UTTAC-70, 2002

ANNUAL REPORT
April 1,2001 – March 31, 2002

TANDEM ACCELERATOR CENTER
UNIVERSITY OF TSUKUBA

http://www.tac.tsukuba.ac.jp/

PREFACE
This annual report describes research activities in UTTAC during the period from April 2001 to
March 2002. The 12 UD Pelletron tandem accelerator was successfully operated until the end of
February 2002. Total beam time used for experiments was 1729 hours. This time is about 64 % of thatin the last year. The decrease of the beam time was due to the fact that we were forced to stop theaccelerator every weekend from the lack of manpower. The duoplasmatron source of the tandetron
accelerator was improved to produce negative helium-ions more stably.
In nuclear physics, we obtained a new experimental data on the proton polarization in the208

Pb(d,p)209Pbgs reaction at 20 MeV, and on the analyzing powers in the 6Li(d,p)7Li reaction at 90 keV.

Further investigation was made on the anomaly in the total-reaction cross section for protons on Si
nuclei near the (p,n) threshold. An extension of our CDCC analysis yielded a new prediction of triple
differential cross sections for the 208Pb(d,pn) reaction at 56 MeV with polarized deuterons. Nuclear
structure studies were performed on 116I and 117I. A polarized proton beam was applied to investigate
the transient magnetic field applied on fast ions moving through magnetized foils.
 Ion-induced secondary electron spectroscopy, atomic cluster physics, NMR studies on electronic
states of 3d transition-metal oxides, Moessbauer experiments and the elastic property of metals after
proton irradiation were continuously performed since the last year. A new technique was developed ona method of real-time analysis of deuterium atoms introduced into solid material by deuteron ion
implantation. An experiment was initiated towards the fabrication of microstructures by heavy-ion
bombardment.
A systematic investigation was carried out on the transmission of atomic and molecular negativeions through the 12UD Pelletron tandem accelerator. The development of a microprobe system forhydrogen analysis initiated in the last year was continued. In addition to resonant nuclear reaction
analysis, we developed an elastic recoil coincidence analysis using proton-proton scatterings at around
20 MeV. The high penetrability of protons with high-energy and low stopping power has opened theanalysis of hydrogen which is confined in fluid inclusions in silicate samples over the thickness of 0.2
mm. We tested a method of the suppression of nuclear gamma-ray background in NRA for thicksilicate samples. In order to provide experimental data for the neutron dosimetry of Hiroshima atomic
bomb, AMS measurements of 36Cl were performed for samples that were taken at several places in
Hiroshima city.

                            Kohei Furuno-i-CONTENTS
1. ACCELERATOR AND EXPERIMENTAL FACILITIES
1.1

Accelerator operation 2001...................................................................................................... 1

1.2

Calibration of the beam analyzing magnet with the adjustment of the image slit ................... 5

1.3 Transmission of ions in 12UD Pelletron Tandem Accelerator for the injection ofnegative single ions and of negative molecular ions ............................................................ 7
1.4 Microprobe system for hydrogen analysis of mineral samples.............................................. 10
1.5

Solution for the pulse height defect of MSTPC..................................................................... 14

1.6

Effect of minimum strength of mirror magnetic field on production of highly charged ionsfrom RIKEN liquid He free super conducting Electron Cyclotron Resonance Ion Source(RAMSES).......................................................................................................................... 17

1.7

Radiation safety at tandem accelerator center ....................................................................... 19

2. NUCLEAR PHYSICS
2.1

Elastic and inelastic scattering protons on natSi at 28Si(p,n) threshold energy region........... 24

2.2

CDCC analysis of triple differential cross section of 208Pb(d,pn) reaction at Ed=56 MeV .... 26

2.3 Analyzing powers for the 6Li( d ,p)7Li reaction at an incident energy of 90keV .................. 30
2.4 Measurement of proton polarization in 208Pb(d,p)209Pb reaction atincident energy of 20 MeV ................................................................................................... 31
2.5 The 6Li(d, α)4He reaction at an incident energy of 90 keV ................................................... 32
2.6 Spin precession measurement of polarized proton ions by transient magnetic field ............. 34
2.7High spin states in 127I............................................................................................................ 39

2.8 Determination of excitation energies and level structure in high-spin states of 116I .............. 43
2.9

Detection of Rn-flux in the atmosphere................................................................................. 51

3. ATOMIC AND SOLID STATE PHYSICS, AND CLUSTER SCIENCE
3.1

Resonant ionization of channeled dressed ions in a crystal field........................................... 53

3.2

Electron emission from Si crystals bombarded by fast Ag ions ............................................ 56

3.3

Anomalous elastic property of nanocrystalline gold ............................................................. 58

3.4

Fabrication of microstructures in rutile TiO2 single crystal using structural change
induced by swift heavy-ion bombardment.......................................................................... 60

3.5 Measurement of retained deuterium density in metals after deuteron implantation.............. 62
3.6 TOF spectra of dissociated molecules by photon/HCI impact in crossed-beamapparatus for cluster fission experiment ............................................................................. 64
3.7

Cluster abundance spectra of low melting temperature metals produced bybombardment of 6 keV Xe atoms. ...................................................................................... 66

3.8

Simulations on gold and copper clusters ............................................................................... 70- iii -

3.9 Mössbauer study of α’’-Fe16N2 foils prepared by a nitrogen plasma irradiation method ...... 72
3.10 Mössbauer study of superconducting YFeSr2Cu2O6+δ compounds...................................... 75
3.11 The science of 3d transition-metal oxide system ................................................................. 78

4. ION BEAM APPLICATION
4.1

Suppression of nuclear-cascade gamma-ray background analysis ........................................ 82

4.2 Hydrogen analysis by proton ERCS technique..................................................................... .86
4.3 Status of Tsukuba AMS system ............................................................................................ .89
5. LIST OF PUBLICATIONS ....................................................................................................91
6. THESES ...............................................................................................................................95
7. SEMINARS ..........................................................................................................................96
8. SYMPOSIUM ......................................................................................................................97
9. LIST OF PERSONNEL .........................................................................................................98- iv -

1.1

Accelerator operation 2001

K. Sasa, S. Ishii, H. Kimura, H. Oshima, Y. Tajima, T. Takahashi, Y. Yamato,
T. Komatsubara, K. Shima and K. Furuno
The operation of the 12UD Pelletron tandem accelerator was very stable for the period from April in2001 to March in 2002. The total operating time and the experimental beam time were 2223.1 and 1729.0
hours, respectively. The operating time decreased by about 36 % as compared with that in 2000, because
we did not operate the accelerator every Saturday and Sunday. Fig.1 shows the distribution of operation
hours every month. The beam time at various terminal voltages is shown in Fig.2. Fig.3 presents thesummary of accelerated ions and fractions of their beam time for three ion sources. Fig.4 shows thepercentage of experimental beam times for research fields.

Machine Operation Hours

250

200

150



100

50

0

Fig.1

2001
Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

2002
Jan

Feb

Mar

Accelerator operation hours per month from April in 2001 to March in 2002.

11 MV
10 MV
Terminal Voltage

9 MV
8 MV
7 MV
6 MV
5 MV
4 MV
3 MV
2 MV
0

50

100

150

200

250

300

350

Beam Hours

Fig.2

Beam time summed up every 1 MV of terminal voltages.

-1-

400

AMS
Ion Source

35Cl
0.8
36Cl
2.5

12C
0.4

2H
5.4

1H
22.0%

Polarized
Ion Source

2H
3.8
1H
32.8

11B
0.6
12C
6.4

SputterIon Source

14N
2.6
16O
4.2
197Au
0.2
127I
0.9

Fig.3

19F
7.6

107Ag
2%
79Br 63Cu 48Ti
2.1 1.8

40Ca
0.4

35Cl
2.2

28Si
1.0

Accelerated ions and fractions of their beam time for three ion sources.

Developments(Instruments andDetectors)
4.0%

Others0.5%

Accelerator Science
3.8%
Atomic and Solid
State Physics
25.5%

Nuclear Physics(nuclear reaction)
30.9%

AMS
3.7%
Earth Science
7.8%
Nuclear Physics(polarization)
23.8%

Fig.4

Percentage of experimental beam times for research fields.

The scheduled maintenance was finished on April 6 in 2001. After voltage conditioning and beamtransport tests, we provided beams for experiments from May 9. In the year of 2001, some modificationsof beam lines were carried out. In the first target room, the crystal ball and the heavy-ion post accelerator
on the 0° beam line were shut down. A new microprobe system for hydrogen analysis of mineral samples
was set up instead of these equipments [1]. A small general-purpose scattering chamber and a polarized
deuteron target were constructed on the D-beam line (1-D). The latter was developed by the researchgroup of Nagoya University as a joint project. A new experimental chamber for the measurement of thetotal reaction cross section was set on the B-beam line (2-B) in the second target room. The study of
proton irradiation effect on metal at low-temperature was reopened on the D-beam line (2-D). Fig.5 shows
the present beam courses.

-2-

Plane figure of the experimental rooms
1-B Micro-PIXE forthe earth sc ience

1-D
Polarized d target system.

Second target room

Quadrupole
magnetChanneling ef fect
for crystallography

First target room

General-purpose scatteringchamber.

ECR
ion source

1-C
Switchingmagnet0°-lineMicroprobe system
for hydrogen analysis

Clus ter physics

2-E

SwitchingmagnetLarge scatteringchamber

Steer er

Analyzing magnet

26.4 m

1-E

2-D

Magnetic
spectrograph(ESP-90)

14.7 mNew scattering chamber
for t he study of total
reaction cross sect ion

1-F

2-C

2-B

AMS

Low-t emperature metallic
ion quantities

55 m

Fig.5

The present outline of each beam course.

In the year of 2000, we lost SF6 gas by 656 kg in the operation of the gas handling system. This was aserious problem for us, so that we repaired the seal of the connecting rod of the SF6 gas compressor. It was
the main part of the gas leak found on May in 2000 and on January in 2002. After this repair, the gas
leakage was decreased. The total gas leakage was however still 277 kg in the year of 2001.

(a)
Fig.6

(b)

(a) The bearing points of the corona needle shaft under repairing.

(b) The leaking test of the repaired corona needle shaft using high-pressure N2 gas.
The scheduled maintenance in the spring of 2002 was started from March 7 and finished on April 4.
The major works of this maintenance were as follows. All corona points were replaced along the column
and the accelerating tube. Stripper foils in A and B foil changers were also replaced by new foils. We
repaired or replaced the oiling system, the shorting rod contacts, the insulating tire of the chain pulley. We-3-found several leak points of SF6 gas on the main accelerator tank. The leak at viewing port flanges and at
the feedthrough of the corona needle shaft were large. We replaced the flanges and repaired thefeedthrough. Fig.6 shows the leak test of the repaired corona needle shaft using high-pressure N2 gas. We
added 1000 kg SF6 gas to the main accelerator tank at this time.
The total operating time of the 1 MV Tandetron accelerator was 350 hours for the period of 2001. The
duoplasmatron ion source for He- production was frequently shut down since 1999 [2]. It was caused bythinning down and breaking of the lead wire connected to the solenoid coil in the duoplasmatron ion
source. We modified the lead wire using thicker wire and operated carefully. Since the purity of present
cooling water is not so high, we are preparing to replace it by electrolysis-free organic coolant(ethylene-glycol).
References[1] K. Sasa et al., Hydrogen analysis of mineral samples at University of Tsukuba,
Nuclear Instruments and Methods B 190 (2002) 287-290.
[2] K. Sasa et al., UTTAC68 (1999) 1.

-4-

1.2

Calibration of the beam analyzing magnet with the adjustment of
the image slit

K. Sasa, T. Komatsubara, S. Ishii, Y. Yamato, H. Oshima, T. Takahashi, H. Kimura, Y. Tajima,
K. Shima and K. Furuno.
A serious problem in our beam transport system has been the movement of focus produced by thequadrupole doublet in front of the switching magnet. This movement was due to the misalignment ofbeam emerging from the image slit of the analyzing magnet to the axis of the quadrupole doublet. It wasserious to carry out microbeam experiments and precise measurements of nuclear reactions. We performed
beam transport tests for the first and second target room. The walk of the focused beam was minimized by
the displacement of opening in the image slit of the analyzing magnet. We displaced the center of the
opening in the image slit by 1 mm upward for the first target room, and by 1.5 mm for the second target
room. The opening position was adjusted by observing movements of the focus on a ZnS plate. The
displacements of openings necessitated a new energy calibration of the analyzing magnet.
The energy calibration was performed by measuring excitation functions of the elastic and inelastic
scattering of 12C(p, p)12C and 12C(p, p’)12C in the vicinity of the resonance at 14.233 MeV [1]. The natural
width of this is 0.86 ±0.12 keV [2]. Yields of scattered protons were measured by a silicon surface-barrier
detector which was set at a laboratory angle of 160° in a scattering chamber. The scattered proton energies
were 10.28 MeV for the grand state and 6.35 MeV for the 1st excited state. The targets used were self
supporting carbon foils. For the first experimental room, the thickness was 15 µg/cm2. The proton energy
loss at 14.233 MeV was estimated to be 0.48 keV. For the second experimental room, a 6 µg/cm2 thickcarbon foil was prepared. The proton energy loss was estimated to be 0.18 keV. The openings in the image
and object slit of the analyzing magnet were decreased to 0.5 ±0.05mm. The design values of the radius ofcurvature and the dispersion are ρ=1280 mm and D=3.8, respectively. The resolving power of the beam
analyzing magnet is 9.4×103. The energy resolution is calculated to be 1.5 keV.
The measured yield curves are shown in Fig.1. Table 1 shows the experimental results. The protonenergy was varied by changing the field of the analyzing magnet in steps of 0.1 Gauss. The calculated
magnetic field is 4276.14 Gauss for the resonance energy of 14.233 MeV. For the first experimental room,
the width of the yield curve was estimated to be 1.7 keV. This value is in agreement with a calculated
width of 1.8 keV including the natural width, the energy loss in the target and the energy resolution of theanalyzing magnet. The experimental magnetic fields corresponding to the resonance energy of the first andsecond experimental room were estimated to be 4276.30 ±0.07 and 4276.70 ±0.07 Gauss, respectively.
The estimated error comes from an uncertainty of ± 0.05 Gauss in reading the resonance point on the yield
curve and an accuracy of ± 0.05 Gauss in the NMR Gauss meter. From above values, new radii ofcurvatures for the analyzing magnet have been estimated to be 127.99 and 127.98 mm for the first andsecond experimental room, respectively.

-5-

8000

10000

9000

7000
8000
12

6000

C 1st excited state

7000
12

C 1st excited state

5000

6000

5000

4000

4000

3000
12

12

3000

C ground state

C ground state

2000
2000

1000
4275.00

4276.00

4277.00

4278.00

1000
4275.00

4279.00

4276.00

4277.00

4278.00

4279.00

Analyzing Magnet [Gauss]

Analyzing Magnet [Gauss]

(a)

(b)

Fig.1

Yields of scattered protons from the elastic scattering

12

12

12

12

C(p, p) C and the inelastic scattering

C(p, p’) C. The data plotted in (a) is for the first experimental room. The data for the second

experimental room is shown in (b).
Table 1 Experimental results of energy calibrations since 1977.
Calculated value
1977 [3]1983 [4]2001 (this work)
First experimental room
Second experimental room

Magnetic field [Gauss]4276.144275.10 ±0.07
4278.1
4276.30 ±0.07
4276.70 ±0.07

Radius of curvature [cm]128.00128.03127.92

127.99127.98References[1] E. Huenges, H. Rosler and H. Vonach, Phys. Lett. B46 (1973) 361.
[2] Table of Isotopes 8th Edition, Vol.1 (1996) 13.
[3] K. Furuno et al., Calibration of the Beam Analyzing Magnet, UTTAC-2 (1977) 16.
[4] Y. Aoki, T. Komatsubara ; private communication.

-6-

1.3

Transmission of ions in 12UD Pelletron tandem accelerator for the
injection of negative single atomic ions and of negative molecular ions

K.Shima, T.Takahashi, S.Ishii, and K.Sasa
For the last several years, the transmission data of ions in 12UD Pelletron tandem accelerator have been
accumulated for the injection of negative single atomic ions as well as of negative molecular ions over the wide
range of ion species, ion energies and stripper foil thickness. As the result, some systematic trends oftransmission have been revealed.
1. Definition
By referring to Fig.1 showing the beam transportation system of 12UD Pelletron tandem accelerator, twotransmissions Tr(tank) and Tr(FC5) are defined.
[a] Tr(tank): the ratio of the number of atoms transmitting a tank to the number of atoms before injection into
tank, which is expressed by Tr(tank) = IFC3/qb/IFC2 . Here, IFC3 and IFC2 are respectively ion beam currents at
Faraday cup 3 and Faraday cup 2, and qb means the mean charge of ions colliding with stripper installed at
the terminal.
[b] Tr(FC5): the ratio of number of atoms summed over all charge states, q, observed at the Faraday cup 5(FC5)placed at the downstream of analyzing magnet to the number of atoms before injection into tank. Tr(FC5) is
given as Σq{IFC5(q)/q}/ IFC2 , where IFC5(q) is the beam current of ions with charge state q at FC5.
Two quantities Tr(tank) and Tr(FC5) are each other related by,
Tr(FC5) = Tr(tank) f(FC3/FC5),(1)
where f(FC3/FC5) indicates the transportation efficiency of ions from FC3 to FC5.
2. Transmission[a] Terminal voltage VT and carbon stripper thickness dependence
As was described in detail in ref. [1], Tr(tank) values are higher for increasing VT values and for decreasing
thickness of carbon stripper down to 2 µg/cm2 except for the acceleration of light ions such as H, He ions. As
an example, Tr(tank) values of 19F ions are shown in Fig.2 for VT = 10 MV and 3.5MV.
[b] Tr(tank) and Tr(FC5)
Generally, the 12UD tandem accelerator is operated by keeping the object slit width tobe 2mm 2mm, and the imaging slit width to be 2mm. After passing through these two slits, ion beams arecollected at the FC5, and Tr(FC5) values are measured. Fig.3 shows the observed values of Tr(tank) and Tr(FC5)
Tr(FC5) for light ions suchversus atomic number of projectiles, Z, when VT=10MV . Generally, Tr(tank)as H and Li, whereas the ratio Tr(FC5)/ Tr(tank) decreases with heavier or lower velocity ions and with thicker
stripper foils. This is the result of beam broadening due to the multiple scattering and energy straggling occurredat the collision with charge stripper.
[c] Single atomic ion injection and molecular ion injection into tankIn the acceleration of ions by using a tandem accelerator, some atoms have to be injected into a tank in theform of negative molecular ions because of the electron affinity is small or zero. In Table 1, observed values ofTr(tank) or Tr(FC5) for 16O and 28Si ions are listed for the injection of O- and Si- ions at VT=5MV, and O2- and Si2ions at VT=10MV. It is intended to compare the transmission of O- and O2- (and of Si- and Si2-) under thecondition that they collide with a charge stripper at the same velocity. Table shows that the Tr(tank) or Tr(FC5)values of atoms for the injection of molecular ions are smaller than those for the injection of atomic ions. This is





-7-

because the coulomb explosion of molecular ions during the collision with charge stripping atoms causes anadditional disturbance of projectile momentum both in forward and perpendicular directions of beams, and hence
the transmission of ions decreases. In fact, if we observe the Si ion beam profile at an imaging slit (see Fig.1) bychanging the slit width in the above mentioned collisions, the intensity distribution of Si ions originated from Si2is seen to be broader than that originated from Si-, which is drawn in Fig.4.
Transmission data for the incidence of negative molecular ions have been accumulated over the wide
range of ion species. As the result, an empirical formulae for Tr(FC5) has been evaluated by using the similar
procedure described previously [2].
Table 1. Transmission of ions for the injection of 16O- and 16O2-, and 28Si- and 28Si2-.
16
28
O ions
Si ions
Injected Terminal Tr(tank) Tr(FC5) Injected Terminal Tr(tank) Tr(FC5)ion
VT(MV)
ion
VT(MV)
16 28 O
5
78 %
28 %
Si
5
68 %
18 %
16 28
O2
10
50 %
16 %
Si210
41 %
9%

3. Beam currents on target
The beam currents, Iq(E), of ions having charge q and energy E at the target position, can be written as,
Iq(E) = IFC2 qF(q) Tr(FC5) f(transportation),(2)
where IFC2 is the beam current at FC2 placed at the upstream of the tank, F(q) means the charge fraction of ions at
the terminal colliding with the charge stripper, and f(transportation) means the transportation efficiency of ions
between FC5 and the target position. As mentioned above, Tr(FC5) is empirically known and the data of IFC2
have been accumulated over the wide range of Z for single atomic ions as well as molecular ions. F(q) is also
well established values when the charge states are equilibrium. Hence, by using these quantities, it is possible toestimate the beam current at the target position within a factor 2 for the incidence of single atomic ions and afactor 3 for the incidence of molecular ions, once Z, mass number, q and E of accelerated ions are given.
References[1] K.Shima, S.Ishii, T.Takahashi and I.Sugai, Nucl. Instrum. Methods A460 (2001)233.
[2] T.Takahashi, K.Shima, T.Ishihara and M.Yamanouchi, UTTAC Annual Rep. 1987, p.8.

119F ion, VT=10M V
0.9

19F ion, VT=3.5 MV

Tr(tank) = I(FC3)/qb/I(FC2)

0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0

5

10

15

20

25

Carbon stripper thickness (ug/cm2)

Fig.1. Transportation system of ions in 12UD
Pelletron tandem accelerator.

Fig.2. Transmission, Tr(tank), of 19F ions versus
stripper foil thickness at the terminal voltage VT=10
MV and 3.5 MV.

-8-Beam intensity at each distance (relative)

25

120
Tr(tank)

Tr(tank), Tr(FC5)

(%)

100

Tr(FC5)

80

60

40

Si beam profile at imazing
slit, Si- injection, VT=5MV
20
Si beam profile at imazing
slit, Si2- injection,
VT=10MV

15

10

5

20

0
0

0
0

20

40

60

80

100

2

4

6

8

Distance from the center of slit (mm)Atomic number of ion , Z

Fig.3. Transmissions Tr(tank) and Tr(FC5) plotted as afunction of Z (atomic number of accelerated ions).
The terminal voltage VT=10 MV for all ions.

-9-Fig.4. Beam intensity distribution of Si ions observedat the imaging slit for the incidence of Si- and Si2colliding with a charge stripping foil at the same velocity(VT=5 MV for Si- and VT =10 MV for Si2- ).

1.4

Microprobe system for hydrogen analysis of mineral samples

K. Sasa, Y. Yamato, H. Oshima, T. Komatsubara and K. Furuno.
[1] Construction of the microbeam line.
The construction of the microprobe system has been continued during the last year. The design was
described in the annual report 2000 [1]. Fig.1 shows the present layout of the beam line. The total lengthof this system is 14.25 m between the first slit and the target. The working distance from the exit of the
focusing lens to the target is chosen to be 0.33 m. In microbeam experiments, the opening of the image slit
is decreased to 1.0 mm. The beam is collimated with the double slit consisting of the first and second slit.
The diameters of the first and second slit are 0.4 mm and 2.0 mm, respectively. The third slit is placed in
front of the Russian quadruplet. The diameter of the third slit is 9.0 mm. The chamber slit is placed on theexit of the Russian quadruplet. The diameter of the chamber slit is 4.2 mm. Fig.2 shows a photograph ofthe main part of the microbeam line.
The geometrical axis of the four quadrupole magnets in the Russian quadruplet is adjusted to becoaxial each other within 50 µm. The output of the power supplies for the Russian quadruplet is controlled
by a 16bit DAC module to obtain the resolution of output currents as small as 0.5 mA.
6465

2400

14250
2300

530

330

1140

ST8 ST9

Analyzing
MagnetImage
Slit

TargetST7
QS
ST6
Switching First
Magnetic Quadrupole Magnet Slit
MagnetSteerer

Wall
1500

First Target RoomAnalyzer Magnet Room

Fig.1

Present layout of the microbeam system.

3rd S lit

Fig.2

3rd Russian
Slit Quadruplet

2nd
Slit

Russi an Q uadruple t

Ta rget Chamber

A photograph of the main part of the microbeam line.

- 10 -

ChamberSlitFig.3The computer screen of the control console.

[2] Control system.
Power supplies for quadrupole magnets and steering magnets are controlled by means of a personal
computer. To make execution most efficient, the control program is developed with Visual C++ operated
on Windows 2000. Fig.3 shows the computer screen of the control console. When we change opticalparameters, we select an optical element on the computer screen using a mouse click. The output of thepower supply can be adjusted manually by turning the mouse wheel. Suitable transport parameters can berecorded in the computer. The recorded transport parameters can be read out and reset the suitable values
within about 30 seconds automatically. Beams can be well focused by the parameters reproduced with thisautomatic setting. We can observe pictures from a CCD camera on the computer screen also.
[3] Microbeam formation.
The beam is finally focused on the target by means of the Russian quadruplet [2]. Beam optical
calculations were carried out with the computer program TRACE-3D [3]. A demagnification of 16.7 canbe expected for this microprobe system. The diameter of the focused beam spot is expected to be 24 µm.
In the year of 2001, several tentative experiments were performed to estimate the size of microbeam spots.
We focussed an 18 MeV proton beam on an Al coated quartz plate as thick as 2 mm. The projected rangeof 18 MeV proton is 1.85 mm in the quartz, so that all protons were stopped in the quartz. The focused
beam spot was observed with a microscope set just behind the quartz target. The microscope had a CCD
camera with 660×480 channels. Fig.4 shows a focused beam spot area. The beam spot is measured to be
72 µm in diameter. The beam current is 0.5 nA.
Table 1 shows a comparison of calculated exciting currents of the Russian quadruplet withexperimental currents. The outer and the inner quadrupole magnets of the Russian quadruplet have thesame exciting currents for each combination. The relative errors between the calculated and experimental
exciting current of RQ 1 – 4 and RQ 2 – 3 are 3.6 % and 2.7 %, respectively.

- 11 -

72 µm

72 µm

Fig.4

A focused beam spot for the 18 MeV proton beam. The beam current is 0.5 nA.

Table 1 A comparison between the calculated and the experimental exciting current for the 18 MeV
proton beam.



Calculated magnetic field [kG /cm] Calculated exciting current [A]

RQ 1 - 4
RQ 2 - 3

0.4425-1.0609

Experimental exciting current [A]

3.404
8.161

3.526
8.385

[4] Beam transmission
A test of the beam transmission was performed for proton and 19F5+ beams. There are five slits fromthe image slit of the beam analyzing magnet to the target camber slit on the microbeam line (Fig.5). The
aperture of the first slit is 0.4 mm in diameter. FC5 is set just after the image slit of the beam analyzing
magnet. FC6 is placed between the first and the second slit. FC7 is placed behind the second slit. The
experimental results are summarized in Table 2.
The beam transmission from FC5 to the target is about 2 %. The beam current of this microprobe
system would be sufficient to perform hydrogen analysis of mineral samples.
Slit1
Ion Source
Slit2

FC1
FC2

TandemFC3
Object Slit
First Slit

FC4

2nd Slit

3rd Slit

Chamber Slit
FC-Target

Image Slit

FC5

SW

ST7
FC6

Fig.5

ST8 ST9RQ

FC7

A schematic setting of the Faraday cups (FC) for the measurement of beam current.

- 12 -

Table 2 Experimental results of the beam transmission for proton and 19F5+ beams.
Beam current [nA]
15 5+
F [30 MeV]
P [20 MeV]
P [18 MeV]

FC2
150
300
132

FC5
90
120
25

FC6
5.8
5.0
0.62

FC7
0.5
2.0
0.54

FC-target
0.48

Acknowledgement
This work is supported in part by the Grand-in-Aid for Scientific Research (A) of the Ministry of
Education, Science, Sports and Culture.
References[1] K. Sasa et al., UTTAC-69 (2000) 5.
[2] A. D. Dymnikov, T. Ya. Fishkova and S. Ya Yavor, Sov. Phys. Tech. Phys. 10 (1965) 340.
[3] K. Crandall and D. Rusthoi, “TRACE-3D Documentation”, third edition,
Los Alamos National Laboratory Report LA-UR-97-886(1997).

- 13 -

1.5

Solution for the pulse height defect of MSTPC

H. Ishiyama1, T. Kawamura2, T. Hashimoto2,3, T. Ishikawa2, T. Furukawa4, M. H. Tanaka1, N. Yoshikawa1,
H. Miyatake1, S. C. Jeong1, T. Nomura1, T. Komatsubara and Y. Tagishi
Rate dependencies of the pulse height from the KEK gas chamber called “ Multi-Sampling and Tracking
Proportional Counter (MSTPC) [1] have been measured with the 14N-beam (E = 30 MeV) from theTandem accelerator. Possible solutions for the pulse height shifts observed in the MSTPC are discussed.
roof plate2
beam

0.53kcps
3.2kcps10.0kcps

1.5

200mm
gating grid1
shield grid
35

ground grid

6
5

anode wire

0.5

cathode PAD cell(total 24 cells)

0

0

11

Fig. 1 Schematic Cross-sectional view of the MSTPC.

5

10
15
PAD number

20

25

Fig. 2 Peak shifts of the MSTPC.

Fig. 1 shows the cross-sectional view of the MSTPC. The MSTPC can measure a three-dimensional
track of a charged particle and the energy loss along its trajectory. Electrons produced by the incoming
charged particle in the drift space are drifted through the three type grids toward the proportional region,
which consists of 24 cathode PAD cells with anode wires. The gas inside the MSTPC (90% He and 10%CO2) works both as a counter gas and a gas target. Using the MSTPC, an experimental program todetermine astrophysical reaction rates for (α, n) with light neutron-rich radioactive nuclear beams is inprogress.
The large peak shift of the energy loss signals from each PAD was observed under high injection rates(< 104 pps) of low-energy heavy ions. Fig. 2 shows the systematic change of the peak shift for various
injection rates of 15N particles (E = 2 MeV/u). The horizontal axis shows the PAD number, whichcorresponds to the distance in unit of cm from the beam injection point. The pulse height is normalized by
one obtained under the injection rate about 200 pps. The sudden change of pulse heights around bothedges of the MSTPC was found to be a charge-up on the G10 frames of the girds. In order to avoid this1

High Energy Accelerator Research Organization, Oho1-1, Tsukuba-shi, 305-0801 Japan.
Tokyo University of Science, Yamazaki 2641, Noda-shi, Chiba-ken, 278-8510 Japan.
3
Research Fellow of the Japan Society for the Promotion of Science.
4
Osaka University, 1-1 Machikaneyama, Toyonaka-city, Osaka, 560-0043, Japan.
2- 14 -

charge-up effect, we covered these frames by metal plates.
The pulse height defect around the center of the MSTPC is supposed to come from the space charge
gain limitation near the anode wire. As a solution, we have therefore installed a gating grid [2] as shown in
Fig. 1. Alternate wires of the gating grid are connected two separate voltage sources and the transparencyof the gating grid plane is controlled by changing the potential difference of alternate wires. The gating
grid plane is normally kept opaque so that electrons do not reach anode wires. When an external trigger,
for example, generated by neutron counters in the case of our experiment, signals a nuclear reaction event,
the gating grid makes transparent for the time so that the drift electrons reach anode wires. With these
possible improvements, we tested effects of the gating grid experimentally using a sample beam 14N.
The 14N-beam (E = 30 MeV) was provided by Pelletron 12UD. The 14N particles elastically scatteredfrom a thin Au-target were transported to the MSTPC by a QDQ spectrometer. The gating grid was
triggered by signals from a SSD at the end of the MSTPC. The trigger rate was reduced by a down scalar.
Fig. 3 shows peak shifts of the output signals versus counting rates without the gating grid. The verticalaxis shows the pulse height normalized by one when the injection rate is a few pps. The horizontal axis
shows the PAD number. The sudden change of the peak shift is clearly disappeared and the shift is sosmooth in contract to fig. 2. When the injection rate is 3.6 kpps, the pulse height defect becomes about
15% around the center of MSTPC. This value is nearly the same to the case of 15N-beam.

1.3

2
0.5kcps
2.6kcps
3.6kcps

1.5

0.02kcps
0.3 kcps
2.6 kcps
5.6 kcps

1.2
1.1
1

1

0.9
0.5
0.8
0

0.7
0

5

10
15
PAD number

20

25

0

Fig.3. Peak shifts without the gating grid.







5

10
15
PAD number

20

25

Fig. 4. Peak shifts using the gating gridFig.4 shows peak shifts using the gating grid. The trigger rate of the gating grid was fixed to be 20 cps
for various injection rates. This value is a realistic one when our measurements of (α, n) reaction crosssections is performed. The peak shifts are suppressed within 2% up to the 5.6 kpps injection rate. Thisvalue is small enough to detect nuclear reactions of our interest.
As mentioned above, an origin of the pulse height defect around the center of the MSTPC is supposed tobe the space charge gain limitation at the anode wire due to numerous ions generated by the proportional- 15 -

multiplication process. The growth in the avalanche process of a positive ion sheath around the anode wirecauses the local reduction of the electric field to reduce the proportional multiplication. Following theformulation of the space charge limitation by Hendricks[3], we can evaluate the pulse height shift. The
estimated value of the pulse height defect becomes 9% when the injection rate is 3.6 kcps. This value isconsistent with the measured value. But the rather small reduction of the pulse height defect around bothedges of the MSTPC can not be explained by the space charge gain limitation. A further investigation istherefore needed.
References[1] Y. Mizoi, et. al., Nucl. Instrum. A 431(1999)112.
[2] P. Nemethy, et. al., Nucl. Instrum. Meth. A 212(1983)73.
[3] R. W. Hendricks, Rev. Sci. Instrum. 40(1969)1216.

- 16 -

1.6

Effect of minimum strength of mirror magnetic field on production ofhighly charged ions from RIKEN liquid He free super conducting
Electron Cyclotron Resonance Ion Source (RAMSES)

H. Arai, M. Imanaka, T. Nakagawa1, I. Arai and S.M. Lee

We have newly constructed two superconducting electron cyclotron resonance ion sources (ECRISs),
which are 18GHz ECRIS (RAMSES) at RIKEN [1] and 14GHz ECRIS (SHIVA) at our laboratory [1-3].
From these sources, intense beams of highly charged heavy ions were successfully extracted. Typicalresults are 5eµA of Kr27+ and 2eµA of Kr29+ from RAMSES[1] and 10eµA of Xe30+ and 1eµA of Xe36+
from SHIVA[1-3].
Recently, it was reported that the optimum value for minimum strength of mirror magnetic field (Bmin)
exists to maximize the beam intensity of Xe20+ produced from ECRIS at Laboratorio Nazionale Sud,
Catania (SERSE) [4]. However, the effect of Bmin on the beam intensity of various charge states is still
unclear. To clarify this effect and to optimize the magnetic configuration to maximize the beam intensityof various charge state heavy ions extracted from ECRIS, we need further investigation. Especially, it isimportant to measure the beam intensity of various heavy ions systematically as a function of magnetic
field. From this point of view, we measured the beam intensity of various heavy ions as a function of Bmin.
We used RAMSES at RIKEN for this experiments. Fig. 1 shows a cross-sectional view of RAMSES.
For studying effect of Bmin on the beam intensity, we changed Bmin from 0.25T to 0.6 T without changing
the maximum magnetic field strengths on both the beam extraction side and the microwave injection side
(Bext and Binj), respectivety as shown in Fig.2. In this experiment, Bext and Binj were fixed at 1.13 and 1.7 T,
respectively. The injected microwave power was 500 W. The extraction voltage was 12 kV. The gaspressure, position and negative voltage of biased electrode were changed to maximize the beam intensity.
We did not use the gas mixing method for simplicity the experiment.


To determine the optimum Bmin for various ions, we measured beam intensities of O5,6+ and Ar711+

ions as function of Bmin. Fig. 3 shows the beam intensity of Ar7+ and Ar11+ as a function of Bmin. In case ofboth Ar7+ and Ar11+, the beam intensity gradually increased with increasing Bmin up to 0.45T and thengradually decreased. Furthermore, we measured that the optimum Bmin for maximizing the beam intensity
in case of the other ions were almost the same as the value 0.45T in case of Ar7+ and Ar11+.
References[1] T. Nakagawa et. al., Rev. Sci. Instrum., 73 (2002) 513.
[2] T. Kurita et. al., Nucl. Instrum. Methds B (to be published).
[3] T. Kurita et. al., UTTAC Annual Report 2000, Tandem Accelerator Center, University of Tsukuba.
[4] D. Hitz, et. al., Rev. Sci. Instrum. 73 (2002) 509.

1

The Institute of Physical and Chemical Research (RIKEN)- 17 -

G-M refrigerators

First Stage

High-Tc current
lead

Second stage
40 K shield

Plasma chamber
Hexapole magnet

Negative bias disc
Electrode
Einzel lens
18 GHzMicrowave

Gas inlet

TMP(150 l/s)
TMP(500 l/s)
Beam extraction Solenoid coils IV III
side

II I

Microwave injection
side

1m

Fig.1 Cross sectional view of RAMSES

Microwave
Injection side

Beam Extractionside

Fig.2 Magnetic configuration of RAMSESBeam Intensity (µA)




Ar7+





Ar11+



0.1

0.2

0.3

0.4

0.5

0.6

Bmin (T)Fig.3 Measured beam intensities of Ar7+ and Ar11+ as a function of Bmin;
Bext and Binj were fixed at1.13 and 1.7 T, respectively.

- 18 -

1.7

Radiation safety at tandem accelerator center

T. Komatsubara, K. Shima, K. Sasa, T. Katabuchi, Y. Yamato, S. Ishii, T. Takahashi, H. Kimura,
H. Oshima, Y. Tajima, and K. Furuno

In the new Japanese regulation in accordance with ICRP90 recommendation, the annual eﬀective dose limit has been decreased. For the safety of radiation control at the Tandem Accelerator
Center, a new evaluation of eﬀective dose by gamma and neutron radiations has been done.
Neutron dose rates were measured by a BF3 neutron dose survey meter ALNOR 2202D. The
tube of the BF3 proportional counter is surrounded by a shield made of polyethylene and boron
plastics in order to degrade fast neutrons. The survey meter indicates eﬀective dose and also
provides pulse signals for counting integration measurements. The survey meter is calibrated byusing 241 Am+Be neutron source of 357MBq in which intensity of emitting neutron is 2.7×104[n/sec]. Corresponding neutron dose is calculated to be 0.32 [µSv/h] at 1[m] from the source
by using the eﬀective dose coeﬃcient Γ = 1.19 × 10−5[µSv/h·m2 /(n/sec)]1). The results of thecalibration are shown in Table 1 depending on the direction for the survey meter.
Gamma rays were measured by an ionization chamber survey meter Aloka IC-311. The resultsof the calibration are shown in Table 2 by using 137 Cs source of 371.4 kBq. The eﬀective dose
coeﬃcient of Γ = 0.0779 [µSv/h/MBq·m2 ] 1) is used.
As the results of the measurements which were brieﬂy reported in reference 2, Table 3 shows
measured dose rates for the 1MV tandetron and Table 4 for the 12UD pelletron. For the 1MV
tandetron, proton beam was accelerated up to 1.6 MeV by 0.8 MV terminal voltage. Beamcurrent was 0.1 µA irradiated on a thick tantalum beam stopper. No radiation exceeding background has been measured at any position in the tandetron experimental room. For the 12UD
pelletron accelerator, the radiation measurement has been done by using proton beam accelerated
up to 22 MeV by 11 MV terminal voltage. The ion beam was irradiated on a beam stopper ofthick tantalum plate located in the counting room shown in ﬁgure 1. Neutron eﬀective dosewere measured with beam of 0.45 and 0.7 µA, in the target room and outside of shielding wall,
respectively. Small ﬂux of neutrons through the concrete shielding wall have been measured asshown in Table 4. By normalizing beam intensity and distance from the irradiation point, theeﬀective dose penetration rate can be determined to be 3.1 × 10−6 for the 1.2 m thick normal
concrete of 2.3 g/cm3 density.
In the new evaluation of radiation dose, eﬀective dose by neutrons and gammas has been
calculated. For operation of the 12UD tandem accelerator we assume that thick tantalum targets
at the 2nd target room and in the vacuum chamber of analyzing magnet are irradiated by 3 µA
and 1.5 µA, respectively. Reaction cross sections are calculated as a function of incident beamenergy by using CASCADE program. Eﬀective thickness of the tantalum stopper is estimated byconsidering stopping power3) . Since neutron energy spectrum is similar to those for 241 Am+Be
neutron source, penetration factors1) for neutron of the 241 Am+Be neutron source are used toevaluate eﬀective dose. Since the calculated dose is over estimated for 1.2m concrete shield, we
introduce correction factor Gn = 0.023 from a comparison between the calculation and the neutron
measurements. For the 1MV tandetron, we assume that the accelerator is under operation of
1MV with 3µA beam. The only X-rays from stray electrons are important. Furthermore, several
radioactive source are assumed to be stored in a storage room. As the results of the calculation,
estimated eﬀective dose are shown in Table 5. Working hours and accelerator operation are
estimated to be 40h/week and 144h/week. The 3 months correspond to 13 weeks. The eﬀective
dose are lower than the limitation of the new Japanese regulation for all calculated points.
In Table 6, 7 and 8, eﬀective dose measurement by area monitoring system are shown for thisﬁscal year. The measured results on border of control area are small enough which should be- 19 -

lower than the regulated limit of 1300µSv/3months.
Since an eﬀective dose can be proportional to a beam intensity and operation hours, productsof beam intensities and beam hours are evaluated for the 12UD tandem accelerator as shownin Table 9. Under our regulation the beam intensity is limited to be 3µA and operation hours
should be less than 144hours/week. When we multiply the regulated value a limit of the productis introduced to be 1728 [µA·h] for a month. For every month, the product is much smaller thanthe limitation.

Reference
1) Practical manual of shielding calculations for radioisotope facility, 2000, Nuclear Safety Technology Center, Hakusan 5-1-3-101, Bunkyo-ku, Tokyo, Japan2) T. Komatsubara, K. Shima, K. Sasa, T. Katabuchi, Y. Yamato, S. Ishii, T. Takahashi, H.
Kimura, H. Oshima, Y. Tajima, K. Furuno, PROGRESS REPORT, INDC(JPN)-189/U, JAERI,
Tokai, (2002), p89-91, “private communication”
3) Program SRIM (2000) J.F. Ziegler, IBM-Research

ALNOR 2202D
distance
[mm]
200
250
300
coeﬃcient

241

Am+Be
calculation[µSv/h]
8.0
5.1
3.6

θ=0
[µSv/h]
10
5
3
1.0

θ=90
[µSv/h]
6
3
2
1.6

θ=0
pulse [cpm]
203
125
83
0.69 ×10−3[µSv/pulse]

θ=90pulse [cpm]
130
88
68
0.95 ×10−3[µSv/pulse]

Table 1 Result of calibrations for BF3 neutron dose
survey meter, ALNOR 2202D. θ indicates angle of source position with respect to symmetry
axis of the survey meter.

Aloka IC-311
distance
[mm]
100
150
200
Back ground
coeﬃcient137

Cscalculation[µSv/h]
2.9
1.3
0.7

measure[µSv/h]
3.7
1.7
1.2
0.2
0.81

Table 2 Result of calibrations for gamma survey meterof ionization chamber, Aloka IC-311- 20 -

location

distance

beam current

scattering chamberswitching magnet
control desk
entrance

[m]
0.3
3.3
8.0
5.2

[µA]
0.1
0.1
0.1
0.1

gamma
IC-311[µSv/h]0000neutron
ALNOR 2202D[µSv/h]0000neutronpulse
0/4min0/4min0/4min0/4minTable 3 Gamma and Neutron dose rates during theion beam experiment of the 1 MV tandetron

location

distance

beam current

Target room
Outside of wall

[m]
8.0
8.6

[µA]
0.45
0.7

gamma
IC-311[µSv/h]200
0neutron
ALNOR 2202D[µSv/h]9600
0.04

neutronpulse[cpm]
30/30minTable 4 Gamma and Neutron dose rates during theion beam experiment of the 12 UD tandem accelerator

location
The 2nd experimental room
Tandetron experimental room
Entrance of storage room
Northern border of control area
Entrance of the 1st experimental room
Entrance of tandetrom experimental room
Western border of university of Tsukuba

eﬀective dose
0.09 [µSv/week]
0.02 [µSv/week]
0.54 [µSv/week]
73 [µSv/3months]
22 [µSv/3months]
3.6 [µSv/3months]
5.8 [µSv/3months]

Table 5 Sum of calculated eﬀective dose by accelerator operations of the
12UD tandem and the 1M tandetron and the storage of several RI sources.

April
May
June
July
AugustSeptember
OctoberNovember
DecemberJanuary
February
March

A1
0
0
27
26
1000
36
2
0
0
0
97
7475

A2
0
0
22
0
296
7260
62
284
3490
191
483
0

A3
0
0
0
0
0
0
0
0
0
0
0
0

A4
0
0
0
0
0
0
0
0
0
0
0
0

A5
0
0
0
0
0
0
0
0
0
0
0
0

A6
0
0
0
0
0
0
0
0
0
0
0
0

Table 6 Gamma-ray and X-ray radiation exposures measured inside of thebuilding. The values are shown in units of µSv/month.

- 21 -

April
May
June
July
AugustSeptember
OctoberNovember
DecemberJanuary
February
March

N1
2
3
331
440
16330
298
109
79
34
29
840
81290

N2
10
41
884
0
5068
227
2843
93
40100
4115
16950
0

N3
0
0
0
0
0
0
0
0
0
0
0
0

N4
0
0
0
0
0
0
0
0
0
0
0
0

N5
0
0
0
0
0
0
0
0
0
0
0
0

N6
0
2
2
0
0
0
4
2
0
0
0
42

Table 7 Neutron radiation exposures measured inside of the building in unitsof µSv/month.

April
May
June
July
AugustSeptember
OctoberNovember
DecemberJanuary
February
March

NP1
0
0
0
0
5
0
0
0
0
0
0
0

NP2
0
0
0
0
0
0
0
0
0
0
0
0

NP3
0
0
0
0
0
0
0
0
0
0
0
0

Table 8 Neutron radiation exposures measured outside of the building on theborder line of control area. The values are shown in units of µSv/month.

- 22 -

April
May
June
July
AugustSeptember
OctoberNovember
DecemberJanuary
February
March

Beam current × Operation hours[µ A ·h]
0
5.6
8.6
3.3
11.3
6.5
2.8
2.7
33.0
3.2
7.3
33.2

Table 9 Beam current multiplied by operation hours [µA·h] for the accelerator
operation of 12UD tandem accelerator.

Figure 1. Location of a radiation target and detection
positions for the 12UD pelletron experiment.

- 23 -

2.1

Elastic and inelastic scattering protons on nat Si at 28Si(p, n) thresholdenergy region

N.Okumura, T.Joh and Y.aoki
Last year, we reported that the energy dependence of proton total reaction cross sections on 28 Si had
resonance like behavior around the 28 Si(p, n) threshold energy (15.7 MeV) [1]. The depth and width of the
dip are about 60 mb and 300 keV, respectively. The width corresponds to 2 × 10−21 sec. The presence of
this marked energy dependence may reveal a reaction mechanism of the proton elastic scattering, incident
proton may temporarily be captured by a target nucleus, for instance. Partial wave analysis of the elastic
phase shift should be correlated to what orbital angular momentum is really related with this phenomenon.
Energy dependence of the phase shift should be related the time delay of the outgoing wave packet.
Austern showed the time delay Qαβ of the reaction (α , β ) is related with the energy derivative of thephase shift as,∂δQαβ = 2 h̄
,
(1)
∂ Eα
[3]. Hirota measured elastic data of 28 Si(p, p) reaction and analyzed by using an optical model approach[2]. We believe that the coupled channels effect may be important.
Differential cross sections (σ (θ )) and analyzing powers (Ay(θ )) of 28 Si(p, p) and (p, p) reaction were
measured by using polarized protons accelerated between 15.1 and 16.7 MeV. The silicon target was about
1.45 mg/cm2 thick SiO2 plate. Protons elastically scattered off the target were detected by two pairs of
3 mm thick solid state Li drift detectors located on either side of the beam line. These detectors subtended
solid angles of 0.3 to 1 msr. Proton polarization was monitored continuously by a polarimeter located45 cm downstream of the target position. Analyzer reaction is 4 He(p, p) elastic scattering to 112◦ .
Fig. 1 summarized the σ (θ )/σR (θ ) and Ay(θ ) of elastic scattering at some incident proton energies.
The inelastic scattering cross sections and analyzing powers leading to the 28 Si(2+)(Ex = 1.78 MeV) and28
Si(4+)(Ex = 4.6 MeV) of 15.9 MeV protons are shown in fig. 2. The phase shift analysis using thesedata is in progress.

References[1] N. Okumura, T. Joh, Y. Honkyu, K. S. Itoh and Y. Aoki, UTTAC annual report 21(2001).
[2] K. Hirota, K. Miura, K. Koyama, N. Okumura, K. Kishita, Y. Mukouhara, S. Nakagawa, M. Masaki,
Y.Tagishi and Y.Aoki, UTTAC annual report 13(1995)[3] Norman Austern, DIRECT NUCLEAR REACTION THEORIES, INTERSCIENCE MONOGRAPHS AND TEXTS IN PHYSICS AND ASTRONOMY, Vol. XXV, chap.1(1970).

- 24 -

1

10

8

0.5
6

10

15.9MeV

0

16.7MeV(x10 )
7

-0.5

10

6

10

5

16.4MeV(x105)-1
1

15.9MeV(x104)

0.5

315.7MeV(x10 )

-0.5
Ay(θ)

104

-1
1

15.5MeV(x102)

103

0.5
15.5MeV010215.3MeV(x10)-0.515.1MeV

10

1

10

0

-1
1
0.5
15.3MeV

0
-0.5
-1

-1

10

20

40

60

80 100 120
θc.m. [deg.]

140

160

20

180

40

60

80 100 120 140 160 180
θc.m. [deg.]

Fig. 1. Proton elastic cross sections and analyzing powers. The each line is shown for guide eyes.

Ay(θ)

σ(θ)

100

10

Ay(θ)

1
10
σ(θ)

σ(θ)/σR(θ)

15.7MeV

0

1

0.1
20

60 100 140 180
θc.m. [deg.]

0.6
0.4
0.2
0
-0.2
-0.4
0.6
0.4
0.2
0
-0.2
-0.4

28

Si(2+)

28+

Si(4 )

20

60 100 140 180
θc.m. [deg.]

Fig. 2. Inelastic scattering cross sections and analyzing powers of 15.9MeV protons.

- 25 -

2.2

CDCC analysis of triple differential cross section of 208 Pb(d,pn) reaction at Ed =56 MeV

Y. Aoki, N. Okumura, T. Jho and Y. Iseria
As an extension of an CDCC analysis, triple differential cross sections of deuteron elastic break upprocess is studied.
The concept of Continuum Discretized Coupled Channels (CDCC) approach of deuteron elastic scattering and breakup process is spelled out by Kawai and co-workers in ref. [1]. A brief description is given
here just to remind the concepts of the ingredients. The CDCC Hamiltonian may be written as follows,
H = Tp +Vp + Tn +Vn +Vpn ,where Tp and Tn are kinetic energy operator of a proton and a neutron, which are bound to form a deuteronin the incident channel. They interact with each other by the potential Vp−n . Continuum states are discretized by wave number binning. We assumed that the spin flip process may be negligible and thespin singlet states are neglected. Scattering states really taken into the analyses are, 3 S1 − 3 D1 , 3 D2,3 ,3P0,1 and 3 P2 − 3 F2 states. Wave number k p−n of the relative p-n motion are binned by 10 bins ofk p−n = 0 − 0.1 , · · · 0.9 − 1.0 f m−1. Reid soft core potential [2] is assumed whenever it is available.
Gaussian potential, which reproduce the phase shift, is assumed for the 3 D3 states.
Proton and a neutron interaction with a target nucleus are given by potentials of Vp and Vn . No explicit
excitation of target nucleus and rearrangement reactions are taken into account. Nucleon optical potential,
CH89 [3], of half the deuteron kinetic energy E p = En = Ed /2 are assumed in the present analyses. Protonin the deuteron interact with the target nucleus via Coulomb potential, which are assumed to be due touniformly charged sphere. Because deuteron is a bound state of proton and a neutron, antisymmetrization
correction is necessary even if we assume that the phenomenological optical potential takes care of theexchange effect of incident nucleon and nucleons in the target. This antisymmetrizaton correction is
phenomenologically taken into account by reducing(increasing) the real(imaginary) central part of the
optical potential.
Proton and neutron coordinates r p , rn are expressed by the center of mass and relative coordinates by
the following relation,
R = (rn + r p )/2,r = (rn − r p )Coupled channels equation for the R coordinates are written by partial wave expansion, solved numerically and S-matrices are obtained. In handling the nucleon spin-orbit potential, terms with (s p − sn ) areneglected.
A detailed data of elastic scattering by Matsuoka [4] and triple differential cross sections by Okamura[5] are taken into account and the case of 56 MeV deuteron + 208 Pb are considered.
Elastic differential cross section and other polarization observables are calculated from the elastic Smatrices. Differential cross section of experimental data and the present analysis are compared in fig.
1.

- 26 -

208

σ/σR

1.0E+0Pb(d,d) Ed= 56 MeV

1.0E-1

1.0E-2

1.0E-3
0

20

40

60

80

100

120

θCM (deg.)

Fig. 1 Comparison of elastic of 208 Pb(d,d) at Ed =56 MeV
A reasonable reproduction can be seen. This is also true for the polarization observables. Phase
relation, peaks and valleys of the angular distribution pattern, can be reproduced well by introducing theantisymmetrization correction.
d3σ
are calculated by the following relation,dΩn dΩ p dE p
d 3 σν p νn2π
2π µ p+n−T=|T f i |2 ρ1 (E p ) =|T |2 ρ p (E p ).
dΩn dΩ p dE p h̄v p+n−Th̄ Pp+n−T f i

Triple differential cross section(1)

Spin orientations of ν p and νn are included in this expression. Proton state density ρ p (E p ) are given in theliterature [6].
Expression of T-matrix (T f i ) is somewhat complicated because of the recoupling of p-n state wave
functions and many angular momenta involved in the analysis and is not written here.
Triple differential cross sections measured by Okamura is a proton energy spectrum measured at θ p =θn = 0◦ . At very forward angles, many partial waves interfere constructively and make a very sharp
peak. Average over the proton and neutron detectors should be made to explain the experimental energy
spectrum.

- 27 -

500

d3σ/dEp,dΩp,dΩn(mb/MeVsr2)

450

µI=±1

208

400

Pb(d,pn)350

unpol. d

Ed= 56 MeV

300

µI=0

250
200
150
100
50
0
10

15

20

25

30

35

40

45

50

Ep (MeV)Fig. 2 Comparison of experimental and CDCC triple differential cross sections at θn = θ p = 0◦
Fig. 2 compares the experimental data with the averaged triple differential cross sections for polarized
and unpolarized deuterons. Polarization axis is along the beam direction.
One can see a large peak at E p = 30 MeV, while experimental peak is located at about E p = 31-32 MeV.
Large valleys can be seen on both sides of the peak, which are not seen in the experimental data. The originof these valleys can be ascribed to the destructive interference of nuclear and Coulomb contributions forthis reaction. This statement can be confirmed by limiting the maximum angular momentum and drawing
an energy spectrum.
Importance of continuum coupling can also be confirmed as follows.
43

Coul. int. matrix elements
k=0.1 -- 0.2 (1/fm)

2

d(S) <=>3D2

arb. unit

1d(S) <=>3P1

0
-1

3

3

P1<=> D2

-2
-3
-4
0

5

10

15

20

25
R (fm)

30

35

Fig. 3 Typical Coulomb matrix elements- 28 -

40

45

50

Fig. 3 compares three matrix elements, which connect three states in p-n system,the S-state of thedeuteron, 3 P1 and 3 D2 . Wave number of these scattering states are k p−n = 0.1 − 0.2 f m−1. Continuumcontinuum coupling, in this case, is much larger than the direct break up matrix elements. We can study
the elastic break-up cross section by plotting the following quantity,
10 π(2 J + 1)|SJ (break − upchannel)|22
3 Kp+nBy using this quantity, we can compare quantitatively at what J and to what breakup channel, the incident
flux is actually directed. Ratio of positive to negative parity break up can be studied by changing theamplitudes of these off diagonal matrix elements.
References
1 M. Kamimura, M. Yahiro, Y. Iseri, Y. Sakuragi, H. Kameyama and M. Kawai, Prog. Theor. Phys. 89
1986
2 R.V. Reid, Jr., Ann. Phys.50(1968) 411
3 R.L. Varner, W.J. Thompson, T.L. McAbee, E.J. Ludwig and T.B. Clegg, Phys. Rep. 201(1991) 59
4 N.Matsuoka, H.Sakai, T. Saito, K. Hosono, M. Kondo, H. Ito, K. Hatanaka, T. Ichihara, A. Okihana,
K. Imai, K. Nishimura, Nucl. Phys. A455 (1986) 413
5 H.Okamura, A.Ishida, N. Sakamoto, O.Otsu, T. Uesaka, T. Wakasa, H. Sakai, T. Niizeki, H. Toyokawa,Y. Tajima, H. Ohnuma, M. Yosoi, K. Hatanaka and T. Ichihara, Phys. Rev. C58 (1998) 2180
6 G.G. Ohlsen, Nucl. Instr. Meth. 37(1965) 240.

- 29 -

&
Analyzing powers for the 6Li ( d , p ) 7Li reaction at an incident energy of
90keV

2.3

N.Yoshimaru, T.Iiduka and Y.Tagishi&

In order to obtain the information of the reaction mechanism of 6Li (d , p ) 7Li reaction at low energy
region, we measured analyzing powers of this reaction at incident deuteron energy of 90keV. The 6Li target is&the same as that used in the 6Li (d , α ) 4He reaction described in this annual report. The emitted particles weredetected by four silicon photodiodes (HAMAMATSU S3204). Four analyzing powers, iT11, T20, T21 and T22,
were measured for laboratory angles from 0- to 105-degree with 15-degree step. A typical energy spectrum isshown in Fig.1, where the number 1, 2, 3, and 4 arecorresponding to the emitted particles from reactions&

H (d , p ) 3H,

6&

Li (d , p1 ) 7Li,&&
Li (d , α ) 4He, respectively. The measured analyzing

6

1

1000

Li (d , p0 ) 7Li and643
counts2100

2

powers are shown in Fig.2. An interesting thing is that10

the vector analyzing power has negative values of&around –0.1, although those for 6Li (d , α ) 4He are zero

1
0

200

400
channelwithin the statistical errors as described in this annual
report. A further analysis is now in progress.

600

Fig.1 Energy spectrum of the emitted particles.

i T1 1

T2 0

0.5

0.5

0.3

0.3

0.1

0.1

-0.1

-0.1

-0.3

-0.3

-0.5

-0.5

0

50

100

0

0.5

0.5

0.3

0.3

0.1

0.1

-0.1

-0.1

-0.3

-0.3

-0.5

-0.5
50

100

T2 2

T 21

0

50

0

100

θc.m. (degree)
Fig.2 Analyzing powers iT11, T20, T21 and T22.

- 30 -

50

100

800

Measurement of proton polarization in 208 Pb(d,p)209 Pb
reaction at incident energy of 20 MeV

2.4

M.Yamaguchi, N.Kawachi, T.Iizuka, N.Yoshimaru, K.Shiga and Y.Tagishi+

The polarization of emitted protons from the 208 Pb(d,p)209 Pb reaction to the 92 ground-state
was measured by a high eﬃciency proton-polarimeter[1]. The experiment was performed at theTandem Accelerator Center, University of Tsukuba (UTTAC). The incident deuteron energy was
20.5 MeV. The target was a self supporting 208 Pb foil with a thickness of 40 mg/cm2 . The deuteronbeam loses a part of its energy in the target and the deuteron energy takes about 20 MeV at thecenter of the target. Typical value of the beam intensity at the target was about 400 nA. The
emitted protons from 208 Pb(d.p) reactions were momentum-analyzed by QDQ magnetic analyzer
system[2] and focused on the polarimeter target. The horizontal and vertical angular spreadsof emitted protons were ±2◦ and ±1◦ , respectively. A spectrum of emitted protons is shown in
Figure 1. The spectrum was obtained by changing the magnetic ﬁeld of the Dipole magnet of the
QDQ-magnet analyzing system. The peak corresponding to the transition to the ground state of
209 Pb was separated from the transition to the ﬁrst exciting state.
Figure 2 shows a comparison of the present experimental data with a ﬁnite-range DWBA andcontinuum discretized coupled channel (CDCC(d,p)) calculations. These calculations predicted
negative values at forward angles, however, the experimental values were zero within the statisticaluncertainties. At present we could not predict the measured proton polarization.

0.4
Proton polarization

25000
5/2+ , 15/2+
20000
15000

9/2+ ground state

10000

0.2
0
-0.2
-0.4

5000
11/2+
0
19.5

0

20

40

60

80

100 120 140 160 180

C.M. angle [degree]
20

20.5

21

21.5

22

22.5

Proton energy [MeV]Fig. 2. Polarizations of the emitted protons
from the 208 Pb(d,p)209 Pb reaction+
to 92 ground-state. Solid line represents the result of DWBA calculations. Dashed line shows the
CDCC(d,p) calculation.

Fig. 1. Energy spectrum of the protons
coming from the 208 Pb(d,p) reactions.

References[1] M. Yamaguchi, T.Katabuchi, N,Yamada, N.Kawachi, Y.Tsuchiya, K.Sawada, T.Takizawa,
K.Takagi, K.Masuno and Y.Tagishi, UTTAC Annual Report 66, 7(1997)[2] Y. Aoki, S. Hiroki, M. Tomizawa, Y. Tagishi and K. Yagi, UTTAC Annual Report 52, 5(1987)- 31 -

2.5

The 6Li(d,αα)4He reaction at an incident energy of 90 keV

T. Iizuka, M. Yamaguchi, N. Kawachi, N. Yoshimaru, K. Shiga and Y. Tagishi
The reaction 6Li(d,α)4He at energies below the Coulomb barrier has been studied to understandnucleosynthesis in the early universe [1]. The experimental data of the cross sections suggested that the6

Li(d,α)4He reaction might be dominated at low energies by a broad 2+ subthreshold resonance in thecompound nucleus 8Be [2]. In the present works, we have measured the analyzing powers iT11, T20, T21
and T22 fro the 6Li(d,α)4He reaction at an incident energy of 90 keV for more understanding of the reaction
mechanism for this reaction at energies below the Coulomb barrier.
The emitted alpha particles were detected simultaneously by eleven silicon photodiodes(HAMAMATSU S2744) placed in a scattering chamber at every 20¡from +90¡to +90¡-90¡and 0¡in thelaboratory system. Each anode of photodiodes placed at θ=+90¡to +10¡and –90¡to –10¡was connected inseries with resistances and each cathode was also connected in series without resistance. As shown in Fig.
1, we could clearly distinguish signals from each counter by applying a position detecting method withcharge division. The solid angle of each counter was 20 msr, which corresponded to a detector angular
acceptance of ∆θ=3 ¡ . Experiments were performed with 90 keV polarized deuteron beam from a
Lamb-shift type polarized ion source at UTTAC. The 6Li target was prepared by vacuum evaporation of
6

Li2CO3 onto a 15 µm thick aluminum foil, whose thickness was about 10 µm/cm2. The energy loss of theincident deuterons in the 6Li2CO3 target was estimated about 8 keV.
Angular distributions of the four analyzing powers are shown in Fig. 2. All the measured vector
analyzing powers are zero within the statistical errors. However, three tensor analyzing powers (T20, T21
and T22) present large angular distributions. The differential cross sections have almost constant values ofabout 20 µb/sr for all scattering angles. We compared present data with the calculations of the compoundreaction model [3]. In this model, we considered formation of a single resonance state of 2+ of 8Be withs-wave incident deuterons. Results of calculations are shown in Fig. 2 as solid lines. All the measured
tensor analyzing powers are well reproduced by these calculations.

References[1] R. A. Malaney et al., Phys. Rep. 229, 145 (1993)[2] K. Czerski et al., Phys. Rev. C55, 1517 (1997)[3] F. Seiler, Nucl. Phys. A286, 1 (1977)- 32 -

70
80
Counts

500

50

60

400

40

300

20

30

200

0
Fig.1.

0

10

100

0

100

200

300

400

500

Two dimensional spectrum between energy and position. In the energy spectrum, alpha particles
for each counter are correspond to around 300 channel.

0.3

0.4
Resonance(2+)

Resonannce(2+)

0.2

0.2

0.1

0

iT11 0

T20-0.2

-0.1

-0.4

-0.2

-0.6

-0.3

-0.8
0

10

20

30

40

50

60

70

80

90

100

0

10

20

Angle(c.m.)

40

50

60

70

80

90

100

0.1
Resonannce(2+)

0.4Resonannce(2+)
0

0.35
0.3

T21

30

Angle(c.m.)

0.45

-0.1

T22

0.25
0.2

-0.2

0.15
-0.3

0.1
0.05

-0.4

0
-0.05

-0.5
0

10

20

30

40

50

60

70

80

90

100

0

10

20

Angle(c.m.)Fig.2.

30

40

50

60

70

80

90

100

Angle(c.m.)Comparison of analyzing power of the 6Li(d,α)4He reaction at an incident energy of 90 keV. The
solid curves are results of the compound reaction model.

- 33 -

2.6

Spin precession measurement of polarized proton ions bytransient magnetic ﬁeld

T. Komatsubara, K. Sasa, T. Katabuchi, M. Yamaguchi, T. Iizuka, H. Oshima, Y.J. Ma, Y.
Sasaki, S. Yokose, M. Ishizuka, Y. Tagishi, K. Furuno, T. Koyano 1

Transient magnetic ﬁeld (TMF) is known as hyperﬁne interaction between a magnetized foil
and a fast traveling nucleus[1]. Since the ﬁrst observation of the TMF by Borchers[2], nuclear
magnetic moments for many nuclei in a wide range of mass region were measured by using the
TMF of several thousand tesla.
The magnitude of TMF can be calculated from Fermi contact ﬁeld B0 multiplied by the
charge fraction q(1s) of a hydrogen like atom and the spin polarization p(1s) of 1s electron, as thefollowing formula.
B = B0 · p(1s) · q(1s) .
The Fermi contact ﬁeld B0 can be calculated as B0 = 16.7Z 3 [tesla] without relativistic correction.
The strength of TMF depends on the ion velocity. When the ion velocity is the same order ofcmagnitude as the 1s electron velocity v = Zv0 , where v0 denotes Bohr velocity v0 = 137, TMF
interaction is supposed to be most eﬀective. In the lower velocity region, velocity dependence of
TMF is well studied. However, a few measurements were reported for the higher velocity region.
Brennan[3] reported very small amplitude of TMF for µ+ ions whose velocity is 0.69c.
In order to detect TMF for the higher velocity region spin precession measurements were
performed by using a polarized proton beam at the 12UD tandem accelerator center of Universityof Tsukuba. A magnetized iron foil of 50 µm in thickness was irradiated by 7MeV polarized
protons. Because of stopping power in the iron foil for the traveling protons, the energy ofejected proton ions is degraded to be 5 MeV. For the measurements of the spin precession, twopolarimeters were installed at upstream and downstream of the iron foil. Two 2mg/cm2 carbon
foils were used as scattering targets of the polarimeters located at 80 mm upstream and 60
mm downstream of the iron foil. Asymmetries of elastically scattered protons were measured
by using left and right Si detectors at angles of +50◦ and −50◦ , respectively. The analyzing
powers depending on the the proton energy were measured to be −0.27 and −0.87 for the 7.0
and 5.0 MeV, respectively. Initial direction of the polarized proton was chosen to be parallel tothe beam axis. When magnetic ﬁeld is added in the foil along to horizontal plane, asymmetry of
the scattered protons appears proportional to the spin precession.
Two kinds of experiments were done by using the magnetized iron foils. In the ﬁrst experiment,
an electro-magnet shown in Fig. 1 was used to change the polarity of the external magnetic ﬁeld
by the electric current. The number of turns of the coil 150. When the coil was excited by acurrent of 1.0 A, magnetic ﬁeld in the thin iron foil was saturated. The saturation was detectedby the rf electro-magnetic induction coils described in our previous report[6]. However, fringing
magnetic ﬁeld also appeared around the gap space. In order to reduce the fringing ﬁeld, irontubes were installed to cover beam axis shown in Fig. 1. The tubes work as magnetic ﬁeld cramps
to cut the fringing ﬁeld to be 35 gauss on the iron foil.
In another experiment, thin iron foils were prepared as permanent magnetic strips shownin Fig. 2. The strips were magnetized by strong magnetic ﬁeld. The magnetic ﬁeld density B
inside of the magnetized foils were deduced from integral of induction voltage measured by digital
oscilloscope (DSO) as shown in Fig. 2. When we dropped the strip through a pick up coil of 80
1

Cryogenics Center- 34 -

turns induction voltage was appeared as shown in an envelope of Fig. 3(a). The time integral ofthe voltage shown in Fig. 3(b) corresponds to 1.2 tesla.
In Fig. 4, shift angles with the magnetized iron foils are indicated as “Fe−B” and “Fe+B”
for the opposite directions of the magnetization. In order to evaluate fringing ﬁeld, reference
measurements were done by using a copper foil of the same thickness as the iron foil. Results forthe copper foil are shown as “Cu−B” and “Cu+B”. For the zero ﬁeld measurement, a copper foil
was used without external magnetic ﬁeld. However, the result for the zero ﬁeld shown as “Cu” inthe Fig. 4 is not consistent to the other data with magnetic ﬁeld. Unexpected stray ﬁeld could
aﬀect the result. When an internal magnetic ﬁeld of 1.2 tesla is subtracted, the measured valueof the TMF can be deduced as 1.2 ± 3.2 tesla.
Fig. 5 shows the results for the permanently magnetized strips. Data points indicated as“Fe−B” and “Fe+B” show shift angles by the magnetized iron foils. Reference measurementswith copper and iron foils are shown as “Cu” and “Fe”. The “Cu” data agrees as zero magnetic
ﬁeld. However, the result “Fe” is not the center between “Fe−B” and “Fe+B”. This result could
be explain by unexpected small magnetization of the foil. When an internal magnetic ﬁeld of 1.2
tesla is subtracted, the measured value of the TMF can be 0.9 ± 2.4 tesla.
Consequently, signiﬁcant strength of TMF was not observed by both experiments. Bothresults can not be account for spin precession by TMF beyond error bars. Reason of the absence
could be explained by high velocity of protons. When the ions travel through the iron foil where
the average velocity is 15.4 v0 in the unit of Bohr velocity, electric charge state of the proton is+1. This means that no electron exists to create TMF at position of nucleus. If we extend moresigniﬁcant region to detect the TMF, more heavier ion could be candidate as shown in Fig. 6
where ion energies corresponding to v0 ·Z velocity are compared with the maximum energies at
UTTAC.

References[1] N.B. Koller, M. Hass, J. Sak, Ann. Rev. Nucl. Part. Sci. 30 (1980) 53[2] R.R. Borchers, J.D. Bronson, D.E. Murnick, L. Grodzins, Phys. Rev. Lett. 17 (1966) 1099
[3] J.M. Brennan, N Benczer-Koller, M. Hass, W.J. Kossler, J. Lindemuth, A.T. Fiory, D.E.
Murnick, R.P. Minnich, W.F. Lankford, C.E. Stronach, Phys. Rev B18 (1978) 3430
[4] M.P. Robinson, A.E. Stuchbery, E. Bezakova, S.M. Mullins, H.H. Bolotin, Nucl. Phys. A647
(1999) 175[5] S.J. Moss and W. Haeberli, Nucl. Phys. 72 (1965) 417[6] T. Komatsubara, K. Sasa, T. Katabuchi, M. Yamaguchi, K. Kudo, K. Sawada, I. Masuno, T.
Iizuka, H. Oshima, Y.J. Ma, Y. Sasaki, K. Yamada, S. Yokose, M. Ishizuka, M. Yoshimoto,Y. Tagishi, K. Furuno, T. Koyano, UTTAC annual report 2000, UTTAC-69, (2001), 43- 35 -

Field cramp

Iron foil

Field cramp

Fig. 1. A magnetic circuit with electric coils, return yoke and a thin iron foil. In order to reduce
fringing magnetic ﬁeld, ﬁeld cramps made of iron pipes were located entrance and exit for the
foil on the beam axis.

B

B

DSO

Fig. 2. Two strips of permanently magnetized iron foils. A detecting device for themagnetization consisting of a digital oscilloscope (DSO) and a pickup coil is also shown. Whena strip of foil is dropped along to the guide pipe and passes through the pickup coil, inductedvoltage can be recorded by the DSO.

- 36 -

Coil No.1 2001−09−28

10

Voltage [mV]

(a)
5

0

−5

−10
0

10

30

40

50

40

50

Magnetic Flux [micro Wb]

Time [msec]
40

(b)
30

20

10

0
0

10

30

Time [msec]

Fig. 3. (a) Inducted voltage and (b) its time integral recorded by the DSO shown in Fig. 2.

Shift Angle [degree]

0.8
Shift angles by iron and copper foils
with magnetic circuit and field cramp
0.6

0.4

Fe−B Cu−B

Cu+B Fe+B

0.2

Fig. 4. Results of spin precession for the electric-magnetic experiments.

- 37 -

Shift Angle [degree]

0.6

0.5

0.4

Cu

Fe−B

0.3

Fe+B

0.2

Iron Energy [MeV]Fig. 5. Spin precessions measured for the stripped foils of permanently magnetized iron foils.

10 GeV

19 F
1 GeV

77MeV

100 MeV
10 MeV

Energy available
at UTTAC

35 Cl
1 MeV

110MeV

100 keV
0

20

40

60

80

Fig. 6 A solid line shows ion energies corresponding to Bohr velocity. Closed circles indicate themaximum energy available at UTTAC.

- 38 -

2.7

High-spin states in 127I

Y. H. Zhang1, Y. J. Ma, Y. Sasaki, K. Yamada, H. Ohshima, S. Yokose, M. Ishizuka,
T. Komatsubara, and K. Furuno

Excited states of transitional nuclei 117-127I have been investigated previously in Refs.
[1-4]. The collective features systematically observed in these nuclei are the occurrence of∆I=2 bands with stretched E2 transitions based on 5/2+, 7/2+, and 11/2− states, and a ∆I=1
band characterized by M1 cascade and E2 crossover transitions based on a 9/2+ state. The∆I=1 band was explained as a rotational band based on a deformed g9/2 proton hole state. The∆I=2 bands, on the other hand, have been described as decoupled bands based on the bandheads arising from d5/2, g7/2, and h11/2 proton configurations [1-4], respectively. However, theinter-band M1+ E2 transitions between the members of proposed d5/2 and g7/2 bands have beenfound in the recent investigations on 121,123I [5-7] and 125I [7,8]. These authors attributed suchcoupled structures to the πg7/2 configuration with admixture of d5/2 quasiproton. An oblate
shape associated with this band was also proposed [5,6] according to the calculations within
the Strutinsky formulism using a Woods-Saxon potential. Calculations within the
core-quasiparticle coupling model [9,10] predict the existence of two coupled bands in 123,125I
based πg7/2 and πd5/2 configurations at low excitation energies. A search for the πd5/2 coupledband in 125I has been made but no positive evidence has been observed [8]. A previous
investigation on 127I [3,4] shows the ∆I=2 sequences of levels based on 5/ 21+ (g.s) , 7 / 21+ , and++−11/ 21− states up to 21/2 , 19/2 , and 23/2 respectively. In order to identify new levels andtransitions, and for understanding the nature of various bands, the structure of 127I has been
reinvestigated by in-beam γ-ray spectroscopic measurements in this work.
The experiment was performed at the Tandem Accelerator Center of University ofTsukuba. We used the 124Sn(7Li,4n)127I reaction to populate the yrast and near-yrast levels in
127

I. The 7Li beam was provided by the tandem accelerator in the University of Tsukuba. The

target was an enriched self-supporting 124Sn metallic foil of 4 mg/cm2 thickness. A γ-ray
detector array composed of one planar detector and 9 BGO-Compton-suppressed Ge detectors
was used for the in-beam γ-ray measurements. Five Ge detectors were positioned at 370 andthe others near 900 with respect to the beam direction so that the DCO ratios (Directional
Correlations of γ-ray de-exciting the Oriented states) could be deduced from the coincidence
data. All the detectors were calibrated using standard 152Eu and 133Ba sources; typical energy
resolution was 2.0∼2.5 keV for the 1332 keV line from 60Co source. The beam energy of 32
MeV was used during x-γ and γ-γ-t coincidence measurements. A total of 40 millions γ-γ-t and3 millions x-γ coincidence events was accumulated. These coincidence events were sorted

1

Institute of Modern Physics, the Chinese Academy of Sciences, Lanzhou 73000, P. R. China- 39 -

into a symmetric and a non-symmetric (DCO sorting) matrix for off-line analysis.
From detailed analysis on the γ-γ coincidence relationships, γ-ray relative intensities, and
DCO ratios, a new level scheme of 127I has been established as shown in Fig. 1, which islargely extended comparing to the previous one [3]. In this work, some high-energy andclose-lying double peaks have been identified, and the observed crossover transitions and γ-γ
coincidence relationships support the placements of new γ-transitions in the present level
scheme.
The negative-parity states labeled as (A) in Fig. 1 are extended from the 23/2− level
previously observed [3] up to (35/2−) state at 5243 keV excitation energy. The 374 keV line
feeding to the 23/2− level [3] has not been observed in this work. The deduced DCO ratios
show stretched quadrupole characters for 982-, 1013-, and 601-keV γ-rays and dipole
characters for 410- and 274-keV lines. These results support the spin and parity assignments
for the levels above 23/2− state. A sequence of levels based on 11/2− state has been observedin 119∼127I and explained as decoupled bands based on the h11/2 proton configurations [1-4]. The
decoupled nature of these bands is inferred from the similar energy level spacings with thoseof the corresponding even-even cores. This is really the case comparing the negative-parity
states in 127I with the ground-state band in 126Te [11] which is presented in Fig. 1 by black dots.
The similar level spacings suggest that the negative-parity levels from 11/2− through (27/2− )are formed by coupling the aligned h11/2 proton to the core states from 0+ through 8+.
The two ∆I=2 sequences of band (C) have been established previously [3] up to 19/2+ and21/2+, respectively, by adding 880- and 934-keV transitions to the yrast 15/2+ and 17/2+ states.
These two γ rays may be the 877- and 930-keV lines observed in this work. Several parallel
crossover transitions de-exciting a new level at 2901 keV support the placements of theassociated γ transitions and γ-ray energies determined in this work. Three new γ rays (912,812, and 851 keV ) are observed and placed in the level scheme extending the ∆I=2 sequences
up to (25/2+) and (23/2+) respectively. The deduced DCO ratios show stretched quadrupole
characters for 912-, 812-, 850- 545-, 930-, and 1171-keV γ rays, and dipole characters for
113-, 95-, 156-, and 294-keV lines supporting the spin and parity assignments shown in the
figure. Above (23/2+) state at 2901 keV, a ∆I=1 cascade with weak crossover transitions has
also been observed. This band is probably a 3-qp band.
The two ∆I=2 cascades of band (C) have been described in Refs. [1,4] as decoupledbands based on the bandheads arising from d5/2 and g7/2 proton configurations, respectively.
The strong inter-band band transitions (593- and 550-keV γ rays) between these ∆I=2
sequences suggest that these ∆I=2 bands have similar configuration with a large overlap intheir wave functions. Other inter-band transitions (214-, 396-, 481-, and 432-keV γ rays) arealso observed connecting states up to 21/2+ at 2788 keV. Based on this and systematics ofsimilar bands and decay patterns in the neighboring iodine nuclei [5-8], the two yrast ∆I=2
bands may be interpreted as signature partners of same configuration. The α=−1/2 signature- 40 -

branch is favored in energy, therefore, the main component may be the g7/2 proton
configuration. The 651-keV transition is assigned as out-of-band decay as arranged in Fig. 1.
Apart from the yrast positive-parity band discussed above, two new ∆I=2 cascades
labeled as band (B) have been newly observed feeding to the second 7/2+ and 9/2+ states. The
linking transitions with h11/2 decoupled band and g7/2 band fix the ordering and the spin-parity
of associated levels. On the other hand, weak inter-band transitions (116-, 562-, and 475-keVlines) are also observed. These two ∆I=2 cascades are very probably based on the d5/2 proton
configuration. The observation of both πd5/2 and πg7/2 bands is consistent with theoreticalpredictions within the core-quasiparticle coupling model [9,10].

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

D. M. Gordon, M. Gai, A. K. Gaigalas et al., Phys. Lett. B67, 161 (1977)
U. Hagemann, H. J. Keller, and H. F. Brinckmann, Nucl. Phys. A289, 292 (1977)
R. E. Shroy, D. M. Gordon, M. Gai et al., Phys. Rev. C26, 1089 (1982)
M. Gai, D. M. Gordon, R. E. Shroy et al., Phys. Rev., C26, 1101 (1982)
Y. Liang, D. B. Fossan,, J. R. Hughes et al., Phys. Rev. C45, 1041 (1992)
Y. Liang, D. B. Fossan, J. R. Hughes et al, Proceedinds of the International Conference on
High Spin Physics and Gamma-soft Nuclei, Saladin J X et al ed. (World Scientific Press,
Sigapore ) 1991. 308-314
7) R. Goswami, B. Sethi, P. Banerjee, Phys. Rev. C47, 1013 (1993)
8) H. Sharma, B. Sethi, R. Goswami et al., Phys. Rev. C59, 2446 (1999)
9) F. Donau, U. Hagemann, Z. Phys. A293, 31 (1979)
10) L. G. Kostova, W. Andrejtscheff, L. K. Kostov et al., Nucl. Phys. A485, 31 (1988)
11) C. T. Zhang, P. Bhattacharyya, P. J. Daly et al., Nucl. Phys. A628, 386 (1998)- 41 -

- 42 -

2.8

Determination of excitation energies and level structure
in high-spin states of 116I

C.-B. Moon*, T. Komatsubara, T. Shizuma, Y. Sasaki, K. Uchiyama, K. Matsuura, M. Murasaki,
H. Takahashi and K. Furuno* Department of Physics, Hoseo University, Chung-Nam 336-795, Korea
E-mail: cbmoon@office.hoseo.ac.kr

1. Introduction
A few years ago, a preliminary result about the in-beam spectroscopy of 116I was given in this annual
report [1] still leaving excitation energies to be unknown. Here, we report that the excitation energies ofstates in 116I have been determined. Before the present work, the excitation energies for the observed
deformed bands have been unknown, although several investigations for the level structure of 116I byusing in-beam spectroscopy were done [2-4]. Consequently, the bands observed in this nucleus could not
be connected and thus remained to be isolated from each other,
The level structure was studied with the 103Rh(16O, 3n)116I reaction at a beam of 80 MeV. The beam
was provided by the 12UD tandem accelerator at the University of Tsukuba. The 103Rh target was a foilof 1.0 mg/cm2 in thickness on the Pb backing of 3 mg/cm2 in thickness. The γ-ray spectra were takenwith 7 high-purity (HP) Ge detectors with BGO anti-Compton shields (ACS). One of them was the low
energy photon (LEP) detector to ensure sensitivity for important low-energy transitions at the bottom
parts of γ-ray cascades. For the DCO ratios, the coincidence events were sorted into an asymmetricmatrix with energies of γ rays detected in 5 detectors at 1170 along one axis and energies of γ rays
detected in a detector at 00 along the other axis. The intensities of Iγ(1170) and Iγ(00) used to determine
the DCO ratio, R = Iγ(1170)/Iγ(00), for the transitions of interest were extracted from spectra obtained by
setting gates on the 1170 and 00 axes of the γ–γ asymmetric matrix. Measured angular correlation ratios,
R = Iγ(370)/Iγ(790), are included in Table 1 together with excitation energies, relative intensities and spinparity assignments of the transitions in 116I.
2. Level scheme of 116I
a. Low-spin states labeled 1
Fig.1 shows the level scheme of 116I deduced from the present work. The ordering of the γ-ray
transitions has been derived from coincidence relationships and relative intensities. Information on γ-ray
multipolarities was obtained from DCO ratios as mentioned earlier.
The low-lying states labeled 1 between the ground 1+ state and the (10+) state at 1097.3 keV were
definitely established in the present work. Thereby, excitation energies for the observed deformed
rotational bands have been determined. It should be emphasized that there is no ambiguity in thetransition order in these low-lying states because all the transitions are, as shown in Fig.1, intertwinedwith each other through the crossing-over transitions. The DCO ratios indicate that the 227-keVtransition shows ∆I = 2 type of quadrupole in nature while the 114-keV transition of dipole character.
Unlike other neighboring odd-odd isotopes with the ground state of 2-, the spin-parity of the ground stateof 116I has been known to be 1+. We propose that the state at 227 keV should be 3+. By the intensity
balance arguments for the 114-keV transition, the multipolarity is suggested to be E1 rather than M1 asshown in Table 2 and thus the spin-parity of the state at 341.1 keV is likely 4-. The 149.5-keV transition
feeding the 227-keV state by crossing over the 341.1-keV state was found to be of quadrupole character.
So the spin-parity of the 376.5-keV state might be 5+. This state was fed mainly by the 92-keV transition
and weakly by the 195- and 142.5-keV transitions. The multipolarity for the 92-keV transition was
indicative of dipole character in the DCO ratios. In the mean time, the spin-parity of the 468.5-keV stateon which band 3 is built was assigned to be 8-. As shown in Fig. 1, the 92-keV transition is depopulated- 43 -

from this state and thus its multipolarity should be E3. From the point of view about the intensity balance
argument, however, E2 or M2 cannot be excluded.

7

116
53 63

I

4

1017.9907.861014.5

958.8
-

(10 )

607.5 .4
3
(9 )
28
2
-

(7 )
T1/2=3.27 µs

21 504.4 .0
(8 )

717.8
(12 )
697.6
(10 )
663.7

44.3

-

(8 )

140.3 430.4

65.8
106.1
109.9
104.3

37
8.
7

672.8

3

2

+

756.3

560.0

+

468.4 248.2

91.5 +_(4 )223.0 874.3(5 ) 376.5 92.0

149.5
+

+

(9 ) +
189.4 (8 )

33.6

302.7

571.6
103.1 195.1

T1/2 = 2.91 s (3 )

1

528.7
+
(11 )

20
.2

(10 )

341.1

2532.7621.2 08
3
+
(12 )
2

869.5

1097.3

468.5

760.7
+
(15 )

658.5
+
(13 )
.5

.8

79
0.9

38
7.
0
744.5 .5
7
(12 )
35
(11 )
32 681.6
4.
1
-

749.1
8
5.
+
34
(14 )

9

2547.6537
595 .3.2

93.
803.0 40

4
7.

776.2

-

(14 )

405

-

557.8

0

35

+

(14 )

(17 )

(17 )

882.8
(16 )

748.3

+

3527.0
+

(16 )

902.1

916.7
904.1

854.4

612.6

6.

(19 )

994
.3

808.4

-

+

(19 )
+

987.6
+

(16 )

995.7

4806.4

(18 )

46
2.
9
41

8

985.8

2
9.
43

-

+

(20 )

989.1
-

2

855.2
(13 )

(21 )

647.8

8.
48

(15 )

+

(21 )

+

(18 )

951.1
-

5
-

49
7.
6

-

1075.7

875.7

(18 )
(17 )

926.4

(20 )

4980.0
-

-

(22 )

-

(22 )

907.7

10

6262.3

50.5
142.5
35.4

227.0

1063.7

355.3

209.8

288

5887.7

+

(23 )

+

(24 )
276.2

327.3

804.3

(23 )

-

6215.0(25)7170.1

184.7
138.7

519

39.2

177.9 341.1

1

114.1

Fig.1 Level scheme of 116I deduced from the reaction 103Rh(16O,3n)116I at a beam energy of 80 MeV. Transitionand excitation energies are given in keV.

Two strongly populated transitions, which are the 355.3- and 302.7-keV ones, from the 8+ state at 874.3
keV are noticeable. Surprisingly, depopulating γ-rays from the states fed by these two transitions are
fragmented into a lot of weak-intensity transitions among which the 50.5- and 39.2-keV ones are very
low in energy. The DCO ratios indicate that these 355.3- and 302.7-keV transitions are of dipole
character and thus the spin of the 519.0- and 571.6-keV states is likely 7. This means that the
depopulating transitions would have quite high multipolarities, such as λ = 2 or 3. It is well known that γ-- 44 -

(a) 104 keV gate
106
66

150

(b) 106 keV gate
66

100

250

104

50

44

Counts/Channel

0
150

104

50

44

100

110

200

110

rays decaying from an isomer might be of high multipolarity transitions. The present result, therefore,
opens a question that there would be some isomers in these low-lying states.

(c) 110 keV gate

106

200

66

150

50

44

100

0
100

150

200

Channel Number
Fig.2. γ-ray spectra detected by a LEP in coincidence with the 104-, 106- and 110-keV transitions.
Energies are given in keV.

b. Low-lying states labeled 2
Before the present work, the excitation energy of the 7- isomer with half-life of 3.27 µs was not known.
The spin-parity assignment for this state was made following the systematics of the πg9/2νh11/2 deformed
bands observed in the neighboring heavier isotopes [4]. This isomer was identified and its life-time wasmeasured by Wu et al [5]. Two independent branches associated with the decay of this isomer wereobserved [5]: one includes 65.4-,105-(a doublet), and 109.6-keV transitions and the other 114.2-and
227.2-keV transitions. In the present work, the excitation energy of this isomer was found to be 430.4
keV. This result came from the coincident relationship between band 3 built on the 8- state at 468.5 keVand excited states built on this isomer (see Fig. 1). If this result is correct, a missing transition should beobserved together with the 65.4-,105-(a doublet), and 109.6-keV transitions. In other words, the 44.3keV transition that corresponds to the energy difference between the 430.4 keV and the sum energy,386.1 keV, of the 65.8-, 104.3-, 106.1- and 109.9-keV transitions should exist below this isomer. It isnoted that a doublet 105 keV transition could be separated into the 104.3- and 106.1-keV transitions. In
the present work, such a 44.3-keV transition could be identified. As shown in Fig. 2, the 44-keV peak is- 45 -

clearly seen in spectra gated by the 104-, 106- and 110-keV transitions. Some useful informations for thetransitions below this isomer are presented in Table 2 where relative intensities, experimental internalcoefficients and theoretical internal coefficients are included. The present experimental internalcoefficients were derived from the intensity balance arguments assuming the 110-keV transition thatshould be E2 since it was shown to be of dipole character in DCO ratios.
Closely looking at the summed delayed γ-ray spectrum in [5], we find two small peaks that were notnoticed by the authors, which are the 89- and 150-keV peaks. Interestingly, the 89-keV peak isequivalent to the transition energy between the isomer at 430.4 keV and the 341.1-keV state. If this 89keV peak is a real transition from this isomer, it is possible to explain the reason why the 227-and 114keV transitions were observed in the delayed γ-ray spectrum in [5]. Furthermore, the 150-keV peak may
correspond to the 149.5-keV transition from the 376.5-keV state to the 227-keV state.
c. Bands 3 and 4
Band 3, which comprises the 663.7-, 697.6-, and 717.8-keV transitions, was newly identified in thepresent work. As was already mentioned, the observation of this band made it possible to extract theexcitation energy of the isomer to be 430.4 keV. The 14- state at 2547.6 keV, on which more strongly
populated transitions are built, might be based on the four-quasiparticle configuration. The spin-parity
assignment for this state was suggested to be 13- in a previous work [2]. We propose that, however, its
spin-parity should be 14-. The present spin-parity assignments are essentially based on the multipolarityof the interband transitions connecting band 10, namely the 403.9- and 790.9-keV transitions. The DCO
ratios indicate that the 403.9 keV is ∆I=1 transition with mixed M1/E2 while the 790.9-keV one is ofquadrupole character indicating ∆I=2 transition with E2. Furthermore, by taking into account of the γ-ray
intensity at a given angular momentum in band 4 and band 10, the present assignment is more reliable
than that of former result [2].
Band 4 was already identified in [2].
d. Bands 5 and 6
These bands built on the 8+ state at 874.3 keV, to which we assign positive parity, are well developed
into rotational structure above the 10+ and 11+ states. The positive-parity assignment could be made byassuming that they should be based on the πh11/2νh11/2 configuration. The present assignment can bejustified by arguing the fact that negative-parity states based on the proton h11/2 orbital was most strongly
populated in the neighboring odd-A I, such as 115I [6] and 117I [7]. Interestingly, one can see a similar
pattern in the positive-parity bands in odd-odd 120Cs [8] and 122Cs [9] where signature inversion feature
was revealed at lower spin states. More higher-spin states in these bands were established by Paul et al.
[3] using the Eurogam spectrometer and the positive-parity assignment was made to these bands with a
πh11/2 νh11/2 structure on the basis of blocking arguments of a neutron h11/2 pair and a proton h11.2 pairalignments.
e. Band 7
This band is somewhat pecular. First, the transition intensity is all most the same by showing no side
feeding transitions between the 3527- and 7170-keV states. Second, the transition energy is quite
irregular that shows no rotational structure. Finally, this band is strongly correlated with the 23+ state inband 6 through the 907.8-keV side-feeding transition.
The underlying physics involved in this band has not yet known. A possible explanation, however, may
be put so that it might originate from correlations between the πh11/2νh11/2 configuration and thevibrational motion seen in the neighboring even-even Te core. Such a quasi γ-band built by the couplingof the proton h11/2 orbital and the vibrational band were observed in odd-even 117I [7]and 119I [10].
f. Bands 8 and 9- 46 -

Band 8 was newly identified but could not be established its excitation energy. The population intensity
for band 8 was estimated to be about 8 % relative to that of the 227-keV transition. Band 9 was also
newly observed in the present work. These two bands may be associated with the πg7/2νh11/2
configuration.
g. Band 10
This band has been well known as being based on the proton hole g9/2 orbital coupled to the neutron
h11/2 orbital in previous works. In the present work, some more higher-lying transitions were identified.
References[1] C.-B. Moon et al., Tandem Accelerator Center Annual Report, UTTAC-65 (1998).
[2] E.S. Paul, R.M. Clark, S.A. Forbes, D.B. Fossan, J.R. Hughes, D.R. LaFosse, P.J. Nolan,
P.H. Regan, P. Vaska, R. Wadsworth and M.P. Waring, J. Phys. G: Nucl. Part. Phys. 19 (1993) 343.
[3] E.S. Paul, D.B. Fossan, K. Hauschild, I.M. Hibbert, H. Schnare, J.M. Sears, I. Thorslund,
R. Wadsworth, A.N. Wilson, and J.N. Wilson, J. Phys. G: Nucl. Part. Phys. 21 (1995) 995.
[4] M.A. Quader, W.F. Piel, S. Vajda, W.A. Watson III, F.C. Yang, and D.B. Fossan, Phys. Rev. C 30
(1984) 1772.
[5] C.Y. Wu, M. Satteson, K. Wang, D. Cline, H.E. Gove, S.S. Hanna, M. Hass, R. Ibbotson and
A.V. Ramayya, Phys. Rev. C 41 (1990) 1600.
[6] C.-B. Moon, T. Komatsubara and K. Furuno, Tandem Accelerator Center Annual Report,
UTTAC-68 (2000), p.49.
[7] C.-B. Moon, T. Komatsubara, T. Shizuma, Y. Sasaki, H. Ishiyama, T. Jumatsu and K. Furuno,
Eur. Phys. J. A 5 (1999) 13.
[8] C.-B. Moon, S.J. Chae, J.H. Ha, T. Komatsubara, Y. Sasaki, T. Jumatsu, K. Yamada, K. Satouand K. Furuno, Nucl. Phys. A 696 (2001) 45.
[9] C.-B. Moon, T. Komatsubara and K. Furuno, Nucl. Phys. A 674 (2000) 343.
[10] S. Törmänen, S. Juutinen, R. Julin, A. Virtanen, G.B. Hagemann, Ch. Droste, W. Karczyk,
T. Morek. and J. Srebrny, Nucl. Phys. A 613 (1997) 282.

- 47 -

Table 1. Level energies, γ–ray energies, DCO ratios, and spin-parity assignments to 116I following
the 103Rh(16O,3n)116I reaction at a beam energy of 80 MeV.
Rb

Iγ a

Multipolarity

Assignment

M1/E2(10+) → (9+)

Ei (keV)

Ef (keV)Eγ (keV)1097.31063.7

33.6

376.5

341.1

35.4

519.0

479.8

39.2

519.0

468.5

50.5

560.0

468.5

91.5*

468.5

376.5

92.0*

571.6

468.

103.

341.1

227.0

114.1

925

479.8

341.1

138.7

97

570.7

430.4

140.3

250

0.6

M1/E2

(8-) → (7-)

519.0

468.5

142.5

26

0.6

dipole(7) → (5+)

376.5

227.0

149.5

89

0.8

E2

(5+) → (3+)

519.0

341.1

177.9

38

0.9

664.5

479.8

184.7

75

0.6

dipole1063.7

874.3

189.4

455

0.4

M1/E2

571.6

468.5

195.1

89

0.7

874.3

664.5

209.8

38

0.4

1505.71345.5

220.2

81

791.7

570.7

221.0

285

1097.3

874.3

223.0

227.0

0

1345.5(5+) → (4-)(7) → (5+)
0.6

285

0.4

dipole(8-) → (5+)

dipole(7) → (8-)E1(4-) → (3+)

dipole(7) → (4-)(9+) → (8+)(7) → (5+)
dipoleM1/E2(12+) → (11+)

1.0c

M1/E2

(9-) → (8-)

277

0.9

E2

(10+) → (8+)

227.0

1000

1.0

E2

3+ → 1+1097.3

248.2

210

M1/E2

(11+) → (10+)

6215.05938.8

276.2

34

E2

(24-) → (22-)

3872.93026.2

283.4

220

1.0c

M1/E2

(10-) → (9-)

874.3

571.6

302.7

193

0.5

dipole(8+) → (7)1874.21505.7

308.5

225

0.4

M1/E2

(13+) → (12+)

1399.21075.1

324.1

181

1.0e

M1/E2

(11-) → (10-)

6215.05887.7

327.3

120

1.5c

E2

(24-) → (22-)

2532.72186.9

345.8

142

0.5

M1/E2

(15+) → (14+)- 48 -

Table 1. Continued
Ei (keV)

Ef (keV)Eγ (keV)a

Iγ a

Rb

Multipolarity

Assignment

874.3

519.0

355.3

382

0.5

dipole(8+) → (7)3293.42936.0

357.4

74

0.5

M1/E2

(17+) → (16+)

1756.71399.2

357.5

164

1.1c

M1/E2

(12-) → (11-)

4197.53818.8

378.7

33

M1/E2

(19+) → (18+)

2143.71756.7

387.0

98

1.1c

M1/E2

(13-) → (12-)

2547.62143.7

403.9

51

1.1c

M1/E2

(14-) → (13-)

874.3

468.5

405.8

26

1.1

2559.72143.7

416.0

56

1.2c

M1/E2

(14-) → (13-)

2998.92559.7

439.2

21

1.1c

M1/E2

(15-) → (14-)

3461.82998.9

462.9

21

1.1c

M1/E2

(16-) → (15-)

1565.71097.3

468.4

614

1.1

E2

(12+) → (10+)

3950.03461.8

488.2

17

M1/E2

(17-) → (16-)

4447.63950.0

497.6

12

M1/E2

(18-) → (17-)

1075.1

570.7

504.4

35

1.7c

E2

(10-) → (8-)

1874.21345.5

528.7

104

1.0

E2

(13+) → (11+)

537.3

560.0

537.3

45

0.6

(E1)

(10+) → (9-)

1063.7

468.5

595.2

85

0.5

(E1)

(9+) → (8-)

1399.2

791.7

607.5

55

1.4c

E2

(11-) → (9-)

2186.91565.7

621.1

405

1.0

E2

(14+) → (12+)

2532.7

1874.2

658.5

197

1.1

E2

(15-) → (13-)

1132.2

468.5

663.7

183

1.0

E2

(10-) → (8-)

1756.71075.1

681.6

71

1.8c

E2

(12-) → (10-)

1829.81132.2

697.6

157

1.0

E2

(12-) → (10-)

2547.6

1829.8

717.8

101

1.0

E2

(14-) → (12-)

2143.71399.2

744.5

66

1.7c

E2

(13-) → (11-)

3295.92547.6

748.3

270

1.0

E2

(16-) → (14-)

2936.02186.9

749.1

210

1.1

E2

(16+) → (14+)

3293.42532.7

760.7

160

1.1

E2

(17+) → (15+)

2547.6

1756.7

790.9

59

1.7c

E2

(14-) → (12-)

2559.71756.7803.0

E2(14-) → (12-)

7170.16365.8

804.3

1.1

E2

(25) → (23)4104.33295.9

808.4

1.0

E2

(18-) → (16-)

80- 49 -(8+) → (8-)

Table 1. Continued
Rb

Ei (keV)

Ef (keV)Eγ (keV)Iγ a2998.92143.7855.2

324980.04104.3875.7

2203818.82936.0882.8

983461.82559.7902.1

4197.53293.4904.1

1055887.74980.0907.7

7170.16262.34443.7

Multipolarity

Assignment

E2(15-) → (13-)

1.1

E2

(20-) → (18-)

0.9

E2

(18+) → (16+)E2(16-) → (14-)

1.1

E2

(19+) → (17+)

128

1.0

E2

(22-) → (20-)

907.8

80

0.9

E2

(25+) → (23+)

3527.0

916.7

93

1.0

E2

(19+) → (17+)

6365.85439.4

926.4

66

1.0

E2

(23+) → (21+)

3950.02998.9

951.1

18

E2

(17-) → (15-)

5938.84980.0

958.8

50

E2

(22-) → (20-)

4447.63461.8

985.8

9

E2

(18-) → (16-)

4806.43818.8

987.6

27

E2

(20+) → (18+)

5186.64197.5

989.1

82

1.1

E2

(21+) → (19+)

7229.56215.01014.5678188.07170.11017.982

0.5

dipole6262.35186.61075.740E2(23+) → (21+)

a: Error are estimated to be less than 10% of the quoted values for the transitions with Iγ > 100 and lessthan 25% for the weaker ones. The values are normalized to 1000 for the 227-keV transition.
b: R=Yγ(00)/Yγ(1170)
c: DCO ratios from the gate on 140 keV M1/E2 transition.
* γ ray is a doublet.

Table 2. Intensity, experimental and theoretical internal conversion coefficients for the transitions below
the 7- isomer in 116I.
Theoretical Internal Conversion Coefficients
E2
E3
E4
M1
M2
M3

E (keV)Iγ aExperimental
Conversion Coefficientsb

E1

44.3
65.8
104.3
106.1
109.9

4(1)
11(3)
31(3)
21(3)
28(2)

9.66
1.13
0.386
1.13
0.507

1.63
0.579
0.157
0.151
0.136

10.2
4.31
1.07
1.02
0.914

39.7
24.1
6.10
5.54
4.94

140
129
30.7
29.1
25.7

a: Intensity has been derived from the spectrum gated on Iodine X-ray of 28 keV.
b: Assume that the 110-keV transition should be M1.

- 50 -

6.86
2.24
0.581
0.557
0.507

130
30.7
5.33
5.06
4.50

920
248
37.1
35.0
30.6

2.9

Detection of Rn-flux in the atmosphere

K. Shiga and Y. Tagishi
The most part of the daughter nuclei produced from radioactive decay of radon(222Rn) and thoron(220Rn) are positively charged. Therefore these nuclei can be collected electro-statically by supplying
negative voltage. We applied first to the silicon solid-state detector (SSD) for the direct detection of thesealpha particles [1]. A PIN silicon photodiode from HAMAMATSU (active area of 48×48 mm2, S4276-2) isused by applying a bias of –100 V on the front surface of the detector. We can obtain energy signals of thealpha particles from radioactive decay of the daughter nuclei of radon and thoron.
In order to obtain the absolute values of the radon content in the air, we measured the collecting
efficiency of positively charged 218Po ions (daughter nuclei of radon, T1/2=3 min.) on the surface of thesilicon detector. The silicon detector was mounted in a chamber (350 mm in diameter and 200 mm indepth) filling with 1-atm air of the target room at UTTAC. Counting rate of the alpha particles emitted
from 218Po (energy of 6.0 MeV) was measured by varying the pressure inside the chamber from 1 to 0.1
atm. Results are shown in Fig. 1, where x-axis presents various pressures in the chamber and y-axis
presents yields of alpha particles emitted from 218Po divided by the pressure in the chamber. At lower
pressures the yields divided by the pressure inside the chamber saturate to the constant values. Because at
the lower pressures the mean-free path of the 218Po ion increases, the most of the 218Po ions reach to thesurface of the detector. Then the saturate values are corresponding to the whole numbers of 218Po ions in
the chamber under pressure of 1-atm. We estimated the collection efficiency of 218Po ions to be 28% at
1-atm in the chamber.
Next we checked the linearity of the detected yields of the alpha particles with energy of 6.003MeV to
the quantity of the 218Po ions. First the chamber was filled with 1-atm N2 gas containing 222Rn. We
measured yields of alpha particles with energy of 6.003MeV. We controlled the number of Rn in thechamber as follows: First, we evacuated the chamber to about 0.8-atm. Second, we filled the chamber withpure N2 gas (no concentration of Rn) to 1-atm. Third, we measured yields of alpha particles. By repeatingthese processes, we obtained the yields of detecting alpha particles for various Rn density in the chamberwith 1-atm. Results are shown in Fig. 2. We made sure that we could measure the Rn-flux by filling thechamber with various atmosphere.
References[1] T. Iizuka, M. Aida and Y. Tagishi, UTTAC annual report (1999) 33- 51 -

Yields of Į particles per hour divided with the pressurein the chamber (counts)

4000

3000

2000

1000

0
0

0.2

0.4

0.6

0.8

1

Pressure in the chamber (atm)Fig. 1.

Relation between various pressures in the chamber and the corresponding yields of alphaparticles with energy of 6.003 MeV divided with pressure in the chamber.

Yields of alpha particles (counts/hour)

20000

15000

10000

5000

0
0

0.2

0.4

0.6

0.8

1

Relative contens of Rn-flux

Fig. 2.

Relation between the density of 222Rn-flux and yields of alpha particles from 218Po.

- 52 -

3.1

Resonant ionization of channeled dressed ions in a crystal field

H. Kudo, K. Takeda, W. Iwazaki, T. Suguri, C. Sakurai, S. Numazawa, I. Arano, S. Seki1
When partially ionized (“dressed”) ions are incident on solids, some of the bound electron(s) of theions are stripped when the input charge is lower than the equilibrium charge in the solid, which depends
mainly on the velocity of the ions. The released electrons are referred to as loss electrons. The kinetic
energy of the loss electrons are distributed around the loss-peak energy EL , which is equal to the kinetic
energy of the electron moving at the same speed as the ion. We have recently measured loss electrons
emitted from crystal targets. The aim of the study is to observe the resonant ionization as a result of
the resonant coherent excitation (REC, or the Okorokov effect) due to a periodical electrostatic field in a
crystal lattice. Technically, this is the first attempt to observe REC in a backward direction, in contrast
to the transmission experiments or specular-reflection measurements so far adopted for the REC studies.
[1, 2, 3]
The C4+ and C6+ beams in the MeV/u energy range were obtained at UTTAC. The electron energy
spectra emitted from Si and Ge crystals were measured at 180◦ with respect to the beam direction [4],using the 45◦ parallel-plate spectrometer of the double deflection type under the pressure of ∼3×10−7 Pa.
This layout has a characteristic feature that the continuum energy spectrum is independent of the tilt angleof the target surface.

Yield (counts)

4.0 MeV/u C

(a)

20000

Si

C4+

16000

C6+

12000
Random
8000

C4+
C6+

<110>

4000
0

0

1

2

3

Electron energy (keV)(b)

Yield (counts)

50000

3.5 MeV/u C

40000
C6+

Ge

C4+

30000
Random

20000
10000
0

C4+

C6+

0

1

<110>

2

3

Electron energy (keV)

Figure 1: Energy spectra of secondary electrons emitted from Si and Ge, bombarded by the dressed andfully-stripped ions.
Figure 1 shows energy spectra of the secondary electrons induced by 3.5 and 4.0 MeV/u C4+ andC6+ for 110 and random incidence on Si and Ge crystals. The electron yields are normalized to a same
number of the incident ions. Each pair of the spectra in Fig. 1 are shown so that the yields in the highenergy side (3.0–3.5 keV) are the same. Indeed, the high energy side of the observed spectra for C4+ andC6+ are overlapped typically within an uncertainty of ±10%. Since EL = 1.91 and 2.18 keV for 3.5 and
4.0 MeV/u C ions, respectively, the measured spectra cover most of the electron energy range to which theloss electrons contribute.
The fully stripped C6+ hardly capture target electrons and, therefore, the electron yield results mainly
from the binary-encounter processes between the ion and target electrons. Accordingly, we may assume
1 SSL Tsukuba- 53 -

that the loss electron yield is approximately given by the difference between the yield for C4+ and C6+ inFigs. 1(a) and (b), respectively. It should be noted that there is a cross point at 0.5–0.8 keV in each pairof the spectra for 110 and random cases. Furthermore, the cross-point energy is slightly higher for the
110 than for the random case. This is due to the lower production cross sections of the binary-encounterelectrons for C4+ than for C6+ in soft collisions with target atoms. Actually, in the low-energy limit of theelectron energy, the ratio of the cross sections for C6+ to C4+ can be roughly estimated as (6/4)2 = 2.25,
from the projectile-charge dependence of the production cross section of binary-encounter electrons [5].
The production cross section of the low-energy electons should be lower for the channeling case since soft
collisions are dominant in contrast to the random case, which gives rise to the higher cross-point energy
than in the random case.
6000
Loss yield (counts)

4.0 MeV/u C on Si
5000
4000
Random
3000
2000
<110>
1000
0

1.0

1.2

1.4

1.6

1.8

2.0

2.2

2.0

2.2

Electron energy (keV)
Ratio of <110> to random loss yield

1.2
1.0
0.8
0.6
0.4
0.2
0.0

1.0

1.2

1.4

1.6

1.8

Electron energy (keV)

Figure 2: Energy spectra of the loss electrons (top), and the ratio of the loss yiled for 110 to the randomcase (bottom).

Figure 2 shows energy spectra of the loss electrons, i.e., the C4+ yield subtracted by the C6+ yield,
and the ratio of 110 to random loss yield. The ratio is 0.5-0.6 in the energy range 1.0–2.0 keV inconsideration. This value is consistent with a previous work [4], in which it was concluded that C4+
typically loses 1 electron when it is channeled, while ∼2 electrons are lost in the random case.
Axially channeled ions experience periodic electric field with a frequency of v/d, where v is the ion
velocity and d is the atomic spacing along the axial direction. RCE is therefore expected to occur whenthe electron excitation energy of the dressed ions, ∆E, satisfies ∆E = Nv/d (N = 1, 2, 3, ...).
In the present analysis, the electron yield was integrated in the energy range where the electron yieldfor C4+ is greater than for C6+ , as seen in Fig. 1. The relative loss electron yield is defined by the
integrated loss electron yield divided by the integrated C6+ yield. Fig. 3 shows the dependence of therelative loss electron yield for Si 110 on the incident ion energy. We see that the relative loss electron
yield increases sharply at ∼3.5 MeV/u with increasing the ion energy. This value is in good agreementwith the resonance energy of 3.44 MeV/u, corresponding to the 1s to 2p transition (∆E = 277.4 eV) of
C4+ under the RCE condition for d = 3.84 Å (Si 110 ) and N = 1. The observed sharp increase of theloss electron yield is attributed to the enhanced ionization of the excited 2p electron, resulting from thedecreased binding energy (283.8 down to 6.4 eV) and the widely spaced distribution of the 2p electron,
compared with the 1s electron.
In further studies of RCE in a backward direction, planar, rather than axial, RCE would provide
detailed resonance profiles. Planar RCE can be measured by tilting the crystal along a planer direction- 54 -

0.30

Relative loee-electron yieldC4+

Si<110>0.25
0.20
Random0.15
0.10
RCE (1s to 2p)
0.05
0

2.0

RCE (1s to n=
2.5

3.0

3.5

4.0

)
4.5

Ion energy (MeV/u)

Figure 3: Dependence of the relative loss electron yield for Si 110 on the ion energy.

of interest [1]. Angular dependence of the loss electron yield is typically easier to measure than the
projectile-energy dependence obtained in the present experiments. Measurements of planar RCE by thepresent observation technique are now being planned to develop a new technical approach to RCE.

References[1] H. F. Krause, S. Datz, Adv. At. Mol. Opt. Phys. 37 (1996) 139.
[2] K. Kimura, H. Ida, N. Fritz, M. Mannami, Phys. Rev. Lett. 76, (1996) 3850.
[3] C. Auth, H. Winter, Phys. Rev. A 62 (2000) 012903.
[4] H. Kudo, Ion-Induced Electron Emission from Crystalline Solids, ’Springer Tracts in Modern
Physics, vol. 175’, Springer-Verlag, Berlin, Heidelberg, 2002.
[5] M. E. Rudd, Y. -K. Kim, D. H. Madison, T. J. Gay, Rev. Mod. Phys. 64 (1992) 441.

- 55 -

3.2

Electron emission from Si crystals bombarded by fast Ag ions

H. Kudo, M. Nagata, M. Suzuki, I. Arano, S. Numazawa, C. Sakurai, W. Iwazaki, T. Suguri, S. Seki1
When solids are bombarded by ions in the MeV/u energy range, most of the energetic electrons emitted
from the surface are produced originally in the binary-encounter processes [1]. Studies of ion-induced
electron emission under channeling incidence conditions of fast ions have so far been reported for ions ofatomic numbers Z1 up to 17 (35 Cl) [2, 3]. It is of fundamental interest to investigate whether the present
understanding of the phenomenon still holds for projectile ions of much high Z1 values. In response to theabove question, the present experimental work provides data for high Z1 , using Ag ions (Z1 = 47).
We have studied energy spectra of electrons emitted from Si and Ge single crystals bombarded by
1 MeV/u Ag ions under channeling and nonchanneling (random) incidence conditions. The electrons were
measured at 180◦ with respect to the ion beam direction. Detection of electrons at 180◦ is advantageous
for the purpose of avoiding errors associated with misalignment of the spectrometer.
The experimental conditions were similar to those reported elsewhere. Figure 1 shows energy spectraof secondary electrons emitted from Si and Ge bombarded by 1 MeV/u Ag10+ and Ag11+ under 110 and
random incidence conditions. In this case, the binary-encounter peak energy EB is 2.18 keV. We see in

105

104
RANDOM
10

3

102

10

1MeV/u Ag11+ on Si

1MeV/u Ag10+ on Si

Yield (counts)

Yield (counts)

105

<110>

1

2

104

RANDOM
10

3

102

10

3

105

10

2

<110>

3

1MeV/u Ag11+ on Ge

Yield (counts)

Yield (counts)

10

3

2

105

1MeV/u Ag10+ on Ge

RANDOM

1

Electron energy (keV)Electron energy (keV)

104

<110>

RANDOM

104

<110>

1

2

10

3

Electron energy (keV)

3

1

2

3

Electron energy (keV)

Figure 1: Energy spectra of secondary electrons emitted from Si and Ge bombarded by Ag10+,11+ under
110 and random incidence conditions.
Fig. 1 that the channeling yield differs remarkably from the random yield at electron energies higher thanEB = 2.18 keV. This difference is due to shadowing of Si L-shell electrons, and of Ge M-shell electrons,
as pointed out previously. Furthermore, there is no essential difference in the yiled for Ag10+ and Ag11+ .
The ratios of 110 to random yield, i.e., the normalized 110 yields are shown in Fig. 2. We may
compare the values of the Si 110 normalized yield W0 at an electron energy of ∼ (EB + EL )/2, with EL
being the loss-peak energy, with the previously measured values for the equal-velocity He2+ . The valueof W0 = 0.78 ± 0.04 for Ag10+ and Ag11+ is greater than W0 = 0.59 ± 0.02 for He2+ , by a factor of 1.3.
This difference is due the screened neclear charge of the Ag ions, since in this velocity range roughly 50%of the total electrons of Ag are in the bound state (charge state 25+) in solids [4]. Screening of the nuclear
1 SSL Tsukuba- 56 -

1MeV/u Ag10+ on Si

1

Normalized <110> yield

Normalized <110> yield

charge of the ion gives rise to the enhanced normalized yield by (i) the reduced shadowing effect, and (ii)the enhanced recoil effect, according to previous works [3].

0.8
0.6
0.4
0.2
1

2

1

0.6
0.4
0.2

3

0

1MeV/u Ag10+ on Ge

0.8

0.6

0.4
1

2

1

2

3

Electron energy (keV)

Normalized <110> yield

Normalized <110> yield

Electron energy (keV)

1

1MeV/u Ag11+ on Si

0.8

1

0.9

0.8

0.7

0.6

3

1MeV/u Ag11+ on Ge

0

1

2

3

Electron energy (keV)Electron energy (keV)

Figure 2: Normalized 110 electron yields for Si and Ge.

The experimental results are summarized as follows:• The present work demonstrates that even for high-Z1 projectiles, such as Ag, the energy spectraof ion-induced electrons emitted from crystals can be accounted for in terms of the high-energy
shadowing effect on specific inner-shell electrons of the crystal atoms.
• For high-Z1 ions, screening of the projectile nucleus by the bound electron(s) is a key factor forunderstanding the degraded shadowing effect compared with that for highly ionized ions.

References[1] M. E. Rudd, Y. -K. Kim, D. H. Madison, T. J. Gay, Rev. Mod. Phys. 64 (1992) 441.
[2] H. Kudo, A. Tanabe, T. Ishihara, S. Seki, Y. Aoki, S. Yamamoto, P. Goppelt-Langer, H. Takeshita,and H. Naramoto, Nucl. Instr. and Meth. B 115 (1996) 125, and references therein.
[3] H. Kudo, Ion-Induced Electron Emission from Crystalline Solids, ’Springer Tracts in Modern
Physics, vol. 175’, Springer-Verlag, Berlin, Heidelberg, 2002.
[4] K. Shima, N. Kuno, M. Yamanouchi, H. Tawara, At. Data Nucl. Data Tables 51 (1992) 173.

- 57 -

3.3

Anomalous elastic property of nanocrystalline gold

H. Tanimoto, Y. Koda, T. Yamada, S. Sakai, H. Mizubayashi,
Institute of Materials Science, University of Tsukuba
1. Introduction
When the ultrafine particles are mechanically consolidated, the disordered grain boundaries(GBs) can be formed to accommodate the neighboring ultrafine crystallites.

Characteristic

properties of the nanocrystalline (n-) metals prepared through such an athermal root may be
associated with the disordered GBs as well as an increased volume fraction of the GB regions [1].
By the progress in thecnique, the n-metals with the density more than 98 % of the bulk density havebeen prepared.

Surprisingly, the moduli measured for the pore- and contamination-free n-metals arefound to be very close to those of the conventional polycrystalline (p-) metals, suggesting that the
local density of the GB regions in the n-metals are not so different from the bulk density [2-4].

Onthe other hand, very recently, the interesting anelastic response is found for the high-density n-metals.
For n-Au specimens prepared by the gas deposition method, the strong anelastic strain due to a certain
GB process can be observed above 200 K [5].

In order to modify the GB state and to survey thechange in the elastic property, anelastic measurement was conducted for the high-density n-Au
irradiated by electron at

low-temperature.

2. Experimental Procedure
The high-density n-Au specimen was prepared by the gas-deposition method [4].

The meangrain size and the density of the specimen used were about 20 - 25 nm and more than 99 % of the pAu, respectively.

The 20MeV proton irradiation was carried out by using the tandem accelerator of

University of Tsukuba.

The 2MeV electron irradiation was carried out at 10 K by using the 3MeV

single-ended electrostatic accelerator of TIARA, JAERI. The anelastic measurement was performedby the flexural vibrating-reed method, where the resonant frequency, f, andinternal friction, Q-1,

were measured by using the specially designed cryostat during and after irradiation.
3. Results and Discussion
Figure 1 shows the strain amplitude, ε, dependence (SAD) in the modulus observed for n-Au
before and after 2MeV electron irradiation. It is noted that f2 is proportional to Young’s modulus, E.
In the ε range in between 10-6 to 5 x 10-3, E typically shows a decrease by about 1 % with increasing ε
up to ~ 1 x 10-3, and then turns to increase for ε above ~ 1 x 10-3 showing a saturation at ε ~ 5 x 10-3
(not shown here).

It is noted that the internal friction, Q-1, shows a slight increase for ε below ~ 1 x

10-3 and then a steep increase for ε above ~ 1 x 10-3.

No change was observed for these unique SAD

of n-Au after 2MeV electron irradiation.
On the other hand, a large increase in f was found during the low-temperature irradiation.
Figure 2 depicts the normalized change in f at 6 K observed during the irradiation, where the Frenkel-- 58 -

pair concentration was estimated from the electron dose.

It is known that the modulus shows a slightdecrease by the accumulation of the radiation defects (the bulk effect), and its rate per unit Frenkelpair concentration is reported to be about -10 for the low-temperature electron irradiation of refractory
BCC metals [6].

The increased f by the irradiation showed a recovery by about 50 % after warm-up

to room temperature.

The features observed for the anelastic measurements of n-Au were quite same

between the 2MeV electron irradiation experiment and 20 MeV proton irradiation experiment.
These results indicate that the radiation defects would be trapped at the GBs in n-Au and modify
their state as leading to the large increase in the modulus at 6 K.

In contrast, the SAD of themodulus is independent on the radiation defects probably trapped at the GBs. We surmised that the
SAD of the n-Au might reflect the characteristic of the crystallites in the n-Au rather than that of theGBs.

A further study is now in progress.

References[1]

H. Gleiter, Prog. Mater. Sci. 33(1989) 223.

[2]

P. G. Sanders, J. A. Eastman and J. R. Weertman, Acta Mater. 45(1997)4019 : P. G. Sanders, C.

J. Youngdahl and J. R. Weertman, Mater. Sci. Eng. A234-236(1997)77.
[3]

X. Y. Qin, X. R. Zhang, G. S. Cheng and L. D. Zhang, Nanostruct. Mater. 4(1998)661.

[4]

S. Sakai, H. Tanimoto and H. Mizubayashi, Acta Mater. 47(1999)211.

[5]

S. Sakai, H. Tanimoto and H. Mizubayashi, Scripta Mater., 45(2001) 1313.

[6]

H. Tanimoto, H. Mizubayashi, R. Masuda, S. Okuda, T. Iwata, H. Takeshita and H. Naramoto,phys. stat. sol. (a), 132(1992)353.
f_strain.smp

f(normalized)_fp.smp[×10-3]at 6 K

6n-Au( f - f0) / f0

E / E0

before irrad. (at 295 K)

83 ppm irrad. (at 6 K)
1%

4
2

300 K annealed after 83 ppm irrad. (at 6 K)

0bulk effect for polycrystalline metals

300 K annealed after 83 ppm irrad. (at 295K)

0

10

0

20

20

40

60

80

Frenkel-Pair Conc., CFP /

ppm

-5

Strain Amplitude / 10

Figure 2.
Change in the resonant
frequency, f, observed during lowtemperature 2MeV electron irradiation,
where f2 is proportional to E. For thecomparison, the bulk effect observed forthe polycrystalline metals is also shown.

Figure 1. Strain amplitude dependence in
the Young’s modulus, E, observed for n-Au
before and after electron irradiation. E0 is
the E observed at the smallest strain.

- 59 -

3.4

Fabrication of microstructures in rutile TiO2 single crystal using
structural change induced by swift heavy-ion bombardment

M. Fujimaki1, K. Awazu1, N. Kobayashi1, T. Nakanishi2, K. Nomura2, Y. Ohki2, S. Ishii and K. Shima

It is known that a latent track, which is heavily damaged cylindrical zone, is made by the passage
of swift heavy ions in many insulators. A visible hole is observed at the latent track by etching done after
ion bombardment, because of an enhanced etching rate at the track [1]. Since this phenomenon has apossibility to fabricate micro- or nano-structures in an insulator, further investigation has been carried out.
Titanium dioxide (TiO2) is a well-known insulator and is attracting much attention because it has
many ways of applications in optics and electronics. For example, it is used as a catalyst, an opticalprism, an isolator and as a photonic crystal.

A photonic crystal, which has a spatially periodic

permittivity modulation, realizes several valuable photonic devices such as a super-prism, a sharp-bend
optical waveguide, and a high-Q cavity.

Therefore, we used rutile TiO2 single crystal as a sample andhave tried to establish the methods of fabricating micro- or nano-stractures into the sample.
The rutile TiO2 single crystals used have a purity higher than 99.99 %, density of 4.25 g/cm3 andplane index of (100). They were synthesized by the Verneuil flame-fusion method and were supplied by
Nakazumi Crystal Laboratory.
500 µm.

They were cut into plates and epitaxially polished to a thickness around

Their root-mean-squared roughness is less than 0.8 nm.

Ion irradiation was carried out using a

12-MV tandem accelerator at the University of Tsukuba Tandem Accelerator Center (UTTAC), in a
vacuum with a residual pressure below 1 È 10-3 Pa at room temperature.

To survey the surface

morphology and the structural changes after the ion bombardment, we used a scanning electron
microscope (SEM, Hitachi S-2500CX), a high-resolution electron microscope (HREM, Hitachi
H-9000NAR) and an X-ray diffractometer (Rigaku FR-MDG).

A mask was put on the sample to restrict

the irradiated area during the ion bombardment. The step height was measured between the irradiatedarea and the non-irradiated area with a DEKTAK II A profilometer, where the experimental error was ±10 %.

For etching, we used hydrofluoric acid.
We irradiated ions to the sample to a dose over 5.0È1013 cm-2. The ions irradiated are 120-MeV

I11+, 40-MeV I7+, 120-MeV Br11+, 50-MeV Br7+, 110-MeV Cu10+, 84.5-MeV Cu17.4+, 15-MeV Cu10.6+, and100-MeV Ti10+. When the step height between the irradiated and non-irradiated areas was measured, an
expansion was observed in the irradiated area for all the ions we used. Since the density of rutile phase is
the largest among the crystal phases of TiO2, it is considered that this expansion is caused by a structuralchange.

12Figure 1 (a) shows a SEM picture of the surface step between the irradiated area (lower right)

National Institute of Advanced Industrial Science and Technology (AIST)
Waseda University- 60 -

and the non-irradiated area (upper left) after the surface was etched following the irradiation of 110-MeV
Cu10+ ions to a dose of 8.0È1013 cm-2.

The irradiated area was etched to a depth of 8.1 µm, while

non-irradiated area was not etched at all, regardless of the hydrofluoric acid concentration. The depth
does not get deeper even when the etching time or dose increases. This tendency was seen for all theions examined. It should be also noted that the etched surface is very flat and the roughness of theboundary wall, which was formed by etching, is very small as shown in Fig. 1 (a).

Figures 1 (b) and (c)are the SEM pictures of the surface which was etched after it had been irradiated by 110-MeV Cu10+ ionsto a dose of 8.0È1013 cm-2 through a 13-µm thick gold mesh. The mask shapes were properly transcribedon the rutile TiO2 single crystal.

By using this technique we can fabricate micro- or nano-structures indielectric materials such as a rutile TiO2 single crystal.

(a)

(b)

(c)

8.1 µm

20 µm

20 µm

100 µmFig. 1. SEM pictures of the TiO2 surface etched by 20 % hydrofluoric acid for 30 min.

Irradiation with 110-MeV Cu10+ ions to adose of 8.0 × 1013 cm-2 had been done on the sample prior to the etching through a 1-mm thick silicon plate masking the upper left
area during the irradiation (a) or through a 13-µm thick gold mask [(b) and (c)].

References[1] K. Awazu, S. Ishii, K. Shima, S. Roorda and J. L. Brebner, Phys. Rev. B 62, 3689 (2000).

- 61 -

3.5

Measurement of retained deuterium density in metals after deuteron
implantation

N. Kawachi, N. Yoshimaru and Y. Tagishi
We have developed a new method of measurements of implanted deuterium atoms by observing
emitted protons from the nuclear reaction 2H(d,p)3H between implanted deuterium atoms and incident
deuterons [1]. A drastic difference in the time dependence of the proton yield was observed between single
and polycrystalline targets [1]. We made measurements to estimate the density of deuterium atoms after
deuteron implantation. It is difficult to obtain the density of deuterium atoms near the mean penetration
with the method described in the paper [2], because the cross section of the reaction 2H(d,p)3H near therange is too small for calculating correctly the concentration of deuterium atoms.
Experiments were performed with the same experimental setup as described in [2] using two
deuteron beams with energies of 100 keV and 50 keV at UTTAC. Samples for the implantation were
single and polycrystalline targets of tantalum, palladium and copper. A method for estimating the
distribution consists of the following three steps.
Step 1. (deuteron implantation at 50 keV): A target was prepared by deuteron implantation at an energyof 50 keV in an area of 3 mm in diameter. The implantation flux was approximately 2 × 1013 D/cm2⋅s.
Approximately 6 × 1017 D/cm2 deuterons were implanted in the target material.
Step 2. (irradiation of analyzing beam at 100 keV): After the implantation, a deuteron beam with ahigher energy of 100 keV was delivered to the target material. A slit of 1 mm in diameter was placed todefine a smaller irradiation area in the center of the implanted area in step 1. In order to switch thedeuteron beam energy from 50 keV for implantation to 100 keV for analysis, the irradiation wasinterrupted for a short time (~ 400 s). The dose delivered by the analyzing beam was 6 × 1015 D/cm2,
which was large enough to obtain an adequate number of emitted protons for analysis of implanted
deuterium atoms.
Step 3. (evaluation of deuterium atoms implanted at 100 keV): The protons detected in Step 2 includes
not only protons which were emitted from the 2H(d,p)3H reaction with deuterium atoms implanted in
Step 1 at 50 keV, but also from protons caused by implanted deuterium atoms during Step 2 at 100 keV.
To subtract the proton yield from the irradiation at 100 keV, the same dose of 6 × 1015 D/cm2 wasirradiated on the same size as the virgin material. The energy spectrum of the emitted protons from thisarea was subtracted from the spectrum obtained in Step 2. The distribution of deuterium atoms
implanted at 50 keV was derived with this substraction.
The number of emitted protons in Table 1 is proportional to trapped and retained deuterium atoms intarget metals. This result supports the reported data in [1], where a large difference of emitted proton
yields between single and polycrystalline Ta and Pd target is obtained and no difference in case of those in
Cu. It is clear that the number of retained deuterium atoms appears to the time dependence of the proton
yields and there are little deuterium atoms trapped in single crystal Ta.
Deuterium atoms are possible to solute into both Ta and Pd single and polycrystalline metals because- 62 -

of its minus enthalpy. The accumulating deuterium atoms should be sensitive to the number of deuterium
trapping with impurities. It is difficult to discuss to what extent the difference of the time dependence ofthe proton yield is caused by deuterium atoms trapped with impurities in metals. Only a difference of
tantalum single crystal impurities between <100> and <111> could be checked with catalog data. It
considered being due to appear the difference of the retained deuterium atoms in the <100> and the <111>
Ta single crystal. Copper has plus enthalpy to hydrogen solution at infinite dilution, so that the implanted
deuterium atoms cannot exist stably. However, radiation damage should be produced at near surface
region in case of both single and polycrystalline target. The damage might play some role on similar yield
curves of emitted protons, which indicates the same concentration of deuterium atoms in single andpolycrystalline Cu.
References[1] N. Kawachi et al. UTTAC annual report 69(2000)59[2] N. Kawachi, T. Katabuchi, et al. Nucl. Instrum. Methods Phys. Res. B 190(2002)195

Poly-crystal

Single crystal
<100>
<111>

335
308

Tantalum

13296 (count)

Palladium

6357

3725

Copper

15789

14441

Table 1 The number of emitted protons from the implanted targets with 50 keV deuterons, using a probe
beam of 100 keV deuterons. This number indicates the trapped and retained deuterium atoms in
the target metals.

- 63 -

3.6

TOF spectra of dissociated molecules by photon/HCI impact incrossed-beam apparatus for cluster fission experiment

H. Sasaki, Y. Takanashi, M. Imanaka, I. Arai and S. M. Lee
We have developed a TOF mass spectrometer system to measure the mass to charge ratio of the products generated by collision between a highly charged ion(HCI) and a neutral molecule or cluster. In thisreport, we introduce this system and show preliminary spectra of collision products observed with benzene
target irradiated by laser and HCI.
A schematic view of the system is illustrated in Fig. 1. The HCI beam is provided from an electron
cyclotron resonance ion source[1] and separated according to mass to charge ratio by the 90 degree analyzer magnet. We used a Xe20+ beam extracted by a voltage of 15 kV the current of which was 1 µ A.
The charge selected beam is chopped into a pulsed beam with a time duration of 200 ns long by a pulsing
electric field generated by the deflecting electrode. To make a pulsed high voltage swing from 0 V to 2.8
kV on the electrode, we use a high speed push-pull switch(Bhelke Electronic, HTS31-GSM). The pulsed
ion beam passes through the diaphragm of φ 1 mm and intersects the target chamber. The base pressureof the target chamber is 10−8 torr. We put the benzene vapor into the target chamber up to the pressureof 1.0×10−6 torr. The extraction region consists of an ionization region and acceleration region. After a
HCI beam has passed the ionization region, an extraction field can be pulsed with a high speed push-pull
switch and the ions of collision products enter the acceleration region. In the acceleration region there areapplied two electric field with different gradients from each other. The two stage extraction can focus theflight time of the ion which was produced with the same m/q but at the different position in the ionization
region. An acceleration voltage of 2700 V is applied in a region of 5 cm in length giving a field gradientof 107 V/cm for the first acceleration region, while the same voltage is applied in a region of 4 cm giving afield gradient of 525 V/cm for the second acceleration. The intermediate electrodes (1 cm apart from eachother) in the acceleration region ensure a good homogeneity of electric field necessary for a high mass
resolution. The path of the ions is corrected by the electrostatic steerer and focused by the Einzel lens.
The ions fly in the field free region of 2 m and finally go into the detector. We used a micro channel plate
detector with a cup-type electron conversion dynode. We measured TOF spectra by using a trigger signalof the extraction pulse switch as a start signal and an output signal of the detector as a stop signal, both ofwhich were lead to a 2 GHz multi-stop time to digital converter(P7886E, FAST ComTec).
Fig. 2 shows the result obtained in collision with highly charged Xe20+ ions. There are the clearly
identified peaks of benzene +1, +2, +3 in addition to those of residual gas ions. This fact seems to suggestthat benzene is produced in highly charged states with relatively low internal energies. In Fig. 3 is shown
the spectrum, where benzene have been irradiated by a YAG laser(4th harmonics, photon energy:4.67
eV). The mass resolution estimated from a peak of benzene +1 is about 1000. It is found that only singly
charged ions are produced. The series of dominated peaks for Cn H+
m ions is thought to be caused in thecourse of evaporation process of parent hydro-carbons with an increased internal temperature.
Now, we are planning to produce a highly charged cold metal cluster and measure its appearance sizeand fission pattern[2].

References[1] T. Kurita, Doctor thesis, University of Tsukuba(2001).
[2] F. Chandezon, S. Tomita, D. Cormier, P. Gübling, C. Guet, H. Leibius, A. Pesnelle and B. A. Huber,
Phys. Rev. Lett. 87, 153402(2001).

- 64 -

from ECRIS
90˚ magnet

steerervariable
diaphragm
einzel lensdiaphragm(φ3)

ToF spectrometer

extract electrodeeinzel lens

steerer
CaF2 window

e-converter
MCP

lens

YAG laser

mirror0500

1000 mmFig. 1: Top view of beam line and TOF system

Yield(a.u)

3000
N2+

2000
1000

C6Hn2+C6Hn+

C6Hn3+
+

H2O
N+

0
0

O2+

20

40

60

80

100

m/q

Fig. 2: Mass/Charge distribution of collision products observed with benzene molecule irradiated by
Xe20+ .

Yield(a.u)

800

C+

C2Hn+

600

C3Hn+

C4Hn+

C6H6+

60

80

400
200
0
0

20

40

100

m/q

Fig. 3: Mass distribution of benzene molecule and its fragment irradiated by a YAG laser. The fluence oflaser pulse is 4 mJ/pulse, its pulse width is 4 ns and its spot size is below 1 mm.

- 65 -

3.7

Cluster abundance spectra of low melting temperature metals produced by bombardment of 6keV Xe atoms

T. Miyazaki, K. Teranishi, H. Sasaki, I. Arai and S.M. Lee
In the previous experiments on sputtering of high melting temperature transition metals with
6keV Xe atoms, we observed that cluster abundance spectra for such metals typically show a
power law nature. We successfully described the observed regularities shown via such a power law
nature in the cluster abundance spectra with use of a model based on the following assumptions;(1)thermal diﬀusion along the surface, (2)associated formation of thermally isolated area, theequilibrium temperature being kept much higher than the melting temperature at around thebombardment position, and (3)cluster formation within the thermally isolated area as a resultof bond-breaking. Furthermore, a strong correlation between the broken bond probability p, i.
e., an only parameter in the model calculation, and the melting temperature for each metal was
also reproduced well. However, it was found that the model is not applicable in cases of themetals such as Zn and Mn. The cluster abundance spectra for those metals were expressed byexponential functions quite well. So far, an exponential function-like spectrum was thought to be
characteristic in the early stage of gaseous aggregation process. Therefore, it is suggested that ahuge number of monomer atoms are released by a certain kind of explosion on the surface [1][2][3].
In the present experiment, we have carried out the same measurements for the low melting
temperature metals In, Ga, Sn and Bi and discovered other types of cluster abundance spectrathan the previously observed ones. One is expressed by a combination of an exponential function
and a power function in the case of In and Ga(see Figure 1), and the other by a combination ofan exponential function and a log-normal function in the case of Sn and Bi(see Figure 2).
In the former case, it is expected that an explosive release of monomer atoms occurs justafter the bombardment and the cluster formation proceeds via monomer absorption at some laterstage. More than 90 % of secondary cations seems to originate in this process and most of thermalenergy given by the bombardment of Xe atom is released as well. The exponent of power function
is found to be -1.5, which should be compared with the value of -2.7 in the case of high melting
temperature metal such as Cu. In other words, larger-sized clusters are produced in this casethan in the case of Cu. A possible scenario is as follows;(1)an explosive monomer production
takes place at ﬁrst and (2)a cluster formation via bond-breaking happens on the remnant surface
in succession. The temperature of remnant surface should become lower than the one in the casewithout such an explosive monomer production. The considerable energy is released prior to athermal equilibrium. As a result, the broken bond probability p becomes small comparatively.
In the latter case, the observation of spectra following to log-normal functions is substantiallynew. Such spectra is rather common to a cluster formation via cluster coalescence under thecourse of aggregation process in high density gaseous environment, which is unlikely to occur ina singly driven short time phenomenon such as sputtering. If the underlying process is similar toan aggregation process, the present observation suggests a explosive release of monomer atoms
with a high density core.
Figure 3 shows a correlation between a melting temperature and a variable corresponding
to a evaporative latent heat, i.e., a ﬁrst order coeﬃcient in the T1 expansion of saturated vapor
pressure. The cluster abundance spectra for the materials with higher melting temperature seemto be expressed by a power function, while those for the materials with smaller evaporative
latent heat by an exponential function. In the lower melting temperature region, those for thematerials with larger evaporative latent heat show an intermediate nature, i.e. a combination ofan exponential function and some other function, i.e., a power function or a log-normal function.

- 66 -

10

Abundance

10
10
10
10
10
10

6

Ga
T=303[K]

5

4

3

2

1

0

2

4

6

8 10 12Cluster Size

14

16

18

Fig. 1. Abundance spectrum of Ga clusters produced by bombardment of 6keV Xe atoms, whichis represented by a combination of an exponential function and a power function(solidline).

References[1] I. Arai, Desorption 2000 Int. Conf., Saint Malo, France, 3-7(2000), invited talk.
[2] I. Arai et al., Trans. Material Research Society of Japan, 26, (2001) 1139.
[3] I. Arai et al., Trans. Material Research Society of Japan, 27, (2002) 193.

- 67 -

10

Abundance

10
10
10
10
10
10

4

Sn

3

2

1

0

-1

-2

2

4

6
8
10
Cluster Size

1214

Fig. 2. Abundance spectrum of Sn clusters produced by bombardment of 6keV Xe atoms, whichis represented by a combination of an exponential function and a log-normal function(solidline).

- 68 -

coefficient A (latent heat) [Pa K]

50x10

3

Ta

W

Nb

40
Fe,Co,Ni

Mo

30
Ti

20

Ga Sn
In

10

Cu

Al

V
Cr

Mn

Bi

Zn

0
0

1000

2000

3000

4000

Melting Temperature [K]Fig. 3. Correlation between a melting temperature and a variable corresponding to an evaporative latent heat for each element, the spectrum of which is expressed by (1)power function(circles), (2)exponential function(triangles), (3)combination of an exponential function
and a power function(diamonds) and (4) combination of an exponential function and alog-normal function (squares).

- 69 -

3.8

Simulations on gold and copper clusters

T.X.Li, I.Arai and S.M.LeeThe knowledge of structural and thermodynamic properties of ﬁnite atomic system is essential to the application of clusters and cluster-assembled materials. By using molecular dynamic
simulation,we studied the solid-solid transitions and coalescence of gold and copper clusters.
Dynamic simulations on Au55 reveal the solid-solid structural transitions among diﬀerent
symmetric conﬁgurations, from cube-octahedron to icosahedron and disordered structure, at certain temperatures below the melting point. The latter deformation had not been demonstrated
in earlier simulations on small clusters. However, Krakow and his colleagues found in their
HRTEM(high resolution transmission electron microscope) study that supported gold clusters
less than 10A* in size of ten appear to be disordered[1] .The solid-solid transformations are microscopically demonstrated as processes of collective distortion of atoms and migration of partial
atoms. In both cases the cohesive energies of the system go smoothly without any signiﬁcantbarrier during transitions. This result has been sent to some journal for publication.
Multiply twinned particles(MTP) are frequently observed under HRTEM for metal nanoparticles[2].
Our simulation on Cu clusters shows this may because of the thermal stimulation in acouple ofsticked clusters.
We use a Gupta-type many body potential to describe the interaction among the atoms. As
a function of interatomic distance rij , the potential is expressed as

V

=

n

j=1



A

n




exp[−p(rij /r0n − 1)] − ξ 2i(=j)=1n1/2 

exp[−2q(rij /r0n − 1)] i(=j)=1

In present work, the parameters for Cu are set as A=0.0855, ξ =1.224, p=10.96 and q=2.278,
which have been ﬁtted for bulk copper[3]. Two clusters, Cu38 and Cu75 initially have truncatedoctahedron and quasi-crystalline as their most stable structure respectively, are approached toeach other and heated up step by step. The structure of sticked large cluster is recorded afteralong term relaxation in each step.
Fig.1 shows the structural evolution of Cu38+75 with increasing temperature. The original
shape and struture of both parts are kept very well when they touch each other with zero kinetic
energy(Fig.1a). However, as light warming up to 160K causes much compact connection though
the internal structure of each part remains unchanged ;and besides, the direction of each crystal
has been adjusted to get mached at the interface(Fig.1b). When the temperature is increased toan even higher degree(602K), the two small clusters are reconstructed, as one cansee from Fig.1c,
into a multiply twinned particle.The ﬁnal conﬁguration in our simulation is quite consistent to
the experimental observation of gold cluster( 2nm) irradiated by electron[2].

References[1] W.Krakow et al.,Phys. Rev. B49, 10591(1994).
[2] S.Iijima and T.Ichihashi,Phys. Rev. Lett. 56,616(1986).
[3] F.Cleri and V.Rosato,Phys. Rev. B48, 22(1993).

- 70 -

acbFig. 1. The structures of two copper clusters (N=38 and 75) after attaching each other and being
heated up to a)0K, b)160K and c)602K, respectively.

- 71 -

3.9

Mössbauer Study of α''-Fe16N2 foils prepared by a nitrogen plasma
irradiation method

H.Tokano, K.Niizuma*, Y.Utushikawa*, K.Yano* and E.Kita
In 1972, Kim and Takahashi of Tohoku University reported the synthesis of a polycrystalline film
composed of two phases of α-Fe and α’’-Fe16N2 by using vacuum deposition. From the volume fraction,
they estimated the saturation magnetization of α’’-Fe16N2 to be 2200 emu/cc, which largely exceeds thevalue of Slater-Polling curve[1]. After their announcement, there have been a lot of works to synthesize
the α’’-Fe16N2 by various methods. However, the reported values of the saturation magnetization are
different depending on the researchers and fabrication methods and, hence, the exact value of thesaturation magnetization of α’’-Fe16N2 phase still remains uncertain. Such uncertainty is caused by thedifficulty of forming a large quantity of bulk samples due to the fact that the α’’-Fe16N2 phase exists only
in non-equilibrium state. Therefore, in the present work, we attempted to form bulk samples of α’’-Fe16N2
by nitrogen plasma irradiating method. The analysis by Mössbauer spectroscopy was carried out for theobtained samples in order to discuss the volume fraction and hyper fine field.
Iron nitride foils were prepared by a plasma irradiation method in the atmosphere of N2+30%H2 mixture
gases using polycrystalline iron foils as raw material. The samples were quenched using liquid nitrogen inorder to have transformation to α’’-Fe16N2. Mössbauer spectra were taken with a constant acceleration
spectrometer at room temperature. The least squares fit of the spectra were carried out assuming
Lorentzian line shapes.
Table 1 Mössbauer parameters of Fe-N foils
Samplenoquenched

beforeannealed

after
annealed

site
α-Fe
FeI*
FeII*
FeIII*
Singlet
α-Fe
FeI*
FeII*
FeIII*
Singletα-Fe
FeI**
FeII**FeIII**
Singlet

Hhf
(kOe)
330
293
369
332
291
312
369
330
289
317
400
-

I.S.
(mm/s)
0.0046-0.0682
0.01650.03150.0070-0.07450.13090.0493-0.0504
0.00620.07850.21930.1614-0.0551

Fe sites of the α'-martensite phase.

*Fe sites of the α''-Fe16N2 phase.

***

Nihon University- 72 -

Area
(%)
52.0
4.0
5.6
38.4
60.5
4.3
15.9
7.4
11.9
59.6
11.1
10.6
10.1
10.1

Hhfave(kOe)
204

Ms(VSM)(emu/g)139

Ms(cal.)(emu/g)
135

290

187

190

184

186

324
296
330

Table 1 shows fitting parameters and Figs 1 and 2 show Mössbauer spectra, respectively. The sample
without quenching has a strong paramagnetic subspectrum. Therefore, the subspectrum from α’-nitrogenmartensite, which are originally composed of those from three sites, can be divided only two spectra in the
figure. However, the quenched sample has a weaker paramagnetic spectra and, hence, the spectrum from
α’-nitrogen martensite can be clearly divided three subspectra corresponding to three sites.
After annealed, the spectraum become sharper and the subspectrum from α’’-Fe16N2 can be distinctly
divided to three sites spectra. The volume fraction of α’’-Fe16N2 estimated from the spectrum area ratio is
about 30%. The result of fitting gave hyper fine fields of α’-nitrogen martensite are 291kOe, 312kOe and369Oke for FeI, FeII and FeIII sites, respectively. The average value of hyper fine field, Hhfave, is 324Oke,
which is slightly smaller than that of α-Fe. The values of internal field of α’’-Fe16N2 are 289kOe, 317KOeand 400kOe for FeI, FeII and FeIII sites, and Hhfave becomes 330kOe which is almost equivalent to that of
α-Fe. Obtained results show a similar tendency with those of Takahashi and Shoji[2] and are different
from the giant magnetic moment claimed by Sugita et al[3]. The saturation magnetization, Ms(cal.) was
calculated by the assumption that the hyper fine field is proportional to magnetic moment and the hyper
fine field of 33.0T corresponds to 218emu/g for α-Fe. The Ms(cal.) values of all samples are in good
agreement with those actually measured by VSM. From these results, we conclude that the saturation
magnetization of α’-nitrogen martensite synthesized by our method is almost same with that of α-Fe. It isalso found that the saturation magnetization of α’’-Fe16N2 is slight larger than that of α’-nitrogenmartensite, however, it still remains almost same level with that of α-Fe.
References[1] T.K.Kim and M.Takahashi, Appl.Phys.Lett.,20,492(1972).
[2] M.Takahashi and H.Shoji, J.Magn.Magn.Mater.,208,145(2000).
[3] Y.Sugita,H.Takahashi,M.Komuro,K.Mituoka and A.Sakuma, J.Appl.Phys.,76,6637(1994).
γ-austenite
α-Fe

33.00TFe(I)29.30T

Fe(III)

36.90T

Relative Transmisson

1
0.95
0.9
0.85
-10

0
Velocity[mm/s]

Fig.1 Mössbauer spectrum of an Fe-N foil no quenched.

- 73 -

10

γ-austenite
α-Fe

33.2T
29.1T
31.2T

Fe(I)
Fe(II)
Fe(III)

36.9T

Relative Transmisson

1

0.95

0.9
-10

0

10

Velocity[mm/s]
Fig.2 Mössbauer spectrum of an Fe-N foil before annealed.

γ-austenite
α-Fe
Fe(I)

33.0T
28.9T

Fe(II)
Fe(III)

31.7T
40.0T

Relative Transmisson

1

0.95

0.9
-10

0
Velocity[mm/s]

Fig.3 Mössbauer spectrum of an Fe-N foil after annealed.

- 74 -

10

3.10

Mössbauer study of superconducting YFeSr2Cu2 O6+δ compounds

Y. Hata1 , Y. Mihara, T. Mochiku2 ,J.Suzuki1 , I. Kakeya, K. Kadowaki and Eiji Kita

ρ(T) / ρ( 300 K )

4πM ( x10-2 emu / cm3 )Superconductivity and magnetism are two diﬀerent
ordered states into which substances can condense at
low temperatures and in general these state are inim2(a)ical to one another.Especially ferromagnetism interfere
1severely with occurrence of superconductivity. Recently,
0
RESr2 RuCu2 O8 (RE = rare earth element) system has-1been the focus of considerable work because of their in-2
teresting magnetic and superconducting properties.[1, 2]-3
In the case of GdSr2 RuCu2 O8 , it shows a ferromagnetic
RO +HP 58 atm-4transition at 132 K and bulk superconductivity sets in
RO + HP100 atm-5
RO + HP190 atm
below Tc = 15 - 45 K, depending on the sample preparaHP190
atm-6
tions and it was believed that ferromagnetism coexists
with superconductivity in this compounds.
-7
0
50
100
150
Comparison with these study, the substitution for Cu
T(K)site of YSr2 Cu3 O6+y by Fe ion is interesting, however
5
it was reported that they show poor superconductivity(b)with a small Meissner volume fraction and relatively low
4transition temperature. [3, 4, 5] The distribution of Fe
58 atmion at Cu(2) site may suppress the superconductivity
100 atm
190atmand it have been believed that it is impossible to syn3
thesize superconducting YSr2 FeCu2 O6+y compound.
In this report we explore the possibility of synthesiz2
ing superconducting YSr2 FeCu2 O6+y by reoxidization
annealing and high pressure O2 annealing technique.
1
57 Fe Mössbauer spectroscopy is used to investigate the
distribution and magnetism of Fe ions. YSr2 FeCu2 O6+y
0
0
100
200
300 samples were prepared by the solid-state reaction of stoichiometric mixture of Y2 O3 , SrCO3 , CuO, and Fe2 O3T(K)powders. The mixture was calcined at 900◦ C for 24 h inair, ground, and then pressed into pellets. The pellets
Fig. 1. (a)Thetemperawere sintered at 1000◦ C for 24 h in air. Then the pellets
turedependenceofwere subsequently annealed at 800◦ C for 24 h in N2 ﬂow,
the magnetization of
YSr2 FeCu2 O6+y (sample
at 300◦ C for 24 h in O2 ﬂow, and ﬁnally at 350◦ C for 24
3-5)
under
magnetic
h in high O2 pressure of 58 ,100, and 190 atm. We callﬁeld of 1 Oe.
(Fieldthe subsequent annealing in N2 ﬂow and O2 ﬂow ”recooled curves), (b)The
oxidization annealing”. Some of as synthesized pellets
electrical resistivity data
were directly annealed at 350◦ C for 24 h in O2 pressure
for a YSr2 FeCu2 O6+yof 190 atm without reoxidization annealing.
compounds. (sample 3-5)
Fig. 1(a) shows ﬁeld-cooled magnetization of the suThese data are normlizedwith their resistivity at
perconducting samples obtained at the magnetic ﬁeld
300 K.
of 1 Oe. Superconductivity was observed only in thereoxidized and subsequent high pressure O2 annealed
samples. Temperature dependences of resistivity for superconducting samples are shown in Fig.
1(b). The resistivities are normalized with the values at 300 K of 3.80 × 10−2 , 7.91 × 10−3 , and1
2

Advanced Science Research Center, Japan Atomic Energy InstituteSuperconducting Materials Center, National Institute for Materials Science- 75 -

Relative Transmission

2.15 × 10−2 Ωcm, for sample 3, 4, and 5 , respectively. Superconductivity was conﬁrmed in resistivity. Increasing O2 annealing pressure, the onset transition temperature of superconductivity
increases linearly and approches to 60 K. Semiconducting temperature dependences are observed
above the transition temperature.
Figs. 2(a) - (c) show room temperature Mössbauer
spectra of the samples. The spectrum of sample 1 (Fig.
a) sample12(a)) can be ﬁtted to three doublet and the spectra of
1.00
sample 2-3 (Fig. 2(b) and (c)) can be ﬁtted to two doublets. Isomer shift (IS) relative to Fe metal, quadrupole
0.98
splitting (∆Eq), full-width-at-half-maximum (FWHM),
and subspectra area (%) are summarized in Table 1.
0.96
Similar values of isomer shift and quadrupole splitb)
sample2ting were reported for YBa2 Fex Cu3−x O6+y [6, 3] and
0.94
1.00
YSr2 Fex Cu3−x O6+y [7]. According to their reports, thepresent
spectra of YSr2 FeCu2 O6+y could be assigned as
0.98
follows. The doublet with highest isomer shift in Fig.
0.96
2(a) is due to the Fe ion located at Cu(2) site and other
0.94
doublets are assigned to the Fe ion located at Cu(1) site.
0.92
The doublet with larger quadrupole splitting of Cu(1)site is assigned to the Fe ion with four - fold oxygen co0.90 c) sample 3
ordination and the other doublet comes from the Fe ion
1.00
with the ﬁve-fold oxygen coordination. The site notation
0.98(i)n in Table 1 denotes the subspectrum assigned to Fe
ion in a Cu(i) site in n-fold oxygen coordination. Other
0.96
1 (4)
1 (5) spectra of Figs. 2(b) and (c) can be assigned by same
2 (5) way without the doublet 1(4). While the spectra of high0.94
pressure O2 annealed sample (sample 2-3, Figs.2(b),(c))
is ﬁtted with two quadrupole doublets, the spectrum
-3
-2
-1
0
1
2
3
Velocity ( mm/s )of reoxidization annealed sample ( sample 1,Fig.2 (a)) consists of three quadrupole doublets. The absence ofFig. 2. Room temperature 57 Fe
the doublet assigned to 1(4) site indicates disappearenceMössbauer
spectrumsof Fe ions which occupy 1(4) site and the high pressureofYSr2 FeCu2 O6+yO2 annealing is eﬀective in spite of such low annealing
compounds at various
temperature. From the result of our analysis, the area
annealing conditions. a)ratio of the quadrupole doublets shows drastic annealReoxidization
annealedsample,b) Superconducting. In the case of reoxidized samples, the distributions
ing sample (reoxidizedof Fe ion at Cu(1) sites are 90 % and 92 % for reoxiand 190 atm high pressure
dized (sample 1) and high pressure O2 annealied sample
O2 annealed sample, c)(sample 2), respectively and the latter sample shows su190 atm high pressure O2
perconductivity. Without reoxidization annealing, 38%
annealed sample (without
Fe ion distributes to Cu(2) site. (sample 3) Pissas etreoxidization annealing).
al. studied O2 annealed sample and they also reported
that the near 50% Fe distribution to the Cu(2) site. [7] This fact suggests that the reoxidization
annealing promotes a preferred site occupation of Fe ion at Cu(1) site. It is diﬃcult to analysis
the spectrum of as synthesized specimen because the line width of the spectrum is too broad.
This may be caused by the disorder of a oxygen surrounding Fe ion at Cu(1) site and this isconsistent with the high temperature factor of the oxygen surrounding Cu(1) site observed at aneutron powder diﬀraction. [4, 8] Increasing annealing pressure of O2 , Tc and Meissner volume
fraction increased linearly and it indicates that the high pressure O2 annealing is also intrinsicallynecessary for superconductivity of YSr2 FeCu2 O6+y .
Using 57 Fe Mössbauer spectroscopy we successfully determined the Fe distribution of the- 76 -

SampleRO(Sample 1)
RO+O2 -HP (190atm)(Sample 2)O2 -HP (190atm)(Sample 3)

Site
1(5)
2(5)
1(4)
1(5)
2(5)
1(5)
2(5)

IS (mm/s)-0.0170.508
0.161-0.0300.289-0.0480.267∆Eq (mm/s)
0.822
0.507
1.910
0.726
0.515
0.726
0.535

FWHM (mm/s)
0.230
0.233
0.129
0.205
0.113
0.215
0.169

Area (%)
67
10
23
92
8
62
38

Table 1. Mössbauer parameters of YSr2 FeCu2 O6+y at room temperatures. (RO : reoxidized, O2 HP : high pressure O2 annealed) The site notation (i)n denotes the subspectrum assigned
to Fe in a Cu(i) site in n-fold oxygen coordination.

Fe ion. According to the analysis, it is revealed that the reoxidization annealing suppresses the
distribution of Fe ion to Cu(2) site and a high pressure O2 annealing provides an adequate oxygento the sample. The mechanism of superconductivity of YSr2 FeCu2 O6+y system is revealed using
57 Fe Mössbauer spectroscopy.

References[1] J. W. Lynn, B. Keimer, C. Ulrich, C. Bernhard, and J. L. Tallon, Phys. Rev. B 61 (2000)
R14964.
[2] C. Bernhard, J. L. Tallon, Ch. Niedermayer, Th. Blasius, A. Golnik, E. Brücher, R. K. Kremer,
D. R. Noakes, C. E. Stronach, and E. J. Ansaldo, Phys. Rev. B 59 (1999) 14099.
[3] M. G. Smith, J. B. Goodenough, R. D. Taylor, J. J. Neumeier, and J. O. Willis, Physica C
222 (1994) 157.
[4] P. R. Slater, and C. Greaves, Physica C 180 (1991) 299.
[5] T. Den, and T. Kobayashi, Physica C 196 (1992) 141.
[6] M. G. Smith, R. D. Taylor, and H. Oesterreicher , Phys. Rev. B 42 (1990) 4202.
[7] M. Pissas, G. Kallias, A. Simopolos, D. Niarchos, and A. Kostikas, Phys. Rev. B 46 (1992)
14119.
[8] T. Mochiku, Y. Mihara, Y. Hata, S. Kamisawa, M. Furuyama, J. Suzuki, K. Kadowaki, N.
Metoki, H. Fujii and K. Hirata, J. Phys. Soc. Jpn. 71 (2002) 790.
[9] I. S. Lyubutin, V. G. Terziev, S. V. Luchko, A. Ya. Shapiro, A. M. Balagurov, and G. A.
Bonch Osmolovsky, Physica C 199 (1992) 296.

- 77 -

3.11

The science of 3d transition-metal oxide system

M. Onoda, R. Arai, J. Hasegawa, A. Oyadomari, D. Kasuga, K. Kanbe, K. Sekine, T. Ikeda,
T. Ohki, T. Harigae, S. Miyasaka and T. Mutoh
The structural and electronic properties of 3d transition-metal oxides and bronzes have been
explored by means of x-ray four-circle diﬀraction and through measurements of magnetic resonance (NMR and EPR), magnetization, and electronic transport, in order to extract characteristic properties in the correlated electron system, electron-phonon-coupling system, quantum
spin-ﬂuctuation system, and novel materials.
At the Tandem Accelerator Center, Varian continuous-wave and Bruker pulse NMR spectrometers have been used. They have been working by a careful maintanance, but it is necessary
to renovate them in order to obtain more detailed results. In the last two years, the pulse spectrometer has been partly improved.
In 2001-2002, the following investigations have been performed and a part of them have been
published elsewhere [1–7]:• Correlated-electron and electron-phonon-coupling systems– Correlation eﬀect in SrVO3−δ/2 and Sr1−x Nax VO3– Metal-insulator transition in V6 O13– Metal-insulator transition in Cux V4 O11– Mixed valence state in Cu7 V6 O19• Quantum spin-ﬂuctuation system– Spin-gap state in the δ-MxV2 O5 (M = Ag, Tl, Na, K and Sr)– Geometrical frustration in Cdx Zn1−x V2 O4– Superexchange interaction in MVn O2n+1 (M = divalent ion; n = 1, 3 and 5); CdVO3 ,Cd1−x CaxV3 O7 , SrV5 O11 , etc.
• Lithium secondary battery system– Li inserition eﬀect in M1+xV3 O8 (M = Li, Na and Ag)– High capacity in Ag2 V4−x Mox O11
In this report, recent progress for the geometrically frustrated system is described brieﬂy [7].

Geometrically frustrated spinel system
The normal spinel-type polaronic insulator MV2 O4 with V3+ exhibits the frustration eﬀect [8].
Here, M is a nonmagnetic divalent ion surrounded tetrahedrally such as Mg or Zn (the so-called
A-site) and V has an octahedral coordination (B-site). As shown in Fig. 1, the network of the
V ions is expressed by the linkage of a regular tetrahedron block that has the V ion at each
apex as in the case of the pyrochlore-type compounds [9, 10]. On the other hand, LiV2 O4 withapparent valence of V3.5+ is a metal and it has recently been considered as being one of heavyfermion system at low temperatures [11]. The mechanism of composition-induced metal–insulatortransition in the Lix Mg1−xV2 O4 and Lix Zn1−x V2 O4 systems has been investigated from multiple
viewpoints [12].
Recently, a tetrahedral mean ﬁeld (TMF) theory of the magnetic susceptibility for the spinel
B-sublattice or the pyrochlore lattice was proposed [13]. Here, the use of the exact solution of thesusceptibility for a set of four interacting spins with Jtet in the corners of an isolated tetrahedron,- 78 -

Fig. 1: The crystal structure of ZnV2 O4 with the oxygen u parameter 0.3855 determined on thebasis of the x-ray four-circle diﬀraction [9], where the small, middle and large spheres represent
Zn, V and O atoms, respectively, and the short thin lines indicate the V–V edges of V4 tetrahedra.
in other words, the spin-singlet tetramer is essential, and thus the appearance of a maximum
in the susceptibility against temperature has been predicted. The ground-state properties for
S = 1 were also investigated by breaking up each spin into a pair of 12 -spins [14]. It has been
postulated that the twofold degeneracy of the spin singlets of the S = 12 tetrahedron is lifted by the
Jahn-Teller eﬀect, which leads to the cubic–tetragonal transition with magnetoelastic interaction.
In a preceding report [15], the structural and magnetic properties of CdV2 O4 , which is isomorphous to MgV2 O4 and ZnV2 O4 , have been described. On the basis of this result, let us see how
the V4 -tetramer model [13] explains the susceptibility data above the cubic–tetragonal transition
temperature Tc1 , although they do not exhibit the maximum phenomena in the region where thecrystal system is cubic. The susceptibility of the tetramer χtet for the present system is written

Table 1: The cubic–tetragonal transition temperature Tc1 , the antiferromagnetic-like transition
temperature Tc2 (K), and the HTSE and TMF parameters for the magnetic susceptibilities of
MV2 O4 , where M = Cd, Mg and Zn; the Curie constant C (emu K (mol V)−1 ), the constantsusceptibility χ0 (10−4 emu (mol V)−1 ) and the exchange coupling J (K) determined by the
HTSE analysis [15]; the exchange coupling inside the tetrahedron Jtet (K) based on eq. (1).
M
Cd
Mg
Zn

Tc1
97
64.5
52

Tc2
35
45
44

C
0.98(2)0.93(6)0.96(6)- 79 -

χ0
1.8(2)
1.2(3)
1.1(3)

J
44(1)
92(7)
92(7)

Jtet
82.9(1)
175.8(1)174.6(1)–1χ (10 emu (molV) )

4
M=Cd

7

2

3.4 (b) Tc2

Tc1

3.2

6
8

Zn
Mg

1.6

3.0

Mg 1.52.8

Cd 1.4

0

40

80
120
T (K)

3

160

2

7 6
8

1

7

1

(a) MV2O4
0
0

1.7 4
Zn

–3

8

3

–3

–1

χ (10 emu (molV) )

6

200

400

600

800

1000

T (K)
Fig. 2: (a) The temperature dependences of the magnetic susceptibilities χ of MV2 O4 , where M =Cd, Mg and Zn; (b) the behaviours at low temperatures. The full, dotted and dot-dashed curvesin (a) denote results calculated in terms of HTSE of up to 8th-, 7th- and 6th-order, respectively[15]; and the dashed curves indicate ﬁts to the tetramer model, where parameters used are listed
in Table 1.
asχtet =

x + 5x3 + 7x6 + 5x10
3C
+ χ0
2T 1 + 6x + 10x3 + 7x6 + 3x10

(1)with x = exp(−Jtet /T ), Jtet being deﬁned before. Here, an interaction outside the tetrahedron is
ﬁnally assumed to be zero as will be explained later. The dashed curves in Fig. 2(a) represent ﬁts
to eq. (1) with Jtet listed in Table 1, where C and χ0 are ﬁxed to the values determined in terms of
the high-temperature series expansion (HTSE) analysis of up to 8th-order [15]. For M = Cd, theagreement between the experimental and calculated results in the cubic phase is satisfactory. In
order to clarify the origin of the susceptibility maximum that appears to be reproduced roughlywith this model, the low-temperature structure should be determined precisely. On the other
hand, for M = Mg and Zn, the data above T ≈ Jtet are explained by this model, but it is diﬃcult
to ﬁt those below Jtet . For all of the compounds, Jtet is twice J within a standard deviation,
which is equivalent to the condition for the high-temperature limit in the TMF model. It should
be noted that a ﬁnite interaction outside the tetrahedron that has been introduced in reference[13] does not improve the agreement signiﬁcantly.
In summary, the susceptibility behaviour in the cubic phase of CdV2 O4 with Tc1 = 97 K and
J = 44 K agrees well with that of the spin-singlet tetramer with Jtet = 2J. On the other hand, for
the isomorphous compounds MgV2 O4 and ZnV2 O4 with Jtet > Tc1 , it is diﬃcult to ﬁt all of thesusceptibility data in the cubic phase in the framework of the present tetramer model. Therefore,
in the vanadium spinel with S = 1, the application of this model is limited to the temperature
region above T ≈ Jtet , and the present bound state may be regarded as pseudotetramers. In
other words, this restriction may justify the use of apparently isolated tetramer model for the
regular spinel B-sublattice. In order to understand the magnetic properties for the cubic phaseat temperatures below Jtet , further theoretical investigations are necessary.

- 80 -

References[1] M. Onoda and K. Kanbe: J. Phys.: Condens. Matter 13 (2001) 6675.
[2] M. Onoda and R. Arai: J. Phys.: Condens. Matter 13 (2001) 10399.
[3] A. Fujimori, M. Onoda et al: J. Elec. Spec. Relat. Phenom. 117 (2001) 277.
[4] K. Okazaki, A. Fujimori and M. Onoda: J. Phys. Soc. Jpn. 71 (2002) 822.
[5] N. Nishiguchi, M. Onoda and K. Kubo: J. Phys.: Condens. Matter in press.
[6] M. Onoda and J. Hasegawa: J. Phys.: Condens. Matter in press.
[7] N. Nishiguchi and M. Onoda: submitted to J. Phys.: Condens. Matter[8] H. Mamiya and M. Onoda: Solid State Commun. 95 (1995) 217.
[9] M. Onoda: unpublished results (1996).
[10] H. Sakai, K. Yoshimura, H. Ohno, H. Kato, S. Kambe, R. E. Walstedt, T. D. Matsuda, Y.
Haga and Y. Ōnuki: J. Phys.: Condens. Matter 13 (2001) L785.
[11] S. Kondo S, D. C. Johnston, C. A. Swenson, F. Borsa, A. V. Mahajan, L. L. Miller, T. Gu,
A. I. Goldman, M. B. Maple, D. A. Gajewski, E. J. Freeman, N. R. Dilley, R. P. Dickey, J.
Merrin, K. Kojima, G. M. Luke, Y. J. Uemura, O. Chmaissem and J. D. Jorgensen: Phys.
Rev. Lett. 78 (1997) 3729.
[12] M. Onoda, H. Imai, Y. Amako and H. Nagasawa: Phys. Rev. B 56 (1997) 3760.
[13] A. J. Garcı́a-Adeva and D. L. Huber: Phys. Rev. Lett. 85 (2000) 4598.
[14] Y. Yamashita and K. Ueda: Phys. Rev. Lett. 85 (2000) 4960.
[15] M. Onoda, N. Nishiguchi, R. Arai, I. Amemiya, K. Kogure, J. Hasegawa, A. Oyadomari, D.
Kasuga, K. Kanbe, H. Imai, K. Sekine, A. Tokunaga and T. Banno: UTTAC Annual Report(2001) p. 80.

- 81 -

4.1

Suppression of nuclear-cascade gamma-ray background analysis

K. Furuno, A. Tanaka, H. Ohsima, M. Ishizuka, S. Yokose, K. Sasa, and T. Komatsubara
Resonant nuclear reaction analysis(RNRA) using the 1 H(15 N,αγ)12 C or 1 H(19 F,αγ)16 O reaction is widely usedin hydrogen analysis. Most of investigations reported so far have been performed by means of low energy accelerators, and consequently limited to measurements of hydrogen concentration near the surface of samples.
One of recent important subjects in earth science is the measurement of hydrogen concentration in fluid inclusions confined in minerals or rocks. Since the size of fluid inclusions is in the range from 30 to 100 microns, theenergy of 19 F beam in the 1 H(19 F,αγ)16 O reaction must be increased up to about 70 MeV to cover the whole range
of a fluid inclusion as large as 30 microns. A serious problem at such high beam energies is that the yield of continuum γ rays due to compound nuclear reactions with carbon, oxygen, and silicon in silicate samples becomes hugebackground for the 6.13 MeV γ ray originated from the reaction with hydrogen.
The continuum γ rays are comprised of statistical and cascade γ rays emitted from fusion-evaporation residues,
so that several number of γ rays are emitted per one nuclear reaction event. The number of γ rays is defined as γ
multiplicity M in nuclear physics. On the contrary, the γ multiplicity of M = 1 is dominant in the 1 H(19 F,αγ)16 O
reaction for the 19 F energies up to 70 MeV, because excited states in 16 O higher than 7.15 MeV are above the12

C+α threshold and the probability of γ-ray emission from excited states higher than the threshold becomes very

low by virtue of competeing α-particle emissions. This differnce of the γ multiplicity in the compound nuclear
reactions other than hydrogen from the 1 H(19 F,αγ)16 O reaction can be utilized to partly suppress the continuum γ
ray background by using a multiple γ-ray detector system operated in the anti-coincidence mode.
A test experiment was performed with the arrangement shown in Fig.
1. A 19 F beam delivered by the 12 UD Pelletron tandem accelerator was
focused onto a target on the end plate of the Faraday cup. The target
was a silica glass of 8 mm in diameter and 0.5 mm in thickness. The
surface of the glass was artificially hydrated at a temperature of 450◦C
and at pressure as high as 60 MPa. To avoid charging up during beamirradiation, the surface of the target was coated with 100 A thick carbon.
Four tightly bounded NaI detectors were placed behined the silica glass

Fig. 1. Target and detectors

target.
This arrangement of the detectors was employed to introduce light for a microscope for observation of samples
in the new vaccum chamber under construction. The distance between the target and front ends of NaI detectors
was 1 cm. Fig. 2 shows a block diagram of the electronics. Timing signals from four detectors were fed intoa linear FAN-IN/FAN-OUT module. The threshold of CFD connected to FAN-IN/FAN-OUT was adjusted at alevel slightly higher than one logic pulse height. The output pulses from CFD were coincidence signal when atleast two NaI detectors fired, and were converted to anti-coincidence signals by taking OUT in DISC-A connected
to CFD. Energy signals from each NaI detector were gated by the anti-coincidence pulses. Gamma rays emitted
simultaneously from the compound nuclear reactions hit more than two NaI detectors, and thus they were rejectedwith some probability which depends on solid angles and detction efficiencies of the NaI detectors.
Typical γ ray spectra obtained in this test experiment are displayed in Fig. 3, and Fig.4. The spectrum in Fig.
3 was observed at the 19 F beam energy of 20 MeV. The energy calibration was carried out using standard sources- 82 -

Fig. 2. Block diagram of the γ ray detection system. SA’s are spectroscopy amplifiers(EG&G ORTEC
model 572). TFA’s are timing filter amplifiers(EG&G ORTEC model 474). DISC-1, DISC-2, DISC-3,
DISC-4, DISC-A and DISC-B are fast discriminators(LeCroy model 821). The linear FAN-IN/FAN-OUT
is the model 428F supplied by LeCroy. CFD is a constant fraction discriminator(EG&G ORTEC model
473A). A 4 channel coincidence module(LeCroy model 622) was used as AND’s.

of 137 Cs(0.661 MeV), 22 Na(1.27 MeV), 60 Co(1.33 MeV) and Am+Be(4.44 MeV). At 20 MeV, the center-of-massenergy is much lower than the Coulomb barrier heights between nuclei other than hydrogen and incident 19 F nucleus,
and the cross section of compound nuclear reactions are very small. The background under the 6.13 and 6.92 MeV
γ rays is almost negligible. At a bombarding energy of 33 MeV, however, the background becomes huge as shownin Fig. 4. The upper spectrum is a singles spectrum, while the lower spectrum is observed in the anti-coincidence
mode. The resolving time for the 2-fold coincidence was 50 ns. The ratio of the anti-coincidence yield to singles
yield was 0.64 for an integrated number of counts between the channels 470 and 570.
This experimental ratio of the yields can be compared with the following theoretical prediction. Let the numberof γ-ray detectors and the γ multiplicity be N and M , respectively. We assume that detection efficiencies Ωε/4π
are identical for all detectors. The probability of p-fold coincidence is given by[1]
M
PN,p
=N Cp

p


(−1)p−l p Cl 1 − (N − l)

l=0

Ωε
4π

M

,

(1)

where N Cp stands for the number of combinations for taking p out of N .

The probability of singles events is simply given by M (Ωε/4π).
The probability that more than two γ rays hit one of the detectors simultaneously and other γ rays do not hit anyother detectors can be written as


P =

M

q=2


M Cq

Ωε
4π

q
1 − {N − (q − 1)}- 83 -

Ωε
4π

M −q

.

(2)

Counts per Channel

Counts per Channel

60

40

20

600
Singles

400
200With anticoincidence
0

0
400

500
600
700
Channel Number

400

800

500

600

700

800

Channel Number

Fig. 3. A gamma ray spectrum observed at 20 MeV

Fig. 4. Gamma ray spectra observed at 33 MeV

We estimated the γ multiplicity M to be 5 from the angular momentum carried into thedScompound nucleus at the 19 F beam energy of 33 MeV and reaction Q values. The de-( a )tection efficiency Ωε/4π was estimated in the following manner. In the experimentalSsarrangement shown in Fig. 1, the source is not on the axis of the scintillator. Relative( b )efficiencies were measured for three source positions to the detectors shown in Fig. 5.

dx

The first arrangement in Fig. 5(a), the source was placed on the axis and the distance( c )d was changed. The second arrangement in Fig. 5(b) the detector was displaced byS

the distance s with fixed d. The third arrangement in Fig. 5(c), the source was moved

Fig. 5. Source positions withrespect to the detector

in the radial direction. The experimetal results are plotted in Fig. 6 as functions of
distances d, s and x. The efficiency is normalized to unity at the distances ofd = 0.4 and s = 0 cm. The absolute efficiency for this source position was calculated using the following wellknown formula;
1
Ωε
=
4π
2
+

1
2

 θ1
0

 θ0
θ1



L
1 − exp −µl (Eγ )sin θ dθ
cos θ



R
d
1 − exp −µl (Eγ )−sin θ dθ,
sin θ
cos θ

(3)

where R and L are the radius and length of the scintillator. The angles θ0 and θ1 are given byθ0 = tan−1

R
D

and

θ1 = tan−1

R
.
D+L

(4)

Substituting numerical values of d = 1 cm, L = 7.6 cm, R = 3.8 cm, we obtained the efficiency to be(Ωε/4π)axis = 0.134. We took the total linear absorption coefficient to be µl (Eγ ) = 0.13 [cm−1 ] at a γ-ray energyof 6.13 MeV from the table reported by Strom and Israel[2]. The result shown in Fig. 6 indicates that the effciecy
drops to 0.35 at s = 5.4cm. Multiplying this factor by the efficiency on axis(0.134), we obtained the detection
M
and Psingles (M (Ωε/4π) + P  ) were estimated toefficiency of 0.047. With this efficiency, the probabilities of PN,pbe 0.0992 and 0.251, respctively. Thus, the ratio of anticoincidence counts to the singles counts is calculated to be
0.6. This result is in reasonable agreement with the experimental ratio of 0.64. If we use BGO detectors instead of
NaI detectors, the ratio would be improved to 0.5.

- 84 -

Realtive efficiency

1
0.8
0.6
0.4
0.2
0

0

1

2

3

4

5

6

7

8

Distance d, s, or x [cm]Fig. 6. Detection efficiency as a function of the displacement of the source position. Closed circles are
relative efficiencies in the arrangement (b) in Fig. 5 with the distance d = 1cm. Closed diamonds indicatesefficiencies obtained for the arrangement (a) in Fig. 5. Crosses are the results for the arrangement (c) in
Fig.5. The solid curve shows an efficiency for the arrangement (a) calculated with eq. (3).

References[1] S.Y. Van der Werf, Nucl. Instr. Meth. B84 (1994) 380-392.
[2] E. Strom and H.I. Israel, Nucl. Data Tables, A7 (1970) 565-681.

- 85 -

4.2

Hydrogen analysis by proton ERCS technique

T. Komatsubara, K. Sasa, K. Shima, H. Ohshima, H. Kimura, Y. Tajima, T. Takahashi, S. Ishii,
Y. Yamato, T. Kurosawa∗ , K. Furuno* Institute of Geoscience, Univ. of Tsukuba, Tsukuba, Ibaraki 305-8577, JapanFor applications to geo-scientiﬁc researches, hydrogen analysis has been emphasized to beimportant for the evolution and dynamics of the earth[1, 2]. To develop a hydrogen analysis
method for mineral samples, a test experiment of elastic recoil coincidence spectrometry (ERCS)[3, 4] was carried out.
A stacked target which consists of four aluminum foils of 50 µm in thickness and ﬁve mylar ﬁlms was irradiated by proton beam at 17 MeV. Thickness of the mylar ﬁlm (polyethylene
terephthalate, (C10 H8 O4 )n ) was measured to be 0.79mg/cm 2 which corresponds to 5.7 µm thick.
The hydrogen density in the mylar ﬁlm is calculated to be 33 µg/cm2 .
For detection of proton-proton coincidence events produced from elastic scattering by protonin the mylar ﬁlms, two Si detectors of 2mm in thickness were placed at ±45◦ with respect to thebeam axis. The distances from the stacked target to the detectors were both 125 mm. Deﬁning
slits of 9 mm in diameter were located in front of the detectors. Solid angles of the detectors wereboth 4.1 msr. Coincidence time window was adjusted to be 40 nsec by using TAC module.
When the stacked sample was irradiated by high energy proton beam a measured spectrum
was very complex due to many nuclear reactions. Fig. 1(a) shows a singles spectrum which
includes many elastic and inelastic particles from aluminum, oxygen, carbon and hydrogen in
the stacked targets. However, the coincidence measurement can select proton-proton elastic
scatterings. Projected spectrum of the coincidence events is shown in Fig. 1(b). A small bumpin Fig 1(a) is also the coincidence spectrum compared with the singles. Singles and coincidence
counting rates were 2400 and 35 cps, respectively, with 0.4 nA of proton beam intensity. The
rate of chance coincidence events can be calculated to be 0.2 cps.
As a result of the coincidence measurement, 2-dimensional spectrum is shown in Fig. 2, in
which both axis show measured energies by the two detectors. Five lines correspond to scattering
protons from each layer of ﬁve mylar foils. When a projectile proton is scattered by a protonin the target, the kinetic energy is shared with the recoil proton. Since stopping power for the
scattered and recoil protons are twice larger than for the projectile, the sum of energy losses
depends on the depth from the ejecting surface. Fig. 3(a) shows a diagonal projection of the
2-dimensional matrix. Energies calculated using stopping powers in reference [5] are compared inFig. 3(b). Peak positions of sum energies of two protons are well reproduced by the calculation.
Measured intensities for the ﬁve peaks are shown in Fig. 4 as a function of the depth from theejecting surface. Exponential decay of the intensity observed in this ﬁgure could imply single
and/or multiple scatterings of scattered and recoil protons.
From the test experiment, it has clearly turned out that proton density and its depth proﬁlecan be measured by the proton-proton ERCS with high energy proton beam.

References[1] M. Kurosawa, S. Sueno, K. Shima, H. Oshima, S. Ishii, H. Kamiya, S. Kimoto, H. Ohyi, K.
Hayashi, Nucl. Inst. and Meth. B 142 (1998) 599[2] S.H. Sie, G.F. Suter, A. Chekhmir, T.H. Green, Nucl. Inst. and Meth. B 104 (1995) 261[3] B.L. Cohen, C.L. Fink, J.H. Degnan, J. Appl. Phys. 43 (1972) 19- 86 -

[4] H.C. Hofsäss, N.R. Parikh, M.L. Swanson, W.K. Chu, Nucl. Inst. and Meth. B 45 (1990)
151[5] J.F. Ziegler, J.P Biersack, U. Littmark, “The Stopping and Range of Ions in Solids”, Pergamon Press, New York (1985); Program SRIM, J.F. Ziegler, IBM-Research
30000

(a)

25000

20000

Singles

15000

Counts/Channel

Coincidence
10000

5000

0

(b)
1500

Proton−proton coincidence
1000

500

0
0

100

200

300

400

500

ChannelFig. 1 (a) A singles and a projection of coincidence events of charged particle energy spectra
measured by a Si detector. (b) The projection of the coincidence events with expanded scale.

300

Channel

200

100

0
0

100

200

300

ChannelFig. 2 A 2-dimensional spectrum for a stacked target of 4 aluminum and 5 mylar foils.

- 87 -

Mylar : 0.79 mg/cm2 (5.7 µ m)

1000

Al : 13.45 mg/cm2 (50 µ m)

14.2 MeV

12.6 MeV

9.2 MeV

2000

11.0 MeV

Beam: 17 MeV proton
Target: Stack of 5 Mylar and 4 Al foils
Detector angle: 45 degree

3000

Counts/Channels

Coincidence proton spectrum

15.6 MeV

(a)

4000

0

(b)

150

Calculation
with stopping power

100

50

0
0

100

200

300

400

500

Channels

Fig. 3 (a) Diagonal projection of the 2-dimensional spectrum shown in Fig. 2. (b) A result of
calculation by use of stopping power of incident and recoil protons. Sum of energies of scatteredand recoil protons are shown in a unit of MeV.
50000

Peak intensity [counts]

30000

10000

5000

3000

1000
0

50

100

150

200

250

Depth of alminum [ µ m]

Fig. 4 Measured intensity corresponding to 5 mylar foils as a function of distance from theejecting surface.

- 88 -

4.3

Status of Tsukuba AMS system

Y. Nagashima, R. Seki, T. Takahashi, T. Matsuhiro, K. Sasa, and H. Kume1
In this year, AMS group has made great efforts towards achieving higher precision andreproducibility on the 36Cl measurements. As one of the instrumental improvements, the high-voltage
power supply for the electrostatic deflector located just after the ion-source einzel lens has been replacedby new one because of the lack of its stability.
In order to investigate the influence of nuclear power plants on an environment, 36Cl in soils was
extensively studied. The 36Cl is very suitable isotope to see the long-term environmental changes due tosuch human activities as man made nuclear activities because of both its very long halflife of about 0.3
million years and very low natural abundance less than 10-14 in the ratio of 36Cl to 35Cl. The soils were
sampled in the area of Tokai and in the Tsukuba area. Fig. 1 shows a horizontal distribution of 36Cl in
Tokai village. The mark JCO shows the location of a JCO nuclear fuel company in which a critical nuclear
accident occurred on September 30, 1999. The results indicate that the JCO accident fortunately caused
little radioactive contamination in the environment in the vicinity of JCO. In contrast with JCO area, it
was clearly demonstrated that the 36Cl to 35Cl of Tokai samples are 10 - 100 times as large as that ofTsukuba samples, and that the ratios in the coastal area were much higher than those in the inland area.
These experimental evidences imply environmental pollution brought by the human activities related to anuclear power. Many facilities for nuclear research and plant are constructed and are operated in the
coastal area of Tokai village, but not so many in the inland area. In order to understand the origin of thishigh ratio of 36Cl/Cl, we continue to measure the 36Cl contents in many samples taken from a site of othernuclear plants.
The DS86 dosimetry system has been used for survivors of the Hiroshima and Nagasaki atomic
bombs since 1987. In the thermal neutron evaluation, a systematic discrepancy has been observed between
152

Eu data measured by Shizuma and Nakanishi and the calculation based on the DS86. As one of thecontribution to understand the source of the discrepancy, the measurements of 36Cl in granite samples has
been commenced with the Tsukuba AMS system. Seventeen bombed granite samples were chosen andanalyzed. These granites are sampled at the location of 146 - 1400m distance from hypo-center. In
addition to the bombed granites, 7 un-bombed granite samples were prepared for background estimation
because 36Cl was also created in the granite itself as an in-situ formation. Each granite sample wasseparated into 4 blocks and each block was sent to 4 laboratories. One laboratory at Kanazawa takes the
responsibility for 152Eu measurement. Remaining 3 laboratories, Tsukuba, Munchen and LLNL, bear the
responsibility for 36Cl measurement. The ratios of 36Cl to 35Cl of 14 samples have been measured. It seems
that there is little discrepancy between the DS86 calculation and the 36Cl measurement. The investigationis still going on. It is expected that the origin of the discrepancy will be made clear after finishing of theinter-comparison measurements by 4 laboratories.

1

National Institute for Environmental Studies- 89 -

Fig.136

Cl/35Cl ratio map in Tokai village- 90 -

5.

LIST OF PUBLICATIONSNUCLEAR PHYSICS----EXPERIMENT
C.B. Moon, S.J. Chae, J.H. Ha, T. Komatsubara, Y. Sasaki, T. Jumatsu, K. Yamada, K. Satou, K. Furuno
Level structure of 120Cs
Nucl. Phys. A696 (2001) 45-63.
T. Shizuma, K. Matsuura, Y. Toh, Y. Hayakawa, M. Oshima, Y. Hatsukawa, M. Matsuda, K. Furuno, Y. Sasaki, T.
Komatsubara, Y.R. Shimizu
Multi-quasiparticle states and K-forbidden transitions in 183Os,
Nucl. Phys. A696 (2001) 337-370.
C.B. Moon, T. Komatsubara, K. Furuno
Rotational bands built on the proton h(11/2) orbital in 121Cs
Journal of the Korean Physical Society 38 (2001) 83-87.
Y.H. Zhang, T. Hayakawa, M. Oshima, Y. Toh, J. Katakura, Y. Hatsukawa, M. Matsuda, N. Shinohara, T. Ishii, H.
Kusakari, M. Sugawara, T. Komatsubara
Doubly decoupled structure in odd-odd 178-186Ir nuclei,
Chinese Physics Letters 18 (2001) 27-29.
Y.H. Zhang, T. Hayakawa, M. Oshima, Y. Toh, J. Katakura, Y. Hatsukawa, M. Matsuda, N. Shinohara, T. Ishii, H.
Kusakari, M. Sugawara, T. Komatsubara, K. Furuno
Search for signature inversion in the πi13/2 x νi13/2 band in odd-odd 178Ir
Chinese Physics Letters 18 (2001) 1323-1326.
X.H. Zhou, Y. Zheng, Y.H. Zhang, Z. Liu, Q.Y. Pan, Z.G. Gan, T. Hayakawa, M. Oshima, Y. Toh, T. Shizuma, J.
Katakura, Y. Hatsukawa, M. Matsuda, H. Kusakari, M. Sugawara, K. Furuno, T. Komatsubara,
In-Beam Study of 145Tb,
Eur.Phys.J. A 12 (2001) 253.
Y.H. Zhang, T. Hayakawa, M. Oshima, J. Katakura, Y. Hatsukawa, M. Matsuda, H. Kusakari, M. Sugawara, T.
Komatsubara, K. Furuno
Configuration-dependent band structures in odd-odd 180Ir
Phys.Rev. C65 (2002) 014302.
K. Nishio, H. Ikezoe, S. Mitsuoka, K. Satou, S.C. Jeong
Effects of nuclear deformation on fusion probability in the reactions of 82Se + natCe and 76Ge + 150Nd near the
Coulomb barrier.
Phys.Rev. C63 (2001) 044610.
T.Katabuchi, K.Kudo, K.Masuno, T.Iizuka, Y.Aoki and Y.Tagishi,
Polarization transfer for the 2H(d,p)3H reaction at θ=0Gat a very low energy
SPIN 2000, 14th Int. Spin Physics Symp. Osaka Japan 2000, AIP conf. Proceedings 570, p.694-698, 2001

- 91 -

T.Katabuchi, K.Kudo, K.Masuno, T.Iizuka, Y.Aoki and Y.Tagishi,
Polarization transfer coefficient Ky’y in the 2H(d,p)3H reaction at θ=0Gat very low energies
Phys. Rev. C 64 (2001) 047601-1-047601-3.
N.Kawachi, T.Katabuchi, M.Yamaguchi and Y.Tagishi,
Real-time measurement of implanted deuterons by using the nuclear reaction 2H(d,p)3H
15th Intern. Conf. on Ion Beam Analysis, Cairns, Australia (2001), Nucl. Instrum. Methods B190 (2002) 887.
NUCLEAR PHYSICS----THEORYy

T. Une ,Study of tilted rotation based on the method of variation after projection,
Prog. Theor. Phys. 106 (2001) 941.
HIGH ENERGY NUCLEAR PHYSICS
T. Abbott, Y. Miake, et.al.,
Systematics of midrapidity transverse energy distributions in limited apertures from p + Be to Au + Au collisions
at REL at relativistic energies.
Phys.Rev.C63 (2001) 064602, Erratum-ibid.C64 (2001) 029901.
K. Adcox, S. Esumi, A. Kiyomichi, Y. Miake,M. OnoM. Suzuki, H. Tsuruoka,et.al.,Measurement of midrapidity transverse energy distribution from S(NN)**(1/2) = 130-GeV Au+Au Collision at
RHIC.
Phys.Rev.Lett.87 (2001) 052301.
K. Adcox, S. Esumi, A. Kiyomichi, Y. Miake,M. OnoM. Suzuki, H. Tsuruoka,et.al.,
Suppression of hadrons with large transverse momentum in central Au+Au collisions at S(NN)**(1/2)= 130-GeV.
Phys.Rev.Lett.88 (2002) 022301.
M.M. Aggarwal, Y. Miake, et.al.,
Direct photons in WA98.
Nucl.Phys.A698 (2002) 135-142.
L. Rosselet, Y. Miake, et.al.,One-, two- and three-particle distributions from central Pb+Pb collisions at 158-A-GeV/c.
Nucl.Phys.A698 (2002) 647-650.
W.A. Zajc, S. Esumi, A. Kiyomichi, Y. Miake,M. OnoM. Suzuki, H. Tsuruoka,et.al.,
Overview of PHENIX results from the first RHIC run.
Nucl.Phys.A698 (2002) 39-53.
M.M. Aggarwal, Y. Miake, et.al.,Transverse mass distributions of neutral pions from 208Pb induced reactions at 158-A-GeV.
Eur.Phys.J.C23 (2002) 225-236.

- 92 -

Y. Miake,
High PT Project of PHENIX,
Yonsei-Tsukuba Workshop, Yonsei, Korea, Aug.20-22, 2001
D. Adamova, S. Esumi et al.
New results from CERES.
Nucl.Phys.A698 (2002) 253-260.
I.G. Bearden, S. Esumi et al.
Two Kaon correlations in central Pb + Pb collisions at 158 A GeV/c.
Phys.Rev.Lett.87 (2001) 112301.
Mikhail L. Kopytine, S. Esumi et al.
Event texture search for critical fluctuations in Pb + Pb collisions.
Nucl.Phys.A698 (2002) 651-654.
I.G. Bearden , S. Esumi et al.
One-dimensional and two-dimensional analysis of 3 PI correlations measured in Pb + Pb interactions.
Phys.Lett.B517 (2001) 25-31.
ATOMIC AND SOLID STATE PHYSICS, AND CLUSTER SCIENCE
H.Kudo, T.Kumaki, K.Haruyama, Y.Tsukamoto, S.Seki, H.Naramoto,
Structural analysis of bent KCl and NaCl crystals with ion-induced electron spectroscopy.
Nucl. Instrum. & Methods B174 (2001) 512-518.
H.Kudo, K.Haruyama, T.Kinoshita, K.Narumi, H.Naramoto and S.Seki,
Carbon KLLAuger electron emission from HOPG bombarded by 1 MeV H+
15th Intern. Conf. on Ion Beam Analysis (Cairns, Australia, July, 2001), Nucl. Instrum. Methods B190 (2002) 160.
Ion-Induced Electron Emission from Crystalline Solids,
H. Kudo,Springer Tracts in Modern Physics, vol. 175, Springer, Berlin, Heidelberg, 2002.
M. Imanaka, T. Kurita, M. Tsukada, I. Arai, S.M. Lee and T. Nakagawa,
Effect of a biased electrode on operation of electron cyclotron resonance ion source using liquid He freesuperconduction solenoid coils,
Rev. Scientific Instruments, 73 (2002) 592-594.
I. Arai, H. Sasaki, J. Hirose, K. Teranishi and S.M. Lee,
Abundance spectra of clusters for various metals in sputtering and their formation mechanism,
Transactions of Materials Research Society of Japan, 27 (2002) 193-196.
M. Imanaka, T. Kurita, T. Nakagawa, H. Sasaki, S.G. Lee, I. Arai and S.M. Lee,
Highly-charged ion beam for study of cluster physics,
Ibid., pp181-184- 93 -

M. Imanaka, T. Kurita, M. Tsukada, T. Nakagawa, S.M. Lee,
The effect of a biased electrode of ECR ion source using liquid He free superconducting solenoid coils ,The 9th Intern. Conf. on Ion Sources, Oakland, California USA, Sep. 2001.
S.M. Lee,
Atomic cluster and nanoscience,
Invited lecture, Natural science division, Academy of Science, Democratic People's Rep. of Korea, June 20, 2001.
M. Onoda and K. Kanbe,
Crystal structure and electronic properties of the Ag2V4O11 insertion electrode,
J. Phys.: Condensed Matter, 13 (2001) 6675-6685.
M. Onoda and R. Arai,
The spin-gap state and the linear-chain state in $¥delta$-phase AgxV2O5 with a double-layered structure,
Journal of Physics: Condensed Matter, 13 (2001) 10399-10416.
A. Fujimori, M. Onoda et al,
Electronic structure of Mott-Hubbard-type transition-metal oxides,
J.Electron Spectroscopy and Related Phenomena, 117 (2001) 277-286.
K. Okazaki, A. Fujimori and M. Onoda,
Temperature-dependent electronic structure of VO2 in the insulating phase,
J. Phys. Soc. Japan, 71 (2002) 822-825.
M. Nishikawa, Kazunaga Ono, Eiji Kita, H. Yanagihara, T. Erata and A. Tasaki
Magnetic properties and structures of Fe,Co/MgF2 multilayered films.
J. Magn. Magn. Mater., 238 (2002) 91-100.
Tanimoto, H., Koda, Y., Sakai, S., Kita, E. and Mizubayashi, H.
Thermal Stability of Nanocrystalline structure FCC metals.
Proc. of the 22nd Riso Intern. Symp. on Materials Science : Science of Metastable and Nanocrystalline Alloys,
Structure, Properties and Modelling, Riso National Laboratory, Roskilde, Denmark, 3-7 Sept., 2001, ed. by A.R.
Dinesen et al., p. 401-406.
Sakai, S, Tanimoto, H, Otsuka, K., Yamada, T., Koda, Y., Kita E. and Mizubayashi, H.
Elastic behaviors of high density nanocrystalline gold prepared by gas deposition method
Scripta Mater. 45 (2001) 1313-1319.
ION BEAM APPLICATION

K. Sasa, H. Ohshima, Y. Yamato, T. Komatsubara, T. Katabuchi, K. Shima, K. Furuno, M. Kurosawa, N.
Yanagisawa.
Hydrogen analysis of mineral samples at University of Tsukuba.
15th Intern. Conf. on Ion Beam Analysis (Cairns, Australia, July, 2001), Nucl. Instrum. Methods in Physics
Research, B 190 (2002) 287-290.

- 94 -

6. THESES
Ph. D. Theses
T.Kurita
K.Ono
M. Sc. Theses
M.Ono
H.Tsuruoka
K.KanbeDevelopement of ECR ion source using liquid helium freesuperconducting solenoid coils.
Magneto-optical propeties and tunneling conduction of Fe,Co/MgF2
Fe,Co/MgF2 granular multilayers.
Azimuthal anisotropy of particle emission in Au +Au collisions at RHIC-PHENIX.
Development of collision detector for p+p collision measurements at RHIC-PHENIX.
Crystal structure and transport mechanism of Ag2V4O11, and the application to the secondary
ion battery.

T.Iiduka
S.Yokose
A.Negishi
A.Oyadomari
D.Kasuga

The 6Li(d,α)4He reaction at an incident energy of 90 keV.
Lifetime measurement of the ground-state rotational band in 165Ho.
Formation Process of Transition Metal Silicide
Basic properties of the Li ion battery system Ag1+xV3O8
Electron correlation in the perovskite-type SrVO3 system

K.Takeda
T.NakanishiElectron loss from channeled ions
Fabrication of microstructures in rutile TiO2 single crystals by swift heavy-ion irradiation- 95 -

7. SEMINARS
Date
2001
June 6
June 13
June 20
July

4July 11
July 18
July 25
Sept. 12
Sept. 19
Sept. 26
Oct.

3Oct. 10
Oct. 24
Oct. 31
Nov. 7
Nov. 14
Nov. 28
Nov. 29
Dec.

5Dec. 12
Dec. 19
Dec. 20
Dec. 26

Speaker and Title
T.R.Saitoh (Max-Planck-Inst. Heidelberg) ; Physics with gamma-rays; nuclear,
nucleon and astrophysics.
I.Arai (Univ. of Tsukuba); Growth of nanostructures on surface.
K.Awazu ; Fabrication of microstructures in rutile TiO2 single crystal using 
structural change induced by swift heavy-ion bombardment.
M.Kurosawa ; Quantitative trace element analysis of single fluid inclusion inquartz by PIXE.
Y.Nagashima (Univ. of Tsukuba) ; Accelerator Mass Spectrometry.
K.Kondo (TARA, Univ. of Tsukuba) ; Interaction in optical high field withultrashort high peak power.
H.Kudo (Univ. of Tsukuba); Surface phenomena induced by bombardment of
Fast ions.
K.Sasa ; Report on Ion Beam Analysis 2001.
Y.Aoki (Univ. of Tsukuna); What is the blanketting material of nuclear fusion
reactor ?
T.Hayakawa, T.Shizuma, T.Yamauchi, T.Arisawa (JAERI); Study plan of the nuclear astrophysics andnuclear isomer using photon sources.
M.Tomizawa (KEK); Accelerators of JAERI/KEK high intensity accelerator project and JAERI/KEK
RI beam facility based on ISOL.
T.Sakae (Univ. of Tsukuna);Proton cancer treatment in Univ. of Tsukuba.
T.Komatsuba (Univ. of Tsukuba); Report of the 1st Joint Meeting of the Nuclear
Physics Division of APS and JPS, Hawaii.
H.Miyatake (KEK) ; Joint RNB Project of KEK-JAERI.
T.Kanai (HIMAC) ; Physical and biological background of heavy ion
Radiotherapy.
J.Kasagi (Tohoku Univ.);Nuclear resonances in nuclei studied with GeV photons.
Y.Gono (Kyushu Univ.) ; Recent development of gamma-ray detection system.
M.Yamaguchi (Univ. of Tsukuba); Development of proton polarimeter andbreakup effects of deuterons in (d, p) reaction.
Y.Kawachi (Univ. of Tsukuba); Real time measurement of implanted deuterons
by using the 2H(d,p)3H reaction.
T.Nishitani (JAERI); Nuclear fusion and Nuclear Data ---- ITER Project.
T.Iizuka (Univ. of Tsukuba); The 6Li(d, α)4He reaction at an incident deuteronenergy of 90 keV.
S.Kubono (Tokyo Univ.); Explosion process of universe----- approach from
nuclear physics.
H.Yokomizo (JAERI); Outline and status of the high intensity proton accelerator
Project.

- 96 -

2002
Jan. 9Jan. 23

Jan. 24

Jan. 30
Feb. 13
Feb. 27
March 6
March13
March20

M.Ogawa (Tokyo Inst. Technology); Increase of stopping power of high density
plasma for fast heavy ions.
M.Ono (Univ. of Tsukuba); Measurement of azimuthal anisotropy of particle
emission in Au+Au collisions at RHIC-PHENIX.
H.Turuoka (Univ. of Tsukuba); Design and manufacturing of the trigger and start
counter for p + p collisions at RHIC-PHENIX.
A.Negishi (Univ. of Tsukuba); The formation of transition metal silicide clusters observed by FT-ICR
mass spectrometry.
S.Yokose (Univ. of Tsukuba); Lifetime measurement of the ground-state rotational band in 165Ho.
T.Ishii (JAERI); Nuclear structure of neutron access Ni region using the deep-inelastic scattering.
Y.Saito (JAERI); Acceleration of cluster ions to MeV energy region.
S.Ezumi (Univ. of Tsukuba); QGP formation in heavy-ion collisions at SPS
energies and recent news from RHIC experiments.
N.Sakamoto (Nara Women’s Univ.); Status of the tandem accelerator at NWU.
Y.Shimizu (Kyushu Univ.) ; A tunneling phenomenon in nuclear structure.
T.Miyazaki (Univ. of Tsukuba); Emission of cluster from liquid
M.Nakamura (Kyoto Univ.); Basics of the accelerator mass spectrometry
Y.Iseri (Chiba-Keizai Junior Coll.); Determination of S17 based on CDCC
analyses for 7Be(d, n)8B

8. SYMPOSIUM

Ion Beam Analysis of Materials
January 16, 2002
Tandem Accelerator Center, University of Tsukuba
Opening, K.Shima (Univ. of Tsukuba)
Reconsideration of the neutron doze in atomic bomb in Hiroshima, K.Shizunma (Hiroshima Univ.)
Ion-induced electron spectroscopy sensitive to the structure analysis, H.Kudo (Univ. of Tsukuba)
Behavior of hydrogen in carbon foils, I.Sugai (KEK)
Hydrogen analysis in rocks by ERDA using high-velocity proton beams, T.Komatsubara (Univ. of Tsukuba)
PIXE at NMCC, K.Sera (Iwate Medical Univ.)
Application of Ion beam analysis to mineral samples, M.Kurosawa (Univ. of Tsukuba)
Development and application of ion micro-beam technology at TIARA in JAERI, T.Kamiya(JAERI Takasaki)
Development of micro-beam facility for hydrogen analysis at UTTAC, K.Sasa (University of Tsukuba)
Closing remarks, K.Furuno (Univ. of Tsukuba)- 97 -

9. LIST OF PERSONNEL
Accelerator Center
K. Furuno
K.Shima
T.Komatsubara
K.SasaT.Katabuchi
S.Ishii
H.Kimura
H.Oshima
Y.Tajima
T.Takahashi
Y.Yamato
Li Tian-Xin
K.TagaDirector, Professor
Associate Professor
Assistant Professor
Assistant Professor
Research Associate
Mechanical Technician
Computer Technician
Electric Technician
Mechanical Technician
Electric Technician
Electronics Technician
Research Fellow
Administrative Stuff

Steering Committee
K.Furuno
Y.Kajiwara
R.Kanzaki
T.Komatsubara
H.KudoS.M.Lee
M.OnodaR.Seki
K.ShimaY.Tagishi
K.Yabana
K.Yasuoka

Chairperson, TandemAccelerator Center
Inst. of Geoscience
Inst. of Biological Sciences
TandemAccelerator Center,Inst. of Applied Physics
Inst. of Physics
Inst. of Physics
Inst. of Chemistry
TandemAccelerator Center
Inst. of Physics
Inst. of Physics
Inst. of Basic Medical Sciences

Scientific Guests and Fellows
C.B.Moon
Zhang Yu-Hu
K.Awazu
M.Fujimaki
T.Nakanishi
K.Nomura
Y.HataI.Daitou
Wang Li
T.Mizota
H.Ishihara

Hoseo Univ., Korea
IMP, Lanzhou
National Lab. Advanced Industrial Science and Technology
National Lab. Advanced Industrial Science and Technology
Waseda Univ.
Waseda Univ.
JAERI
Nagoya Univ.
Nagoya Univ.
Tsukuba Nano-Tech.
KEK- 98 -

Research Members
Inst. of Physics
Y.AokiT.Komatsubara
S.Satou

I.Arai
S.M.Lee
K.SasaS.EsumiY.MiakeY.Tagishi

T.Katou

M.Kurosawa

K.Furuno
N.Okumura
T.Une

T.Katabuchi
M.OnodaS.KatohInst. of Geoscience
R.AnmaInst. of Applied Physics
A.Uedono

E.KitaH.KudoK.Shima

S.Kuroda

H.Mizubayashi

Inst. of Chemistry
R.SekiInst. of Materials Science
H.IkedaH.Tanimoto

T.Koyano

K.Takita

College of Medical Technology and Nursing
Y.Nagashima

Tandem Accelerator Center
K.Itoh

Li Tian-Xin

Venture Business Lab.
T.Miyazaki

Graduate Students
Doctoral Degree Programs in Physics
Ma Ying-Jun
Y.Sasaki
R.AraiK.Takeda
K.Sekine

H.Sasaki
S.G.Lee
M.Ono,
A.Kiyomichi
W.Iwazaki

N.Kawachi
M.Imanaka
H.Tsuruoka
S.SakaiT.Suguri

T.Jou
M.Yamaguchi
K.Satoh
J.Hirose
Y.TakechiJ.Hasegawa
A.Danmura
T.Yamada
H.Masui
M.Nakazumi

Doctoral Degree Programs in Engineering
K.Ono
Li Changqing

N.UmedaK.Suzuki

S.SakaiN.Ookubo

A.Oyadomari
T.IidaK.Teranishi
S.Numazawa

D.Kasuga
H.SatohN.Umezawa

Doctoral Degree Programs in Education
T.Tsukada

Master's Degree Programs in Sciences and Engineering
S.Yokose
K.KanbeC.Sakurai
Y.Kuroki

T.Iizuka
Y.KoudaM.Ishizuka
T.BannoA.Negishi
Y.Mihara
M.Aramaki
I.AranoDoctoral Degree Programs in Agriculture Sciences
S.Kaburagi- 99 -

Undergraduates
H.AraiT.IkedaN.Kariya
K.Shiga
S.Takagi

A.Tanaka
H.Koubai
S.Miyasaka
M.Nagata

N.YagiT.OhkiT.Suzuki
N.Yoshimaru- 100 -

A.Hatanaka
M.KonnoT.MutohT.Nomiyama

T.Matsuhiro
T.Harigae
H.naitoh
S.Kaminaga