residual
COD value becomes large at the corrector errorof 1.0 ,urad and taking some allowance, we
adopted 0.5 ,urad as the tentative tolerance of theTable 1. Comparison of dynamic aperture to find the level of the COD correction. Tracking condition:
The tracking turn number is 500. The calculating point is at the center of high f3 straight section.
Randomseed

Case 1 (X, Y)

Dynamic aperture (mm)Case 2 (X, Y)
Case 3 (X, Y)

Case 3
Case 2

X- Y coupling = 0.01, Initial phase = 0.0 (deg), Ideal dynamic aperture (- 26.22, 1. 79)

1
2
3
4

(17.93,(17.31,(16.85,(13.72,(19.57, 1.36)(21. 29, 1.48)(19.65, 1.34)(21.37, 1.45)(17.38, 1.10)(14.70, 0.96)(17.33, 1.19)(12.84,0.86)

1.11)
1. 05)
1.16)
0.95)

0.97
0.85
1.03
0.94

X- Y coupling= 0.01, Initial phase = 180 (deg), Ideal dynamic aperture (- 30.13, 2.05)
1
2
3
4(21.76,(22.93,(23 .63,(20.98,

1. 51)
1.59)
1.62)
1.42)

(20.82,(21 .29,(20.36,(15.58,

1.39)
1.30)
1.40)
1.07)

(22 .54,(17.43,(18.70,(14 .01,

1.42)
1.14)
1.29)
0.94)

1.08
0.82
0.92
0.90

Case 1: the only quadrupole gradient error.
Case 2: the gradient error+the sextupole misalignment error.
Case 3: normal random errors with the COD correction.
X, Y represent horizontal, vertical dynamic aperture.
XY Coupling=O.OI, Initial phase= O.O (deg.)
Ideal dynamic aperture(26 . 22, 1.79)
Case

Dynamic aperture (mm)

( X ,
A
B
C
D

E
F

G
H
I
0 . 66 0 . 75
X
X: Hor i zonta 1 fra ct i ona 1 tune
Y: lJertical fractional tune

1.0

J
K
L

Y)

(19.57, 1. 36)(17 .93, 1. 11)(17.38, 1.10)(21.29, 1.48)(17.31, 1.05)(14.70, 0.96)(19.65, 1.34)(16.85, 1. 16)(17.33, 1. 19)(21. 37, 1.45)(13 . 72,0 . 95)(1 2.84, 0 .86)

Ideal fracti onal tune
(0.749958, 0.819906)
Fractional tune
(

Nx

,

(0. 751511,(0.782490,(0 .739174,(0 .749591,(0.711696,(0. 735046,(0 . 751660,(0 .738237,(0 . 737156,(0 . 756371,(0 . 738814,(0 . 726100,

Ny)0.824432)
0 . 790325)
0 .790349)
0 .815654)
0.824438)
0 .800265)
0.818021)
0.836594)
0.837636)
0 .818884)
0.819629)
0.834027)

Fig. 6. For 12 kinds of practical rings where the COD is corrected, the tunes are plotted in the left diagram and the tunes
and the dynamic apertures are listed in the right table.

H. Tanaka, et al.

corrector error.
Assuming a monitor error and a sextupole
misalignment are independent of each other, we
calculated a dynamic aperture for the ring including the normal random errors,l) the monitor
error of 0.2 mm, and the corrector error of 0.5,urad corresponding to the tolerance. Figure 5
shows the calculation result together with othertwo cases; the case including the only normal
random errors and no error (the ideal case),indicating that the dynamic aperture is largely
reduced at a low X- Y coupling compared withthat at a high X- Y coupling and that, at worst,
the dynamic aperture of a X- Y coupling of 0.01
is reduced to one third of the ideal one, about 10
mm. Compared with the case including only
normal random errors, the reduction is few
dozens percent larger.
To improve the recovery ratio of the dynamic
aperture, we investigated its behavior in detail.
For the following three cases, dynamic apertures
were calculated to investigate the level of the
COD correction. Case 1 includes only the quadrupole gradient error (COD = O.O), Case 2
includes the gradient error and the sextupole
misalignment error (COD=O.O), and Case 3
includes the normal random errors and the COD
correction. The dynamic aperture reduction inCase 1 and Case 2 represents the contributions ofphase advance breaks, which can not be compensated by the COD correction. Table 1 comparesthe dynamic apertures among three cases. The
dynamic aperture in Case 1 is reduced to twothird of the ideal one. The dynamic aperture ofCase 2 is reduced to one second of the ideal one,which almost corresponds to the dynamic aper-

Table 2. Effect of the adjustment of a workpoint on therecovery of a dynamic aperture.
X-Y Coupling=O.01, Initial phase = O.O (deg.)
Fractional tune is adjusted to Ideal Fractional Tune
(Nx: 0.749958, Ny: 0.819906)

Dynamic aperture (mm)(X, Y)

Case before correction
B
E
H
K
F
I
L

(17.93, 1. 11)(17.31, 1. 05)(16.85,1.16)(13.72, 0.95)(14.70,0.96)(17.33, 1.19)(12.84, 0.86)

After correction(15.59,(18.16,(15.20,(17.93,(17.62,(16.76,( 8.71,

1.03)
1.14)
1.05)
1. 23)
1.18)
1.12)
0.59)

Effect++Effect+ means that the tune adjustment is effective.
Effect - means that the tune adjustment is ineffective.

237

ture of Case 3. This means that the dynamic
aperture is no longer improved by the COD correction. We can find that the level of the COD
correction achieving the final residual COD of
O. 1-0.20 mm has already been sufficient.
To investigate correlation between a global
tuneshift and the reduction in the dynamic aperture, the dynamic apertures were plotted on atune-diagram as shown in Fig. 6, which suggeststhat the reduction in the dynamic aperture does
not greatly depend on the workpoint, because thering whose workpoint is nearest to the third
integer resonance has a large dynamic aperture.
To confirm this suggestion, the workpoints wererecovered to the ideal point by the COD correction and the dynamic aperture was calculated forseven rings; Table 2 shows results. In half of therings, the reduction of dynamic aperture is improved by adjusting the workpoint. In remaining
half, on the contrary, the dynamic aperture ismore reduced by adjustment. These results indicate that the reduction in the dynamic aperture
does not correlate closely with the shift of theworkpoint. It is also expected that the breaks ofthe local phase advance is dominant in the reduction in the dynamic aperture.
Since the improvement in the COD correction
and the recovery of the workpoint are not effective to enlarge the dynamic aperture, all we cando is to take the following two, if necessary, forthe stable operation, a dynamic aperture larger
than what we can get now. One is to protect thering from all kinds of errors more severely; thismeans that the tolerance of each error should be
reduced and probably leads to the difficulty inalignment and in hardware design. The other is
to find an optics more tough to errors, which
probably gives rise to a large emittance.
With respect to the tolerance of a monitor anda corrector error, extensive case studies shouldbe performed to determine the tolerance, and willbe tried at the next step.
The minimum required dynamic aperture
should be analyzed from the viewpoint of theinjection efficiency for the ring including thepractical errors with the COD correction as soon
as possible. The proper feedback must be taken
into the design of a storage ring lattice.
References
1) H. Tanaka, R. Nagaoka, K. Tsumaki, K. Yoshida,
and M. Hara: This Report, p. 23l.
2) A. Wrulich: DESY Rep., 84-026 (1984).
3) 1-2 Ge V synchrotron Radiation Source Conceptual
Design Report- July 1986, PUB·5172 Rev., LBL.

238
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-4.

Effect of Insertion Devices on Beam Dynamics of
8 GeV Light Source Storage Rings

R. N agaoka, K. Yoshida, H. Tanaka, K. Tsumaki, and M. Hara
The study of the effect of insertion devices(IDs) on revoluting particles is very important indesigning light-source dedicated storage rings.
Anticipated effects of the insertion devices are:Breakdown of the original symmetry, distortionof linear optics, and introduction of nonlinear
forces that may lead particles to additional resonances. The purpose of the present study is toestimate the degree of influence in storage rings
operated at an energy region of 8 Ge V. In particular we work with three types of lattice:
Cha~man-Green (CG), Triple Bend Achromat(TBA), and Quadruple Bend Achromat (QBA) to
examine the dependence of the effect on thelattice structure. Numerical calculation relies forthe most part on the extended version of thecomputer code RACETRACK, which is motivated to include the effect of IDs in particle
tracking. 1)
Our analysis initiates from the following analytical expressions of a magnetic field which is
known to be a good approximation for the actual
distribution inside IDs:2)

To find how the field distribution of Eq. 1
affects the betatron motion, equations of motion
in terms of the conventional coordinate system(X{3, Y{3,s) must be derived. This is done in Ref. 3 inthe Hamiltonian formalism by assuming 1 -< kp(p: Radius of curvature in the peak field Bo) andby partially averaging the Hamiltonian over theperiod length:x" = -kx (2k 2p2) (kxx+k x3X 3/ 6+kxky2xy2 / 2)

Bx= k x/ ky • Bo sinhkxX ·sinhky Y ·coskZ (1)- cosks / p. (k/x 2+ k/y 2) / 2

By = Bo coshkxX· coshky Y • coskZ- y 'yksinks / p

Table 1.

withkX2+ky2=k2= (27t / A) 2

(4)

(X, Y,Z) is the fixed frame of reference with Z
as the longitudinal coordinate. The peak field
and the period length of an ID are given by Bo
and A, respectively. The above formulas, whichkeep only the fundamental harmonic of the field
variation in the Z-direction, satisfy the Maxwell
equations. Damping of the field in the Xdirection can be expressed by the replacement kx
~i}(.

(5)

Parameter list of the undulator and the wiggler employed in this study.

Field parameter
Peak field
Period length
No. of period
Total length
Radius of curvaturein the peak field
Vertical wave number
Horizontal wave number
Amplitude of theequilibrium orbit
Photon energyt First harmonic(2)

Bz = - k / kyBo coshkxX ·sinhky Y ·sinkZ (3)Undulator

Wiggler

1.0
0.357
3
166
4.98

25.2
1.5
18
12
2.16

p l (kp)2 (urn)

74.7
2.05 X 10 2
kx=0.2 ky
0.3

17.78
34.23
kx=0.2 ky
46.1

c (keV)

13.5t

64.0

K

Eo (T)A (cm)
Np
L(m)

p (m)
ky (1 1m)

239

R. N agaoka, et at.
50 r --,--, ---r----,--,----,---,---r----,--,---.----" 2 .0

40

1.6

40

1.6

c
o

:§ 30

c
o

:§ 30

</)

.,

1. 2

Q>

~

'"
Q)

6

co

1. 2

~

8

00

20

0 .8

20

0.8

10

0.4

10

0.'

Chasman Green Lattice (eG)
Triple Bend Achroma! crBAl
Circumference ~ 1478.4 m
No. of cells c 48
Dipole field ~ 0.6 T
Length of free straight section = 6.5 m
Emittance (horizontal) '" 7.5 nm'rad
Betatron tune
45.22 (horizontal)
15.16 (vertical)
Horizontal beta at straight section

Circumference", 1477.38 m
No. of cells = 36
Dipole field", 0.6 T
Length of free straight section - 7.0 m
Emittance (horizontal) - 5.8 nm'rad
Betatron tune
48.76 (horizontal)
26.39 (vertical)
Horizontal beta at straight section

32.7 m (high beta)
4.08 m (low beta)

(a)

(b)

20.0 m (high beta)
1.47 m (low beta)

2.0

1.6

c
o

:§ 3 0
1.2

<:)

~

Q)

m

6
20

0.8

10

0 .4

0 .0

Quadruple Bend Achromat (QBA)
Circumference ", 1476.5 m
No . of cells = 38
Dipole field = 0.6 T
Length of free straight section ", 6.5 m
Emittance (horizontal) '" 6.5 nm'rad
Betatron tune
43.20 (horizontal)
17.20 (vertical)
Horizontal beta at straight section

25.0 m (high beta)
7.30 m (low beta)(c)Fig. 1. Optics functions and the major parameters for (a) CG, (b) TBA, and (c) QBA lattice.

y" = -ky (2k 2p2) (kyy +k/y3/ 6+kykx2yx2/ 2)+cosks/ p. kx2xy + x' yksinks / p(6)

In Eqs. 5 and 6, terms up to third order are
retained and we have dropped the subscript {3.
We notice first that, in situations where k x =ix
and I x I < I ky I , the linear effect of ID isequivalent to that of a "pseudo" quadrupolewhich is weakly defocusing in the x direction,and focusing in the y direction. The weak
defocusing in the x direction can be interpreted
as a result of cancellation between the focusing
effect of a dipole and the defocusing effect of amagnetic edge. Maj or nonlinear forces comefrom the octupole-like components as well asfrom the sextupole-like components that vary0+-~-+--~+-~-4--~~~-4

-60

-40

-20

0

0+-~-r~--r-~1_~-+~~

40

20

-60

-40

x (mm)

-20

0

20

40

x (mm)

Fig. 2. Effect of one ID on the dynamic
aperture of the CG lattice. White circles:
Bare lattice. Dark squares: One undulator. White triangles: One wiggler.

(a)40~--~--~----~--~--~

cE
g 20+----r~~--~~--1---~
EE

6+---1-fI--4'r-T+-T--r---t-~one wiggler•

7 wigglers

TVPE:CG>-

9 +---~-4--=+---r--+-~

bare lattice

A

turn# = 200

TVPE:TBA>-

O+-~-r~~~--r-~~~~

-60

-40

2a

a

-20

4a

x (mm)(b)0+-~~-4~-+~-r~+-~-30 -20 -10

0

10

20

30

Fig. 5. Dependence of the dynamic aperture on the numbers of IDs included. (a)Undulators. (b) Wigglers. CG lattice ischosen as an example.

x (mm)

Fig. 3. The same as Fig. 2 for the TBA
lattice.

15~---.----,----.---,

15~--~~--~----~--~

10+----+--~+-~--+--~

TVPE:QBA

E
E
>-

E

O+-~~--~-+--~-r~~

-40

-2 0

o

20

40

x (mm)

Fig. 4. The same as Fig. 2 for the QBA
lattice.

with the position s. These forces may seriously
reduce the dynamic aperture of low-emittancerings in which strong sextupoles are usually
optimized to enlarge the dynamic aperture. 4 )Table 1 lists the parameters of an undulator
and a wiggler employed in this study. The optics
functions and the major parameters characterizing the ring are shown in Fig. 1 for the threelattice. In all three lattice, the "hybrid" mode ischosen in which high beta sections are for theundulators and low beta sections are for the
wigglers. 5 )The degree of linear optics distortion with one

dp/p=O .O%
dp/p=1.1 %A

dp/p=2.2%

TVPE:QBA

E

5+---~~---+----~~~

c

•

>:

turn# = 200

O+-~-+~--r-~-r~~

-40

-20

a

20

40

x (mm)

Fig. 6. Momentum dependence of the
dynamic aperture with one wiggler. QBA
lattice is chosen as an example.

ID in the ring is calculated to be as follows incase of CG lattice: (i) With one undulator, Ll Vx =4.6xIO- 5, Ll vy = 5.8 x 10-\ Llf3x/f3x=- 2.9 x IO - 4 ,and Ll f3y/ f3y = - 4.4 X 10- 3 , (ii) with one wiggler,
Ll Vx = 4.3 X 10- 5 , Ll Vy = 3.4 X 10- 3 , Ll f3x / f3x= - 2.4 X
10- 4 , and Ll f3y / f3y= -2.5 X 10- 2 • The magnitude of

distortion is roughly the same as to the remaining two lattice as well. We find a reasonable
result that the distortion is more pronouncedwith a wiggler due to a smaller p. The degree ofdistortion by a single ID being neverthelesssmall, restoration of the optics is done locally bymatching betatron functions to their originalR. Nagaoka, et at.

values at the midst of an achromatic arc andmatching their derivatives to zeros at the centerof IDs. By this way, linear optics is unaffected in
the cells without IDs. Quadrupole triplets on bothside of ID are used for this readjustment. Twoquadrupoles are used for the betatron matching,
and the remaining one is adjusted to keep thetune shifts minimal. Numerical changes requiredfor quadrupole strength are mostly within few
percent and small.
Effects of nonlinear fields on the dynamic
apertures are examined in Figs. 2-6. The tracking calculation with IDs is performed in RACETRACK by dividing ID into small pieces thereby
incorporating the nonlinear forces as kicks
according to Eqs. 5 and 6, up to fourth order inamplitudes. What can be noticed from the figuresare: (i) Reduction in the dynamic aperture ismore pronounced with an undulator than awiggler. This is plausible since, as seen in Eqs. 5
and 6, the nonlinearity is enhanced with larger
wave numbers; this is the case with an undulator
that has a much shorter period length. (ii)Observed nonlinear effect is more or less thesame for all three lattice considered. (iii) There isno marked dependence on the number of IDs
included (see Fig. 5). (iv) With one wiggler in the
QBA lattice, the dynamic aperture decreases
monotonically with the momentum deviation (see241Fig. 6).
For all these findings, the reduction in the
dynamic aperture turned out to be not as large as
expected. This fortunate aspect should be
attributed primarily to the largeness of theradius of curvature in the 8 GeV machinecompared with those of the rings operated atlower energies. Note that the dynamic aperture
reduction mostly in the y direction is due to theassumed relation I}C 1 < 1 ky I. We also mention that the linear optics restoration describedabove does not help, in general, to improve thereduced dynamic aperture: Dynamic aperture
may turn out smaller with the restoration. We
wish to extend our analysis in future by working
with a more realistic field distribution, and in
addition, by taking various possible imperfections of the machine into account to examine thevalidity of our present conclusion.
References
1) L. Tosi and A. Wrulich: ST / M·88/ 12 (1988).
2) K. Halbach: Workshop on Magnetic Errors, Brookhaven, New York (1986).
3) L. Smith: ESG Technical Note-24 (1986).
4) R. Nagaoka, H. Tanaka, and M. Hara: RIKEN
Accel. Prog. Rep., 21, 228 (1987).
5) R. Nagaoka, H. Tanaka, K. Yoshida, K. Tsumaki,
and M. Hara: This Report, p. 227.

242
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-5.

Nonlinear Dynamics with Sextupoles

R. N agaoka, K. Yoshida, H. Tanaka, K. Tsumaki, and M. Hara

Large amplitude betatron motions of the electrons circulating in low-emittance storage rings
are greatly influenced by the nonlinear sextupole
fields needed for chromaticity correction. In
most cases the resulting dynamic aperture is notadequately large, for instance, to allow the offaxis beam injection. To improve the stability,
one needs to elucidate the dynamics of the
motion close to the dynamic aperture. An analysis is made taking a Triple Bend Achromat(TBA) lattice as an example (Fig. 1), in which
two families of chromaticity correcting sextupoles are located in the dispersive section. The
dynamic aperture obtained from tracking
calculationl) is shown in Fig. 2.
The Hamiltonian describing the motion is
given by
H = vx1x + vyly + (2Ix)3/2~jmAjmCosQjm- 3(2IJl/22Iy~ [2BlmcoSQlm + B+mcosQ+m

150
notation: [k,m],,------ ---,..--- ----- -,------------------

120
[3,4]

[3,4]
,
,
-------- - ,..----------,-,,, -------,
,
,
,

90

--- - -----

.

E

oS

>-

[3,3]

[1,0] .

60-._ ---- -,----- - ----

- - - - - - - - - ~ - --- --- - - -:- - - - - - - - - - - - - - - - --

30

·200

[1,0]
- - - - - - - - - ~ - - - - - - - - - -:- - - - - - - --

-150

·100

-50

o

50

100

X [mm]

Fig. 2. Prediction of the dynamic aperture in the
single resonance approximation for lowest·order(1st and 3rd) sextupolar resonances. Darl, squares
indicate the actual dynamic aperture o(the latticeobtained from the tracking calculation.

11/+ B_mcosQ- mJ

(1)

with
Qjm = j4>x- m8(j = 1, 3)(2)

Q±m = 4>x±24>y- m8

Action and angle variables are denoted by Iu and
4>u, respectively, and Vu is the betatron tune percell (u=x, y). Third and fourth terms on theright-hand side of Eq. 1 express the sextupole
2.0

50
nux/cell = 1.1597
40

I

nuy/cell = 0.6701

1.6

1.2

30

0

iii

a:;'"

co

Ic:
Qj

20

0.8

10

0.4

5

10

15

20
[m]

t{l] ~EJ~ tID
Fig. 1. Betatron and dispersion functions over the
Triple Bend Achromat (TBA) cell employed in thisstudy.

Q.
Ul

i5

potential expanded into harmonics ( - 00 <m < +00) .2) Time dependence of the system isindicated ty the variable B=27!s / C (s: longitudinal displacement, C: cell length). Coefficients
A jm , B lm , and B±m depend linearly on the strengthof sextupoles, and are also dependent on theposition of the sextupoles. From Eq. 2, one findsthat the resonances occur at vx=integer (lstorder), and 3vx =intger, vx ±2vy=integer (3rdorder).
In case we pick up particular harmonics in Eq.
1 and consider the effect of a single resonance,
we can transform the system to the rotating
frame to obtain the approximate static stability
boundaries. 3 ) In Refs. 2 and 4, m = 1 boundaries
are compared with the tracking results in the
Chasman-Green (CG) lattice and are found toagree remarkably well. This means that thestability in the CG lattice, without the harmoniccorrection, is strongly limited by the integer
resonance Vx =1. Generalization of the procedure
is done in Fig. 2, where stability boundaries are
depicted for a number of m's close to vx =1.1597.
Although boundaries shown tend to reproduce
more or less the actual dynamic aperture, one
cannot conclude from this that the dynamics is

243

R. N agaoka, et al.

determined by anyone of these resonances as in
the CG lattice. The figure implies the simultaneous contribution of several harmonics.
To look into more details, we observe, in Fig.
3, the phase space behavior at 1% coupling,which is obtained from the tracking calculation.
The outer curve and the islands appearing further out are close to the stability limit. The
number of islands and the shape of the innerclosed curve suggest the excitation of 7th-orderresonance. Furthermore, correspondent amplitude-dependent tune is found to be very close to1 + 1/7.
It first seemed to us rather unlikely to supposea resonance of such high order (7th) to be induced
by sextupoles. However, if we follow the perturbation theory, we find that, in principle, sextupoles can excite resonances of arbitraryorder. 5 ) In the following we shall confine ourselves to the one-dimensional case for simplicity
and also because we are mainly interested in thehorizontal dynamics.
The canonical perturbation theory developed
by Poincare and von Zeipel (PZ) defines a transformation of canonical variables from (</>x, Ix) to(1/I'x, Ix) with the generating function. 6 )S(</>x, Ix; e) =Ix· </>x+ ESl + E2S2 + E3S3 + ...

(3)
where E is a parameter representing the strengthof the perturbation (sextupole strength). The
idea is to define the function form of Sk ( k = 1, 2,, .. ) at each order of E so that the action Ix in the
new system becomes an invariant up to thatorder. When the theory is applied to our problem,
we find that following orders of resonance arepossible at each order of E:

Px [mrad]
1.5

c.::J

1 :"\

-30 '.J

Fig. 3. Phase space obtained from the tracking
calculation.

P [mrad] ....::.::.:~::.\x.' ., :~~'~;:~\c~'::K ) (,:15"0: '''; X [mm]:.

........:

Fig. 4. Phase space obtained analytically from theperturbation calculation of Poincare-von Zeipel(PZ).

El: 1,3
E2: 2, 4, 6
E3: 1, 3, 5, 7, 9
E4: 2, 4, 6, 8, 10, 12

To see if the observed features of the phase spaceclose to the stability limit can be explained interms of the 7th-order resonance, we performed a
perturbation calculation according to the PZ
theory up to O(E3). The new Hamiltonian isderived as
H (<Px, Ix; e) = vJx + C1 Jx 2

+ 3 /2lx 5/2 AM~ DAM·cos(A<px- Me),(4)

where Cl l is the coefficient describing thesecond-order tune shift with amplitude,4) A takes
the values 1, 3, 5, 7, and 9, and -co < M < +co,Fig. 5. Phase space obtained from the fictitious
tracking using the computer code HRMTRC.

244

R. N agaoka, et al.

Coefficient DAM is composed of triple summation
over coefficients A jm • Here we are interested in
the combination (A, M) = (7, 8). In the numericalcalculation, convergence for D78 was achieved at
I m I ~ 90. By performing the single resonanceapproximation in 0(£3) and by further transforming the system into the rotating frame, we
obtain the analytical phase space behavior,
which is shown in Fig. 4. The agreement with the
tracking result (Fig. 3) is quite impressive. We
found, in partic1ular, that harmonics with theindex [j, mJ = [1, oJ, [1, 1J, [3, 3J, and [3, 4J havethe major contribution to D78 . We notice an interesting relation that these harmonics indeed correspond to the boundaries of the single resonances surrounding the dynamic aperture in
Fig. 2.
Knowing that the dynamics is determined only
by few harmonics, we tentatively performed afictitious tracking with a computer code
HRMTRC7) in which the sextupole field is composed only of the selected harmonics. Figure 5
shows the resultant phase space including above
four components. The agreement with the "real"
tracking result is less impressive than that of theperturbative approach, but as expected, one canstill identify the occurrence of the 7th-order resonance. The discrepancy is due to the remaining
contribution of the background harmonics to theamplitude-dependent tune, which is missing in
Fig. 5. On the contrary, the remarkable agreement of the perturbative approach with the exact
tracking in phase space structure implies thatmost of the amplitude dependence of the tune
fortunately comes from the second-order effectwhich is rigoruosly incorporated in the perturbation calculation using the closed formula. Notealso the excitation of 8th-order resonance with alarger Ix in Fig. 5 which is absent in the real
tracking. We find this exitation to be reasonable,
however, considering how the four harmonics
enter the terms of O(c: 4 ) to induce 8th-orderresonance with M =9.
In the present study, we have shown, taking the
TBA lattice as an example, that in lowemittance rings, the dynamics of betatron motion
close to the dynamic aperture can be subject tohigher-order resonances of the sextupoles. Situation differs with the other lattice, of course,
depending on the details of their structure, but
we have encountered with many in which one canobserve the effect of higher-order resonances. 8 )When one attempts to enlarge the dynamic
aperture, following considerations might be ofsome help: ( i ) Proper choice of the tunes. One
should also have in mind the possibility ofhigher-order sextupolar resonances. (ii) Suppression of the harmonics that would otherwiseenhance the second-order tune shift with amplitude or limit the stability via first- and thirdorder resonances (see Fig. 2). (iii) Observationof the phase space and the amplitude dependenceof the tune to check the contribution of thehigher-order effect. If it is notable, one way is to
identify the harmonics that are responsible to it
and to try to perform the same steps as in (ii).
References
1) R. N agaoka, H. Tanaka, K. Yoshida, K. Tsumaki,

and M. Hara: This Report, p. 248.
2) E.A. Crosbie: ANL-HEP-CP-87-21 (1987).
3) E. Courant, R. Ruth, and W. Weng: SLAC PUB-3415(1984) .
4) R. Nagaoka, H. Tanaka, and M. Hara: RIKEN
Aeeel. Prog. Rep., 21, 228 (1987).
5) S. Ohnuma: Proc. US-Japan Semin. High Energy
Accelerator Science, p. 114 (1973).
6) A.J. Lichtenberg and M.A. Lieberman: Applied Mathematical Science, Vol. 38, Springer-Verlag, p. 71,(1983) .
7) R. N agaoka, K. Yoshida, H. Tanaka, K. Tsumaki,
and M. Hara: This Report, p. 245.
8) R. N agaoka, H. Tanaka, K. Yoshida, K. Tsumaki,
and M. Hara: This Report, p. 227.

245
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-6.

Pc;trticle Tracking in Harmonic Expanded Sextupole Fields

R. N agaoka, K. Yoshida, H. Tanaka, K. Tsumaki, and M. Hara

In designing a lattice for a low-emittance storage ring, optimization of intentionally included
sextupole fields is of great importance in achieving a large dynamic aperture of transverse
motions. I - 3 ) The procedutre usually taken is toexpand the sextupole fields into harmonics andby somehow identifying the particular harmonics
that limit the stability, try to suppress themeither by introducing additional sextupoles in thelattice, or by modifying the optics of the lattice.
Apart from the problem of whether or not one
can successfully eliminate them, the first task istherefore to find out the harmonics that are most
responsible to the dynamic aperture. In certain
optics, one simply finds that the second-orderamplitude-dependent tune shift is dominated byjust one harmonic and that this harmonic also
determines the dynamics of large amplitude
motions. It is possible, in such a case, to step
forward to make a theoretical analysis of thesystem using the single resonance approximation
to predict the phase space structure and thestability limit. I •2 )Generally, however, it is not the case. There
are several harmonics that sin1ultaneously influence the dynamics and they are not necessarily
identified from the second-order tune shifts. For
this reason, we have developed a computer code
"HRMTRC," for an attempt to extract the net
effect on beam dynamics brought about by thecertain selected harmonics, by performing thefollowing "fictitious" particle tracking. Namely,a tracking in which the field is composed only of
specified harmonics. Below is shown the brief
scheme as well as some results of the application
using HRMTRC.
We initiate from the Hamiltonian expressed interms of action and angle variables, with the
sextupole potential expanded into harmonics.
(See Eq. 1 and below of Ref. 4 for the explicit
form as well as for the meaning of the notations.)
Using the relationsz = /2Iz • cosrPz,(z =x, y)pz= -/2Iz·sinrPz,(1)

we then rewrite the Hamiltonian in terms of x,
Px, y, and py:

2
H=PL
2 + V(x, Px, y, py; 8)x +a2f.J.x 2f.J.y

(2)

where

v (x, Px, y, py; fJ)x'\J2= - + 2 - + a (8)x 3+ b(8)xy2
2f.J.x 2f.J.y2+ c(8)x 2px+ d(8)y2px+ e(8)xypy+ f(8)xPx 2+ g(fJ)xP/+ h(fJ)ypxPy+ i(8)Px 3+j(fJ)PxPy 2(3)
and f.J.z = liz - 1 (z = x, y). Ten coefficients a(8) j(8) are given by the infinite sum of products of
the harmonics A j m, B lm , and B±m,2) and thesinusoidal functions. The first three coefficients
read, for example,a( fJ) = + ~(A3m+ Alm)cos mfJmb(8) = -3~(2Blm+
B+m+ B-m)cosm8mc(8)= -3~(A3m+
A lm / 3)sinmfJm(4)

Remaining coefficients have similar expressions.
Out of the infinite sum over m, our aim is to keep
only of those selected ones. This requires us tocarry out a numerical integration at every pointin the ring since the effects of harmonics are, bythemselves, ditributed everywhere. On the other
hand, it is well known that non-symplectic
numerical integration of the canonical equations
may lead one to spurious damping or excitationof the system. With our present Hamiltonian,
however, the potential is fully nonlinear in
momenta, and in addition, the problem is twodimensional (see Eq. 3). Canonical integration
therefore becomes non-trivial in this case and weshall content ourselves with a method which isaccurate only to the lowest order in the integration step:
For a system with the Hamiltonian
H=p 2/ (2f.J.)+ V(x, p; t)(5)this approach defines a mapping to the newcoordinate system (x b PI) with the generating
function(6)

Suppose X=%o, and P=Po at time t = to. With h,

246

R. Nagaoka, et al.

the integration step, one chooses G(XI , p, t) at t =to + h to be
G(xl , p, t) = - [p2/ (2,u) + V(xl , p, to)]· h(7)The resultant canonical relations arex= Xl + p l ,u • h + Vp(XI' p, to)h,

(8)

PI

=p + VXI(XI , p, fo)h,(9)

HI = V XI (Xl, p, fo)[P l ,u + Vp(XI' p, to)+ Vt(xl , p, to)] h,(10)where the subscripts denote partial derivatives.
It should be stressed that, with the above transformation, the new Hamiltonian HI has becomeof O(hl). Since XI = ~ and PI = Po at t = to as seenfrom Eqs. 8 and 9, it follows that

+ O(h 2 )PI (t) = Po+ O(h2)XI (t) = ~(ll)equations for the momenta, we thought it better
to use the lowest-order formulas and take h to be
sufficiently small.
Input data for HRMTRC are the same as forthe program DYNAM:3) Strength, location, andbetatron phase of the sextupoles. Prior to tracking, ten coefficients a ((J) - j (8) are prepared atevery integration point in the ring, taking
account only of the specified harmonics. Divisionof 8, namely, the integration step size h is determined from the convergence of the integration as
well as from the degree of agreement with theresult of DYNAM when all the harmonics areadded up. It turned out that with the latticeconsidered so far, an accuracy of ""'-'1 % is
obtained when the longitudinal increment istaken to be as small as 1.5 mm. This amounts tothe division of the ring into ""'-' 20,000 pieces incase of single cell tracking which is permissible(12)

One therefore obtains x(t) and p(t) from Eqs. 8
and 9 within the accuracy of O(h l ) by replacing
XI and PI by ~ and Po, respectively. Note howeverthat when the potential is momentum dependent,
Eq. 9 generally cannot be solved analytically forp. Indeed, in our problem coupled equations forPx and py must be solved numerically using, forexample, Newton's method. A trial has been
made, in analogy with the techniques found in
Ref. 5, to develop an integration scheme which isaccurate to higher orders in h, but since it inevitably involves several steps solving the coupled

Px [mrad]
5.0

(a)
2.5'"

\

\

\

\

_12f-O-lt---+---t---I-0- -t---+!6f0--t---l
120 X [m m]" -25)

Lo

[k,m]

[1,0]

(a)

120

P x [mrad]
5.0

90

E
oS
>-

60

I

X [mm]

120
OLL~~~~~-L~_ _L-~~_ _~~~

-200

-150

-100

-50

0

50

100

X [mm]

Fig. 1. Comparison of the dynamic apertures
between the HRMTRC results (dark squares anddark triangles) and the theoretical predictions inthe single resonance approximation (solid lines).
Dark squares: Single effect of the harmonics [ k,mJ= [1, oJ (lst-order resonance). Dark triangles:
Single effect of the harmonics [k, mJ = [3, 2J (3rdorder resonance).

[k,m]

[3,2]

-5.0

(b)

Fig. 2. Phase space obtained from the tracking
calculation with HRMTRC. Horizontal-vertical
coupling is taken to be 1% . (a) Effect of harmonic[k, mJ = [1, oJ (lst·order resonance). (b) Effect of
harmonic [k, mJ = [3, 2J (3rd-order resonance).

R. N agaoka, et al.

(a )Px [mrad].,1.5

r..::;,::............ . ~ \ ... ....

_-,
I

(b)

Fig. 3. Phase space with a combined effect of several different harmonics. (a) "Fictitious" tracking
result with HRMTRC. Four components [k, mJ =[1, oJ , [1, I J, [3, 3J, and [3, 4J are included. (b)"Real" tracking result with DYNAMY Horizontal-vertical coupling is 1% in both cases. Calculations are done with the Triple Bend Achromat(TBA) lattice. 4 )247

for an ideal lattice. The cpu time measured isroughly 60 s for 250 turn tracking using thecomputer machine F ACOM M780.
In Fig. 1 we show the dynamic apertures calculated by HRMTRC, which demonstrate the effectof single harmonics for two cases. A ChasmanGreen lattice in its "high beta" mode is used as
an example. 1 ) Corresponding phase space structures are observed in Fig. 2. Characteristics ofthe first-order (a), and the third-order (b) resonances can be seen. Compared in Fig. 1 by thesolid lines are the theoretical predictions in the
single resonance approximation. The very good
agreement with the results of HRMTRC ensuresthe validity of both approaches.
The phase space in Fig. 3 provides an example
in which several harmonics altogether determine
the behavior of a large amplitude motion. In thisparticular case, effects of harmonics are combined to induce higher-order resonances (7th and8th); this is also confirmed by DYNAM.4} Here
we find the significance of HRMTRC: The
analysis of higher-order resonances is usuallyquite tedious in the perturbation theory. Finally,
we also refer to the apparent limitation of
HRMTRC. It can be an especially helpful tool
when the influence of the harmonics are not widely spread. The analysis might be difficult, forinstance, in case the dynamics involves tune
shifts with amplitude caused by a large numberof harmonics, even though the stability limit isdetermined by only few of them.
References
1) R. Nagaoka, H. Tanaka, and M. Hara: RIKEN
A eeel. Prog. Rep., 21, 228 (1987).
2) E. A. Crosbie: ANL-HEP-CP-87-21 (1987).
3) R. Nagaoka, H. Tanaka, K. Yoshida, K. Tsumaki,
and M. Hara: This Report, p. 248.
4) R. Nagaoka, K. Yoshida, H. Tanaka, K. Tsumaki,
and M. Hara: This Report, p. 242.
5) R.D. Ruth: IEEE Trans. Nucl. Sci., NS-30, 2669
(1983) .

248
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-7.

Computer Code CATS: A Code for Sextupole Optimization
R. N agaoka, H. Tanaka, K. Yoshida, K. Tsumaki, and M. Hara

The goal of the lattice design in storage rings
is to attain a magnet arrangement which, withfulfillment of the required performance of themachine, is capable of a long term beam accumulation. The design procedure is roughly divided .
into two parts: (1) Construction of linear optics;(2) Verification of dynamical properties by tracking a particle in computer simulation. Steps 1
and 2 continue repeatedly until a satisfactory
solution is found. There are many computercodes with which to do these jobs. Codes such as
Synch and Magic are for optics designing,l) and
Racetrack,2) Patricia, and Teapot 3 ) are for particle tracking.
One big reason for the need of step 2 is thestrong nonlinearity of the machine due to sextupole magnets: Sextupoles are introduced instep 1 for chromaticity correction, but since they
inevitably limit the transversal stability, thedynamic aperture is measured in step 2. In lowemittance machines where the strength of sextupoles tends to be large, the reduction of the
dynamic aperture becomes above all serious.
What one does for the cure is to include additional sextupoles, i. e. the "harmonic" sextupoles,in the lattice to cancel the origin of instability.4.5)
This is not trivial in general, since with sextupoles, the problem is by nature nonlinear.
Optimization of the sextupoles is therefore not
only important but also accounts for a large
portion of the work in the lattice design.
Being prompted by the necessity, we havedeveloped a computer code that would mediate
between the two groups of codes mentioned
above: A code that optimizes the strength ofharmonic sextupoles to enlarge the dynamic
aperture .. "CATS" is what we named for thecode, since "Correction of Amplitude-dependent
Tune Shifts" was initially the main purpose of it.
As seen in Fig. 1, the stream of the procedureusing CATS is composed of two parts: the sextupole optimization and the tracking. This isbecause, as already stated, the sextupole optimization being a complicated nonlinear problem, itt All the graphic figures take the 8 Ge V Chasman-Greenlattice in its hybrid mode7} as an example.

has no definite recipe; it must be done more orless by trial and error. There are also several
graphic routines at each step. Below we explain
main features of the code as well as the functionsof supplementary graphic routines. t( I ) CATS and related graphic routines
CA TS is composed of more than 20 small
subroutines. Some of them are used to calculate
the quantities needed for the optimization: The
linear optics, linear chromaticity and its correction, harmonics of the sextupole potential, distortion functions, second-order amplitude-dependent tune shifts, and so on. Basically, calculationin CATS is done for a unit superperiodic cell of
the ring. In the input file must be included theinformation on the magnet arrangement as wellas the specification of the sextupoles to be optimized.
The optimization is performed by n1aking aleast-square fit of a certain function defined in
the routine "MODLFN" which is to be linked
with CATS. MODLFN is provided with common
blocks of harmonics of the sextupole potential
and coefficients for the second order tune shifts

CATSOPT
envelop
Linear Optics
Calculation,
Optimization of
Sextupolesfunctions

CATSPLT
harmonic expansion of
2nd order tuneshifts

CATSPOSposition dependenceof harmonics

CATSRAP
dynamic aperture
prediction in the single
resonance approximation

CATSDAP
Particle Tracking
In the Ideal Lattice
In the Presenceof Sextupoles

figure ofdynamic aperture,} - - - ! - -CATSSPC
betatron tune spectra

CATSPHSphase space map

Fig. 1. Stream of optimization procedure
with CATS.

R. Nagaoka, et at.

tHHJ.

CA TS 0 PTtHt t1249

0ptlCS n~me .. hb86<:1b.tws

40

2-FEB-SQ 13:55:11

1.6

:§
C

0
....
0

E 30

1.2

~

cO

+->

c...
<l>
a.
0

(l)

0

m

O.S

20

0.4

Fig. 2.
t1t:tt:t

CATSP L T

Cell Lenqth:
61.60 {m]Nux/Cell:
2.1562
Nuy/Cell:
0.9259GZIX/CeU:-5.2534
GZly/CeU:-1.7524Betllxmllxl
33.7714Im](e 07 )
Betllymox:
26.9072 {m])(~ 04
8etllxmlOl
1.12Q7Im)(e LO )
eto· 0.000 [m)betllY· 4.028" [m)8etllymln:
4.02B4Im)(e LO )
Etomox:0.3800Im))(I) 05

Linear optics function over a superperiodic cell.
t1t:tt1

2·FEB-sg 14:17:10

hb86o b.h rm

A3m-A3m

Alm ' Almmm

81m'A1 m

81m ' 81m

m

m

8 - m'8-m

8 -m-8' mmm

Fig. 3.

Harmonic expansion of the second order tune shifts with amplitude.

with amplitudes. Depending on the situation, onethen defines, in terms of these quantities, a "best"form of the model function to be least-square
fitted. By this way, one can make an attempt
either to minimize tune shifts with amplitudes orto eliminate the selected harmonics or any combination of these two.
In addition to the fitting result, CATS provides
output files with which one can execute following graphic routines: ( i ) CATSOPT: Draws afigure of the envelope functions over a superperi-

odic cell (Fig. 2). Some of the useful information
as regards the optics are also listed aside. (ii)
CA TSPL T: Draws a figure that demonstrates
how each of the harmonics contributes to thecoefficients describing the second-order amplitude-dependent tune shifts (Fig. 3).4) This helps
identifying the individual harmonics responsible
to the tune shifts. (iii) CATSPOS: For a given
integer specifying the harmonics, draws a figure
over a superperiodic cell that displays the position dependence of the harmonics (Fig. 4). This is

250

R. N agaoka, et al.

CATSP0S f:J.f:J.f:J.

f:J.f:J.f:J.

0ptlcs nome -hb86ob.tws

2'FEB'BIl 115:03:48

m -PosItIon Dependence of the Se xtupolor HormonlCs

Cell LenQth:
61.60 Iml
Nux/Coli:
2.1562
Nuy/C.lli
0.e258
Gu./Celh-5.2534
Guy/Colli-1.7524

'160
-120

(\J

-.....

• 80

(")

.§

- 40

((.)

0

2
0

E

<to
:r::

0
-~o

-80
·120
-150

'2000

5

10

15

20

25

30

P~th

35

40

45

50

55

60

Length [mJ

Fig. 4. Position dependence of the harmonics for a given m. The figure takes
m=l.
t1tHt

CA TSRAP

t:Sttt:S

Fllenome -hb86ob.hrn

Dynomlc ,",pertvre predlcted by Resononce ,",pproxlmotlon

notl:ltlOn: [k,ml•i {1,6]

tvrn" - 500
eml1:tDnCe - 0.4QO-OB Iml
uqmDx •
0.338 Imml
$lqmoy 0.103 Imml
(f'vll c:ouphnql(Nxlmox. ·01.0. 70.0
(Nylmox· 14B.3--_._. ---,---._----

120: hbB6obh.dop\lITH HARM.SEXTS.(OYNAMI

[3,6]

>60
[3,6J

30

x

100

Fig. 5. Comparison of the dynamic aperture between the theory and the tracking.
Theoretical predictions rely on the single resonance approximation (solid lines).
Dark squares are the tracking results calculated by DYNAM.

useful in determining the optimal location of the
sextupoles in case one wishes to eliminate theeffect of a certain harmonic. (iv) CA TSRAP:
Calculates stability limits brought about by eachof the harmonics using the single resonanceapproximation,6) and draws them in the x-y planein comparison with the actual dynamic aperture(Fig. 5), Although the calculation includes only
the contribution of the lowest-order resonances(lst and 3rd), this provides another view of theeffect of harmonics on the dynamics which may
not be clear from the tune shift analysis using
CATSPLT.

(II) DYNAM and related graphic routines
Owing to the trial and error nature of the
optimization procedure, the effectiveness of
optimization must be checked at once in terms ofthe dynamic aperture. This is readily done by
DYNAM which reads the output file of CATS
containing necessary information for particle
tracking: Strength and location (betatron phaseadvance) of the sextupoles, DYNAM is a tracking code, but it is merely organized to calculate
the dynamic aperture of an ideal lattice in thepresence of sextupoles. More realistic tracking
with Closed-Orbit Distortions (COD), or correc-

R. Nagaoka, et at.

CA TSOAP tItItI

tlfUJ

251

DynomlC Apertureof the Ideol Lottlce

2·FE8·8Q 18:IQ:04

40'---~--"---r--~----.---'----'--~----~~: hb86obh.dop•'With hcrmonlC s:exts.
turn~ • 500
eml ttonC8· 0.420-08 (mlslqmox •0.311
Imml
S1qmo~ •0.150 Imml
(full couphnQ)(Nx)mox· -98.9.
86.8(Nylmox. 161.0--~- -----------i------------~ ------------~ -----------

30

-. -

:

:

1

1

:

:

i

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

: hb86obc.dop
no hCl"mOnlC SQxts.

10

:

i

:

I

l
:

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

:

A;

l

--~----------I

! :-!

-40

-20

0

Figure of the dynamic aperture calculated by DYNAM.

CA TSPHS

fH11'I4020

X [mm)

Fig. 6.

turM· 50
emlttonce· 0.420-08 Iml$lqmox •0.311
Imml$lqmoy •0.150
Imml(full couphnq)(Nx)mox· -27.3.
35.7(N~)mox.
106.5

F' IJeno me • hb86ob.phs

tHlti

2·FEB·eg 17,1hse

Phose Space I2Ibtolned Prom Trocklnq

Px

L. _ -.~ !
./

\.

/

x

Y

-...J
turnll-500

coupllnq aseal e:Fig. 7.

Xmax g 40.0mm
Px maxg 2.0mrad

n

0.0

~
0.0

6.0mm
0.6mrod

YmCiX -

Pymox-

Phase space map obtained from the tracking result of DYNAM.

CA TSSPC tltIti

tltIti1%0ptlCS nome·

hb86<:lb.phs

2'FEB-BQ 17.20:25

~

n

0.1

0.2

NUX

0.3

0.4

0.5

0.1

0.2

NUY

0.3

0.4

0.5

turnlt-500( 1. 0)( 2. 0)( 3. m( O. 1)
O. 2)
O. 3)

0.16200
0.32400
0.48600
0.165990.33197
0.497960.32799
0.00399
0.493970.16997
0.48999
0.15802

1. 1)
1.-1)
1. 2)
1,'2)
2. 1)
2.-1)

n

Fig. 8. Betatron tune spectra. Fourier analysis is made on the turn by turn phasespace data calculated by DYNAM.

252

R. Nagaoka, et at.

tion of COD, etc. must be done with codes such as
RACETRACK in step 2.
Like other kick codes, DYNAM treats sextupoles as thin elements. Courant-Snyder coordinates are employed in two dimesions and theintegration scheme is quite simple: Multiplication of a sinusoidal matrix between the sextupoles, and addition of amplitude-dependent
kicks on the gradients at the sextupoles. Following RECETRACK,2) the dynamic aperture ispursued via iteration using the bisection method.
Tracking calculation is preceded by preparing
an input file controling the conditions of thecomputation. Dynamic apertures can also be
calculated for a number of couplings in a single
run. The cpu time needed to obtain the outercurve of the dynamic aperture shown in Fig. 6(Condition: 500 revolutions and 10 iterations eachfor 12 couplings) is, for example, 37 s with
MICROV AX 3600.
There are three graphic routines that can be
executed with the output files of DYNAM: ( i )CA TSDAP: Draws a figure of dynamic aperturesin the x-y plane (Fig. 6). (ii) CATSPHS: Reads
the turn by turn data on (x, x', y, y') and draws afigure of the phase space mapping (Fig. 7). (iii)
CATSSPC: This also reads the phase space dataand performs Fourier analysis of the betatrontunes to provide the plot shown in Fig. 8. CATSPHS and CATSSPC are particularly useful inanalyzing the dynamics of large amplitude
motions.
We have shown the structure and the capability of the computer code CATS developed for the
sextupole optimization. The main feature of thecode is that procedure for the optimization is
supported by several supplemetary routines, including the particle tracking, which help to findthe right direction in the trial and error work.
The code has been quite useful in our latticedesign,1) and we still hope to extend its capability
in future.
References
1) A.A. Garren, A.S. Kenney, E.D. Courant, and M.lSyphers: FN -420, 0170.000 (1985); A.S. King, M.l Lee,and W.W. Lee: SLAC Report No. 183 (1975).
2) A. Wrulich: DESY Repo'rt·84-026 (1984).
3) H. Wiedemann: PEP-220 (1976); L. Schachinger and
R. Talman: SSC-52 (1985).
4) R. Nagaoka, H. Tanaka, and M. Hara: RIKEN
Aeee!. Prog. Rep., 21, 228 (1987).
5) E.A. Crosbie: ANL-HEP-CP-87-21 (1987).
6) E. Courant, R. Ruth, and W. Weng: SLAC PUB-3415(1984).
7) R. Nagaoka, H. Tanaka, K. Yoshida, K. Tsumaki,
and M. Hara: This Report, p. 227.

253

RIKEN Accel. Prog. Rep. 22 (1988)

V-2-S.

Study of the Beam Injection to a 6 GeV Storage Ring

H. Tanaka, R. N agaoka, K. Yoshida, K. Tsumaki, and M. Hara

The beam injection to a 6 Ge V storage ring
was studied and the main parameters of thebeam injection were determined.
It is planned that electrons and positrons arerepeatedly injected into a 6 Ge V storage ringfrom an injector synchrotron to storage high(about 100 mA) currents. To perform multiinjection efficiently, we adopt an off-axis injection method. This method requires strong (a few
kGauss) bump magnets that are capable of onand-off within a few j.lS and have a more than 1
j.lS flat top (the circulating period of this ring isabout 4 J1.s). In case when we find these requirements are too severe to design bump magnets, wewill introduce following two concepts to overcome difficulty of the magnet design. One is a"fractional betatron tune," which allows thechange of the on-and-off period to be easy, about
10-15 J1.S corresponding to the period that an
injected beam returns to a septum magnet. The
other is the use of "many bump magnets," which
reduces the strength of a bump magnet.
As an injection point, a dispersion-free longstraight section of 7 m was selected because noother long section with high f3x was found. The
basic design of the beam injection and a lattice 1)
configuration of one cell are shown in Table 1
and Fig. 1.
Assuming that a beam has a Gaussian distribution, we calculated the relative beam positions
around a thin septum and the amplitude of abump orbit from the standpoint that a beam loss
at the septum is only due to the static beam
distribution. The beam loss consists of threeparts. First, loss occurs when an injected beam
passes through the outside of the septum only atonce (beam loss 1). Second, loss occurs when an
Table 1.

Basic conditions of the injection system.

Injection method
Bump orbit recovery period···Option "fractional betatrontune"
Beam injection point

off-axisis
1 turn (about 4 j..ls)
3- 4 turn (10- 15 j..ls)

Dispersion free longstraight section (7 m)
4 (2 x 2)
N umber of bump magnets
6(3X3) or 8 (4 X 4).. ·Option "many bump magnets"

injected beam passes through the inside of the
septum repeatedly, damping its transient large
emittance to equilibrium one (beam loss 2).
Third, loss occurs when the beam storaged anddamped passes through the inside of the septum
repeatedly (beam loss 3). The beam loss 2 and 3
are estimated under the condition that a beamdiffusion rate is sufficiently fast to recover abeam constant distribution during the beam circulating period. The results estimated for four
5 0 , - - - - - - , - - - , - - - - . - - - - - - - - - r - - - , - - - - - - . 2 .0

40

_

1.6

:§

30

..§

.r---..

1.2

c

3

VI

B

<...
Q)

(l)

0.8 ~

OJ 20

o

Fig. 1. Lattice configuration of one cell.

different beam losses are shown in Fig. 2.
Though a large amplitude of the bump orbit
insures a small static beam loss, we need a large
dynamic aperture. A large amplitude, on theother hand, reduces a dynamic aperture significantly and increases dynamic beam loss. That is,a realistic injection efficiency depends on thebalance of a static beam loss and a dynamic
beam loss. The relative beam positions and theamplitude of the bump orbit should therefore be
decided considering the reduction in the dynamic
aperture, as described later.
The bump magnet arrangement was determined in consideration of the strength of a bumpmagnet and easiness of the installation of equipment. For the current lattice structure and tominimize the number of magnets, we examined
the three cases in which with two pairs of thebump magnets are used as shown in Fig. 3. The
strength of the bump magnet was calculated byan original computer code "INJECT," which wasH. Tanaka, et at.

254

Center of bump orbit

Center of injetion orbit

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

Septum magnet\

IiI ~;-~-~ -:- - -­tI

CASE.1..

CASE·2..

CASE·3___ --------1A

B

I

:

C

:c

14-----014-------.1

o

~~

1 mm

1 mm

o

o : Amplitude of bump orbit

2

3

4

Bump magnet kick angle (mrad)

Case Total static A (mm) B (mm) C (mm) D (mm)loss (%)[ O"oJ[O"IJ[0"1 J

E

0.3

Qi

tI

c:

a

0.03

b

1.5

c

3.0

d

9.0

2.06
[ 4.8J
1.68
[3.9J
1.59
[3.7J
1.51
[3.5J

6.56
[ 4.0J
4.26
[2.6J
3.72
[2.3J
3.12
[1.9J

8.53
[5.2J
7.22
[4.4J
6.89
[ 4.2J
6.56[ 4.0J

18.59
14.98
14.11
13.18

0"1: O"(Injected beam) = 1.64 mm, 0"0: O"(stored beam) = 0.43 mm.
Thickness of septummagnet = 1.5 mm.
1 mm allowance is taken at both sides of septum
magnets.
D is defined as the distance between center of reference
orbit and center of bump orbit.

Fig. 2. Results of calculated beam losses due to static
beam distribution.

1.40 m1.29 m~0 . 22 m, Iort',.:- _~-------- ---

Dispersion
free straight- --- section

Case-1A

B-A_A-[)B- B-EJ--

Case·2AB

8-.-----80 -08-8----_-8-80 -e-EJ-A
Case-3A~: Bending magnet

0: Sextupole magnet

I

OF magnet

B~~

OD magnet
Bump magnet

Fig. 3. Three kinds of bump magnets arrangements.

confirmed to work correctly with the result of"RACETRACK."2) The calculations are shown in
Fig. 4, from which the strength of a magnet isfound the best in case-1 (a pair of bump magnets
is located with a bending magnet between). The

III

E
c..
E
::J
.a
'0

L= 0.2

0.3•.. L=
L = 0.4

CI

0.2

0.1

.c:

ac:
~

u;

0.0
0

2

3

4

Bump magnet kick angle (mrad)Fig. 4. Correlations between bump magnet kick angles
and bump orbit amplitudes (upper diagram) andbetween bump magnet kick angles and strenght ofbump magnets (lower diagram).

difference between case-l and case-2 (one bumpmagnet is located in the long drift space next tothe bending magnet and the other in the longstraight section) is not substantial. From easinessof installation of equipment, case-2 is the best
because a crotch absorber of about 1 m should beinstalled besides the bending magnet. It is quite
tight to locate both crotch and bump magnet in ashort drift space besides a bending magnet of
1.29 m (see Fig. 2; two drift space bedides thebending magnet have different lengths, 1.40 and
1.29 m). After all, we selected case-2 especially to
avoid difficulty in installation.
We suspected that generating a bump orbit
would influence beam dynamics, because a few
sextupole magnets exist on the orbit. The sextupoles induce a linear tune shift in accordancewith the amplitude of the bump orbit at theirpositions to shift a workpoint. A simulation
subroutine of off-axis injection was added to"RACETRACK" to study the effect of the bumporbit on beam dynamics. Figure 5 shows therelation between the dynamic aperture and thebump orbit existing time in the turn number.
Although the dynamic aperture is much reduced
at the constant bump orbit, the reduction of the
dynamic aperture is a little under the condition
that the bump orbit only remains at a few turns
from injection. Since the fractional tune of hori-

255

H. Tanaka, et al.

60

R

CII

]

50

\

G;
0.
IV

40

U

turn nO.=500
at Injection point
phase=O.Odeg.

~

'E

V

IV

c

>-

0

30

20

o

10

20

dynam ic apertureat stational bump orbit(29.834mm)

30

Bump orbit generating period in turn no.

Fig. 5. Dependence of the dynamic aperture on thebump orbit existing time in a turn number. X-Y coupling is 0.01 and the tracking turn number is 500. The
calculating point is at the center of the straight section. The amplitude of the bump orbit is 20.6 mm.

[J

60

;;; E

40

~~

20

E

A
-.::r

o

~

•
...
•

:::J

~C!
0.
'"

0
II

·20

.~ ~

·40

C

·60

E::
",0.
:::J

>-0
C CJ

./

..,/'"-

X+Btdplp=-O.5%
X+Btdplp=O.O%
X+atdplp=+O.5%
X-atdplp=-O.5%
X·atdplp=O.O%
X·atdplp=+O.5%
X+(-) : Initial phaseof tracking=O.O(180)deg.

·80

Bump

·100

Is generated

o

20

10

orbit

at Initial 5 turnAmplitude of bump orbit (mm)aperture with momentum errors was investigated under the bump orbit condition mentioned
above. The dependence of the dynamic apertureon the amplitude of the bump orbit for threekinds of momenta is shown in Fig. 6, from which
the dynamic aperture is found to be kept 40 mm
in the injection side even at the largest bump
amplitude (about 20 mm). Although only theeffect of the bump orbit on an ideal ring wasstudied here, it was found, from other error
analysis, 3) that practical gradient errors did not
greatly reduce the dynamic aperture. This meansthat the 6 GeV high f3 solution is not sensitive tothe relation of a betatron phase advance among
the sextupoles and that a high recovery ratio will .
be achieved by sufficient correction of closed
orbit distortion (COD). Thus we adopted thebump orbit with an amplitude of 18.59 mm. In
Fig. 7, an aspect of the phase space around 40
mm amplitude is shown. Although emittance
growth due to bump orbit off is found, the phasespace is clean and no micro-structure is found as
expected .
In addition, we investigated whether theenergy aperture was enough for an injected beamfrom the synchrotron. It is expected that thelongitudinal condition of the injected beam isdP / Po = 0.001, ($z = 2.0 cm. The energy aperture

Fig. 6. Dependence of the dynamic aperture on theamplitude of the bump orbit. X-Y coupling is 0.01 andthe tracking turn number is 500. The calculating point
is at the center of the straight section. Existing time of
the bump orbit in a turn number is 5.

O(P/P O)

(%)

5.0
2.5

P x (mrad)

Py (mrad)1.5

2.5{l't (nsec)\

1 turn·60

Injection
point (.40.0)

2 1urn \

·30

30

i

X
60

(mm) .10

. 0

Y
10

(mm)

I

4 turn3 1urn·2.5

I/

Tu rn no.=500
81 Injection polnl
coupllng=O.Ol

.:

-1.0

-0.5

1.0

Injected beamo(P/PO)=0.1%°t=0.033nsec

-2.5

-5.0
'1.5

Fig. 8. Energy aperture with the injected beam.
Fig. 7. Phase space of a particle injected at 40 mm
amplitude from the inside of the ring. The amplitude of
the bump orbit is 18.59 mm and existing time in a turnnumber is 5. This phase space represents coherent
betatron oscillation. Amplitudes of oscillation are calculated under the condition that the bump orbit is a
center of osciallation while the bump orbit is on andunder the condition that the reference orbit is a centerof oscillation while the bump orbit is off.

zontal betatron oscillation is about 0.20, themaximum turn number under existence of thebump orbit is 5 turns even if a "fractional
betatron tune" concept is taken. The dynamic

Table 2. List of the final parameters for beam injection.
Amplitude of the bump orbit:
Distance between the bump orbit
and the inside of septum:
Distance between the injection orbit
and the outside of septum:
Distance between the injection orbit
and the inside of septum:
Arrangement of bump magnets:
Strength of bump magnets
magnet-A
magnet-B

18.59 mm
3.06 mm
7.56 mm

9.53 mm
Case-2
3.046 mrad
0.573 mrad

256

H. Tanaka, et at.

calculated at 10 Me V 4 ) RF maximum voltage ofthe storage ring is shown with the injected beamin Fig. 8, indicating sufficiently large for the
injected beam.
The parameters decided for the injection system are listed in Table 2.
The injection effeiciency has not been calculated yet, but an injection efficiency calculation
subroutine is being added to "RACETRACK"
and it will be estimated soon. Moreover, we hope
to investigate the effect of the bump orbit on thepractical ring with errors under the condition

that the COD is corrected in the ring by theextension of the injection simulation subroutine.
References
1) H. Tanaka, R. Nagaoka, and M. Hara: RIKEN

Aeee!. Prog. Rep. , 21, 225 (1987).
2) A. Wrulich: DESY Report, 84- 026 (1984).
3) RIKEN Accel. Group Synchrotron Radiation Facility
Planning Section: CDR of STA 6Ge V SR Project, 2- 1
(1988).
4) T. Yoshiyuki, T. Kusaka, and M. Hara: RIKEN
Aeee!. Prog. Rep. , 21, 235 (1987).

257
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-9.

Beam Lifetime of the 6 GeV Electron Storage Ring
K. Tsumaki

In an electron storage ring for a synchrotron
radiation source, the beam lifetime of several
tens of hours is required. The beam lifetime in anelectron storage ring depends on the gas pressure
in a vacuum chamber, a vacuum chamber aperture, and a beam density. We then need to know
the relation between the beam lifetime and thesequantities. Thus, the beam lifetime has beenstudied by using a computer code ZAP. 1)
Physical processes which determine the beam
lifetime are gas scattering, single Coulomb scattering within a bunch (Touschek scattering), anda quantum effect. Since the quantum lifetime canbe easily controlled by RF cavity voltage and the
RF voltage can be determined to have an enoughlifetime, calculation of the quantum lifetime is
excluded. In this paper, we report the calculation
results of the gas scattering lifetime and theTouschek lifetime.
(1) Gas scattering lifetime
When an electron beam circulates in a vacuum
chamber, it collides with residual gas and someof electrons are lost. There are two processes ofscattering. One is the elastic scattering by nuclei
and the other is the Bremsstrahlung by nuclei.
An electron scattered by nuclei changes its direction of movement and a large change in the
movement direction leads to a collision with avacuum chamber. On the other hand, electrons
which lose more energy than some limitingenergy by Bremsstrahlung leave the energy aperture and get lost.
The beam lifetime affected by elastic scattering is determined by the smallest size of anaperture which is the aperture where an undulator is installed. The lifetimes determined byelastic scattering and Bremsstrahlung are calculated as a function of a chamber aperture under
the conditions listed in Table 1. Residual gases
Table 1. Conditions for calculation of the gas scattering
lifetime.
Momentum half-aperture .:1 E / E
Averaged beta value f3y
Beta value at undulator section f3y
Gas species
H2

CO
Pressure

2.2%
18.39 m9.82 m75%
25%

10- 9 Torr

10000~-----------------,

100 +-.......--,--......-~..---r-r---,r--"".--;

o

10

20

30

40

50

Chamber Aperture (em)Fig. 1. Gas scattering lifetime as a function of a chamber
aperture. 'Te , the lifetime determined by elastic scattering; 'Z'h, the lifetime by Bremsstrahlung; 'T, the total
lifetime by gas scattering.
100000
10000

l!!
:::I
0

1000

~

100

:S

i::::;

10

10 10

10"9

10"8

10"7

Pressure (Torr)

Fig. 2. Gas scattering lifetime as a function of gas
pressure.

are assumed to be H2 and CO. In both elastic andinelastic scatterings, the scattering cross sectionis almost proportinal to the square of the atomic
number Z, and thus the lifetimes are almost
governed by CO gas.
Calculated results are shown in Fig. 1. The
lifetime determined by elastic scattering isalmost the same as the lifetime of inelastic scattering for an 8 mm chamber aperture. For alarger chamber aperture, the lifetime is almost
governed by inelastic scattering; however, very
long lifetimes are realized for chamber apertureslarger than 8 mm. Figure 2 shows the lifetimes
for an 8 mm and a 40 mm chamber aperture as afunction of residual-gas pressure. Chamber apertures of 8 mm and 40 mm correspond to the258

K. Tsumaki

narrowest undulator section and the normal
chamber section, respectively. Even at 1 x 10- 8
Torr, lifetimes are more than 10 hours. Actually
the vacuum system is designed to maintain thepressure of 10- 10 Torr under the beam-on conditions; therefore, no problems are found for thegas scattering lifetime.
(2) Touschek lifetime
When an electron collides with another electron within a bunch, a momentum change occurs.
If the momentum change exceeds a given upper
limit, the electron leaves from the stable RF
bucket and gets lost. This lifetime is inversely
proportional to the electron density within abunch: The lifetime is proportional to a bunchvolume and inversly proportinal to a bunch current. When the bunch current changes, the bunch
length also changes due to the microwave instabilty.
Lifetimes are calculated as a function of thebunch current taking the effect of bunch lengthening into account. Conditions for the calculation
are shown in Table 2. Since the broad-band
impedance ( I Z / n I) that is the cause of bunch
Table 2. Conditions for calculation of the Touschek
lifetime.
Emittance
Ey

Momentum halfaperture
L1 E / E
Bunch length 0"1

8.14 X 10- 9 7C m·rad
8.14x10- 11 7Cm·rad
2.2 X 10- 2
3.7mm ( IZ / n I = 0 n)
26.3 mm ( IZ/ n 1=50, I b=5 rnA)

1000

r------------.
a-

o

a

a

-&- IZlnl=o ohm... IZlnl=1ohm... /Zln/=5 ohms

a

a

234

5

6

Current (rnA)

Fig. 3. Touschek lifetime as a function of a bunch cur·rent.

lengthening has not yet been evaluated precisely,
impedances are assumed for the calculation of
the bunch length. 2 ) Calculated results are shownin Fig. 3. Without bunch lengthening ( I Z / n I =oohm), the lifetime is reduced to 27 hours for a 5
rnA bunch current. However, with bunch lengthening, the lifetime is almost constant even if thebunch current increases: For impedances of 1
ohm and 5 ohms, lifetimes are 100 hand 300 h,
respectively. Since the real machine will havebroad-band impedance larger than 1 ohms, theTouschek lifetime will be more than 100 h.
References
1) M.S. Zisman, S. Chattopadhyay, and 1.J. Bisognano:

ZAP User's Manual, LBL-21270 (1986).
2) Conceptual Design Report of ST A 6 Ge V SR Project(1988).

259
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-10.

Beam Stability of the 8 GeV Electron Storage Ring

K. Tsumaki, R. N agaoka, H. Tanaka, K. Yoshida, and M. Hara

In a storage ring, beam performance depends
greatly on a beam current. When the beam current is considerably low, no beam instability
occurs and the beam characteristics are readily
obtained by linear optics calculation programs
such as Synch or Magic. When the beam current
exceeds certain values, however, the beam instability occurs and bunch lengthening or emittance
growth is induced. If the beam current is further
increased, the bunch is brown up and the beam is
lost.
These current-dependent phenomena are closely related to environmental devices such as RF
cavities, bellows, and a vacuum chamber.
Because an RF cavity has narrow-band andhigh- Q impedances, it mainly induces coupled
bunch instabilities. For bellows and a vacuum
chamber, broad-band and low-Q impedances are
dominant, which correspond to the short range
wake fields inducing single-bunch instabilities.
There are several methods to avoid these coupled bunch instabilities: the setting of a higherorder mode damper in RF cavities or the employment of a feedback system or the change of an
operating point. For the single bunch instabilities, broad-band impedance should be decreasedby smoothing chamber structures or bellows.
However, the beam instabilities are inevitableeven by these cures, and the machine performance is reduced greatly by these instabilities. We
studied the instabilities by using ZApl) that is a
program for instability calculation.
(1) Impedance
Since broad-band impedance is not evaluatedprecisely, it is treated as a parameter in thecalculation of instabilities. As for the cavity
impedance, KEK cavity results 2 ) are adopted.
(2) Single bunch instabilities
Because ring broad-band impedance limits thestored current for a single bunch operation, it isnecessary to estimate acceptable impedance tostore the current of a designed value. The threshold currents Ib of longitudinal instability for abunch are calculated as a function of ring broadband impedance I Z /// n I , where Z // is the longitudinal impedance and n = W / Wo ( w is the frequency of electro-magnetic field and Wo is the

10 1 ..,..----.,.------r---------,-0SPEAR SCALING ON---+-

SPEAR SCALING OFF

10. 3 +--......--+--or---.,t---.....----i
15
10
5
o
IZI/Inl (ohms)

Fig. 1. Threshold current of longitudinal instability.

·10.,.-----~---~---~.1 +--~-_+_-__r_--+----.--_t
10
15
5
o

IZ.l.I/(2R/b 2 ) (ohms)

Fig. 2.

Threshold current of transverse instability.

angular revolution frequency of electron beam).
The threshold currents Ib of transverse instability are also calculated as a function of transverse broad band impedance I Z.L I which isconverted from longitudinal impedance using thefollowing relation.

I Z .L I =2R/b 2 I Z /;/ n I(1)where Rand b are the radii of ring and beampipe, respectively. Calculated results are shownin Figs. 1 and 2. In calculation, a SPEAR scaled
and non SPEAR scaled impedances are used. The
SPEAR scaled impedance is expressed by,

260

K. Tsumaki, et al.

1

Z ///n 1

1

Z ///n 1

1 Z /;/ n 10(2)where We = c/ b (c is the velocity of light).
The threshold currents of the longitudinal instability are the threshold values at which bunch
lengthening occurs owing to microwave instability. Microwave instability does not lead to abeam loss. Transverse threshold is the transverse
mode-coupling threshold. Above these thresholdcurrents, particles are blown up. From Fig. 2, thering broad-band impedance should be suppressed
to less than 1 ohm to obtain a beam current of
few milliampere. However, this threshold current
may be pessimistic, because the effective
impedance for a short bunch is smaller than thatof a long bunch and, in this calculation, thiseffect is not taken into consideration. A real
threshold current is probably two or three times
larger than the value obtained in this calculation.
Anyway, to obtain beam current of 3 or 5 rnA,

impedance should be reduced to less than 1 or 2
ohms.
Figures 3 and 4 show the bunch lengthening
due to microwave instability. The bunch lengthof 0.3 em increases to about 1.9 em as the current
increases to 5 rnA for the impedance of 2 ohmwith a SPEAR scaling.
(3) Coupled bunch instability
For multi-bunch operation, coupled bunch instability limits a stored current. If the growthrate is shorter than the radiation damping time,
the bunch is brown up and the beam is lost. The
growth rates of coupled bunch instabilities forthe longitudinal and transverse motions are calculated under the conditions listed in Table 1,
where the bunch lengths are calculated by assumTable 1. Conditions for calculations of coupled bunch
instabilities.
Current
Synchrotron tune
Betatron tune

100 rnA
0.009551.75
19.82
2.56 cm (22 bunches)
1.52 cm (44 bunches)
0.91 cm (88 bunches)
0.52 cm (176 bunches)
0.34 em (2,464 bunches)
32

I
Vs
Vx

Vy
10~----------~-----------'

Bunch length

CJ'j... 0.50hms... 20hms. . 60hms... 10 ohms

N umber of cell

10000 ......-----------------....,

w

....
c(

10

.1

a:
::r:
~

•

: all modes lined up•: modes de-Qed bya factor of 10•: all modes far apart

1000

100

o

Ib(mA)

a:(!)

Fig. 3. Bunch lengthening due to microwave instability
for SPEAR scaled impedance.

10
22

44

88

176

2464

NUMBER OF BUNCHES
10~-----~------,... 0.50hms... 20hms~ 60hms... 10 ohms

Fig. 5. Growth rate of longitudinal coupled bunch insta·
bility .
1000 . . . . - - - - - - - - . . . . . . - - - - .

~•: all modes lined up•....c(: modes de-Qed bya factor of 10•: all modes far apart

~ 100

a:

i= 10

~

o

a:

(!)

.1

10
Ib (rnA)

Fig. 4. Bunch lengthening due to microwave instability
for non SPEAR scaled impedance.

22

44

88

176

2464

NUMBER OF BUNCHES

Fig. 6. Growth rate of transverse coupled bunch instability.

K. Tsumaki, et al.

ing 4 ohm as impedance. Calculations are carriedout for three cases. (1) All higher-order modes indifferent cells of accelerating cavity are lined up;
the shunt impedances are 32 x Rso and Q values
are the same as for a single cell, where Rso is theshunt impedance of a single cell. (2) All higherorder modes are de-Qed by a factor of 10; theshunt impedance are 3.2 x Rso and the Q values
are Qo/10, where Qo is the Q value for a single
cell. (3) All higher-order modes in different cells
are sufficiently far apart so that there is nosuperposition among the modes in different cells;
the shunt impedance and the Q values have thesame values as in the case of single cells. The
first case is the most pessimistic assumption andthe last one is the most optimistic assumption.
Real cavities have the shunt impedances and Q
values between the two cases.
Figures 5 and 6 show the calculated growth
rates of the coupled bunch instabilities. Only adipole mode is calculated, because the growth261

rates of the other modes are much smaller thanthat of the dipole mode. Radiation damping times
for the longitudinal and transverse motions areabout 5 ms and 10 ms, respectively. Corresponding growth rates are 200/s and 100/s, respectively, and these values are smaller than the growth
rates of the longitudinal and transverse instabilities for the cases of all modes lined up and mode
de-Qed by a factor of 10. This result indicatesthat a beam current of 100 rnA will not be
achieved without the help of a feedback systemor higher order mode dampers or a Landau
cavity or any other effective cures if the de-Qing
factor is less than 10.
References
1) M.S. Zisman, S. Chattopadhyay, and J.J. Bisognano:
ZAP User's Manual, LBL-21270 (1986).
2) Y. Yamazaki, K. Takata, and S. Tokumoto: IEEE
Trans. Nucl. Sci., NS-28, 2915 (1981).

262
RII\EN Accel. Prog. Rep. 22 (1988)

V-2-11.

Design of the Sextupole Magnets for the 8 GeV Storage Ring

J. Ohnishi, E.S. Park, and S. Motonaga
A Chasman-Green magnet lattice will beapplied to the 8 Ge V storage ring. In this type oflattice, 7 sextupole magnets are used per one cellfor chromaticity and harmonics correction. l )These sextupole magnets have two distinctive
features. One is that some sextupole magnets
have asymmertrical yokes. Since this ring isutilized as a synchrotron radiation source, a lightbeam is extracted from bending magnets andinsertion devices at a small angle and is passed
through a part of the magnets located downstream. Therefore, yokes are designed to extend
in one horizontal direction in order to makeroom for the light beam. Another feature is thatthe sextupole magnets include the capability toprovide horizontal and vertical steering fields.
The configuration of the sextupole magnets isshown in Fig. 1 and the principal parameters arelisted in Table 1. The magnets can be operated atmore than 360 T 1m2 for the maximum strengthof sextupole field. The magnet yokes and poles
are constructed from 0.5-mm thick silicon steellaminations. One magnet consists of six sections.
They are assembled after all coils are fitted tothe pole and the yoke. The bore diameter is 110
mm decided from the size of a beam chamber.
840

Table 1. Sextupole parameters for the 8 Ge V
storage ring (48 cells).
N umber of magnets
Physical length
Magnet aperture radiusGood field radiusStrength E ", max
Number of turns per pole
Current
Current density
Conductor size
V oltage drop per magnet
Power
Water flow
Water pressure drop
Water temperature rise336
0.45 m55.0 mm40.0 mm
360 T / m2
18445 A
3.5 A / mm 2
10 x 14 mm 2 ,4>4 mm
10.0 V
4.5 kW
1.1 ll min
2.0 kg / cm 2
lOoe

w
~

«
....I

w

1.005
1.004

!5.

1.003

x

1.002

~
z
w

a:

1.000
0.999

w

0.998

oQ.

0.997

:::I

0.996

t<w

II)

A

'\.
"\. ..

1.001

~

....I

'"

./ \.
I

........,

~
.~
. .

\

\

,

\
\

I

0.995
-6

-5

-4

-3

-2

-1

0

2

3

4

5

6

POSITION (em)Fig. 2. Calculated sextupo!e field distribution of the
sextupo!e magnet on a median plane normalized by
E " =360 T / m 2 at x= - 0.5 cm.

Fig. 1. Cross-sectional view of the sextupole magnet
with steering elements. S: Sextupole coils, H:
Horiz. steering coils, V: Vert. steering coils.

The contour for all pole tips is the same, r3cos38
with shims. The width of poles and yokes isdesigned thick enough so that the reluctance iniron may be espesially small because the dipole
field for steering is excited additionally. The
coils for the sextupole field are wound with 18
turns per pole of OFC hollow conductor.
The configuration of an iron yoke was decided
from the numerical calculation of field distribution using a second dimensional code LINDA.
The calculated distribution of the normalized
sextupole field on a horizontal median plane isshown in Fig. 2. The field lines are shown in Fig.
3. The difference in the field strength between
the left- and right-hand sides which is generated

]. Ohnishi, et at.

Fig. 3. Field lines of the asymmetrical sextupole
magnet.

by the asymmetrical yokes could be suppressed
to within 2 X 10- 3 , small enough, by choosing agood thickness for the asymmetrical parts of theyokes. The shape of radial shims was also
optimized so that a good field region can extend
as wide as possible. The sextupole field is madestronger around both sides of the aperture
because its integral value along the beam direction is expected to be smaller than in the central
Table 2.

263

region.
These sextupole magnets have extra coils forproviding horizontal or vertical dipole fields
which steer a beam in order to correct the closed
orbit distortion. Two of the seven sextupole
magnets in one cell provide horizontal dipole
fields while another four provide vertical ones.
Only the one remaining magnet operated withthe strongest sextupole field have no steeringfunction. It was cheked by computer tracking
simulation 2 ) that these six sextupole steering
elements and six usual steering magnets cancorrect the closed orbit distortion to be enoughsmall. Then it was found out that the maximum
required kick angle value on the beam is about 1
mrad.
The vertical dipole fields for horizontal steering is provided by excitation of the respective
upper and lower three poles with opposing polarity. The six vertical dipole coils of the magnet

Parameters of steering coils in sextupole magnets (48 cells).

N umber of magnets
Physical length
Kick angle
Peak field
N umber of turns per pole
Current, max.
Current density, max.
Conductor size
Voltage drop per circuit
Power per circuit

are powered by two current sources. One source
powers two series coils around the two poles
which face each other along the perpendicular
direction and another powers the other four coils
in series. The best field quality is generated byadjusting the current ratio between these twocircuits. In contrast, the horizontal dipole field isprovided by excitation of the two left-hand sidepoles with one polarity and the right-hand side
ones with opposite polarity. For the excitation,
the four series coils which are wound about
return yokes are used. Table 2 shows the parameters of the sextupole steering elements. Theseelements can be operated up to 0.059 tesla inbipolarity as a maximum strength of the field.
This value gives a 1 mrad kick angle to the
beam.
Figure 4 shows the distribution of horizontal
and vertical dipole fields Bx(y), By(x) on eachsymmetrical plane. This result was caluculated

Horiz. steering(2 circuits)

Vert. steering(1 circuit)

192
0.45 m1 mrad
0.059 T
100,4042 A
1.7 A/ mm 2
5x5 mm 2
9.6, 7.7 V
0.40, 0.32 k W

960.45 m1 mrad
0.059 T90
42 A
1.7 A/ mm 2
5X5 mm 2
14.7 V
0.62 kWby the LINDA. The distribution of the vertical
dipole in the figure was obtained by exciting thetwo central poles 2.5 times more strongly than

w

>
t=
c(

....

w

!:.

...:z:CJ

z

w

...a:
U)

....cw
u:

1.10
1.08
1.06 I - - - e - 1.04 I-- ----.--/

jhoriz. steer/

vert. steer
).

1.02
1.00
0.98

"1!1-, .~.~...r;r"'"~...........

0.96
0.94

"

0.92
0.90
0.0

0.5

1.0

1.5

2.0

2.5

1\

3.0

'\
3.5

4.0

POSITION (em)Fig. 4. Dipole field distribution calculated for horizontal and vertical steering in the sextupole magnet. By (x) / By(x=O) on a y =0 plane for horiz. steering and Bx(y)/Bx(y=O) on x=O for vert. steering
are shown. The By(x = 0), Bx(y = 0) are both 0.059 T.

264·

J. Ohnishi, et al.

the other poles. In this calculation the main coils
for the sextupole field are not excited. However,both sextupole and dipole coils are simultaneously excited in real magnets. The field distribution
is expected to be different from a simple superposition of dipole and sextupole fields because of
the non-linearity in iron magnetic properties.
Therefore, we have to calculate multipole fieldcomponents from the sextupole magnets withsteering elements under realistic conditions.
Furthermore, we need to execute beam tracking
simulation by using the result and make sure thatthe undesirable multipole field components are

small enough to obtain the required dynamic
aperture size. These analyses are the subject of
the study from now.
At present, we are designing a sextupole magnet mechanically . We are scheduled to constructa model magnet and measure its magnetic qualities.
References
1) R. N agaoka, H. Tanaka, K. Yoshida, K. Tsumaki,
and M. Hara: This Report, p. 227.
2) H. Tanaka, R. N agaoka, K. Tsumaki, K. Yoshida,
and M. Hara: This Report, p. 231.

265
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-12.

RF System for 8 GeV SR

T. Y oshiyuki, T. Kusaka, and M. Hara

In previous work, 1) we designed the RF systemfor 6 Ge V SR. We have now chosen to set thedesign energy of this SR facility at 8 GeV. This
report describes an approach to designing the 8
Ge V RF system.
The RF design parameters for the storage ringare listed in Table 1. Several advantages inmachining cavities and the technical and commercial development for almost all the circuit
devices in TRISTAN and PF (KEK) 'make thechoice of the operating frequency of around 500
MHz. The nominal RF frequency is determined
to be 508.58 MHz, the same frequency as TRISTAN, and the harmonic number is 2,424
There are three kinds of energy losses for the
storage ring. The first is due to synchrotron
radiation from dipole magnets and amounts to
8.3 MeV at 8 GeV beam energy and the magnetic
strength of 0.61 T. The second is due tosynchrotron radiation from insertion devices anddepends on the exact distribution of undulators
and wigglers and their characteristics. Since
insertion devices aren't designed yet, the loss isoverestimated at 3.2 MeV. The last loss is calculated from the average beam current and thetotal impedance for higher-order cavity modes
Table 1.

RF parameters of the storage ring.

Beam energy
Circumference
Bending radius
Momentum compaction factor
Natural energy spread
Radio frequency
Harmonic number
Synchrotron radiation loss per turn
Energy loss for insertion devices
Parasitic energy loss per 100 rnA
Nominal RF voltage
Maximum RF voltage
Shunt impedance
Quantum lifetime
N umber of cells
Radiation damping time
Beam current
Beam power
Cavity power
Klystron power
N umber of klystrons

8 GeV
1,428.87 m
43.75 m1.373 X 10- 4
0.3%
508.58 MHz
2,424
8.3 MeV
3.2 MeV
0.5 MeV
12 MV
16 MV

and vacuum chamber components except thecavity. These impedances depend on the bunch
length and the conditions of the bunch operation.
The longer the bunch length, the smaller theenergy loss. The loss also decreases with thenumber of bunches. The impedances for cavities
and the vacuum chamber are important forenergy loss and beam stabilities. Here this loss isestimated at 0.5 MeV for multi-bunch operation.
Since total energy loss per turn amounts to about
12 MeV, the RI" system for the storage ringshould be capable of providing 12 MV.
An overvoltage is required for a long quantum
lifetime, which is also a function of a momentum
compaction fa<!tor and a beam energy spread
besides the main RF parameters. The momentum
compaction factor and the beam energy spreadare 1.373 x 10- 4 and 3 x 10- 3 , respectively. The
overvoltage factor of 1.33 gives more than one
day for the quantum lifetime when the accelerating voltage is 12 MV. As a result, the maximum
peak voltage in the cavity should be 16 MV.
The generator power Pg is the sum of thecavity power dissipation Pc, the power transferred to the beam Pb , and the reflected power Pro
Here, we estimate these powers when the average beam current 10 is 0.1 A and the shunt
impedance is 22.5 Ma/m. The cavity power percell is limited to about 50 kW due to the problems
in voltage breakdown and a vacuum. The cellnumber is thus determined to be about 35. In thecase of 35 cells, the total cavity power Pc
Power variation-a- Pg (MW)..... Pb (MW)..... Pc (MW)..... Pr (MW)22.5 MO/m>1 day'""35
3.17xlQ-3 s
100 rnA
1.08 MW
1.20 MW
1MW
4

20

40

60

80

100

120

Beam current (rnA)

Fig. 1.

Power variations as a function of beam current.

266

T. Y oshiyuki, et at.

becomes 1.08 MW and the beam power Pb 1.20
MW. From the viewpoint of the symmetry ofarrangement and the margin of power, four
klystrons will be set symmetrically around thestorage ring. Each power variation is shown in
Fig. 1 as a function of the beam current.
Four straight sections of each 6.5 m long will
be needed for the arrangement of the RF cavities.
In designing the cavity, two types of cavity structures are investigated: one is a single-cell cavity

and the other is a multi-cell cavity. The singlecell cavity has fewer higher-order modes thanthe multi-cell cavity. It is also easier to analyze
the properties of the resonant modes. Since thepower is fed to each cell, the power per cell getslarge; therefore, the cell number could be reduced
and an attainable beam current will increase.
Since each cell has its own cavity component,
however, the system needs more components andwill be costly and complicated. Compared with

Table 2. Comparison between a single-cell cavity and a 3-cell cavity.
Cavity type

Single-cell

3-cellCell number
Number of units
Arrangement of units

32
32
8unlts X 45 . 5

Pc / unit(Pc+ Pb)/ unit

37 kW
75 kW
1
0.2A

42
14
4unlts X 35 . 52unlts X 15 . 5
21 kW
150 kW
1
0.15A

Number of coup'ers/ unit
Imax

(48)
(16)

(4unlts X 45 . 5 )(17 kW)(125 kW)(1)(0.2A)

s.s: straight sections, ( ): another case for a 3-cell cavity.

the single-cell cavity, the multi-cell cavity haslarge shunt impedance per cavity length and theconfiguration of the transmission lines will be
simple, but it is liable to cause beam instabilities
due to multiple higher-modes. In the case of themulti-cell cavity, both 3-cell and 5-cell cavities
are studied. In the 5-cell cavity, two RF windows
are needed to fill the power into the cavity,
because of the limit of power per window ofabout 200 kW, but the power cannot be fed wellto the cavity through two windows owing toreflection and transmission of the power. Therefore, for the storage ring, the 3-cell cavity ispreferable to the 5-cell cavity. The relations of
the cell number and the power for the single-celland the 3-cell cavities are shown in Table 2. The
final specifications of the cavity will be determined after the tests of a 1/ 6-model cavity and alife-sized model cavity 2,3) and high power tests asmentioned later.
A higher harmonic RF system may be combined with the fundamental RF system for the
storage ring. Adjustment of the slope of thesuperposed RF wave at the bunch center leads tocontrol of a bunch length and a spread ofsynchrotron frequency. The resulting large
spread of synchrotron frequency across thebunch together with the reduced peak current
eliminates longitudinal coupled bunch instabilities and the head-tail effect. The third harmonic
system is considered here and fixed at a fre quency of 1,525.74 MHz. Figure 2(a) shows thesuperposition of RF waveforms in the 508.58

Uol tage (IV)
3rd Harmon i ? So,JStem
Phase Funct Ion

VRF1 + VRF3,.F ;.•::----..... . /16

I / """ .\.

VRF1! ,/122.5"-- ··\··".V.
qls.0

\

3 .2
\.

/1

\"

,'1

\\.\

h---·

~ i

qls

\\

/

_~-/;;--,I!-f'l--',I,.....\. .-.

-----,!'----+-·
.

I i

//i

\

508 . 58 MHz----'\i-',-----,'----+---,-Ph~;~grees)---....;.
/ I+·i ''Ps3

i 110.80VRF31525.74 MHz(a)

Potent i'a/
3rd Harmon i c System
Potential Function

i,'

! !~

i;

.i i
1 f

i;

j!

!L
,
- With 3rd Harmoni c!

,,W -- without 3rd Harmon i c
" i

.,/

I ,/
//
..... .

ql - Cfis Phase (degrees)(b)Fig. 2. 3rd harmonic RF system; a) RF waveforms, b)
potential functions with and without harmonic system.

267

T. Yoshiyuki, et al.

MHz and the 1,525.74 MHz systems. Figure 2(b)shows the potential functions with and without
the properly adjusted 3rd harmonic system. It
turns out that it is reasonable to utilize the 3rd
harmonic system to get a sufficiently long bunch
length. Table 3 shows the typical parameters of
the 3rd harmonic system. When the fundamental
RF peak voltage is 16 MV, the 3rd harmonic RF
peak voltage comes to 3.23 MV. As for the cavity, 5-cell cavities with an on-axis coupled structure are applicable. The shunt impedance isabout 30 Ma/ m. The cell length is A/2 (9.9 cm),where A is the wavelength of the 3rd harmonic
RF. Four 5-cell cavities would be considered toprovide the impedance of about 60 MO. In orderto produce the necessary voltage, a total power

Table 3. Parameters of the 3rd harmonic RF system forthe storage ring.
Frequency
N umber of cavities
Number of cells per cavity
Peak voltage of the 3rd harmonic RF
Peak voltage of the fundamental RFv*
k**Shunt impedanceCavity power
it / 2 (it: wavelength of RF)
Phase angle (in terms of 508.58 MHz)1,525.74 MHz
45
3.23 MV
16 MV
0.75
0.202
30 MO/m
176 kW
9.9 cm110.8 degrees*v = (operation voltage)/ (peak voltage of the fundamental RF system)* * k = (peak voltage of the 3rd harmonic RF system) /(peak voltage of the fundamental RF system)

Stage 1
Stage 2

Fig. 3.

Block diagram of high power test.

of 176 k W would be required.
N ow, we plan high power tests in order todetermine the final specifications of the RF system for the storage ring. The block diagram isshown in Fig. 3. The tests are performed in twostages. In the first stage, the experiments of a
1-MW klystron and a transmission line are conducted to supply the high power stably. The
control system for the klystron will be established by using a dummy load. Several test cavities for high power will be examined in the nextstage. These tests give design limitations such as
the maximum accelerating voltage and the maximum power coupled through the RF window.
References
1) T. Yoshiyuki, T. Kusaka, and M. Hara: RIKEN
Accel. Prog. Rep., 21, 235 (1987).

2) T. Kusaka, T. Yoshiyuki, and M. Hara: This Report,
p. 27l.

3) T. Kusaka, K. Inoue, T. Yoshiyuki, A. Miura, and M.
Hara: This Report, p. 268.

268
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-13.

500 MHz Model Cavities for the 8 GeV SR Ring

T. Kusaka, K. Inoue, * T. Y oshiyuki, A. Miura, ** and M. Hara

In the 8 Ge V storage ring, it is planned to use
a 508 MHz RF system. Two model cavities of asingle-cell type and a 3-cell type have been fabricated to evaluate their electromagnetic properties and determine the specifications of a practical cavity. The inner shape was determined on
the basis of numerical calculations!} and measurements of a 1/ 6 scale test cavity.2) The resonant frequency of the fundamental mode isdesigned to be 500 MHz in the single-cell cavity.
The 3-cell cavity is shown in Fig. 1. Figure 2
shows the disk configuration with re-entrant
nose cones and two inductive coupling slots. The
single-cell cavity is assembled by using the center cell of the three cells and two end plates. The
fabrication process of the model cavity was
divided into four steps as follows. RF characteristics were measured in each process.
In the first step, the model cavities were machined out of 6061 aluminum alloy. The overallmachinery accuracy was within±O.l mm. In thiscase, the maximum deviation of the resonant
frequency of the fundamental mode is calculated
to be about 0.6 MHz in the single-cell cavity.
Each cell has the same diameter and small holes
for measuring probes. Resonant frequencies andQ-values were measured by the reflection
method with a network analyzer. Eighteen resonant modes were observed below 1.5 GHz in the
single-cell cavity. Four modes were measured
precisely because they were found to have highimpedance values from HAX 3 ) and URMEL4)

Table 1.
Mode

™o 1 0TMoll
TM 110
TMlll

Fig. 1.

Photograph of the assembled 3-cell cavity.

oin~~~~~~~L-_ _~~~~~_ _ _ _~Fig. 2. Disk configuration withre-entram nose cones
and inductive coupling slots.

calculations. Table 1 shows the results of measurement and calculation. The longitudinal andtransverse impedances were computed from theelectromagnetic field distribution along thebeam axis. The method of calculation is described in Ref. 5. The electric and magnetic field

RF characteristics of the single-cell cavity.

Frequency(MHz)

Unloaded Q

R II (Mn) or
R -.l (Mn m - l)

Exp.

Calc.

Exp.

Calc.

Exp.

Calc.

499.6
747.2
844.8
1,050.4

500.5
749.2
844.1
1,053

22,00018,30028,90021,00026,00022,00036,00028,000

5.1
0.99
9.0
13

6.0
1.2
14
16

* Kobe Steel, Ltd .
•• College of Humanities and Sciences, Nihon University.

T. Kusaka, et at.

269

Table 3. RF characteristics of the 3-cell cavity with"flat" 7Z'-mode.
•••••• measured

Mode

Frequency(MHz)

Unloaded Q

R // (MO) or
R ..L (MO m- I )7Z'™ o I 0 7Z'/ 2

491.0
492.6
495.7

19,90022,40022,00015
0.1
0.0™oII 7Z'/ 2
7Z'

719.9
737.8
743.6

17,20020,00019,800

0.4
1.9
0.3

7Z'
TM 11 0 7Z'/ 2
0

830.1
834.3
840.3

24,80029,00030,000

0.3
8.5
13

°

1,004.2
1,024.0
1,047.4

17,30017,60021,500

19
0.0
4.1

°0
0

~

TMlll 7Z'/ 2
7Z'

Fig. 3. Measured electric field distribution of the accelerating mode with computed result in the single-cellcavity.

Table 2. RF characteristics of the 3-cell cavity wheneach cell has the same diameter.
R // (MO) or
Unloaded Q R ..L (MO m- l)

ModeFrequency
(MHz)

7Z'
™o I 0 7Z'/ 2
0

492.7
496.6
498.0

20,10021,40021 ,600

12
0.0
2.1

0
™ol1 7Z'/ 2
7Z'

719.6
736.3
742.2

16,90018,60019,300

0.37
1.8
0.32

7Z'
TM 1IO 7Z'/ 2

832.8
840.9
844.2

24,70026,70024,6002.8
129.1

1,005.1
1,026.2
1,048.2

17,30018,60021,500

19
0.1
4.4

°0
TMIII 7Z'/ 2
7Z'

distributions were measured by a perturbation
method. 6 ) A metal sphere and a teflon sphere
whose diameters were 20 mm were used as perturbing objects. Figure 3 shows the longitudinal
electric field of the accelerating mode in the
single-cell cavity. The electric field E is normalized so that the integral of I E 12 over the cavity
is unity. The measured values agree well withthe calculated values. In the 3-cell structure,
triple modes were examined, whose phase shifts
per cell were 0, 7!/ 2, and 7!. The results are listed
in Table 2. In the accelerating mode, which was
the 7! mode of the fundamental mode, the fieldratio of the center cell to the end cell was measured to be about - 2.3. During one to threeminutes of measurements, the temperaturechanges of the cavity led to resonant frequency
drifts. It was compensated numerically by assuming the drifts were in proportion to time.
In the second step, the radius of end cells wasenlarged to make a "flat" electric field in the
3-cell cavity. The cutting allowance of the cellbody was calculated to be 3.2 mm by substituting
the measured resonant frequencies into an equivalent circuit. 2 ) The results are listed in Table 3.
The shunt impedance of the accelerating modeincreased from 12 MO to 15 MO, which wasnearly three times as high as the one in the
single-cell cavity. The coupling factor between
adjacent cells was calculated to be 1.3% frommeasured frequencies.
In the third step, ports were machined in eachcell. The center cell had four ports which wereused for an input coupler, a frequency tuner, anddamping couplers. Axially-asymmetric modes
were split into two orthogonal modes because
the degeneracy was broken by the ports whose
diameters were different from each other. The
direction of the field was measured by rotating asmall flat metal plate at the center of the cavity.
In this step, the Q-values in the higher-ordermodes were damped by the gap between a filler
and a port. A damping factor of 4 was measured
in a TMll1-like mode. The optimization of thegap size will be necessary to increase the damping factor and reduce the effect of higher-ordermodes on electron bunches.
The surface roughness is related to the surface
resistance, which is proportional to the power
dissipation in the cavity. In the final step, theinner surface of the cavity was buffed to increase

270

T. Kusaka, et al.

the Q-value. The roughness was improved from 3.urn to better than 0.5 .urn. As a result, the Qvalue in the accelerating mode is increased byprototype of cavity for tests using a I-MW
klystron will be designed on the basis of thepresent results.

5%.
The impedances of the single-cell cavity andthe 3-cell cavity were measured in four modes.
Although the shunt impedance of the accelerating mode in the 3-cell cavity was almost threetimes as high as the one in the single-cell cavity,
the maximum impedance of the higher-ordermodes was about 1.5 times as high as that of thesingle-cell cavity. A damping coupler will be
developed to suppress the impedances of higherorder modes and increase the threshold currentof coupled-bunch instabilities. Furthermore, aReferences
1) T. Kusaka, T. Yoshiyuki, N. Kawasaki, and M. Hara:

RIKEN Aeee!. Prog. Rep., 21, 237 (1987).
2) T. Kusaka, T. Yoshiyuki, and M. Hara: This Report,
p. 271.
3) M. Hara, T. Wada, A. Toyama, and F. Kikuchi: Sci.
Papers I.P.C.R., 75, 143 (1981).
4) T. Weiland: Nuel. Instrum. Methods, 216, 329 (1983).
5) Y. Yamazaki, K. Takata, and S. Tokumoto: KEK
80-8, Aug. (1980).
6) L.e. Maier, Jr. and J.e. Slater: ]. Appl. Phys., 23, 1(1952).

271
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-14.

Study of Multi-Cell Cavity with Inductive Coupling Slots
for the 8 GeV SR Ring
T. Kusaka, T. Y oshiyuki, and M. Hara

It is necessary for RF cavities in the 8 GeV SR
ring to accelerate electrons with high efficiencyof RF power and beam stability. In · general,cavities of a standing-wave type used in electron
machines are classified into single-cell structuresand multi-cell ones. Multi-cell cavities have an
advantage of higher shunt impedance per unit
length than single-cell cavities and the RF system using multi-cell cavities includes a simplertransmission line from an RF power source tocavities than the RF system using single-cellcavities. However, the design of a multi-cellcavity is more difficult because of a coupling
problem between cells and its dispersion property. Many types of multi-cell cavities have been
operated in the 7C or 7C/2 mode. In the 7C mode,
higher shunt impedance is achieved, but tuning
errors perturb the electric field more sensitively
than in the 7C/2 mode as the cell number of acavity increases. I) Because the cell number needs
to be small in the 8 GeV storage ring,2) a model ofa 3-cell 7C-mode cavity with two inductive coupling slots was fabricated to study RF characteristics quantitatively. This report describes anapproach to the calculation of the behavior of
the 3-cell cavity and the comparison with theexperimental results.
An equivalent circuit of the 3-cell cavity withinductive coupling slots is shown in Fig. 1,3) inwhich C is the capacitance between the end
plates and Land L' are the inductances of theouter regions where the magnetic field is predominant. Inductive coupling between cells is represented by a parallel inductance Le. The coupling factor, which is the ratio of a mutual inductance between cells to a self-inductance of a
L'

L

L'

c

c

c

Fig. 1. Equivalent circuit for a 3-cell cavity withinductive coupling slots.

Fig. 2. 1/6 scale test cavity with several kinds ofcoupling disks.

o

g 4
u..
01

.=

Q.
~

o

2

o+-~~--~~~--~~~~

30

40

50

Slot Angle6070e (degree)

Fig. 3. Coupling factor as a function of slot angle inthe 1/ 6 scale test cavity.

cell, is an important parameter to design amulti-cell cavity. A 1/6 scale test cavity was
fabricated to investigate the influence of coupling slots. Several kinds of coupling disks
shown in Fig. 2 were examined. The result of
measurement is shown in Fig. 3. The coupling
factor increases as the slot angle increases, but
the shunt impedance decreases because of thepower dissipation in the slots. 4 )A life-sized model cavity was fabricated basedon the experimental results on the 1/6 scale test
cavity. The cavity structure is described in Ref.
5. Two coupling slots whose azimuthal angle is
45 degrees are machined to achieve more than
1% coupling with suppressing the extreme drop272

T. Kusaka, et al.

i 5 +--+--f--1&--1f---/lor--+--+---1'E-~ 0 +--G-i---HF-~~~--+...m-~-5+--+--~~~~--+-~-1 0 +--r--i-~~.....--lr--r~--r-+~-I
-60
-40
-20
0
20
40
60

- 1 0 +-.....-i--r--t---.,........,I---o--+--r-+~--1-60 -40
-20
0
20
40
60
z (cm)z (cm)

Fig. 4. Electric field distribution measured on the
beam axis in the accelerating mode, when the 3cells of the full-scale model cavity have the same
diameter.

of the shunt impedance. When three cells havethe same diameter, the electric field distributionof the accelerating mode is shown in Fig. 4. The
electric field ratio of the center cell to the end
cell is - 2.3. On the other hand, applying theKirchhoff's law to the three loops in Fig. 1, one
obtains following equations.
UwL' + l/jwC) i1+ jwLe (i1 - i2)=0
UwL+ l/jwC) i2+ jwLe (2~ - i1 UwL' + l/jwC) i3+ jwLe (h - i2)=0

(la)

i3)=0

(lb)
(Ie)

Solving the eigenvalue problem, we have threeresonant frequencies;
W = {( Wa+ Wa')+3 We± I( Wa- Wa')2+2( Wa- Wa') We+9 We2}
/2
(2a)
(2b)
W = Wa'+ We
W=I/w 2 ,Wa = 1/ Wo 2 = LC,
Wa' = 1/ WO'2 = L' C,
andWe = 1/ we2 = LeC.
The current ratio r = i2/ i1 in the 7! mode is givenbyr = {( Wa' -Wa) - We
- I( Wa- Wa')2+2(Wo - Wa') We+9 W/}
/2 We
(3)

When L is equal to L', the ratio r is computed tobe - 2, where the minus sign means that thedirection of the current flow is opposite. Compar-

Fig. 5. Measured electric field distribution of the
full-scale 3-cell cavity with a "flat" 11: mode.

ed with the measured ratio - 2.3, it is found that
L is larger than L'. By substituting the measured
three frequencies of the fundamental modes into
Eqs. 2, the value of L' is calculated to be 0.997 L.
In the multi-cell cavity, it is important toobtain a "flat" 7! mode, where the electric fieldstrength is the same in all cells, in order toachieve high efficiency of the acceleration andstabilize the operation. The condition of a "flat"
7! mode is obtained by substituting i1 = - i2 = i3
into Eqs. 1, that is L' = L + 2L e. As a result of
calculation, the resonant frequency of the end
cells wo' / 27! must be lowered by 4.12 MHz. Afterthe end cell radius is enlarged by 3.2 mm, theelectric field distribution of the accelerating
mode is changed as is shown in Fig. 5. The
electric field ratio is improved to be -0.986 andthe shunt impedance increases by 25%. The resonant frequency of the accelerating mode is measured to be 490.97 MHz, which is nearly equal to
the frequency calculated with the equivalentcircuit. The coupling factor, which is given by
x =2Le/(L+2L e), is calculated to be 1.3% withthe "flat" 7! mode. Throughout the experiment of
the 3-cell cavity, the analysis using the equivalent circuit is useful in the fundamental mode.
Further, it is expected that this design method
can be applied to a 5-cell or 7-cell cavity for thebooster synchrotron.
References
1) P. B. Wilson: IEEE Trans. Nucl. Sci., NS-16, 3, 1092

(1969).
T. Yoshiyuki, T. Kusaka, and M. Hara: This Report,
p.265.
3) J. R. Rees: PEP-255, Oct. (1976).
4) T. Kusaka, T. Yoshiyuki, A. Miura, and M. Hara:
1989 Particle Accelerator Conf., D33.
5) T. Kusaka, K. Inoue, T. Yoshiyuki, A. Miura, and M.
Hara: This Report, p. 268.
2)

273
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-15.

Calculation of the RF Electromagnetic Field
for 8 GeV SR Ring Components

T. Kusaka, A. Miura,* T . Wada, and M. Hara
In designing an 8 Ge V storage ring, it is necessary to investigate the RF characteristics of ringcomponents, especially high-Q components, suchas a cavity and bellows. Computer programs
MAX3D and H2DB using a finite element method
were developed to evaluate RF properties in twoand three-dimensional analysis. 1,2) We calculated
the changes in resonant properties by a frequency tuner in a cylindrical cavity and theshielding effect of a test bellows with these
programs.
(1) Three-dimensional analysis of a cylindrical cavity with a tuner
A frequency tuner is necessary to adjust theresonant frequency of an accelerating cavity formechanical errors in the fabrication, the thermal
effect due to the power dissipated in the cavity,
and the phase correction between a generator
voltage and an accelerating voltage. A plunger
type of tuner mounted in the cylindrical cavity is
tested. Because of the tuner structure, it is necessary to solve a three-dimensional problem.
Figure 1 shows the cavity structure. The crosssectional area of the tuner is 19.2 cm 2 • The halfcavity is divided into 16 elements along the longitudinal direction and 9 elements along the radial
direction as shown in Fig. 2. The ™o 1 0,
TMo 1 1, TMI 1 0 , and TMI 1 1 modes are studied
precisely because they are found to have highimpedance values from calculations. In the caseof no tuner, the calculated resonant frequencies
are listed with analytical values in Table 1. The
error is estimated at less than 1.3% below 1 GHz.
The CPU time is about 26 minutes for a F ACOM
M -780 computer.
When the tuner is inserted, the calculation iscarried out by eliminating the corresponding
elements of the tuner from the region underanalysis. An axially-asymmetric mode is split
into two orthogonal modes suffixed V and P,
because the degeneracy is removed by the tuner.
The changes in the resonant frequency are
shown in Fig. 3. When magnetic energy is stronger than electric energy at the tuner position, the• College of Humanities and Sciences, Nihon University.

o
o

'"

Fig. 1. Structure of a cylindrical cavity with atuner.

'>r-/~~~ ~ ~;:::~ ~

.--

-d~

~

/' !/

--

/ /' / / 1/ / // // // / / / // V V / / V 1/ / /v V V / / 1/ / / // V V / / / / / / /V V . / L I / / / // V V / /: / / / / / / / / / 1 / / / // / / / / / / / / / / / //1/ / / // / / / / / / / / / / / ./ / / V / // / / /' /' / / / 1// / / V / / V V // / / /' / / / V / / / V V V V V V // / 1/ / / / V V V / / V V V V V V V/ / / / / / V V V/ / V V V / V V V/ / / / / / / / 1 / / / / / / 1 / / 1/1/
V / / V / / V V lL"L / V V / /1/ / // / / / / / / / 1//1/ / 1/1/ / / 1/1/
V / / V / / V V VVV V V V / V V V
V / / V / / V V V/VV V / /V V V
/
/

/
/

/
/

/
/

/
/

/
/

/' /
/ /

/
/

Fig. 2. Subdivisions of a half cylindrical cavity.

Table 1. Comparison between calculated resonant
frequencies and analytical ones.
Mode™o 1 0™ oil

TM 1 10 TMl ll

Calculated
frequency(MHz)499.31707.42793.78950.96

Analyticalfrequency(MHz)498.88706.07794.87938.88

274

T. Kusaka, et al.
20~------------------~

TM010... TM110P-0- TM110V.... TM111V
o(l)-

'N 2

N ·20

J:

J:

<3

~ ·40

~

~
Uo1

·60
·1 +---.---,r-......--.,...----,.---,....-..,..~o2·80 -t---.-----,r-...,......---r---.--......----r---Io
8

Tuner Posillon (cm)(a)

Tuner Posillon (cm)(b)

Fig. 3.

Variation of resonant frequencies as a function of tuner position.

100 ~o<::::::::-------------.

50(a) TM111V(b) TM111P

Fig. 4. Three·dimensional electric field distribu·
tion of orthogonal TMI 1 1 modes. Bars indicate
the strength and the direction of the electric fieldat each element.

-50-100 -t-----.------,.-----y-----=~
-0.15
0.00
0.15

z

(m)

Ez (Tuner Position 0 em)- - El. (Tuner Position 0 em)~ Ez (Tuner Position 5 em)--0- El. (Tuner Position
5 em)

-0-

resonant frequency increases, and vice versa. The
calculated results agree with this theorem. The
resonant frequency of the TMo 1 0 mode goes up
by about 0.8 MHz with a stroke of 5 cm. This
result agrees with the experimental result using
a 1/6 scale test cavity by considering the scaling
factor.
As a typical result of the field calculation, theelectric field distributions in the TMI 1 Iv andTMI 1 Ip modes are shown in Fig. 4, when thetuner is inserted by 5 cm. Next, the distributionof the RF electromagnetic field along the beamaxis is examined. The accelerating electric fieldin the TMo 1 0 mode hardly changes by the tuner
insertion. When the tuner is inserted by 5 cm, thedeviation of the accelerating field is less than
1%. In the TMo 1 1 mode, a transverse electricfield is induced which causes beam deflection.
Figure 5 shows the strength of the electric fieldalong the beam axis. The TMI 1 1 modes shown
above also have transverse fields. The effect ofthese fields in higher-order modes on the beam
motion can be investigated on the basis of thesecalculations. From now on, the three-dimensional analysis will be applied to a model cavity
for the 8 Ge V SR ring.
(2) Two-dimensional analysis of a test bel-

Fig. 5. Electric field distribution of TMo 1 1 modeon the beam axis.

E
E

a

E
E
o
N

40mm

10mm

(a)

(b)

Fig. 6. Two·dimensional model of a test bellows.
(a), a quarter of a bellows; (b), mesh diagram.

lows
A new type of bellows is designed to get an
electrical connection between an RF contact andT. Kusaka, et at.

275

Fr.. l0.490GHz

Fr:4.2S34GHz

Fig. 7. Calculated magnetic field lines for TM modes.

flanges. 3 ) It includes an inner conductor withslots along the beam axis and an outer conductor
which is a conventional type of a bellows. A
quarter of a cross section shown in Fig. 6 is theregion under analysis. The total number of elements is about 4,500. A strip of the inner conductor is 1 cm wide and its thickness is assumed to
be zero. The width of a slot is 1 mm.
The electromagnetic wave induced by a bunched beam can propagate along the inner region.
The frequency of the wave depends on the bunchshape and the number of bunches in the ring. The
propagating mode is mainly a transverse magnetic mode because the image current of thebeam flows along the chamber. The magnetic
field lines and the cutoff frequencies of TM
modes are shown in Fig. 7, when the natural
boundary condition is imposed on the axes of
'C

100

~
u

.;:

U
.!!!
CI)

iii

.:
'C

a

.,;

strip thickness
0.0 mm

0)

I:

~

--

CI)

.~

References
1) M. Hara, T. Wada, A. Toyama, and F. Kikuchi: Sci.

0.1 mmPapers I.P.C.R.} 75, 143 (1981).

:§
CI)

a:

symmetry. The magnetic fields hardly change
under 15 GHz compared with the results of noslots. At higher frequencies, however, a mode in
the inner region couples a mode in the outerregion. It might cause an energy loss of an electron and overheating in a bellows.
To avoid the coupling, the reduction in the gap
between conductors is considered. When the gap
is shortened from 10 mm to 5 mm, the frequencyof the mode coupling goes up above 19 GHz. It isalso effective to increase the thickness of theinner conductor. Figure 8 shows the distributionof the longitudinal electric field along the horizontal axis. When the thickness of the strip
increases from zero to 0.1 mm, the leakage of the
field is decreased by 86% at a frequency of 15.9
GHz.
The two-dimensional electromagnetic field ina bellows is calculated. Since the bellows has afinite length along the chamber, it is necessary toextend the calculation into three-dimensional
analysis. Furthermore, an experiment is planned
to measure the properties of the bellows by transmitting a current pulse through a thin wire along
the beam axis. The calculated results will becompared with experimental results.

-lOa

a

10

20

30

40

50

X (mm)

Fig. 8. Electric field distribution along the horizontal axis in a bellows at 15.9 GHz.

2) M. Hara, T. Wada, K. Mitomori, and F. Kikuchi:
Proc. 11th Int. Conf. Cyclotron and Their Applications, p. 337 (1987).
3) S. Yokouchi, H. Sakamoto, Y. Morimoto, and S.H.
Be: This Report, p. 279.

276
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-16.

Estimate of the Coupling Impedance for the Storage Ring
T. Yoshiyuki, T. Kusaka, ]. Ohnishi, and S.H. Be

The most important ingredient to evaluate thestability of a particle beam in a storage ring is alongitudinal coupling impedance Z / n and atransverse impedance Z 1. , the latter of which isusually related to the former. The storage ringhas various elements which contribute to theimpedance: a vacuum chamber, bellows, stepchanges, box-like objects, vacuum ports, slits of
RF contacts, and RF cavities. In particular avacuum chamber is designed so as to have aracetrack geometry of 8 cm wide and 4 cm highwith a slot-isolated antechamber in which NEG
pumping strips are installed.
The waveguide modes of this chamber were
estimated by using numerical EM (electromagnetic) field programs, and the impedance of some
vacuum elements was analytically estimated.
(1) Electromagnetic properties of the vacuum
chamber
The TE and TM modes of the vacuum chamber were investigated by using a computer program H2DB.l) The calculation results of the TM
modes for the vacuum chamber geometry withand without an antechamber are shown in Figs. 1
and 2. The H-field lines at a cutoff frequency of
the first TM mode are shown in Fig. l. The EM
fields were confined to the beam chamber and(a) without an antechamber -14.4 GHz(b) with an antechamber - 15.3 GHz

Fig. 2. Calculation of the H-field lines for higher·
order TM mode of the beam chamber region. a,
without an antechamber (14.4 GHz); b, with anantechamber (15.3 GHz).

respective cutoff frequencies for both geometries
were 4.3 GHz. Figure 2 shows the H -field lines
for a TM mode of about 15 GHz. As shown in
Fig. 2 (b), when the beam chamber had an antechamber, deep penetration into the pumping slot
occurred at frequencies above about 15 GHz anda distortion of the H-field lines was remarkable
compared with the beam chamber without anantechamber.
The loss parameter k(fJ'l) is given byk(fJ'l)=L kn(O)exp[ -(W n fJ'jC)2]n(a) without an antechamber - 4.3 GHz~(b) w;lh an aotechamb., - 4.3 GHz

ToAnlecharrt>e,-/Pumping Slot between
Beam Chamber and Antechamber

Fig. 1. Calculation of the H·field lines for the first
TM mode, 4.3 GHz, of the beam chamber region. a,
without an antechamber; b, with an antechamber.

where kn(O) = w nRn / (4Qn) , Rn is the shunt
impedance, Qn the quality factor, Wn the fre quency of n- th mode, and fJ'l rms bunch length.
Above 15 GHz, the slot has significant effects: 1)
when a long bunch is above 1 cm in length, theloss parameter will be little dependent on themodes above 15 GHz; 2) when a short bunch isabout 5 mm in length, the contribution to themodes near 15 GHz will be comparable with thatnear 1 G Hz. The loss parameter for the vacuum
chamber with an antechamber will significantly
differ from that without an antechamber.
(2) Analytical estimation of vacuum chambercomponents
We try to compute each contribution of vari0us parts to the impedance. Before quantitative
estimation of the impedance, we must first get an
idea how much it can be reasonably allowed. The

277

T. Y oshiyuki, et at.

impedance to be allowed is, in a classical stability criterion,2)

I~ I ~:f: (JfY

the average pipe radius of 30.15 mm, and Z 0 =377 n. We obtain Z/n= -i 15.7 n for 576 racetrack type bellows with d = 133 mm, 1= 60 mm
and 192 circle type bellows with d = 74 mm, 1=

where a is the momentum compaction factor, E
the total particle energy, J E / E the FWHM of
relative energy distribution, and I p the peakcurrent defined by
27!R
I p = I AV 3MtJ'l
with I AV the average current in M bunches, withrms bunch length of tJ'l and over a circumferenceof 27!R. n is the ratio of the storage ring circumference of the wavelength of perturbation traveling around the bunch. Using the parameters of
our storage ring; E= 8 GeV, a= 1.3 x 10-\ JE/
E= 3 X 10- 3 , I AV= 100 mA, 27!R= 1,400 m, M=
100 bunches, and tJ'l = 2 cm, we obtain I Z / n I ~0.4 n. This allowance is relatively small compared with other rings. This means that the
impedance problem of our ring is more serious.
Assuming a cylindrical symmetry, we analytically estimated the impedance of different elements: free space, space charge, resistive wall,
bellows, flange, pick-up electrodes, radius discontinuities, slits and holes, and RF cavity. The
method we used to estimate the impedance is theone outlined by A.C. Ruggiero. 3 ) Here we estimate the impedances of bellows, flanges, andstep changes which show the most critical values. We also estimate the impedance of the slits
for RF contacts which screen the bellows. The
RF cavities have a large impedance, but that of
the cavities is not included here.
In our ring, there are about 800 bellows of acircle and a racetrack types. In the low frequency
range, impedance is pure inductanceZ= _ iZ (Ml) In.4
n
27!R
b
0

where M is the number of bellows, I the length
per bellows, d the average radius of bellows, bFlange60 mm in our ring. The bellows must be shielded

because this impedance is much larger than theallowance of the impedance obtained above.
For this purpose we screen the bellows by RFcontacts as shown in Fig. 3. The RF ontact has
many slits around the beam chamber. The
impedance from a slit is caused by the diffractionof electromagnetic wave through it. We estimated the slit impedance for a frequency CaJ =nCaJo from the following equation, where CaJo is therevolution frequency.
2
Z
2-4>a
8 (
+1
n 37!3 R4 b2 n - 1 -; n nc 3" n c

[3 .

2

3) ]

a =.!£lw 2

16

where I :> w for a rectangular slit of dimensions
and b is the pipe radius. Also n c"'" 2 7!R/ I. The
impedance I Z / n I for the RF contacts withslits of 60 mm long and 1 mm wide is shown in
Fig. 4. The maximum impedance is 1.64 X 10- 5 .{}when the frequency is 5 GHz. This shows that the
impedance due only to bellows is steeply diminished by screening the bellows with the RF contacts.
Flanges also contribute to the impedance. We
assume that there are 20 flanges per cell in thestorage ring. The impedance is calculated in thesame fashion as for bellows. In the case of 48
cells, Z / n = i 2.29 n, for 1= 4 mm, d (the outerradius of a gap between flanges) = 174 mm, andb= 32 mm.
In the storage ring, the transition between
different chambers is made with step changes.
We shall take the most pessimistic look and ·consider the step changes in the vacuum chamber
without tapering. Define S as the ratio of the
Impedance of RF Contacts·5x10(n) 2 .0 . , - - - - - - - - - - - - - - - - - , I : 60 mm

w -1 mm

Total IZ/nl
1.5c:;::; 1.0

IZlnl
0.5

0.0 +---~~~~~._r_-:::::;:::..~~~~..-I.1
1
10

Fig. 3. RF contacts by which the bellows arescreened on the vacuum chamber with the antechamber.

Frequency (GHz)

Fig. 4.

Impedance of RF contacts.

278

T. Yoshiyuki , et al.

(0)

0 .4

Impedance of Step Changes..,..--_ _ __ __ _ _ _ _ _ _--, b = 30 .15 mm
d = 20.33 mm

0.3

Total
c
......
N

IZlnl

Imagin ary Z/n
0.2

0.1

Real Z/n

0 .0
10

100

Frequency (GHz)

Fig. 5. Impedance of step changes.

outer dimension to the inner dimension d . We
take S = 1.5. The impedance per the step changeisZ = (1 + i n ) 2Z 0 (S-1) z---.!L
n
n
2nR

4nR
for n < 4d(S - 1)
= (1 + i n) 8.25 X 10- 4 0
If n > n w,

z _z

0
(S - 1)30
n - 2nnn0Since there are 96 steps in the ring, the impedance gets 0.26 0 at maximum as shown in Fig. 5.
This value must become an issue, but in practicethe steps are soften by long tapering sections topreserve matching from one side to another.
The preliminary calculations show that themost critical elements are bellows, flanges, andstep changes. For bellows, the impedance is suffi ciently decreased by screening them with RFcontacts. The step changes are in practice tapered smoothly and the impedance becomes small.
The effect of flanges on impedance must be
studied in more details. Thus we need the way todecrease the impedance of flanges. The next stepis to test these parts in simulation programs. The
impedance measurements are also necessary tocheck the estimation.

References
1) M. Hara, T. Wada, A. Toyama , and F. Kikuchi : Sci.
Papers 1. P. C. R., 75, 143 (1981) .
2) E. Keil and W. Schnell: CERN ISR-TH-RF 69/ 48.
3) A. G. Ruggiero: BNL Informal Report, Aug. (1979) .

279

RIKEN Accel. Prog. Rep. 22 (1988)

V-2-17.

Pumping System for the 8 GeV Storage Ring

S. Y okouchi, H. Sakamoto, Y. Morimoto, and S.H. Be

In order to obtain a beam lifetime of 20 h, thevacuum system of the 8 Ge V storage ring must
maintain a CO partial pressure of 10- 10 Torr allover the ring. A gas load in the vacuum systemdepends on synchrotron radiation (SR)-inducedgas desorption and thermal desorption. SR-induced gas desorption decreases with an integrated photon flux. This is directly related to the integrated electron beam currents. The gas load, Q,
can be expressed by Q=2.49XI0- 4 D - 2/3 Torr l/s
for 0.1 A at 8 GeV, where D is an integrated
electron beam current in Ah unit. The total thermal gas load is 8.5 X 10- 5 Torr l/s. In this estimation, we considered an extruded aluminum alloy
as a chamber material and an oxygen-free copper as a crotch 1) material. For the outgassing
rate of these materials, we assumed 5 X 10- 12
Torr l/s cm 2 • The total inner surface area of thechamber and crotch is 1.7 X 107cm 2. The gas load
is summarized in Table 1.
Figure 1 shows the pumping system per cell of
the ring. The main pumping system is based on a
non-evaporable getter (NEG) strip whose details
are described in this report. 2) The distributed
NEG strips are used in both straight and bending
chambers, but distributed ion pump (DIP) isequipped only in a bending chamber. In a straightchamber, a sputter ion pump (SIP) and a titanium
sublimation pump (TSP) are mounted on anabsorber where many gas molecules areproduced by SR. SIP, TSP, and Lumped NEG
pump are installed at the crotch where a heavy
gas load is expected by SR. SIP and the Lumped
NEG pump are attached to a trapping room topump almost all the SR-induced gas molecules
before they have a chance to bounce around in
Gas load in the ring.

Table 1.

SR-induced
gas load(Torr li s)

Thermal gas
load(Torr lis)

Total gasload
(Torr lis)1
10

2.5X10-4

8.5x10- 5

3.4 X 10- 4
1. 4 X 10- 4100

1.2x10- 5D(Ah)

5.4 X 10-5ii

9.7x10- 5- - Distributed NEG strips~SIP~ Crotchr;(lTSP~- - - DIP

IVlL umpe d NEG pump
LJ

• Absorber~ TMP

t><l All metal valve

Fig. 1.
Table 2.
ring.

Pumping system per cell of the ring.
Effective pumping speed per cell of theunit l/s

Section

NEG
strip

Lumped

DIP

SIP

NEG

Total

pump

Straight 1 , 130
chamber
Bending
300
chamber
AbsorberCrotch

420

Total

420

1,430

TSP

1,130
720
1,940

680
680

2 , 200

2,620
4 ,8203,880 1,360

2,200

9,290

1 ,940the beam chamber. Our main pumping system isbased on the NEG strip but a feature of thepumping system is a mixed pumping one which
consists of a distributed NEG strip, DIP, SIP,
TSP, and a Lumped NEG pump.
The effective pumping speed (CO) per cell islisted in Table 2. The values of SIP and a
Lumped NEG pump in the crotch are those at thetrapping room and the others at the beam chamber. The total pumping speed of the ring is
9,290 X 44 (cell), i.e., 4.1 X 105 l/s. Since the total
gas load in the ring is 9.7 X 10- 5 Torr l/s (seeTable 1), the expected average pressure becomes'"'-'2 X 10- 10 Torr (CO equivalent) at 100 Ah D.
The calculated pressure gradient profile over
one cell is presented in this report. 3)
As the NEG materials, two types (St 101 and St707) are available. They are different in operating temperature. In our ring, St 707 is favored.
The reasons are as follows: (1) Activation temperature is higher for St 101 ('"'-'700°C) than for St
707 ('"'-'450°C). (2) The number of thermal cycles

280

S. Y okouchi, et al.

Base plate
SupportCeramics insulator
NEG strip(St 707)

Slot
Beam chamber

Antechamber

Fig. 2. Cross section of the vaccum chamber with
NEG strips.

(i.e. lifetime) for heat treatment is limited in caseof St 101 compared with St 707. (3) More electrical power for heating is required for St 101 thanfor St 707. (4) Thermal affection to the chamber
is more serious for St 101. (5) Because of alarger thermal expansion of NEG strips, aninstallation of the strips in the narrow space (asshown in Fig. 2) is difficult.
The sorption capacity of NEG is sufficient forH2 since its sorption is reversible. The interval ofregeneration cycle is expected to be about 2.5 y
at a ring operation pressure of 1 x 10- 9 Torr.
Although CO is permanently sorbed in the getter
material, the lifetime for CO is estimated atabout 20 y. For this duration the reactivation
cycle will be required about 20 times.
Figure 2 shows an assembly of NEG strips inthe chamber. The support holds both sides of the
NEG strip, where getter materials are not deposited. The employment of this supporting
method is to prevent the getter materials fromexfoliation during the heating; the exfoliation of
the getter materials originates in temperature
ununiformity. Each support insulated withceramics insulator is discretely fixed on the
baseplate.
A turbo-molecular pump (TMP) is to be used
for backup pumping. TMP is a ultra-high vacuum pump which can dynamically pump a large
quantity of gases. Therefore, the TMP will be
run in the range of low pressure before eachpump of the main pumping system starts up.
All aluminum alloy gate valves with an RF
contact are mounted for isolating the chambers
at each end of the cell. By closing them, each cell
can independently be pumped after venting toatmospheric pressure and subjected to leakcheck.
Bellows with an RF contact are used forcompensating misalignments during installationof the chambers, valves, and other components,

(a)

(b)

Fig. 3. Isometric drawing of all aluminum alloygate valve with an RF contact (a) at open positionand (b) at closed position.
FlangeFig. 4. Isometric drawing of bellows with an RF
contact.

and thermal expansion during ring operation andbakeout.
The aluminum alloy gate valve and bellows
were specially designed to minimize RF impedance. These are shown in Figs. 3 and 4. Further
development of a valve and bellows with asmoother, simpler, and more conductive wall isstrongly required.
Aluminum gaskets are used for connection of
the flanges.
References
1) Y. Morimoto, S. Yokouchi, H. Sakamoto, and S.H.

Be: RIKEN Aeeel. Prog. Rep., 21, 247 (1987).
2) S. Y okouchi, H. Sakamoto, Y. Morimoto, and S.H.
Be: This Report, p. 283.
3) H. Sakamoto, S. Yokouchi, Y. Morimoto, S.H. Be,
and I. Aoki: This Report, p. 288.

281
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-18.

Stress Analysis of the Vacuum Chamber for the
8 GeV Storage Ring
T. Nishidono, * H. Kakui, * S.H. Be, H. Sakamoto,
S. Yokouchi, Y. Morimoto, and Y. Oikawa

The vacuum chamber consists of two chambers with different shapes. We used aluminumalloy chambers (A6063- T6) to mInImIZe
synchrotron radiation (SR) -induced desorption
as well as thermal outgassing.
The cross-sectional view of the vacuum chambers for the straight sections is shown in Fig. l.
This vacuum chamber consists of an beamchamber and a slot-isolated antechamber inwhich non-evaporable getter (NEG) strips are

installed.
The cross-sectional view of the vacuum chambers for the bending magnet is shown in Fig. 2.
This vaccum chamber consists of beam chamber, a slot-isolated antechamber, and a pumpchamber. We install a distribution ion pump(DIP) and a NEG strip pump on opposite sides ofthe beam chamber.
These chambers contain cooling channels forremoving the thermal load of SR light.

Slit

Cooling channel------Slol--------

Ceramic insulator

o.

246

8

. em

10

Scale

Fig. 1. Cross-sectional view of the vacuum chamber for the straight sections.
Sheath heater

Cooliog channel

Antechamber

o,

2

4

6

8,

Ceramic insulator

10
em
,

Scale

Fig. 2. Cross-sectional view of the bending magnet vacuum chamber.

• Ishikawajima-Harima Heavy Industry Co., Ltd.

282

T. Nishidono, et at.

,/I'>".(~oN~ . \\~y"'I//:r//.
11

tE:

~~

- -.~

8

131

40

en

N

I
77 m~ 7\1") 1

20

:::

20

83

313

The vacuum chamber for the straight sections.

69

<1.

20

40

50

83

20

29 0

The vacuum chamber for the bending magnet.
Fig. 3. Analytical model.

The vacuum chamber for straight sections. Displacement (mm)- MAG
MIN: O.OOE+OO MAX: 4.50E- Ol. Stress (kg/ mm 2 )-(D: 2 .1, @: - 2 .6,@ : - 2.4, @ : -1.9.

The vacuum chamber for bending magnet. Displacement (mm)- MAG
MIN: O.OOE+OO MAX: l.03E-Ol. Stress (kg/ mm 2 ) - (D: 1.7, @: -2. 4,@: -1.5, @: -1.3.
Fig. 4. Calculation results of stress analysis.

Flexible sheathed heaters are inserted into
baking channels. Further, these chambers arethermally insulated with Kapton films.
The chambers must be designed so as to standthe pressure difference between the atmosphericpressure and the vacuum.
The stress of the vacuum chambers was calculated, on the base of the analytical model shownin Fig. 3. Calculated results are shown in Fig. 4,
which shows that 1) in the vacuum chamber forstraight sections, the maximum displacement(J Y) is 0.45 mm at the slot, and the maximum
stress (<1) is 2.6 kg/ mm, and 2) in the vacuum
chamber for the bending magnet, the Lf Y is 0.10mm at the slot, and the <1 is 2.4 kg/ mm. The
value of the stress of these vacuum chambers areless than the allowable stress of 6.8 kg/ mm formaterials to be used as a chamber. Thus, thesevacuum chambers will withstand the pressure
difference between the atmosphere and the vaccum. However the displacements are larger thanthe mounting accuracy required for beam position monitors. In our storage ring, monitors must
be mounted with a high accuracy of O. 1 mm on
the vacuum chambers.
This means that a proper countermeasure for
reducing displacements must be taken.
These problems will be discussed, and results
will be checked with prototype model chambers
which are now under fabrication. Calculations ofa thermal stress are in progress.

283
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-19.

Pumping Characteristics of NEG Strip

S. Yokouchi, H. Sakamoto, Y. Morimoto, and S.H. Be

We experimentally investigated the pumping
speed of a non-evaporable getter (NEG) strip(trade name St 707), which is planned to be used
as a main pump in the pumping system for the 8
GeV storage ring (details of the pumping system
are described in this report l )).
NEG Material
The NEG material available for a strip is a
84 %Zr-16%AI alloy (St 101 supplied by SAESGETTERS S. p. A) or a 70%Zr-24.6%V-5.4%Fe
alloy (St 707). These alloys are deposited on a
support strip of constantan in powder form. The
getter alloy is suitable for pumping active gases,
but not for methane and noble gases. The alloy
reacts with active gases such as CO, CO 2, O2,
and N2 to form stable chemical compounds.
Hydrogen and its isotopes, however, form a solid
solution in the alloy and can thus be reversibly
sorbed. NEG develops its pumping characteristics after heat treatment called "activation".
The heat treatment diffuses a thin surface layer,
which is formed by exposing to air during the
manufacturing steps, into the bulk and makes thesurface of the getter clean and enable to sorb.

Another heat treatment called "reactivation" isneeded to recover the plJ.mping speed of NEG
which has fallen to low values by sorbing active
gases. The optimum treatment for full activation
recommended by the manufacturer is heating for"'-'45 min under vacuum at "'-'700°C for St 101 andat "'-'450°C for St 707. Hydrogen sorbed in NEG
can be released from the getter by the regeneration treatment, which is necessary when thepumping speed for H2 is fallen bellow an acceptable limit or H2 quantity sorbed is approachingan embrittlement limit of 20 Torr l l g. The timenecessary for the regeneration of NEG is
obtained from t · =M X (1 1qf -II qj) X 10-(A - B I T) I F
s, where M is the weight of a getter material ing, qf the final H2 concentration in Torr l l g, q! theinitial H2 concentration in Torr l l g, A and B theconstants, T the regeneration temperature in
kelvin, and F the pumping speed of a backing
pump in li s. The regeneration process, however,should not be performed times without number
because of the development of thermal fatigue
effects in the getter-coated strips. The thermal
fatigue, which depends mainly on the tempera-

T5P

BAG2

I

QMA

V4

BAG3
V2

Ef ~ l~iCHAMBER3CHAMBER 2

I,--+-----.--i~ V1
V5 ~ VV1

8Jxl~

TMP2 (50 Vs)

V3

S

[J

I=Z<

g

~~
r:f\
W
-

NEG

~

--=

cD

TMP1 (360 Vs)

PG

l

I-I
I-I

To fore pump

SIP{250 Vs)

NEG: Non-evaporable getter (5t 707) strip

BAG1,2,3 : Bayard-Alpert nude gauge

SIP: Sputter Ion pump

PEG: Penning gauge

TSP : TitanIum sublimation pump

PG : Pirani gauge

TMP : Turbo molecular pumpV1,2,3.4,5 : Manual gate valve

QMA : Quadrupole mass analyzer

VLV: Variable leak valve
VV1,2 : Venting valve

Fig. 1.

Schematic diagram of the device with test instruments.

To fore pump

284

S. Y okouchi, et al.

ture and the duration of regeneration, causes
peeling-off of the getter powder.
Measurement
Figure 1 shows a schematic diagram of the test
device. The chambers are made of extruded
aluminum alloy (A6063-T6). Chambers 1 and 2
form a test dome for measuring the pumping
speed. In chamber 3, NEG strips were installed
as shown in Fig. 2, and a sputter ion pump and atitanium sublimation pump, which would be usedin the 8 GeV storage ring, were set up to investigate a vacuum performance of the mixed pumping system. A turbo-molecular pump (TMP2)
were installed in chamber 1 to prevent the partialpressure buildup of gases such as CH 4 and Ar
which cannot be pumped with NEG. The effective surface area of the NEG strips is 506 cm 2 andthe total weight of the getter material is 21.5 g.
Pumping speeds of the NEG strip were measured for H2 at room temperature and 275°C, andfor CO at room temperature by following procedures. For H 2, the initial H2 quantity sorbed (H 2concentration) is given by log P=4.8+2Iogq6,1661 T ,2) where P is the equilibrium pressure of
H2 in Torr after appropriate regeneration, q theH2 concentration in Torr I l g, and T the regeneration temperature in kelvin. The pumping speeds
were measured by two methods: (1) Gases are
introduced at a constant throughput, and thepumping speeds were measured periodically, and(2) gases were introduced at various throughputs,
and the pumping speeds were measured.
For CO, the initial CO quantity sorbed is regarded as zero after activation at ~450°C for ~ 10min. The pumping speed was also measured by
the same method as (1) for H 2. The quantity ofsorbed gas is calculated by adding the integrated
throughput to the initial gas quantity sorbed.
The pumping speed is given by S = C X (PI - P2)1P2
I Is, where C is the conductance of an orifice inli s, PI the pressure at BAG 1 in Torr, P2 that at
BAG 2 in Torr.
The pumping speeds of the NEG strip (St 707)
for H2 are plotted in Fig. 3, in which curve 1(obtained by the measuring method (1» shows

~

g'j

<D ~

N
E

r-a

~,,~ \.
~

o

o
G)

~

~, 1'\>--

"C
G)
G)

~

a.

C/J

RT Throughput : 8X10 -5 Torr.Vsec.... RT(l)..... RT(2)
-G-

CI

c:;

a.
E
::s

....

Cl.

DTt'>'... RT(4)... 27Sb(1)... 27Sb(2)RT: Room te,mperature

.1
.0001

.001

.01

.1

Sorbed Quantity (Torr.llcm2)

Fig. 3. Pumping speeds of the NEG strip (St 707)
for H2 at room temperature and 275°C.

N'
E
0
0G)

",

~
~

: 5xlO -5 Torr.Vsec

E\"

,\,

a.
t/)

.~

ClI
c:;

E

Throughput

""-

"C

a.

-&

10

10

::s

Cl.

......
"'IIIno..

.-u.IIIJIIIl1(f1 (f 510 4

1 If a10 2

Sorbed Quantity (Torr.llcm2)

Fig. 2.

Assembly of NEG strips in the chamber.

Fig. 4. Pumping speeds of the NEG strip (St 707)
for CO at room temperature.

285

S. Y okouchi, et al.

that the pumping speed for H2 does not decrease
rapidly. This means that the H2 gas adsorbed on
the surface diffuses into the bulk of the getter,and the pumping speed decreases graduallyowing to the reduction in the bulk diffusion withan increase in H2 concentration. Other curves
were obtained by the measuring method (2).
Fluctuation in the data is due to the change in thethroughput during the measurement. It has beenreported 3 ) that the pumping speed for H2 depends
on the throughput. The pumping speed at 275°C is
higher than that at room temperature, because
the bulk diffusion is promoted at high tempera1.0...------------,
Total pressure: 2.1X10-8Torr

0.8

(a)

~
~

16

2

0.2,-------------,

0.6

28

~

1

ture.
Figure 4 shows the pumping speed for CO. The
pumping speed decreases rapidly owing to anincrease in the quantity of CO sorbed because oflittle diffusion at room temperature. A slope,"-' -1, of the curve is in agreement with theresults of Benvenuti, et al. 3 ) A drastic change at
the sorbed quantity of "-' 1 x 10- 3 Torr l / cm 2 was
ascribed to an error due to a change in themeasuring range of the gauge (BAG 2).
The results of residual gas analysis are shownin Figs. 5 and 6. In Fig. 5, where only a NEG
strip was used, significant peaks of CH 4 (M / e=16) and Ar (M / e=40) appeared, these results
indicate that the NEG strip has no pumping
capacity for CH 4 and Ar.
Total pressure: 5.3X1Q-9Torr

2

0.4

(a)

16

28
Mle

1 8 - 4,0
2I"..LU..-IL.JI,L----L.U._ _--'-_----I

0.0 LL-_1_.L1

1.0,-------------.
Total pressure: 1.5X10-8 Torr
0.8

~
(b)

~

2

Mle

28

0.6

0.2,------------,~

j

Total pressure: 2.0X1Q-9Torr

2

0.4

16

0.2

12

4t

.111

(b)

0.0 '-'-----Ll.JLLI..&.._ _L - _ - - - - L . . _ - - . J
Mle

16

28

,,1,18 I

0.3r------------,
Total pressure: 1.5X10-9Torr

4~

0.0 '-'-_ _....a.LI-L-_.l..-_--L_-.I
Mle

~

& 0.2

2
28

(c)
-_Ie

0.1

Fig. 6. Mass spectra of the residual gases, (a) witha combination of NEG strip (at 275°C) and TMP2,(b) with a combination of NEG strip (at 275°C),
TMP1, and TMP2.

12. 1,6,18

0.0 L L - - - - L - - L - L - _ . . L -_ _ _ _-1

MI.

Fig. 5. Mass spectra of the residual gases, (a) with
only NEG strip (at room temperature), (b) with a
combination of NEG strip (at room temperature)
and TMP2, and (c) with NEG strip (at room
temperature), TMP1, and TMP2.

References
1) S. Yokouchi, H. Sakamoto, Y. Morimoto, and S.H.
Be: This Report, p. 279.
2) SAES GETTERS: St 707 (Catalogue).
3) C. Benvenuti and F. Francia:]. Vac. Sci. Technol. A,
6, 2529 (1988).

286
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-20.

Synchrotron Radiation Power Distribution at the
8 GeV Storage Ring

Y. Morimoto, H. Sakamoto, S. Yokouchi, and S.H. Be

Synchrotron radiation (SR) power distribution
along the 6 Ge V storage ring was described. 1)
Later, a beam energy was increased from 6 GeV,
to 8 Ge V, and many other design parameters
were changed with an increase in the beamenergy. SR power destributions along the 8 Ge V
storage ring are calculated under the new design
conditions. At present, the cell number of a lattice is not fixed; however, we chose a 44-celllattice to estimate a thermal load, and SR-o5Fig. 1.

10m

induced outgassing loads for the vacuum chambers and their components.
The layout of various components of the 8 Ge V
storage ring is shown in Fig. 1. SR power distributions are calculated at the positions of a crotch(CR) and an absorber (AB), and from the geometry of a vacuum chamber. The crotch and absorber are placed so as to intercept most of the SR
beam emitted from a bending magnet (BM), andthereby protect the vacuum chamber from SR

Q1 - Q8 : Quadrupole magnet
S 1 - S6 : Sextupole magnet

Schematic layout of a cell of the 8 Ge V storage ring.

radiation. Particularly, the crotch has a highly
concentrated pumping speed to evacuate SRinduced outgas. The crotch is positioned justdownstream of the bending magnet and selectively separate an SR beam which should be transported to the experimental facility. The absorberis positioned just upstream of the bending magnet and the insertion device (ID), and absorbs the
SR beam except that entering the electron beam
passageway. A power density on the crotch isextremely high, but that on the absorber is relatively low. The structure of the crotch is more
complicated than that of the absorber because of
the heigher power and power density of thecrotch. Details of the crotch along with the thermal analysis and geometry of the vacuum chamber are presented in this progress reports. 2 )Four kicker magnets (KM) to be used to inject
an electron beam from the synchrotron into thestorage ring are installed in a section of thestorage ring; one is between BMI and CRl, one
between ABI and BM2, and two in the straightsection where ID is normally installed. Therefore, CRI and ABI are located at a distance ofapporximately 1 m from the end of BMI and

N 100
0
==

~

~

>t-

10

ooZ
w

0

a:

w

::0

II

0..

X
<C

==

.1
8
•

§:
~

a:

BMl RADIZI BM2RAD
6

w

::0
0..

4

0

W

m

a:

0
m

(J)

2

<C

a

,

0
0

5

10

15

n

I

I

I

20

25

30

LENGTH(M)
IBM111t

CR1

IIBM211

t

AB1

f

CR2

t

t

I

II

AB2

AB3

AB4

I 110 It

Fig. 2. Absorbed power and maximum power
density distributions.

Y. Morimoto, et al.

BM2, respectively. Thus we take a space for
installation of the kicker magnets. Furthermore,
AB3 is added just downstream of the ID forprotecting the valve positoned at the back of theID.
The SR power, Pr in kW, is given by Pr=
26.6E3BI, where E is the electron energy in GeV,
Table 1.
Area

Absorbed powers and power densities.

a) BM1 Radiation
CR1
AB1
CR2
Total
b) BM2 Radiation
CR2
AB2
AB3
AB4
CR1
Total

Absorbed
power
(kW)

Max. power
density(kW / cm2)

63.0
29.1
7.9

5.9
2.7
0.7

2l.3
l.8
0.7

100.0

9.3

52.9
37.3
4.6
l.6
3 .6

4.9
3.5
0.4
0 .2
0.3

100.0

9.3

% Absorbed

25.3
2.7
0.8
0.4
0.2

287

B the magnetic field in T, and I the electron
current in A. In the design parameters of E = 8
Ge V, B =0.6 T, and 1= O.lA, the total SR powerfrom 88 BM in our storage ring corresponds toabout 820 kW. Thus the SR power emitted fromeach BM becomes approximately 9.3 kW.
The calculated SR power distributions including power densities along the 8 GeV storage ringare shown in Fig. 2; Table 1 lists the numericalvalues. The maximum power density on thecrotch is 25.3 k W / cm 2 and the total SR power
emi tted from each bending magnet is 9.3 k W. In
our 8 GeV storage ring, no SR beam strikes thewall of vacuum chambers.
The crotch which can withstand the highpower density of 25.3 k W / cm 2 is under construction. The design of the absorber has not been
started yet, but a trapping structure similar tothat of the crotch will be considered for ABI and
AB2, because of their high absorbed powers.
References
1) Y. Morimoto, H. Sakamoto, S. Yokouchi, and S.H.
Be: RIKEN Aeeel. Prog. Rep., 21, 245 (1987).
2) Y. Morimoto, S. Yokouchi, H. Sakamoto, S.H. Be,
and T. Shirakura: This Report, p. 292.

288
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-21.

Pressure Gradient Profile in the 8 GeV Storage Ring

H. Sakamoto, S. Yokouchi, Y. Morimoto, S.H. Be, and 1. Aoki*

The method of calculating pressure distribution in our storage ring and results are described
below. This calculation is strongly required indesigning the pumping system for the storagering.
1) Analytical model of pressure distribution
On the basis of the analytical model shown in
Fig. 1, a fundamental expression!) for the pressure distribution is given by2
d P + qu - SuP -_ 0
(1)
CUdX2
where Cu is the conductance against unit length,
qu the outgassing rate per unit length, and Su the
distributed pumping speed per unit length.
L

I

q3

p~
Q,

Fig. 1.

I

q1--1

x

I

~ t-q2 ~2

I I

q4dX

I

Q2

Analytical model of pressure distribution.

Here we made following assumptions:[1] The cross-sectional shape of the chamber isconstant;[2J The thermal outgassing rate is constant; and[3J The distributed pumping speed is constant.
By solving Eq. 1, the relation between the pressure P and the flow rate Q is given by) = (All AI2) (PI ) + (A1 3 )( P2
Q2
Al4 AI5
QI
Al 6

where PI and P2 are the pressueres at theentrance and the exit of each element, respectively, QI and Q2, the flow rate at the entrance andexit of each element, respectively, All, A 12 , A 13,
A 14 , A 15 , and A I6 , the constants determined by
the elements.
2) Calculation method
Since the vacuum chamber is devided intoelements owing to the difference in the distributed pumping speed and the outgassing rate perunit length, the relation between the pressure andthe flow rate is given by• Osaka Vacuum, Ltd.

where i = 1 - n.
In a closed vacuum system like a storage ring,PI = Pn+ I and QI = Qn+l . Then we obtain 2n simple equations as follows
All x PI+A l2 x Ql - l x P2+Ox Q2 = - AI3+Al5X QI +ox P2-1 x Q2= - AI6-1 x PI +0x QI + Ani x Pn+An2X Qn= - A m
ox PI- l X QI +An4XPn+Ans X Qn= - An6

Al4 x PI

The above equations can be rewritten to amatrix of (2n+ 1), (2n) -type as given by
All AI2 -1 0 ·AI4 AI5 0 -1 •• A 21 A 22 - 1 0• A24 A 25 0 - 1

-1

0···
o -1 · · ·

- AI3
- AI6
- A 23- A 26
AnI An2 - Am
An4 An5 - An6

The pressure at each element and the flow rate
are obtained by solving this matrix.
If a front end for photon beam lines is set along
a line tangential to the electron orbit in thestorage ring, the matrix is further rewritten to
the following matrix of (2n+3), (2n+2)-type,
All Al2 - 1 0 ·Al4 Al5 0 -1 .
• A2l Al2 -1 0
• A24 A25 0 -1

-A 13
-A 16
-A 23
-A 26

Anl Am - 1 0 - An3
An4 Ans 0 - 1 - An6- 1 0 -Po
0 - 1 - Qo

Table 1.

Parameters for the 8 Ge V SOR.

Beam energy
Beam current
Dipole field
Circumference
No. of cell

8 GeV
100 rnA
0.6 T
1,500 m44

289

H. Sakamoto, et al .

~

.f!\

~

R.

~.

I

I\

f~ ~

w

a:

[,.,.

::J
U'J
U'J

w
a..

a:
d"1
rflr

iii"

.-tmAJI"
WI

to · 100 . 00!IiIiI.

to . OO""\'K'----"'1

Total after 1Ah
Total after lOAh
Total after l00Ah

10.0

DISTANCE [m)DISTANCE [m]Fig. 2.

20.0

20.00

Pressure gradient profile.

when Po and Qo are the initial conditions, i.e., thepressure and the flow rate at a connection point
between the storage ring and the front end.
3) Results
A pressure gradient profile is calculated basedon the pumping system 2 ) and the synchrotron
radiation (SR) power distribution. 3 ) The main
parameters for the 8 Ge V storage ring are shownin Table 1. The SR induced outgassing rate (QSR)
is given by QSR =2n°rJK, where n° is the numberof photons per second (= 1 X 10 18 E [Ge V] I
[rnA]), rJ is the number of molecules per photon(= 5.0 X 10- 6 D - 2I3 [Ah], D the integrated stored
current), and K = 3 .11 X 10- 20 [Torr l/moleculel
In this calculation, we assumed that the distribution of the SR induced outgassing rate is in
proportion to the rate of SR power deposited at
crotches and absorbers, and that the compositions of residual gases are 80% H2 + 20% CO.
Calculated pressure gradient profiles over one
cell are shown in Fig. 2. Three curves showrespective pressure profiles after the integrated
stored current of 1, 10, and 100Ah. From Fig. 2
we can see that an average pressure over the ringdecreases with an increase in the integrated
stored current. The area where absorbers Ab(l)and Ab(2) are placed shows the heighest pressurein the ring. This means that pumping capabilities
at the absorbers are not enough. After 100 Ah,

Fig. 3.

Partial gradient profile.

however, the average pressure is about 0.2
nTorr and a beam lifetime of about 20 h is
expected to be achieved easily. Further, Fig. 2
shows that the pressures at the bending magnet
and straight sections, except the area where thecrotches and absorbers are placed, are notaffected appreciably by the integrated stored
current. Thus, we conclude that the pressures atthe bending magnet sections and the straightsections are mainly governed only by the thermal
outgassing rate. For a mixture of 80% H2 and
20% CO, partial gradient profiles for H2 and CO
gases are also calculated and the results areshown in Fig. 3. In this calculation we considered the pumping speed and conductance forrespective gases. From Fig. 3 we can find that thebeam lifetime must be estimated for CO gas
because the lifetime is in inverse proportion to
the square atomic number of the gas atoms. The
lifetime of greater than 20 h can be ensured evenwith the partial pressure of CO calculated above.
References
1) T. Ikeguchi, M. Matumoto, S. Veda: KEK Rep., 87-8

Aug. (1987).
2) S. Yokouchi, H. Sakamoto, Y. Morimoto, and S.H.
Be: This Report, p. 279.
3) Y. Morimoto, H. Sakamoto, S. Y okouchi, and S.H.
Be: This Report, p. 286.

290
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-22.

Outgassing Rate of an Extruded Aluminum Alloy Chamber
H. Sakamoto, S. Yokouchi, Y. Morimoto, and S.H. Be

The outgassing rate of various vacuum materials is important factor in the design of a vacuum system. In a storage ring, particular, thematerials of low outgassing rates are required.
Thus we are considering to use an extruded
aluminum alloy (A6063T6) for the material of
vacuum chambers. The chemical composition of
A6063T6 is 0.55 w/ o of Mg, 0.44 w/ o of Si, andthe rest is AI. This aluminum alloy is extruded in
the atmosphere of Ar + O2 and no surface treatment for using in the vacuum is necessary. To
measure the outgassing rate of the extruded
alumunum alloy, we constructed an experimental
device as shown in Fig. 1. This device consists ofthree chambers made of extruded aluminumalloy. The outgassing rate is obtained by estimating the gas quantities from the inner surface ofthe chamber 1. The specific method will be described ' later. On the respective outsides of thechambers, sheathed heaters are welded for bak-Fig. 1. Outline of the device.

ing the chambers, and chromel-almel thermocouples are also attached for measuring the baking
temperature.
A schematic diagram of the device with test
instruments is shown in Fig. 2. A Bayard-Alpert(BA) nude gauge (BAGl) in the chamber 1, a BA
nude gauge (BAG2), and a quadrupole mass

TSP

BAG2

QMA

V4

Jxl
I ><

~Q~~
J

I~~____~I~I_~_--~_~~~I

BAG3

D~

CHAMBER3CHAMBER 2

To fore pump

V5~
TMP2 (50 Vs)

Vl

~

V31

><

D

18r

PG

1

I-I
I-I

To fore pump

SIP (250 Vs)

NEG: Non-evaporable getter (St 707) strip

SIP: Sputter ion pump

BAG1,2,3 : Bayard-Alpert nude gauge
PEG: Penning gauge

TSP : Titanium sublimation pump

PG : Plranl gauge

TMP : Turbo molecular pumpV1,2,3,4,5 : Manual gate valve

QMA : Quadrupole mass analyzer

VV1,2 : Venting valve

Fig. 2.

Schematic diagram of the device with instruments.

291

H. Sakamoto, et at.

analyzer (QMA) in the chamber 2 are installed. A
sputter ion pump (SIP), a titanium sublimation
pump (TSP), non-evaporable getter (NEG) strips,
and a turbo moleculer pump (TMP) are mounted
on the chamber 3 with gate valves (V2,V3,V 4).
Thus, it is possible to combine these pumps by
opening or closing the gate valves.
The outgassing rate (Q) of the chamber 1 was
obtained from Q = C (P1- P2)IS, where PI is
the pressure of the chamber 1, P2 that of thechamber 2, and C is the conductance (2.28l Is) of
the orifice of 5 mm in diameter. This orifice isplaced between the chamber 1 and 2.
Measured outgassing rates for the chamber 1
as a function of the pumpdown time are shown in
Fig. 3. At first, the chambers were evacuated forabout 190 h with 300 li s TMP and then 250 lis
SIP instead of TMP. The increase in the outgassing rate after 20 h is due to the prebaking effectof the chamber for 50 h at 80°C. This prebaking
was carried out to check the leak between
flanges. After prebaking, the minimum outgassing rate was 8.0 x 10- 12 Torr li s cm 2 • Figure 3
shows that the outgassing rate keeps constantduring approximately 700 h after prebaking.
This means that the baking at 80°C is not enoughto decrease the outgassing rate of the chamber.
After checking leak, the chambers was baked for

flash

pumpdown time [hour]Fig. 3. Outgassing rate of the extruded aluminum alloy chamber.

40 h at 150°C. After the baking, the outgassing
rate decreased from 8.0 X 10- 12 Torr lis cm 2 after
prebaking to 9.0 X 10- 13 Torr lis cm 2 at about 150

h after the baking. This outgassing rate is inapproximate agreement with the results reported
so far. Evacuating with only SIP, the minimumpressure of the chambers 1 and 2 were l.6 x 10- 9
Torr and 8.8 X 10- 10 Torr, respectively. Furthrmore, by evacuating with TSP in adittion to SIP,
the pressure of the chambers 1 and 2 ultimately
decreased to l.2 x 10- 9 Torr and 4.2 x 10- 10 Torr,
respectively, with no variation in the outgassing
rate.

292
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-23.

Thermal Analysis of the Crotch at the 8 GeV Storage Ring

Y. Morimoto, S. Yokouchi, H. Sakamoto, S.H. Be, and T. Shirakura *The design of a crotch which can absorb highpower density ('"'-'25kW Icm 2 ) is one of the mostdifficult and urgent problems in the vacuum
system of the 8 GeV storage ring. We designed a
new type crotch. The essential feature of ourcrotch is its structure, in which particles such as
photo-electrons, reflected photons, and SRinduced outgasses from the crotch are efficiently
trapped. Furthermore, three different pumps (seeFig. 1) provided in the crotch evaculate gas
molecules before they have a chance to bounce
into an electron beam chamber.
An isometric view of the crotch is shown in
Fig. 1. The main body, which is made of oxygenfree copper (OFHC), consists of two rooms: one isfor an electron beam passageway, which was
fabricated to match a cross section of an electron
beam chamber, thereby minimizing heigher ordermode losses. The other is for trapping particles
as described above. The trapping room is isolated from the electron beam channel except theregion of a slit with low conductance. An SR
beam from a bending magnet enters the trapping
room through the slit and strikes absorber 1(ABl) and absorber 2 (AB2), which are also madeof OFHC and inserted into the main body. Not
only AB1 and AB2 on which SR beam strikes
directly but also the main body is made of OFHC,
because (1) SR-induced desorption is caused byphoto-electrons which bounce in the spacearound AB1 and AB2 at random, (2) photoelectrons are produced by reflected photons
besides the photons which strike AB1 and AB2
directly, and (3) OFHC has low photo-electron
yield under SR irradiation and a low outgassing
rate compared with other materials. Cooling isachieved by flowing water through a coolingchannel in AB1 and AB2.
The SR power from the bending magnet isconcentrated wihtin a small vertical angle ('"'-'11y), thus resulting in large power densities at thesurface irradiated with SR beams; here y is theratio of the electron beam energy to the electron
rest-mass energy. For 8 GeV, 100 mA, and B =0.6T, the power and its density at the crotch are* Kobe Steel, Ltd.

Port for TMP

Trapping room

Port for BA guage
E.beam channel

Fig. 1. Isometric view of the crotch.
Table 1. Absorbed powers and power densities at thecrotch.
Absorbed power(kW)

Max. power density(kW/ cm2)a) Crotch 1
Absorber 1
Absorber 2

1.08
5.09

21.3

Total

6.17

b) Crotch 2
Absorber 1
Absorber 2

1.17
4.48

Total

5.65

Area

13.8

25.3
15.5

given in Table 1. The difference in thermal loads
between crotch 1 (CR1) and crotch 2 (CR2) is dueto the difference in these positions. CR1 and CR2
are located at a distance of approximately 1 m
and 0.5 m from each end of the bending magnet,
respectively. We chose a thermal load at CR2 as
the boundary conditions for thermal analysis
because it is higher than that at CR1. Two model
regions as shown in Fig. 2 are considered forAB1 and AB2. We performed thermal analysis inthree dimensions for AB1 and in two dimensions
for AB2 because of the inherent symmetry of thethermal problem. Furthermore, the geometry of
the model regions is simplified on a conservativeside. Heat inputs are distributed over a strip of

293

Y. Morimoto, et al.

4110 (Cooling channel)

I

Y7

~

~

;.>(

tI

)<.:::z:

j,

(')

N

A!-

~
d

~

c::::> 1

SR t
beam Heated st rl P \...,4110 (Cooling channel)
unit :mm

Fig. 2. Simplified heat transfer model to calculate temperature distributions.

0.13 mm in height for ABI and 0.17 mm for AB2.
Here we assume that the heat inputs are deposited just on the surface. The power densities perpendicular to the SR direction are 25.3 k W / cm 2
(peak power density: 52k W / cm 2) for ABI and15.5 kW /cm 2 (pesk power density: 32 kW / cm 2 )for AB2. In calculation, we assumed that heattransfer occurs only at the surfaces along which
cooling-water flows, and other surfaces are insulated.

The heat flux per unit area, Q, at the watercooled surface is given by(1)
Q = h(Tw - Tc)+ A o3fp 2h 2 (A]24IP]2/ Po M2 f5LPv)(Tw - YsP
Tw>Ts

where h is the heat transfer coefficient, Tw the

50°C

100°C
150°C
200°C

Fig. 3. Temperature distributions computed for absorber 1.

wall temperature, Tc the water temperature, Ao
the coefficient decided by the boundray layer
condition, h the pressure coefficient, A thedegree of bubble, Po and M the constant, f5 thesurface tension, L the latent heat, Pv the vapor
density, PI the liquid density, AI the liquid thermal
conductivity, 4 1the liquid specific heat at constant pressure, and Ys the boiling point. Equation
1 for forced convection heat transfer and Eq. 2 isfor fully developed nucleate boiling. The second
term in Eq. 2 is given by Nishikawa andYamagata. 1) The water temperature and pressure are set to be 30°C and 4 kg/cm 2 absolute(boiling point is 143°C), respectively. To simulate
the heat flow within the model regions, a finite

(2)

100·C

150°C
200·C

Fig. 4. Temperature distributions computed for absorber 2.

294

Y. Morimoto, et al.

element program MARK-IBM was used, which iscapable of solving the Poisson or Laplace equation in three dimensions.
Figures 3 and 4 shows the calculation results
for the two model regions. The calculated maximum temperatures on the surface irradiated withan SR beam are 39TC for ABI and 356°C forAB2. The maximum temperatures on the coolingwall are 15TC for ABI and 11 TC for AB2. These
results indicate that our crotch withstands thehigh power density of 25.3 kW / cm 2. As seen from
Fig. 3, the maximum temperature on the coolingwall for ABI shows that nucleate boiling occurs
on a part of the cooling wall. The maximum
temperature of 15TC on the cooling wall is lessthan the wall temperature of 16TC corresponding to "burn out."2,3) This means that the heat fluxin the area, where uncleate boiling is observed,
does not exceed a critical value above which"burn out" occurs. If the heat flux exceeds thecritical value, the wall temperature increase
rapidly because of the reduction in heat transfer.
It is caused by film boiling and at worst the wall
may be melted down. This is called "burn out."
To avoid "burn out," we must pay much attention not to give excessive heat flux through thewall-water interface.
A prototype model of the crotch is under construction, which is scheduled to be completed by
the end of March 1989. Using an electron beam asa source of thermal loads, we plan experiments
to confirm our design.
References
1) K. Nishikawa and K. Yamagata: Int. ]. Heat Mass

Transfer, 1, 219 (1960).
2) N. Zuber, M. Tribus and J.W. Westwater: Int.
Develop. Heat Transfer, ASME, 230 (1961).
3) S.S. Kutateladze: Zh. Tekh. Fiz., 20, 1389 (1950).

295
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-24. Design of the Low-Frequency Cavity for the Synchrotron
T. Y oshiyuki, T. Kusaka, and M. Hara

A two-RF system is investigated for thesynchrotron of the STA (Science and Technology Agency) SR facility. Acceleration in thesynchrotron is performed at two different frequencies. The low-frequency system (20-50 MHz)is used to capture long macro-pulses from the 1.5
Ge V linac. The RF bucket of this system is wider
than 15 ns. Injected bunch is accelerated to 2.7
Ge V, and then the bunch length is shortened toabout 1 ns by radiation damping. The highfrequency system (508 MHz) is then turned on toaccelerate the beam up to 6 GeV. This is why a
two-RF system is necessary.
There is only a small space for the lowfrequency cavity in the synchrotron, because it isan injection ring for the storage ring and must be
designed compactly and because the 508 MHz RF
system occupies large room in the RF section.
The low-frequency cavity also needs a large
shunt impedance because the peak RF voltage ishigh (250 kV). In this report, we show the designof the low-frequency cavity whose frequency is
42 MHz and find the optimum shape with a small
size and a large shunt impedance.
A capacitively-Ioaded coaxial type of cavity as
shown in Fig. l(a) is considered for the lowfrequency system. The cavity has a circular tuning plate on the high voltage end and acapacitive loading plate across the gap. In thedesign of this cavity, a circuit model equivalent
to the cavity makes the design easy and optimizes the structure. To calculate the cavity size
and the shunt impedance we can dissect thecavity into different parts. 1) In the calculation of
the cavity size, the cavity is divided into threeparts: a gap between the tuning plate and thecapacitive plate (axial length: Ll), a part
between the capacitive plate and the outer wall(L2), and a coaxial line (L3). These parts areapproximated to three transmission lines whosecharacteristic impedances are z., .z, and ~ asshow in Fig. l(b). They are analyzed using theboundary conditions by which voltage and current are continuous at each boundary. In thisresonator, the current 10 on the beam line is zero
because the voltage Vo is the largest, and thevoltage V3 at the shorted end is zero because of

lJ.

Zl

ril

I

Z3

~~=1~t - ±-jB-eamLine---

L1

L2

L3

-- -- - --------(a) Cavity shape'0'3vol' :;: :::3: }3(b) Equivalent transmission line
Z1. Z2 . Z3 : Characteristic impedanceFig. 1. Calculational geometry and equivalent transmission lines for the capacitively-Ioaded coaxial
type of cavity.

the resonant condition. The cavity length (L) is
calculated under the condition of a fixed resonant frequency (j):L=Ll + L2+ L3=Ll + L2+~(-~ - a)wherelight.

tan a=ZpQ, f3 = 2;1, c is the velocity of
p = cos f3A cos f3L 2 - ~: sin f3A sin f3L2Q=

i 2 cos f3A sin f3L2 + i sin f3A cos f3L2
1

In the calculation of the shunt impedance, thecavity is divided into five parts: the previous
three parts in the calculation of the cavity size,
short circuit on the coaxial line, and the rapidchange of the cross-section of an inner conductor. The losses (~oss i) are calculated in eachpart of a resonator. The shunt impedance (Rs) is
calculated from these losses.
Rs

V0

2

~~oss i

The comparison of the calculation results using
this model with those obtained by SUPERFISH2)
is shown in Table 1. The calculations of thecavity size and the shunt impedance provide
reasonable results compared with those by296

T. Yoshiyuki, et at.

Cavity Length and Shunt Impedance

42 MHz~------~2.4

104.7 emA - O.Sm~

B - 0.3 m, -- -.l~..D.. \ ~ \ \....Ll~ U \1

11 - 0,073 m~ 1.00

~

0 .99

0 .2

L2

0 .3

~

0 .4

1m)

7.3cm

Fig. 2. Calculation results of the cavity length andthe shunt impedance.

Table 1. Comparison of the calculation results obtainedby a circuit model and SUPERFISH.
(a) Calculation geometries.
Case

A

B

C

1
2
3
4
5

0.5
0.5
0.5
0.4
0.5

0.3
0.3
0.4
0.3
0.4

0.15 0.073 0.03 0.91
0.15 0.073 0.24 0.65
0.15 0.073 0.03 0.53
O. 15 0.073 0.32 0.56
0.150.10 0.35 0.65

L1

L2

L3

Cavity length(=L1 +L2+ L3)
1.013
0.963
0.693
0.953
1.10
(all units: m)(b) Calculation results.
Frequency (MHz)
Case

1
2
3
4
5

Shunt impedance (M!1)

CircuitmodelSUPERFISH

CircuitmodelSUPERFISH

42.0
42.0
42.0
42.0
42.0

41.6
41.6
41.6
41.8
40.8

2.18
1.47
1.01
0.625
1.57

2.13
1.66
1.29
0.890
1. 76

JL"" \ " " " ""3cm

JFig. 3. Shape of the 42 MHz cavity.

SUPERFISH. The results using this model as afunction of the thickness of the capacitive plate(L2) are also shown in Fig. 2. When L2 is 0.25 m,
the total cavity length is the shortest, but adecrease in the length is about 5% at most andthe shunt impedance is reduced to about 60% of
the maximum. To obtain a sufficiently large
shunt impedance and a reasonable size, the cavity dimensions are chosen to case 1 in Table 1 inview of the easiness to fabricate and the coolingof the capacitive plate. The shape of the cavity isshown in Fig. 3.
In conclusion, a circuit model shows a good
approximation for the cavity design. The lowfrequency cavity for the synchrotron is designedwith a reasonable size and a large shunt
impedance by using this model.
References
1) W. Ebeling, H. Gerke, H. Hartwig, M. N agl, H.P.

Scholz, M. Sommerfeld, and A. Zolfaghari: DESY
M-79/ 28, Dec. (1979).
2) K. Halbach and R.F. Holsinger: Part. Accel., 7, 213(1976).

297
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-25.

Conceptual Design of Linac for the RIKEN SR
K. Yamasu, H. Miyade, and M. Hara

The RIKEN SR ring uses an injector linac
system for acceleration of electrons or positrons
up to 1.5 GeV. This injector system consists ofthree parts 1):
1) Electron part: Electrons generated by anelectron gun at (;i current of 100 rnA are bunchedthrough a bunching system. They are accelerated
up to 250 MeV in the electron linac.
2) Positron part: Electrons of their peak current of 5A are accelerated up to 200 MeV and hit
a positron converter. Generated positrons arethen accelerated up to 250 MeV in a positronlinac.
3) Common part: Electrons or positrons accelerated up to 250 MeV are then injected into acommon linac and accelerated up to 1.5 MeV.
Disign parameters of this injector are summarized in Table l.
Because many breakdowns are expected tooccur in such a complex system, we hope toreduce the number of klystrons and accelerating
structures to simplify a high power RF circuit.
To optimize an accelerating unit, we calculate
an avrage accelerating field. The loaded field
gradient E(z) of a constant gradient (C.G.) section is expressed by the symbols listed in Table
1: 3 )
E(z)-_.jroPo
L /1-e+ i;o In ( 1- (1- e- f)
21'

2T

)

where z is the distance along the structure.
If we use a long structure to accelerate a beam,
the attenuation constant becomes large and wemust reduced the diameter of an exit iris, called
2a in general, to keep the field gradient constant.
In this investigation we suppose that the shuntimpedance and the merit of Q is constant and theexit '2a' is 20 mm<p for the beam size.
Figure 1 shows the dependence of the average
field gradient on the C.G. structure length when
the input power to a structure is changed and thepeak beam current is 100 mAo
The high power RF (radio frequency) source
generates a high field gradient. The most powerful pulsed klystron available today provides
35-MW output at peak. Because power loss in the

Table 1. Linac parameters.
GeneralEnergyBeam current
e-modee+modeRepetition rate
Pulse length
Regular section
Frequency
Accelerating mode
Structure type
Structure length
No. of cells
Attenuation
Shunt impedance
Filling time
Merit of Q
Range of iris diameter
Group velocity
Field gradient (100 rnA)
No. of structures
Effective length
Klystron
Peak power (effective)
Pulse width
Duty factor
Efficiency (max.)
Gain (max.)
No. of klystrons

f

L
T

ro
4
Q
2a

vg / C

Po

1.5

GeV

100
10
50
15

rnA
rnA
pps
ns

GHz
2.856
Travelling wave, 2/ 37l'
Disk loaded
constant gradient
m
2.836
81
Np
0.427
Ma/m
54.0
0.628
JLS
13,20026.00'"'-'20.00 mm,p0.022'"'-'0.009
MV/m
17.38
31
m
86.31
MW

30
6.0
0.04
44.0
47
31

JLS

%
%
dB

35.-----------------------~

E 30

:>

50MW

~ 25

'E

30MW

20

25MW

(1)

:cf! 15
(!)
"C

10

]i

5

u.

_._._+_._.

20MW
15MW
10MW

u

SMW

O~~~~,-~~~~~~~~

50 100 150 200 250 300 350 400 450 500

Structure Length (em)Fig. 1. Dependence of average field gradient on
the structure length (100 rnA loaded) in the CG.
structure.

298

K. Yamasu, et al.

high-power RF circuit is about 5 MW, and RF
power of 30 MW is supplied to an accelerating
structure.
We chose a 3-m long accelerator structure
driven by a 30-MW klystron as a unit structure,in which the field gradient is about 18 MV 1m.
The beam is accelerated up to 1.5 GeV by thelinac which has 31 klystrons and 31 structures,and the effective length of the linac is 86.3 m.
The field gradient in this unit is shown Fig. 2.
Since we cannot calculate the loaded field gradient of a quasiconstant gradient (Q.C.G.) section
analytically, we must calculate it by a numerical

180

135

c;

90

Q)

~

45
0

Q)

en

C'a

.c

-45

Q.

-90

-135

"",~_..,::e."""'

+

~

E
CI>

OmA C.G.

beam current: 100mA peak

:>
51.35
CI.I

OmAQ.C.G.

~:c<'II

17

't:I

16

c:

~ 51 .30

c:;
Gi

678

51.40,..--------------,_ _""""_""""~"'dH---l 0

> 18

5

Distance

Fig. 3. Phase orbits through the our bunchingsystem.

19~------------------------'

E

234

Normalized•u:

100mA C.G.

>~

100mA Q.C.G.

~

CI.I

51 .25

15
0

300

200

10 0

z (em)

Fig. 2.

51 .20 +--..------,,.--~--,--~--;
15
10
5
o

Field gradient along the structure.

t (ns)

analysis method using a computer.
It is required that a beam at the exit of thisinjector is stable and its energy spread is small.
A bunching system is the most important system
to decide the beam characteristics. Figure 3
shows the trajectory of the bunching beam in ourbuncher. It is clear that electrons distributed in
the phase of 140 to - 170 are bunched. 3 ) In
acceleration of a pulsed beam, the accelerating
voltage in a linac decreases with time in a transient period which corresponds to a filling timeof the beam pulse after the injection of the frontof it. This causes an additional energy spread of
the beam. The energy gain, V (t) for electrons
coming t s after the pulse front is given by thefollowing equation; 2)

Fig. 4. Transient energy gain per one structure in
short time scale.

V(t) = I YoPoL II - e- 2r - iYoL (1- e- 2r )2.
wt e- 2r + e - ~t
+ zYoL -=Q"'--_----::-----_

Fig. 5. Transient energy gain per one structure inlong time scale.

0021- e- 2r
where w is the phase frequency.
Energy gain per one structure in the transientstate is calculated from this equation. Figure 4
shows the result in a short time scale and Fig. 5
in a long time scale. When the width of the pulsed
beam is shorter enough than the structure's filling time, it is clear that the rate of the energy
spread is 0.3%/15 ns at 100 rnA and, therefore,

52~---------------------'~~.

:> 50 \
CI.I\==-:= 48.'~\.......

..·EDlI·<J-1O-- B-..g-g--....

::

~ 46

---1!1--10mA-"-0--'

100 mA

-~

~\...

Q;

~

~\
«~

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

~~

42+---~--~--..-----.---~~

0 .0

0.5

1.0

1.5

t (11 s)the beam energy gain is nearly equal to the 'unloaded' beam energy gain.
References
1) H. Miyade, K. Yoshida, K. Tsumaki, and M. Hara:

RIKEN Aceel. Prog. Rep., 21, 233 (1987).
2) P.B. Neal: M.L. Rep., No. 388 (1957).
3) J,M. Ponce de Leon and E.L. Ginzton: M.L. Rep., No.
265 (1955).

299
RIKEN Accel. Prog. Rep. 22 (1988)

V-2-26.

Positron Injection System for RIKEN SR
H. Miyade, K. Yamasu, and M. Hara

In the RIKEN SR the requirements for the
positron injection system are:1) Energy of injection into a booster synchrotron is 1.5 Ge V and its energy spread is lessthan 0.5%;
2) Efficiency of conversion from electron topositronis greater than about 0.5%; and
3) Emittance is less than 2.6 mmemrad at 1.5
GeV.
On the basis of these requirements, a positron
injection system was studied on the structure
shown in Fig. 1. The system has two solenoid
magnets; one is between a target and an accelerating section, and the other is around the accelerating section. The magnetic fields are 1.2 T and
0.2 T respectively,!) and the field distributions
are assumed to be rectangular shaped. The electric field in the accelerating section is 16.66 MV /m. 2 ) The iris diameter is 20 mm. 2 ) The distance
between the target and the first solenoid (/1) is set
Accelerating Section + Solenoid

I =_ ~

Iris Dia. : 20mm---8883388§- t

to 3 cm and that between the first and the second
solenoid (/2) is set to 25 cm tentatively,!) but they
will be optimized later. The length of the firstsolenoid (L) is chosen so that the acceptance ismaximum for the positron at an emission energyof 8 MeV. When II =3 cm and l2=25 cm, L is 4.71
cm.
Positrons emitted from the center of a target
with an emission angle of 100 mrad are in theorbits as shown in Fig. 2. When the maximum
deviation from the central axis is greater than
the iris radius of 10 mm, the positron cannot passthrough the accelerating section. Figure 3 showsthe energy dependence of the maximum emission
angle of the positron which can pass through theaccelerating section. For a positron with anemission energy of 8 MeV, the maximum emission angle is 256 mrad and the acceptance, which
is defined as a solid angle, is 0.205 sr.
The acceptance of the positron emitted at theposition apart from the target center is less thanthat at the center. Figure 4 shows the relation
between the acceptance and the distance from

~1=3cm~2~2=25cm

300,--------------,

L=4.71cm

M"o'"Fi,.1L---'-U_1.2_T-'-_ _' - -_ _O_
.2T_ _---'

-g

i

200

l
CD

Electric Fieldl,_ _ __100

16.66MV/m_ _-'--_ __ _- - 'o~-----~----~

oFig. 1. Structure of the positron injection system.
80r---------------~

1020

E (MeV)

Fig_ 3. Energy dependence of the maximum emission angle.

Initial Phase

Ro=Omm60

20 MeVa 0=1 OOmrad.

e-

.g 40

0.20
15 MeVa:20

a 0.10
8 MeV

0~~~~~C=~~~==~~~
o
5
10
15

t

z (m)

Entrance of the accelerating section

Fig. 2.

Positron orbits in the accelerating section.

o.oo+-----.---'---~

o

1

2

Rs (mm)Fig. 4. Dependence of the acceptance on the emitting position.

300

H. Miyade, et at.

the target center to the position where thepositrons are emitted. The acceptance is 0 at the
distance of 1.46 mm from the center, i.e., a
positron emitted from the position apart morethan 1.46 mm from the target center cannot passthrough the accelerating section.
When an elecron with an energy of E - (MeV)
impinges the target, the number of positrons
emitted from the target in a unit solid angle withenergies between E+ (MeV) and E+ + dE+ (MeV)
is expressed by
NdE+=2 X 10- 4 E - exp( - 8/0.35)dE+(l / sr)
0 . 6 . - - - - - - - - - - -- --0.4

h=lOcmwhere 8 is the emission angle. 4 ) When the emission energy range of the accepted positrons is 8
± 1.5 Me V3) and the energy of the impinging
electrons is 200 MeV, we obtain the conversion
efficiency of 0.45%.
For a positron with an emission energy of 8
MeV, the emittance on the tqrget is1.46 mmX256 mrad = 374 mm·mrad
Upon acceleration up to 1.5 GeV it becomes
374 mm·mradX8 MeV / 1.5 GeV=2.0 mm·mrad
Furtheremore, assuming a dilution factor of
12%,3) we obtain the emittance of 2.0 mmemrad x
1.12 = 2.2 mmemrad.
Finally, we mention the optimization of II andl2' For II it is clear that the smaller II makes theacceptance greater, i.e., the optimized value of II
is O. Figure 5 shows the dependence of the conversion efficiency on l2' When II is 0- 3 em, theoptimized value of l2 is 25------40 em.

0.2

References
0.0+----~---.----~------1o100
12 (em)200

Fig. 5. Dependence of the conversion efficiency on/Z.

1) R. Chehab, S. Fukuda, and A. Asami: KEK preprint,
87-169, Mar. (1988).
2) K. Yamasu, H. Miyade, and M. Hara: Proc. 13th
Linear Accelerator Meeting in Japan, p. 236 (1988).
3) Conceptual Design Report, ANL·87-15, Apr. (1987).
4) J. Haissinski: Nucl. Instrum. Methods, 51, 181 (1967).

301
RIKEN Accel. Prog. Rep. 22 (1988)

VI.

RADIATION MONITORING
1.

Routine Monitoring of the Cyclotron, RILAC, and TANDETRON
I. Sakamoto, S. Fujita, M. Yanokura, T. Kobayashi,

O. Kurihara, T. Katou, M. Miyagawa, S. Kagaya,
S. Shinohara, M. Iwamoto, and I. Kohno

The present report describes the results ofroutine radiation monitoring carried out for the
cyclotron, RILAC, and T ANDETRON from January to December 1988.
Aspects of the leakage radiation from thecyclotron are described in a succeeding report. 1)(1)
Residual activities of the cyclotron
In August 1988, the dose rates due to residual
activities of the machine were measured 19 days
after the scheduled shutdown; the maximum irradiation dose rates measured was 10 mR/ h at 50
cm apart from a septum. No external exposure
doses were detected for two workers during
replacement of the septum.
(2) Contamination in the cyclotron building
The surface contamination has been kept
below 10- 5 ,uCi/cm2 on the floors of the cyclotronbuilding. The radioactive nuclides found by

y-ray spectrometry were 183Re and 65Z n in thecyclotron vault, and 137CS in the waste-storage
room. The contamination was wiped off twice ayear. Immediately after this decontamination,
the activities on the floor of most of the above
places were reduced below 10- 7 ,uCi/cm2.
When radioactive substances were handled in
the hot laboratory and chemical laboratories, theair in a draft chamber was activated. The air inthe draft chamber was exhausted; and the radioactivity in the exit was found to be 10- 13 ,uCi/
cm 3 .
(3) Drainage
The radioactivities in drain water from thecyclotron and the linac buildings were found to
be of the order of 10- L 10- 7 ,uCi/cm 3. The total
activity in aqueous effluents was 1.2 ,uCi, in
which the main radioactive nuclide was 137CS, theTable 1. Annual external exposure doses received by RIKEN accelerator workers from January to December 1988.
N umber of persons
Workers

Dose
undetectable

10-100(mrem)> 100(mrem)

Total

Collective
dose(mrem)

8

0

0

8

0

7

2

0

9

30

Ring cyclotron operation and maintenance groups
Cyclotron operation and maintenancegroupsLinac operation and maintenancegroupsNuclear physicists
Accelerator physicists
Physicists in other fields
Nuclear chemists
Radiation chemists
Biological chemists
T ANDETRON workers
Health physicists

8

0

0

8

0

59
19 .
54
20
4
14
13
6

3
1
2
13
0
0
0
0

0
1
0
0
0
0
0
0

62
21
56
33
4
14
13
6

30
180
40
570
0
0
0
0

Total

212

21

1

234

850

Average annual dose per person, 3.6 mrem; Maximum individual annual dose was 110 mrem.

302

1. Sakamoto, et al.

radioactivity was 0.4 ]lCi, and the other nuclides
found by y-ray spectrometry were 71As and 57CO.
(4) Radiation monitoring for RILAC andTANDETRON
The leakage radiation during operation of
RILAC was measured outside the linac building
every three months. No leakage of y rays andneutrons from the linac buiding was detected. No
contamination due to residual activities wasfound on the floor of control area and conditioning air in the linac building.
X-ray monitoring was carried out for TANDETRON, when a copper target was bombarded
with 1.6 MeV H+ ions of 0.1 nA, the maximum
irradiation dose rates measured around TANDETRON was 0.2 mR/ h. No leakage X-rays
were detected around the target chamber andoutside the T ANDETRON room.
(5) Personnel monitoring

The number of RIKEN accelerator workers
increased to 2 times of that in the preceding
period.
The external exposure dose for personnel were
measured by using y ray and neutron film
badges. The dose received by accelerator
wor kers from January to December 1988 areshown in Table 1. The collective y-ray doses toall workers was 850 man-mrem. The collective
dose owing to thermal and fast neutron exposures was below the detection limit. Because
nuclear chemists began experiments in the hotlaboratory in February, the collective dose forthe workers in this period increased to 4.7 timesof the value in the preceding period.
Reference
1) 1. Sakamoto, S. Fujita, and 1. Kohno: This Report, p.
303.

303
RIKEN Accel. Prog. Rep. 22 (1988)

VI-2.

Leakage-Radiation Measurements in the Cyclotron Building
I. Sakamoto, S. Fujita, and I. Kohno

Leakage radiation was measured at various
points in the cyclotron building in July 1988,
when a target placed on the beam line No.2 wasbombarded with 40-MeV helium ions at a beam
intensity of 2 pA.
y-Ray dose rates were measured with an ionization chamber survey meter, and doseequivalent rates for fast and slow neutrons were
measuered with a "rem counter."* The results
are shown in Fig. 1.

The leakage doses measured during January
and December 1988 with y-ray and neutron film
badges placed at two positions (point A and B in
Fig. 1) on the underground passage are shown in
Table l.
Of the dose values at point B measured every
month, the maximum total dose of 1,300 mrem
was observed in November, when the values for
y-rays, and thermal and fast neutrons were 290,
30, and 980 mrem, respectively.
!

!

!

!

!

!

012345m

Experimental area (L) :
1

0:
0 x
1

o

~

-

I

1

Underground passage~' 010: x
-

Ax1.8

I

OIX

Q: t

o

5.2

[

UP

Q

1
1
1

,WT

ON

: 0
:Q

0

1

~1oI.IoI.I.~__ J

Hand foot cloth monitor

Control room
Basement

Ground plan

Operating conditions

Dose unit

Ecr: 40 MeV

y ray: mR/ h

Beam line: No. 2

Neutron: mrem/ h (underlined value)

Target: Ir

Fig. 1. Leakage-radiations (neutrons and y rays) in the cyclotron building.
* A Neutron Rem Counter NSNI manufactured by Fuji
Electoric Co., Ltd. Japan.

1. Sakamoto, et at.

304

Table 1. Leakage-radiation doses (in mrem) on the underground passage of the c yclotron building during
January and December 1988.
Point B*

Point A*y raysThermalneutrons(mrem)

Fast
neutrons(mrem)

310
50
320
350
280
50
490
0
40
320
20
270

10
10
10
10
20

10
30
60
40
100
30

330
90
390
400
400
80

0
0
0
0
0
0

0
0
0
0
0
0

0
0
10
20
10
0

70
0
20
70
0
40

580
0
60
420
20
330

0
0
0
0
290
0

0
0
0
0
30
0

10
0
0
0
980
0

0
0
10
20
10
0
10
0
0
0
1,300
0

2,500

130

470

3,100

290

30

1,030

1,350

Month
(mrem)
1.88'
2
3
4
5
6
7
8
9

10
11
12
Total

0
20
0
0
30
0
20

Total

y rays(mrem)(mrem)

Thermalneutrons(mrem)

Fast
neutrons(mrem)

Total(mrem)* See Fig. 1.

The high fast-neutron doses observed at point
A in May, June, and October and at point B in
November were 100, 70, 70, and 980 mrem, respectively. The increase in the neutron dose at point
B was due to high intensity irradiation in the
beam line No. 4 which was bombarded with
22-MeV helium ions at a beam intensity of 250

nA; the beam intensity cyclotron users frequently
use on this beam line was 7- 8 nA. At point A, thehigh fast-neutron doses were due mainly to activation analysis and radioisotope production carried out on the beam line No. 2 during these
periods.

305

RIKEN Accel. Prog. Rep. 22 (1988)

VI·3.

Shielding Calculation for the Facility of RIKEN Ring Cyclotron
Using RILAC as an Injector
T. Shikata, N. Nakanishi, T. Kosako, and H. Kamitsubo

Since December 1986, RIKEN Ring Cyclotron
has been operated with a linear accelerator forheavy ions, RILAC, as an injector. This report
describes a calculation of the shielding design forthis coupled operation.
Neutrons emitted by 12C (75 MeV/u, 6xI0 12
pps) on a thick 56Fe target was chosen as a source
for the shielding calculation. The energy spectrum is given in Refs. 1 and 2. This energy ofcarbon ions is slightly higher than the utmost
energy in the coupled operation. A onedimensional discrete ordinate code ANISN -JR3)
was used in the calculation.
Shielding is executed by an iron-concrete besm
dump combined with a concrete wall. The dose
rate at the distance L from a point source can beobtained by multiplying the dose rate for the. normal incidence on a iron-concrete double layerslab by 1/L 2 (calculation by a slab model); theresults are shown in Fig. 1. These charts weremade for designing neutron shielding. The summed thickness of the concrete part of a beam
dump and a wall is taken as the abscissa and thedose rate at L multiplied by L 2 is taken as theordinate. Using this chart, we can estimate thethickness of a concrete part and an iron part tosuppress the dose rate below an allowable level,with an arbitrary thickness ratio. When a sourceis surrounded with a shield, the calculation by aslab model using ANISN does not give a correct
result. For instance, considering isotropic neutron sources which have an energy distribution

N

E

Iron slab thickness

Iron slab t hickness

o m

o m
---- - ... - --- ----.

1- - - - -------- - ..... --

0.3 m
0.6 m
0 .9 m4

2

5

Concrete slab thickness em)
(a)

6

0.3 m
0.6
0 .9 m

3

2

4

5

6

Concrete slab thickness em)(b)Fig. 1. (a) Neutron dose rates for a point source outside the concrete wall. L is the distance from the source and B
is a specified angular interval. (b) Photon dose rates for a point source outside the concrete wall.

306

T. Shikata, ct al.

12~180 0-----------

1.5-------~--===========~

~

4

3

8

6

5

Radius, Jl

9

10

(m)

(a)

Fig. 2. Concentric spherical shell.

of neutrons ejecting into angular ranges 0°-30°,30°-60°, 60° -120°, and 120°-180°, we carried out
following calculation. We considered a sphericalshell of an inner radius of l, which has a beam
dump composed of a vacancy of 10 cm in radius,
an iron shell of 20 cm in thickness, and a concrete
shell of 30 cm in thickness at the center, as illustrated in Fig. 2. The calculated neutron dose rate
outside the shell, D sp , which can be obtained
exactly by using ANISN-JR, was compared withthat obtained from the slab model describedabove, Ds1 • A similar calculation was also carriedout for a monochromatic neutron sources. Neutron dose rates outside the shell were denoted as
Dsp' and DSI', corresponding to the dose rates forthe spherical system and from the slab model,
respectively. The ratios, Dsp/ DSI and Dsp' / DSI',
are shown in Fig. 3. In this shielding system, thedose rate obtained from the slab model are underestimated, especially for low-energy neutrons.
Thus, in general, the dose rate calculated bymeans of the slab model must be multiplied by aproper factor, which cannot always be obtainedcorrectly and has to be determined by a physicalconsideration suited to each shielding system.

-

C>

0.
(/)

40 MeV-35 MeV

90 MeV-80 MeV

3

4

5

6
Radius, Jl

8

10

(m)

(b)

Fig. 3. (a) Dsp / Ds1 . Dsp stands for the neutron dose
rate outside a concrete shell of 2 m in thickness,
which encloses a beam dump composed of avacancy of 10 cm in radius, an iron shell of 20 cm
in thickness, and a concrete shell of 30 cm inthickness. DSI stands for the neutron dose rate at
the same point calculated by means of the slab
model. (b) Dsp' / Ds1 '. Ds/ and Dst' have similar
meanings as Dsp and DSIJ respectively, for monochromatic neutron source.

References
1) T.A. Gabriel, R.T. Santro, H.W. Bertini, and N.M.
Larson: ORNL-TM-4334 (1973).
2) T. Nakamura: INS-NUMA-5 (1977).
3) K. Koyama, Y. Taji, K. Minami, T. Tsutsui, T. Ideta,
and S. Miyasaka: JAERI-M 6954 (1977).

307
RIKEN Accel. Prog. Rep. 22 (1988)

VI-4.

Radiation Monitoring in RIKEN Ring Cyclotron Facility

s. Fujita, I. Sakamoto, T. Inamura, and H. Kamitsubo
The Radiation Safety Control System (RSCS)
worked steadily from January to December 1988,
performing radiation monitoring continuously
and automatically.
Additional beam lines became available forexperiments in the experimental vaults D, E2, E3,
and E7. Figure 1 shows the indoor monitoring
positions and the beam lines in the RIKEN Ring
Cyclotron facility.
On November 24-29, an experiment was carried out with a 14N beam of 42 MeV lu, thehighest energy used this year, in an experimental
vault E7. Figure 2 shows the daily variations indose rates during this experiment recorded on:(a) an ionization chamber in the RIKEN Ring
Cyclotron vault; (b) an ionization chamber in anexperimental vault E7; (c) an ionization chamberin the A VF Cyclotron vault; (d) a BF3 counter inan experimental vault E7; and (e) a BF 3 counterin the AVF Cyclotron vault. Slight leakage neutrons were recorded in the AVF vault (Fig.2(e)).
but no leakage gamma rays were detected (Fig.
2(c)). No leakage gamma rays and no neutrons
from RIKEN Ring Cyclotron and E1, D, E2, E3,
and E7 vaults were detected by environmental
monitors.
Here we shall present a typical example ofresidual activities measured in the facility. Strongest residual activities were detected on the
beam lines. Table 1 summarizes dose rates on the
beam lines, measured with aNal-scintillation
survey meter and an ionization-chamber survey
meter.
On December 14- 16, 11 days after the experiment performed with a 14N beam of 42 MeV l u,
the dose rates due to residual activities of
RIKEN Ring Cyclotron were measured with an
ionization-chamber survey meter. The results
Table 1. Summary of residual activities measured along the beam lines. Alphabets indicate
detection points. (See Fig. 1.)

Detection
point

NaI!
scintillation
surveymeter(mR/ h)1.7

A
B

Fig. 1. Layout of RIKEN Ring Cyclotron facility
as of 1988. Monitoring positions are denotedby x. Residual-activity detection points on the
beam lines are denoted by alphabets.

Ionizationchamber survey
meter(mR/ h)

3.0

C

1.5

D

0.03

E
F

0.4
0.01

G
H

0.3
0.25

I

0.25

J
K
L
M

0.15
0.6
0.05
0.02

N

0.4

o

3.0

1.0

Date

Nov. 19
Nov. 19
Aug. 1
Dec. 5
Dec. 5
Aug. 1
Nov. 19
Dec. 5
Dec. 5
Dec. 5
Dec. 5
Nov. 7
Nov. 7
Nov. 7
Nov. 7

308

S. Fujita, et al.

10

4

..c:

"0::

::t 1 0

>,
cd

3

2

10

...
10

10

1

4

..c:

~ 10

..c:

"-0::
::t 1 0

3

103
2
10

I..

~
'"

10

c::

>,

10

cd

o

2

.....

...

10

'"
Z

10

1

o

-I

10
l0 2~~~~~~+'y~~~~~~~~~~

1

10

4

2

..c:

..c:

"-E

"-0::

'"

::t

I..

10

0

::t
c::

>,

cd

o

-I

...

10

...
1

10

D ate

D a teFig. 2. Daily variations in the radiation level measured in RIKEN Ring Cyclotron facility. Detectors are (a) an
ionization chamber in RIKEN Ring Cyclotron vault, (b) an ionization chamber in the experimental vault E7,(c) an ionization chamber in the AVF Cyclotron vault, (d) a BF3 counter in the experimental vault E7, and (e)a BF 3 counter in the A VF Cyclotron vault.

//I;
MDP3

fj

Fig. 3. Detection points around RIKEN Ring Cyclotron. EDC, an electrostatic deflection channel;
MDC2, a magnetic deflection channel; MDP1, amain differential probe 1; MDP2, a main differential probe 2; MDP3, a main differential probe 3.
Figures indicated are dose rates in units of mR/ h.

are shown in Fig. 3, together with the detection
positions. The dose rates increased about 2-10
times that of a previous report,l) depending on
the positions. The maximum dose rate was foundto be 6.0 mR/h at EDC, an electrostatic deflection

channel of the beam extraction region.
Reference
1) S. Fujita, 1. Sakamoto, T. Inamura, and H. Kamitsubo: RIKEN Accel. Prog. Rep., 21, 258 (1987).

309

VII.

LIST OF PUBLICATIONS

1.

Accelerator development and accelerator
physics
1) S.H. Be, Y. Morimoto, H, Sakamoto, and .
S. Y okouchi: "Conceptual Design of the
Vacuum System for the 6 Ge V Storage
Ring," American Vacuum Soceity Series 5,
Upton, N. Y., p. 7 (1988).
2) Y. Morimoto, H. Sakamoto, S. Yokouchi,
and S.H. Be: "Conceptual Design andThermal Analysis of the Crotch at the 6
GeV Storage Ring," American Vacuum
Soceity Series 5, Upton, N. Y., p. 327(1988).
3) S.H. Be, S. Nakajima, K. Ikegami, N.
Ohsako, K. Morimoto, T. Kikuchi, and S.
Morishita: "New Cryopumps for a
Resonator of the RIKEN Ring Cyclotron,"
Vacuum, 38, 543 (1988).
4) Y. Yano: "Initial Operation of RIKEN
Ring Cyclotron," Proc. 3rd Jpn.-Chin. Jt.
Symp. Accelerators for Nuclear Scienceand Their Applications, Wako, Nov. 1987,
p. 6 (1988).

2.

Nuclear physics and nuclear instrumentation
1) S. Yamaji, H. Hofmann, and R. Samhammer: "Self-Consistent Transport Coefficients for Average Collective Motion atModerately High Temperatures," Nucl.
Phys., A475, 487 (1988).
2) S. Kato and 16 others including T. Suzuki:"N eutrino Mass Studied by Measuring
Tritium Beta-Decay with an Iron-Free
Beta-Ray Spectrometer," Nucl. Phys.,A478, 433 (1988).
3) 1. Tanihata: "Nuclear Stracture Studies
Using High-Energy Radioactive Beams,"
Nucl. Phys., A478, 795c (1988).
4) T. Motobayashi, S. Satoh, H. Murakami,
H. Sakai, N. Matsuoka, T. Saito, T. Noro,
K. Hosono, A. Okihana, M. Ishihara, H.
Okamura, and A. Hatori: "Tensor Analyzing Power Measurement of IH(d, 2He)nReaction at 70 MeV," Nucl. Phys., A481,
207 (1988).
5) K. Asahi, M. Ishihara, T. Ichihara, M.
Fukuda, T. Kubo, Y. Gono, A.C. Mueller,
R. Anne, D. Bazin, D. Guillemaud-Mueller,
R. Bimbot, W.-D. Schmidt-Ott, and ].
Kasagi: "Production of Spin-Aligned Unstable Nuclei in the Projectile Fragmentation at Intermediate Energies," Nucl.

Phys., A488, 83c (1988).
6) 1. Tanihata: "Nuclear Studies with
Secondary Radioactive Beams," Nucl.
Phys., A488, 113c (1988).
7) H. Kawakami and 20 others including T.
Suzuki: "Study of Energy Loss of 18 ke V
p-Rays in a Langmuir-Blodgett Thin
Film," Nucl. Instrum. Methods Phys. Res.
A, 264, 511 (1988).
8) T. Doke, H.J. Crawford, A. Hitachi, ].
Kikuchi, P.]. Lindstrom, K. Masuda, E.
Shibamura, and T. Takahashi: "LET
Dependence of Scintillation Yields in Liquid Argon," Nucl. Instrum. Methods Phys.
Res. A, 269, 291 (1988).
9) T. Motobayashi, S. Satoh, H. Murakami,
H. Sakai, and M. Ishihara: "A Silocon
Counter Array for 2He Detection," Nucl.
Instrum. Methods. A, 271, 491 (1988).
10) T. Nakagawa and W. Bohne: "A Compact. and Gridless Channel Plate Start Detector," Nucl. Instrum. Methods. A, 271, 523(1988).
11) T. Kajino, H. Toki, K.-l. Kubo, and 1.
Tanihata: "NucIear Matter Radii of 7Be
and 7Li and Astrophysical S-factor for
Radiative Alpha-Capture Reactions,"
Phys. Lett. B, 202, 475 (1988).
12) 1. Tanihata, T. Kobayashi, O. Yamakawa,S. Shimoura, K. Ekuni, K. Sugimoto, N.
Takahashi, T. Shimoda, and T. Sato:"Measurement of Interaction Cross Sec. tions Using Isotope Beams of Be and B,
and Isospin Dependence of the Nuclear
Radii," Phys. Lett. B, 206, 592 (1988).
13) H. Harada, T. l\1urakami, K. Yoshida, ].
Kasagi, T. Inamura, and T. Kubo:"Intruder Deformed Bands in llOSn and
112Sn," Phys. Lett. B, 207, 17 (1988).
14) M. Oshima, E. Minehara, S. Ichikawa, H.
Iimura, T. Inamura, A. Hashizume, H.
Kusakari, and S. Iwasaki: "Signature
Dependence of MI and E2 Transition Probabilities for the i 13/2 Rotational Band in
16 1Dy," Phys. Rev. C, 37, 2578 (1988).
15) R.]. Peterson, M. Yasue, M.H. Tanaka, T.
Hasegawa, N. Nishimura, H. Ohnuma, H.
Shimizu, K. Ieki, H. Toyokawa, M. Iwase,]. Iimura, and S.l. Hayakawa: "25Mg(3He,d)26 Al to High Spin States," Phys. Rev. C,
38, 1130 (1988).
16) S. Hayashi, Y. Miake, T. Nagae, S.

310

N agamiya, H. Hamagaki, O. Hashimoto,Y. Shida, 1. Tanihata, K. Kimura, O.
Yamakawa, T. Kobayashi, and X.X. Bai:
"Production of Pions and Light Fragments
in 0.8 A GeV La + La Collisions," Phys.
Rev. C, 38, 1229 (1988).
17) R.J. Peterson, M. Yasue, M.H. Tanaka, T.
Hasegawa, N. Nishimura, H. Ohnuma, H.
Shimizu, K. Ieki, H. Toyokawa, M. Iwase,
J. Iimura, and S.l. Hayakawa: "Forbidden(p, d) Pickup to Stretched States of 26AI,"
Phys. Rev. C, 38, 2026 (1988).
18) T. Kobayashi, O. Yamakawa, K. Ornata,
K. Sugimoto, T. Shimoda, N. Takahashi,
and 1. Tanihata: "Projectile Fragmentation of the Extremely Neutron Rich Nuclei
llLi at 0.79 GeV / nucleon," Phys. Rev. Lett.,
60, 2599 (1988).
19) Y. Nojima, K. Matsuta, T. Minamisono, K.
Sugimoto, K. Takeyama, K. Ornata, Y.
Shida, 1. Tanihata, T. Kobayashi, S.
N agamiya, K. Ekuni, S. Shimoura, J .R.
Alonso, G.F. Krebs, and T.J.M. Symons:"Plaraization Creation by Beam-Foil
Interactions fo'f Projectile Fragments
Produced in High-Energy Heavy-Ion Collisions and NMR Detection of Short-Lived,.B-Emitting 39Ca," Nucl. Instrum. Methods
Phys. Res. B., 33, 193 (1988).
20) K. Sato and S. Yoshida: "Studies of
Nuclear Second Moments for PreEquilibrium Nuclear Reaction Theories-Extension to Finite-Range Residual
Interaction," Z Phys. A, 330, 265 (1988).
21) N. Hasebe, Y. Ezawa, H. Yoshii, and T.
Yanagimachi: "Charge Waveform of a
New Two-Dimensional Position Sensitive
Silicon Detector," Jpn. ]. Appl. Phys., 27,
816 (1988).
22) H. Kawakami and 19 others including T.
Suzuki: "Preparation of Low-Energy Reference Electron Source with 169Yb," ].
Appl. Phys., 27, 1488 (1988).
23) T. Motobayashi, S. Satoh, H. Murakami,
H. Sakai, N. Matsuoka, T. Saito, T. Noro,
K. Hosono, A. Okihana, M. Ishihara, H.
Okamura, and S. Hatori: "Tensor Analyzing Power of the (d, 2He) Reaction on 12C
at 70 MeV," ]. Phys. G, 14, L137 (1988).
24) H. Kawakami and 16 others including T.
Suzuki: "Neutrino Mass and End-Point
Energy of 3H ,.B-Decay," ]. Phys. Soc. JPn.,
57, 2873 (1988).
25) 1. Tanihata: "Nuclear Structure Studies
Using Beams of Radioactive Nuclei,"Proc. 5th Int. Conf. Nuclei Far from Stabil-ity, Rosseau Lake, Ontario, Canada, Sep.
Proc., 164, 213 (1988).
26) W. Bohne, H. Morgenstern, K. Grabisch,
T. Nakagawa, and S. Proschitzki: "Critical Excitation Energy in Fushion Evaporation Reaction," Proc. J AERI Int. Symp.
Heavy Ion Reaction Dynamics in Tandem
Energy Region, Universal Press, Tokyo, p.
227 (1988).
27) M. Yasue and T. Wada: "A Guid Note forSpectral Analysis in the S-3500 System,"
INS-Report, p. 670 (1988).
28) 1. Tanihata: "Nuclear Structure Studies
Using Beams of Radioactive Nuclei,"Proc. RIKEN -IN2P3 Symp. Heavy-Ion
Collisions, Shimoda, Oct. 1987, eds. M.
Ishihara and S. Yamaji, p. 82 (1988).
29) T. Shinozuka and K. Asahi: "Report on theFifth International Conference on Nuclei
Far from Stability," Butsuri, 43, 637 (1988)(in Japanese).
3. Atomic and solid-state physics
1) Y. Kanai, T. Kambara, Y. Awaya, B.
Sulik, N. Stolterfoht, and Y. Yamazaki:"K-LL Auger Spectra of Nitrogen Projectiles," At. Collision Res. JPn., 14, 64 (1988).
2) T. Kambara, T. Mizogawa, Y. Awaya, Y.
Kanai, R. Schuch, and K. Shima: "Impact
Parameter Dependent Probabilities of Au
L3-Shell Ionization by 1 MeV / amu Ar
Ions," At. Collision Res. JPn., 14, 66 (1988).
3) T. Mizogawa, Y. Awaya, T. Kambara, Y.
Kanai, M. Kase, H. Kumagai, and K.
Shima: "Charge-Equilibration Processesof 50-MeV Ar Ions Passing through Solid(C Foils) and Gaseous (CH 4 ) Targets," At.
Collision Res. JPn., 14, 68 (1988).
4) Y. Awaya, K. Hino, Y. Kanai, A. Hitachi,
H. Vogt, K. Kuroki, and Y. Yamazaki:"Momentum Distribution of Be 2s Electrons Measured by a Radiative Electron
Capture Process," At. Collision Res. JPn.,
14, 71 (1988).
5) Y. Kanai, T. Kambara, T. Chiba, and Y.
Awaya: "Facilities for Atomic Physics at
RIKEN Ring Cyclotron," At. Collision Res.
JPn., 14, 91 (1988).
6) H. Tawara, T. Tonuma, and T. Matsuo:"Multiply Charged Ions from Solid
Produced under Energetic Heavy Ion
Impact," Nucl. Instrum. Methods B, 30, 603(1988).
7) K. Shima, E. Nakagawa, T. Kakita, M.
Yamanouchi, Y. Awaya, T. Kambara, T.
Mizogawa, and Y. Kanai: "Projectile

311

Atomic Number Dependence of Equilibrium Charge States for 1 and 2 MeV lu
Ions Passing through a Carbon Foil,"
Nucl. Instrum. Methods B, 33~ 212 (1988).
8) S. Karashima, K. Hino, and T. Watanabe:"Charge Equilibrium of Relativistic Uranium Ions in Matter," Nucl. Instrum.
Methods B, 33, 227 (1988).
9) K. Ando, S. Kohmoto, Y. Awaya, H.
Kumagai, T. Tonuma, and S. Tsurubuchi:"Beam-Foil Experiments on Lifetime andSpectra of · Highly Ionized Aluminum
Ions," Nucl. Instrum. Methods B, 33, 239(1988).
10) A. Koyama, H. Ishikawa, and Y. Sasa:"Energy Spectra of AI-LVV Auger Electrons Induced by Grazing Angle Incident
Fast Heavy Ion Impact," Nucl. Instrum.
Methods B, 33, 308 (1988).
11) K. Hino and T. Watanabe: "Angular
Distribution and Linear Polarization of
X-Rays Induced by Radiative Electron
Capture Process," Nucl. Instrum. Methods
B, 33, 314 (1988).
12) A. Koyama, H. Ishikawa, Y. Sasa, O.
Benka, and M. Uda: "Depression of Yields
of Low Energy Secondary Electrons Induced by Impact of Heavy Ions with HighElectric Charges," Nucl. Instrum. Methods
B, 33, 338 (1988).
13) A. Koyama, H. Ishikawa, Y. Sasa, O.
Benka, and M. Uda: "High Charge Effects
on Electron Excitations in Metal Targets
for AR12+ Impact Compared with Thosefor He2+ Impact," Nucl. Instrum. Methods
B, 33, 341 (1988).
14) K. Fujima, H. Adachi, and M. Kimura:"The Charge Transfer Collision between a
Low Energy Ion and a Solid Surface,"
Nucl. Instrum. Methods B, 33, 455 (1988).
15) K. Aono, M. Iwaki, and S. Namba: "Luminescence During Eu-Implantation Into Calcium Fluoride," Nucl. Instrum. Methods
Phys. Res. B, 32, 321 (1988).
16) E. Yagi, M. Iwaki, K. Tanaka, 1. Hashimoto, and H. Yamaguchi: "Behavior of
Krypton Atoms in Aluminium," Nucl. Instrum. Methods Phys. Res. B, 33, 724 (1988).
17) S. Nakamura, E. Yagi, T. Osaka, and M.
Iwaki: "Lattice Disorder and Behavior of
Implanted Atoms in In-Implanted Ti0 2(Rutile)," Nucl. Instrum. Methods. Phys.
Res. B, 33, 733 (1988).
18) E. Yagi, H. Sakairi, A. Koyama, and R.R.
Hasiguti: "Recovery and Reverse Annealing of Proton- and a-Particle-Irradiated

CU3Au at Low Temperatures" (Extended
Abstract), Proc. 3rd Sino-J pn. Symp.
Metal Physics and Physical Metallurgy,
Shanghai Iron and Steel Res. Inst., Shanghai, p. 1 (1988).
19) E. Yagi, S. Nakamura, F. Kano, T.
Kobayashi, K. Watanabe, Y. Fukai, and T.
Matsumoto: "Hydrogen Trapping by
Solute Atoms in Nb-Mo Alloys as Observed by the Channeling Method" (Extended
Abstract),Proc. 3rd Sino-Jpn. Symp.
Metal Physics and Physical Metallurgy,
Shanghai Iron and Steel Res. Inst., Shanghai, p. 49 (1988).
20) H. Kawakami and 20 others including T.
Suzuki: "Precise Measurement of Ag KLM
and KLN Auger Spectra," Phys. Lett. A,
127, 175 (1988).
21) S. Hara, H. Fukuda, T. Ishihara, and A.V.
Matveenko: "Hyper-Radial Adiabatic
Expansion for a Muonic Molecule dt,u ,"Phys. Lett. A , 130, 22 (1988).
22) R. Kadono, K. Nishiyama, K. N agamine,
and T. Matsuzaki: "Muon Diffusion in
Pure Bismuth: Evidence for an Extended
Muonic State,"Phys. Lett., 132, 195 (1988).
23) T. Watanabe and K. Hino: "Photon Emission Processes Induced by lon-Atom Collisions," Indian]. Phys., 62B, 278 (1988).
24) S. Kubota, M. Itoh, ]. Ruan, S. Sakuragi,
and S. Hashimoto: "Observation of Interatomic Radiative Transition of ValenceElectrons to Outermost-Core-Hole Staes in
Alkali Halides," Phys. Rev. Lett., 60, 2319
(1988).
25) S.M. Younger, A.K. Harrison, K. Fujima,and D. Griswold: "Quantum Calculationsof the Electronic Structure of a ManyAtom Plasma," Phys. Rev. Let., 61, 962(1988).
26) M. Iwai, 1. Shimamura, and T. Watanabe:"Structure of the Integral Cross Sections
for Excitation in Ion-Atom Collisions Calculated in the Plane-Wave Born Approximation," Phys. Rev. A, 37, 729 (1988).
27) X. Fang, X. Zhang, Q. Ma, Y. Liu, and T.
Watanabe: "Calculation of the ElectronStripping Cross Sections of Ne Charged
Ions by Proton Impact," Phys. Rev. A, 38,
497 (1988).
28) E. Yagi, H. Sakairi, A. Koyama, and R.R.
Hasiguti: "Isochronal Annealing ofProton- or a-Particle-Irradiated CU3Au at
Low Temperatures," Phys. Rev. B, 38, 3189
(1988).
29) T. Matsuo, T. Tonuma, M. Kase, T. Kam-

312

bara, H. Kumagai, and H. Tawara: "Production of Multiply Charged Ions from CO
and CO 2 Molecules in Energetic Heavy-Ion
Impact," Chem. Phys., 121, 93 (1988).
30) H. Sato, M. Kimura, and K. Fujima: "Elastic and Momentum Transfer Cross Sections in Electron Scattering by Water
Molecules," Chem. Phys. Lett., 145, 21(1988).
31) T. Matsuo, H. Shibata, ]. Urakawa, M.
Sekiya, T. Kambara, M. Kase, and Y.
Awaya: "Ar L-MM Auger Spectra in Energetic Ar4+ + Ar Collisions," ]. Phys. B: At.
Mol. Opt. Phys., 21, 1791 (1988).
32) T. Munakata and T. Watanabe: "Studies
of Chemical Reactions by Molecular
Beams," Parity, 3, 38 (1988) (in Japanese).
33) K. Yano, H. Oyama, Y. Sakamoto, and M.
Yanokura: "Erosion of Graphite by
Atomic Hydrogen,"]. Vac. Soc. lPn., 31(5),445 (1988).
34) M. Wakasugi, T. Horiguchi, M. Koizumi,
and Y. Yoshikawa: "Hyperfine Structurenear 13-1 Band Head in the B-X Transition of 12712," ]. Opt. Soc. Am. B, 5, 2298
(1988).
35) K. Hino and T. Watanabe: "Radiative
Electron Capture Processes in the
Relativistic Incident Energy Region,"
Butsun', 43, 759 (1988) (in Japanese).
36) T. Matsuzaki, K. Ishida, K. Nagamine, Y.
Hirata, and R. Kadono: "Obsevation ofRadiative Transition Photons in the /1Transfer Process for Liquid D2 with 4He
Impurity," Muon Catalyzed Fusion, 2, 217(1988).
37) T. Tonuma, T. Matsuo, M. Kase, T. Kambara, H. Kumagai, S.H. Be, I. Kohno, and
H. Tawara: "Multiple Ionization by Energetic Heavy Ion Collisions-An Evidenceof the Innershell Electron Transfer inHighly Charged Recoil Ion Production," inHigh Energy lon-Atom Collisions, eds. D.
Berenyi and G. Hock, Springer, p. 488(1988).
38) Q.-C. Ma, X.-X. Zhang, Y.-Y. Liu, and T.
Watanabe: "Formation of (J.l+/1-) in /1+(/1-p) Collision and the Scaling Rule,"
Chin. ]. Nucl. Phys., 9, 351 (1988) (inChinese).
39) E. Yagi: "Application of Ion Beam
Analisis to Materials Science," Bull. lPn.
Inst. Met., 27, 241 (1988) (in Japanese).
40) K. Hino, and T. Watanabe: "Radiative
Electron Capture Processes in Relativistic
Impact Energy Region," Bull. Phys. Soc.

lPn., 43, 759 (1988) (in Japanese).
41) K, Fujima: "Atomic Models for Hot Dense
Plasmas," Inst. Plasma Phys., Nagoya
Univ., Rep. IPPJ-AM-57, p. 1 (1988).
4.

Radiochemistry, radiation chemistry andradiation biology
1) T. Takahashi, F. Yatagai, T. Katayama,
S. Konno, K. Nakano, I. Kaneko, and T.
Kasuya: "Position Determination by Laser
Marks of Biological Samples Placed on a
Plastic Track Detector and Inactivation of
B. Subtilis Spores by a Single Heavy Ion,"
lPn. ]. Appl. Phys., 27, 2181 (1988).
2) H. Sunaga, T. Agematsu, R. Tanaka, K.
Yoshida, and I. Kohno: "Dosimetry by a
Cellulose Triacetate Film Dosimeter inProton-Beam Irradiation," Radioisotopes,
37, 84 (1988) (in Japanese).
3) T. Takahashi, T. Katayama, F. Yatagai,
S. Konno, I. Kaneko, T. Kasuya, T. Doke,and H. Ohashi: "The Inactivation of Bacterial Spores by a Single Heavy Ion andPreparation for Experiments in a Spacecraft," ]. Radiat. Res., 29, 37 (1988).
4) T. Takahashi, F. Yatagai, T. Katayama,
and I. Kaneko: "Biological Effects of HZEParticles in Cosmic Rays and Experimental Programme," Space Environ. Manit., 5,
115 (1988) (in Japanese).
5) I. Kaneko, K. Eguchi-Kasai, T. Kosaka, T.
Nakano, K. Maruhashi, and T. Takahashi:"DN A Lesion and Cell Death by aParticles and Nitrogen Ions," COS PAR-Molecular and Cellular Effects of Heavy
Ions, 27, 56 (1988).
6) S. Ambe, T. Okada, F. Ambe, I. Tanaka, S.
Nasu, and F.E. Fujita: "In and Ex Situ
Emission Mossbaur Spectra of N 0Carrier-Added 11 9 Sb Electrodeposited onGold," ]. Electrochem. Soc., 135, 949 (1988).
7) K. Maeda, Y. Sasa, M. Maeda, H.
Yusuyama, and M. Uda: "Applecation of
PIXE to Biological Materials in Daily
Life," Proc. 12th Int. Symp. Hosei Univ., p.
453 (1988).
8) H. Kusuyama, K. Okada, T. Kawai, K.
Maeda, Y. Sasa, and M. Uda: "Trace
Elemental Analysis of Renal Cell Carcinoma Using Particle Induced X-Ray
Emission (PIXE)," Trace Met. Metab., Its
Abnorm. Treat., 16, 51 (1988).
9) K. Kimura, T. Kataoka, T. Azuma, Y.
Aoki, Y. Ito, and Y. Tabata: "New Emission Bands at High Density Excitation ofDense Gas and Liquid of Helium Irradiat-313

ed by N -Ions," Phys. Lett. A, 133, 91 (1988).

Osaka, Nov. (1988).
12) T. Kikuchi, K. Morimoto, N. Ohsako, K.
Ikegami, S. Nakajima, and S.H. Be: "NewCryopumps for a Resonator of the RIKEN
Ring Cyclotron," 29th Vacuum Symp.
Proc., Osaka, Nov. (1988).
13) S. Yokouchi, Y. Morimoto, H. Sakamoto,and S.H. Be: "Pumping Characteristics of
NEG Strip," 29th Vacuum Symp. Proc.,
Osaka, Nov. (1988).

(Papers Presented at Meetings)
1. Accelerator development and accelerator
physics
1) H. Sakamoto, Y. Morimoto, S. Yokouchi,
and S.H. Be: "Power Distribution of
Synchrotron Radiation at the 6 GeV Storage Ring," 43th Annu. Meet. Phys. Soc.
Jpn., Kooriyama, Apr. (1988).
2) S.H. Be, Y. Morimoto, H. Sakamoto, andS. Yokouchi: "Conceptual Design of the
Vacuum System for the 6 Ge V Strage
Ring," Advanced Synchrotron Light
Source Conf., N. Y., May (1988).
3) Y. Morimoto, H. Sakamoto, S. Yokouchi,
and S.H. Be: "Conceptual Design andThermal Analysis of the Crotch at the 6
GeV Storage Ring," Advanced Synchrotron Light Source Conf., N. Y., May(1988).
4) T. Fujisawa, K. Ogiwara, S. Kohara, I.
Yokoyama, M. Nagase, Y. Chiba, and Y.
Kumata: "Radio-Frequency System of the
RIKEN Ring Cyclotron," 1st Eur. Paricle
Accelerator Conf., Rome, Jun. (1988).
5) A. Goto: "Injector A VF Cyclotron at
RIKEN," 1st Eur. Particle Accelerator
Conf., Rome, Jun. (1988).
6) Y. Yano: "Status Report on RIKEN Ring
Cyclotron," 1st Eur. Particle Acceletator
Conf., Rome, Jun. (1988).
7) K. Yamasu, H. Miyado, and M. Hara:"The Coceptual Design of the Linac for
the RIKEN -SR," 13th Linear Accelerator
Meet. Jpn., Tsukuba, Sep. (1988).
8) K. Yamasu, H. Miyade, and M. Hara:"The R&D of the 1.5 Ge V Linac for the
RIKEN SR," 13th Linear Accelerator
Meet. J pn., Tsukuba, Sep. (1988).
9) H. Miyade, K. Yamasu, and M. Hara:"The Study of the Positron Injection System for the RIKEN SR," 13th Linear
Accelerator Meet. Jpn., Tsukuba, Sep.
(1988).
10) S.H. Be: "Design of Vacuum Chamber
Components Including Step Changes forthe 6 GeV Storage Ring," Workshop on
Impedance and Current Limitations,
Grenoble, France, Oct. (1988).
11) A. Nishide, S. Yokouchi, M. Iguchi, andS.H. Be: "Effects of Magnetic Fields on
Turbomolecular Pumps for RIKEN Ring
Cyclotron," 29th Vacuum Symp. Proc.,

2.

I

Nuclear physics and nuclear instrumentation
1) T. Minowa, T. Suzuki, C. Yoneyama, H.
Katsuragawa, and M. Shimazu: "Detectionof Laser Cooling Effect by Resonance Ionization Spectroscopy," 43th Annu. Meet.
Phys. Soc. Jpn. Kooriyama, Mar. (1988).
2) H. Katsuragawa, M. Otsuki, K. Nishiyama, Minowa, S. Kawamura, H. Sonobe,
and M. Shimazu: "Resonance Ionization
Spectroscopy of Neutral Atoms Genaratedby Laser Ablation Method," 43th Annu.
Meet. Phys. Soc. J pn. Kooriyama, Mar.
(1988).
3) T. Minowa, H. Katsuragawa, and M.
Shimazu: "Highly Sensitive Detection of
the Laser Cooling Effect of N a Atoms
Using Multiphoton Ionization Method,"1988 Conf. Lasers and Electro-Optics,
Anaheim, Apr. (1988).
4) M. Matsuo, F. Sakata, and Y. Zhuo:"Microscopic Derivation of Transport
Equation in the TDHF Theory," 43th
Annu. Meet. Phys. Soc. Jpn., Kooriyama,
Apr. (1988).
5) K. Ieki, S.M. Lee, M. Ishihara, S. Shirato,
J. Ruan (Gen), T. Motobayashi, H. Murakami, Y. Ando, N. Iwasa, M. Ogiwara, Y.
Nagashima, S.C. Jeong, and H. Fujiwara: .
"Angular Momentum Transfer and Spin
Alignment in the 4°Ar+ 209 Bi Reaction at
26 MeV lu," 43th Annu. Meet. Phys. Soc.
Jpn., Kooriyama, Apr. (1988).
6) T. Motobayashi, K. Ieki, S. Shirato, J.
Ruan (Gen), H. Murakami, Y. Ando, M.
Ogiwara, N. Iwasa, S. Shibuya, J. Kasagi,
H. Hama, K. Yoshida, M. Sakurai, M.
Ishihara, and T. Ichihara: "Nuclear Unbound States Observed in Two Particle
Correlation Measurements," 43th Annu.
Meet. Phys. Soc. Jpn., Kooriyama, Apr.
(1988).
7) K. Asahi, M. Ishihara, T. Ichihara, M.
Fukuda, T. Kubo, Y. Gono, A.C. Mueller,
R. Anne, D. Bazin, D. Guillemaud-Mueller,
R. Bimbot, W.-D. Schmidt-Ott, and J.

314

Kasagi: "Spin Alignment in Projectile
Fragmentation at Intermediate Energies,"
43th Annu. Meet. Phys. Soc. J pn., Kooriyama, Apr. (1988).
8) M. Ishihara, M. Fukuda, K. Asahi, T. Ichihara, T. Kubo, 1. Tanihata, M. Adachi, andM. Koguchi: "Measurement of Total Reaction Cross Section Using Secondary
Beams," 43th Annu. Meet. Phys. Soc. Jpn.,
Kooriyama, Apr. (1988).
9) 1. Tanihata: "Nuclear Studies with
Secondary Radioactive Beams," 3rd Int.
Conf. Nucleus-Nucleus Collisions, SaintMalo, France, Jun. (1988).
10) M. Fukuda, M. Adachi, K. Asahi, T. Ichihara, M. Ishihara, M. Koguchi, T. Kubo,
H. Kumagai, T. Nakagawa, and 1. Tanihata: "Measurement of Interaction Cross
Sections at Intermediate Energies Using
Particle Telescope," 3rd Int. Conf.
Nucleus-Nucleus Collisions, Saint-Malo,
France, Jun. (1988).
11) 1. Tanihata: "Nuclear Structure Studies
with Radioactive Beams," Gordon Research Conf. Nuclear Chemistry ColbySawyer College, New London, New Hampshire, USA, Jun. (1988).
12) K. Asahi, M. Ishihara, T. Ichihara, M.
Fukuda, T. Kubo, Y. Gono, A.C. Mueller,
R. Anne, D. Bazin, D. Gullemaud-Mueller,
R. Bimbot, W.-D. Schmidt-Ott, and J.
Kasagi: "Production of Spin-Aligned Unstable Nuclei in the Projectile Fragmentation at Intermediate Energies," 3rd Int.
Conf. Nucleus-Nucleus Collisions, SaintMalo, France, Jun. (1988).
13) M. Fukuda, M. Adachi, K. Asahi, T. Ichihara, M. Ishihara, M. Koguchi, T. Kubo,
H. Kumagai, T. Nakagawa, and I. Tanihata: "Measurement of Interaction Cross
Section at Intermediate Energies Using
Particle Telescope," 3rd Int. Conf.
Nucleus-Nucleus Collisions, Saint-Malo,
France, Jun. (1988).
14) I. Tanihata: "Radii of Light Neutron-Rich
Nuclei," Int. Symp. Heavy Ion Physics andNuclear Astrophysical Problems, Tokyo,
Jul. (1988).
15) K. Asahi, M. Ishihara, T. Ichihara, M.
Fukuda, T. Kubo, Y. Gono, A.C. Mueller,
R. Anne, D. Bazin, D. Guillemaud-Mueller,
R. Bimbot, W.-D. Schmidt-Ott, and J.
Kasagi: "Spin Alignment in Projectile
Fragmentation at Intermediate Energies,"
Int. Symp. Heavy Ion Reactions andNuclear Astrophysical Problems, Tokyo,

Jul. (1988).
16) M. Koguchi, M. Fukuda, K. Asahi, H.
Kumagai, M. Adachi, I. Tanihata, and M.
Ishihara: "Rotating Catcher System for
Beta Decay Studies of Projectile Fragments," Int. Symp. Heavy Ion Reactions
and Nuclear Astrophysical Problems,Tokyo, Jul. (1988).
17) H. Katsuragawa, T. Minowa, T. Suzuki,
and M. Shimazu: "Isotopic Enrichment
Uing Laser Cooling of Atomic Beam,"
25th Annu. Meet. Radioisotopes in the
Physical Sciences and Industries, Tokyo,
Jul. (1988).
18) S. Yamaji: "Self-Cosistent Trancport
Coefficients for Damped Motion," Lanzhou Int. Summer Sch. Heavy Ion Collisions, Lanzhou, China, Aug. (1988).
19) M. Matsuo, F. Sakata, T. Marumori, andY. Zhuo: "Master Equations in the Microscopic Theory of Nuclear Collective
Dynamics," Lanzhou Int. Summer Sch.
Heavy Ion Reaction Theory, Lanzhou,
China, Aug. (1988).
20) K. Asahi: "Measurement of 9 -Factors for
Nuclei Far from Stability," 1988 Fall
Meet. Phys. Soc. Jpn., Matsuyama, Oct.
(1988).
21) K. Ieki, S.M. Lee, M. Ishihara, S. Shirato,
J. Ruan (Gen), T. Motobayashi, H. Murakami, Y. Ando, N. Iwasa, M. Ogiwara, Y.
Nagashima, S. Okumura, S.C. Jeong, F.
Fujiwara, Y.H. Pu, T. Mizota, and T.
Murayama: "Angular Momentum Tranfer
and Spin Alignment in the 40 Ar + 209Bi
Reaction at 26 MeV l u II," 1988 Fall Meet.
Phys. Soc. lpn., Matsuyama, Oct. (1988).
22) T. Nakagawa, W. Bohne, H. Morgenstern,
K. Grabisch, and S. Proschitzki: "Maximum Excitation Energy of Compound
Nucleus," 1988 Fall Meet. Phys. Soc. lpn.,
Matsuyama, Oct. (1988).
23) M. Oshima, S. Ichikawa, H. Iimura, E.
Minehara, H. Kusakari, T. Inmaura, A.
Hashizume, and M. Sugawara: "Groundstate Rotational Bands in 157Gd and 173Yb,"
1988 Fall Meet. Phys. Soc. Jpn., Matsuyama, Oct. (1988).
24) K. Sueki, H. Nakahara, and I. Kohno:"Nuclear Charge Distribution in Deep Inelastic Scattering Process on Heavy Ion
Reaction between Light Mass Nuclei,"1988 Fall Meet. Phys. Soc. 1pn., Matsuyama, Oct. (1988).
25) M. Otsuki, T. Minowa, H. N akahama, H.
Katsuragawa, and T. Inamura: "Reso-315

nance Ionizaiton Spectroscopy Using
Laser Ablation-Thermal Aromic Beam,"
1988 Fall Meet. Phys. Soc. Jpn., Hiroshima, Oct. (1988).
26) T. Suzuki, T. Minowa, H. Horibe, and H.
Katsuragawa: "Detection of Laser Cooling
Effect by Resonance Ionization Spectroscopy II," 1988 Fall Meet. Phys. Soc. Jpn.,
Hiroshima, Oct. (1988).
27) T. Suzuki, I. Tanihata, T. Kubo, T. Ichihara, T. Kobayashi, and M. Fujiwara:"Subthreshold Pion Production in Heavy~
Ion Collisions," 43th Annu. Meet. Jpn.
Phys. Soc. Kooriyama, Oct. (1988).
28) I. Tanihata, W.P. Liu, T. Kubo, T. Suzuki,
M. Yanokura, T. Doke, Y. Yamaguchi, T.
Murakami, T. Yanagimachi, and N.
Hasebe: "Test Experiment for New Isotope Search at RRC," 43th Annu. Meet.
Jpn. Phys. Soc., Kooriyama, Oct. (1988).
29) M. Ishihara, K. Asahi, T. Ichihara, T.
Kubo, 1. Tanihata, M. Fukuda, M. Adachi,
and M. Takada: "Interaction Cross Section Measurement Using SecondaryRadioisotope Beams," 43th Annu. Meet.
Jpn. Phys. Soc., Kooriyama, Oct. (1988).
30) T. Kobayashi, 1. Tanihata, T. Shimoura,
K. Matsuta, Y. Miyatake, K. Sugimoto, H.
Wieman, D. Olson, W. MUller, and J.
Symons: "Target Mass Dependence ofTotal Interaction Cross Sections for Dripline Nuclear," 43th Annu. Meet. Jpn. Phys.
Soc., Kooriyama, Oct. (1988).
31) M. Matsuo: "Microscopic Approach to
Nuclear Collective Dynamics in Highly
Excited Region," INS Symp. Vibration
and Rotation in Nuclei, Tokyo, Nov.
(1988).
32) M. Matsuo: "Microscopic Approach toDissipative Large Amplitude Collective
Motions," RIFP Symp. Non-Linear
Dynamics in Nuclear Collective Motions,
Kyoto, Dec. (1988).
33) T. Inamura: Laser Nuclear Spectroscopy,"
Symp. Laser Sciences, Wako, Dec. (1988).
3. Atomic and solid-state physics
1) A. Koyama: "Characteristics of Metal
Electron Excitation by Fast High Charge
Ions," RIKEN Symp., Wako, Mar. (1988).
2) H. Ishikawa, Y. Sasa, and A. Koyama:"Energy Spectrum of AI- LVV Auger Electrons Induced by Grazing Angle Incident
Fast Heavy Ion Impact," RIKEN Symp.,
Wako, Mar. (1988).
3) A. Koyama: "Characteristics of Metal

Electron Excitation by Fast High Charge
Ions," RIKEN Symp., Wako, Mar. (1988).
4) H. Ishikawa, Y. Sasa, and A. Koyama:"Energy Spectrum of AI-L VV Auger Electrons Induced by Grazing Angle Incident
Fast Heavy Ion Impact," RIKEN Symp.,
Wako, Mar. (1988).
5) Aono Keiko, Iwaki Masaya, and N amba
Susumu: "Ion Implantation in CaF 2 (III),"
19th Symp. Ion Implantation and Submicron Fabrication (RIKEN Symp.),
Wako, Mar. (1988).
6) Y. Awaya, T. Mizogawa, Y. Kanai, H.
Kumagai, M. Kase, and K. Shima:"Charge-State Distribution of Fast Heavy
Ions after Passing through Solid Targets,"
Symp. Interactions between Ion Beam andSolids, Tokyo, Mar. (1988).
7) E. Vagi: "Lattice Location Study on
Hydrogen in Metals by Means Ion Beam
Analysis," Symp. Ion Beam Interactions
with Solids, Tokyo, Mar. (1988).
8) K. Ishida, T. Matsuzaki, and K.
N agamine: "Radiative Transition in Muon
Transfer Reaction," Atomic Physics
Forum, Nagoya, Mar. (1988).
9) Y. Sakamoto, K. Yano, H. Oyama, and S.
!toh: "Erosion of MoS 2 by Irradiation of
Hydrogen Plasma I," 1988 Spring Meet.
J pn. Soc. Plasma Science and Nuclear
Fusion Research, Tsukuba, Mar. (1988).
10) H. Tawara: "Production Processes ofHighly Charged Ions," 43th Annu. Meet.
Phys. Soc. Jpn., Kooriyama, Mar. (1988).
11) H. Mitsuya, K. Nakamura, 1. Hashimoto,H. Yamaguchi, E. Vagi, and M. Iwaki:"Motion of Kr Bubbles in Kr-Implanted
Aluminum," 43th Annu. Meet. Phys. Soc.
Jpn., Kooriyama, Apr. (1988).
12) E. Vagi, T. Kobayashi, S. Nakamura, F.
Kano, K. Watanabe, Y. Fukai, and T.
Matsumoto: "Trapping of Hydrogen in
Nb-Mo Alloys," 43th Annu. Meet. Phys.
Soc. Jpn., Kooriyama, Apr. (1988).
13) K. Ishida, T. Matsuzaki, and K.
N agamine: "Design of a Superconducting
Secondary Beam Course with Large
Acceptance Using Axi-Symmetric Magnetic Field," 43th Annu. Meet. Phys. Soc.
Jpn., Kooriyama, Mar. (1988).
14) T. Watanabe: "Theoretical Aspects ofElectron Capture by C6+ and 0 8 + from H,
H 2 , and He," IAEA Specialists' Meet.
Carbon and Oxygen Collision Data for
Fusion Plasma Research, Vienna, May(1988).

316

15) Y. Sakamoto, K. Yano, H. Oyama, H.
Kokai, A. Itoh, and A. Miyahara: "Deterioration of Molybdenum (MoS 2 ) by Hydrogen Plasma Irradiation," 8th Int. Conf.
Plasma-Surface Interactions in Controlled
Fusion Devices, JUlich, May (1988).
16) E. Vagi: "Lattice Location Study on Kr
Atoms in Aluminium by Means of the
Channelling Method," 6th Int. Conf. Ion
Beam Modification of Materials, Tokyo,
Jun. (1988).
17) T. Fujihana, Y. Okabe, and M. Iwaki:"Effects of Implantation Temperature on
The Hardness of Iron Nitrides Formed
with High Nitrogen Dose," 6th Int. Conf.
Ion Beam Modification of Materials,
Tokyo, Jun. (1988).
18) 1. Kohno: "Production of Fast Switching
Power Thyristor by Proton Irradiation,"
7th Int. Conf. Ion Implantation Technology, Kyoto, Jun. (1988).
19) K. Kobayashi: "Effect of Incident Angles
of N -Implantation on Recrystallization of
AIN x Thin Films, 7th Int. Conf. Ion Implantation Technology, Kyoto, Jun. (1988).
20) T. Watanabe: "Theories of Electron Capture by lon-Atom Collisions," Semin.
Atomic Physics Group in A TOMKI, Inst.
Nucl. Res. Hung. Acad. Sci., Debrecen, 'Hungary, Jun. (1988).
21) T. Watanabe: "Radiative Processes Induced by lon-Atom Collisions," Semin.
Atomic Physics Group in A TOMKI, Inst.
N ucl. Res. Hung. Acad. Sci., Debrecen,
Hungary, Jun. (1988).
22) S. Karashima, K. Hino, and T. Watanabe:"Equilibrium Charge States of Relativistic
Uranium Projectile Ions in Matter," lIth
Int. Conf. Atomic Physics, Paris, J ul.
(1988).
23) K. Hino, and T. Watanabe: "Photon Angular Distribution of the Ultra-Relativistic
K-Shell Radiative Electron Capture by
Heavy Ion Collisions," lith Int. Conf.
Atomic Physics, P.aris, Jul. (1988).
24) K. Hino, and T. Watanabe: "Angular
Distribution and Linear-Polarization of X
Rays Induced by Radiative Electron Capture," lith Int. Conf. Atomic Physics,
Paris, J ul. (1988).
25) Y. Awaya, K. Hino, Y. Kanai, A. Hitachi,
H. Vogt, K. Kuroki, and Y. Yamazaki:"Momentum Distribution of Be 2s Electrons Measured by Radiative Electron
Capture in Heavy Ion Collisions," lith Int.
Conf. Atomic Physics, Paris, Jul. (1988).

26) T. Mizogawa, Y. Awaya, T. Kambara, Y.
Kanai, M. Kase, H. Kumagai, and K.
Shima: "Charge-Equilibration Processesof 50-MeV Ar Ions Passing through Solid(C Foils) and Gaseous (CH 4 ) Targets," lithInt. Conf. Atomic Physics, Paris, J ul.
(1988).
27) T. Fujimoto and 1. Shimamura: "Electronic States in High Density Plasma andCharge Equilibrium," 13th, Res. Meet. Soc.
Atomic Collision Research, Tokyo, Jul.
(1988).
28) T. Kambara: "Experiments of RTE in
GSI," 13th Res. Meet. Soc. Atomic Collision Research, Tokyo, Jul. (1988).
29) E. Vagi: "Study on a State of Hydrogen in
Metals by the Channelling Method,"
Symp. Tandem Accelerator and · Related
Technique, Tokyo, Jul. (1988).
30) T. Watanabe: "The Report of the Visit toFrance," Jt. Semin. on "Radiative andCollisional Process in High Density
Plasma" and on "Elementary Theory for
Diagnosis of High Density Plasma,"
Nogoya Univ., Jul. (1988).
31) Y. Awaya, T. Kambara Y. Kanai, T.
Mizogawa, A. Hitachi, and B. Sulik: "Systematics of Multiple Inner-Shell Ionizationof Target Atoms by 0.8-26 MeV l u Heavy
Ion Impact," Spectroscopy and Collisionsof Few Electron Ions, Bucharest, Aug.
(1988).
32) E. Vagi, S. Nakamura, F. Kano, T.
Kobayashi, K. Watanabe, Y. Fukai, and T.
Matsumoto: "Hydrogen Trapping by
Solute Atoms in Nb-Mo Alloys as Observed by the Channelling Method," Int. Symp.
Metal- Hydrogen Systems-Fundamentals
and Applicaitions, Stuttgart, Sep. (1988).
33) E. Vagi, S. Nakamura, F. Kano, T.
Kobayashi, K. Watanabe, Y. Fukai, and T.
Matsumoto: "Hydrogen Trapping by
Solute Atoms in Nb-Mo Alloys as Observed by the Channeling Method," 3rd SinoJpn. Symp. Metal Physics and Physical
Metallurgy, Shanghai, Sep. (1988).
34) E. Vagi, H. Sakairi, A. Koyama, and R.R.
Hasiguti: "Recovery and Reverse Annealing of Priton- or a-Particle-Irradiated
CU3Au at Low Temperatures," 3rd SinoJ pn. Symp. Metal Physics and Physical
Metallurgy, Shanghai, Sep. (1988).
35) 1. Shimamura: "Rydberg Serfes of Doubly
Excited Resonance States of H 2 , " Okazaki
Conf. Theoretical Chemistry of Excited
Molecules, Okazaki, Sep. (1988).

31736) Y. Awaya, T. Kambara, and T. Kanai:"Experimental Studies of Heavy lon-Atom
Collisions at RIKEN Ring Cyclotoron,"Int. Semin. Atomic and Molecular Physics-2nd Chin.-Jpn. Jt. Semin., Fuji-Yoshida,
Oct. (1988).
37) I. Shimamura: "Doubly Excited Rydberg
Series of Molecular Repulsive States: Hz,"
Int. Semin. Atomic and Molecular Physics-2nd Chin.-Jpn. Jt. Semin., Fuji-Yoshida,
Oct. (1988).
38) T. Watanabe: "Rearrangement Processesof Coulomb Interacting Three-Body Systems," Int. Semin. Atomic and Molecular
Physics- 2nd Chin.-Jpn. Jt. Semin., FujiYoshida, Oct. (1988).
39) T. Tonuma, T. Mukoyama, T. Koizumi, T.
Matsuo, H. Shibata, K. Shima, H. Tawara,
and A. Yagishita: "Multiple-Photoionization of Xe in the Vicinity of L Edges," Int.
Semin. Atomic and Molecular Physics- 2nd Chin.-Jpn. Jt. Semin., Fuji-Yoshida,
Oct. (1988).
40) H. Tawara, T. Tonuma, H. Kumagai, andT. Matsuo: Charge Distributions of Recoil
Ions Accompanied with Multiple Ionization of Heavy Projectile Ions: 1.05 Me V /amu Ne q+ and Ar q+ + Ne and Ar Collisions," Int. Semin. Atomic and Molecular
Physics- 2nd Chin.-Jpn. Jt. Semin., FujiYoshida, Oct. (1988).
41) T. Tonuma, T. Mukoyama, T. Koizumi,
T. Mastsuo, H. Shibata, K. Shima, H.
Tawara, and A. Yagishita: "MultiplePhotoionization of Xe in the Vicinity of L
Edges," Int. Semin. Atomic and Molecular
Physics-2nd Chin.-Jpn. Jt. Semin., FujiYoshida, Oct. (1988).
42) H. Tawara, T. Tonuma, H. Kumagai, andT. Matsuo: Charge Distributions of Recoil
Ions Accompanied with Multiple Ionization of Heavy Projectile Ions: 1.05 MeV /amu Ne q+ and Ar q+ + Ne and Ar Collisions," Int. Semin. Atomic and Molecular
Physics-2nd Chin.-Jpn. ]t. Semin., FujiYoshida, Oct. (1988).
43) A. Keiko, I. Masaya, and N. Susumu:"Luminescence during Ion-Implantation
into CaF z (111)," 1988 Fall Meet. J pn. Soc.
Appl. Phys., Toyama, Oct. (1988).
44) K. Tanaka, T. Takahari, K. Kawakami,
and E. Yagi: "Characterization of Crystallinity of Thin Ge Layer Epitaxially Grown
on Si," 1988 Fall Meet. Jpn. Soc. Appl.
Phys., Toyama, Oct. (1988).
45) A. Koyama: "Secondary Electron Emis-sion from Metals Induced by Fast Ion
Impact," Physikkolloq. J ohanes Kepler
Univ., Linz, Oct. (1988).
46) H. Tawara: "Production of Highly
Charged Ions in Particle and Photon
Impact," Meet. "Research of Multiply
Charged Ion Science," Takehara, Oct.
(1988).
47) H. Maeda, A. Suzuki, Y. Mizugai, Y.
Matsumoto, and M. Takami: "Resonancelonazation Spectroscopy of Heavy Metal
Elements," Fall Meet. Atomic Energy
Meet., Kobe, Oct. (1988).
48) A. Koyama, H. Ishikawa, and Y. Sasa:"Energy Spectra of AI-L VV Auger Electrons Induced by Grazing Angle Incident
Fast Heavy Ion Impact," 1988 Fall Meet.
Phys. Soc. Jpn., Hiroshima, Oct. (1988).
49) A. Koyama, H. Ishikawa, and Y. Sasa:"Excitation of Convoy-Like Electrons by
Glancing Angle Incident Heavy High
Charge Ions," 1988 Fall Meet. Phys. Soc.
Jpn., Hiroshima, Oct. (1988).
50) A. Koyama, H. Ishikawa, and Y. Sasa:"Energy Spectra of AI- LVV Auger Electrons Induced by Grazing Angle Incident
Fast Heavy Ion Impact," 1988 Fall Meet.
Phys. Soc. Jpn., Hiroshima, Oct. (1988).
51) I. Shimamura, C.J. Noble, and P.G. Burke:"Doubly Excited Resonant Rydberg Seriesin Hydrogen Molecules," 1988 Fall Meet.
Phys. Soc. Jpn., Hiroshima, Oct. (1988).
52) E. Yagi: "Behaviour of Kr Atoms Implanted into AI," 1988 Fall Meet. Phys. Soc.
Jpn., Hiroshima, Oct. (1988).
53) M. Koizumi, T. Horiguchi, M. Wakasugi,
H. Sakata, and Y. Yoshizawa: "Rotational
Quantum-Number Dependence of Hyperfine Spritting in 1z7I z," 1988 Fall Meet.
Phys. Soc. J pn., Hiroshima, Oct. (1988).
54) Y. Mizugami, H. Maeda, Y. Matsumoto,
A. Suzuki, and M. Takami: "Resonance
Ionization Spectriscopy of Lantanoid Elements," 1988 Fall Meet. Phys. Soc. Jpn.,
Hiroshima, Oct. (1988).
55) T. Watanabe, and L. Vegh: "Dynamic
Electron Correlation in Charged-Particle
Collision and Photoionization," 1st AsianPac. Conf. Atomic and Molecular Physics,
Taipei, Nov. (1988).
56) T. Watanabe, K. Hino, Y. Awaya, T.
Kambara, and Y. Kanai: "Studies of
Heavy Ion-Atom Collisions at RIKEN
Ring Cyclotron," 1st Asian-Pac. Conf.
Atomic and Molecular Physics, Taipei,
Nov. (1988).

31857) Y. Awaya, T. Kambara, and Y. Kanai:"Experimental Studies of Heavy Ion-Atom
Collisions at RIKEN Ring Cyclotron," 1stAsian-Pac. Conf. Atomic and Molecular
Physics, Taipei, Nov. (1988).
58) K. Ando, S. Kohmoto, Y. Awaya, T.
Tonuma, and S. Tsurubuchi: "Analysis of
Mg IX 2s3d-2s4f Transition of Beam-Foil
Spectra," 1st Asian-Pac. Conf. Atomic andMolecular Physics, Taipei, Nov. (1988).
59) T. Watanabe and L. Vegh: "Scattering
Correlation in Multiple Ionization by Proton, Anti-Proton and Multi-Charged Ion
Impact," 10th Conf. Application of Accelerators in Research and Industry, Denton,
Nov. (1988).
60) K. Hino and T. Watanabe: "Intensities andAngular Distribution of X-Rays by
Radiative Electron Capture in UltraRelativistic Ion-Atom Collisions," 10th
Conf. Application of Accelerators in
Research and Industry, Denton, Nov.
(1988).
61) T. Watanabe: "Experimental and Theoretical Studies of Radiative Electron Capture
in Ion-Atom Collisions," 4th Int. Workshop
Cross Sections of Fusion and Other Applications, College Station, Nov. (1988).
62) T. Fujihana, Y. Okabe, and M. Iwaki:"The Relationship between Crystal Structure and Hardness of Nitrogen Implanted
Iron Surface Layers," Fall Meet. Materials Research Soc., Boston, USA, Nov.
(1988).
63) T. Tawara, T. Tonuma, T. Matsuo, A.
Yagishita, H. Shibata, T. Koizumi, K.
Shima, and T. Mukoyama: "Multiply
Photoionization of Rare Gas Atoms Resulting in Production of Multiply Charged
Ions," Kansas Univ. Semin., Nov., Manhattan, Kansas (1988).
64) K. Yano, Y. Sakamoto, H. Oyama, H.
Kokai, S. Hoh, T. Banno, and S. Baba:"Erosion of MoS 2 by Irradiation of Hydrogen Plasma II," 3rd Symp. Plasma Scienceand Nuclear Fusion Research and RelatedSocieties, Tokyo, Nov. (1988).
65) Y. Kanai, T. Kambara, and Y. Awaya:"Beam Line for Atomic Physics andResults of Test Experiments," RIKEN
Symp. Studies of Solid State Physics andMaterials, Atomic Processes, Nuclear
Chemistry, and Biology and Medical Science by Using Ring Cyclotron, Wako, Dec.
(1988).
66) K. Ishida, T. Matsuzaki, and K. Nagamine:"Test Experiments at the Solid State
Physics and Materials Beam Course,"
RIKEN Symp. Studies of Solid State
Physics and Materials, Atomic Processes,
Nuclear Chemistry, and Biology and Medical Science by Using Ring Cyclotron,
Wako, Dec. (1988).
67) H. Maeda, Y. Mizugai, Y. Matsumoto, A.
Suzuki, and M. Takami: "Multistep andMultiphoton Resonance Ionization Spectroscopy of Lantanoids," RIKEN Symp.
Laser Science, Wako, Dec. (1988).
68) H. Maeda: "Resonance Ionization Spectroscopy of Lantanoid Elements," RIKEN
Symp. Laser Nuclear Spectroscopy,
Wako, Dec. (1988).
69) I. Shimamura: "Application of the RMatrix Method to Doubly Excited Molecular States," 7th Indian N atl. Workshop
and Conf. Atomic and Molecular Physics,
Aligarh, India, Dec. (1988).
70) I. Shimamura: "Theory of ElectronMolecule Collisions," Symp. Atomic, Collisions, Kalyani, India, Dec. (1988).
4.

Radiochemistry, radiation chemistry, andradiation biology
1) T. Takahashi and S. Nagaoka: "Radiation
Environment in Space," Symp. Manned
Space Flight, Tokyo, Jan. (1988).
2) T. Takahashi, M. Uehara, E. Watanabe,
T. Katayama, K. Nakano, T. Kusaya, I.
Kaneko, and F. Yatagai: "Plastic Track
Detector for the Investigation of Inactivation of Bacterial Spores by a Single Heavy
Ion," 35th Spring Meet. Jpn. Soc. Appl.
Phys. and Related Societies, Tokyo, Mar.
(1988).
3) T. Doke and T. Takahashi: "Dosimetry
and Biological Experiments in Space Environment," 35th Spring Meet. J pn. Soc.
Appl. Phys. and Related Societies, Tokyo,
Mar. (1988).
4) T. Takahashi, F. Yatagai, T. Katayama,
T. Kasuya, and T. Doke: "Improvement in
the Position Accuracy and Viability for
the Inactivation of B. subtilis Spores by aSingle Heavy Ion," 6th Track Detector
Symp., Tokyo, Apr. (1988).
5) I. Kaneko, K. Eguchi-Kasai, T. Kosaka,and K. Nakano: "Effects of Charged Particle Beam on DNA in Human Melanoma
Cells," Int. Conf. Large Dose Ionizing andN on-Ionizing Radiation, Hanzo, China,
Apr. (1988).
6) K. Kimura: "Electronic Excitation by

319

Heavy Ions," Ann. Meet. Chern. Soc. Jpn.,
Tokyo, Apr. (1988).
7) K. Kimura: "Roles of Rydberg Transitions
to Ionization Potential, Electron Mobility,
and Rate of Excitation Transfer in Condensed Matter," 5th Semin. Radiat. Chern.
Jpn., Wako, May (1988).
8) 1. Kaneko, K. Eguchi-Kasai, T. Kosaka, K.
Nakano, A. Maruhashi, and T. Takahashi:
DNA Lesion and Cell Desth by a-Particles
and Nitrogen Ions," COSPAR 27th Plenary Meet., Helsinki, Jul. (1988).
9) H. Sunaga, T. Agematsu, R. Tanaka, T.
Sasaki, K. Yoshida, and I. Kohno: "ThinCellulose-Triacetate Film Dosimeter,"25th Annu. Meet. Radioisotopes in the
Physical Sciences and Industries, Tokyo,
Jul. (1988).
10) 1. Kaneko, K. Eguchi-Kasai, T. Kosaka, K.
Nakano, A. Maruhashi, and T. Takahashi:"DNA Lesion and Cell Death by aParticles and Nitrogern Ions," 27th Plenary Meet. Committee on Space Research,Helsinki, Finland, Jul. (1988).
11) T. Kosaka, K. Eguchi-Kasai, and 1. Kaneko: "DNA Damages Induced by Heavy
Ions and Its Repair," RIKEN Symp., Yokohama, Aug. (1988).
12) K. Suzuki, M. Watanabe, M. Suzuki, and 1.
Kaneko: "Lethal and Neoplastic Transforming Effects of High LET Radiations,"
RIKEN Symp., Yokohama, Aug. (1988).
13) K. Maeda, Y. Sasa, K. Yoshida, H.
Kusuyama, and M. Uda: "Multielemental
Analysis of Human Spermatozoa andSeminal Plasma Using Particle Induced
X-Ray Emission (PIXE) Spectroscopy,"
57th Natl. Meet. Chern. Soc. Jpn., Sendai,
Sep. (1988).
14) Y. Sasa, K. Maeda, T. Kitamura, and M.
Uda: "Application of PIXE to Materials
Science, (1) Analysis of Thin Al Foils,"
57th Natl. Meet. Chern. Soc. Jpn. , Sendai,
Sep. (1988).
15) 1. Kaneko, M. Watanabe, M. Suzuki, andK. Suzuki: "Transformation Effect of aParticles and Nitrogen Ions," 14th L.H.
Fray Conf.-Low Dose Radiation-Biological Bases of Risk Assessment, Oxford,
Sep. (1988).
16) 1. Kaneko, K. Eguchi-Kasai, T. Kosaka,and K. Sato: "A Comparison of DNA
Double Strand Breaks Among Four Different Radiation-Sensitive Mammalian
Cells," 47th Annu.Meet. Jpn. Cancer Soc.,
Tokyo, Sep. (1988).

17) Y. Itoh, K. Kadota, H. Fukushima, N.
N onaka, and K. Tachi: "Study on Carbon,
Boron and Oxygen in LEC-GaAs," 49th
Fall Meet. Jpn. Soc. Appl. Phys., Toyama,
Oct. (1988).
18) M. Tachibana, T. Mukouyama, H. Adachi,
K. Fuwa, Y. Sasa, and M. Uda: "Analysis
of F K Satellite Spectra," '88 Fall Meet.
Phys. Soc. Jpn., Hiroshima, Oct. (1988).
19) M. Suzuki, K. Suzuki, M. Watanabe, and I.
Kaneko: "Celular Transformation Transformation by Heavy Ions," 31st Annu.
Meet. Jpn. Radiation Research Soc., Hiroshima, Oct. (1988).
20) T. Takahashi, F. Yatagai, T. Katayama,
N. Imarnura, and 1. Nozaki: "Interpretation of Inactivation Cross of E. coli K-12
Series," 31th Annu. Meet. Jpn. Radation
Research Soc., Hiroshima, Oct. (1988).
21) K. Kimura, T. Suzuki, K. Uehara, and K.
Watanabe: "Decay Measurement of Fast
Emission of BaF 2 Single Crystal Excitedby Heavy Ions," Fall Meet. Phys. Soc. Jpn.,
Hiroshima, Oct. (1988).
22) K. Nakagawa, K. Kimura, A. Ejiri, and M.
Nishikawa: "Photoionization Process of
Anthracene in Super Critical State of Xe:
Roles of Rydberg States," Fall Meet. Phys.
Soc. Jpn., Hiroshima, Oct. (1988).
23) K. Nakagawa, A. Ejiri, M. Nishikawa, andK. Kimura: "Solvation Effect of Super
Critical Xe on Rydberg States and on
Photoionization of Anthracene," Meet.
Mol. Struc., Tokyo, Oct. (1988).
24) M. Watanabe, M. Suzuki, K. Suzuki, 1.
Kaneko, and K. Nakano: "Neoplastic
Transformation of Cultured Mammalian
Cells by Cosmic Rays," 2nd Annu. Meet.
J pn. Soc. Biological Sciences in Space,Tokyo, Nov. (1988).
25) 1. Kaneko, K. Eguchi-Kasai, T. Kosaka, G.
Okada, and K. Nakano: "Effects of Heavy
Ions on DNA in Mammalian Cells," 2ndAnnu. Meet. J pn. Soc. Biological Sciencesin Space, Tokyo, Nov. (1988).
26) H. Kusuyama, K. Okada, K. Yoshida, K.
Maeda, Y. Sasa, and M. Uda: "Trace
Element Analysis of Human Spermatozoa
and Seminal Plasma," 33rd Annu. Meet.
Infecundity Sod. Jpn., Kyoto, Nov. (1988).
27) K. Kimura, K. Uehara, T. Suzuki, and K.
Watanabe: "Measurement Technique ofFast Emission Decay by Heavy Ion Excitation," 31th Meet. Radiat. Chern. Jpn.,
Tokyo, Nov. (1988).
28) K. Kimura: "Phenomena of Ionization and320

Excitation at High Density by Heavy Ion
Irradiation," 2th Workshop Application ofRadiation, Tokyo, Nov. (1988).
29) T. Takahashi, F. Yatagai, T. Kosaka, K.
Nakano, and T. Kanai: "Dosimetry at
RRC Biology Facility," RIKEN Symp.
Studies on Materials Scienses, Atomic
Processes, Nuclear Chemistry, and Radiobiology by RIKEN Ring Cyclotron, Wako,
Dec. (1988).
30) M. Suzuki, I. Kaneko, S. Yamashita, and S.
Hashimoto: "The Combined Effects of
Cis-Dichlorodiammineplatinum and Heavy
Ions," RIKEN Symp., Vvako, Dec. (1988).
31) M. Watanabe, K. Suzuki, M. Suzuki, and I.
Kaneko: "Neoplastic Transformation by

Heavy Ions," RIKEN Symp., Wako, Dec.
(1988).
32) I. Kaneko, G. Okada, and H. Mitsui:"Mutation-Modifying Effects of Nicotin
Nicotinamide and Inhibitors of Poly
(ADP-ribose) Polymerase in Mammalian
Cells," 3rd Int. Conf. Mechanisms of
Antimutagenesis and Anticarcinogesis,
Ohito, Dec. (1988).
33) K. Tachi, M. Aratani, T. Kato, M. Yanokura, T. Sato, M. Otsuka, and M. Tsujiguchi: "Light Element Depth Profiling by
RILAC Applied to the Study on the Composition of Anodic Oxide Films on Titanium," 7th Symp. Ion Beam Technology,
Tokyo, Dec. (1988).

321

VIII.

LIST OF OUTSIDE USERS AND THEIR THEMES(Jan.-Dec. 1988)
1) N. Nonaka"Radiochemical Analysis of 16 0, 14N,
and 12C in Si Crystal and GaAs"

Japan Chemical Analysis Center2) S. Hokuyo"Radiation Damage of GaAs Solar
Cells"

Mitsubishi Electric Co., Ltd.

3) H. Okazaki"Radiation Damage of InP Solar Cells"

Nippon Mining Co., Ltd.

4) T.Ohga

Nippon Telephone Telegram Co., Ltd.

"Radiation Damage of Solar Cells"
5)

K. Tomii"Improvement of Thyristors by Proton
Irradiation"6) H. Akiyama

Semiconductor R&D Lab., Matsushita ElectricWork Co., Ltd.

LSI Lab., Mitusbishi Electric Co., Ltd.

"Improvement of Thyristors by Proton
Irradiation"7) M. Kitagawa

Toshiba Co., Ltd.

"Improvement of Thyristors by Proton
Irradiation"8) Y. Shimizu"Improvement of Thyristors by Proton
Irradiation"

Hitachi Co., Ltd.

9) A. Morio"Study of Single Event Upset in Microprocessors by Bombarding 14N Particles"

Japan Trust Center for Electronic Parts

10) K.Ogura"Test of Sensibility of CR39 Track
Detector for High Energy Protons"

Faculty of Engineering, Nippon University11) H. Arai
"Radiation Damage of Solar Cells"

NEC Co., Ltd.

322

IX.

LIST OF SEMINARS(Jan.-Dec. 1988)"Recent Result from AGS Heavy Ion
Experiment"

1) T. Tachibana, Waseda Univ. (Tokyo), 27
January"New Mass Formula and Improved Gross
Theory of f3 Decay"12) K. Kuroda, LAPP (France), 2 August"Development of Position Sensitive
Photo-M ul tiplier"2) S. Kinouchi, Tsukuba Univ. (Ibaraki), 10
February"Cranking Term Arising from VelocityDependent Potential and Comments on
Super-Deformed Band"13) T. Murakami, Michigan State Univ. (USA),
3 August"Can We Measure the Temperature fromthe Population of Particle UnboundStates ?"3) T. Kajino, Tokyo Metropolitan Univ.
(Tokyo), 15 April"Big Bang Nucleosynthesis and the Roleof Unstable Nuclei"14) R.H. Siemssen, KVI (Netherlands), 3 August"Probing the Dynamics of Asymmetric
Heavy-Ion Reactions with the K X-Ray
Method"4) S. Matsui, Hiroshima Univ. (Hiroshima), 27
April"Precise Measurement of 177mLu y Rays by
Means of Pulser"

15) C.Y. Wong, Oakridge Natl. Lab. (USA), 30
August"Anomalous Positron Peaks in Heavy Ion
Collisions"5) S. Tasaka, Gifu Univ. (Gifu), 25 May"Calibration of CR-39 Solid-State Detector
by Means of RRC Beam"

16) S. Yoshida, Yamagata Univ. (Yamagata), 20
September"Pre-Equilibri urn Processes"

6) S.S. Kapoor, Bhabha Atomic Research Center (India), 31 May"Heavy-Ion Induced Fission and FissionLike Reaction"17) N. Tajima, Univ. Tokyo (Tokyo), 11 October"K-Isomerism and y-Softness"

7) H. Shengnian, Inst. Atomic Energy (China), 4
June"N eutron Induced Fission and Spontaneous Fission"18) J. Alstad, Univ. Oslo (Norway), 11 N ovember"New Development in the SISAK-Techniques for Studying Short Lived Nuclei-"

8) S. !ida, Inst. Nuclear Study (Tokyo), 7 June
"Berry Phase"

19) K. Kimura, Kyushu Univ. (Fukuoka), 16
November"An Approach to Heavy Ion Particle Identification in Terms of Gas Counter"

9) D.H. Feng, Drexel Univ. (USA), 16 June
"Dynamical Pauli Effect, Saturation of
Nuclear Collectivity a and the Fermion
Dynamical Symmetry Model"

20) H. Wollnik, Univ. Giessen (West Germany),
21 November"Mass Separation of Short-Lived Nuclei
by Recoil- and Ion-Source Separators"

10) Z. Yizhong, Inst. Atomic Energy (China), 22
June"Recent Progress in Fission Theory Basedon Diffusion Model"

21) B. Heush, C.R.N. Strasbourg (France), 7
December"Study of Peripheral Collision for the
4°Ar+ 27 Ag, natTi at 44 MeV In and 4°Ar+
natAg at 30 and 60 MeV In by Inclusive andExclusive Measurements at GANIL"

11) Y. Miake, Brookheaven Natl. Lab. (USA), 29
July22) S. Kinouchi, Inst. Nuclear Study (Tokyo), 13

323

December"Effect of Velocity-Dependent Terms in
Super-Deformed Nuclei"23) Y. Yamamoto, Tsukuba Univ. (Ibaraki), 13
December"Quantum Theory of the Selfconsistent
Collective Coordinate Method and Stability Problem"24) T. Muto, Kyoto Univ. (Kyoto), 13 December"Pion Condensation in High Density
Nuclear Matter and Neutron Star
Phenomena"25) K. Saotome, Tohoku Univ. (Miyagi), 13
December"Finite Temperature Nuclear Matter in
TFD Formalism"

324

x.

LIST OF PERSONNEL

Members of the Board
AMBE Fumitoshi 3i: fm X 4!J!l
CHIBA Y oshiaki f- ~ Iff IY3INAMURA Takashi flEi ti~
KAMITSUBO Hiromichi L:b1Z E. JI[
KA TSUMA T A Koichi MJ X WE KOHNO Isao riIT!fJi.J
MATSUOKA Masaru f'~ fIOj
MJ
SAKURAI Akira ~ #RX:
T ANIHA T A Isao :ft m 9§ ~YOKOO Hisaaki tl J¥. ~ IY3

AWAYA Yohko ~ m?G T
HASHIZUME Akira ~ J1\

AA*

ISHIHARA Masayasu E 1* lE *KANEKO Ichiro ~ T - f!~
KIRA Akira 5 ~~KURIHARA Osamu ~ 1*
{I~
NAGAMINE Kanetada 7k ~ ~ J~'
T AKAMI Michio ~ Je. JI[ ~W A TAN ABE Tsutomu Wi fi~
11* Chairman

Cyclotron Operation and Maintenance Group
FUJITA Shin Hi 83~
KAGEYAMA Tadashi .~!-UlE
KOHNO Isao riIT!fJj]
T AKEBE Hideki

IKEGAMI Kumio rtBL1L=~
KOHARA Shigeo IJ\ 1* ~ ~OGIW ARA Kiyoshi M( 1*m:Lt\ $ ~ W

Linac Operation and Maintenance GroupCHIBA Y oshiaki f- ~ Iff IY3IKEZA W A Eij i rtB tR. ~KAMBARA Tadashi fEfJ 1*
lE
KUBO Toshiyuki ~ 1* 4!J!l ¥Y ANOKURA Minoru ~!f~ ~=HEMMI Masatake ~ j! i1& ftt
INOUE Toshihiko # L BJ!l: ~KASE Masayuki 110 ifj l§ z
MIYAZAWA Yoshitoshi'§ ¥R {t 4!J!lScientific and Engineering Personnel

Cosmic Radiation Laboratory
IMAI Takashi ~ #~MUNAKATA Kazuoki*

KOHNO Tsuyoshi{~- ~(Visitors)
HASEBE Nobuyuki ~:ft${~fr (Fac. Gen. Educ., Ehime Univ.)
MURAKAMI Hiroyuki :f1 L fr5 Z (Fac. Sci., Rikkyo Univ.)
NAGATA Katsuaki 7k 83 MJ IY3 (Fac. Eng., Tamagawa Uri!v.)

til]!f~

325*

NAKAMOTO Atsusi Jflr~ (Fac. Sci., Rikkyo Univ.)
NISHI]IMA Kyoshi ~ ~~ ~ j§J (Sci. Eng. Res. Lab., Waseda Univ.)
YANAGIMACHI Tomoki WP OOJ J3Jj fM (Fac. Sci., Rikkyo Univ.)(Student)
KASHIWAGI Toshisuke tB* if (Sci. Eng. Res. Lab., Waseda Univ.)
flj

Cyclotron Laboratory
BE Suck Hee fl. m %=FUJITA liro Hi EB
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GOTO Akira {~lJj ~HA T AN AKA Kichij i m q:r "5 m
INAMURA Takashi fiS t1 ~KAMITSUBO Hiromichi ..t.:P¥ ~KOHNO Isao til]!frj]
MORITA Kosuke ~ 83 ~ if
NAGASE Makoto ~ tI ~NAKANISHI N oriyoshi q:r iffi *c. %SAITO Motozo
lJj 9i1
SHIKA T A Takashi IZ9 11 ~ 5t:
TOY AMA Mitsuru J! LlJ~
Y AMAJI Shuhei LlJ ~ 1~ 1fZ
YOKOY AMA Ichiro tl LlJ - ~~

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=-

FU JISAW A Takashi lJj rR rW:J itFU lIT A Shin Hi EB$JT
HARA Masahiro ®: ~ ill,.
IKEGAMI Kumio 1tB..t.1L~~
KAGEY AMA Tadashi ~ LlJ
IE
KOHARA Shigeo 11\ ®: :m: *MATSUO Masayuki f'~ If:. IE Z
NAGAOKA Ryutaro :R1iUJ~*~~
NAKAJIMA Shunji Jfl ~ ~OGIWARA Kiyoshi ~ ®:SASAKI Shigeki 1Zi:-'-< *~fM
T AKEBE Hideki ftt im ~ fM
WADA Takeshi fO 83
1Ii
YANO Yasushige ~!f 1X :m:=m(Visitors)
Vi (Reliability Cent. Electronic Components of Japan)
ANAYAMA Hiroshi 1\ LlJ(KAIST, Korea)
CHOE Byung-Ha m 1t:i I
EGUCHI-KASAI Kiyomi rIO (~it) m~ (lnst. Basic Med. Sci., Univ. Tsukuba)
EJIRI Hiroyasu rI m ~ (Dep. Phys., Osaka Univ.)~ ~ (KEK)FUKUMOTO Sadayoshi
FURUNO Kohei il!f JQ. 1fZ (lnst. Phys. Tandem Accel. Cent., Univ. Tsukuba)
GOKA Tateo Ii Jt *- (NASDA)
HARADA Kichinosuke ®:83"5ZiJ}] (Nippon Energy K.K.)~ (Reliability Cent. Electronic Components of Japan)
HARADA Minoru ®: 83
HAYASHI Nobuyuki
1$ 1T (Electro Tech. Lab.)HIRAKI Akio 1fZ B~ *- (Fac. Eng., Osaka Univ.)
HORIGUCHI Takayoshi :iftB 0 M ~ (Dep. Phys., Hiroshima Univ.)
IKEDA Kiyomi 1tB EB m ~ (Dep. Phys., Niigata Univ.)
IKEGAMI Hidetsugu 1tB..t. *!L (RCNP, Osaka Univ.)
INOUE Makoto it..t. 1"8 (RCNP, Osaka Univ.)
ISOY A Akira ~ ~ ~ (Sch. Sci., Tokai Univ.)
IWAMOTO Akira ::5
B~ (Japan Atomic Energy Res. Inst.)
IWASHIT A Y oshihisa :!6 T 75 7-.. (Inst. Chern. Res., Kyoto Univ.)
KADOY A Shingo ft.J ~ Ji:g: (J apan Gasoline Co.)
KANEKO Kumetaro ~T~*~~ (lnst. Nucl. Study, Univ. Tokyo)

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326

KASAl Shunichi rEf i§{3t - (Japan Atomic Energy Res. Inst.)
KA T A YAMA Ichiro Jt Ll! - f!~ (RCNP, Osaka Univ.)
KA TORI Kenji ,ft If)( ~(Dep. Phys., Osaka Univ.)
miWJ(Dep. Phys., Toho Univ.)
KATSURAGAWA Hidetsugu :fi )I[
KIKUCHI Fumio ~:tfu X ~ (ColI. Arts Sci., Univ. Tokyo)
KISHIMOTO Teruo J$:<$: ~ x (Dep. Phys., Univ. Tsukuba)
KOBAYASHI Shinsaku /J\ ~ it (Dep. Phys., Kyoto Univ.)
J1! (Univ. Electro-Commun.)
KOHMOTO Susumu rEf
KONDO Michiya iff: fJ Ji ili (RCNP, Osaka Univ.)
KOSAKO Toshiso /J\'f6:~~5(tt (Atomic Energy Res. Cent., Univ. Tokyo)
KOWATA Mitsuyoshi /J\ *~ 7\:; % (Reliability Cent. Electronic Components of Japan)
KUDO Hisaaki I fJ ~ BE (Dep. Chern., Niigata Univ.)
KUSAKA Takuya B T .Ej[ ili (Kobe Steel, Ltd.)LEE Young Pak~ B (RIST, Korea)
MATSUKI Seishi t'~ fiE:1:. (lnst. Chern. Res., Kyoto Univ.)
MINOW A Tatsuya jt ~ Ji ~ (Dep. Phys., Toho Univ.)
MIURA Iwao
00 :E (RCNP, Osaka Univ.)
MIY ADE Hiroki '8 ill 7.E. *~ (Sumitomo Heavy Ind., Ltd.)MIY A TAKE Hiroari '§ ~ f ili (Fac. Sci., Osaka Univ.)
MORIMOTO Y oshihide ~:<$: {t(Kobe Steel, Ltd.)MORIO Atsuo ~ ~ ~::X. (Reliability Cent. Electronic Components of Japan)
MUKHOPADHYAY, N.K. (V.E.G. Cent., B.A.R.C., India)
MURAYAMA Toshiyuki M LU flj ¥ (Tokyo Univ. Mercantile Marine)
NAGAI Yasuki ;7}c # ~ ~ (Dep. Appl. Phys., Tokyo Inst. Technol.)
NAGAMIY A Shoji 7k '§ lE m (Dep. Phys., Univ. Tokyo)
NAKAHARA Hiromichi t:p 1* "5L. Ji (Dep. Chern., Tokyo Metrop. Univ.)(KEK)
NAKAI Koji t:p # ~NAKAJIMA Kazuhisa t:p ~ - ~ (KEK)
NAKAMURA Shinya cP t1 JI~ ili (Reliability Cent. Electronic Components of Japan)
NAKAMURA Takashi t:p t1 MJ"R] (Cyclotron Radioisot. Cent., Tohoku Univ.)
NAKAMURA Yoshiteru cP M ~ ~ (Japan Atomic Energy Res. Inst.)
NISHII Masanobu gg # lE fB" (Japan Atomic Energy Res. Inst.)
NOMURA Toru If M -7 (lnst. Nucl. Study, Univ. Tokyo)
NON AKA Hideki If t:p ~ ~ (Sumitomo Heavy Ind., Ltd.)ODERA Masatoshi /J\ 1f lE {?it (Sci. Eng. Res. Lab., Waseda Univ.)
ONISHI Jun-ichi 7::. 5 *r!!, (KAWASAKI Heavy Ind., Ltd.)ONISHI Naoki 7::. ffi @: ~ (Dep. Phys., ColI. Gen. Ed,uc., Univ. Tokyo)
ONUMA Hajime 7::. m ffi* (Dep. Phys., Tokyo Inst. Technol.)OT A Shigemi :* ill jf1 ~ (KEK)P ARK Eng Soo (POSTECH, Korea)
SAKAI Hideyuki ~ # ~ 1T (RCNP, Osaka Univ.)
SAKAMOTO Hiroyuki :!:R:<$: fr5"¥ (lshikawajima-Harima Heavy Ind., Co., Ltd.)SAKAMOTO Isao :!:R:<$: ~ (Electro Tech. Lab.)(UL V AC Co.)
SAKURADA Yuzo ~ ill ~SASUGA Tsuneo •t:g ~ (Japan Atomic Energy Res. Inst.)
SA TO Kenichi 1ti Hi(Div. Phys., Tohoku ColI. Pharm.)

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327

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SHIMANO Yosuke ~ If 1$ fr- (NASDA)
SHIMAZU Mitsuyoshi ~~ (Dep. Phys., Toho Univ.)
SHINOZUKA Tsutomu 1i ~ MJ. (Cyclotron Radioisot. Cent., Tohoku Univ.)
SHIRAISHI Haruki B 15 ~ W (N atl. Res. Inst. Metals)
SUEKI Keisuke~ fr- (Inst. Nuc!. Study, Univ. Tokyo)
SUGAI Isao ;g it~ (Inst. Nuc!. Study, Univ. Tokyo)
SUN AGA Hiromi ~ 7k 11 ~ (J apan Atomic Energy Res. Inst.)
T AKEGOSHI Hidekuni 11" ~ *~ (Inst. Chern. Res., Kyoto Univ.)
T AKEMASA Tadashi ftt i& jt ± (Dep. Phys., Saga Univ.)
T AKI, G.S. (V.E.G., B.A.R.C., India)
TAKIGAWA Noboru ~ )11(Dep. Phys., Tohoku Univ.)
T AMAGAKI Ryozo .:IS: fli $'=:' (Dep. Phys., Kyoto Univ.)
TANAKA Hitoshi EE r:p:If.5j (Japan Gasoline Co.)TANAKA Jinichi EE r:p 1= m (Inst. Nucl. Study, Univ. Tokyo)
TANAKA Koki EE r:p ¥ ~ (Nippon Steel Corp.)
TASAKA Shigeki EE:t& a W (Fac. Educ., Gifu Univ.)
TOMIMASU Takio 1;~§7%x (Electro Tech. Lab.)TORIY AMA Tamotsu ,~ LlJ
1* (Dep. Appl. Phys., Tokyo Inst. Technol.)
TORIZUKA Kanji ,~ ~ % ~ (Fac. Med., Kyoto Univ.)
TSUKIJI Masaru ~:tm f~ (NEC Corp.)
TSUMAKI Koji ~~(Hitachi, Ltd.)TSUNEMOTO Hiroshi m:7L 11 (Natl. Inst. Radiol. Sci.)
VALLI Kalevi (Dep. Phys., Jyvaskyla Univ., Finland)
W AKISHIMA Susumu ~ ~ :ii (Reliability Cent. Electronic Components of Japan)
WANG Zhen (Inst. Mod. Phys., Acad. Sin., China)
WATANABE Hiroshi~ 11 it (Electro Tech. Lab.)YAMASU Kazushige 5~ ~ to:m (Mitsubishi Heavy Ind., Ltd.)YAMAZAKI Takashi LlJ ~~ (RCNP, Osaka Univ.)
YOKOTA Wataru ~ EE
~ (Japan Atomic Energy Res. Inst.)
YOKOUCHI Shigeru ~ pg
a (Osaka Vacuum, Ltd.)YOSHIDA Katsuhisa E EE :£ 1--. (Mitsubishi Electric, Co.)YOSHIDA N obuaki E EE '§' lit (Dep. Phys., Univ. Tokyo)
YOSHIDA Shiro E EE J~' ~~ (Dep. Phys., Tohoku Univ.)
YOSHINAGA Naotaka E 7k MJ ~ (Comput. Cent., Univ. Tokyo)
YOSHIYUKI Takeshi E fr
J! (Toshiba, Co.)

**

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* Visiting Professor(Students)
HARADA Shigenobu JJj( EE :m 1"§ (Dep. Appl. Phys., Tokyo Inst. Technol.)
ISHII Yasuyuki 15 it 1* 1T (ColI. Hum. Sci., Nihon Univ.)
KOBAYASHI Takayuki 11\
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KUNIHIRO Kazuaki 00 Sb. to fYj (Dep. Appl. Phys., Tokyo Inst. Technol.)
KOIZUMI Mitsuo 11\ 5R JlG.':t (Dep. Phys., Hiroshima Univ.)
MIURA Atsushi .=:. 1m]I¥: (ColI. Hum. Sci., Nihon Univ.)
OSAKI Mitsuhiro~ JlG 1$ (Fac. Sci. Eng., Chuo Univ.)

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328

SHIMOMURA Koichiro ""ffl~ -~~ (Dep. Phys., Kyoto Univ.)
1E (Fac. Sci., Toho Univ.)
SUZUKI Mitsuru ~TORII Yoshinari J~,@ ~ ~ (Dep. App!. Phys., Tokyo Inst. Techno!.)~ (Dep. Appl. Phys., Tokyo Inst. Technol.)
YOSHIDA Atsushi a EH*

Linear Accelerator Laboratory
CHIBA Toshiya T ~ flJ ~HEMMI Masatake ~ J! jJ& it
KAMBARA Tadashi t$ 1* 1£
KUBO Toshiyuki 7-.. 1:* mil
MIY AZA WAY oshi toshi '§ ¥R 1~ mil**

SUZUKI Takeshi ~Jt
TANIHATA Isao ~ m~ 7(
YANOKURA Minoru ~!f~~CHIBA Y oshiaki T}l fjf ~INOUE Toshihiko it L mil ~KASE Masayuki tlO ~ {§ Z
KUMAGAI Hidekazu ft~ ~ fD
NAKAGAWA Takahide t:p }Ir 4
TAKEUCHI Sachiko tt r0J-T
TONUMA Tadao ? m1£ 1i:t
YOSIDA Koichi a EH 7\:; -***(Visitors)
FUJIWARA Ichiro Ki 1* - ~~ (Inst. Atomic Energy, Kyoto Univ.)
ITO Noriaki W Ki :« BB (Dep. Cryst. Mater., Nagoya Univ.)
KIKUCHI Jun ~ till JI~ (Sci. Eng. Res. Lab., Waseda Univ.)..L. 3f (Inst. Atomic Energy, China)
LIU Wei Ping WP(Sumitomo Heavy Ind., Ltd.)NONAKA Hideki !f cP ~ ~SUGAW ARA Masahiko ;g 1* l§ ~ (Fund am. Sci., Chiba Inst. Techno!.)YAMAGUCHI Hiromi LlJ 0~ (Sci. Eng. Res. Lab., Waseda Univ.)m(Students)
FUKUDA Mitsunori mi EH Jl:; il~ (Fac. Sci., Tokyo Inst. Technol.)
ITO Tatsuya W Ki Jl ili (Sci. Eng. Res. Lab., Waseda Univ.)

Radiation Laboratory
ASAHI Koichiro JIg fjj:-~~HASHIZUME Akira ~!R AA
ISHIHARA Masayasu E 1* lE ~KONNO Satoshi ~!f ~TENDO Y oshihiko ~ J1! 1i ~GONO Yasuyuki ~~ I1l i'lIIJ Z
ICHIHARA Takashi
w. !j[IZUMO Koichi tJj ~ 7\:; TAKAHASHI Tan r'iSJ ~ E!.

(Visitors)
ABE Yasuhisa rm.r $ ~ 7-.. (Res. Inst. Fundam. Phys., Kyoto Univ.)
ADACHI Minoru JE JI. • (Dep. Appl. Phys., Tokyo Inst. Technol.)
ANDO Yoshiaki !fi: Ki B ~ (Dep. Phys., Rikkyo Univ.)
Didier Beaumel (Inst. Phys. Nucl., Orsay, France)
DOKE Tadayoshi J1! J~ ~ (Sci. Eng. Res. Lab., Waseda Univ.)
ENDO Saburo ~ l1i .=: ~~ (Fac. Eng., Sci. Univ. Tokyo)
FUJIOKA Manabu l1i f10j
~ (Dep. Phys., Tohoku Univ.)
HAMA Hiroyuki ~rt(Dep. Phys., Tokyo Inst. Technol.)

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329

HASEGAWA Takeo ~t:l-}I 1:Itt~ (Inst. Nucl. Study, Univ. Tokyo)
HITACHI Akira .fj I±l¥ (Sci. Eng. Res. Lab., Waseda Univ.)
HWANG Han Yull jl ~ ,t)l (Dep. Phys., Yonsei Univ. Korea)
ICHIMURA Munetake mt1 *:Itt (ColI. Gen. Educ., Univ. Tokyo)~ *D ~ (Fac. Sci., Rikkyo Univ.)
IEKI Kazuo
KAGEY AMA Mayumi ~ LlI !1! i7 (Hoyo Corp.)
KASAGI Jirota ~*m~~* (Fac. Sci., Tokyo Inst. Technol.)
KATO Norihisa DO iii 1§" ~ (Dep. Phys., Kyushu Univ.)
KATO Seigo 110 ik f!t -2f (Fac. Lib. Arts, Yamagata Univ.)
KA TORI Kenji ~ 1& ~(Fac. Sci., Osaka Univ.)
KAWAKAMI Hirokane }l1...t Ji;. ii (Inst. Nucl. Study, Univ. Tokyo)
KIT AO Kensuke ~ ~ ~*WJ (N atl. Inst. Radiol. Sci.)
KUBONO Sigeru ~1*:!f Dt (Inst. Nucl. Study, Univ. Tokyo)
KUBOTA Shinzou ~ EE 1B '=' (Fac. Sci., Rikkyo Univ.)
KUSAKARI Hideshige 1j[)(1j ~ ~ (Fac. Educ., Chiba Univ.)tEl Dt (Inst. Phys., Univ. Tsukuba)
LEE Sang Mu
MASUDA Kimiaki ~ EE 0- IY3 (Sch. Sci. Eng., Waseda Univ.)
MOTOBA YASHI Tohru ;;$:~ (Fac. Sci., Rikkyo Univ.)
MURAKAMI Takeshi t1...t f}l (Dep. Phys., Tokyo Inst. Technol.)NAGAI Yasuki 7k *1= ~ W (Fac. Sci., Tokyo Inst. Technol.)~ ~ ~ (Dep. Phys., Univ. Tsukuba)
N AGASHIMA Yasuo
NAKAYAMA Shintarou r:pLlI-Fa*~~ (ColI. Gen. Educ., Univ. Tokushima)
OHNUMA Hajimem m (Fac. Sci., Tokyo Inst. Technol.)
ORIHARA Hikonojo ~mt~~~ (Cyclotron and Rakioisot. Cent., Tohoku Univ.)~ !1! ~ (Japan Atomic Energy Res. Inst.)
OSHIMA Masumi
OY AIZU Mitsuhiro 'J'WP?$:1EJ1: (Inst. Nucl. Study, Univ. Tokyo)
RUAN (GEN) Jian-zhi ~ J!
(Dep. Phys., Rikkyo Univ.)
SAKAGUCHI Harutaka J:.& 0 m~ (Dep. Phys., Kyoto Univ.)
SAW AMOTO Takeyuki tR;;$: f}l ~ (Hoya Corp.)
SHIBAMURA Eido ~ M ~ J1! (Saitama ColI. Health)
SHIMIZU Hajime
7./(
Ii (Fac. Sci., Tokyo Inst. Technol)
SHIMOURA Susumu -r tm-¥- (Fac. Sci., Univ. Tokyo)(Dep. Phys., Rikkyo Univ.)
SHIRA TO Shoji B ± ~J\
SUGAW ARA Masahiko ;g mt J§ ~ (Fundam. Sci., Chiba Inst. Technol.)
TAKAHASHI Noriaki ~ ~ IY3 (ColI. Gen. Educ., Osaka Univ.)
TAKIGAWA Noboru t1i )11~ (Dep. Phys., Tohoku Univ.)
TOKI Hiroshi ± tl5Z iW (Dep. Phys., Tokyo Metrop. Univ.)
YAMAYA Takashi LlJ m ~ (Dep. Phys., Tohoku Univ.)
YASUE Masaharu tJi: rI IE tEl (Inst. Nucl. Study, Univ. Tokyo)
YOSHIZAW A Yasukazu a tR *D (Dep. Phys., Hiroshima Univ.)

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(Students)
FUJIWARA Hideaki ik mt ~ IY3 (Inst. Phys., Univ. Tsukuba)
FUKUDA Mitsunori 1M EE jt jlW[ (Fac. Sci., Tokyo Inst. Technol.)
ICHINOSE Hideo m~WJi*~ (Grad. Sch. Sci. Eng., Waseda Univ.)
ITO Tatsuya f¥ iii Ji t!1 (Grad. Sch. Sci. Eng., Waseda Univ.)

330

IW ASA N aohito :5 16: 00: 1= (Dep. Phys., Rikkyo Univ.)¥¥ ~ (Inst. Phys., Univ. Tsukuba)
JEONG S.C. ~KOGUCHI Masanari ~ 0 ~ J5JG (Dep. Appl. Phys., Tokyo Inst. Technol.)
MIZOT A Takeshi ~ ffi ftt $ (Inst. Phys., Univ. Tsukuba)
NAKAMURA Takashi t:p t1 ~ PJ (Fac. Sci., Univ. Tokyo)
OGIW ARA Masahiro tl( IE §b. (Dep. Phys., Rikkyo Univ.)
OGIWARA Mitsuhiko tl( :7\:; ~ (Inst. Phys., Univ. Tsukuba)
OKUMURA Susumu :!$b t1 :Ii (Inst. Phys., Univ. Tsukuba)
PU Y.H. $~(Inst. Phys., Univ. Tsukuba)
SAKURAI Mikio ~ it ~ 7:2: (Dep. Phys., Tokyo Inst. Technol.)(Dep. Phys., Rikkyo Univ.)
SHIBUYA Shinji f>Z:fr ~T AKANASHI Hidehiko ~ ~ ~ ~ (Fac. Sci., Tokyo Inst. Technol.)
TAMURA Akitoshi ffi t1 ~ 1i¥~ (Grad. Sch. O-okayama, Tokyo Inst. Technol.)
UTSUMI Motoharu P'J #Ii ~:JC (Grad. Sch. Sci. Eng., Waseda Univ.)

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Atomic Processes Laboratory
ANDO Kozo 3i: if I/llJU
HIN 0 Kenichi EI fY. KAN AI Yasuyuki ~ it f~ Z
SHIMAMURA Isao ~ t1~-=

AWAYA Yohko ~ J¥. ~ T
KAMBARA Tadashi :rEf!
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NISHIDA Masami 5 ffi *E ~W AT AN ABE Tsutomu ~ g~
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(Visitors)
FUJIMA Kazumi if Fa' - ~ (Dep. Phys., Chuo Univ.)
HARA Shunsuke W- f~ fr (Dep. Phys., Univ. Tsukuba)~ (Inst. Sci. Technol., Waseda Univ.)
HITACHI Akira }3 ttl
ISHII Keishi 15 it ~ Z (Dep. Eng. Sci., Kyoto Univ.)
ISOZUMI Yasuhito li+tf*A (Radioisot. Res. Cent., Kyoto Univ.)
ITO Shin fft J!j ~ (Radioisot. Res. Cent., Kyoto Univ.)
ITOH Yoh 1if~ (Fac. Sci., J osai Univ.)
IW AI Masahiro :5 it IE 1W (Theor. Div., Inst. Mol. Sci)KARASHIMA Shosuke ~ ~ ~ fr (Dep. Electron. Eng., Tokyo Univ. Sci.)
KA W ATSURA Kiyoshi ]II 00~ (Japan Atomic Energy Res. Inst.)
KIMURA Mineo
t1 ~ (Argonne Natl. Lab.)
KOIKE Fumihiro ;j\ t{g X 1W (Sch. Med., Kitasato Univ.)
KOIZUMI Tetsuo ;j\ ~ rg- 7:2: (Dep. Phys., Rikkyo Univ.)
KOYAMA Naoto ;j\ LlI 00: A (Dep. Eng. Phys., Univ. Electro-Commun.)
KUROKI Kenro ~ 1}t ~~ (Natl. Res. Inst. Police Sci.)
MATSUO Takashi f'~ ~(Dep. Pathol., Tokyo Med. Dent. Univ.)
MA TSUZA W A Michio f'~ ~ jffi ~ (Dep. Eng. Phys., Univ. Electro-Commun.)
MIZOGAWA Tatsumi ~ JII IN. 8 (Fac. Sci., Saitama Univ.)
NOBLE J. Cliff (Daresbury Lab., England)lJfflf ~ ~ (Inst. Mol. Sci.)
OHSAKI Akihiko
OHTANI Shunsuke
f~ fr (Inst. Plasma Phys., Nagoya Univ.)
OKUNO Kazuhiko :!$b fY fo ~ (Dep. Phys., Tokyo Metrop. Univ.)
SA TO Hiroshi 16: if 16 ~ (Dep. Phys., Ochanomizu Univ.)

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SA TO Kuninori 16: l1* 00 ~ (Inst. Plasma Phys., Nagoya Univ.)
SCHMIDT-BOCKING Horst (Inst. Kern Phys., Univ. Frankfurt)
SHIBAT A Hiromi ~ 83
~ (Res. Cent. Nuc!. Sci. Techno!., Univ. Tokyo)
SHIMA Kunihiro ~:f~ 1W (Tandem Acce!. Cent., Univ. Tsukuba)
SHIMAKURA N oriyuki ~ ~ *2. Z (Gen. Educ. Dep., Niigata Univ.)
SUZUKI Hiroshi n
1$ (Dep. Phys., Sophia Univ.)
TAKAGI Shoji ~ff ~ (Dep. Phys., Toho Univ.)
T ANIAS Monterio (Dep. Math., Royal Holloway and Bedfrod New ColI., England) .
TA WARA Hiroyuki {~ iW Z (Inst. Plasma Phys., Nagoya Univ.)
TERASA W A Michitaka ~ ¥R {ffij ~ (Himeji Inst. Technol.)
TSURUBUCHI Seiji Q mM ~(Fac. Technol., Tokyo Univ. Agric. Technol.)
URAKAWA Junji 1m III JIIW tEl (Natl. Lab. High Energy Phys.)
VOGT Hans G. (Max Planck Inst., Heidelberg)
W AKIY A Kazuyoshi 1m 1§- - ~ (Dep. Phys., Sophia Univ.)
YAMAZAKI Yasunori LlJ ~~J! (Res. Lab. Nucl. Reactor, Tokyo Inst. Technol.)

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NISHIMURA Hisashi g§ *1 !A (Dep. Phys., Tokai Univ.)
OHT A Ken
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SAKAUE Hiroyuki :I;&..tz (Dep. Phys., Sophia Univ.)*m

Metal Physics Laboratory
ISHIDA Katsuhiko n 83 1m "ffi
MA TSUZAKI Teiichiro ;f'~lIffiJtJim~~SHIOT ANI N obuhiro :tJi! 1§- B "51:.

KOY AMA Akio IJ\ LlJ BB ftl
NAGAMINE Kanetada 7k. ~ J~'
YAGI Eiichi J\**-(Visitors)
MIYAKE Yasuhiro ~ ~ ~ 1W (Meson Sci. Lab., Univ. Tokyo)
TANAKA Koki 83 t:f1 ¥ ~ (Nippon Steel Corp.)
TORIKAI Eiko J~. II!k: T (Fac. Eng., Yamanashi Univ.)(Student)
ISHIKAWA Hiroshin III

Magnetic Materials Laboratory
OKADA Takuya Ito.! EB ~ ttl.

¥1§-(Fac. Sci., Sci. Univ. Tokyo)

SAKAI Nobuhiko :l:R tt {"§ "ff(Visitors)
YAMADA Y A Tokio LlJ EB1§-~x (Fac. Lit. Sci., Yokohama City Univ.)
ASAI Kichizo ~ tt E ~ (Fac. Technol., Univ. Electro-Commun.)

Plasma Physics Laboratory
ISHIBE Yukio n ff~ 1T 1Ll

ISHII Shigeyuki

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332

OKAZAKI Kiyohiko
SAKAMOTO Yuichi/1Dj~m It"i5* tLl-

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ili ~
OYAMA Hitoshi
YANO Katsuki ~!f 1m ~(Vistors)
SUGIY AMA Kazuo ~ ili tD ~ (Fac. Eng., Saitama Univ.)
Y AMASHINA Toshiro ili f4 f?1: ~~ (Fac. Eng., Hokkaido Univ.)

Semiconductor Laboratory(Visitor)
AONO Keiko w!f:fi T(ColI. Lib. Arts, Kitasato Univ.)

Biophysical Chemistory Laboratory(Visitor)
DAI Yisheng ~ ~ 1: (Inst. Opt. Electron., Acad. Sin., China)

Inorganic Chemical Physics Laboratory
KOBAYASHI Masayoshi ;J\ ~ ~SASA Y oshihiko 1ti: /.{ ~ ~**MAEDA Kuniko iW EEl *~ T
T AKAMI Michio ~ J! ~ 1:

(Visitors)
ISHII Keizo 15 it JJ! m (Cyclotron Radioisot. Cent., Tohoku Univ.)
KUSUY AMA Hiroyuki :fffl LlI iJb. Z (Saitama Med. Sch.)MUKOUYAMA Takashi rtu ili~ (Inst. Chern. Res., Kyoto Univ.)
UDA Masayuki
EEl J;t- Z (Dep. Mater. Sci., Waseda Univ.)
FUKUDA Yukio :@ EElf3:!15 (ColI. Lib. Arts, Kobe Univ.)
MIZUGAI Yoshihiro
EB Ji;. (Dep. Phys., Sophia Univ.)
SUZUKI Atsuyuki n~ Z(Dep. Nucl. Eng., Univ. Tokyo)

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(Student)
MAEDA Haruka MEEI ~J: Q fJ>.

(Dep. Eng., Tokyo Univ.)

Radiochemistry Laboratory
AMBE Fumitoshi 11: ff~ Jt ~ARA T ANI Michi~ ~IWAMOTO Masako :fi lE T

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AMBE Shizuko 11: ff~ ~ T
ITOH Yoshiko W 7i T
OHKUBO Yoshitaka *~f*~rWJ(Visitors)
ENDO Kazutoyo
tD:Ii (Fac. Sci., Tokyo Metrop. Univ.)
FUKUSHIMA Hiroto 1M ~~ ~ A (Japan Chemical Analysis Cent.)
IMAI Masato ~ it .IE A (Komatsu Electronic Metals Co., Ltd.)IMURA Ryo it t.t:Iu (Cent. Res. Lab., Hitachi, Ltd.)

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333

KADOT A Yoshinori fF:l ill {i rl (Sumitomo Metal Mining Co., Ltd.)KAT ADA Motomi it ill JC a (Fac. Sci., Tokyo Metrop. Univ.)
KA TO Hajime 1.10 Hi - (Fac. Educ., Yamanashi Univ.)
NONAKA Nobuhiro 1Bf cp {§ iW (Japan Chemical Analysis Cent.)
OOHIRA Shigeo *:stz m ~ (Nikkei Techno Res. Co., Ltd.)SAITO Kazuo
Hi *0!J3 (Toshiba Corp., R&D Cent.)
SAKAI Youichi 1@ # ~ - (Fac. Sci., Univ. Tokyo)
It ~ -T (Tokyo Metrop. Geriatric Hospital)
SUEHIRO Makiko~ (lnst. Nucl. Study, Univ. Tokyo)
SUGAI Isao if it
TOMINAGA Takeshi • 7]< ~ (Fac. Sci., Univ. Tokyo)
WATANABE Yasuo tIt J2l m:j( (Fac. Sci., Tokyo Metrop. Univ.)**(Students)
KOBAYASHI Yoshio IJ\ ~!J3 (Fac. Sci., Tokyo Metrop. Univ.)
KUBO Kenya 7-. 1* ~ ~ (Fac. Sci., Univ. Tokyo)
MISHIMA Kenji~~ ~(Fac. Sci., Univ. Tokyo)
NAKADA Masami cP B3 IE ~ (Fac. Sci., Tokyo Metrop. Univ.)
Qui Qi ti~
1f (Res. Lab. Nucl. React., Tokyo lust. Technol.)T ACHI Kouju ~ "5b ~ (Fac. Metall., Shibaura lust. Technol.)
YU Byon Gon Jfu m:t$ (Res. Lab. Nucl. React., Tokyo lust. Technol.)

**

=

-=

Chemical Dynamics Laboratory
KIMURA Kazuie
t1 - f*(Visitor)
ITO Yasuo{j't Hi *!J3

(Res. Cent. Nucl. Sci. Technol., Univ. Tokyo)(Students)
SUZUKI Takayoshi ~ ~ ~ (Dep. Phys., Chuo Univ.)(Dep. Phys., Chuo Univ.)
UEHARA Keiji J: t!
WATANABE Kazuhiro tIt J2l -"5b (Dep. Phys., Chuo Univ.)

*

'* =

Radiobiology Laboratory
KANEKO Ichiro ~ T -~~NAKANO Kazushiro

cP 1Bf *0 ~(Visitors)
BA VERSTOCK Keith F. (Rasiobiol. Unit, Med. Res. Counc., U.K.)
EGUCHI-KASAI Kiyomi(~it) m~ (Inst. Basic Med. Sci., Univ. Tsukuba)
KANAI Tatsuaki ~ it Ji ~ (Natl. lust. Radiol. Sci.)~ (lnst. Clin. Med., Univ. Tsukuba)
MARUHASHI Akira J:L ~McINTYRE Cindy L. (Radiobiol. Unit, Med. Res. Counc., U.K.)
SUZUKI Keiji ~ @F"Pj (RI Cent., Fac. Med., Yokohama City Univ.)
WATANABE Masami tIt J2l IE a (RI Cent., Fac. Med., Yokohama City Univ.)
YAMASHITA Shoji LlI T {§ {J\. (Natl. Saitama Hospital)

rID

*

334

(Students)
KOSAKA Toshifumi /j\:l;& 1~)( (Dep. Vet. Radiol., Nihon Univ.)
SUZUKI Masao~(Fac. Med., Keio Univ.)

n* mSafety Control Affairs Office
KAGAYA Satoru nD~~ 'iN
KURIHARA Osamu ~ W1~
MIYAGAWA Makoto '8 }II ~ ~SAW A Hiroshi ~7Z.
USUBA Isao ¥f. ~~KATOU Takeo no ~ ~ fLit
MA TSUZAWAY asuhide t'~ 1R !fi
SAKAMOTO Ichiro :l;&a~
SHINOHARA Shigemi ~ w- a c

Surface Characterization Center
IW AKI Masaya :!5 IE ~SAKAIRI Hideo :l;& A ~ fLit

KOBAYASHI Takane*(Visitor)
FUJIHANA Takanobu(Student)
KOBA YASH! Kenzo~ 1E ~ W

Jj\*-(Advanced Technology Inc.)** -at -= (Fac. Eng. Sci., Osaka Univ.)

Laser Science Research Group
J1t
NAMBA Susumu ~ i&:

Ij\

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AIHARA Toshimitsu E
flj 7'6 4
AKAGI Hiroyasu iffi
7X. 3i: 2. h'nf( -rr fitkr
83,121,122 , 124,125,
AMBE Fumltos I ~ 1=IiJ .x.. Jy:)l 127,150,152

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ANDO Kozo 3i: ~ IftHU':::' 70
ANDO Yoshiaki 3i: ~ ~ ~ 18,174
AOKI Ichiro w*11l*Df1~ 288
AONO Keikoff :ti T 99
AONO Masakazu w ff iE fD 91
ARAI Eiichi $Jf 1*
109
ARA T ANI Michi~ ~ ~ 109,111 , 113,115
ASAI Kichizo ~ 1* E Ji 84,121,122,125w*m

AWAYA Yohko ~ m?& T
BE Suck Hee~~ ~199 , 276,279 ,281 ,283,286,
288,290,292

ll~ %

<iX

~!:f~962,68,70,72 ,BARVERSTOCK K.F. 139
BOHNE Worfgang 164
CHIBA Toshiya T ~ f lj ~ l49
CHIBA Y oshiaki T ~ fjf fYj 4
CHIHARA Teiji T~ {x. 124
DOKE Tadayoshi ~J~' ~ 10,168,170,172
EGUCHI-KASAI Kiyomi rID (~1*) m~ 133
EKUNI Katsuaki rI 00 5l BB 12
ENDO Kazutoyo Ji ~ fD:B: 121,152
FU JIHAN A Takanobu ~ it ~ 'N 93,95
FU JIMA Kazumi jfi Fa~ - ~ 45
FUJIMOTO Takashi ~;;$:~ 52
FU JISA W A Takashi ~ rR rfiD it, 196 , 211,222,225
FUJITA Jirou jfi EEl
f1~ 184
FUJITA Shin ~ EEl~ 301,303,307
FU JIW ARA Hideaki B~ ~ 18,157,166
FUKUDA Mitsunori mi EEl 7'6 }Ij& 8,10
FUKUSHIMA Hiroto mi ~~ ¥15: A 107
J~ -;1iJ;~
2,202,203 , 205,207,209,
GO TO Ak '

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HARA Shunsuke '*HARA Masahiro~/

211,213,215~Ii: 'JJ.J.

227,231,235,238,
242,245,248,253,
259,265,268,271 ,
273,295,297,299

1~ fr

49

~ ~f

··· MIl r-h:±: ~ 2,133,148,202,
HATANAKA KichIJ1 ~1Il 'I' l=l {O 219,222,225
HAYAKAWA Shun-ichiro !j!}I11~-f1~ 148
HA Y ASHI N obuyuki
f$ 1T 105HEMMI Masatake ~ ~ jJ& j\ 4
HINO Ken-ichi El"-! f {}l - 35,38,40
HITACHI Akira J=3 tfj~ 54,55HOSHINO Tetsuro £ ff rg- f1~ 178
ICHIHARA Takashi~ 8,144,148
ICHIKAWA Shinichi m) II Ji - 20,21
IEKI Kazuo *:fP.Jt fD ~ 18,174
IIMURA Hideki i&. fl
20,21
IKEGAMI Kumio nE..t1L~~ 199,202,213
IKEG AMI Y uj i nE..t ttl
133, 152
IKEZAWA Eiji tIE tR ~4,219
IMAI Takashi ~ 1*
~ 168,172
IMURA Ryo 1* M % 109
INABA Takayuki fm ~ :I: ~ 74

**

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IN AMURA TakashI

f~ t+

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1"18 'r'.!

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20,21,144,176,
178,180,182,307

INOUE Koji 1*.t. ~ ~ 268
INOUE Toshihiko 1*..t w.!z ~ 4
ISHIDA Katsuhiko E EEl Jm ~ 153,155
ISHIHARA Masayasu E
iE ~ 18,148
ISHIHARA Takeshi E:It\ 49ISHII Keizo E 1* It J§ 60
ISHII Shigeyuki E 1* PX 1T 222,225
ISHIKAWA Hiroshi E) II 1'15: 79,81
ISHIKA W A Toshiyuki E) II 1~ 1T 2
ISSHIKI Hiroshi - ts m 2
ITO Tatsuya 11l ~ J.i ili 10
ITOH Susumu fft ~ Ji 102
ITOH Y oshiko 11l 1.i T 107
IWAKI Masaya :E- iE -ijlt 86,91,93,95,99+ iE -=z. 83,121,122,127,
IWAMOTO Masa k 0 ::c 4-'T
150,152,301

'*
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*

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I-W

IWASA Naohito. :E- ~ Ii 1= 18,174
JEONG S.C. ~r~ ~ 18
KADOT A Y oshinori ftl'3 EEl 1*
107
KAGA Y A Satoru 11D ~ m 't.g 301
I
iE . 6207,211, 202 , 203 ,KAGEYAMA T a dash1· .!iV
.ij'~ I-Ll

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HASEBE Hiroo *~g~mtl 4
HASEBE N obuyuki *~g~f~1T 10,168,170,172
HASHIMOTO Hirokazu ~7Z. fD 115
HASHIMOTO Iwao ~fa 86

KAJINO Toshitaka ~ ff w.!z it 16
KAKUl Hideo ftl'31* B /:Btl 281

HASHIZUME Akira ~ JT\

KAMITSUBO Hiromichi ..t PjZ 7X. J1! 305,307
KANAI Tatsuaki ~ 1* Ji ~ 133*

HA T A Kazuhiro~*

AA i~i ~i9~87 ,189,

fD m 18

K AMBARA Tadashi ~$'*iE 54,55,57,62,68,
72,74,149

KANA I Y asuyu k I·

54 , 55 , 62 , 68, 72 , 74 ,149

A
-t+ JQ -7.:ilZ 7117T' K..

KANEKO Ichiro iz -T - ~~ 133,137,139,141
KARASHIMA Shosuke~ ~ 11'- 45
KASE Masayuki
iii l§ Z 2,4,62,200,202,217
KASHIWAGI Toshisuke {8flJ 11'- 10,170,172
KA T ADA Motomi h EE JG i3 83,122,124
KATAYAMA Toshiko h W1#!z -T -- 133
KA TO Haj ime~
113
KATO Seigo
D 1% 148
KA TO Takeshi~~ 111,113
KA TOU Takeo~ ~301
KA TSURAGA W A Hidetsugu f!) II
PtiiTI 75,

m

no

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no:§
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no

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176,178,180
105
131

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KA W AHARA Hiroyuki til]
1W Z
KA W ANISHI Shunichi til] 1§ 13t: KAWASE Yoichi )11 w~ ~ - 125
KIKUCHI Jun *J tili
JI[W 10,168,170,172
KIMURA Kazuie *:f.t - f: 128
KIT AO Kensuke ~37 ~.WJ 187,189,191,194
KIT AZA W A Hideaki ~t ~ ~ IY3 153
KOBAYASHI Kenzo IJ\f}l ~ 93**

KOBAYASHITakane IJ\**
KOBAYASHI Toshio Ij\
KOBAYASHI Y oshio d\** 13t: m**~ ~KOHARA Shigeo IJ\ lffi ~ ~KOHMOTO Susumu roT
KOHNO Isao ril] IT:c}]~6il,93,97,•

8,12,14
83,121,122,124~i~96,202,209,211,

*

J1§

70

~6j05,121,130,131,301,

KOHNO Tsuyoshi rilJ IT~ 168,172
KOIZUMI Mitsuo IJ\ 7~ 7't ~ 180,182
KOKAI Hideki d\ #Jj
W 102
KOSAKA Toshifumi IJ\:l:bZ 13t:)( 133,135,139,141
KOSAKO Toshiso IJvf~c!J11J~tt 305
KOY AMA Akio Ij\ W 8B fjj£ 79,81
KUBO Ken-ichi !A. 1:* ~ - 16
KUBO Kenya !A. 1* ~ -ijIt 121,152
KUBO Toshiyuki !A. 1* tti!z ¥ 8,10,148,170
KUBONO Shigeru !A. 1* IT
148. k azu d~"" :21<::: to10,21,62,65,
KUMAGAI HIdeflR:e- F.i I)'
128,135*a·
KUMA T A Y u k 10

fj~ EE .:;f;- ~"R

KURIHARA Osamu
KURIMOTO Kazuya
KURIY AMA Kazuo
KUSAKA Takuya

=F

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*** W-

196,202,203,209,
211

1~
~

.£j.l-h
B ~I' .!:f'u:.

301

-ijIt

115

105
265,268,271,273,
276,295

KUSAKARI Hideshige 1j[)(1J ~ %: 20,21
KUSUY AMA Hiroyuki ;fffl III ~b Z 119*a

LEE S.M.
;f§
18,147,157,166
LIU Wei Ping 1PP
mi ~ 10,170
MAEDA Haruka iWEE ti ~ ir" 77
MAEDA Kazushige iW EE fO
148
MAEDA Kuniko iW EE ~ -T 60,117,119
MARUMORI Toshio 11 ~ ~ ~ 27,31
MA TSUKI Seishi :f'l
fiE!t: 182
MA TSUMOTO Takehiko :f'l~"ffi 97
MA TSUMOTO Y oshiyasu :f'la
77 ,180
MATSUO Masayuki :f'l ~.1E Z 27,29,31
MATSUO Takashi :f'l ~65
MA TSUZAKI Teiichiro :f'ltlf~Hffirm~~ 153,155
McCINTYRE Cindy 139
MINEHARA Eisuke ~~ 11'- 20,21
MINOH Arimichi ~ e±J :tE J!! 222,225
MINOWA Tatsuya ~ ~ Ji -ijIt 75,176,178
MISHIMA Kenji ~ ~~ ~121
MIURA Atsushi ~ 00
fJJ. 268,273
MIY ADE Hiroki '8 ili 7R *c. 297,299
MIYAGAWA Makoto '8 JII ~ ~ 301
MIY AHARA Akira '8 lffi
8B 102MIYAKE Y asuhiro ~ t ~ 1W 153
MIY AZA WAY oshi toshi '8 iR 1~ 11J~ 4
MIZOGAWA Tatsumi m)11 ~ B 54,55,62
MIZOT A Takeshi ~ EE ~ ~ 18,157,166
MIZUGAI Yoshihiro 7.K 1§. EB 'JZ. 77
MOKLER P.H. 57

a

*

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* *

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MORIMOTO Yoshihide ~MORITA Susumu

~ EE

* *
1~

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279,281,283,
286,288,290,
292

60

MOTOBA Y ASHI Tohru~ 18
MOTON AGA Shoushichi JG 7k 8B -I:; 262
Muller Alex C. 57
MUN AKA T A Kazuoki
1~ - ~ 168,172.
k· ~ L ~ -7 10,18,168,
MURAKAMI HIroyu I 1"J -L {Q K.. 170,172,174*

MURA Y AMA Toshiyuki ;f'1 LlJ flJ ¥ 18,180,182
N AGAMINE Kanetada 7k ~ ~ J~' 153,155
NAGAOKA Ryutaro~~~::t~~227,231,235,238,
242,245,248,253,
259

N AGASE Makoto ~ W~
~ 200,202,211
NAGASHIMA Yasuo ~ ~18
N AGA T A Katsuaki jj( EE Jm IY3 168,172
NAKADA Masami $ EE .1E ~ 121*x

NAKAGAWA Takahide$ 111 i1*

8,10,147,
157,159,162,
164,166

NAKAHARA Hiromichi $ lffi ~b jg 121
NAKAJIMA Mitsuo cP ~ 1E ~ 115
NAKAJIMA Shunji t:p ~ ~199=

NAKAMOTO Atsushi q:t;2$:
1~ 170,172
NAKAMURA Takashi q:t f1 ri16 'j§fj 148
NAKANISHI N oriyoshi t:p g!j *,c. ~ 203,305
NAKANO Kazushiro t:p my tD ~ 133,135,137,
139,141

N AMBA Susumu fit 1Hz
Ji 93,99
NISHI Katsuo gg~ ~ 152NISHIDONO Toshirou g!j ~ m!z fl~ 281
NISHI! Masanobu gg # .IE {~ 131
NISHI]IMA Kyoshi i§ ~~ ~ 'j§fj 170,172
NONAKA Hideo !f q:t ~ ~ 2,219
NON AKA Nobuhiro !f t:p {~1W 107
NOZAKI Tadashi my ~ IE 107
OGAWA Masao /J\)lI;f!£ ~ 115
OGIHARA Mitsuhiko ~ 1* :Jlt ~ 18,157,166
OGIW ARA Kiyoshi ~ 1*
~ 6,196
OG IW ARA Masahiro ~ 1* IE sf:,. 18,174
OHKI Tomonori "*~ ~U 4*125,127,150,

OHKUBO Yoshitaka " "*~f*Af,iU 187,189,191,
194

OHNISHI J un-ichi "* i§ ~ - 262,276
OHNUMA Hajime "* rB
m 148
OHTA Ken 7( EB
W 74
OHT ANI Syunsuke "* -ti- 13t fr 74
OIKA WAY oshifumi ~) II A ~r) 281
OKABE Y oshio ftnj g~ H 11t 95
OKADA Takuya

ftnj EB ~ -tl1~~584,121,122,124,

OKUMURA Susumu ~ f1
Ji 18
OMA T A Kazuo /J\ {~ tD ~ 14
ORIHARA Hikonojo ~1*~zB1& 148
OSHIMA Masumi "* ~ ~ ~ 20,21
OSHIRO Yukimitsu "*:IJ!X"*:Jlt 222
OTSUKA Masahisa "* ~.IE ~ 111
OTSUKA Shozo "* ~ ~'':::' 2
OTSUKI Masayoshi~ @§ ~ 176,178
OY AMA Hitoshi "*~ 102
PARK Eung Soo 1+ JJ! -* 262
PU Y.H. 1m ~ m 18,157,166
QIU Qi li~
1f 109REUSCH Stefan 57
RUAN (GEN) Jian-Zhi ~ m rEi 18
SAITO Motozo
J1i M1.:::. 202,211,215,217
SAKAI N obuhiko :!:& # {~ill 84,121
SAKAI Y oichi ?§ # ~ - " 121
SAKAIRI Hideo :!:& A ~ 11t 7,91

"*

w

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* $
*-

SAKAMOTO Hiroyuki :!:&¥~SAKAMOTO Ichiro :!:&

fl~279,281,283,
286,288,290,
292

301,303,307

SAKAMOTO Isao :!:&;2$:
Jk 105SAKAMOTO Yuichi :!:&;2$: 11£ - 102
SAKA T A Fumihiko :!:& EB X ill 27,29,31
SAKA UE Hiroyuki :!:& 1: mZ 74
SANO Hirotoshi ftc!f 1W m!z 83,121,122,124
SASA Yoshihiko ftc k • ~ 60,79,81,84,117,119
SASUGA Tsuneo :I- ,@~ ~ 131
SA TO Kenichi ftc J1i
33
SA TO Toshihiko ftc J1i m!z ~ 111
SCHMIDT-BOCKING Horst 72
SCHUCH Reinhold 57
SEGUCHI Tadao 11 0 J~ ~ 131
SHIBUY A Shinji ~ -ti- ~18
SHIKA T A Takashi IZ] 15 ~ ~ 305
SHIMA Kunihiro ~*~ tf 54,62
SHIMAMURA Isao ~ fl
~ 47,52SHIMANO Yosuke ~~ 1I!f 1$ fr 104
SHIMIZU Hajime ~ 71<• 148
SHIMODA Tadashi T EEl
IE 12
SHIMOMURA Kohichiro T~1~-fl~ 182
SHIMOURA Susumu T 7m¥" 12
SHINOHARA Shigemi ~ 1* ~ a 301
SHIRAKURA Takao B ~ :I- 1l1£ 292
SHIRA TO Shoji B ± ~J\
18
ST ACHURA Zbigniew 57
STOLTERFOHT Nikolaus 68
SUEKI Keisuke~ fr 187
SUGAI Isao -g #Jk 113,180
SUGAWARA Masahiko -g 1* @§ ~ 20,21
SUGIMOTO Kenzo ~;2$:.':::' 12,14
SULIK Bela 55,68
SUNAGA Hiromi ~ 7.k 1W ~ 130
SUZUKI Atsuyuki if;
Z 77
SUZUKI Hiroshi if;
1$ 74
SUZUKI Keiji if; ~ n] 141
SUZUKI Masao n~ 11t 137,141
SUZUKI Takayoshi n~ i1& 128SUZUKI Takayuki if; ~ Z 75
SUZUKI Takeshi if;
8,10,170
T ACHI Kouju ~ sf:,. W 107,111
T ACHIKA W A Toshiki fL)l1 4J!z fM 203
T AJIMA N orio EB ~ $ ~ 135
TAKAHASHI N oriaki f,iU fit
fY3 12
TAKAHASHI Shigeo f,iU fit ~ ~ 200
TAKAHASHI Tan ~ ~.§. 133,135
T AKAMI Michio r'SJ J! J1! ~ 60,77,180
TAKAYANAGI Toshinobu r'SJ ~D {~~ 74
T AKEBE Hideki 1£\ $ ~ fM 2,200,202,203
T AKEKAW A Shunji 1'1)11 13t
91

*

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=

=

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*

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*

*

*

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TANAKA Hitoshi

j$J

227,231,235,238,
242,245,248,253,
259

T AN AKA Koki E8 r:p $ ~ 100
TAN AKA Ryuichi E8 r:p ~ - 130
TANIGUCHI Yoshiki t:t- 0 ~ W 196,222,225
TANIHATA Isao ~~:j( 8,10,12,14,16,147,m

159,170iW Z 65
TENDOW Yoshihiko 7( J!t Jj ~ i~~' 189,191,
1~

TAW ARA Hiroyuki

TOKI Hiroshi ± tl5tiW 16
TOMINAGA Takeshi ~ 7k
00 121TONUMA Tadao p mIE a 65,70
TORIKAI Eiko ~. ~ T 153
TOYOKA W A Hidenori :!': JII
wI! 148
TSUMAKI Koji ~~227,231,235,238,242,

* m
o

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245,248,253,257,259=

TSURUBUCHI Seiji ~ mM ~70
UDA Masayuki ~ E8 Jit Z 60,117,119
UEHARA Keiji ..t ®: ff
128
UEHARA Shin-ichi ..t ®: Ji - 125=*'

URAl Teruo 00 if
x 7
VEG H Laszle 42
VOGT Hans 72
WADA Takeshi fD ill
1Lt 144,186,273
W AKASA Shuichiro ;fi~*-f!~ 148
W AKIY A Kazuyoshi ~ ~ - ~ 74
W ARCZAK Amdrzej 57
W A T AN ABE Hiroshi *~ ~ iW;:&: 105
W AT AN ABE Kazuhiro Vi JZl - ~L 128
W A T AN ABE Masami ?1i JZl IE a 141
W A TAN ABE Shu ?1i ff~=* 133WATANABE Tokuji ?1i JZlfz m 133
W A T AN ABE Tsutomu ?1i ff~
W AT AN ABE Yasuo ?1i JZl
WINTERMEYER Gerd 57

11 ~~' 38,40,42,

mx 121,152*

YAGI Eiichi J\-* - 7,86,88,97,100
YAMADA Yutaka LU ill:!': 133,135
YAMADAYA Tokio LUillt:t-~x 84
YAMAGUCHI Hiromi ill 0~ 10
YAMAGUCHI Hiroyuki ill 0 ~L Z 86
Y AMAH Shuhei LU ~ 11~:lfZ 23,25
YAMAKAWA Osamu ill JII
1~ 14
YAMASHITA Shoji LU T ~ <!x 137
Y AMASU Kazushige 51]\ ~ fD:m: 297,299
YAMAZAKI Hiroshi LU IWfr iW ~ 124
YAMAZAKI Yasunori LU IWfr ~ ~Jl 68m

YANAGIMACHI Tomoki WP IIIJ ~}j W 10,168,
170,172
Y ANO Katsuki ~ my 1m % 102,YANO Yasushige ~ my ~:m: 2,148,202
Y ANOKURA Minoru~ my ~ ~4,10,102,109,
111,113,150,
170,301

Y ASUE Masaharu !i iI IE m 148,186
Y A T AGAI Fumio .ft.illffit)(x 133,135
YOKOTA Wataru ;fi ill~ 219
YOKOUCHI Shigeru ;fi pg
Dt 279,281,283,286,
288,290,292

YOKOYAMA Ichiro ;fi ill - f!~ 200,217
YONEDA Akira
ill
~ 168
YOSHIDA Hyogo ~ ill ~::g: 148*

227,231,235,

YOSHIDA Katsuhisa

a B3 5l 7-. 238,242,245,
248,253,259

YOSHIDA Kenichiro aill~-f!~ 119
YOSHIDA Kenzo a ill {}t ~ 130
YOSHIDA Koichi 5" B3 j[; - 8
YOSHIDA Shiro a B3 J~J f!~ 33
YOSHINAGA Naotaka 5" 7k fEij ~ 23,25
YOSHIYUKI Takeshi afT

00 265,268,271,

YUASA-NAKAGAWA Keiko

r:p Jilli: T

ZHUO Yizhong.Ej[~ J~'

276,295

27,31

157,
159,162,166

RIKEN Accelerator Progress Report
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