JAEA-Review 2008-054

JAEA-Tokai Tandem Annual Report 2007
April 1, 2007 - March 31, 2008
Department of Research Reactor and Tandem Accelerator
Nuclear Science Research InstituteTokai Research and Development Center
Japan Atomic Energy Agency
Tokai-mura, Naka-gun, Ibaraki-ken(Received September 11, 2008)
The JAEA-Tokai tandem accelerator facility has been used in various research fields of heavy-ion
nuclear science and material science not only by JAEA personnel but also by researchers fromuniversities, institutes and companies. This annual report describes a summary of research activities
carried out in the period between April 1, 2007 and March 31, 2008. The forty-nine summary reports
from users were categorized into seven research/development fields:(1) accelerator operation and development(2) nuclear structure(3) nuclear reaction(4) nuclear chemistry(5) nuclear theory(6) atomic physics and solid state physics(7) radiation effects in materials
Also contained are lists of publications, meetings, technical staff, researchers in JAEA andcooperative researchers with universities.

Keywords : JAEA-Tokai Tandem Accelerator, Operation Results, Nuclear Structure, Nuclear
Reaction, Nuclear Chemistry, Nuclear Theory, Atomic Physics, Solid State Physics, Radiation Effects
in Materials, Progress Report.

Editors : Yuichiro NAGAME, Satoshi CHIBA, Norito ISHIKAWA, Shin-ichi MITSUOKA,
Yosuke TOH, Makoto MATSUDA and Tetsuro ISHIIi

JAEA-Review 2008-054

原子力機構東海タンデム加速器 2007 年度年次報告

日本原子力研究開発機構
東海研究開発センター原子力科学研究所
研究炉加速器管理部（2008 年９月 11 日受理）

原子力機構東海タンデム加速器施設は、重イオンを用いた原子核科学や物質科学などの様々な分野において、原子力機構の職員を初め、大学や研究機関、民間企業の研究者に利用されている。本年次報告書は、2007 年４月１日から 2008 年３月 31 日までの期間に実施された研究活動の要約をまとめたものである。
総数 49 件の要約を下記の７部門に分類した。
（１）加速器の運転状況と開発（２）原子核構造（３）原子核反応（４）核化学（５）原子核理論（６）原子物理及び固体物理（７）材料の照射効果
さらに、発表論文と会議での口頭発表、タンデム加速器に関係する技術者および原子力機構の研究者ならびに大学等の共同研究者の一覧を掲載した。

原子力科学研究所：〒319-1195 茨城県那珂郡東海村白方白根 2-4
編集者：永目 諭一郎、千葉 敏、石川 法人、光岡 真一、藤 暢輔、松田 誠、
石井 哲朗

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JAEA-Review 2008-054

Foreword
This report covers research and development activities with the tandem accelerator, its superconducting
booster and the TRIAC (Tokai Radioactive Ion Accelerator Complex) at JAEA Tokai, for the period of FY
2007 (April 1, 2007 to March 31, 2008). During this period, the tandem accelerator was operated over a
total of 105 days and delivered 23 different ions to the experiments in the fields of nuclear physics, nuclear
chemistry, atomic physics, solid state physics and radiation effects in materials. Fifty-six research programs
were carried out in collaboration with a total of about 240 researchers from universities and research
institutes. The TRIAC was operated for 9 days. The following are some of the highlights in FY 2007.
In the development of the tandem accelerator and the booster, we took a long maintenance period for
replacing the aged coil inside the 180 degree bending magnet in the terminal. In this period, the 10 GHz
in-terminal ECR ion source, NANOGAN, was replaced with the 14.5 GHz ECR ion source,SUPERNANOGAN. The beam-line components at the terminal were also realigned. This alignment greatly
improved the transmission of ion beams through the terminal. As a result, we have achieved theacceleration of a 3 μA proton beam and a 1.3 particle μA fluorine beam.
In research of nuclear reactions, fusion barrier distributions were extracted in the 86Kr + 208Pb reaction,
relating to cold fusion for the production of super-heavy elements Z = 118. Fission fragment mass
distribution in 36S + 238U was measured to study nuclear orientation effects of well-deformed actinides.
In research of nuclear structure, in-beam γ-ray spectroscopy experiments for 36,38Cl, 36S, 168Ta and 188Pt,
and a Coulomb excitation experiment for 100Ru have been made by utilizing the γ-ray detector array,
GEMINI-II; Shape coexistence in 188Pt and band structures of 168Ta have been clarified. By in-beam γ-ray
spectroscopy using heavy-ion transfer reactions, eight Nilsson orbitals in 249Cm, including an L=8 orbital,
were identified. The deformed shell gap at N = 152 was found to be reduced for 246Pu. Energy levels in
255

Fm were established by the α-γ spectroscopy of 259No.

In research of nuclear chemistry, the anion-exchange experiment of Db has been conducted in HF/HNO3
solution with AIDA. The preliminary result on the adsorption of Db on the resin is reported. To obtain moreaccurate data of Db with high statistics, an improved AIDA system, AIDA-II, based on continuous sample
collection and evaporation of effluents, and successive α-particle measurement, has been developed. The
successful oxidation of element 102, No, on an atom-at-a-time scale using the newly developed flow
electrolyte column chromatography is presented.
In the field of nuclear theory, exotic shell structure in the neutron-rich region around N = 28 was exploredby the shell model. The effective interaction was constructed based on general interactions, and thecross-shell interaction was also generated. It was found that the observed spectroscopic factors are
reproduced satisfactorily and there is a strong dependence of them on the tensor force. Hyperon
suppression in hadron-quark mixed phase, stability of the superheavy nuclei and other topics were also
investigated.
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JAEA-Review 2008-054

In research of atomic physics and solid state physics, high resolution measurements were performed for
Coster-Kronig electron spectra from high Rydberg states of Be-like four-electron N and O ions.
Non-destructive on-line Li diffusion measurements are conducted for Li ionic conductors using short-lived
α-emitting radiotracer 8Li produced as a pulsed ion beam from TRIAC. Li-content dependence of diffusion
coefficients observed for β-LiGa suggests that excess Li vacancies induce formation of a defect complex
which may suppress Li motion.
In research of radiation effects in materials, radiation damage process of UO2 and CeO2 ceramics wasinvestigated in order to elucidate the radiation damage process of high burnup nuclear fuels. Surface
morphology change is observed for both ion-irradiated UO2 and CeO2, suggesting that same damage
formation mechanism may be underlying for both materials.

Masao Sataka
Deputy Director
Department of Research Reactor
and Tandem Accelerator

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JAEA-Review 2008-054

Contents
1.

ACCELERATOR OPERATION AND DEVELOPMENT ······················································································· 1

1.1 Operation and usage of tandem accelerator and booster····················································································· 3
M. Sataka, Y. Tsukihashi, S. Hanashima, S. Abe, N. Ishizaki, A. Osa, M. Matsuda, T. Nakanoya, H. Kabumoto,
N. Nakamura, K. Kutsukake, Y. Otokawa, T. Asozu (Dep. of Research Reactor and Tandem Accelerator, JAEA*)

1.2 KEK-JAEA Joint RNB Project ···························································································································· 6
TRIAC Collaboration : Corresponding author, S.C. Jeong (KEK**)

1.3 Impedance measurement of the bending magnet in the Tokai-Tandem high voltage terminal························ 8
S. Hanashima (Dep. of Research Reactor and Tandem Accelerator, JAEA)

1.4 Beam acceleration results of the new 14.5 GHz in-terminal ECR ion source·················································10
M. Matsuda, T. Asozu, T. Nakanoya, Y. Otokawa, K. Kutsukake, S. Hanashima (Dep. of Research Reactor
and Tandem Accelerator, JAEA)

1.5 Study for installing a beam profile monitor in the high-voltage terminal························································12T. Asozu, M. Matsuda (Dep. of Research Reactor and Tandem Accelerator, JAEA)

1.6 Performance test of low beta superconducting twin quarter wave resonator ··················································14
H. Kabumoto, S. Takeuchi, N. Ishizaki, M. Matsuda, Y. Otokawa (Dep. of Research Reactor and Tandem
Accelerator, JAEA)

1.7 Improvement of acceleration electric fields of superconducting booster resonators
using high pressure water jet rinse·····················································································································16
H. Kabumoto, S. Takeuchi, N. Ishizaki (Dep. of Research Reactor and Tandem Accelerator, JAEA)
T. Yoshida, T. Ishiguro, K. Yamaguchi (ATOX Co., LTD.)

1.8 Status of the JAEA-ISOL····································································································································17
Y. Otokawa, A. Osa (Dep. of Research Reactor and Tandem Accelerator, JAEA) T.K. Sato, S. Ichikawa(Advanced Science Research Center, JAEA)

Y. Fuchi (KEK)

1.9 Development of ion source for the JAEA-ISOL ································································································19
A. Osa, Y. Otokawa (Dep. of Research Reactor and Tandem Accelerator, JAEA)
T.K. Sato, S. Ichikawa (Advanced Science Research Center, JAEA)

1.10 Electrostatic collection method for identification of natural radon (222Rn) ·····················································21
M. Nakamura, M. Matsuda, N. Ishizaki, A. Osa, T. Nakanoya, H. Kabumoto, K. Kutsukake, Y. Otokawa,
T. Asozu (Dep. of Research Reactor and Tandem Accelerator, JAEA) T. Ishii, M. Asai (Advanced
Science Research Center, JAEA) T. Ohkura (Dep. of Radiation Protection, JAEA)

2.

NUCLEAR STRUCTURE········································································································································23

2.1 Study of high-spin states in 36S and 36Cl·············································································································25
E. Ideguchi, M.L. Liu, Y. Zheng (University of Tokyo) T. Morikawa, S. Mitarai (Kyushu University)
Y. Toh, M. Koizumi, A. Kimura, M. Oshima, K. Furutaka (Nuclear Science and Engineering Directorate, JAEA)
Y. Hatsukawa (Quantum Beam Science Directorate, JAEA) B. Cederwall (Royal Institute of Technology)
H. Kusakari (Chiba University) M. Sugawara (Chiba Institute of Technology)

2.2 Spectroscopy of 38Cl············································································································································27
T. Morikawa, S. Mitarai (Kyushu University) E. Ideguchi, M.L. Liu, Y. Zheng (University of Tokyo)v

JAEA-Review 2008-054

M. Oshima, M. Koizumi, Y. Toh, A. Kimura, H. Harada, K. Furutaka, S. Nakamura, F. Kitatani (Nuclear
Science and Engineering Directorate, JAEA) Y. Hatsukawa (Quantum Beam Science Directorate, JAEA)
A. Osa (Dep. of Research Reactor and Tandem Accelerator, JAEA) M. Sugawara (Chiba Institute ofTechnology) H. Kusakari (Chiba University)

2.3 Study of low-lying collective modes in 100Ru by multiple Coulomb excitation··············································29
Y. Toh, M. Koizumi, M. Oshima, A. Kimura, H. Harada, K. Furutaka, F. Kitatani, S. Nakamura (Nuclear Scienceand Engineering Directorate, JAEA) Y. Hatsukawa (Quantum Beam Science Directorate, JAEA) A. Osa(Dep. of Research Reactor and Tandem Accelerator, JAEA) M. Sugawara (Chiba Institute of Technology)
T. Morikawa (Kyushu University)

2.4 In-beam gamma spectroscopy of 168Ta···············································································································31
Y.H. Qiang, Y.H. Zhang, X.H. Zhou (Institute of Modern Physics, Chaina) M. Oshima, M. Koizumi, Y. Toh,
A. Kimura, H. Harada, K. Furutaka, F. Kitatani, S. Nakamura, M. Ohta, K. Hara, T. Kin (Nuclear Scienceand Engineering Directorate, JAEA) Y. Hatsukawa (Quantum Beam Science Directorate, JAEA)
J. Meng (Peking University)

2.5 Isomers in neutron-rich tantalum isotopes ·········································································································33
T. Shizuma, T. Hayakawa (Quantum Beam Science Directorate, JAEA) T. Ishii, H. Makii (Advanced Science
Research Center, JAEA) M. Matsuda (Dep. of Research Reactor and Tandem Accelerator, JAEA)
E. Ideguchi (University of Tokyo) T. Morikawa (Kyushu University)

2.6 Prolate and oblate shape co-existence in 188Pt····································································································34
X.H. Zhou, Y.H. Zhang (Institute of Modern Physics, Chaina) M. Oshima, Y. Toh, M. Koizumi (Nuclear Scienceand Engineering Directorate, JAEA) A. Osa (Dep. of Research Reactor and Tandem Accelerator, JAEA)
Y. Hatsukawa (Quantum Beam Science Directorate, JAEA) M. Sugawara (Chiba Institute of Technology)

2.7 Gamma-rays in ground-state band of 246Pu········································································································36
H. Makii, T. Ishii, M. Asai, K. Tsukada, A. Toyoshima, H. Toume, S. Ichikawa (Advanced Science ResearchCenter, JAEA) M. Matsuda (Dep. of Research Reactor and Tandem Accelerator, JAEA) A. Makishima(National Defence Medical College) J. Kaneko, M. Ogawa (Komazawa University)
S. Shigematsu, T. Kohno (Tokyo Institute of Technology)

2.8 Quasi-particle states in 249Cm measured by in-beam γ-ray spectroscopy························································38
T. Ishii, H. Makii, M. Asai, K. Tsukada, A. Toyoshima, H. Toume (Advanced Science Research Center, JAEA)
M. Matsuda (Dep. of Research Reactor and Tandem Accelerator, JAEA) A. Makishima (National Defence
Medical College) S. Shigematsu, T. Kohno (Tokyo Institute of Technology) J. Kaneko, M. Ogawa(Komazawa University) T. Shizuma (Quantum Beam Science Directorate, JAEA)
I. Hossain (Osaka University)

2.9 Alpha-gamma coincidence spectroscopy of 259No····························································································40
M. Asai, K. Tsukada, Y. Ishii, A. Toyoshima, T. Ishii, I. Nishinaka, Y. Nagame, Y. Kasamatsu (Advanced
Science Research Center, JAEA) M. Sakama (University of Tokushima) M. Shibata, H. Hayashi(Nagoya University) H. Haba (RIKEN***) Y. Kojima (Hiroshima University)

2.10 Decay study on fission products with on-line isotope separator········································································42
M. Shibata (Nagoya University) A. Osa (Dep. of Research Reactor and Tandem Accelerator, JAEA)
M. Asai, T.K. Sato (Advanced Science Research Center, JAEA)
M. Oshima, A. Kimura, M. Koizumi (Nuclear Science and Engineering Directorate, JAEA)

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JAEA-Review 2008-054

2.11 A gas cell for on-line laser spectroscopy of radioactive isotopes of refractory elements ·································44
H. Iimura, M. Miyabe, M. Oba, M. Koizumi (Nuclear Science and Engineering Directorate, JAEA)

2.12 On-line test of RI ion trap system ························································································································46
H. Makii, T. Ishii, D. Nagae, T.K. Sato, S. Ichikawa (Advanced Science Research Center, JAEA)
A. Osa (Dep. of Research Reactor and Tandem Accelerator, JAEA)

2.13 Development of spin-polarized radioactive nuclei around 132Sn for nuclear spectroscopy·····························48
Y. Hirayama, S.C. Jeong, H. Miyatake, Y.X. Watanabe, N. Imai, H. Ishiyama, I. Katayama, H. Kawakami (KEK)
K. Matsuta, M. Mihara, D. Nishimura, T. Shimoda (Osaka University) T. Hashimoto, S. Ichikawa, T. Ishii, H. Makii,
S. Mitsuoka, D. Nagae, K. Nishio, T.K. Sato (Advanced Science Research Center, JAEA)
T. Izumikawa, T. Otsubo (Niigata University) D. Kameda (RIKEN) H. Kawamura (Rikkyo University)
S. Momota (Kochi University of Technology) A. Osa (Dep. of Research Reactor and Tandem Accelerator, JAEA)

3.

NUCLEAR REACTION ·········································································································································· 49

3.1 Measurement of quasi-elastic backscattering in 58Ni+124Sn············································································51
Y.X. Watanabe, S.C. Jeong, Y. Hirayama, N. Imai, H. Ishiyama, H. Miyatake (KEK)
S. Mitsuoka, K. Nishio, T. Hashimoto, H. Ikezoe (Advanced Science Research Center, JAEA)

3.2 Barrier distribution of quasi-elastic backscattering in 86Kr+208Pb·····································································53
S. Mitsuoka, H. Ikezoe, K. Nishio, T. Hashimoto (Advanced Science Research Center, JAEA)
Y.X. Watanabe, S.C. Jeong, Y. Hirayama, N. Imai, H. Ishiyama, H. Miyatake (KEK)

3.3 Effects of nuclear orientation on fission fragment mass distributions in the reaction of 36S + 238U ···············54
K. Nishio, H. Ikezoe, S. Mitsuoka, I. Nishinaka, Y. Nagame (Advanced Science Research Center, JAEA)
Y.X. Watanabe (KEK) T. Ohtsuki, K. Hirose (Tohoku University)

3.4 Fusion reaction 82Kr + 140Ce using JAEA recoil mass separator ······································································56
K. Nishio, H. Ikezoe, S. Mitsuoka, I. Nishinaka, T. Hashimoto, T.K. Sato (Advanced Science Research Center, JAEA)
M. Matsuda (Dep. of Research Reactor and Tandem Accelerator, JAEA) Y.X. Watanabe (KEK)

3.5 R&D for a test of time reversal symmetry experiment using polarized nuclei ···············································58
J. Murata, T. Akiyama, M. Hata, Y. Ikeda, H. Kawamura, K. Ninomiya, M. Nitta, E. Seitaibashi, T. Toyoda(Rikkyo University) Y. Hirayama, H. Miyatake (KEK) T. Ishii, S. Mitsuoka, D. Nagae (Advanced
Science Research Center, JAEA) D. Kameda (RIKEN)

4.

NUCLEAR CHEMISTRY ······································································································································· 61

4.1 Oxidation of divalent nobelium (No) to the trivalent state using an electrochemistry apparatus···················63
A. Toyoshima, Y. Kasamatsu, K. Tsukada, M. Aasi, Y. Ishii, H. Toume, Y. Nagame (Advanced Science ResearchCenter, JAEA) Y. Kitatsuji (Nuclear Science and Engineering Directorate, JAEA) H. Haba (RIKEN)
K. Akiyama (Tokyo Metropolitan University) K. Ooe, W. Sato, A. Shinohara (Osaka University)

4.2 Adsorption of element 105, Db, on the anion-exchange resin in HF/HNO3 media········································65
Y. Kasamatsu, A. Toyoshima, M. Asai, K. Tsukada, Y. Ishii, H. Toume, I. Nishinaka, T.K. Sato, Y. Nagame(Advanced Science Research Center, JAEA)

H. Haba, H. Kikunaga (RIKEN)

K. Akiyama (Tokyo

Metropolitan University) S. Goto, T. Ishikawa, H. Kudo (Niigata University) W. Sato, K. Ooe, T. Kuribayashi,
A. Shinohara (Osaka University) N. Kinoshita, M. Arai, A. Yokoyama (Kanazawa University)
M. Sakama (University of Tokushima) Z. Qin (Institute of Modern Physics, Chaina)

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JAEA-Review 2008-054

Ch.E. Düllmann (Gesellschaft für Schwerionenforschung, Germany)

4.3 New apparatus AIDA-II for the study of aqueous chemistry of the transactinide elements···························67
K. Tsukada, Y. Kasamatsu, M. Asai, A. Toyoshima, Y. Ishii, H. Toume, Y. Nagame(Advanced Science Research Center, JAEA)

4.4 Production of radioactive tracers for chemistry of transactinide elements ······················································69
S. Goto, T. Ishikawa, T. Kawasaki, T. Hasegawa, H. Kudo (Niigata University)
K. Tsukada, M. Asai, A. Toyoshima, Y. Nagame (Advanced Science Research Center, JAEA)

5.

NUCLEAR THEORY··············································································································································· 71

5.1 Single-particle property of unstable nuclei around N=28 from the spectroscopic factor
calculated with a new shell model interaction··································································································73
Y. Utsuno (Advanced Science Research Center, JAEA) B.A. Brown (Michigan State University)
T. Otsuka (University of Tokyo) M. Honma (University of Aizu) T. Mizusaki (Senshu University)

5.2 Analysis of inclusive (K-, K+) reaction with semi-classical distorted wave model ·········································75
S. Hashimoto (Advanced Science Research Center, JAEA) M. Kohno (Kyushu Dental College)
K. Ogata, M. Kawai (Kyushu University)

5.3 Hyperon suppression in hadron-quark mixed phase·························································································77
T. Maruyama, S. Chiba (Advanced Science Research Center, JAEA) T. Tatsumi (Kyoto University)
H.-J. Schulze (Istituto Nazionare Fisica Nucleare, Italy)

5.4 Decay modes and limit of existence of nuclei in the superheavy nuclidic region···········································79
H. Koura, S. Chiba (Advanced Science Research Center, JAEA)
T. Tachibana (Waseda University Senior High School)

5.5 Direct and semi-direct capture in the low-energy (n,γ) reactions of neutron-rich Tin isotopes
and its implications for the r-process nucleosynthesis······················································································81
S. Chiba, H. Koura, T. Maruyama (Advanced Science Research Center, JAEA) T. Hayakawa (Quantum
Beam Science Directorate, JAEA) T. Kawano (Los Alamos National Laboratory)
T. Kajino (National Astronomical Observatory of Japan)

5.6 Soft-rotator model analysis for medium-heavy nuclei and systematics of the Hamiltonian parameters·······83
S. Kunieda, K. Shibata, A. Ichihara, O. Iwamoto, N. Iwamoto (Nuclear Science and Engineering Directorate,
JAEA) S. Chiba (Advanced Science Research Center, JAEA) E.Sh. Sukhovitskii (Joint Institute forEnergy and Nuclear Research, Belarus)

6.

ATOMIC PHYSICS AND SOLID STATE PHYSICS····························································································· 85

6.1 Coster-Kronig electrons from N3+ Rydberg states produced in high-energy collisions with He····················87
K. Kawatsura, K. Takahiro, K. Ozaki (Kyoto Institute of Technology) M. Sataka (Dep. of Research Reactor
and Tandem Accelerator, JAEA) M. Imai, H. Shibata (Kyoto University) H. Sugai (Advanced Science
Research Center, JAEA) K. Komaki (National Center for University Entrance Examination)

6.2 Charge state distribution of sulfur ions after penetration of C–foil targets (V)················································89
M. Imai, H. Shibata (Kyoto University) M. Sataka (Dep. of Research Reactor and Tandem Accelerator, JAEA)
K. Nishio, H. Sugai (Advanced Science Research Center, JAEA) K. Kawatsura, K. Takahiro (Kyoto Instituteof Technology) K. Komaki (National Center for University Entrance Examinations)

6.3 Diffusion of 8Li short-lived radiotracer in Li ionic conductors of NaTl-type intermetallic compounds················91viii

JAEA-Review 2008-054

H. Sugai, S. Okayasu, S. Ichikawa, K. Nishio, S. Mitsuoka, T.K. Sato, T. Hashimoto (Advanced Science
Research Center, JAEA) M. Sataka, T. Nakanoya, A. Osa (Dep. of Research Reactor and Tandem
Accelerator, JAEA) S.C. Jeong, I. Katayama, H. Kawakami, Y.X. Watanabe, H. Ishiyama, N. Imai,
Y. Hirayama, H. Miyatake (KEK) Takanori Hashimoto, M. Yahagi (Aomori University)

7.

RADIATION EFFECTS IN MATERIALS·············································································································· 93

7.1 Character and accumulation effects of ion tracks in UO2 and CeO2 under irradiation
with high energy ions ·········································································································································95
T. Sonoda, M. Kinoshita (Central Research Institute of Electric Power Industry) N. Ishikawa (Advanced
Science Research Center, JAEA ) M. Sataka (Dep. of Research Reactor and Tandem Accelerator, JAEA)
K. Yasunaga (Kyushu University) A. Iwase (Osaka Prefecture University)

7.2 Evaluation of radiation damage in CeO2 created by high-density electronic energy deposition····················97
N. Ishikawa (Advanced Science Research Center, JAEA)

7.3 Evaluation of radiation damage in CeO2 created by Xe-implantation·····························································99
N. Ishikawa (Advanced Science Research Center, JAEA)
M. Matsuda (Dep. of Research Reactor and Tandem Accelerator, JAEA)

7.4 Atomic structure of ion tracks in magnesium aluminate spinel irradiated with swift heavy ions················101
K. Yasuda, T. Yamamoto, S. Kawasoe, M. Eto, S. Matsumura (Kyushu University)
N. Ishikawa (Advanced Science Research Center, JAEA)

7.5 Surface amorphization in single crystalline α-Al2O3 induced by swift heavy ion········································103
N. Okubo, T. Nakazawa, S. Jitsukawa (Nuclear Science and Engineering Directorate, JAEA)
M. Sataka (Dep. of Research Reactor and Tandem Accelerator, JAEA)

7.6 Modifications of atomic structure and optical properties of cuprite by high-energy ion impact··················105
N. Matsunami (Nagoya University) M. Sataka (Dep. of Research Reactor and Tandem Accelerator, JAEA)
S. Okayasu, N. Ishikawa (Advanced Science Research Center, JAEA)
M. Tazawa, H. Kakiuchida (National Institute for Advanced Industrial Science and Technologhy)

7.7 Magnetic domains induced by swift heavy ion irradiation in FeRh alloys····················································107
A. Iwase, Y. Zushi, N. Fujita, T. Matsui, F. Hori (Osaka Prefecture University) N. Ishikawa (Advanced
Science Research Center, JAEA) S. Seki (Osaka University)

7.8 Nanostructural changes of iron disilicides (β-FeSi2) thin films by high-energy heavy ion irradiation········109
M. Sasase (The Wakasa Wan Energy Research Center)
S. Okayasu (Advanced Science Research Center, JAEA)* JAEA : Japan Atomic Energy Agency** KEK : High Energy Accelerator Research organization*** RIKEN : The Institute of Physical and Chemical Research

8.

PUBLICATION IN JOURNAL AND PROCEEDINGS, AND CONTRIBUTIONTO SCIENTIFIC MEETINGS ·······························································································································111

8.1
8.2
8.3
8.4

Accelerator Operation and Development ········································································································113
Nuclear Structure···············································································································································115
Nuclear Reaction ···············································································································································119
Nuclear Chemistry·············································································································································123ix

JAEA-Review 2008-054

8.5 Nuclear Theory ··················································································································································126
8.6 Atomic Physics and Solid State Physics ··········································································································133
8.7 Radiation Effects in Materials···························································································································134
9.

PERSONNEL AND COMMITTEE······················································································································· 137

9.1 Personnel····························································································································································139
9.2 Research Planning and Assessment Committee······························································································143
10. COOPERATIVE RESEARCHES AND COMMON USE PROGRAM IN JAEA ·············································· 145

10.1 Cooperative Researches List···························································································································147
10.2 Common Use Program in JAEA····················································································································149x

JAEA-Review 2008-054目

次

1. 加速器の運転状況及び開発································································· 1
1.1 タンデム加速器とブースターの運転と利用 ················································ 3
左高正雄、月橋芳廣、花島 進、阿部信市、石崎暢洋、長 明彦、松田 誠、中野谷孝充、株本裕史、
中村暢彦、沓掛健一、乙川義憲、遊津拓洋（日本原子力研究開発機構 研究炉加速器管理部）

1.2 KEK-JAEA 共同 RNB 計画 ································································· 6
鄭 淳讃（高エネルギー加速器研究機構）

1.3 東海タンデム加速器高電圧端子内偏向磁石のインピーダンス測定 ···························· 8
花島 進（日本原子力研究開発機構 研究炉加速器管理部）

1.4 新 14.5GHz 高電圧端子内 ECR イオン源のビーム加速 ······································· 10
松田 誠、遊津拓洋、中野谷孝充、乙川義憲、沓掛健一、花島 進（日本原子力研究開発機構
研究炉加速器管理部）

1.5 ビームプロファイルモニターの高電圧端子への設置に関する検討 ··························· 12
遊津拓洋、松田 誠（日本原子力研究開発機構 研究炉加速器管理部）

1.6 低β超伝導 2 芯 1/4 波長型空洞共振器の性能試験 ········································· 14
株本裕史、竹内末広、石崎暢洋、松田 誠、乙川義憲（日本原子力研究開発機構 研究炉加速器管理部）

1.7 高圧純水洗浄による超伝導ブースターの電界性能改善 ····································· 16
株本裕史、竹内末広、石崎暢洋（日本原子力研究開発機構 研究炉加速器管理部）
吉田崇宏、石黒貴之、山口和司（㈱アトックス）

1.8 JAEA-ISOL の現状 ····································································· 17
乙川義憲、長 明彦（日本原子力研究開発機構 研究炉加速器管理部）（日本原子力研究開発機構 先端基礎研究センター）

佐藤哲也、市川 進一

渕 好秀（高エネルギー加速器研究機構）

1.9 JAEA-ISOL 用イオン源の開発 ···························································· 19
長 明彦、乙川義憲（日本原子力研究開発機構 研究炉加速器管理部）
佐藤哲也、市川 進一（日本原子力研究開発機構 先端基礎研究センター）

1.10 静電気捕集法による天然ラドン(222Rn)の同定 ············································· 21
中村暢彦、松田 誠、石崎暢洋、長 明彦、中野谷孝充、株本裕史、沓掛健一、乙川義憲、
遊津拓洋（日本原子力研究開発機構 研究炉加速器管理部）
開発機構 先端基礎研究センター）

石井哲朗、浅井雅人（日本原子力研究

大倉毅史（日本原子力研究開発機構 放射線管理部）

2. 原子核構造 ············································································· 23
2.1

36

S および 36Cl の高スピン状態の研究 ···················································· 25
井手口栄治、柳 敏良、鄭 勇（東京大学）

森川恒安、御手洗志郎（九州大学）

藤 暢輔、

小泉光生、木村 敦、大島真澄、古高和禎（日本原子力研究開発機構 原子力基礎工学研究部門）
初川雄一（日本原子力研究開発機構 量子ビーム応用研究部門）
草刈英榮（千葉大学）

2.2

Bo Cederwall（王立工科大学）

菅原昌彦（千葉工業大学）

38

Cl の核分光········································································· 27
森川恒安、御手洗志郎（九州大学）

井手口栄治、柳 敏良、鄭 勇（東京大学）

大島真澄、小泉光生、

藤 暢輔、木村 敦、原田秀郎、古高和禎、中村詔司、北谷文人（日本原子力研究開発機構 原子力基礎工学
研究部門）

初川雄一（日本原子力研究開発機構 量子ビーム応用研究部門）

研究開発機構 研究炉加速器管理部）

菅原昌彦（千葉工業大学）xi

長 明彦（日本原子力

草刈英榮（千葉大学）

JAEA-Review 2008-054

2.3 多重クーロン励起による 100Ru の低励起集団モードの研究 ·································· 29
藤 暢輔、小泉光生、大島真澄、木村 敦、原田秀郎、古高和禎、北谷文人、中村詔司（日本原子力研究開発機構 原子力基礎工学研究部門）

2.4

初川雄一（
（日本原子力研究開発機構

量子ビーム応用研究部門）

長 明彦（日本原子力研究開発機構 研究炉加速器管理部）

菅原昌彦（千葉工業大学）

森川恒安（九州大学）

168

Ta のインビームガンマ線分光························································· 31

Y.H. Qiang、Y.H. Zhang、X.H. Zhou（中国近代物理研究所）

大島真澄、小泉光生、藤 暢輔、

木村 敦、原田秀郎、古高和禎、北谷文人、中村詔司、太田雅之、原 かおる、金 政浩（日本原子力研究開発機構 原子力基礎工学研究部門）

初川雄一（日本原子力研究開発機構 量子ビーム応用研究部門）

J. Meng(北京大学)

2.5 中性子過剰 Ta 同位体のアイソマー······················································ 33
静間俊行、早川岳人（日本原子力研究開発機構 量子ビーム応用研究部門）
原子力研究開発機構 先端基礎研究センター）
井手口栄治（東京大学）

2.6

松田 誠（日本原子力研究開発機構 研究炉加速器管理部）

森川恒安（九州大学）

188

Pt の葉巻型と蜜柑型変形共存························································· 34

X.H. Zhou、Y.H. Zhang（中国近代物理研究所）開発機構 原子力基礎工学研究部門）

大島真澄、藤 暢輔、小泉光生（日本原子力研究長 明彦（日本原子力研究開発機構 研究炉加速器管理部）

初川雄一（日本原子力研究開発機構 量子ビーム応用研究部門）

2.7

石井哲朗、牧井宏之（日本

菅原昌彦（千葉工業大学）

246

Pu の基底状態バンドのγ線遷移······················································ 36

牧井宏之、石井哲朗、浅井雅人、塚田和明、豊嶋厚史、當銘勇人、市川進一（日本原子力研究開発機構
先端基礎研究センター）（防衛医科大学）

松田 誠（日本原子力研究開発機構 研究炉加速器管理部）

金子順一、小川雅生（駒沢大学）

牧嶋章泰

重松宗一郎、河野俊之（東京工業大学）

2.8 インビームγ線分光による 249Cm の準粒子状態 ··········································· 38
石井哲朗、牧井宏之、浅井雅人、塚田和明、豊嶋厚史、當銘勇人（日本原子力研究開発機構 先端基礎研究センター）

松田 誠（日本原子力研究開発機構 研究炉加速器管理部）

重松宗一郎、河野俊之（東京工業大学）
開発機構 量子ビーム応用研究部門）

2.9

金子順一、小川雅生（駒沢大学）

牧嶋章泰（防衛医科大学）
静間俊行（日本原子力研究

I. Hossain（大阪大学）

259

No のα-γ同時計数測定 ····························································· 40

浅井雅人、塚田和明、石井康雄、豊嶋厚史、石井哲朗、西中一朗、永目諭一郎、笠松良崇（日本原子力
研究開発機構 先端基礎研究センター）
羽場宏光（理化学研究所）

阪間 稔（徳島大学）

柴田理尋、林 裕晃（名古屋大学）

小島康明（広島大学）

2.10 オンライン同位体分離装置を用いた核分裂生成物の壊変特性の研究 ························· 42
柴田理尋（名古屋大学）

長 明彦（日本原子力研究開発機構 研究炉加速器管理部）

浅井雅人、佐藤哲也（日本原子力研究開発機構 先端基礎研究センター）
大島真澄、木村 敦、小泉光生（日本原子力研究開発機構 原子力基礎工学研究部門）

2.11 高融点元素の放射性同位体のオンライン・レーザー分光のためのガスセルの開発 ·············· 44
飯村秀紀、宮部昌文、大場正規、小泉光生（日本原子力研究開発機構 原子力基礎工学研究部門）

2.12 RI イオントラップ装置のオンライン試験 ················································ 46
牧井宏之、石井哲朗、長江大輔、佐藤哲也、市川進一（日本原子力研究開発機構 先端基礎研究センター）
長 明彦（日本原子力研究開発機構 研究炉加速器管理部）

2.13 核分光を目的とした核スピン偏極した 132Sn 近傍核の開発 ·································· 48
平山賀一、鄭 淳讃、宮武宇也、渡辺 裕、今井伸明、石山博恒、片山一郎、川上宏金（高エネルギーxii

JAEA-Review 2008-054

加速器研究機構）

松多建策、三原基嗣、西村大樹、下田 正（大阪大学）

橋本尚志、市川進一、石井哲朗、

牧井宏之、光岡真一、長江大輔、西尾勝久、佐藤哲也（日本原子力研究開発機構 先端基礎研究センター）
泉川卓司、大坪 隆（新潟大学）
百田佐多生（高知工科大学）

亀田大輔（理化学研究所）

川村広和（立教大学）

長 明彦（日本原子力研究開発機構 研究炉加速器管理部）

3. 原子核反応 ············································································· 49
3.1

58

Ni+124Sn の後方準弾性散乱の測定 ······················································ 51
渡辺 裕、鄭 淳讃、平山賀一、今井伸明、石山博恒、宮武宇也（高エネルギー加速器研究機構）
光岡真一、西尾勝久、橋本尚志、池添 博（日本原子力研究開発機構 先端基礎研究センター）

3.2

86

Kr+208Pb 反応における後方準弾性散乱の障壁分布········································· 53
光岡真一、池添 博、西尾勝久、橋本尚志（日本原子力研究開発機構 先端基礎研究センター）
渡辺 裕、鄭 淳讃、平山賀一、今井伸明、石山博恒、宮武宇也（高エネルギー加速器研究機構）

3.3

36

S + 238U 反応における標的原子核 238U の向きの効果······································· 54
西尾勝久、池添 博、光岡真一、西中一郎、永目諭一郎（日本原子力研究開発機構 先端基礎研究センター）
渡辺 裕（高エネルギー加速器研究機構）

大槻 勤、廣瀬健太郎（東北大学）

3.4 JAEA 反跳生成核分離装置を用いた融合反応 82Kr+238U の研究································· 56
西尾勝久、池添 博、光岡真一、西中一郎、橋本尚志、佐藤哲也（日本原子力研究開発機構
先端基礎研究センター）
松田 誠（日本原子力研究開発機構 研究炉加速器管理部）
渡辺 裕（高エネルギー加速器研究機構）

3.5 偏極核を用いた時間反転対称性の破れ探索実験の基礎開発 ································· 58
村田次郎、秋山岳伸、秦 麻記、池田友樹、川村広和、二宮一史、新田 稔、聖代橋悦子、
豊田健司（立教大学）

平山賀一、宮武宇也（高エネルギー加速器研究機構）

長江大輔（日本原子力研究開発機構 先端基礎研究センター）

石井哲朗、光岡真一、

亀田大輔（理化学研究所）

4. 核化学 ················································································· 61
4.1 電気化学分析装置を用いたノーベリウム(No)の酸化反応 ··································· 63
豊嶋厚史、笠松良崇、塚田和明、浅井雅人、石井康雄、當銘勇人、永目諭一郎（日本原子力研究開発機構
先端基礎研究センター）
羽場宏光（理化学研究所）

北辻章浩（日本原子力研究開発機構 原子力基礎工学研究部門）
秋山和彦（首都大学東京）

大江一弘、佐藤 渉、篠原 厚（大阪大学）

4.2 HF/HNO3 溶液中での 105 番元素(Db)の陰イオン交換樹脂への吸着性 ·························· 65
笠松良崇、豊嶋厚史、浅井雅人、塚田和明、石井康雄、當銘勇人、西中一朗、佐藤哲也、永目諭一郎（日本原子力研究開発機構 先端基礎研究センター）
秋山和彦（首都大学東京）

羽場宏光、菊永英寿（理化学研究所）

後藤真一、石川 剛、工藤久昭（新潟大学）

佐藤 渉、大江一弘、

栗林隆宏、篠原 厚（大阪大学）

木下哲一、荒井美和子、横山明彦（金沢大学）

Z. Qin（中国近代物理研究所）

Christoph E. Düllman（ドイツ重イオン研究所）

阪間 稔（徳島大学）

4.3 超アクチノイド元素の溶液化学的研究のための新実験装置 AIDA-Ⅱ·························· 67
塚田和明、笠松良崇、浅井雅人、豊嶋厚史、石井康雄、當銘勇人、永目諭一郎（日本原子力研究開発機構
先端基礎研究センター）

4.4 超アクチノイド元素化学のための放射性トレーサーの製造 ································· 69
後藤真一、石川 剛、川﨑拓馬、長谷川太一、工藤久昭（新潟大学）
塚田和明、浅井雅人、豊嶋厚史、永目諭一郎（日本原子力研究開発機構 先端基礎研究センター）

5. 原子核理論 ············································································· 71
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5.1 新しい殻模型相互作用で計算されたスペクトロスコピック因子による中性子数 28 近辺の不安定核の一粒子的性質 ·············································· 73
宇都野 穣（日本原子力研究開発機構 先端基礎研究センター）
大塚孝治（東京大学）

本間道雄（会津大学）-

B.A. Brown（ミシガン州立大学）

水崎高浩（専修大学）+

5.2 半古典歪曲波模型による包括的 (K , K ) 反応解析 ········································ 75
橋本慎太郎（日本原子力研究開発機構 先端基礎研究センター）

河野道郎（九州歯科大学）

緒方一介、河合光路（九州大学）

5.3 ハドロン−クォーク混合相中でのハイペロン抑制 ·········································· 77
丸山敏毅、千葉 敏（日本原子力研究開発機構 先端基礎研究センター）
H.-J. Schulze（イタリア国立核物理研究所）

巽 敏隆（京都大学）

5.4 超重核領域に於ける原子核の崩壊様式と存在限界 ········································· 79
小浦寛之、千葉 敏（日本原子力研究開発機構 先端基礎研究センター）
橘 孝博（早稲田大学高等学院）

5.5 Sn 領域における直接・半直接中性子捕獲と r 過程元素合成への影響························· 81
千葉 敏、小浦寛之、丸山敏毅（日本原子力研究開発機構 先端基礎研究センター）
早川岳人（日本原子力研究開発機構 量子ビーム研究応用部門）

河野俊彦（ロスアラモス国立研究所）

梶野敏貴（国立天文台）

5.6 中重核に対する軟回転体模型解析とハミルトニアンパラメータの系統性 ····················· 83
国枝 賢、柴田恵一、市原 晃、岩本 修、岩本信之（日本原子力研究開発機構 原子力基礎工学研究部門）
千葉 敏（日本原子力研究開発機構 先端基礎研究センター）
E.Sh. Sukhovitskii（エネルギー及び原子核共同研究所（ベラルーシ））

6. 原子物理及び固体物理···································································· 85
6.1 He 原子との高エネルギー衝突による N3+リュドベリ状態からのコスター・クロニッヒ電子 ······ 87
川面 澄、高廣克己、尾﨑孝一（京都工芸繊維大学）
研究炉加速器管理部）

左高正雄（日本原子力研究開発機構

今井 誠、柴田裕実（京都大学）

先端基礎研究センター）

須貝宏行（日本原子力研究開発機構

小牧研一郎（大学入試センター）

6.2 炭素薄膜通過後の硫黄イオンの電荷分布（Ⅴ） ·········································· 89
今井 誠、柴田裕実（京都大学）

左高正雄（日本原子力研究開発機構 研究炉加速器管理部）

西尾勝久、須貝宏行（日本原子力研究開発機構 先端基礎研究センター）
川面 澄、高廣克己（京都工芸繊維大学）

小牧研一郎（大学入試センター）

6.3 NaTl 型金属間化合物 Li イオン導電体中の 8Li 短寿命核トレーサーの拡散 ···················· 91
須貝宏行、岡安 悟、市川進一、西尾勝久、光岡真一、佐藤哲也、橋本尚志（日本原子力研究開発機構
先端基礎研究センター）
研究炉加速器管理部）

左高正雄、中野谷孝充、長 明彦（日本原子力研究開発機構
鄭 淳讃、片山一郎、川上宏金、渡辺 裕、石山博恒、今井伸明、平山賀一、

宮武宇也（高エネルギー加速器研究機構）

橋本恭能、矢萩正人（青森大学）

7. 材料の照射効果·········································································· 93
7.1 高エネルギーイオン照射により UO2 と CeO2 中に発生するイオントラックの特徴と蓄積効果······ 95
園田 健、木下幹康（電力中央研究所）

石川法人（日本原子力研究開発機構 先端基礎研究センター）

左高正雄（日本原子力研究開発機構 研究炉加速器管理部）

安永和史（九州大学）

岩瀬彰宏（大阪府立大学）

7.2 高密度電子的エネルギー付与による CeO2 の照射損傷の評価································· 97xiv

JAEA-Review 2008-054

石川法人（日本原子力研究開発機構 先端基礎研究センター）

7.3 Xe ガス原子注入による CeO2 の照射損傷の評価 ············································ 99
石川法人（日本原子力研究開発機構 先端基礎研究センター）
松田 誠（日本原子力研究開発機構 研究炉加速器管理部）

7.4 高速重イオン照射したマグネシア・アルミネート・スピネル中のイオントラックの原子構造·· 101
安田和弘、山本知一、川副慎治、江藤基稀、松村 晶（九州大学）
石川法人（日本原子力研究開発機構 先端基礎研究センター）

7.5 単結晶α-Al2O3 における高エネルギー重イオン照射による表面非晶質化···················· 103
大久保成彰、中沢哲也、實川資朗（日本原子力研究開発機構 原子力基礎工学研究部門）
左高正雄（日本原子力研究開発機構 先端基礎研究センター）

7.6 高エネルギーイオン照射による酸化銅の原子構造・光学特性改質 ························· 105
松波紀明（名古屋大学）

左高正雄（日本原子力研究開発機構 先端基礎研究センター）

石川法人（日本原子力研究開発機構 先端基礎研究センター）

岡安 悟、

田澤真人、垣内田 洋（産業技術総合研究所）

7.7 高速重イオン照射によって鉄ロジウム合金中に生成された磁区構造 ······················· 107
岩瀬彰宏、圖子善大、藤田直樹、松井利之、堀 史説（大阪府立大学）開発機構 先端基礎研究センター）

石川法人（日本原子力研究関 修平（大阪大学）

7.8 高エネルギー重イオン照射によるシリサイド半導体の構造変化 ··························· 109
笹瀬雅人（若狭湾エネルギー研究センター）

岡安 悟（日本原子力研究開発機構 先端基礎研究センター）

8. 雑誌及び国際会議等の刊行物、学会発表·················································· 111
8.1 加速器の運転状況及び開発··························································· 113
8.2 原子核構造········································································· 115
8.3 原子核反応········································································· 119
8.4 核化学 ············································································ 123
8.5 原子核理論········································································· 126
8.6 原子物理及び固体物理······························································· 133
8.7 材料の照射効果····································································· 134
9. 関連課室職員及び委員会································································ 137
9.1 課室職員··········································································· 139
9.2 委員会 ············································································ 143
10. 共同・協力研究及び施設供用リスト······················································ 145
10.1 共同・協力研究リスト······························································ 147
10.2 施設供用リスト···································································· 149

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JAEA-Review 2008-054

CHAPTER 1
Accelerator Operation and Development

1.1

Operation and usage of tandem accelerator and booster

1.2

KEK-JAEA Joint RNB Project

1.3

Impedance measurement of the bending magnet in the Tokai-Tandem high voltage terminal

1.4

Beam acceleration results of the new 14.5 GHz in-terminal ECR ion source

1.5

Study for installing a beam profile monitor in the high-voltage terminal

1.6

Performance test of low beta superconducting twin quarter wave resonator

1.7

Improvement of acceleration electric fields of superconducting booster resonators
using high pressure water jet rinse

1.8

Status of the JAEA-ISOL

1.9

Development of ion source for the JAEA-ISOL

1.10 Electrostatic collection method for identification of natural radon (222Rn)－ 1 －This is a blank page.

JAEA-Review 2008-054

1.1

Operation and usage of tandem accelerator and booster

M. Sataka 1, Y. Tsukihashi1, S. Hanashima1, S. Abe1, N. Ishizaki1, A. Osa1, M. Matsuda1, T. Nakanoya1,
H. Kabumoto1, N. Nakamura1, K. Kutsukake1, Y. Otokawa1, and T. Asozu1

The tandem accelerator and booster were operated for experiments from May 21, 2007 to July 10, 2007,
and from January 28, 2008 to May 15, 2008. The total operation time of the tandem accelerator for FY2007(from April 1, 2007 to March 31, 2008) was 105 days and 23 different beams were delivered forexperiments. The experimental proposals and the usage of the beam times for FY2007 are summarized intable 1 and table 2, respectively.
In FY2007, we had a maintenance period of 6 months for replacing the aged coil inside the 180 degree
bending magnet in the terminal. In this period, the 10 GHz in-terminal ECR ion source, NANOGAN, wasreplaced with the 14.5 GHz ECR ion source, SUPERNANOGAN. The beam-line components at theterminal were also realigned. This alignment greatly improved the transmission of ion beams through theterminal. As a result, we have achieved the acceleration of a 3μA proton beam and a 1.3 particle μA
fluorine beam.
Table 1. Experimental Proposals.
Research proposals accepted by the program advisory committee:
In-house staff proposals

6

Collaboration proposals

33

Number of experiment proposed

56

Total number of scientists participating in researchfrom out side239

in-house

269

Number of institutions presented

36

Table 2. Usage of beam-times in different research fields.
Research field

Beam time(days)(%)

Nuclear physics

42

40.0

Nuclear chemistry

11

10.5

Atomic and solid state physics

10

9.5

Radiation effects in materials

26

24.8

Accelerator development

16

15.2

total

1

Japan Atomic Energy Agency (JAEA)
－ 3 －

105

JAEA-Review 2008-054

Distributions of the terminal voltage and ion species for experiments are shown in fig. 1 and fig. 2,
respectively. Most of the beams were extracted from three negative ion sources, SNICS-2. The hydrogen
beam and multiply charged ion beams of nitrogen, oxygen and rare gases were accelerated from thein-terminal ECR ion sources. The ECR ion sources were used as much as 38 % of all the beam time.

Fig. 1 Distribution of terminal voltages.

Fig. 2 Distribution of beam species accelerated for experiments.
Dark and light color bars represent ion beams supplied by negative ion sources
and in-terminal ECR ion source, respectively.

－ 4 －JAEA-Review 2008-054

The super-conducting booster was operated for a total of 19 days to boost the energies of 7 different beams
from the tandem accelerator, as is summarized in table 3. These beams were used for experiments ofnuclear physics. Eight resonators out of 40 resonators had been treated by a high-pressure water jet sprayrinse (HPWR). Although the accelerating field gradients of these resonators were well recovered by HPWR,
there have been some decreases in those gradients one year after HPWR.
The 7Li and proton beams were supplied to the TRIAC (Tokai Radioactive Ion Accelerator Complex)
experiments for 9 days. The radioactivities of 8Li, 123In, and 143Ba were ionized and separated by ISOL andinjected into the TRIAC.

Table 3. Boosted ion beams for experiments.
Beam species

Boosted energies

Beam times (days)

(MeV)
18

O

180

3

S

345

1

Ni

205-245336
58(15 energy points)
64

Zn

82
86

344

3

Kr

380

3

Kr

395-4373(25 energy points)
98

Ru

430

－ 5 －

3

JAEA-Review 2008-054

1.2 KEK-JAEA Joint RNB Project
TRIAC Collaboration 1

The Tokai Radioactive Ion Accelerator Complex (TRIAC) is operating for nuclear physics and materials
science experiments at the JAEA-Tokai tandem accelerator facility under the collaboration between KEK
and JAEA (TRIAC collaboration). In FY2007, we developed medium-mass radioactive ion (RI) beams.
Radioisotopes of 123In and 143Ba, especially required in experimental proposals, were successfully
accelerated up to 178 keV/A. Their intensities at the secondary target were ~104 particles/sec. Produced by
the proton-induced fission reactions of natUCx, they were extracted and mass-separated as singly charged
ions by the isotope separator on-line (ISOL) of JAEA. They were charge-bred to higher charge states with acharge-to-mass ratios of about 1/7 by the charge-breeding electron cyclotron resonance ion source(CB-ECRIS) called as KEKCB. And then the charge-bred radioactive ions were accelerated by using aseries of heavy ion linacs, the split-coaxial radiofrequency quadrupole (SCRFQ) and the inter-digital H(IH) linacs. The acceleration of the radioactive ion beams charge-bred by CB-ECRIS was the first timeover the world.
The developments for acceleration of medium-mass radioactive ion beams were focused on improving the
CB efficiency (εCB) and the vacuum at the low-energy beam line for better transport efficiency. The εCB for
metallic elements increased from 0.1% to about 2% by tuning the injection of singly charged ions fromISOL to the KEKCB with double collimators. In the case of noble-gas element of Kr, we achieved that εCB
was larger than 8%. For the highly charged ions in flight along the low-energy beam line, high vacuum isnecessary to reduce their electron capture rates through the collisions with residual gases. To obtain highvacuum, we installed five cryopumps along the beam line. In a case of 129Xe19+, the escape fraction to lower
charge states reduced from 40% to 20%. The total transmission from ISOL to the secondary target
including εCB was about 2%, especially for gaseous RI.
Under a typical charge breeding condition of the KEKCB , we have observed background of several nAs in
the region of A/q of around 8 and between 6 and 7, presently and in future interested at TRIAC,
respectively (refer to fig. 1). It is a challenging problem in the development of the ECR charge breeder forradioactive ion beam facilities how to reduce the background components (dotted line in fig. 1) in the ion
spectrum, which would be an intolerable problem in experiments using the RI beams. We have tried toreduce such contaminations by careful selection of the inner-wall materials of the ECR plasma chamber. As
such an effort, we first identified the background ions by acceleration. Measuring their total energy, we canidentify their masses since their acceleration ends up with the same energy per nucleon. The backgroundions of a specific value of A/q were selected by the analyzing dipole magnet and the slits at the focal pointof the magnet. The mass resolving power of the magnet is about 100 with the horizontal slits of ±1 mm. For
the impurities at A/q = 7.68 which corresponds to 123In16+ requested for the β-NMR experiments at TRIAC,

1

Corresponding author, S.C. Jeong : High Energy Accelerator Research Organization (KEK)－ 6 －JAEA-Review 2008-054

we observed various heavy elements (light transition metals and Mo) with the intensity of 107

8

particles/s,

possibly originating from the inner-surface of the plasma chamber heavily contaminated in the fabrication.
Afterwards we changed the materials facing ECR plasma to aluminum (A1050 and A6030 in JapaneseIndustrial Standards). Before installing, we made clean their surface by a sand-blasting and high-pressure
distilled-water jet rinsing. As a result, the metallic elements almost disappeared and the intensity was
dramatically reduced to ~600 particles/s. The remaining impurities turned out to be Kr, which is naturally
abundant in residual gases inside KEKCB. When the A/q is defined more rigorously by horizontal slits, say±5 mm to ±1 mm, the reduction by more than a factor of 5 (almost one order of magnitude) is expected at
the expense of the reduction of what we want by a factor of 2. We also examined the region of A/q between
6 and 7, where background ions was about 1nA as shown in fig. 1. As an example, we looked at A/q of 6.45,
which was very close to 6.4 (32S5+) and 6.5 (13C2+) with the horizontal slits of ±1 mm. The background
intensity after acceleration was found to be several tens per second. It should be noted that the intensity ofbackground components measured at the focal plane of the analyzing magnet of the KEKCB was about
1 nA, regardless of the surface-cleaning: Most of them were removed not only by additional beam optics
fine-tuned to A/q of 6.45 in the beam transport line of TRIAC but also during acceleration.

Fig. 1 A/q distribution of ions at the focal plane of theanalyzing magnet of KEKCB. The A/q selections
introduced for further transport and acceleration are
indicated by arrows. Residual ion species very close to
the selections are also presented. The dotted line
representing continuous background ions is introduced
just for eye-guide.

The following experiments were carried out in FY2007 using the RI beams of 8Li, 123In, and 143Ba from
TRIAC: (1) Measurement of Li diffusion coefficients in Li ionic conductors (RNB07-J02). (2)Development of the spin-polarized beam with tilted foils for spectroscopic studies on nuclear structure(RNB07-K02, K03). (3) Search for the time reversal symmetry break by using spin polarized RI beams(RNB07-K04).
Some details of the experiments can be found elsewhere in this report.

－ 7 －JAEA-Review 2008-054

1.3 Impedance measurement of the bending magnet
in the Tokai-Tandem high voltage terminal
S. Hanashima 1

In the annual report of fiscal year 2006, we have reported about the impedance measurement [1]. In thisfiscal year, we started the design work of the power supply. On the other hand, the coil of the bending
magnet have been replaced to new one, as a part of overhaul processes of the magnet in its old age. The
new coil has somewhat different specifications against old one. So, we measured the impedance for the
new coil. The new measurement was made using an FFT (Fast Fourier Transform) analyzer.
The previous measurement for the old coil was made using a sine wave generator, a power amplifier and adigital storage oscilloscope. Measurements for several frequency points were treated one by one, so theprocess was very time consuming and it was difficult for us to view whole profile of the circuit in the datacollecting stage. After the measurements, we got a new tool, FFT analyzer. In a method using FFT analyzer,
the signal source was a pseudo random noise generator. The noise was fed to the coil through a power
amplifier. The coil current was converted to a voltage signal by a current probe. The FFT analyzer sensed
the voltage fed on the coil through channel number 1 and the current signal form the current probe throughchannel number 2, simultaneously. The admittance of the coil was analyzed as a transfer function from thecoil voltage to the coil current. A wide frequency range of the admittance data could be acquired in a run inthis method. In our measurements, range from 0.01Hz to 100kHz was covered by 3 frequency bands. The
acquired data were processed to suppress large noises and to reduce number of data points for lightening
the burden of later processing. Figure 1 shows the processed data, which have been used to design the
power supply. There is a clear resonance near 22kHz. We found an anomaly around that region in theprevious measurement, but the resonance was not realized at that time, because data points were sparse.
The amplitude of the admittance in the figure represents conversion factor from a voltage ripple to a current
ripple at a specified frequency. For example we are interested in harmonics of 400Hz, especially 1.2kHz,
because our power supply works on AC 400Hz 3-phase primary power. The graph shows that theadmittance at the 1.2kHz is about 7x10-3 ohm-1. It means that if ripple voltage at 1.2kHz is 1 volts,
associated ripple current is about 7x10-3 amperes (1V x 7x10-3 ohm-1).
In the design process of the power supply, the measured data are used. Figure 2 (a) shows a design example
for a power module of the supply. In the design, 4 identical power modules work parallel to establish
desired output power. Figure 2 (b) shows a simplified model of the power stage. The model of magnet coil
is connected to the output of the fig. 2 (b) to construct a simulation model from the duty cycle control of
pulse width modulation(PWM) to the magnet current. Figure 3 shows the results. In the calculation, themagnet model is given by a table, and a model of the power modules is set by mathematical formulas on a
spreadsheet. It must be noted that the result is not applicable directly to the frequency region above about
1

Japan Atomic Energy Agency (JAEA)－ 8 －JAEA-Review 2008-054

one 10th of PWM switching frequency. There is a sharp change of phase near 1.2kHz, caused by a second
order low pass filter for the PWM output. It is desired to shift the frequency to reduce ripple, because thefrequency is very close as the third harmonics of the primary AC supply.
We must add a current sensor and an error amplifier working as a loop filter to the model to close a
feedback loop. The loop filter must fulfill both terms for stability of feedback loop and terms forsuppressing disturbances in a level desired as the power supply for the bending magnet. The information
about the impedance of the magnet eases the design process.
1E+1

Amplitude(1/Ω)

1E+1|Y|(1/Ω)

1E-1

1E-3

Admittance

Ref

1E-1

1E+1

1E+3

1E-7
1E-3

1E+5

Frequency(Hz)

1E+3

1E+5

90.
Phase

Phase

1E+1

180.

Phase Ref

90.
0.
-90.
-180.
1E-3

1E-1

Frequency(Hz)

180.
Phase

1E-3
1E-5

1E-5
1E-3

1E-1

0.
-90.

1E-1
1E+1
1E+3
Frequency(Hz)

-180.
1E-3

1E+5

Fig. 1 Admittance of BM TL-1. Arranged to use
power supply design from raw data obtained by
the FFT analyzer. Characteristic of a series circuitof 0.2Ω resister and 0.6H inductance is also shownfor comparison.
0.27Ω
400V
from PFC

1E-1
1E+1
1E+3
Frequency(Hz)Fig. 3 Simulated transfer function from PWM
control to current output.
Note that 180º is associated to -180º.

8mΩ
50μH,5mΩ

Ein*≒40V

×

*
10mΩ

d : duty cycle

Output12.5μH

Output

td

36:7
5mΩ

1E+5

1.25mΩ
1000μF

260μF,5mΩ

(a)

(b)

Fig. 2 Example circuit of power module for the power supply and simplified simulation model.

Reference[1] S. Hanashima, JAEA-Tokai TANDEM Ann. Rep. 2006, JAEA-Review 2007-046 (2008) 6.

－ 9 －JAEA-Review 2008-054

1. 4 Beam acceleration results of the new 14.5 GHz in-terminal ECR ion source
M. Matsuda 1, T. Asozu1, T. Nakanoya1, Y. Otokawa1, K. Kutsukake1, and S. Hanashima1

In-terminal ECR ion source [1] was upgraded by employing a high performance all-permanent-magnet type
14.5GHz ECR ion source SUPERNANOGAN in place of a compact 10GHz ECR ion source during a long
maintenance period in FY2007. The arrangement of the new ion source is shown in fig. 1. For this upgrade,an extractor electrode and an einzel lens were replaced to the optimized ones.

Fig. 1 Cross section of the new 14.5GHz in-terminal ECR ion source with electrode. The solid
curve corresponds to the axial magnetic field distribution.
The RF system of the ion source was replaced because of the frequency change to 14.5 GHz. A travelingwave tube (TWT) module with 200W output is used as the main amplifier and its power consumption is
only 800W. To protect it from compressed insulation gas and electric surges from a high voltage discharge,
TWT, DC power supply, oscillator, and attenuator for the output control were put into the pressure-resistantcontainer which kept the inside at 1 atm. regrettably, RF output power was limited to 16 W due to a troubleof the circulator at the amplifier output.
For an ECR ion source composed of powerful permanent magnets, the influence of leakage magnetic fields
on an ion beam can not be ignored. We measured magnetic field on a vertical beam line in the terminal andfound a maximum field of 2mT. This much leakage makes beam acceleration difficult because it bends abeam far beyond a tolerance of about 2mm. Especially, in the beam acceleration from the negative ion
source, this is an important problem because it is not possible for our concerned beam handling system tocorrect such a steered beam orbit. In a simple calculation for the case of accelerating a hydrogen beam from1

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JAEA-Review 2008-054

the negative ion source at the terminal voltage of 15MV, the beam orbit is steered by about 25mm at theentrance of 180 degree bending magnet. Therefore, we made a new shield panel which covered up the ion
source and its extraction and focus chamber with 3.2mm thick iron plates. With the iron shield, the leakage
magnetic field was suppressed to about 1/50 and there was no beam steering problem in actual accelerationof negative ion beams after the upgrade.
Highly charged krypton and xenon ions were accelerated from the tandem accelerator. The intensities ofthese ions are shown in fig. 2. The beam handling from the new ion source was easily done in the same way
as the old 10GHz in-terminal ECR ion source. The extracted ion beam was stable and the beamtransmission efficiency was nearly 100% for acceleration from the terminal to the tandem exit. The
intensities were increased 3-5 times as much as those before. Xenon ion energy reached 375MeV which is
the highest energy this tandem ever had.
The highly charged ion intensities which were generated by an RF output of 16W agreed with the result ofour bench test. We, therefore, expect that beam intensities will be increased ten times by fixing RF
amplifier system.

Fig 2. Charge state distributions of Kr and Xe ions from 14.5GHz in-terminal ECR ion source.
Beam intensities were measured at exit of accelerator.

References[1] M. Matsuda et al., JAEA-Tokai TANDEM Ann. Rep. 2005, JAEA-Review 2006-029 (2006) 14-15.
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JAEA-Review 2008-054

1. 5

Study for installing a beam profile monitor in the high-voltage terminal
T. Asozu 1 and M. Matsuda1

Many control devices are installed in the high voltage terminal of the JAEA-Tokai tandem accelerator. In
the terminal, ion beams are bent 180°by a bending magnet (BM) and focused at the entrance of the highenergy acceleration tube by three electrostatic quadrupole triplet lenses (EQ) as shown in fig. 1. The beam
optics has a high degree of freedom so that it needs precise control in the terminal. Then we planned to
install a beam profile monitor (BPM) to monitor the beam profile at the last waist point in the terminal. The
BPM has a wire which turns and crosses a beam in two (x and y) directions during a turn so that secondary
electrons from the wire can be collected to produce a signal in a series of x and y beam profiles (see fig. 4).
And we can see spreading widths and center positions of a beam on a display. Figure 1 also shows thelocation where the BPM will be installed.

BPM

Fig. 1 Calculated beam envelope and the location of the terminal BPM.
The BPM must be insulated electrically from outside of the high voltage terminal. Then we designed aterminal BPM system using fiber-optic modules as shown in fig. 2. We receive BPM signal throughfiber-optic modules and control the gain of the signal by the BPM controller and CAMAC system. For
accelerator operation, the BPM signal should be sent and received quickly in real time. Then we use
fiber-optic modules for transmitting BPM instead of using an existing CAMAC system. We use a plastic
optical fiber of which insulation quality has been established well in transmitting signals from CCD camera
looking at an electron-stripping carbon foil in the terminal.
The fiber-optic modules were checked, and the linearity and frequency response were observed (see fig. 3).
Though the linearity was limited by an output voltage of 5V, we could control the gain of BPM signals with
the BPM controller.
The frequency components of BPM signal spread over a range of about 30~10k Hz and the frequency
response covered the range as is seen from the curve in fig. 3. These modules were also tested with signals
from BPM I1-1 which was actually monitoring an ion beam, and we found out the beam profiles shown in
1

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JAEA-Review 2008-054

fig. 4. Comparing two profiles of a raw signal from the BPM and a signal transmitted through thefiber-optic modules, the latter one shows distorted profiles. The distortion was caused by AC coupling
between the two fiber-optic modules. The distortion is not so serious for our purpose to manipulate thebeam, because we concentrate our attention to the beam spreading width and center position. As a result, it
was found that the fiber-optic modules were useful to send and receive BPM signals.

Fig. 2 Control block diagram for the terminal BPM system.

Fig. 3 Linearity (left) and frequency response (right) of the fiber-optic modules.

0.5V

5ms

1V

5ms

Fig. 4 BPM signals. Raw (left) and using fiber-optic modules (right).

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JAEA-Review 2008-054

1. 6 Performance test of low beta superconducting twin quarter wave resonator
H. Kabumoto 1, S. Takeuchi1, N. Ishizaki1, M. Matsuda1, and Y. Otokawa1

We started development of superconducting twin quarter wave resonator (Twin-QWR) for the purpose ofacceleration of low velocity heavy ions (βopt=0.06) in FY2004, and fabricated a prototype Twin-QWR in
FY2005. We carried out off-line performance test in FY2006, and confirmed the performance of that thequality factor (Q0) was 2×108 at 4.2 K at low electric field, the acceleration electric field (Eacc) was 2.9
MV/m at RF power input of 4.0 W.
Figure 1 shows a cutaway drawing of Twin-QWR. We
disassembled Twin-QWR because it was thought that theconnection between top end plate and outer conductor was
insufficient. Figure 2 shows the main parts of Twin-QWR. It
consists of inner conductors made of pure-Nb and outerconductor made of Nb-Cu composite plate. The innerconductor part and outer conductor are connected by asuperconducting Nb-gasket. We found that the Nb-gasket wasdislocated by 0.4mm and not completely connected to outerconductor. We made the holder of Nb-gasket for the purposeof preventing dislocation, and assembled Twin-QWR again.
Figure 3 shows the resonator Q0-values at 4.2 K before andafterchangingtheNb-gasket.

The

performanceof

8

Twin-QWR was improved to Q0= 9×10 at low electricfield, and Eacc=5.8 MV/m at RF power input of 4.0 W. The
Q0-values degraded slightly around Eacc=6.0 MV/m, and theFig. 1 Cutaway drawing of Twin-QWR.
Inner conductor

Outer conductor
Nb gasket

thermal breakdown was observed at Eacc=6.5 MV/m.
Figure 4 shows the frequency shift as a function of heliumpressure. This frequency instability happens because of thedeformation of the top end plate by the helium pressure.
This effect of Twin-QWR is bigger than that of QWR,
because Twin-QWR has two inner conductors that affectthe change of electric capacitance by deformation of the top
end plate sensitively. The frequency shift of Twin-QWR
was about 0.71 kHz/(kgf/cm2), and it was about 2.6 times aslarge as QWR’s 0.27 kHz/(kgf/cm2).

Assembled Twin-QWR

Fig. 2 Main parts and assembled Twin-QWR.
1Japan Atomic Energy Agency (JAEA)－ 14 －

JAEA-Review 2008-054

1.0E+09

0.44W

after
before

1.4W

Quality factor Q₀

4.0W→ 5.8MV/m @ 4W
0.5W
1.4W

1.0E+08

10.6W
4.1W

11.0W
32.8W

↓
2.9MV/m @ 4W
1.0E+07
0

1

2

3

4

5

6

7

8

9

10

Acceleration electric field Eacc [MV/m]
Fig. 3 Resonator Q0-values at 4.2K before and after changing Nb-gasket.

Frequency shift ⊿f₀ [kHz]0.4
Twin-QWR
QWR
0.3⊿ｆ=0.71×⊿P
0.2

0.1⊿ｆ=0.27×⊿P
0.0
0.0

0.1

0.2

0.3

0.4

0.5

0.6

2

Helium pressure ⊿P [kgf/cm ]Fig. 4 Frequency shift of Twin-QWR and QWR as a function of helium pressure.

References[1] H. Kabumoto et al., JAEA-Tokai TANDEM Ann. Rep. 2006, JAEA-Review 2007-046 (2008) 13-14.
[2] H. Kabumoto et al., JAEA-Tokai TANDEM Ann. Rep. 2005, JAEA-Review 2006-029 (2006) 12-13.
[3] H. Kabumoto et al., JAERI TANDEM Ann. Rep. 2003, JAERI-Review 2004-027 (2004) 13-14.

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JAEA-Review 2008-054

1. 7 Improvement of acceleration electric fields of superconducting booster resonators
using high pressure water jet rinse
H. Kabumoto 1, S. Takeuchi1, N. Ishizaki1, T. Yoshida 2, T. Ishiguro2, and K. Yamaguchi2

We curried out a high-pressure water jet rinse (HPWR) to on-line superconducting resonators (L37-L40) in
FY2006, and it was confirmed that HPWR was effective for improvement of acceleration electric field. We
carried out HPWR to other 8 resonators in FY2007 (L25-28 and L33-36). Our HPWR procedure is asfollows. First, we rinse the resonators using methanol for the purpose of washing contaminations, likeindium particles, oil and other chemical pollutions. Then, we do HPWR for two hours using waterpressurized to 6-8MPa. We use the CO2-melted water for the purpose of preventing anodizing the niobium
surface. After HPWR, we rinse the resonators using methanol again for the purpose of early drying. Finally,
we carry out mild baking at 120℃ for 2days at a pressure of ultra high vacuum.
Figure 1 shows the change of acceleration electric fields (Eacc) at RF power input of 4.0 W before and after
HPWR. The Eacc of 8 resonators (L25-28 and L33-36) were improved after HPWR, and the average of Eacc
at RF power of 4.0 W of 8 resonators was improved from 4.96 MV/m to 6.53 MV/m. We have measured
the acceleration electric fields of L37-L40 resonators after one year from HPWR. The average of Eacc at RF
power of 4.0 W was reduced from 5.91 MV/m to 4.94 MV/m.

Eacc at RF power of 4.0 W [MV/m]

10

beforeafter
one year after

8
6
4
2
0
25

26

27

28

33

34

35

36

37

38

39

40

Resonator No.

Fig. 1 Eacc at RF power input of 4.0 W before and after the HPWR.
References[1] H. Kabumoto et al., JAEA-Tokai TANDEM ANN. Rep. 2006, JAEA-Review 2007-046 (2008) 15-16.
1
2

Japan Atomic Energy Agency (JAEA)
Atox Co., Ltd.
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JAEA-Review 2008-054

1. 8Status of the JAEA-ISOL

Y. Otokawa1, A. Osa 1, T.K. Sato1, Y. Fuchi2, and S. Ichikawa1

In the FY2007, the isotope separator connected on line to the JAEA-Tokai tandem accelerator(JAEA-ISOL) was operated 18 days to deliver radioactive nuclear beams (RNB) for experimental research
programs. It was also operated 19 days for an ion-source development and to optimize the use of apparatus
connected to the JAEA-ISOL.
We served RNB for experiments using two kinds of ion sources: a surface ionization-type ion source (SIS)
and a forced electron beam induced arc discharge (FEBIAD) type one. A uranium-carbide target whichused to produce neutron-rich nuclei in the proton-induced fission of 238U, and thin metal-foil target for
production of neutron-deficit nuclei in the nuclear fusion and nucleon transfer reactions, respectively, areavailable in both ion sources. Alkali, alkaline-earth and rare earth elements are effectively ionized by SIS
and many volatile elements are ionized by FEBIAD type ion source. Provided RNB to the experiments are
summarized in table 1.
As shown in table 1, we were successful in providing neutron-rich nuclei produced in proton-induced
fission of 238U, 123In and 143Ba, for acceleration with Tokai Radioactive Ion Accelerator Complex (TRIAC).
Beam intensities including the 8Li provided to TRIAC are shown in table 2. These intense beams wereachieved by increase in the primary beam from the tandem accelerator which was progressed with precise
realignment of beam optical devices. We confirmed that the neutron-rich RNB intensity was proportional tothe primary beam one and both integrated-target-ion sources were steadily worked under experimental
condition.
The acceleration of two neutron-rich RNB, 123In and 143Ba, with TRIAC were successfully performed forthe first time. However, concerning experimental research program with TRIAC, tenfold and/or
hundredfold intense RNB are required. For enhancement of the beam intensity, we have been developed
FEBIAD-E type ion source which works at high temperature up to 2300K, and study of the configurationof the base material of the uranium-target to make short release time of fission products is under progress[1].
On the other hand, experiments scheduled at the irradiation room, where the JAEA-ISOL is installed in,becomes so tight and the residual radiation dose level has been so high. We have to think a safer procedure
to exchange irradiated ion source at every experiments.

1
2

Japan Atomic Energy Agency (JAEA)
High Energy Accelerator Research Organization (KEK)－ 17 －

JAEA-Review 2008-054

Table 1. Radioactive nuclear beams delivered to experiments using the JAEA-ISOL.
Date

RNB

Reaction

28-29,May, 2007

94

238

5-6,May, 200794

Y etc.

238

11-14,Jun,2007

8

Li

13

7

13, Feb., 2008

21

12

12

18-20, Feb., 2008

94

238

10-12,Mar., 2008

123

238

25, Mar., 200892

26-27,Mar., 2008143

Y etc.

U(p,f)
U(p,f)
8

C( Li, Li)

Ion source1)

Primary beam

Research program

U-SIS

1

H+/30 MeV

Decay spectroscopy

U-SIS

1

H+/30 MeV

Decay spectroscopy

F-SIS

7

3+

Development of TRIAC,

F-SIS

12

5+

C /90 MeV

Development of RF linear-trap

U-SIS

1

H+/30 MeV

Decay spectroscopy

U-FEBIAD

1

H+/30 MeV

Experiment use in TRIAC

U-SIS

1

H+/30 MeV

Development of RF linear-trap

U-SIS

1

Experiment use in TRIAC

Li /60 MeV

Experiment use in TRIAC

1)Na

C( C,p2n)

Y etc.

U(p,f)

In

Rb,
Ba

U(p,f)

142

Cs

238

U(p,f)

238

U(p,f)

H+/30 MeV

uranium-carbide target attached to the ion source indicated by U-SIS, U-FEBIAD and thin metal foil target
attached to the ion source indicated by F-SIS, F-FEBIAD, respectively.

Table 2. Beam intensity of 8Li, 123In and 143Ba providing to TRIAC.
RNBIntensity

Ion source

Primary beam fromTandem accelerator

8Li

1.0x105 pps

F-SIS

7

123

In

1.0x106 pps

U-FEBIAD

1

143

Ba

1.4x106 pps

U-SIS

1

Li3+/60 MeV/83 pnA
H+/30 MeV/680 nA
H+/30 MeV/1000 nA

References[1] A.Osa et al., JAEA-Tokai TANDEM Ann. Rep. 2006, JAEA-Review 2007-046 (2007) 18.

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JAEA-Review 2008-054

1. 9 Development of ion source for the JAEA-ISOL
A. Osa 1, Y. Otokawa1, T.K. Sato1, and S. Ichikawa1

For the purpose of perturbed angular correlation measurements in solid state physics, we developed a metal
foil target for the JAEA-ISOL to produce a radioactivity of 111In (T1/2=2.8047d). We are required to implant
111

In into sample in the dose of 1011~1012 particles/sample. It corresponds to the intensity of several 105 pps

and the irradiation time of 1 day. With this beam intensity and the long half-life of 111In, the increase of111

In radioactivity is only a few Bq/s, so that the method of radiation measurements is not useful for the

beam handling. Therefore, we planed to produce short-lived isobars in heavy ion reactions, 111Sb(T1/2=1.25m) and 111Sn (T1/2=35.3m), in addition to the 111In and separate them at the same time for theconvenience of the beam handling.
The FEBIAD ion source is used for the ionization of indium, tin and antimony. A high-melting metal target,
such as 41Nb, 42Mo and 45Rh, has to be used because the FEBIAD ion source for the heavy ion reactions is
operated at a high temperature (about 1550 oC). A schematic view of the FEBIAD ion source is shown infig. 1. A natMo target with a thickness of 3 μm was previously irradiated by 19F ion beam to produce A=111
isobar. In this reaction, the intensity of 111In beam was several 104 pps with the primary beam intensity of
100 p-nA. It is estimated that 96Mo+19F→115Sb* is a major reaction to produce 111Sb and 111Sn. From thefact that natural abundance of 96Mo isotope is 16.68%, it is expected that the sixfold intensity of 111In beam
when we use isotopically-enriched 96Mo target.

Anode

CathodePlasmaRadioactive
ion beam
Catcher
TargetEntrance window

Primary beam fromtandem accelerator

Fig. 1 Schematic view of the FEBIAD ion source.
1

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JAEA-Review 2008-054

The enriched 96Mo target is costly to prepare so that we made a comparison experiment of bombarding 12C
to the naturally mono-isotopic 103Rh target; this reaction produces the same compound nucleus 115Sb*. The
intensity of 111In beam was 1.1x105 pps with the primary beam intensity of 100 p-nA. However, the beam
intensity was obviously decreasing as time went on. We found that Rh made a binary metallic alloy [1]with Ta, which was a structural material of the ion source, and melted in a few hours at the ion-source
operational temperature.
We estimate to provide A=111 isobars beam with the intensities of several 105 pps. To satisfy the demands
of users, we will proceed to investigate the intensities of A=111 isobars by improving endurance of theenriched 96Mo target foil and the Ta foil for the primary beam entrance window, as well as anothercomparison experiment with a naturally mono-isotopic 93Nb target and a 22Ne beam.

Reference[1] H. Baker, Editor, ASM Handbook. Vol. 3: Alloy Phase Diagrams, ASM International, New York (1992).

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JAEA-Review 2008-054

1.10 Electrostatic collection method for identification ofnatural radon (222Rn)
M. Nakamura 1, M. Matsuda1, T. Ishii1, N. Ishizaki1, A. Osa1, T. Nakanoya1, H. Kabumoto1,
K. Kutsukake1, Y. Otokawa1, T. Asozu1, M. Asai1, and T. Ohkura1

On an occasion of surveying contamination all over floors, alpha rays (0.06Bq/cm2) were detected on thefirst basement passage of the Tandem Accelerator Facility. We attempted to identify the alpha-emitting
nuclide in parallel with conducting more surveys in this area. In the survey, we found a crack of concrete at
the spot where alpha rays were detected. We identified all nuclides emitting gamma rays at the crack as
Naturally Occurring Radioactive Materials, (NORM: 40K, 214Bi, 228Ac and so on) by in-situ gamma-ray
measurement. Therefore, we inferred that radon seeped out of the crack.
Radon is not easy to be collected and detected because of its nature of noble gas. There have been several
methods to measure natural radon in the atmosphere. One of them is the double filtering [1]: after
separation of all radioactive gases except for radon at the first filter, radon is collected at the second filter.
This method needs a long time (from hours to days) and large amount of sampling gas to measure. Anotherone is the electrode collection [2]: positively charged alpha-decay products of radon, for example 218Po arecollected at a negatively charged electrode. The concentration of radon is estimated by measuring its
radioactivity. This measurement can be completed in several minutes because a half-life of 218Po (3.05min)is fairly shorter than that of radon (3.8days). We needed to confirm promptly that radon seeped out of thecrack, but not to measure the concentration (nor its time variation). And we were unprepared to carry out
either of those methods which required a large apparatus connected to a power source. Therefore, weapplied a new method which was speedier and handier than those methods.
We have developed an electrostatic collection method: after collection of 218Po using a negatively charged
Teflon sheet in place of the electrode collection, we measured alpha rays and gamma rays from this sheet.
We identified decay products of radon (218Po, 214Pb and 214Bi) with this collection method. Figure 1 shows
the decay-curve of alpha rays which were measured by putting alpha-ray survey meter and the sheet face toface. The analyzed half-life was 3.45±0.45min; it indicated that purely 218Po was collected on the sheet.
Figure 2 shows that of gamma rays which were measured by putting the sheet in front of Ge detector
several minutes after collected 218Po have decayed. They were insulated by the lead shield to decrease
background radiations. The analyzed half-life (25.6±4.7min) was coincident with that of 214Pb. From theseresults, we have identified radon seeping out of the crack.
Our developed collection method has several advantages over the previous methods. First of all, thismethod is more convenient. All you need are alpha-ray survey meter and one sheet which gets easily
negatively charged electrostatically, for example Teflon or polyvinyl chloride. Secondly, advanced
1

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JAEA-Review 2008-054

measurements can be carried out, for example a half-life measurement because concentrated 218Po on the
sheet dose not diffuse quickly. After collection, you can identify 222Rn immediately. Third, with portabilityof the collection sheet (we used a Teflon sheet: 5cm wide, 15cm long and 3mm thick), the sheet can be
carried in low background environment to measure gamma rays more sensitively.

Fig. 1 Alpha-ray counts as a function oftime with electrostatic collection method.
The solid line is a fit with a single decay
curve.

Fig. 2 Gamma-ray counts of 214Pb 351keV as
a function of time measured after collection of
218
Po on Teflon sheet. The solid curve is a fit
with a single decay curve, inclusive of
background.

References[1] Thomas J.W. and LeClare P.C., Health Physics, 18 (1970) 113-122.
[2] G. Dalu and G.A. Dalu, Aerosol Science, Vol.2 (1971) 247-255.

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JAEA-Review 2008-054

CHAPTER 2
Nuclear Structure

2.1

Study of high-spin states in 36S and 36Cl

2.2

Spectroscopy of 38Cl

2.3

Study of low-lying collective modes in 100Ru by multiple Coulomb excitation

2.4

In-beam gamma spectroscopy of 168Ta

2.5

Isomers in neutron-rich tantalum isotopes

2.6

Prolate and oblate shape co-existence in 188Pt

2.7

Gamma-rays in ground-state band of 246Pu

2.8

Quasi-particle states in 249Cm measured by in-beam γ-ray spectroscopy

2.9

Alpha-gamma coincidence spectroscopy of 259No

2.10 Decay study on fission products with on-line isotope separator
2.11 A gas cell for on-line laser spectroscopy of radioactive isotopes of refractory elements
2.12 On-line test of RI ion trap system
2.13 Development of spin-polarized radioactive nuclei around 132Sn for nuclear spectroscopy－ 23 －

This is a blank page.

JAEA-Review 2008-054

2. 1

Study of high-spin states in 36S and 36Cl

E. Ideguchi 1, T. Morikawa 2, M.L. Liu1, Y. Toh 3, M. Koizumi3, A. Kimura3, H. Kusakari 4, M. Oshima3,
B. Cederwall 5, K. Furutaka3, Y. Hatsukawa3, S. Mitarai2, M. Sugawara 6, and Y. Zheng1

High-spin level structures of A ≈ 30 nuclei have been receiving increased attention in recent years [1,2]. In
this region several interesting phenomena can be investigated such as violation of mirror symmetry, cluster
structure, shape coexistence, and the interplay between single-particle and collective motion [1,2]. Amongthem 36S is known as a puzzling nucleus, where several microscopic models such as configuration mixing
and the shell model are unable to reproduce the B(E2;21+→01+) value and inelastic proton scattering
angular distribution [3,4]. The study of the high-spin level structures in 36S and its neighboring nuclei will
give a testing ground to the models and will help for solving the problem. In this report, experimental
studies on high-spin states in 36S and its neighboring nucleus 36Cl were presented.
An in-beam γ-ray spectroscopy was employed to study high-spin states of 36S and 36Cl via a 18O + 24Mg
fusion-evaporation reaction. The 18O beam of 70 MeV was provided by the tandem accelerator of the Japan
Atomic Energy Agency. A target of an isotopically enriched 24Mg foil of 1 mg/cm2 thickness with 8 mg/cm2
nat

Pb backing was used. Fourteen HPGe detectors with BGO anti-Compton shields from the GEMINI-II

array [5] were used to detect γ rays in coincidence with a charged particle filter, Si-Ball [6]. The HPGe
detectors were placed at 6 different angles, namely 47º (4 Ge's), 72º (2 Ge's), 90º (2 Ge's), 105º (4 Ge's),
144º (1 Ge) and 147º (1 Ge) with respect to the beam direction, which enables to perform angular
distribution and DCO analyses. The Si-Ball consists of 20 ΔE Si detectors [6] surrounding the target.
Events were collected when at least two HPGe detectors and one Si detector were fired in coincidence.
Based on the γ-γ coincidence relations, γ-ray energy sum, and intensity balances of the transitions,previously reported level scheme for 36S [7] was confirmed up to the 6.69 MeV level. In the present study,
new γ-ray peaks at 1182, 1315 and 2218 keV were identified in coincidence with a 3291 keV transition asshown in fig. 1. The results of the DCO analysis suggest stretched quadrupole character for the 1182 and2218 keV transitions and dipole character for the 1315keV transition. In 36Cl, high-spin levels up to (7)+state at 5.313 MeV were previously assigned. On top of the (7)+ state a 466 keV transition was tentatively
placed and it was reported to be in coincidence with 1019 and 2795 keV transitions from (7)+ to (6+) andfrom (7)+ to 5- levels, respectively [8]. Figure 2 shows the γ-ray energy spectrum by gating on a 466 keVtransition and it was found that 1019 and 2795 keV peaks did not appear in the spectrum. Consequently, the466 keV transition was assigned as de-exciting from the (7)+ state in parallel with 1019 and 2795 keVtransitions. After the γ-γ coincidence analysis of 36Cl data, 16 γ-ray peaks were newly identified. Data
analysis is in progress.
1

CNS, University of Tokyo
Kyushu University
3
Japan Atomic Energy Agency (JAEA)
4
Chiba University
5
Royal Institute of Technology
6
Chiba Institute of Technology
2－ 25 －

JAEA-Review 2008-054

Fig. 1 γ-ray spectrum by gating on 3291 keV transition between 21+ and 01+ level in 36S.

Fig. 2 γ-ray spectrum by gating on 466 keV transition in 36Cl.

References[1] P. Mason et al., Phys. Rev., C71 (2005) 014316/1-8.
[2] F. Della Vedova et al., Phys. Rev., C75 (2007) 034317/1-7, and references there in.
[3] F. Maréchal et al., Phys. Rev., C60 (1999) 034615/1-12.
[4] E. Khan et al., Nucl. Phys., A694 (2001) 103-131.
[5] M. Oshima et al., J. Radioanal. Nucl. Chem., (2008) to be published.
[6] T. Kuroyanagi et al., Nucl. Instrum. Methods Phys. Res., A316 (1992) 289-296.
[7] X. Liang et al., Phys. Rev., C66 (2002) 014302/1-4.
[8] E.K. Warburton et al., Phys. Rev., C14 (1976) 996-1009.

－ 26 －

JAEA-Review 2008-054

2. 2

Spectroscopy of 38Cl

T. Morikawa 1, E. Ideguchi 2, M.L. Liu2, Y. Zheng2, M. Oshima 3, M. Koizumi3, Y. Toh3,
A. Kimura3, A. Osa3, H. Harada3, K. Furutaka3, S. Nakamura3, F. Kitatani3,
Y. Hatsukawa3, M. Sugawara 4, H. Kusakari 5, and S. Mitarai1

Motivated by the recent discovery of an island of inversion [1], a systematic investigation of high-spinstates in nuclei in neutron-rich A = 30 ~ 40 region has been underway as a cooperative study at the JAEA
tandem accelerator facility. Since the evolution of shell structure is a function of nuclear deformation androtation as well as isospin, systematic understanding of high-spin levels in nuclei in the neutron-rich region
is of great interest. Identification and study of the levels involving the {sd} to {fp} cross-shell excitation
would be a key to clarify the evolution of N = 20 neutron shell gap.
The excited levels in 38Cl have been investigated by using an 18O + 26Mg reaction at 3.72 and 5.00 MeV/u.
The 18O beams delivered from the JAEA tandem accelerator were incident on the 4 mg/cm2 thick 26Mg
target. γ-rays were detected with the GEMINI-II Ge detector array [2]. The VME-CAMAC based dataacquisition system was triggered by the γγ two-fold events within a 1 μsec coincidence window. Data werestored on the HDD storage of a UNIX PC and were off-line sorted into γγ correlation matrices for thedetailed analysis. A γ-ray spectrum gated by transitions in 38Cl is presented in fig. 1. Based on the γγ
coincidence relations, γ-ray energy sum and intensity balance, the level scheme of 38Cl has been extended
up to the Jπ = (8+) state at 4836 keV. As the result, 38Cl has turned to be the heaviest chlorine isotope of
which the high-spin states are identified. Spin assignments of the new levels were tentatively made byusing the coincidence relation and the observed γ-ray anisotropy with respect to the beam direction. Basedon the consideration that the heavy-ion induced fusion reaction predominantly populates the yrast levels
while the maximal spin for the π{0d3/2}1⊗ν{0f7/2}1 configuration is J = 5, the assignment of the negative
parity for the states of J > 5 may be unlikely.
For the comparison with the nuclear theory, shell model calculations were performed in the {1s1/2,0d3/2,
0f7/2,1p3/2} model space by using the jj-coupled shell model code jjSMQ [3] with the surface deltainteraction (SDI) as presented in fig. 2. The two-body matrix elements were calculated with the strengthparameters A0 = 0.90 and A1 = 0.56, which are known to give a very good reproduction of the levelstructure of 43Sc by using the 0d3/2-0f7/2 shell gap of 4.9 MeV [4]. In the present case for the 38Cl nucleus,
however, the positive parity levels, i.e. Jπ = (6+) at 3645 keV, Jπ = (7+) at 3816 keV, and Jπ = (8+ ) at 4836
keV, were found to be better reproduced with a smaller gap of 3.9 MeV. Since the similar trend is also seen
in a 33P nucleus [5], it might suggest a possible onset of the shell gap reduction in this region. The analysis
is still in progress.
1

Kyushu University
CNS, University of Tokyo
3
Japan Atomic Energy Agency (JAEA)
4
Chiba Institute of Technology
5
Chiba University
2－ 27 －

JAEA-Review 2008-054

171
292

700

Cl

Gate: 171keV + 292keV + 1191keV

500

554

2044

200

1021
1030
1191

300

2681

638

400

755

Counts/Channel

600

38

100
0
0

500

1000
1500
2000
Channel Number (keV)

2500

Fig. 1 γ-ray spectrum gated by the transitions in 38Cl.

Excitation Energy (MeV)5432EXP - Yrast
EXP - Yrare
SDI - Yrast
SDI - Yrare
EXP + Yrast
SDI + Yrast

1
0

0

1

2

3

4
5
SPIN (J)

6

7

8

9

Fig. 2 A plot of 38Cl levels in comparison with the shell model calculations using SDI.
In the calculations, the gap energy between 0d3/2 and 0f7/2 single particle levels waschosen to be 3.9 MeV for better reproduction of positive parity yrast levels.

References[1] T. Motobayashi et al., Phys. Lett., B346 (1995) 9-14, and references therein.
[2] K. Furuno et al., Nucl. Instrum. Methods Phys. Res., A421 (1999) 211-226.
[3] K. Takada et al., code available at ftp.kutl.kyushu-u.ac.jp:/pub/takada/jjSMQ/ (accessed 2008-05-30).
[4] T. Morikawa et al., Phys. Rev., C70 (2004) 054323/1-7.
[5] T. Morikawa et al., Kyushu University Tandem Accelerator Laboratory Report Vol.10 (2007) 56-58.
－ 28 －

JAEA-Review 2008-054

2. 3

Study of low-lying collective modes in 100Ru
by multiple Coulomb excitation

Y. Toh 1, M. Koizumi1, M. Oshima1, A. Kimura1, H. Harada1, K. Furutaka1, F. Kitatani1, S. Nakamura1,
Y. Hatsukawa1, A. Osa1, M. Sugawara2, and T. Morikawa3

Shape transitions of ground states can occur with the variation of neutron numbers in Ru isotopes. In fact
the spherical shape for 98Ru and deformed for 108Ru are reported in theoretical studies[1,2]. Recently,
Iachello has introduced an analytic treatment of critical shape transition point solutions with developmentof the new class of symmetries which are based on the solutions to different equation[3,4]. A dynamical
symmetry called E(5) applies to nuclei undergoing transitions from spherical to γ-unstable shapes.
Ruthenium isotopes are proposed to lie at this phase-transition point. Multiple Coulomb excitation is a
useful method to deduce electromagnetic properties, which reflect shapes of nuclei, without taking into
account the effects of nuclear interactions [5,6]. Therefore the low-lying excited states in 100Ru werestudied by Coulomb excitation experiment.
A 440 MeV 100Ru beam was excited on a 208Pb target with approximately 2 mg/cm2 thickness. A γ-ray
detector array, GEMINI-II (upgraded version of GEMINI [7]), consisting of 16 Ge detectors with BGOCompton suppression shields, was used to detect deexcitation γ rays. The Ge detectors were placed at θ =47˚, 72˚, 90˚, 105˚, 147˚, and 144˚ relative to the incident beam. The scattered particles are detected with aposition-sensitive particle detector system [8] with four plastic scintillators each of which is coupled to a
position-sensitive photomultiplier tube. It covered approximately 30% of the total solid angle, ranging from21+ Æ 01+
02+ Æ 21+41+ Æ 21+31− Æ 22+23+ Æ 02+22+ Æ 21+

Counts

103

−

2

+

02 Æ 2 1++

31 Æ 4 1

1022+ Æ 01++23 Æ 21+23+ Æ 01+31− Æ 21+61+ Æ 41+

1

10

100
500

1000

1500

Energy (keV)
Fig. 1 An example of Doppler-shift corrected spectra. Thirteen peaks were identified as
the γ rays of 100Ru.
1

Japan Atomic Energy Agency (JAEA)
Chiba Institute of Technology
3
Kyushu University
2－ 29 －

JAEA-Review 2008-054

20˚ to 67˚ and from 113˚ to 160˚ to the incident beam direction. The angular resolution was 3.1˚ in FWHM
near the edge of the detector and 1.9˚ at the center. The information on a particle position was used for
Doppler-shift corrections of the γ rays from 100Ru, simultaneously providing the impact-parameter
dependence of the γ-transition intensity. The experimental data were recorded event by event on a hard disk
when one Ge detector and one particle detector gave coincident signals. Figure 1 gives an example of
Doppler-corrected spectra of γ rays in coincidence with scattered particles. The typical energy resolution of
Doppler-corrected γ-ray peaks was approximately 1.0%.
Thirteen γ-ray peaks were identified as the γ rays of 100Ru. By connecting the observed transitions, we canconstruct the level scheme of the ground band and low-lying band structure. The detailed data analysis of
this experiment is in progress with the least-squares search code GOSIA [9,10], which will reveal the B(E2)and B(E3) transition probabilities and some of the quadrupole moments. This will help us to understand the
low-lying collective mode of 100Ru.

References[1] D. Troltenier et al., Z. Phys., A338 (1991) 261-270.
[2] A. Flank, Phys. Rev., C 39 (1989) 652.
[3] F. Iachello, Phys. Rev. Lett., 85 (2000) 3580-3583.
[4] F. Iachello, Phys. Rev. Lett., 87 (2001) 052502[1]-[4].
[5] K. Alder and A. Winther, Coulomb Excitation, Academic, NewYork, (1966).
[6] K. Alder and A. Winther, Electromagnetic Excitation, North Holland, Amsterdam, (1975).
[7] K. Furuno et al., Nucl. Instrum. Methods Phys. Res., A421 (1999) 211-226.
[8] Y. Toh et al., Rev. Sci. Instrum., 73 (2002) 47-50.
[9] T. Czosnyka et al., Nucl. Phys., A 458 (1986) 123-136.
[10] T. Czosnyka, C.Y. Wu and D. Cline, Bull. Am. Phys. Soc., 28 (1983) 745-746.

－ 30 －

JAEA-Review 2008-054

2. 4 In-beam gamma spectroscopy of 168Ta
Y.H. Qiang 1,2, Y.H. Zhang1, X.H. Zhou1, M. Oshima 3, M. Koizumi3, Y. Toh3, A. Kimura3,
H. Harada3, K. Furutaka3, F. Kitatani3, S. Nakamura3, Y. Hatsukawa3, M. Ohta3,
K. Hara3, T. Kin3, and J. Meng 4

As a part of research work to investigate band structures of odd-odd nuclei in the A=170 mass region, thehigh-spin states in odd-odd 168Ta have been investigated via the 145Nd(27Al, 4nγ) reaction at a beam energyof 140 MeV. The 27Al beam was provided by the tandem accelerator in the Japan Atomic Energy Agency.
The target was a 2.5 mg/cm2 145Nd neodymium powder evaporated onto an 8 mg/cm2 Au backing. The
in-beam γ rays were detected using the gamma detector array of GEMINI-II [1] which consists of 19
HPGe’s with BGO anti-Compton shields. A total of 3×108 γ-γ coincidence events were accumulated. The
experimental data were analyzed in a same way as described in ref. [2].
The level scheme of 168Ta, which is composed of two strongly coupled bands, was established andpresented in fig. 1 as band 1 and 2. Compared with the previous result of Theine et al. [3], the present level
scheme was extended both to higher- and lower-spin states. In particular, the 121-keV γ-ray in band 1 has
been assigned as an out-of-band transition rather than the in-band transition as proposed in ref. [3]. This is
supported by the observation of a 266.7-keV cross-over transition and coincidence relationships between
the 121- and 198-keV γ-rays and others. The 225-keV cross-over transition reported in ref. [3] has not been
observed in this work. Although a number of doublet or triplet γ rays appear in band 2, this band has been
extended up to (27+) due to high statistics of the data.
Band 1 and 2 have been assigned to be built on the πh11/2⊗νi13/2 and πd5/2⊗νi13/2 2-qp configurations,
respectively. This configuration assignment is supported by the measured in-band B(M1)/B(E2) ratios asshown in fig. 2. One can see in this figure that the experimental B(M1)/B(E2) ratios can be well reproduced
theoretically under the assumption of the proposed configurations. On the other hand, since the one-qp
bands built on the πh11/2, πd5/2, and νi13/2 intrinsic states in neighboring odd-A nuclei were strongly
populated in heavy-ion-induced fusion-evaporation reactions, it is naturally expected that the πh11/2⊗νi13/2
and πd5/2⊗νi13/2 bands in odd-odd nuclei may lie close to the yrast line and be observed intensely. Indeed
such bands have been identified in the neighboring 170Ta [4], providing a supplementary evidence for ourconfiguration assignments. No connection to the ground state of 168Ta could be established for these bands,
the spin assignments are based on level spacing systematics and additivity rule of quasiparticle alignmentsin the crancked shell model.
Further analysis is still in progress and the final result will be published in a coming article.

1

Institute of Modern Physics, Chinese Academy of Sciences2

Graduate School of Chinese Academy of Science
Japan Atomic Energy Agency (JAEA)
4Peking University
3－ 31 －

JAEA-Review 2008-054

Fig. 1 Partial level scheme of 168Ta established in the present work.

Fig. 2 In-band B(M1)/B(E2) ratios extracted from the present experiment. The solid lines aretheoretical calculations using the proposed configurations indicated in the figure.

References[1] M. Oshima et al., J. Radioanal. Nucl. Chem., (2008) to be published.
[2] Y. H. Zhang et al., Phys. Rev., C68 (2003) 054313.
[3] K. Theine et al., Nucl. Phys., A536 (1992) 418.
[4] Y. H. Zhang et al., Phys. Rev., C60 (1999) 044311.

－ 32 －

JAEA-Review 2008-054

2. 5

Isomers in neutron-rich tantalum isotopes

T. Shizuma 1, T. Ishii1, H. Makii1, T. Hayakawa1, M. Matsuda1, E. Ideguchi 2, and T. Morikawa 3

In A～180 nuclei, low-lying isomers due to the K quantum number conservation (where K is defined as theangular momentum projection on the nuclear symmetry axis) are systematically observed. The majority of
K isomers in this region are found in nuclei on the neutron-deficient side of the valley of β stability,
because of the inaccessibility to the neutron-rich nuclei using fusion-evaporation reactions with stable beamand target combination. However, the recent progress in γ-ray spectroscopic techniques using 18O-induced
transfer reactions has enabled us to investigate the near-yrast structures of neutron-rich nuclei [1,2].
Excited states in neutron-rich Ta nuclei have been populated in 18O-induced transfer reactions on 186W and181

Ta targets. The 180-MeV 18O beams were provided by the tandem accelerator at Japan Atomic Energy

Agency, Tokai. The target thickness was thick enough to stop residual nuclei inside the target materials.
Outgoing projectile-like ions were detected by four sets of surface barrier Si ΔE-E detectors placed at a
position close to the grazing angle of the reactions used. In-beam γ rays were measured by eight HP-Ge
detectors in coincidence with the scattered ions. Four of these detectors with relative efficiency of 60%
were arranged symmetrically in a plane perpendicular to the beam axis at a distance of 6 cm from the40

reaction of 186W(18O,19F) [3]. Several γ-ray peaks

30

Countsfound in 185Ta produced by the one-proton pickup
were observed above this isomer as shown in fig.
1. The data obtained in the 181Ta+18O reaction
also reveal the existence of an isomer in 183Ta

20
10

483

a K =1/2 , T1/2=900 ns isomer at 406 keV was

403

50

+

298
327

π

183
189 19F

From the analysis of the delayed coincidence data,

Ta KX rays

targets.

400

500

produced by the two-neutron transfer. Further
00analysis of this data is in progress.

100

200
300
Energy (keV)

Fig. 1 A γ-ray coincidence spectrum gated on the
delayed 406 keV transition in 185Ta produced in the18
O-induced reaction on 186W.
References[1] T. Ishii et al., Phys. Rev., C72 (2005) 021301(R).
[2] T. Shizuma et al., Eur. Phys. J., A30 (2006) 391-396.
[3] T. Shizuma et al., Eur. Phys. J., A34 (2007) 1-4.
1Japan Atomic Energy Agency (JAEA)
Tokyo University
3
Kyushu University
2－ 33 －

JAEA-Review 2008-054

2. 6

Prolate and oblate shape co-existence in 188Pt 

X.H. Zhou1, M. Oshima2, Y. Toh2, M. Koizumi2, A. Osa2, Y. Hatsukawa2,
Y.H. Zhang1, and M. Sugawara3
Shape coexistence is a major theme in nuclear structure study. The neutron-deficient Pt-Hg nuclei withneutron number N∼110 are well known to exhibit interesting shape co-existence phenomena [1]. The
isotope shift measurements have shown a sharp change of the nuclear charge radius around 188Pt [2],suggesting an oblate ground-state shape for the Pt nuclei with A>188 and a near prolate shape for A<188.
Therefore, the spectroscopic information of 188Pt is of particular interest as it would show competingcollectivity of prolate and oblate shapes. Prior to the present work, the high-spin level scheme of 188Pt wasreported in the literature [3].

Fig. 1 A partial level scheme of 188Pt.

Fig. 2 Energy surface calculation for 188Pt
obtained with projection on quasi-particle
vacuum states only.

The excited states in 188Pt were populated via the 176Yb(18O, 6n) reaction. The 18O7+ beam was provided by
the tandem accelerator at the Japan Atomic Energy Agency (JAEA). The target was an isotopically enriched176
Yb metallic foil of 2.0 mg/cm2 thickness with a 7.0 mg/cm2 Pb backing. The γ-ray detector array,
GEMINI-II, at JAEA was used [4].γ-γ-t coincidence measurements were performed at beam energies of 88
and 95 MeV, at which energies the yields of 188Pt were large. A total of 240×106 coincidence events wereaccumulated. After accurate gain matching, these coincidence events were sorted into symmetric and DCO
matrices for off-line analysis. Assignments of the observed new γ-rays to 188Pt were based on the1

Institute of Modern Physics, Chinese Academy of Sciences
Japan Atomic Energy Agency (JAEA)
3
Chiba Institute of Technology
2－ 34 －

JAEA-Review 2008-054

coincidences with the known γ-rays [3]. Gated spectrum was produced for each of the γ-rays assigned to
Pt. On the basis of the analysis of γ-γ coincidence relationships, a partial level scheme for 188Pt has been
proposed and presented in fig. 1. The transition character was deduced from the measured DCO results.

188

Variant kinds of nuclear models have been applied to study nuclear shape co-existence. The Projected Shell
Model (PSM) [5] is a shell model that uses deformed bases and the projection technique. The PSM's
two-body residual interactions are of the quadrupole plus pairing type, with the quadrupole-pairing term
included [5]. The calculated energy surface for 188Pt is shown in fig. 2. These curves show the energies forstates with different angular momenta while varying deformation ε from negative values to positive
values. There are two pronounced minima, sitting respectively at the prolate and oblate side. Therefore, thecalculation predicts a competing between prolate and oblate shapes with two sets of corresponding
collective states. The minimum ε ≈0.16, corresponding to a prolate shape, is lower in energy. The
calculations suggest that the ground state of 188Pt has a prolate shape. Comparing the calculated results withthe experimental observation, we can assign the level sequence, shown in the right hand of fig. 1, as aprolate band built on the ground state, and the rotational band based on the 605.5-keV state as an oblate
band. Therefore, the transitional nucleus 188Pt presents an excellent example of prolate and oblate shape
co-existence.
Very recently, a new kind of shape phase transition, occurring along an yrast line between states of prolate
and oblate shape in an isolated nucleus 190W, has been predicted by Sun et al [5]. However, theexperimental data on the exited states of 190W is sparse due to its neutron richness, and the predicted shapephase transition has not yet been proven experimentally. As shown in fig. 1, the yrast states up to the spinvalue of 10 h are the members of the ground state band. However, the yrast states change to the states
based on the 12+ level depopulated by the 328.8-keV transition. If the shape is oblate, occupation of low-K
i13 2 neutron intruder orbits favors rotation alignment. The νi132 2 configuration was proposed to the 12+
state. The level scheme of 188Pt clearly shows that the path for the lowest state at each I starts from theprolate ground state, goes up till I=10, and then jumps to the oblate side. The wave functions for the prolate
and oblate shapes should be very different, with a very small overlap between them. It is expected that the
oblate state at the phase transition point might be a shape isomer. Indeed, the yrast 12+ state was identified
to be an isomer [3], and theγtransition between the oblate and prolate states was strongly hindered.
Therefore, a prolate to oblate shape phase transition might occur along the yrast line in 188Pt. In the present
case, the order parameter is the total spin I.

References[1] D. T. Joss et al., Phys. Rev., C74 (2006) 014302-10.
[2] H. T. Duong et al., Phys. Lett., B217 (1989) 401-405.
[3] M. Piiparinen et al., Phys. Rev. Lett., 34 (1975) 1110-1113.
[4] M. Oshima et al., J. Radioanal. Nucl. Chem. (2008) to be published.
[5] Y. Sun et al., Phys. Lett., B659 (2008) 165-169.

－ 35 －

JAEA-Review 2008-054

2. 7

Gamma-rays in ground-state band of 246Pu

H. Makii 1, T. Ishii2, M. Asai2, K. Tsukada2, A. Toyoshima2, M. Matsuda2, A. Makishima3
J. Kaneko4, H. Toume2,5, S. Ichikawa2, S. Shigematsu2,6, T. Kohno6, and M. Ogawa4

We have measured deexcitation γ-rays in neutron-rich transuranium nuclei of 246Pu for the first time. The
246

Pu was produced by the (18O, 16O) two-neutron transfer reaction. A 244Pu target (98.0 % enrichment in

244Pu), 0.7 mg/cm2 in thickness and 3 mm in diameter, electrodeposited on a 3.4 μm aluminum foil wasbombarded by a 162 MeV 18O beam of 0.3 particle nA. Outgoing projectile-like particles were detected byfour sets of Si ΔE – E detectors. γ rays emitted from the residual nuclei were measured by six Ge detectors,
in coincidence with outgoing particles. A detailed description of the measurement system is given inref. [1].
Deexcitation γ rays in 246Pu were identified by setting a gate on 16O particles with kinetic energies
corresponding to the excitation energies of 246Pu between 0 and 6 MeV. γ rays in the ground-state band of246

Pu were clearly observed as shown in fig. 1. These γ rays were coincidence with each other. Furthermore,

the in-plane to out-of-plane intensity ratios of these γ-rays confirm that these transitions are stretched E2
types. On the basis of these results, we have established the ground-state band of 246Pu up to 12+ as shownin fig. 2. In fig. 1, the 2+ → 0+ γ ray of about 47 keV was not observed owing to its large internalconversion coefficient (αT ≈ 600 [2]). γ-rays in 245Pu produced by one-neutron evaporation from 246Pu

50

222

245

275

Pu(163)

323

244

108
100

Pu(194)

167

Kα1
500

Kβ2 Kβ1 + Kβ3

Kα2
Pu(75)

1000

245

Counts / 0.33 keV

following the (18O, 16O) reaction are also seen in fig. 1.

150

200

250

300

350

Eγ (keV)Fig. 1 A γ-ray spectrum in coincidence with 16O particles with kinetic energies
corresponding to the excitation energies of 246Pu between 0 and 6 MeV. γ peaks of246
Pu are labeled by energies in units of keV.
1

High Energy Accelerator Research Organization (KEK)
Japan Atomic Energy Agency (JAEA)
3
National Defense Medical College
4
Komazawa University
5
Ibaraki University
6
Tokyo Institute of Technology
2－ 36 －

JAEA-Review 2008-054

Figure 3(a) shows systematics of the 2+ energies E(2+) for the ground-state bands of even-even actinide
nuclei whose excitation energies were measured precisely. The E(2+) values were derived from the momentof inertia deduced from the higher levels. Sobiczewski et al. [3] calculated the E(2+) energies on the basisof a macroscopic-microscopic approach taking account of higher order deformations and a cranking
approximation. The calculated values are shown in fig. 3(b). This calculation predicted and reproduced thesystematics of the E(2+)values around N = 152 very well. They pointed out that the pairing gap becomes
smaller at a deformed shell gap, which leads to large values of the moment of inertia and, as a result, tosmall values of the E(2+) at N = 152. In fig. 3, the E(2+) values for isotopes from 96Cm to 102No are pulled
down to lower energies at N = 152. In contrast, the E(2+) values for 94Pu isotopes increase gradually withneutron number. This systematics of the E(2+) values suggests that the deformed shell-gap size at N = 152
is reduced in 94Pu isotopes. The reduction of the shell-gap size of N = 152 was confirmed from one-quasi
levels in 245Pu as described in ref. [4].
1141

12+

322.7
818

10+

544
222.4
321

6+
166.6
4

155

+

2+
0+

107.8
246

E(2+) (keV)8

Pu102No 94

46

274.6
+

92U

(a)

48

100Fm

44
98Cf

96Cm

42

U

(b)

48

Pu

Cf
Cm

Fm

46

No

44
42

47
0

140

142

144

Pu152

Fig. 2. Level scheme of the groundstate band of 246Pu. The energy of the2+ level was derived from themoment of inertia deduced from thehigher levels.

146

148

150

Neutron Number

152

154

156

Fig. 3. (a) Systematics of the 2+ energies E(2+) for the
ground-state bands of even-even actinide nuclei. Because
there are no accurate measurements for 252Fm152, the datafor 250Fm and 254Fm are connected by a dashed line. (b)Calculated E(2+) energies by a macroscopic-microscopic
approach [3].

References[1] T. Ishii et al., J. Phys. Soc. Jpn., 75 (2006) 043201.
[2] I. M Band et al., At. Data Nucl. Data Tables, 81 (2002) 1-334.
[3] A. Sobiczewski, I Muntian and Z. Patyk, Phys. Rev., C 63 (2001) 034306.
[4] H. Makii et al., Phys. Rev., C 76 (2007) 061301(R).
－ 37 －

JAEA-Review 2008-054

Quasi-particle states in 249Cm measured by in-beam γ-ray spectroscopy

2. 8

T. Ishii 1, H. Makii1, M. Asai1, K. Tsukada1, A. Toyoshima1, M. Matsuda1, A. Makishima2,
S. Shigematsu3, J. Kaneko4, T. Shizuma1, H. Toume1, I. Hossain5, T. Kohno3, and M. Ogawa4

We have measured deexcitation γ-rays in 249Cm populated by one-neutron stripping reactions with a 248Cm
target and a 162 MeV 16O, a 162 MeV 18O, and a 120 MeV 13C beams. γ rays in 249Cm were identified by
selecting outgoing particles and measuring their kinetic energies using Si Δ E-E detectors [1-4]. We haveobserved eight quasi-particle states above the deformed shell gap of N=152. The level scheme is shown infig. 1. The 1/2[620], 1/2[750], and 7/2[613] bands were extended up to 19/2+, 19/2-, and 13/2+ states,
respectively. We have established the 9/2+ 9/2[615] state at 526.3 keV, the 9/2+ 9/2[604] state with a shortlife (T1/2<< 2ps) at 1029.8 keV, and the 11/2- 11/2[725] state with a half life of 19(1) ns at 375.1 keV.
Furthermore, the 17/2+ member of the 1/2[880] state originated from the k17/2(L=8) spherical single-particle
state was assigned to a level at 1504.8 keV. The γ-ray spectra for the 637 keV transition depopulating thisstate are shown in fig. 2. The 1505 keV level is close in energy to one of the candidates for the17/2+
1/2[880] state observed by the (4He, 3He) reaction using a magnet spectrometer [5]. We have also
demonstrated that higher-spin states were populated in the (16O, 15O) reaction with Qgg= -11.0 MeV thanthose in the (13C,12C) reaction with Qgg= -0.2 MeV as shown in fig. 3. This is caused by the matchingcondition of angular momentum.
1/2[880]
17/2 + 1504.8

233.7

15/2

+

17/2

+

498.6

429.8

.1
27
8.
5

663.5

40
0

19/2+

36
9.7

636.5

199.6

11/2

+

13/2 +
244.8

9/2 +
7/2
110.17+
3/2+ 26.24 5/2
134.6
+

1/2

+

299.0
150.6
148.4

4
45 353 29.1
3.8 .6185.0

249

19/2 −

868.3

15/2 −

699.1

11/2 −
7/2−
3/2−

Cm 153

9/2[604]
9/2 +

981.1

9/2[615]577.5

9/2 + 526.3−

502.0 1/2
470.21 494 .49

1/2[750]48.20

1029.8

11/2[725]
11/2 −

4 17.0

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

288.97242.00208.003/2[622]

13/2

+

268.7

11/2 + 86.0 182.7
9/2 + 73.6 109.4
7/2 + 60.8 48.74

0 k eV

477.6

192.5

265.7

7/2[613]

1/2[620]

Fig. 1 Level scheme of 249Cm. γ-rays observed in the (16O,15O) reaction are depicted.
1Japan Atomic Energy Agency (JAEA)
National Defense Medical College
3
Tokyo Institute of Technology
4
Komazawa University
5
Osaka University
2－ 38 －

375.1

T 1/2=19(1) ns

JAEA-Review 2008-054

(a)
981

637

γ - 15O

2
1
0
600

700

800
900 1000γ-ray Energy (keV)

20

1100

γγ - 15O

1200

(b)

(gate: 370keV)
637

185
200

10
135

Counts /1.34keV

Counts /2keV[×102] 4
3

Fig. 2 γ-ray spectra for the 637
keV transition depopulating the
1/2[880] band.
(a) γ-ray spectrum in coincidencewith 15O. (b) γγ coincidence
spectrum by setting the gate on the
370 keV transition. Both spectra
were obtained by the (16O, 15O)
measurement.

0
0

200
400
γ-ray Energy (keV)

600

103
−

1/2 [750](13C,12C)

Population Yield (μb)

Qgg= −0.2 MeV

102

18

17

( O, O)

Qgg= −3.3 MeV

16

15( O, O)

101

Qgg= −11.0 MeV

Fig. 3 Population yields for members of the
1/2[750] band in 249Cm. These yields wereobtained from the intensities of γ rays
depopulating these states.

100
1/2 3/2

7/2

11/2 15/2 19/2

Spin

References[1] T. Ishii et al., Phys. Rev., C72 (2005) 021301(R)(1-5).
[2] T. Ishii et al., J. Phys. Soc. Japan, 75 (2006) 043201(1-4).
[3] T. Ishii et al., Phys. Rev., C76 (2007) 011303(R)(1-5).
[4] H. Makii et al., Phys. Rev., C76 (2007) 061301(R)(1-5).
[5] I. Ahmad, Nucl. Phys., A646 (1999) 175-186.

－ 39 －

JAEA-Review 2008-054

2. 9 Alpha-gamma coincidence spectroscopy of 259No
M. Asai1, K. Tsukada1, M. Sakama2, Y. Ishii1, A. Toyoshima1, T. Ishii1, I. Nishinaka1, Y. Nagame1,
Y. Kasamatsu1, M. Shibata3, H. Hayashi3, H. Haba4, and Y. Kojima5

The stability of superheavy nuclei essentially depends on nuclear shell structure. Many theoretical studies
have predicted the stability and shell structure of superheavy nuclei, while experimental information is very
scarce. In this work, α-γ coincidence spectroscopy of 259No has been performed to establish excited statesin the daughter nucleus as well as to assign spin-parities and single-particle configurations of the groundstate of 259No. Having the neutron number N = 157, 259No is one of the most neutron-rich nuclei thatexperimental spin-parity assignments have ever been performed for. These experimental data allow us to
extract energy spacings and order of single-particle orbitals, which are direct measure to see the shellstructure of superheavy nuclei.
259

No was produced by the 248Cm(18O,α3n) reaction whose maximum cross section is about 13 nb. The

beam energy was 94 MeV on target. Reaction products recoiling out of the target were continuouslytransported through a 20-m long capillary with a He/KCl aerosol jet into a rotating wheel α-γ detection
system, and were deposited on a thin foil forty of which were set on the wheel [1]. The wheel periodicallyrotated to move the deposited sources to two consecutive detector stations each of which were equippedwith two Si detectors and two Ge detectors. Since the half-life of 259No is 58 min, we rotated the wheel at
2400-s intervals. However, the collection of KCl aerosol for such a long time results in a deposition of KClmaterial too thick to measure α-energy spectra. To prepare much thinner sources, a tip of the capillary was
moved to draw an 8-mm diameter circle on the foil, which reduces the thickness of the deposited KCl by
about an order of magnitude. Alpha-singles and α-γ coincidence events were recorded event by event
together with time information.
Figure 1(a) shows a γ-ray spectrum in coincidence with α particles of 259No. About 900 α-singles eventswere accumulated for a total of 9-day experiment. Three weak γ rays were observed at 61.7, 169.9, and231.4 keV in addition to intense Fm K and L X rays. The decay scheme of 259No was established as shownin fig. 1(b). From K X- to γ-ray intensity ratios, the 169.9 and 231.4 keV γ rays were found to be M1/E2
transitions.
The spin-parity and neutron configuration of the ground state of 255Fm is known to be 7/2+[613] [2]. The
first excited 61.7 keV level is considered to be the 9/2+ state in the 7/2+[613] rotational band by analogy
with neighboring nuclei. The 231.4 keV level is populated by the favored α transition, indicating that this1

Japan Atomic Energy Agency (JAEA)The University of Tokushima
3
Nagoya University
4
The Institute of Physical and Chemical Research (RIKEN)
5
Hiroshima University2－ 40 －

JAEA-Review 2008-054

level should be a one-quasiparticle state with the same configuration as that of the ground state of 259No.
The 231.4 keV level is depopulated by the M1/E2 transitions to the 7/2+ and 9/2+ states, which restricts the
spin-parity of the 231.4 keV level to 7/2+ and 9/2+. Around 259No, only the 9/2+[615] orbital exists near the
Fermi surface with Ω = 7/2+ or 9/2+, except the 7/2+[613] orbital which is already assigned to the groundstate of 255Fm. Thus, we have assigned the 9/2+[615] configuration to the 231.4 keV level in 255Fm as wellas to the ground state of 259No. Note that the 169.5 and 231.1 keV γ rays were also observed in the EC
decay of 255Md [3]. This experiment also suggested the 9/2+[615] configuration for the 231.1 keV level,
consistent with the present result.
It is found that the α decay scheme of 259No is very similar to that of the N = 157 isotone 257Fm; theground-state configuration of both the nuclei is 9/2+[615], and the 9/2+[615] state in the daughter nuclei islocated at 241 keV in 253Cf and 231 keV in 255Fm. On the other hand, theoretical calculations predicted the
9/2+[615] states at 300–400 keV in N = 155 isotones [4,5], and could not reproduce the 9/2+[615] groundstates for N = 157 isotones; the 9/2+[615] states were calculated at 200–300 keV above the ground state[4,5]. This indicates that the location of the 9/2+[615] orbital is too high in the calculations, probably due to

0
0

231.4

+

9/2+
+

7/2 [613] 7/2

100
200
Gamma-ray Energy (keV)

300

9/2+[615]
9/2+

No

231.4

+

255

259

α

61.7

+

9/2 [615] 9/2

231.4 M1/E2
169.6 M1/E2No

α-γ coincidence

169.6

10

(b)

259
Fm Kβ XFm Kα X

20

61.7

Counts / 0.8 keV(a)

Fm L X

inadequate deformation parameters used in the calculations.

61.7
0

Fm

Fig. 1 (a) Gamma-ray spectrum observed in coincidence with α particles of 259No. (b) Proposed decay
scheme of 259No.

References[1] Y. Nagame et al., J. Nucl. Radiochem. Sci., 3 (2002) 85-88.
[2] F. Asaro, S. Bjørnholm and I. Perlman, Phys. Rev., 133 (1964) B291-B300.
[3] I. Ahmad, R.R. Chasman and P.R. Fields, Phys. Rev., C61 (2000) 044301.
[4] S. Ćwiok, S. Hofmann and W. Nazarewicz, Nucl. Phys., A573 (1994) 356-394.
[5] A. Parkhomenko and A. Sobiczewski, Acta Phys. Pol. B, 36 (2005) 3115-3137.

－ 41 －

JAEA-Review 2008-054

2.10 Decay study on fission products with on-line isotope separator
M. Shibata1, M. Asai2, A. Osa2, M. Oshima2, A. Kimura2, M. Koizumi2, and T. K. Sato2

Atomic masses are the most fundamental physical quantities and play an important role for study on structure of
unstable nuclei, nuclear stability or nucleosynthesis in astrophysics. Beta-decay energy (Qβ) measurement is one ofthe precise methods to determine atomic masses and it is also important for evaluation of the decay heat of thenuclear power plants in nuclear engineering. We had already developed two type total absorption detector to measureQβs of low yielded nuclei such as new isotopes [1,2]. At first, using a BGO total absorption detector, we succeeded in
Qβs determination of some new fission products produced with 238U(n,f) reaction with the accuracy of 60 keV [1].
Next, a total absorption detector, which are composed of a large volume Ge detector having a through hole in thecenter itself and a surrounding annular BGO Compton suppression detector, was developed. It was also applied toQβ energy measurements and succeeded in determination them within 20 keV [3]. However, the efficiency of the Ge
detector and the solid angle of the BGO Compton suppression are still small, then, the efficiency as the total
absorption detector is less effective for the nuclei having Qβ higher than 5 MeV. So the 3rd total absorption detector
with high-efficiency and high-resolution have been developed. This detector is composed of large volume clover
detector (80 mmφ × 90 mmt × 4) having a through hole (15 mmφ) in the center, and five BGO Compton suppression
detectors (2 × top, 2 × side, 1 × bottom, each is 30 mm thick.) which surround the clover detector with almost 100%solid angle. Scattered photons by clover detector are detected with BGO detectors with high efficiency, then Qβs forthe fission products are expected to be measured up to 10 MeV with the accuracy of 20 keV. The determinations of
the Qβs for rare isotopes including new isotopes are useful for mass prediction in neutron-rich nuclei and also decay
heat evaluation. In this experiment, the performance of the detector was tested by measuring the Qβs for the nuclei
with mass number A ~ 90 or 140.
Uranium carbide (UC2) target containing 670 mg/cm2 238U was bombarded with 30 MeV proton beams with theintensity of about 10nA generated by the TANDEM accelerator at JAEA. The 88,89Rb, 92-95Y, 138,139Cs, 139Ba and142,143

La isotopes were separated from the fission products by an on-line isotope separator (Tokai-ISOL). The Qβs

and half-lives for the nuclei are between 2 and 5.4 MeV, and between 9.3 min and 3.5 h, respectively. The
radioactive ion beams were implanted into thin Mylar tapes and were put into the center position of the clover
detector. Singles spectra with the clover detector and coincidence spectra between the clover and the BGO detectors
were also measured. These procedures were iterated many times to get good statistics for every nucleus. The
measurement period for each nucleus was between 4 and 10 hours. The counting rate of each activity was kept
around 2 kcps to reduce pulse pile-ups.
The total absorption events were extracted by subtracting the coincidence spectra by multiplied a factor of 1.25 fromthe singles one. This factor was determined from the experimental analysis for the monoenergetic γ-rays and also
from the Monte Carlo simulation (GEANT4). Typical total absorption spectrum of 88Rb is shown in fig.1 together
with singles and coincidence ones. The end-point energies were deduced by processing the folding spectra to total
1
2

Nagoya University
Japan Atomic Energy Agency (JAEA)－ 42 －

JAEA-Review 2008-054

absorption spectra as shown in fig.2 using the simulated response functions for monoenergetic electrons by
GEANT4 parameterized as shown in fig.3.
By measuring the eleven nuclei which Qβs are well determined [4], then the performance of the detector concerning
the determination of Qβ was evaluated. It is found that the experimental Qβs are a certain value, which corresponds tothe energy loss owing to the well of the detector, smaller than the values in ref. 4 (fig. 4) and it was evaluated to be
190 ± 20 keV for the Qβvalues between 2.3 and 5.4 MeV. As the results, this total absorption detector are expected todetermine the Qβs of rare isotopes precisely including new isotopes.

Fig. 1 Typical total absorption spectrum of88
Rb. The solid line indicates the total
absorption events.

Fig. 2 End-point analysis of 88Rb byfolding procedure.

Fig. 4 The evaluation of the energy loss forthe detector.

Fig. 3 Typical response function formonoenergetic electrons of 5 MeV.

Present study includes the result of "Study on nuclear data by using a high intensity pulsed neutron source foradvanced nuclear system" entrusted to Hokkaido University by the Ministry of Education, Culture, Sports, Scienceand Technology of Japan (MEXT).
References[1] M. Shibata et al., J. Phys. Soc. Jpn., 71 (2002) 1401-1402.
[2] H. Hayashi et al., Euro. Phys. J., A 34 (2007) 363-370.
[3] H. Hayashi et al., Int. Conf. on Nucl. Data for Sci. and Tech., Nice, France, April 22-27, 2007.
[4] G. Audi et al., Nucl. Phys., A 729 (2003) 337-676.

－ 43 －

JAEA-Review 2008-054

2.11

A gas cell for on-line laser spectroscopy of radioactive isotopesof refractory elements
H. Iimura 1, M. Miyabe1, M. Oba1, and M. Koizumi1

High resolution laser spectroscopy of radioactive isotopes can provide important information on nuclear
structure such as the electromagnetic moments and the changes of nuclear charge radii. However, those
information are scarce for the radioactive isotopes of refractory elements such as in the rhenium region,
since usual collinear laser spectroscopy using an ion source can not be applied to these isotopes. We plan to
do laser spectroscopy for these isotopes by stopping the recoiled reaction-products in gas. They areirradiated with the laser beam while diffusing through the gas. The gas cell for this experiment has recently
been set up in a beam line of the JAEA tandem accelerator in Tokai. In this report we describe an overview
of the gas cell. Similar gas cell has already been constructed at the Stony Brook tandem accelerator facility
and successfully used for the isotope-shift measurements of radioactive ytterbium isotopes [1].
The basic geometry of the gas cell is shown in fig. 1. The nickel foil window isolates the gas cell from theaccelerator beam line. By filling the cell with about 10 Torr of argon gas, the reaction products being
recoiled from the target stop at the center of the inner cell where they are illuminated by the laser beam.
Photomultiplier
tube
Lens

FilterInner cell
Laser beam

MirrorLiquid nitrogen reservoir

Laser beam

Beam stop

TargetNi foilIon beam fromaccelerator

0

10

20 cm

Fig. 1 Schematic layout of the gas cell. The upper and lower sections of the figure areside and top views of the cell, respectively.
1

Japan Atomic Energy Agency (JAEA)－ 44 －

JAEA-Review 2008-054

The inner cell is connected on the liquid nitrogen reservoir. By cooling the inner cell, the gas is cooled andthus the Doppler width of the resonance peak becomes narrower. At the gas temperature of 150 K, theDoppler width is expected to be about 300 MHz. This cooling also helps to increase the fluorescence yield
since the time for the reaction products to diffuse out from the laser beam becomes longer. The
laser-induced fluorescence is collected on a photomultiplier tube by using a mirror and lenses. The
resonance peaks are observed by scanning the frequency of a tunable laser. Since the production rate ofradioactive isotopes by heavy-ion fusion reaction is expected to be less than 105 atoms/sec, it is importantto reduce the background to observe the laser-induced fluorescence signal. The largest part of the
background is the light coming from the collisions between the argon atoms and the ions from theaccelerator. To reduce this background a beam-stop consisting of a disk 7.5 mm in diameter is placed
between the target and the inner cell. While it blocks most part of the ion beam from the accelerator, someof the reaction products can get into the inner cell because low-energy recoils undergo small-angle
scattering when they pass through the target and gas. Additionally, the ion beam is chopped by using a
deflector, and the counter of the photomultiplier is gated so that it record only when the ion beam is off.
Prior to studies of radioactive isotopes in the rhenium region, we are now working to optimize thesensitivity of the apparatus. Particularly, the transition for laser excitation is crucial to achieve highsensitivity. In order to find the most efficient transition, we will use the ion beams of stable isotopes ofthese elements. These ions are injected from the accelerator into the gas cell without the beam stop. By
exciting some transitions with laser, we can determine the transition which has the strongest laser-induced
fluorescence.

References[1] A. Berger et al., Nucl. Instrum. Methods Phys. Res., A311 (1992) 224-239.

－ 45 －

JAEA-Review 2008-054

2.12

On-line test of RI ion trap system

H. Makii 1, T. Ishii2, D. Nagae2, T.K. Sato2, A. Osa2, and S. Ichikawa 2

The low-energy and low-emittance pulsed radioactive nuclear beam (RNB) is useful for the measurementsof fundamental properties of nucleus such as binding energy, charge radius, and magnetization distribution
with high accuracy. Construction of a new beam line and an RF linear ion trap for deceleration, bunching,and emittance improvement of RNB is now in progress at a central beam line of an isotope separator
on-line (ISOL). The overview of the beam line and trap system is given in ref. [1]. By adjusting the ion
optical elements, the continuous ion beam from an ISOL is transported to the trap. The transported ions areelectrostatically decelerated and injected into the trap, which is filled with a buffer gas. The trap system
consists of four segmented rods which provide transverse and longitudinal confinement by an oscillating
electric quadrupole field and DC electric field along the axis of the system, respectively. Ions entering thetrap system lose their energy due to the collision with the buffer gas, and then the cooled ions are extracted
as bunches [2].
On-line test of the trap system was carried out using unstable 21Na+ (t1/2 = 22.49 s), 92Rb+ (t1/2 = 4.492 s),
and 142Cs+ (t1/2 = 1.70 s) beams provided by the ISOL. The 21Na was produced by 12C + 12C fusion reaction,and the 92Rb and 142Cs nuclei were produced by proton-induced fission of uranium. The beam energies
from the ISOL were 21 keV. The extracted ions were stopped on a Micro-channel plate (MCP) detector
placed on the exit of the trap system and we measured time distributions of the ions with the MCP detector.
Figure 1 shows the time-of-flight spectrum of 21Na+ ions ejected out of the trap system. We also measured
the γ-rays emitted by daughter nuclei with a Ge detector placed near the MCP detector. The γ-rays emitted
by 21Na, 92Rb and 142Cs were clearly observed in figs. 2(a), 2(b) and 2(c), respectively. From the result of
this on-line test, it is proved that our new trap system has capability to decelerate and bunch the unstableions up to A ~ 140. Systematic investigations of trap system to improve efficiency for heavier ions (A >Counts / 0.24 μs200) are now in progress.

Accumulation : 750 μs
Extraction : 50 μs

30
20Width:
12 μs

10
0

0

200

400

Time [μs]

600

800

Fig. 1 Time-of-flight spectrum of 21Na+ ions ejected out of the trap system.
1
2

High Energy Accelerator Research Organization (KEK)
Japan Atomic Energy Agency (JAEA)－ 46 －

JAEA-Review 2008-054

10511(e++e-)

21
Na
1 (a)

351

100

Counts / 0.5 keV

10-1
92
101 (b) Rb

10

815
570

0

10-1
10

1

(c) 142Cs 360

100
10-1
200

400

600

800

Eγ [keV]Fig. 2 γ-ray spectra taken by Ge detector. γ-ray peaks of decaying 21Na (a), 92Rb (b)and 142Cs (c) are labeled by energies in units of keV.

References[1] H. Makii et al., JAEA-Tokai TANDEM Ann. Rep. 2005, JAEA-Revew 2006-029 (2006) 37-38.
[2] F. Herfuth et al., Nucl. Instrum. Methods Phys. Res., A469 (2001) 254-275.

－ 47 －

JAEA-Review 2008-054

2.13 Development of spin-polarized radioactive nuclei around 132Sn
for nuclear spectroscopy
Y. Hirayama 1, K. Matsuta 2, M. Mihara2, S.C. Jeong1, H. Miyatake1, T. Hashimoto 3, Y.X. Watanabe1,
N. Imai1, H. Ishiyama1, S. Ichikawa3, T. Ishii3, T. Izumikawa 4, D. Kameda 5, I. Katayama1,
H. Kawakami1, H. Kawamura 6, H. Makii3, S. Mitsuoka3, S. Momota 7, D. Nagae3, D. Nishimura2,
K. Nishio3, T. Otsubo4, A. Osa3, T.K. Sato3, and T. Shimoda2

Spin-polarized radioactive nuclear beam (RNB) is a useful tool to study nuclear structures andelectromagnetic property of materials. For nuclear spectroscopy around the doubly magic nucleus 132Sn at
TRIAC, we have been developing a tilted-foil (TF) technique for production of spin-polarized RNBs. As
the first step in the development of TF technique, we could produce the 5.9±0.5% polarized 8Li(T1/2=838ms) beam [1] at the experiment in Jan. 2007. To establish the TF technique in the region of heavy
nuclei as the next step, we have tried to produce the polarized 123In (T1/2=6.0 sec, Iπ = 9/2+, g =1.220) andBa (T1/2=14.3 sec, Iπ =5/2−, g=0.1772) in the experiments RNB06K02 (spokesperson: Y. Hirayama) and143

RNB06K03 (K. Matsuta), respectively, in Mar. 2008.
123

In and 143Ba nuclei were produced by proton-induced fissions of uranium at JAEA-ISOL, and wereaccelerated up to 178 keV/A by TRIAC. Typical beam intensities of 123In and 143Ba RNBs at the entrance ofthe tilted foils were about 4x103 pps and 2x103 pps, respectively. 123In (143Ba) nuclei passing through thetwenty 3μg/cm2 thick polystyrene foils at the tilt angle 70o were implanted in an InP (BaF2) crystal at atemperature of about 10K (300K), where the magnetic field B0 ~ 0. 5 T was applied to preserve the nuclear
polarization. The nuclear polarization was measured with β-NMR technique.
The finite polarizations of 123In and 143Ba have not been confirmed in these experiments. It is necessary tofurther check the TF system and the stopper material independently. The present TF system could be
examined by applying to TDPAD measurements of short-lived isomers, whose quadrupole moments are
known. It is also possible to search the stopper materials by utilizing the polarized RNBs of In (Ba)isotopes near the stability line, since these polarized RNBs will be produced by projectile-likefragmentation reactions. After these examinations, we will perform the production of polarized In and Ba
isotopes with TF technique.
References[1] Y. Hirayama et al., JAEA-Tokai TANDEM Ann. Rep. 2006, JAEA-Review 2007-046 (2007) 28-29.
1High Energy Accelerator Research Organization (KEK)
Osaka University
3
Japan Atomic Energy Agency (JAEA)
4
Niigata University
5
The Institute of Physical and Chemical Research (RIKEN)
6
Rikkyo University
7
Kochi University of Technology
2－ 48 －

JAEA-Review 2008-054

CHAPTER 3
Nuclear Reaction

3.1

Measurement of quasi-elastic backscattering in 58Ni+124Sn

3.2

Barrier distribution of quasi-elastic backscattering in 86Kr+208Pb

3.3

Effects of nuclear orientation on fission fragment mass distributionsin the reaction of 36S + 238U

3.4

Fusion reaction 82Kr + 140Ce using JAEA recoil mass separator

3.5

R&D for a test of time reversal symmetry experiment using polarized nuclei－ 49 －

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JAEA-Review 2008-054

3. 1

Measurement of quasi-elastic backscattering in 58 Ni+124Sn

Y.X. Watanabe 1, S. Mitsuoka 2, K. Nishio2, S.C. Jeong1, T. Hashimoto2,
Y. Hirayama1, N. Imai1, H. Ishiyama1, H. Miyatake1, and H. Ikezoe2

The fusion excitation functions for the five systems of 40Ca+90,94,96Zr and 48Ca+90,96Zr at near- andsub-barrier energies were measured at the Laboratori Nazionali di Legnaro, and it was reported that the twosystems possessing multi-neutron transfer channels with positive Q-values (40Ca+94,96Zr) have a large
enhancement of cross sections at lower energies with respect to the other systems [1]. This suggests that thepositive Q-value multi-neutron transfer channels enhance the sub-barrier fusion cross sections. In the twosystems of 58 Ni+ 124 Sn and 64 Ni+ 118 Sn which forms the same compound nucleus 182Pt, the former system
has the positive Q-value multi-neutron transfer channels, but the both systems show similar fusion crosssections below the barriers [2]. In the entrance channel of the fusion process, the projectile nucleus getsover a barrier generated by the Coulomb potential and the nuclear potential, and then it is captured by thetarget nucleus. They undergo the non-equilibrium process, forming a compound nucleus or getting apartagain from each other as deep-inelastic scattering or quasi-fission. The entrance barrier may be modified bya tunnel effect, collective excitations and nucleon transfer channels. The positive Q-value multi-neutrontransfer channels are likely to promote the capture cross section which directly enhances the compound
nucleus formation for the systems of 40Ca+94,96Zr. Although the system of 58 Ni+ 124 Sn shows noenhancement of the compound nucleus formation, it is possible that the capture cross section is promotedby the positive Q-value multi-neutron transfer channels, leading to deep-inelastic scattering or quasi-fission,
not to the compound nucleus. In order to investigate a possible effect of the positive Q-value
multi-neutron transfer channels on the capture cross sections, we intended to measure quasi-elastic
backscattering in the two systems of 58 Ni+ 124 Sn and 64 Ni+ 118 Sn.
In FY2007, we performed the measurement for the system of58

Ni+ 124 Sn with the same

experimental setup which we used for the system of 64 Ni+ 118 Sn in FY2006. The 58 Ni beam wasaccelerated by the JAEA tandem accelerator and the superconducting booster linac, and impinged
on the 124 Sn target, which was made on the carbon film (~30 μg/cm2 ) by a sputtering method withthe thickness of ~110 μg/cm2 . The quasi-elastic backscattered particles were detected by four
silicon semiconductor detectors located at angles of 162° and 172° to the beam direction. The
Rutherford scattering was also detected by two silicon semiconductor detectors located at theforward angle of 45°. Tuning the superconducting booster linac, beam energies were altered
between 195 and 245 MeV by 2 MeV step. Correcting the centrifugal potential for each energy andeach angle, the excitation function of the quasi-elastic backscattering at the 42 incident energies
was obtained.

1
2

High Energy Accelerator Research Organization (KEK)
Japan Atomic Energy Agency (JAEA)－ 51 －

JAEA-Review 2008-054

The upper panel of fig. 1 shows the measured differential quasi-elastic cross sections relative to
the Rutherford ones. The lower panel shows the fusion cross sections from ref. [2]. The abscissa
indicates the energy in the center-of-mass system. The data for the system of 64 Ni+ 118 Sn are shiftedto higher energy by the barrier difference (1.09 MeV) between the two systems for comparison,
which was calculated using the Bass potential [3]. Several curves in the lower panel indicate theresults of coupled-channel calculations with the CCFULL code [4]. The quasi-elastic excitation
functions (curves in the upper panel) are deduced by differentiating the products of the calculated
fusion cross sections and the energies. The broken and solid lines indicate the results of thecalculations with collective excitations. They contain one-phonon excitation of the quadrupole
state for Ni and one- and two-phonon excitations of the quadrupole and octupole states for Sn. The
dot-dashed line indicates the result of the calculation for the system of 58 Ni+ 124 Sn containing apair-neutron transfer channel as well as the collective excitations. Although the measured
quasi-elastic excitation function of 58 Ni+ 124 Sn shows larger values than one for the system of64

Ni+ 118 Sn around the energy of 160 MeV, the result of the calculation with a pair-neutron transfer

channel reproduces the 58 Ni+ 124 Sn data qualitatively. The fusion excitation functions show thesimilar situation. This suggests that the multi-neutron transfer channels have no significant effecton the capture cross sections for the system of 58 Ni+ 124 Sn, which is qualitatively explained by the
one transfer channel of a pair of neutrons.

Fig. 1 The upper panel shows the ratio of the differential quasi-elastic scatteringcross sections relative to the Ruthrford ones (dσqel/dσR) and the lower panel shows
the fusion cross sections (σfus) from ref. [2]. Details are discussed in the text.

References[1] A.M. Stafanini et al., Phys. Rev., C76 (2007) 014610.
[2] K.T. Lesko et al., Phys. Rev., C34 (1986) 2155-2164.
[3] R. Bass, Phys. Rev. Lett., 39 (1977) 265-268.
[4] K. Hagino, N. Rowley and A.T. Kruppa, Comp. Phys. Comm., 123 (1999) 143-152.
－ 52 －

JAEA-Review 2008-054

3. 2

Barrier distribution of quasi-elastic backscattering in 86Kr+208Pb
S. Mitsuoka 1, H. Ikezoe1, K. Nishio1, T. Hashimoto1, Y.X. Watanabe 2,
S.C. Jeong2, Y. Hirayama2, N. Imai2, H. Ishiyama2, and H. Miyatake2

We have systematically measured the barrier distributions in 48Ti, 54Cr, 56Fe, 64Ni and 70Zn+208Pb relating to
the Pb-based cold fusion reactions for the production of super-heavy elements Z=104, 106, 108, 110 and
112, respectively [1]. The barrier distributions were derived from the first derivative of the quasi-elastic(QE) backscattering cross sections relative to the Rutherford scattering cross section. The shape of thebarrier distributions was well reproduced by the results of a coupled-channel calculation taking account of
the coupling effects of two phonon excitations of the quadrupole vibration for the projectiles and of theoctupole vibration for the 208Pb target [1,2]. The centroid of the barrier distributions showed a good
agreement with that from the Christensen-Winther (C-W) potential, but showed a deviation from the Bassand several predicted barrier heights by about 3-10 MeV toward the low energy side [1]. Recently, a similar
work on the QE barrier distribution has been measured in the 86Kr+208Pb reaction relating to the cold fusion
for Z=118 [3]. They reported that such deviation was very small except for the C-W potential. Their data
were taken at various detector angles down to 125° in the steps of 5° at five beam energies by using thecyclotron accelerator. Here we measured the QE distribution in the same 86Kr+208Pb reaction by using the
JAEA tandem-booster accelerator.
A 86Kr15+ beam was supplied from an ECR ion source in the high voltage terminal of the tandem accelerator.
A 208Pb target (100 μg/cm2 in thickness, 3 mm in diameter, 99% enriched) with carbon backing (30 μg/cm2)
was bombarded by the 86Kr beam with changing the energy about 30 times in the steps of 1.5 MeV. As
shown in fig. 1, the backward QE scattering was detected by 16 solid state detectors (SSDs) arranged
annularly with respect to the beam axis at the laboratory angles of 172° and 164°. Other SSDs at ±45°
monitored the beam intensity. The barrier distributions
were obtained by taking the first derivative of the QE
excitation function σQE(E) relative to the Rutherford
scattering σR(E) as a function of center-of-mass energy
E, that is -d{σQE(E)/σR(E)}/dE. Detailed analysis is inprogress for QE cross sections where deep-inelastic
scattering should be carefully excluded by considering
the reaction Q-values of inelastic and transfer reaction
channels.
References[1] S. Mitsuoka el al., Phys. Rev. Lett., 99 (2007) 182701.
[2] Z. Muhammad el al., Phys. Rev., C77 (2008) 034604.
[3] S.S. Ntshangase et al., Phys. Lett., B651 (2007) 27-32.
1
2

Japan Atomic Energy Agency (JAEA)
High Energy Accelerator Research Organization (KEK)－ 53 －

Fig. 1 Experimental set up.

JAEA-Review 2008-054

3. 3 Effects of nuclear orientation on fission fragment mass distributionsin the reaction of 36S + 238U
K. Nishio 1, H. Ikezoe1, S. Mitsuoka1, I. Nishinaka1, Y.X Watanabe2,
Y. Nagame1, T. Ohtsuki3, and K. Hirose3

In the production of super-heavy elements based on the 48Ca projectiles and actinide target reactions, themeasured evaporation residue (ER) cross-sections for 48Ca + 238U and 48Ca + 242,244Pu [1,2] have maxima at
bombarding energies close to the barrier for equatorial collisions, suggesting a higher fusion probability at
this orientation. In the case for light projectile 16O, the measured ER cross-sections suggest that fusion
occurs for every colliding angles and is independent of the nuclear orientation [3]. In the reaction usingheavier projectiles 30Si + 238U [4], competition between fusion and quasifission was suggested at the
sub-barrier energy region, whereas no significant fusion hindrance was found at equatorial collisions.
Based on the argument in [5], we expect a symmetric mass
distributions for compound nucleus fission, and an
asymmetric distribution for quasifission. In a reaction
where fusion is influenced by orientation effects, we expect
an increase of asymmetric fission at sub-barrier energies
due to an increase of quasifission at polar collisions. In thepresent work we have measured the fragment-mass
distributions for 36S + 238U in order to study a transition
from quasifission to compound-nucleus fission as functionof the bombarding energy.
The experiment was carried out by using sulfur beams
supplied by the JAEA tandem accelerator. Two fission
fragments

weredetectedincoincidencewithposition-sensitive multi-wire proportional counters. Fission
events after the transfer of full momentum of the projectiles
to the system were separated from those following nucleon
transfer reactions by measuring the emission angles andout-of-plane angles.
Figure 1 shows the dependence of the mass distributions for36

S + 238U on the center-of-mass energy (Ec.m.). At the twohighest energies of 180.0 and 176.0 MeV, the mass
distributions are symmetric. With decreasing bombarding
1

Japan Atomic Energy Agency (JAEA)
2High Energy Accelerator Research Organization (KEK)3
Tohoku University－ 54 －

Fig. 1 Fission fragment mass distribution for36
S + 238U. Center-of-mass energies (Ec.m.)and excitation energies ( E* ) are indicated.

JAEA-Review 2008-054

energy an additional asymmetric mass distribution becomes evident. A remarkable change occurs at
sub-barrier energies of Ec.m.<160.0 MeV, where the distribution becomes dominantly asymmetric withpeaks at AH = 200 and AL = 74.
The variation of the mass distribution with bombarding energy results from the orientation effects of thedeformed target nucleus 238U on the reaction. The potential energy surface for 274Hs in fig. 2, calculated bya modified two center shell-model, shows that the nucleus 274Hs has a fission valley leading to mass
asymmetry around AH / AL ~ 192 / 82 in addition to the one leading to symmetric fission. In this figure, (α,z0 ) values for the polar and equatorial collisions are shown. The z0 value for the polar collisions is larger
than the one for the asymmetric saddle point A, whereas the z0 value for equatorial collisions has smaller z0
values. At deep sub-barrier energy, where only polar collisions lead to nuclear contact, most of thereactions with projectile and target captured inside the Coulomb barrier disintegrate as quasifission by therepulsive Coulomb force through the asymmetric fission valley. The measured mass asymmetry AH / AL ~200 / 74 at sub-barrier region is reasonably reproduced by the calculation. At the higher bombarding energy,
where equatorial collisions dominate, the system has larger probability to form the compound nucleus C
and fissions through over the symmetric saddle point S. The contributions of the two components to thetotal cross-section vary gradually with the beam energy.

Fig. 2 Potential energy surface for 274Hs plotted on the charge distance z0 and mass asymmetry
parameter α. The contact points for polar and equatorial collisions are indicated by p and e.
Symmetric and asymmetric fission paths are found, stating respectively from the saddle points S
and A.
References[1] Yu.Ts. Oganessian, J. Phys., G34 (2007) R165-R242.
[2] Yu.Ts. Oganessian et al., Phys., Rev. C, 70 (2004) 64609.
[3] K. Nishio et al., Phys. Rev. Lett., 93 (2004) 162701.
[4] K. Nishio et al., Eur. Phys., J. A29 (2006) 281-287.
[5] M.G. Itkis et al., Nucl. Phys., A787 (2007) 150c-159c.
－ 55 －

JAEA-Review 2008-054

3. 4

Fusion reaction 82Kr + 140Ce using JAEA recoil mass separator
K. Nishio 1, H. Ikezoe1, S. Mitsuoka1, M. Matsuda1, I. Nishinaka1,
T.K. Sato1, T. Hashimoto1, and Y.X. Watanabe2

Neutron shell at N = 126 plays an important role in the properties of nuclei investigated so far. In the regionof neutron deficient actinide nuclei, the liquid drop model predicts that 222Cm (N=126) has low fission
barrier of only 1.4 MeV, so that the nucleus is unstable against spontaneous fission and the half-life iscalculated to be about 10-12 s. However, in the calculation which takes into account the microscopic
properties of the nucleus, the shell-energy correction at N = 126 forms a deep minimum at the ground stateand creates a fission barrier of about 5 MeV. This results in partial-half life for spontaneous fission of 105
year [1]. This nucleus decays by emitting α particle with half-life of 0.1～10 ms [1,2], long enough to be
detected. For the actinide nuclei with N=126, the isotopes up to uranium (218U) has been produced.
The purpose in this study is to produce neutron-deficient actinide nuclei around N=126 with element
heavier than uranium and investigate the role of the shell on the stability of the nuclei. Firstly, we havestarted the production of a new isotope 220Pu in the fusion-evaporation reaction of 82Kr + 140Ce at the JAEA
tandem facility.
In order to separate the 220Pu from the 82Kr beams the JAEA recoil mass separator was used. Recent
development of ECR ion source at the tandem facility succeeded in the production of high intensity beams,
making such experiments more efficient. We also developed a system to reduce background particles whichpass through the separator, as explained below. We found that most of the scattered particles are generated
when the beams hit the edge of the frame used to support the thin target foil on the rotating disk. The
number of background particle transported to the focal plane is shown in fig. 1(a) obtained in the reactionof 82Kr + 140Ce with the 82Kr energy of 380 MeV. Intensive background particles are generated when the
beam hits the frames (we have two frames ). In order to prevent the scattering of the projectiles at theframes, we developed a beam chopper system synchronized with the target rotation. The location of theframe on the wheel is monitored by a photo-sensor. The signal was fed to the high voltage generator tooperate an electro-static stirer to kick the beams. Figure 1 (b) shows the spectrum of background particles
under the operation of the chopper. With this method, the background rate was suppressed to be 5 % of thevalue before.
We have carried out the experiment 82Kr + 140Ce with suppressed background condition. The 140Ce target
was made by sputtering the Ce metal on a 1.2 μm aluminum foil with the thickness of 400 μg/cm2. The
sputtered material was covered by a carbon layer (20～30μg/cm2) to prevent oxidization. The target wasirradiated by 55 pnA 82Kr beams with the center-of-mass energy 228 MeV at the middle of the Ce target
layer. With totally 29 hour irradiation (net), we did not observed any indication of the production of 220Pu.

1
2

Japan Atomic Energy Agency (JAEA)
High Energy Accelerator Research Organization (KEK)－ 56 －

JAEA-Review 2008-054

The upper limit cross-section was 70 pb, and the value is compared with the fusion-evaporation calculationin fig. 2, where the calculations have uncertainty arising from the estimation of fusion hindrance from thedata obtained in refs. [3] and [4].

Background particles

without chopper
frame

4000

with chopper

140

(a)

(b)

120
100

2000

80
60

60

40

40

20

20

0

0

0

100 200 300 400

0100 200 300 400

Target position

Target position

Fig. 1 Background particles transported to the focal plane of the JAEA recoil mass separator plotted as afunction of the location of the target wheel irradiated by the 82Kr beam.

cross-section (pb)

104

221

Pu

103

220

Pu

102

219

Pu

101
100

210

220

230

240

250

Center-of-mass energy (MeV)
Fig. 2 Cross-sections for Pu isotopes estimated in the reaction 82Kr + 140Ce. The upper limit
cross-sections for 220Pu obtained in this experiment is shown by the arrow.

References[1] H. Koura, private communication.
[2] P. Moller, At. Data and Nucl. Data Table, 66 (1997) 131-343.
[3] K. Nishio et al., Phys. Rev., C63 (2001) 044610.
[4] K. Satou et al., Phys. Rev., C73 (2006) 034609.

－ 57 －

JAEA-Review 2008-054

3. 5 R&D for a test of time reversal symmetry experiment using polarized nuclei
J. Murata 1, T. Akiyama1, M. Hata1, Y. Hirayama2, Y. Ikeda1, T. Ishii3, D. Kameda4, H. Kawamura1,
S. Mitsuoka3, H. Miyatake2, D. Nagae3, K. Ninomiya1, M. Nitta1, E. Seitaibashi1, and T. Toyoda1

Time reversal symmetry is one of the most fundamental symmetries in the nature. This project is aiming totest the time reversal symmetry using polarized 8Li nuclei produced at TRIAC by tilted foil technique. Finalgoal of this project is to examine an existence of transverse polarization of electrons emitted from thepolarized 8Li nuclei in beta decay. For non-zero value of the transverse electron polarization violates thetime reversal symmetry, which is almost held in the standard model, it can be said that this project is aiming
to test the standard model in a highest precision in a nuclear system. We have developed an electron
polarimeter using a drift chamber, and have performed a test experiment using 8Li nuclei at TRIAC in April
2008, confirming its high enough performance as a polarimeter. The experiment was performed from April
14th to 16th, 2008 using 178keV/u 8Li beam in 10-100kpps intensities, produced from 60MeV 7Li primarybeam (~1.3e μ A) from TANDEM accelerator with 13C target via 13C(7Li, 8Li)12C reaction. This report is a
short description about the test experiment.
Cabbibo-Kobayashi-Maskawa (CKM) mechanism, which is consistent with all the observed CP-violating
phenomena in K-meson and B-meson system, predicts a negligible effect on u-d quark systems. On theother hand, numbers of models based on physics beyond the standard model, predict visible size ofCP-violating effects, i.e. T-violating effects in normal nuclear system. Therefore, observation of a non-zero
T-violating effect directly implies the evidence for a new physics beyond the standard model. A triple
vector correlation between nuclear spin, electron spin and momentum is a T-odd variable, therefore,
assuming time reversal symmetry, beta decay rate must not depends on the correlation named R-correlation,
r

σe ⋅

r
JI

×

r
pe
Ee . In the standard model, R is almost zero. If non-zero R-correlation exists, electrons

JI
defined as;
emitted from the polarized nuclei would have non-zero transverse polarization. Therefore, experimental

investigation of time reversal symmetry can be accomplished by the measurement of electron momentum
and its transverse polarization, using polarized beta unstable nuclei [1,2].
Polarized nuclei are illuminated on the surface of solid material. In the present experiment, in order to focus
on the performance test of the polarimeter system, unpolarized 8Li are used. A thin cupper foil with 37mm
diameter, 10 micron thickness is used as the stopper. Electrons are emitted from the stopped nuclei, andthen inject towards the polarimeter, set outside of the vacuum chamber. The polarimeter utilizes thetransverse analyzing power in a Mott scattering of electrons from heavy nuclei. By measuring hitting ratio
between upward and downward scattered electrons, the transverse polarization can be determined.
1

Department of Physics, Rikkyo University
High Energy Accelerator Research Organization (KEK)3Japan Atomic Energy Agency (JAEA)
4The Institute of Physical and Chemical Research (RIKEN)
2－ 58 －

JAEA-Review 2008-054

Fig. 1 [Left] Principle of determining electron transverse polarization by observing up-down asymmetry inbackward scattering angular distribution. [Right] Reconstructed “V-track”s obtained in the TRIAC
experiment using 8Li (Real Data).
On this purpose, our polarimeter is designed to observe not only the tracks of the incident electrons, butalso the second tracks of backward scattered electrons which originate from a thin metal analyzer foil, setbehind the electron tracking detector. Our polarimeter consists of trigger scintillation counters, planer drift
chamber, and the analyzer foil. We have built a planer multi-wire drift chamber and present experiment isaimed to test the performance as a polarimeter at TRIAC, yielding successful determination of the“V-track” events scattered from the thin gold foil (10 micron foil, 300mm x 500mm). Obtained results on
the Mott scattering angular distribution is good agreement with a Mont-Carlo simulation including full
detector simulation.

Fig. 2 [Left] Experimental setup in the TRIAC experiment. [Right] Reconstructed scattering angular
distribution of the Mott scattering electrons, obtained in the TRIAC experiment.
In the next experiment at TRIAC, we are going to take first physics results on R-correlation using fulltracking measurement with minimum systematic errors from background events.

References[1] J. Sromicki et al., Phys. Rev., C 83 (1996) 932-955.
[2] R. Huber et al., Phys. Rev. Lett., 90 (2003) 202301.

－ 59 －

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JAEA-Review 2008-054

CHAPTER 4
Nuclear Chemistry

4.1

Oxidation of divalent nobelium (No) to the trivalent state using
an electrochemistry apparatus

4.2

Adsorption of element 105, Db, on the anion-exchange resin in HF/HNO3 media

4.3

New apparatus AIDA-II for the study of aqueous chemistry of the transactinide elements

4.4

Production of radioactive tracers for chemistry of transactinide elements－ 61 －

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JAEA-Review 2008-054

4. 1

Oxidation of divalent nobelium (No) to the trivalent state using anelectrochemistry apparatus

A. Toyoshima 1, Y. Kasamatsu1, K. Tsukada1, Y. Kitatsuji1, H. Haba2, M. Aasi1, Y. Ishii1, H. Toume1,
K. Akiyama3, K. Ooe4, W. Sato4, A. Shinohara4, and Y. Nagame1

It is interesting and challenging to elucidate oxidation-reduction (redox) properties of the heaviest elementswith atomic numbers Z > 100, such as stable oxidation states and redox potentials in aqueous solutions.
Such redox properties show relative stabilities of the oxidation states, and thus redox studies of the heaviest
elements give us valuable information on binding energy of valence electrons for those elements that would
be influenced by relativistic effects. Redox properties of the heaviest elements are, however, little known
because these need to be studied based on atom-at-a-time chemistry. So far performed were the redox
experiments using chemical oxidizing or reducing agents. These methods are, however, unsuitable for
precise determination of the redox potentials because of the irregular experimental conditions and the slow
kinetics. An electrochemical approach is, therefore, of essential importance to examine the redox propertiesof the heaviest elements. Recently, we have developed a new electrochemical apparatus using aflow-electrolytic column combined with a chromatographic separation technique available for a tracer scale[1]. In this report, we present successful electrochemical oxidation of nobelium (No) in 0.1 M
α-hydroxyisobutyric acid (α-HIB) solution using the apparatus on single-atom scale.
The isotopes 255No (3.1 min) and 162Yb (18.9 min) were produced in the 248Cm(12C,5n) and Gd(12C,xn)
reactions, respectively, at the JAEA tandem accelerator. Ytterbium-162 was used to monitor its elution
behavior as a trivalent ion. Reaction products transported by a He/KCl gas-jet method were deposited on acollection site of a chemical device for 10 min. The products were then dissolved with 0.1 M α-HIB (pH3.9) and subsequently fed into a column working-electrode of the electrochemistry apparatus through a thin
Teflon capillary. The working electrode was made by glassy-carbon fibers packed into a porous Vycor-glass
tube, and the surface of the carbon fibers was chemically modified with a polyelectrolyte material of
Nafion perfluorinated ion-exchange resin. Thus the working electrode serves just as a cation-exchange
column. An electric potential applied to the electrode was adjusted to be 0.2 - 1.2 V versus an Ag-AgClreference electrode using a potentiostat. Details of the electrochemistry apparatus are found in ref. [1]. The
effluents from the working electrode were fractionated into six 180 μL aliquots which were collected on
separate 6 Ta discs. The products adsorbed on the electrode were then stripped with 280 μL of 3 M HCl andthe effluent was collected on another 2 Ta discs. These eight fractions were evaporated to dryness withhelium gas and halogen heat lamps, and were subjected to α-spectrometry equipped with eight 600 mm2
PIPS detectors. After the α-particle measurement, γ-rays of 162Yb were measured with Ge detectors. Elution
behaviour of 81Sr (22.2 min) and 162Yb produced by the Ge(12C,xn) and Gd(12C,xn) reactions, respectively,
1

Japan Atomic Energy Agency (JAEA)The Institute of Physical and Chemical Research (RIKEN)
3Tokyo Metropolitan University
4
Osaka University
2－ 63 －

JAEA-Review 2008-054

was also measured in separate experiments under the same conditions as those of 255No in order to verify
the difference in elution behavior between the divalent (Sr2+) and trivalent (Yb3+) ions.
In fig. 1(a), the elution behavior of 81Sr2+ and 162Yb3+ used as the indicators for the oxidation states isshown by triangles and squares, respectively. Open symbols represent the behavior under the applied
potential of 0.2 V and the closed symbols are of 1.2 V. Independently of the applied potentials, 162Yb3+ waseluted in 0.1 M α-HIB, while 81Sr2+ was stripped with 3 M HCl, showing clear separation of the different
oxidation states under the present conditions. In figs. 1(b) and (c), elution behavior of 255No is shown under
the applied potentials of 0.2 V and 1.2 V, respectively. At the low potential of 0.2 V, 255No was observed
only in 3 M HCl, indicating that No is bound in the most stable divalent state. On the other hand, at thehigher potential of 1.2 V, 255No was unambiguously detected in 0.1 M α-HIB, showing that No exists as a
trivalent ion. These results demonstrate that the electrochemical oxidation of No2+ to No3+ is successfully
performed.
0.5
0.4
0.3

(a)

3.0 M
HCl

0.1 M α-HIB (pH 3.9)
162Yb3+81Sr2+

Eluted radioactivity / a.u.

0.2
0.1
0
0.4
0.3

3.0 M HCl(b) 0.2 V
0.1 M α-HIB (pH 3.9)

0.2

No2+

0.1
0

(c) 1.2 V
0.2

No3+

0.1
0

0

200 400 600 800 1000 1200 1400

Eluted Volume / μL

Fig. 1 (a) Elution behavior of 81Sr2+ (Δ, ▲) and 162Yb3+ (□, ■); open symbols
show the behavior under the applied potential of 0.2 V, while closed symbols
are of 1.2 V. (b) Elution behavior of No2+ (○) under the applied potential of 0.2
V and (c) No3+ (●) under the potential of 1.2 V.

Reference[1] A. Toyoshima et al., Radiochim. Acta, 96 (2008) 323-326.

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JAEA-Review 2008-054

4. 2 Adsorption of element 105, Db, on the anion-exchange resin in HF/HNO3 media
Y. Kasamatsu 1, A. Toyoshima1, M. Asai1, K. Tsukada1, Y. Ishii1, H. Toume1, I. Nishinaka1, T.K. Sato1,
Y. Nagame1, H. Haba 2, H. Kikunaga2, K. Akiyama 3, S. Goto 4, T. Ishikawa4, H. Kudo4, W. Sato 5,
K. Ooe5, T. Kuribayashi5, A. Shinohara5, N. Kinoshita 6, M. Arai6, A. Yokoyama6,
M. Sakama 7, Z. Qin 8, and Ch.E. Düllmann 9

The aqueous phase chemistry of the group-5 elements Nb, Ta, and element 105 (dubnium, Db) has beenstudied by several research groups by chromatographic methods, and the similarity of the chemical
behavior of Db to those of its lighter homologues has been discussed [1-3]. For deeper understanding of thechemical properties of Db, more detailed systematic studies are required. To systematically investigate
fluoride complexation of Db as a function of the fluoride ion concentration and the nitrate ion concentration,
we previously studied the anion-exchange behavior of the homologues Nb, Ta, and also the pseudohomologue Pa in HF/HNO3 solutions by a batch method [4, 5]. Furthermore, we also conducted on-line
anion-exchange experiments with Nb and Ta produced at the JAEA tandem accelerator and confirmed that
distribution coefficients of Nb and Ta obtained by the batch experiments and those by the on-line
experiments agree with each other [6]. In the present work, we performed on-line anion-exchange
experiments with Db together with Ta.
Dubnium-262 was produced in the 248Cm(19F, 5n) reaction at the JAEA tandem accelerator. Tantalum
isotopes were simultaneously produced by using 32 μg/cm2 of 152Gd contained in the 540-μg/cm2 248Cm
target to monitor the elution behavior and chemical yield of Ta during the experiment. The reaction
products were continuously transported by a He/KCl gas-jet system to the collection site of the AIDA
(automated ion-exchange separation apparatus coupled with the detection system for alpha-spectroscopy).
After the collection for 73 s, the products were dissolved in 120 μL of 0.89 M HF/0.3 M HNO3 solution
and were fed onto the column (φ1.0 × 3.5 mm) filled with the anion-exchange resin MCl GEL CA08Y at aflow rate of 1.2 mL/min. The effluent was collected on a tantalum disk as fraction 1, which was followedby the evaporation to dryness with hot helium gas and a halogen heat lamp. The remaining Db and Ta on
the resin were stripped with 150 μL of 0.015 M HF/6 M HNO3. The effluent was collected on another disk
as fraction 2 and evaporated to dryness in the same way. The both disks were automatically transferred tothe α-spectroscopy station of AIDA, where α particles were detected with eight passivated ion-implanted
planar silicon (PIPS) detectors. After the α-particle measurement, some of the samples were subjected to1

Japan Atomic Energy Agency (JAEA)The Institute of Physical and Chemical Research (RIKEN)
3Tokyo Metropolitan University
4
Niigata University
5
Osaka University
6
Kanazawa University
7
University of Tokushima
8
Institute of Modern Physics (IMP)9Gesellschaft fur Schwerionenforschung (GSI)
2－ 65 －

JAEA-Review 2008-054

the γ-ray measurement with Ge detectors to monitor the γ-ray intensity of 169Hf which is a daughter nuclideof 169Ta. The anion-exchange procedure was repeated about 4000 times with AIDA.
Alpha spectra observed in the both fractions are shown in fig. 1. The number of α counts ascribed to the
decay of 34-s 262Db and its daughter 3.9-s 258Lr was 5.6 in fraction 1 and 0.8 in fraction 2. Alpha counting
in the energy region of interest was almost free from interfering events from other product nuclides. In theevaluation of the α counts, a little interfering events and the background from such as electronic noise weresubtracted. The percent adsorption (%ads) is defined by the equation of 100 × A2 / (A1 + A2), where A1 andA2 are radioactivities in the fractions 1 and 2, respectively. The %ads value of Db on the anion-exchange
resin was less than 80% (99% confidence level) under the studied conditions in which 76% of Nb and morethan 99% of Ta adsorb on the resin [6]. It is found that the adsorption of Db on the anion-exchange resin is

Po

212

8785

Lr
258

Db +
262

At

215

8026

214

7687

10

8250~8700

Counts / 10 keV

20Po

considerably weaker than that of Ta in 0.89 M HF/0.3 M HNO3.

Fraction 1

0
20

10
Fraction 2
0
7000

8000

9000

Alpha-particle Energy / keV

10000

Fig. 1 Alpha spectra measured for the fraction 1 and 2.

References[1] M.K. Gober et al., Radiochim. Acta, 57 (1992) 77-84.
[2] H.P. Zimmermann et al., Radiochim. Acta, 60 (1993) 11-16.
[3] W. Paulus et al., Radiochim. Acta, 84 (1999) 69-77.
[4] Y. Kasamatsu et al., J. Nucl. Radiochem. Sci., 8 (2007) 69-72.
[5] Y. Kasamatsu et al., J. Radioanal. Nucl. Chem., in press.
[6] Y. Kasamatsu et al., JAEA-Tokai TANDEM Ann. Rep. 2006, JAEA-Review 2007-046 (2008) 65-66.

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JAEA-Review 2008-054

4. 3 New apparatus AIDA-II for the study of aqueous chemistry of
the transactinide elements
K. Tsukada 1, Y. Kasamatsu1, M. Asai1 A. Toyoshima1, Y. Ishii1, H. Toume1, and Y. Nagame1

In order to carry out chemical experiments on the heaviest elements with single atoms, we developed an
automated rapid ion-exchange separation apparatus based on high performance liquid chromatography(HPLC) coupled to an on-line α-particle detection system, AIDA (Automated Ion-exchange separation
apparatus coupled with the Detection system for Alpha-spectroscopy). AIDA enables us to perform cyclic
discontinuous column chromatographic separations of short-lived nuclides in aqueous solutions andautomated detection of α-particles within a typical cycle of 80 - 110 s. Chemical properties of element 104,
rutherfordium (261Rf: T1/2 = 78 s), have been successfully studied with AIDA in acidic solutions [1].
Aqueous chemistry of element 105, dubnium (Db), is now being performed at JAEA [2]. The nuclide 34-s
262

Db is produced in the 248Cm(19F, 5n) reaction with the cross section of 1.5 nb. This results in the

production rate of about 0.25 atoms per min. To obtain more accurate data with high statistics, we need todevelop a new device to shorten the time for the preparation of α sources. A new apparatus based on acontinuous sample preparation and detection system, i.e., continuous collection and evaporation of effluent,Gas-jet inlet
Pump
Elution curves
Modified ARCA
Micro-columns(40 columns x 2)
Heater2 x 12 PIN-detectors

Effluent

Ta sheets(x 2)

Slit unit
MovingFig. 1 Schematic view of AIDA-II.
1

Japan Atomic Energy Agency (JAEA)－ 67 －

JAEA-Review 2008-054

and successive α-particles measurement, has been developed. Figure 1 shows the schematic view of the
new apparatus AIDA-II. For the HPLC system, we modified the ARCA [3]. As shown in fig. 1, there are
two pairs of sampling and detection systems, each has two sample transport arms on which thin Ta sheets(30 cm long) are placed. Each arm continuously moves into the detection chamber filled with helium gas.
The effluent is continuously collected on this moving Ta sheet and evaporated with halogen heat lamps.
The dried sample is successively going into the α-particle detection chamber where an array of 12
PIN-detectors is installed for each arm. The sample preparation is accomplished within 20 s. Further, fromthe measurement of radioactivities in each detector, we can measure an elution curve of a nuclide for eachcondition. The remaining nuclides in the column are stripped with other solution and collected on anotherTa sheet.

References[1] Y. Nagame et al., Radiochim. Acta, 93 (2005) 519.
[2] Y. Kasamatsu et al., separated paper in this report (ref. contents No. 4.2).
[3] M. Schädel et al., Radiochim. Acta, 48 (1989) 171.

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JAEA-Review 2008-054

4. 4 Production of radioactive tracers for chemistry of transactinide elements
S. Goto 1, T. Ishikawa1, T. Kawasaki1, T. Hasegawa1, H. Kudo1,
K. Tsukada 2, M. Asai2, A. Toyoshima2, and Y. Nagame2

Since a transactinide element has a very short life and its production cross-section is very small, only a very
little quantity — usually one atom — is handled for a chemistry experiment at a time. To investigate thechemical property of such transactinide element, it is necessary that many repetition experiments in termsof a rapid chemistry method are performed until sufficient statistics are obtained. In other words, it takes
very long time to even one experimental condition. Thus, the off-line experiment using a light homologue
will be valid for an efficient on-line experiment. The aim of this work is to produce the non-carrier tracer
for carrying out such off-line chemical experiments.
For the rapid chemistry experiments of Db, the radioactive isotopes 95gNb (T1/2 = 35 d) and 179Ta (T1/2 = 665d) were selected as a tracer because measuring their gamma-ray (or x-ray) is possible and the half life islong enough. The tracers were produced using the 96Zr(p, 2n)95gNb, 179Hf(p, n)179Ta and 180Hf(p, 2n)179Ta
reactions with JAEA tandem accelerator. The natZr foils (130 mg cm–2) and the natHf foils (133 mg cm–2)
covered with aluminum foils were stacked and placed at the end of the R2 beam line. The Zr foils were puton the front of the target stack to make the proton energy optimal to the intended nuclear reactions. The
proton beam energies on the Zr and Hf target were determined to be about 14 MeV and 11 MeV,
respectively, according to the energy loss calculation. The irradiation time was about 17 hours, and theaverage beam current was about 1.7 µA. The irradiated targets were brought to Niigata University after
cooling down the activity of the by-products such as 90gNb (T1/2 = 14.6 h), 92mNb (T1/2 = 10.15 d) , 96Nb
(T1/2 = 23.4 h), and 177Ta (T1/2 = 56.6 h). The activities of 95gNb and 179Ta were 1.3 MBq and 530 kBq,
respectively, after 1 month from the end of bombardment. Those were enough to perform the experiment
for a few months.
Each tracer nuclide was separated from the target material using an anion-exchange method. The tracers
have been used in different experiments to develop newer solvent extraction technique for 5th-groupelements at Niigata University.

1
2

Niigata University
Japan Atomic Energy Agency (JAEA)－ 69 －

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JAEA-Review 2008-054

CHAPTER 5
Nuclear Theory

5.1

Single-particle property of unstable nuclei around N=28 from the spectroscopic factor
calculated with a new shell model interaction

5.2

Analysis of inclusive (K-, K+) reaction with semi-classical distorted wave model

5.3

Hyperon suppression in hadron-quark mixed phase

5.4

Decay modes and limit of existence of nuclei in the superheavy nuclidic region

5.5

Direct and semi-direct capture in the low-energy (n,γ) reactions of neutron-rich Tin isotopes
and its implications for the r-process nucleosynthesis

5.6

Soft-rotator model analysis for medium-heavy nuclei and systematicsof the Hamiltonian parameters－ 71 －

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JAEA-Review 2008-054

5. 1

Single-particle property of unstable nuclei around N=28 from the spectroscopic
factor calculated with a new shell model interaction
Y. Utsuno 1, B.A. Brown2, T. Otsuka3, M. Honma4, and T. Mizusaki5

Spectroscopic factor represents how the single-particle orbit is occupied in a designated orbit. It is thus
quite useful to explore the single-particle structure in nuclei. Recently, the spectroscopic factor of nuclei farfrom the β-stability line has been accessible by using the so-called knockout reaction [1]. It would provide
key information on how the single-particle structure changes driven, for instance, by the spin-isospin
property of the nucleon-nucleon interaction [2]. In the present study, we investigated a possible exotic shellstructure in the neutron-rich region around N=28 by means of probing the spectroscopic factor. The study isbased on a new shell model interaction for the sd-pf shell model space incorporating the shell evolution
mechanism due to the tensor force [3].
The effective interaction used in the present study is constructed as follows. The inner-shell interactions,
i.e., the sd-shell and pf-shell interactions are taken from standard ones: USD [4] for the sd shell and
GXPF1A [5] for the pf shell. Since the cross shell interaction has not been explored in detail before, wedevelop a new one. The tensor part is fixed to be the π+ρ meson-exchange interaction with cutoff at 0.7 fm[3], and the two-body spin-orbit force is taken from the M3Y interaction [6]. We propose a new way toconstruct the central force of high reliability. Adopting a simple Gaussian force whose parameters are
determined so that its monopole interaction becomes as close to that of the GXPF1 interaction as possible,
the central force of the cross shell interaction is calculated. The new interaction successfully reproduces
low-lying levels in K isotopes from N=20 to 28 systematically.
The spectroscopic factor of nuclei in the sd-pf shell is calculated with a new shell model code NuShellX [7].
It enables to reach the J-scheme shell-model dimension up to the order of 107, which is large enough to
calculate low-lying states in this region. One of the authors (B.A.B.) is developing the code to have asimilar user interface to the well-known shell-model code OXBASH [8]. It will thus replace OXBASH in anear future.
Figure 1 compares the distribution of the experimental and calculated spectroscopic factors for a single
proton-hole state in 48Ca. From a good agreement between them, descriptive power of the presentinteraction is confirmed. In particular, we excellently reproduced a characteristic feature that the d5/2 hole
state is distributed over some states in the 3-8 MeV region. We next apply the calculation to thespectroscopic factor for a neutron pickup reaction on 42Si. Figure 2 shows a strong dependence on the1

Japan Atomic Energy Agency (JAEA)
Michigan State University
3
University of Tokyo
4
University of Aizu
5
Senshu University
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JAEA-Review 2008-054

strength of the tensor force. Without the tensor force, the ground state of the N=29 isotope 43Si is 3/2- as
expected from the naïve shell model configuration of a p3/2 neutron on top of the 42Si core. On the other
hand, when the tensor force is included, the ground state is predicted to be 1/2- having a large spectroscopic
factor with regard to the p1/2 orbit. Hence, that spectroscopic factor should be a good measure to probe theexotic shell structure around 42Si caused by the tensor force.

1

2

2

C S(e,e’p)
3/2

1

+

5/2

+

3/2-

1/2-

+

1/2

0

0

-1
0
1

2

CS

1

0

1

2

3

4

5

-1
0
1

1

2

3

4

5

7/2-

5/2-

1
0

0

2

C S(calc.)*0.73

2
0

-1

5
Ex (MeV)Fig. 1 Distribution of the spectroscopic
factor in a proton removal reaction from48
Ca compared between experiment(upper) and the present calculation(lower). For the calculation, all of thespectroscopic factors are quenched by afactor 0.73.

0

1

2

3

4

5

-1

0

1

2

3

4

5

Ex (MeV)Fig. 2 Distribution of the spectroscopic factor in aneutron pickup reaction on 42Si compared between
interactions with tensor (upper) and without tensor force(lower).

References[1] P.G. Hansen and J.A. Tostevin, Ann. Rev. Nucl. Part. Sci., 53 (2003) 219-261.
[2] T. Otsuka et al., Phys. Rev. Lett., 87 (2001) 082502-1-4.
[3] T. Otsuka et al., Phys. Rev. Lett., 95 (2001) 232502-1-4.
[4] B.A. Brown and B.H. Wildenthal, Ann. Rev. Nucl. Part. Sci., 38 (1988) 29-66.
[5] M. Honma et al., Phys. Rev. C, 69 (2004) 034335-1-34.
[6] G. Bertsch et al., Nucl. Phys., A284 (1977) 399-419.
[7] W.D.M. Rae, Home of NuShellX & NuShell (2007), http://knollhouse.org/ (accessed 2008-05-15).
[8] B.A. Brown, A. Etchegoyen and W.D.M. Rae, OXBASH, MSU-NSCL report No. 524 (1988).

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JAEA-Review 2008-054

5. 2 Analysis of inclusive (K-, K+) reaction with semi-classical distorted wave model
S. Hashimoto 1, M. Kohno 2, K. Ogata 3, and M. Kawai3Interactions between baryons play an important role in hadronic many-body systems with strangeness.
Hypernuclear physics has been disclosing characteristic features of the interactions through analyses ofexperimental data on hyperon production reactions, and the Λ-N interaction has been fairly well explored.
However, because of inadequate data the Ξ-N interaction is very ambiguous despite the fact that its
knowledge is the most important for understanding the physics of octet baryons as a probe of thestrangeness S=-2 sector.
The (K-, K+) reaction with production of a Ξ- hyperon is a principal source of information on the
single-particle potential UΞ felt by the Ξ hyperon in the final hypernucleus that reflects the properties of theunderlying Ξ-N interaction. The K+ spectra of the (K-, K+) reaction were measured [1], and the Distorted
Wave Impulse Approximation (DWIA) analyses of the data evaluated the strength of the real part of the
Ξ-nucleus potential to be about -14 MeV. However, the value was not conclusive because of the limited
statistics and resolution of the experiments and several simplifying approximations used in the DWIA
calculations. The former may be resolved in the future, since accurate experimental data of (K-, K+)
reactions will be measured by the Japan Proton Accelerator Research Complex (J-PARC) project.
The data of Iijima et al. [2] were analyzed by Tadokoro et al. [3] or by Nara et al. [4]. The calculation in ref.
[3] was based on DWIA with the Green's function method using a simplifying approximation that thedifferential cross section for the elementary process K-+p -> K++Ξ- was replaced by a constant value
ignoring the variation of the elementary cross section due to the Fermi motion of the target nucleons. The
analysis in ref. [4] was carried out by means of the intra-nuclear cascade (INC) model. The INC model tookaccount of the Fermi motion with an empirical formula of elementary cross sections. In the calculations,however, the asymptotic momenta of the Ξ and K± were used to calculate the matrix element of theelementary process with neglecting the effects of the Ξ- and K±-distorting potentials.
We analyzed the (K-,K+) reaction with Ξ- production by means of the semiclassical distorted wave (SCDW)
model and examined the validity of the assumptions in the previous works. The SCDW model has beensuccessful in quantitatively describing (p, p’x) and (p, nx) inclusive cross sections [5]. In the recent paper[6], the SCDW model was applied to the analysis of the inclusive spectra of the (π-, K+) reaction with ∑formation.

1

Japan Atomic Energy Agency (JAEA)
Kyushu Dental College
3
Kyushu University
2－ 75 －

JAEA-Review 2008-054

Fig. 1 Momentum spectrum of K+ in 12C(K-, K+) at incident momentum pK-=1.65 GeV/c.
In the left panel of fig. 1 we show the result of the SCDW model with VΞ= -20 MeV (solid line) for the
inclusive (K-, K+) momentum, which is compared with the result of the previous DWIA calculation [3](dashed line) and the one-step contribution evaluated with the INC model [4] (dotted line). The KEK data
[2] are shown in the figure. Since the data are average over the emission angles θK+ between 1.7° and 13.6°,
the values calculated with the SCDW and INC models are correspondingly averaged. On the other hand,
the result of ref. [3] corresponds to θK+=0°.The disagreement between the results of the SCDW model and
the Green's function method is due to the difference in the dependence of the spectrum on θK+; the spectrum
calculated with the SCDW model has very strong θK+-dependence which is due to the change of thetwo-body kinematics of the elementary process in the nuclear medium. The result of the SCDW model
calculation is similar to that of the INC calculation. However, the peak positions of the two spectra deviate
from each other, and the deviation is due to neglecting the Ξ potential. The right pane shows thedependence of the SCDW result on the VΞ. One sees that the VΞ-dependence of the angle-averaged
spectrum is not very strong, and one hardly determines the value of VΞ from the present analysis.
In conclusion, it is obvious that the accurate treatment of the kinematics of the elementary process bymeans of the SCDW model is important to analyze the (K-, K+) reaction. The result of this study suggeststhat more accurate evaluation is necessary such as the contribution from multi-step processes.

References[1] P. Khaustov et al., Phys. Rev., C61 (2000) 054603.
[2] T. Iijima et al., Nucl. Phys., A546 (1992) 588-606.
[3] S. Tadokoro, H. Kobayashi, and Y. Akaishi, Phys. Rev., C51 (1995) 2656.
[4] Y. Nara et al., Nucl. Phys., A614 (1997) 433-460.
[5] Y. Watanabe et al., Phys. Rev., C59 (1999) 2136.
[6] M. Kohno et al., Phys. Rev., C74 (2006) 064613.

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JAEA-Review 2008-054

5. 3

Hyperon suppression in hadron-quark mixed phase
T. Maruyama 1, S. Chiba1, T. Tatsumi 2, and H.-J. Schulze 3

It is well known that hyperons appear at several times normal nuclear density and lead to a strong softeningof the equation of state (EOS) with a consequent substantial reduction of the maximum neutron star mass.
Actually the microscopic Brueckner-Hartree-Fock approach gives much lower masses than current
observation values of ~1.5 Msol. On the other hand, the hadron-quark deconfinement transition is believed
to occur in hot and/or high-density matter. Taking EOS of quark matter within the MIT bag model, themaximum mass can increase to the Chandrasekhar limit once the deconfinement transition occurs in
hyperon matter [1,2]. Since the deconfinement transition from hadron to quark phase may occur as afirst-order phase transition, the hadron-quark mixed phase should appear.
The bulk Gibbs calculation of the mixed phase, without the effects of the Coulomb interaction and surface
tension, leads to a broad region of the mixed phase (MP) [3] and large softening of the EOS. However, if
one takes into account the geometrical structures of the mixed phase, one may find that MP is considerably
limited and thereby EOS approaches to the one given by the Maxwell construction (MC) [4]. In this report
we explore the EOS and the structure of the mixed phase during the hyperon-quark transition, properly
taking account of the Gibbs conditions together with the geometrical structure of the MP.
The numerical procedure to determine the EOS and the geometrical structure of the MP is similar to that
explained in detail in ref. [4]. We employ the Wigner-Seitz approximation in which the whole space isdivided into equivalent cells with a given geometrical symmetry like a sphere for three dimension (3D),cylinder for 2D, and slab for 1D. A lump portion made of one phase is embedded in the other phase andthus the quark and hadron phases are separated in each cell. A sharp boundary is assumed between the twophases and the surface energy is taken into account in terms of a surface-tension parameter. The energy
density of the mixed phase is thus written as

ε=

⎤
⎛
1 ⎡
(∇Vc(r )) 2 ⎞⎟σS+⎢ ∫ V H d 3 rε H (r ) + ∫ V Q d 3 rε Q (r ) + ∫ V W d 3 r ⎜⎜ ε e (r ) +
⎥
2
⎟
VW ⎢
π
e
8
⎠
⎝
⎦⎥
⎣

(1)

where the volume of the Wigner-Seitz cell VW is the sum of those of hadron and quark phases VH and VQ, S
the quark-hadron interface area. εH, εQ and εe are energy densities of hadrons, quarks and electrons, which
are r-dependent since they are functions of local densities a(r) (a = n, p, Σ−, Λ, u, d, s, e). The Coulomb
potential VC is obtained by solving the Poisson equation. For a given density B, the optimum
dimensionality of the cell, the cell size RW, the lump size R, and the density profile of each component are
searched for to give the minimum energy density. We employ σ= 40 MeV/fm2 in the present study. To
calculate εH in the hadron phase, we use the nonrelativistic BHF approach [1] based on microscopic NN
1

Japan Atomic Energy Agency (JAEA)
Kyoto University
3
Istituto Nazionale Fisica Nucleare (INFN)
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JAEA-Review 2008-054

and NY potentials that are fitted to scattering phase shifts. Nucleonic three-body forces are included inorder to (slightly) shift the saturation point of purely nucleonic matter to the empirical value. For the quark
phase, we use the MIT bag model with massless u and d quarks and massive s quark with ms = 150 MeV.
We here use the bag constant B=100 MeV/fm3 and the QCD fine structure constant αs = 0 to get the quark
EOS which crosses the hadronic one at an appropriate baryon density.

Maxwell
Gibbs

Fig. 2 EOS of the MP (thick curves) incomparison with pure hadron and quark
phases (thin curves).

Fig. 1 Density profiles and Coulomb potential VC
within a 3D (quark droplet) Wigner-Seitz cell at
ρB = 0.4 fm−3.

Figure 1 illustrates an example of the density profile in a 3D cell. One can see the nonuniform density
distribution of each particle species together with the finite Coulomb potential; charged particle
distributions are rearranged to screen the Coulomb potential. The quark phase is negatively charged, so thatd and s quarks are repelled to the phase boundary, while u quarks gather at the center. The protons in the
hadron phase are attracted by the negatively charged quark phase, while the electrons are repelled.

n

p,e
Σ−
Fig. 3. Particle fractions in the MP by the full calculation (left) and the MC (right).

Figure 2 compares the resulting EOS with that of the pure hadron and quark phases. The thick black curve
indicates the case of the MC, while the colored line indicates the MP starting with a quark droplet structureand ending with a bubble structure. Note that the charge screening effect, combined with the surface
tension, makes the EOS of the MP close to that of the MC. However, the structure and the composition of
the MP are very different from those of the MC, as shown in fig. 3. In particular, a relevant hyperon (Σ−)
fraction is only present in the MC. Non-uniform structure and suppression of hyperons in the mixed phaseshould have some implications on the neutrino transport and cooling of pulsars.
References[1] M. Baldo, G.F. Burgio, and H.-J. Schulze, Phys. Rev., C61 (2000) 055801.
[2] O.E. Nicotra et al., A& A, 451 (2006) 213.
[3] N.K. Glendenning, Phys. Rep., 342 (2001) 393.

[4] T. Maruyama et al., Recent Res. Devel. Phys., 7 (2006) 1.
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JAEA-Review 2008-054

5. 4

Decay modes and limit of existence of nuclei
in the superheavy nuclidic region
H. Koura 1, T. Tachibana2,1, and S. Chiba1

Nucleus is a composite system consisting of protons and neutrons, and approximately 3000 nuclides havebeen identified experimentally. However, the existence of much more nuclides is postulated theoretically.
How far the area of nuclei extends is an essential and important question in nuclear physics.
We have developed an original model based on the macroscopic and mean-field models to describe theglobal feature of nuclear masses, called the KTUY (Koura-Tachibana-Uno-Yamada) nuclear mass model[1]. The standard deviation from known masses is 0.67 MeV, and below 0.4 MeV from some separationenergies.
By using the KTUY model, we have studied decay modes for α-decay, β-decay, proton emission andspontaneous fission ranging from light nuclei to superheavy nuclei. In the previous report [2], we estimateddominant decay modes and pointed out a possibility of existence of next “island of stability” in the regionof superheeavy nuclei along neutron number N=228 in a considered region of N<250 due to the limit ofcalculation. After that work we extend the region of calculated nuclei to the much heavier region.
Figure 1 is a chart of estimated nuclear decay modes with longer lives than one nanosecond. In the heavier
nuclear mass region, a large amount of nuclei placed over N=308 is shown. This is due to the strong
magicity of N=308. The region of nuclei with longer lives than 1ns ends or is disconnected at N≈334. A
solid curve as a fissility line is also drawn in the figure. This represents a macroscopic limit against
spontaneous fission, and the curve and the neutron-drip line, which is shown as a comb-tooth shape here
and determines the border in the neutron-side, is across each other at N≈334. Our calculation by using the
KTUY model seems to be consistent with this macroscopic consideration. This calculation over Z>174 is
not shown in the figure because of the limitation in our β-decay calculation. From the consideration of themacroscopic fissility line, however, the upper region seems to be not so extended or to be vanished quickly.
Figure 2 shows calculated total half-lives. In this calculation we determined the number of nuclei
depending on the half-life range. For example, the total number of nuclei with more than one nanosecond isestimated to be approximately eleven thousands. Some of other cases are shown in table 1.
Table 1. Number of nuclides with a certain half-lives or longer.

1
2

Shorter limit of half lives

1s

1 ms

1 μs

1 ns

Number of nuclei~4,000~8,000~10,000~11,000

Japan Atomic Energy Agency (JAEA)
Waseda University Senior High School－ 79 －

JAEA-Review 2008-054

160

Calculated nuclear decay modes

β-stable nuclei
from KTUY formula354

126228278

113165

Proton number Z

Z=126
120 Z=114

235

U143

472

Z(Z−1)/A=49.76 (fissility line)

80

Sg210

Z=82
208

Pb126

α-decay dom.
β-decay dom.
Spontaneous fission
Proton emission
β-stable nuclei
from KTUY formula
known nucl. (2004)

Z=50
40

256

U164

132

Sn82

N=50
40

N=82

N=184

N=228

120

Calculated total half lives

Z=126
120 Z=114

Proton number Z

80

N=126

160
200
Neutron number N
Fig. 1 Chart of the nuclides with half-lives of one nanosecond or longer.
α-decay, β-decay, proton emission and spontaneous fission are indicated.

160

T1/2 >1 s-3
1 s>T1/2 >10 s-3-6
10 s>T1/2 >10 s-6-9
10 s>T1/2 >10 s
known nucl.(2004)

β-stable nuclei
from KTUY formula

240

N=308
280

320

Dominant decay modes among354

126228278

113165

235

U143

472

164308Z(Z−1)/A=49.76 (fissility line)80

164308

316

316

Sg210

Z=82
208

Pb126

-9

Z=50
40

256

U164

132

Sn82

N=50
40

N=82
80

N=126
120

T1/2>10 s(ns):~11000 nucl.
T1/2>10-6s(μs):~10000 nucl.
-3

T1/2>10 s(ms):~8000 nucl.
T1/2> 1 s:~4000 nucl.
N=184

160
200
Neutron number N

N=228
240

N=308
280

320

Fig. 2 Calculated total half-lives of the nuclides with half-lives of one nanosecond or longer.

References[1] H. Koura, et al., Prog. Theor. Phys., 113 (2005) 305-325.
[2] H. Koura and T. Tachibana, JAEA-Tokai TANDEM Ann. Rep. 2005, JAEA-Review 2006-029 (2006)
67-68.

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JAEA-Review 2008-054

5. 5 Direct and semi-direct capture in the low-energy (n,γ) reactionsof neutron-rich Tin isotopes and its implications
for the r-process nucleosynthesis
S. Chiba 1, H. Koura1, T. Hayakawa1, T. Maruyama1, T. Kawano 2, and T. Kajino 3

The neutron capture reaction rates on neutron-rich unstable isotopes far from the β-stability line are
essential for understanding the rapid neutron capture nucleosynthesis (r-process), which is considered tooccur in supernova explosions. The neutron magic numbers affect the final mass distribution of products in
the r-process, where the capture cross sections have minima. Astronomical observations of metal-deficientstars reported a "universal" abundance distribution of the r-nuclei in a certain mass region but that relative
abundances between different mass regions separated by the neutron magic number N=82 are different[1].
Therefore, an unstable nucleus 132Sn (N=82) is a key for understanding the r-process.
Rauscher et al. presented clearly the role of the direct neutron capture reaction on Tin and Lead isotopes [2].
They have employed three different models to calculate the single-particle energies (SPE), namely,
Hartree-Fock-Bogoliubov model, relativistic mean field theory, and macroscopic-microscopic finite-range
droplet model. Predictions of the direct capture cross sections based on different models sometimes
disagree up to several orders of magnitude, showing a significance of the nuclear structure effect on direct
neutron capture and hence a clear need of a search for single-particle potential (SPP) that can reproduce the
SPE accurately and systematically.
We carried out a systematic calculation of both direct and semi-direct (DSD) cross sections to improve theprediction of the neutron capture reaction rate on the Tin isotopes. The semi-direct process was included
here to calculate the capture cross section up to 20 MeV to cover an energy range wide enough for manyother applications consistently. In the present study, we adopt a single-particle potential that gives a good
reproduction of the known single-particle energies over a wide mass region. We also perform
Hauser-Feshbach (HF) model calculations and consider
whether the inversion of the HF and direct cross sections
occurs or not at the neutron-rich isotopes [3].
We employed Koura-Yamada SPP [4] (KY-SPP). Figure 1
shows neutron single-particle levels in the vicinity of 132Sn.
The single-particle energies above the N=82 gap are obtained
as the neutron separation energy necessary to bring thenucleus from the corresponding single-particle states of 133Sn
to the ground state 132Sn, while those below the N=82 gap are
given as the neutron separation energy from the ground stateof 132Sn to the corresponding single-hole states of 131Sn.
Calculated binding energies are compared to thecorresponding experimental values. The levels calculated
Fig. 1 Observed (left) and calculated
neutron SPEs in the vicinity of 132Sn.

1

Japan Atomic Energy Agency (JAEA)
Los Alamos National Laboratory
3
National Astronomical Observatory of Japan2－ 81 －

JAEA-Review 2008-054

predict somewhat narrower gap at N=82, but the single-particle energies of the unfilled levels are
reproduced with an accuracy of about 300 keV on the average. It is especially important to predict theenergy and presence of 3p3/2 and 3p1/2 states which can couple to the s-wave of the incoming scatteringwave function, that gives a dominant contribution to the low-energy direct capture cross section relevant to
the r-process.
The DSD neutron capture cross sections are calculated for a series of even-even Tin isotopes at 30 keV,which are shown in fig. 2. The HF cross section is decreasing as the mass number increases, and shows adrastic decrease when going from 130Sn to 132Sn. This trend is completely correlated with the values ofneutron separation energies. On the other hand, the DSD cross section decreases only modestly, and it
exceeds the HF cross section at 132Sn. Therefore, we see that the inversion of the HF and DSD cross section
indeed occurs at the border of the N=82 magic for the neutron-rich Tin isotopes (and probably its vicinity).
The gradual decrease of the direct cross sections in our calculation is different from the more-rapid
mass-number dependence of the calculation by Rauscher et al. [2] due, probably, to the stability of thesingle-particle energies calculated by KY-SPP. The cross symbol denotes a result calculated by Rauscher et
al. [2] by using experimental level energies as their best estimate of the direct (n, γ) cross section of 132Sn.
Our result, without adjustment, is in a fair agreement with this value.
We compared the r-process abundance of 132Sn nuclei, by considering the HF (n,γ) rate alone and both the
HF + DSD rates. We notice that the difference in these reaction rate gives rise to a difference of more than afactor of 3 in the initial abundance of 132Sn nuclei as shown in fig. 3, but the difference diminishes as time
passes..

Fig. 2 Calculated DSD and HF cross sections
for a series of even-even Tin isotopes at 30 keV.

Fig. 3 Time-dependence of the abundance
ratio of 132Sn without and with the contributionof DSD process.

References[1] C. Sneden et al., Astrophys. J., 533 (2000) L139-L142.
[2] T. Rauscher et al., Phys. Rev., C 57 (1998) 2031-2039.
[3] S. Chiba et al., Phys. Rev., C 77 (2008) 015809-1-7.
[4] H. Koura and Y. Yamada, Nucl. Phys., A671 (2000) 96-118.

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JAEA-Review 2008-054

5. 6

Soft-rotator model analysis for medium-heavy nuclei
and systematics of the Hamiltonian parameters
2

S. Kunieda 1, S. Chiba1, K. Shibata1, A. Ichihara1, O. Iwamoto1, N. Iwamoto1, and E.Sh. Sukhovitskii

The equilibrium non-axial deformation may exist as a general feature of atomic nuclei [1]. The soft-rotatormodel (SRM) [2] is a phenomenological nuclear model which is designed to describe the low-lying
collective level structures of even-even nuclei in terms of the asymmetric-rotation and vibration picture. In
this study, we tried to estimate a complete SRM Hamiltonian parameter set for a wide range of even-evenmedium-heavy nuclei in order to investigate the isotopic differences and/or systematic behaviors of theparameter values.
The SRM Hamiltonian parameters such as the equilibrium deformation and elasticity constant parameters
were deduced from experimentally known low-lying level structure which involves the ground-state, γ-, β2and β3-bands in the context of the model. We also carried out the SRM coupled-channels (SRM-CC) [2]
optical model analysis for inelastic scattering cross sections of protons in order to predict the equilibrium
quadrupole deformation parameter β20 (and rigid hexadecapole deformation parameter β4 for deformed
nuclei). The global CC optical model potential developed by us [3] was employed in the SRM-CC
calculation. Figures 1 and 2 show typical results in descriptions of the measured data for 152Sm. Those
analyses enabled us to obtain a complete Hamiltonian parameter set for various even-even nuclei such as
56,58

Fe, 60,62,64Ni, 64-70Zn, 70-76Ge, 74-82Se, 86Sr, 96,98,100Mo, 102Ru, 104-110Pd, 106-116Cd, 116-124Sn, 122-130Te,

144,150

Nd, 148-154Sm, 160Gd, 166Dy, 166,168Er, 174,176Yb, 178,180Hf, 182,184W, 192Os, 194Pt, 232Th and 238U.

Fig. 1 (left panel)
Low-lying level structure given by the SRM
analysis which is compared with measured
data for 152Sm.
γ-bandβ3-bandFig. 2 (right panel)
Inelastic proton scattering differential crosssections at 65 MeV which were describedby the SRM-CC optical model calculations,
together with those by the measurement [4]for 152Sm.

β2-band

G. S. band

1
2

Japan Atomic Energy Agency (JAEA)
Joint Institute for Energy and Nuclear Research (Belarus)－ 83 －

JAEA-Review 2008-054

The estimated quadrupole and octupole equilibrium deformation parameters, i.e., β20 and β30 are listed intable 1 for Ge isotopes as an example. We can clearly see a possible shape transitional phenomenon
between 72Ge and 74Ge. It is consistent with the existence of a sub-shell closure N=40. The same
phenomenon is seen between 74Se and 76Se. The effective deformations βeff2 and βeff3 describe the strengthsof exciting 21+ and 31- states, respectively. The SRM-CC results agree with values derived from theexperimental B(E2) and B(E3) data [5,6]. Big differences between the equilibrium and effective
deformations on 70,72Ge are due to their strong vibrational properties.
Table 1. The equilibrium and effective deformations for 70,72,74,76Ge.

Figure 3 shows the deduced quadrupole non-axial equilibrium deformation parameter γ0β20 as a function ofβ20 for all nuclei of our interests. As presented separately in this figure, the obtained results can beclassified into at least three groups. The nuclei which possess (near) magic (sub-)shell tend to exhibit

γ0~30º even if they have large β20 value as illustrated in fig. 3-a). It is interesting that another group is
positioned along with a line which is slightly shifted towered the prolate shape as plotted in fig. 3-b).
Typical deformed heavy nuclei are characterized by γ0β20~0.04 though no regular behavior is seen as
shown in fig. 3-c). Those findings infer that the non-axiality parameter strongly depends on the shellstructure of nuclei.
a)

b)

c)

Fig. 3 The obtained quadrupole non-axial equilibrium deformation parameters as a function of β20.
They can be classified at least into three groups as shown in a), b) and c) separately.
References[1] L. Guo, J.A. Maruhn, and P.-G. Reinhard, Phys. Rev., C76 (2007) 034317, 1-11.
[2] S. Chiba et al., Nucl. Phys., A624 (1997) 305-327.
[3] S. Kunieda et al., J. Nucl. Sci. Technol., 44 (2007) 838-852.
[4] T. Ichihara et al., Phys. Rev., C36 (1987) 1754-1776.
[5] S. Raman, C.W. Nestor, Jr. and P. Tikkanen, At. Data. Nucl. Data. Tables, 78, (2001) 1-128.
[6] T. Kibedi and R.H. Spear, At. Data. Nucl. Data. Tables, 80, (2002) 35-82.
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JAEA-Review 2008-054

CHAPTER 6
Atomic Physics and Solid State Physics

6.1

Coster-Kronig electrons from N3+ Rydberg states producedin high-energy collisions with He

6.2

Charge state distribution of sulfur ions after penetration of C-foil targets (V)

6.3

Diffusion of 8Li short-lived radiotracer in Li ionic conductors of
NaTl-type intermetallic compounds－ 85 －

This is a blank page.

JAEA-Review 2008-054

6. 1

Coster-Kronig electrons from N3+ Rydberg states producedin high-energy collisions with He

K. Kawatsura 1, K. Takahiro1, M. Sataka2, M. Imai3, H. Sugai2, K. Ozaki1, H. Shibata3, and K. Komaki4

High Rydberg states in low-energy highly charged ions are produced by electron capture processes,
especially double electron capture (DEC). Most of the studies on DEC process have been made on He-likeions such as C4+ and O6+ [1,2] and N5+ [3]. Those from dielectronic recombination (DR) processes havebeen measured with modest resolution for Li-like ions such as C3+, F6+, Ne7+ and Ar15+. Coster-Kronig(C-K) electrons from 1s22pnl states were observed from DEC and DR processes. For high-energy collisions
with He, highly excited states are formed mainly by single-electron excitation of metastable 1s22s2p for
Be-like ions such as O4+ [4] and S12+ [5]. We have found with high-resolution measurements that 1s22pnl
states with relatively lower angular momenta are produced, while high angular momenta are produced in
DEC and DR processes. Recently, the DR spectrum for Li-like N4+ 1s22s, which recombines into Be-likeN3+ 1s22pnl (n ≥ 5) has been measured with high resolution using heavy-ion storage-ring facilities [6]. The
experimental DR spectrum is in agreement with the calculations and also with the optical values. It is also
found that high angular momenta are produced in DR processes. In the present study, to compare with the
DR data [6] and previous results obtained from 32 MeV/u O4+ + He [4], we have measured Coster-Kronig
electrons ejected at zero-degree in 21 MeV N3+ + He collisions with high resolution and systematicallyinvestigated high-Rydberg states of Be-like four-electron N and O ions, where the highly excited states areformed by electron excitation/ionization.
The experiments were performed at the tandem accelerator facility at the Japan Atomic Energy Agency(JAEA) of Tokai. The Coster-Kronig electrons ejected at zero degree in the beam direction were measured
using a tandem-type 45° parallel plate electron spectrometer. The primary N3+ ion beams were produced byusing ECRTIS (Super-Nanogan) installed at the high-energy terminal of the tandem accelerator, and thenaccelerated up to 21 MeV for N3+ ions. The projectile N3+ ions penetrated the He gas target under single
collision conditions. The beam currents were 0.3~10 nA and were collected in the Faraday cup placed rightafter the spectrometer. All spectra were normalized to the same gas-cell target pressure and ion charge.
Figure 1 shows zero-degree ejected electron spectrum around the cusp energy region. The observed
electron spectrum was dominated by the so-called cusp peak at around 0.832 keV and a series of C-K
electron peaks was superposed on the low and high energy wings of the cusp, corresponding to thebackward and forward ejected electrons from the moving projectiles, respectively. Figure 2 shows theejected electron spectrum of autoionization lines from N3+ Rydberg states, where energy scale refers to theprojectile rest frame transferred from the laboratory frame as shown in fig. 1. The representative peaks are
1

Kyoto Institute of Technology
Japan Atomic Energy Agency (JAEA)
3
Kyoto University
4
National Center for University Entrance Examinations
2－ 87 －

JAEA-Review 2008-054

assigned to a series of 1s22p(2P)nl -1s22s(2S)εl’ (n = 5-9) C-K transitions as indicated by the vertical bars.
Vertical bars indicate line positions obtained by,
En = ΔE – Q2Ry/n2,(1)where En is the C-K electron energy, n is the principal quantum number, ΔE is the energy difference
between the initial and final states of the ion core configuration, taken from the compiled transition energy
tables, Q is the effective charge of the N4+ 1s22p(2P) ion core (assumed to be +4 for this case), and Ry is the
Rydberg energy (13.606 eV). In this case, ΔE is 10.0 eV for 1s22p(2P). A detailed analysis of the C-K
spectra for N3+ and O4+ ions, and of the electron-excitation process is underway [7].

33+

21 MeV N + He

100
1

1

50

2

2

3

3

0
0.6

0.7

0.8

0.9

1.0

n=5

Intensity(arb.unit)

Intensity (arb.unit)

150

7 8 9 ...

6

3+

21 MeV N + He
tp = 0.832 keV

2

1

0

1.1

0

5

10

15

20

Electron Energy (keV)Electron Energy (eV)Fig. 1 Zero-degree electron spectrum aroundthe cusp energy (t = 0.832 keV) in the collisionsof 21 MeV N3+ + He. Energy scale refers to thelaboratory frame.

Fig. 2 High-resolution Coster-Kronig electron
spectrum ejected at 0o from the moving
projectile in collisions of 21 MeV N3+ + He.
Energy scale refers to the projectile rest frame.

References[1] N. Stolterfoht et al., Phys. Rev. Lett., 57 (1986) 74-77.
[2] F.W. Meyer et al., Phys. Rev. Lett., 60 (1988) 1821-1824.
[3] M. Mack and A. Niehaus, Nucl. Instrum. Methods Phys. Res., B23 (1987) 116-119.
[4] K. Kawatsura et al., Nucl. Instrum. Methods Phys. Res., B205 (2003) 528-532.
[5] M. Sataka et al., Phys. Rev., A65 (2002) 052704 (1-11).
[6] P. Glans et al., Phys. Rev., A64 (2001) 043609 (1-11).
[7] K. Kawatsura et al., submitted to Nucl. Instrum. Methods Phys. Res. B.

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6. 2 Charge state distribution of sulfur ions after penetration of C-foil targets (V)M. Imai 1, M. Sataka 2, K. Nishio2, H. Sugai2, K. Kawatsura 3,
K. Takahiro3, K. Komaki 4, and H. Shibata1

Charge state is one of the most important aspects to study ion-solid interactions. Various interactions, suchas electron capture, ionization and excitation of projectile and/or target electrons, and consequent
phenomena like energy deposition into targets, i.e., stopping of projectile, are closely related with projectile
charge state and its evolution in target. Equilibrium charge state distributions for various collision systems
after passing through gaseous or solid target have been extensively investigated and compiled [1], althoughcharge state distributions somewhat change upon exiting target foil. As has been presented in the previous
annual report [2], we measured the exit charge state distributions for penetrations of 2.0 MeV/u S10+, S11+
and S13+ ions through C-foil targets of 0.9 10 μg/cm2 in thickness and performed calculations by ETACHA
code [3] to succeed in reproducing the experimental results sufficiently, where ETACHA has been
designed for higher energy (>10MeV/u) region [4]. We have also started another simulation for Sq+ ion
fractions, in which electron transfer cross sections σ qq ' are calculated with codes applicable to the present
collision energy [5]. In this report, results of our extensive measurements on thicker targets to observe real
equilibrium charge state distribution for 2.0 MeV/u S ions are presented.
The present experiments were performed at the LIR1-3 beam line of the 20UR Tandem Accelerator Facility.
A beam of 2.0 MeV/u (64 MeV) S7+ ions was provided from the tandem accelerator within 0.1% of energy
accuracy, using a calibrated energy analyzing magnet. A post-stripper C-foil of ~20 μg/cm2 in thickness
was placed after the energy analyzing magnet to produce higher charge state projectile ions. Energy losses
at the post-stripper foil were estimated to be at most 0.7% by our separate measurement of cusp electronenergies with zero-degree electron spectroscopy [6]. The primary S7+ or post-stripped Sq+ (q = 12, 14) ion
beam was directed by a switching magnet to self-support carbon target foil of 54 and 98 μg/cm2 inthickness. The charge state distributions after foil penetration were measured using the heavy ion magnetic
spectrometer ENMA and a position-sensitive gas chamber detector. The vacuum condition inside thespectrometer was maintained below 106 Pa to eliminate background charge exchange collisions withresidual gas, which was confirmed by measurements without target foil.
Measured charge state fractions for 2.0 MeV/u Sq+ (q = 7, 12, 14) ion incidences are shown in fig. 1. The
statistical errors are less than 1% for almost all the points. Typical total error values are estimated as 20%−5
for the smallest fractions around 1.0 ×10 and less than 0.5% for the largest fractions around 0.3.

1

Kyoto University
Japan Atomic Energy Agency (JAEA)
3
Kyoto Institute of Technology
4National Center for University Entrance Examinations
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JAEA-Review 2008-054

1E+0
1E-1

Fraction

1E-2
1E-3
1E-4
1E-5
1E-6

(a) S7+

1E-7
1E+0

16+
15+

Fraction

1E-1

14+

1E-2

13+

1E-3

12+

1E-4

10+

1E-5

9+

11+

8+

1E-6

(b) S12+

7+
6+

1E-7
1E+0

1E-1

Fraction

1E-2
1E-3
1E-4
1E-5
1E-6

(c) S14+

1E-7
0.1

1

10

100

1000

Target Thickness (μg/cm2)
Fig. 1 Charge state evolution for 2.0 MeV/u S7+, S12+ and S14+ projectiles penetrated through C-foiltargets of 0.9, 1.1, 1.5, 2.0, 3.0, 4.7, 6.9, 10, 54 and 98 μg/cm2 in thickness. Charge state evolution fortargets of 0.9 – 10 μg/cm2 has already been presented in the previous annual report [2].

References[1] A.B. Wittkower and H.D. Betz, At. Data Nucl. Data Tables, 5 (1973) 5; K. Shima et al., At. Data Nucl.
Data Tables, 51 (1992) 173; K. Shima et al., Nucl. Instrum. Methods Phys. Res., B33 (1988) 212.
[2] M. Imai et al., JAEA-Tokai TANDEM Ann. Rep. 2006, JAEA-Review 2007-046 (2008) 87-88.
[3] J. P. Rozet et al., J. Phys., B22 (1989) 33; Nucl. Instrum. Methods Phys. Res., B107 (1996) 67.
[4] M. Imai et al., Nucl. Instrum. Methods Phys. Res., B230 (2005) 63.
[5] M. Imai et al., Nucl. Instrum. Methods Phys. Res., B256 (2007) 11.
[6] M. Sataka et al., Phys. Rev. A65 (2002) 052704; M. Imai et al., Nucl. Instrum. Methods, B67 (1992) 142.

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6. 3

Diffusion of 8Li short-lived radiotracer in Li ionic conductors of
NaTl-type intermetallic compounds

H. Sugai 1, M. Sataka1, S. Okayasu1, S. Ichikawa1, K. Nishio1, S. Mitsuoka1, T. Nakanoya1,
A. Osa1, T.K. Sato1, T. Hashimoto1, S.C. Jeong 2, I. Katayama2, H. Kawakami2, Y.X. Watanabe2,
H. Ishiyama2, N. Imai2, Y. Hirayama2, H. Miyatake2, Takanori Hashimoto 3, and M. Yahagi3

Non-destructive and on-line Li diffusion experiments in Li ionic conductors are conducted using theshort-lived α-emitting radiotracer of 8Li. Li-8 decays through β-emission to 8Be with a half lifetime of
0.84s, which immediately breaks up into two α-particles with energies broadly distributed around 1.6MeV
with a full width at half maximum (FWHM) of 0.6MeV. The radiotracers produced as an energetic andpulsed ion beam from TRIAC [1] (Tokai Radioactive Ion Accelerator Complex) are implanted into a
structural defect mediated Li ionic conductor of NaTl-type intermetallic compounds (β-LiGa and β-LiIn).
The experimental time spectra of the yields of α-particles are compared with simulated results and Li
diffusion coefficients in the intermetallic compounds [2] are extracted with an accuracy of ±10%. The
diffusion coefficients obtained for β-LiGa [3] with Li content of 43-54 at.% are discussed in terms of theinteraction between Li-ion and the structural defects in the specimen, compared with the cases of β-LiAland β-LiIn [4].
The crystal structure of β-phase (β-LiAl, β-LiGa and β-LiIn) is NaTl-type (or Zintl phase) [4], which iscomposed of two interpenetrating diamond sublattices such that each atom has eight nearest neighbors: four
like and four unlike atoms. The characteristic defect structure of the compound consists of two types ofdefects at room temperature, i.e., vacancies in the Li sublattice (VLi) and Li antistructure atoms in the Ga
sublattice (LiGa). The concentrations of the point defects, [VLi] and [LiGa], strongly depends on Li content;with increasing the Li content from 43 to 54%, [VLi] decreases from 11.4 to 2.8%, while [LiGa] increases
from 0 to 5.1%. VLi is the dominant defect for the Li-deficient region, LiGa is the dominant defect for theLi-rich one. The coexistence VLi of LiGa is expected to form VLi- LiGa complex defects as reported for thedefect structure of β-LiAl, which would play an important role in reducing the strain energy caused by the
point defects in the real cystal. Especially, almost the same amounts of VLi and LiGa exist around thecontent of 51 at.% Li.
As shown in fig. 1, the Li diffusion coefficients of β-LiGa around the Li content of 48 at.% have maximum.
The results is quite different from those observed for β-LiAl and β-LiIn (the Li-content of β-phase:48-54at.%) [4], although they are iso-structural with the β-LiGa. In the cases of β-LiAl and β-LiIn, the Li
diffusion coefficients, the corresponding diffusion constants and activation energies, decrease
monotonically with increasing the lithium content with a minor modification due to the coexistence of VLi

1

Japan Atomic Energy Agency (JAEA)
High Energy Accelerator Research Organization (KEK)3
Aomori University
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JAEA-Review 2008-054

and LiGa. Since the vacancy concentration in the Li sublatticedecreases with increasing lithium content, this monotonic
behavior can be associated with the Li vacancy. The motionof Li is slightly suppressed or assisted depending on the kindsof anti-site atoms; Li diffusion rather slows down in β-LiAl,
while

becomesratherfasterinβ-LiInaroundthestoichiometric region. Such a slight modification in themonotonic behavior of Li diffusion has suggested thepossibility of an interaction between vacancies and lithium
anti-structure atoms; the interaction must be attractive in
β-LiAl and repulsive in β-LiIn [4]. The difference in theinteractions has been understood by the atomic size effect.
The lithium anti-structure atom, LiAl, in β-LiAl produces
compressional strain (expanded lattice), since the radiusFig. 1 Li-content dependence of the
diffusion coefficients for β-LiGa (Ref. 3),
β-LiIn (Ref. 4) and β-LiAl (Ref. 4).

(0.68Å) for the Li ion in a closed shell configuration is larger
than that (0.50 Å) for the Al ion, while the anti-structure atom, LiIn, in β-LiIn induces dilatational strain(contracted lattice) because of ionic radius (0.8 Å) for In larger than that of the substitutional Li ion. On theother hand, the vacancy, VLi, always produces dilatational strain. On the basis of the atomic size effect, theinteraction between VLi and LiGa in β-LiGa is supposed to be attractive as in β-LiAl, because the radius(0.62 Å) of Ga ion is slightly smaller than that of Li ion. The strength of the interaction can be considered
to be weaker than observed in β-LiAl and β-LiIn, since the radii of the constituent ions are quite close toeach other.
As mentioned in the former paragraph, the Li diffusion around the stoichiometric region is faster than in themost Li-rich region and Li-deficient one, demonstrating that the Li diffusion through the vacancies on the
Li atomic site seems to be strongly promoted by the coexistence of VLi and LiGa. This suggests that theinteraction between VLi and LiGa would be unexpectedly large and repulsive as same as observed in β-LiIn[4]. On the other hand, it is also suggested that the motion of Li ion for the Li-deficient region could bequenched by the formation of the defects complex such as VLi-LiGa-VLi and /or VLi-VLi, since theconcentration of VLi defects is much (almost three times) larger in the Li-deficient side as compared to thecases in β-LiAl and β-LiIn. It should be noted that the number of vacant Li sites in a unit cell volume (8 for
Li and 8 for Ga) is about two for the most Li-deficient β-LiGa, whereas there exist about one vacant Li site
in every two unit cells for the most Li-deficient β-LiAl and β-LiIn [4] by assuming the random distributionof the vacancies over the entire volume.

References[1] Information on http://www.srim.org/[2] S.C. Jeong et al., Nucl. Instrum. Methods Phys. Res., B230 (2005) 596-600.
[3] H. Sugai et al., Defect and Diffusion Forum, 273-276 (2008) 667-672.
[4] J.C. Tarczon et al., Mater. Sci. and Eng., A 101 (1988) 99-108.
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CHAPTER 7
Radiation Effects in Materials

7.1

Character and accumulation effects of ion tracks in UO2 and CeO2
under irradiation with high energy ions

7.2

Evaluation of radiation damage in CeO2 createdby high-density electronic energy deposition

7.3

Evaluation of radiation damage in CeO2 created by Xe-implantation

7.4

Atomic structure of ion tracks in magnesium aluminate spinel irradiatedwith swift heavy ions

7.5

Surface amorphization in single crystalline α-Al2O3 induced by swift heavy ion

7.6

Modifications of atomic structure and optical properties of cuprite
by high-energy ion impact

7.7

Magnetic domains induced by swift heavy ion irradiation in FeRh alloys

7.8

Nanostructural changes of iron disilicides (β-FeSi2) thin films
by high-energy heavy ion irradiation－ 93 －

This is a blank page.

JAEA-Review 2008-054

7. 1

Character and accumulation effects of ion tracks in UO2and CeO2
under irradiation with high energy ionsT. Sonoda 1, N. Ishikawa 2, M. Sataka2, K. Yasunaga 3, M. Kinoshita1, and A. Iwase 4

In order to extend the burnup of LWR fuels, formation and growth mechanism of a crystallographic
re-structuring in the periphery region of high burnup fuel pellets, namely “rim structure” [1] should beclarified. This structure is characterized by the existence of highly dense small sub-grains whose size isapproximately 200 nm, and the accumulation of small pores with average size around 1 μm. The structure
can be formed by the accumulation and mutual interactions of radiation damages, fission products (FPs)and electronic excitations deposited partially by nuclear fissions [2-4]. In order to clarify the character andthe accumulation effects of ion tracks that are formed by highly dense electronic excitation, 210 MeV Xe+14
ions irradiation examinations on UO2 and CeO2 have been done at JAEA-Tokai tandem accelerator facility.
Microstructure evolutions in the irradiated samples are observed in a FE-SEM (JSM-6340F) and a FE-TEM(HF-3000) at CRIEPI. This study was financially supported by the Budget for Nuclear Research of the
Ministry of Education, Culture, Sports, Science and Technology, based on the screening and counseling by
the Atomic Energy Commission.
Figure 1(a) shows the SEM image of irradiation surface of CeO2 under irradiation with 210 MeV Xe+14
ions to a fluence of 2x1015 ions/cm2 at 300 °C. This figure indicates that the drastic change of the surface
condition is occurred under accumulation of ion tracks. In order to observe the change of inner structure ofthis sample, cross-sectional TEM observations have been done. Figure 1 (b) and (c) show the bright field
image and dark field image of the same area of the cross-section, respectively. In these figures, manysmaller grains whose size is around 1~2 μm are observed and they are smaller than the mean grain size of
non-irradiated samples (~6 μm). Moreover, sub-grains whose size is around 0.1 μm are also observed(white allows in fig. 1(c) and (d)). These results suggest that the grain sub-division has been occurred in
CeO2 whose irradiation surface was drastically changed under irradiation with Xe+14 ions. In addition tothese results, the other results such as non-drastic surface changes have been occurred under irradiation
with low energy Xe ions irradiations (~100 dpa) and high energy Xe+14 ions irradiations up to 800°C,
suppose that the accumulation of ion tracks will accelerate the grain sub-divisions.
Figure 2 shows the typical SEM images of irradiated surfaces of UO2 under irradiation with 210 MeV
Xe+14 at 300°C to a fluence of (a) un-irradiated, (b) 1x1013 ions/cm2, (c) 1x1014 ions/cm2, (d) 5x1014
ions/cm2 and (e) 8x1014 ions/cm2. These figures indicate that the irradiation surface is not changed up to
1x1014 ions/cm2, and the drastic change is observed to a fluence between 5x1014 ions/cm2 and 8x1014
ions/cm2. In case of 210 MeV Xe+14 ion irradiation, the fluence to change the irradiation surface of UO2
1

Central Research Institute of Electric Power Industry (CRIEPI)Japan Atomic Energy Agency (JAEA)
3
Kyushu University
4
Osaka Prefecture University2－ 95 －

JAEA-Review 2008-054(~5x1014 ions/cm2) tends to be almost same of CeO2’s. Figure 3 indicates a cross-sectional TEM image of
UO2 under irradiation with 210 MeV Xe+14 at 300°C to a fluence of 5x1014 ions/cm2, and the ion tracks areclearly observed.

(b)

100 nm

(d)

2 μm
(a)

(c)

Fig. 1 SEM and TEM Images in CeO2 under irradiation with 210 MeV Xe+14 to a fluence of 2x1015 ions/cm2 at
300°C, (a) SEM image of irradiation surface, (b) a cross-sectional TEM (bright field) image, (c) a cross-sectional
TEM (dark field) image, (d) the high magnification image of (b).

unirradiated(a)

1×1013 ions/cm2(b)

1×1014 ions/cm2(c)

5×1014 ions/cm2(d)

8×1014 ions/cm2(e)Fig. 2 SEM images of irradiated surface in UO2 under irradiation
with 210 MeV Xe+14 to a fluence of (a) unirradiated, (b) 1x1013
ions/cm2, (c) 1x1014 ions/cm2, (d) 5x1014 ions/cm2, and (e) 8x1014
ions/cm2 at 300°C.

References

Fig. 3 Cross-sectional TEM
images of UO2 underirradiation with 210 MeV
Xe+14 to a fluence of 5x1014
ions/cm2 at 300 °C.

[1] J.O. Barner et al., HBEP-61, 1990, Battelle Pacific Northwest Laboratories.
[2] T. Sonoda et al., Nucl. Instrum. Methods Phys. Res., B191 (2002) 622-628.
[3] T. Sonoda et al., Nucl. Instrum. Methods Phys. Res., B250 (2006) 254-258.
[4] T. Sonoda et al., Nucl. Instrum. Methods Phys. Res., B266 (2008) 2882-2886.

－ 96 －

JAEA-Review 2008-054

7. 2

Evaluation of radiation damage in CeO2 created byhigh-density electronic energy deposition
N. Ishikawa 1

Radiation damage in nuclear fuel in fast breeder reactor can be classified into various types in term of its
defect structure, such as 1) point-like defects created by relatively low energy particle irradiation, 2)
continuous damage region (ion-track) created by high energy particle irradiation, and 3) strain fields
created by accumulation of fission gas. In this study, in order to simulate irradiation damage by high energy
fission fragments in MOX (mixed oxide) fuel, oxide ceramic material (CeO2) with fluorite crystallographic
structure is irradiated with high energy particles using tandem accelerator at Tokai Research andDevelopment Center, Japan Atomic Energy Agency (JAEA-Tokai). The evaluation of radiation damage isdone by X-ray diffraction method, by which quantitative evaluation of radiation damage is possible.
Thin films of CeO2 were prepared on single crystal sapphire substrates by sputtering methods. The film
thickness was about 300 nm. The films were irradiated at various temperatures (room temperature, 400°C
and 800°C) with 120MeV Xe from the tandem accelerator at JAEA-Tokai. Irradiation with 120MeV Xeparticles is to simulate creation of high energy fission fragments. The high temperature irradiation
experiment is performed in order to simulate the damage creation in ceramic fuel at high temperature. In
order to investigate the degradation of crystal structure, X-ray diffraction (XRD) patterns were measured
before and after the irradiation. A sharp XRD peak corresponding to (002) reflection is observed before
irradiation. In this study irradiation-induced change of the (002) peak intensity is investigated.
Figure 1 shows (002) diffraction peaks observed for CeO2 irradiated with 120MeV Xe at 800°C. The
decrease in peak intensity after the irradiation is observed, indicating that radiation damage is induced by
the irradiation even at very high temperature of 800°C. The fluence dependence of the intensity is shown infig. 2. Here, the intensity of (002) peak after the irradiation (I) is normalized by the peak intensity before
irradiation (Io). The change in the normalized intensity for 800°C irradiation is less than that for room
temperature and 400°C irradiation. The decrement of the normalized intensity corresponds to radiation
damage. The figure indicates that the irradiation damage induced at room temperature is nearly the same asthat induced at 400°C, while the irradiation damage induced at 800°C is relatively less than that induced atroom temperature and 400°C. The less damage for 800°C irradiation is probably due to thermalannihilation of radiation damage. Thermal energy corresponding to 400°C is not sufficient to annihilate thedamage, while thermal energy corresponding to 800°C is high enough to annihilate part of radiation
damage.

1Japan Atomic Energy Agency (JAEA)－ 97 －

JAEA-Review 2008-054

120MeV Xe →CeO2 (800℃照射）
800℃

1.2

Intensity (arb. units)

Normalized Intensity, I/I o(002) peak

32

33

34

2θ (degree)

120MeV Xe →CeO2

□ RT
室温照射
○ 400°C
400℃照射● 800℃照射
800°C

1
0.8
0.6
0.4
0.2
0

−0.2 11
10

Fig. 1 X-ray diffraction patterns observed for
CeO2 irradiated with 120MeV Xe at 800°C. The
fluence is, from up to bottom, 0 ions/cm2,
3.0x1011ions/cm2, 1.0x1012ions/cm2, 1.0x1013
ions/cm2, 1.0x1014ions/cm2.

10

12

10

13

2

Fluence (ions/cm )10

14Fig. 2 Intensity of (002) peak normalized by
the peak intensity before irradiation plotted asa function of fluence for CeO2 irradiated with
120MeV Xe at room temperature (RT), 400°C
and 800°C.

Here, the effect of overlapping of ion-tracks is discussed. The coverage of ion-tracks can be defined by
the fraction of ion-tracks which designates the ratio of volume of ion-tracks to the whole sample volume.
The fraction, δ, can be estimated by the Poisson law δ(Φ)=1-exp(-SΦ), which is the function of the fluence,
Φ. Here S is the cross section of ion-tracks. Figure 3 is the fraction plotted as a function of fluence, where
the diameter of the ion-track is assumed as a typical value of 15nm. The figure shows that, after irradiation
up to 3x1012 ions/cm2, the whole sample is covered with ion-tracks.

Further irradiation means further

overlapping of ion-tracks. From the figures shown above, overlapping of ion-track causes severe damage
for room temperature and 400°C irradiation,, while that for 800°C the overlapping results in less damage.

Fraction

1

Fig. 3 The fraction of ion-tracks plottedagainst fluence.
001

Fluence (10

2

12

3

2

ions/cm )－ 98 －

JAEA-Review 2008-054

7. 3

Evaluation of radiation damage in CeO2 created by Xe-implantation
N. Ishikawa 1 and M. Matsuda1

Radiation damage in nuclear fuel in fast breeder reactor can be classified into various types in term of its
defect structure, such as 1) point-like defects created by relatively low energy particle irradiation, 2)
continuous damage region (ion-track) created by high energy particle irradiation, and 3) strain fields
created by accumulation of fission gas. In this study, in order to simulate irradiation damage by
accumulation of high-density fission gas in nuclear ceramic fuel, oxide ceramic material (CeO2) withfluorite crystallographic structure is irradiated with intense beam of gas atoms using nanogan at Tokai
Research and Development Center, Japan Atomic Energy Agency (JAEA-Tokai). Nanogan with electron
cyclotron resonance (ECR) ion source produces intensive positive ion beams from gaseous atoms andmolecules. This is suitable for implanting high-density gaseous atoms into ceramic materials, and is thus
adopted in this study to simulate damage behavior due to high-density accumulation of fission gas. The
evaluation of radiation damage is done by X-ray diffraction method, by which quantitative evaluation ofradiation damage is possible.
Thin films of CeO2 were prepared on single crystal sapphire substrates by sputtering methods. The film
thickness was about 0.1μm. The films were irradiated at room temperature and at 400°C with 140keV Xe7+
from the ECR ion source. From the ion range calculation by SRIM-code, it can be confirmed that all of theirradiated Xe atoms are implanted in the materials. The high temperature irradiation is performed in order
to simulate the damage creation in ceramic fuel at high temperature. In order to investigate the degradationof crystal structure, X-ray diffraction (XRD) patterns were measured before and after the irradiation. A
sharp XRD peak corresponding to (002) reflection is observed before irradiation. In this study
irradiation-induced change of the (002) peak intensity is investigated.
Figure 1(A) shows (002) diffraction peaks observed for CeO2 irradiated with 140keV Xe at room
temperature. In the figure, the fluence values are, from top to bottom, 0 ions/cm2, 1.9x1015ions/cm2,
3.8x1015ions/cm2, 5.5x1015ions/cm2, 1.2x1016ions/cm2, 1.7x1016ions/cm2 and 2.3x1016ions/cm2. Figure 2(B)shows (002) diffraction peaks observed for CeO2 irradiated with 140keV Xe at 400°C. In the figure, thefluence values are, from top to bottom, 0 ions/cm2, 1.9x1015ions/cm2, 5.5x1015ions/cm2, 1.2x1016ions/cm2
and 2.3x1016ions/cm2. Both results indicate that intensity of X-ray diffraction peak decreases by implanting
Xe gas. This means that accumulation of Xe gas increases damage of the ceramic sample.
Figure 2 shows the fluence dependence of X-ray diffraction intensity for CeO2 implanted with 140keV Xe.
The vertical axis is the normalized intensity, I/Io, which is defined by the peak intensity after implantation(I) normalized by the peak intensity before irradiation (Io). From the figure it is found that, for low fluence
region (low gas density region) of the order of 1013-1014 ions/cm2, damage is very small. However, for high1Japan Atomic Energy Agency (JAEA)－ 99 －

JAEA-Review 2008-054

fluence region (high gas density region) of the order of 1016 ions/cm2, damage increases as increasing
fluence. From the figure, there is no difference (within the experimental error) in damage between CeO2
implanted at room temperature and that implanted at 400°C. The damage recovery due to thermal energy
corresponding to 400°C is found to be negligible.
Part of the present study is the result of “Research of highly accurate evaluation of radiation damage inadvanced nuclear reactor fuel ceramics” entrusted to “Japan Atomic Energy Agency” by the Ministry of
Education, Culture, Sports, Science and Technology of Japan (MEXT).

(002) peak(002) peakIntensity (arb. units)

140keV Xe →CeO2 (400℃照射）

Intensity (arb. units)

140keV Xe →CeO2 (室温照射）

(A)

32

33

34

2θ (degree)

(B)

32

33

2θ (degree)

34

Fig. 1 X-ray diffraction peaks for CeO2 thin films implanted with 140keV Xe at room
temperature (A) and at 400°C (B). X-ray diffraction pattern for unimplanted sample is also
shown in the same figure. The fluence is designated in the text.

2

Normalized Intensity, I/I o

Room temp.
● 室温照射○ 高温照射(400℃)
400°C

1

0

13

10

14

10

10

15

2

10

16

Fluence (cm )Fig. 2 Normalized intensity of X-ray diffraction peak plotted against fluence for CeO2 implantedwith 140keV Xe at room temperature (closed circles) and at 400°C (open circles).

－ 100 －

JAEA-Review 2008-054

7. 4

Atomic structure of ion tracks in magnesium aluminate spinel irradiatedwith swift heavy ions
K. Yasuda 1, T. Yamamoto1, S. Kawasoe1, M. Eto1, S. Matsumura1, and N. Ishikawa 2

Numerous investigations of radiation effects have shown that magnesium aluminate spinel, MgAl2O4, ishighly resistant to radiation damage caused by energetic particles, such as electrons, ions and neutrons.
MgAl2O4 is, therefore, a promising candidate for the host of inert matrix fuels in light water reactors andthe transmutation target for minor actinides and/or long life fission products. We have investigated radiation
response of MgAl2O4 under a variety of radiation environments [1,2], including swift heavy ion irradiation,with which one can simulate the radiation damage caused by fission fragments.
Atomic resolution transmission electron microscopy (TEM) observations and analyses have been
undertaken on single crystals of MgO·1.1Al2O3. Swift heavy ions of 200 MeV Xe ions and 350 MeV Au
ions were irradiated at the Tandem Accelerator Facility of JAEA-Tokai at an ambient temperature to
fluence of ranging from 1x1015 to 1x1017 ions/m2. The irradiated specimens were prepared for electrontransparent thin foils with the cross sectional technique, which allows us to observe/analyze irradiatedspecimens as a function of the penetrating depth of incident ions. TEM techniques, such as high resolution(HR) and bright-field (BF) imaging, high angular resolution electron channeling spectroscopy (HARECXS),
were utilized for the evaluation of the atomic structure of ion tracks.
Figure 1 (a) shows a BF image of the cross section specimen. Continuous traces of ion tracks are seen as
diffraction contrast up to a depth of 11 μm, which corresponds to (dE/dx)e=12 keV/nm. Elastic
displacement damage induced by 350 MeV Au ions with a fluence of 5x1015 ions/m2 is estimated to be
1x10-4 dpa from SRIM simulation at a depth of 11 μm. The cation disordering observed in the present study
is, therefore, due to the high density of the electronic excitation. Figure 1 (b)-(d) are HARECXS profiles of
MgO⋅1.1Al2O3 obtained from the unirradiated specimen (b), and those obtained from the cross section
specimen shown in fig.1 (a) at a depth of 2 μm (c) and 8 μm (d), in which normalized x-ray intensity isplotted as a function of incident electron-beam direction in k/g400, where k refers to the intersection of theEwald sphere with the [001] zone axis along 400 systematic reflections. Figure 1 shows that the
HARECXS profiles obtained from the irradiated region differ from those of unirradiated specimens. Thechange is seen more distinctly for the profile obtained at 2 μm than that at 8 μm, indicating greater
disordering with higher values of (dE/dx)e. Those HARECXS profiles were analyzed to obtain the size ofdisordered zone induced by one incident ion [3]. Figure 2 shows the size of disordered region as a functionof (dE/dx)e. The disordered region is formed with a value of (dE/dx)e higher than around 10 keV/nm, andthat it increases with (dE/dx)e, which provides useful information for the evaluation of disordered zone
induced by fission fragments.

1
2

Kyushu University
Japan Atomic Energy Agency (JAEA)－ 101 －

JAEA-Review 2008-054(a)Fig. 1 BF cross section view of MgO·1.1Al2O3 (a) irradiated at 300 K with 350 MeV Au ions to a fluenceof 5x1015 ions/m2, and HARECXS profiles taken from an unirradiated specimen (b), and from a depth of
2 μm (c) and 8 μm (d) of the irradiated specimen. Characteristic x-ray intensities of Al-K, Mg-K and O-K
signals normalized by the those under the kinematic condition are plotted against k/g400.
20.0
Al
Mg

Diameter (nm)15.0

Fig. 2 Diameter of the disordered region induced by
one 350 MeV Au ion in MgO·1.1Al2O3 as a functionof electronic stopping power, (dE/dx)e. The diameters
were evaluated from analysis of HARECXS profiles
under the assumption that the disordered region is
fully disordered.

10.0

5.0

0.0

0

10

20

30

40

Electronic stopping power (keV/nm)

The present study includes the result of ‘Study on radiation damage in oxide ceramics for the transmutationof long life radio isotopes’ entrusted to Kyushu University by the Ministry of Education, Culture, Sports,
Science and Technology of Japan (MEXT).

References[1] K. Yasuda et al., Defect and Diffusion Forum, 206-207 (2002) 53-74.
[2] K. Yasuda et al., Nucl. Instrum. Methods. Phys. Res., B250 (2006) 238-244.
[3] K. Yasuda et al., Nucl. Instrum. Methods. Phys. Res., B266 (2008) 2834-2841.

－ 102 －

JAEA-Review 2008-054

7. 5

Surface amorphization in single crystalline α-Al2O3 inducedby swift heavy ion
N. Okubo 1, T. Nakazawa1, M. Sataka1, and S. Jitsukawa1

Aluminum oxide (α-Al2O3) is expected as functional materials in a field of nuclear energy e.g. an
insulating material, window used for plasma diagnosis in a fusion reactor and an inert matrix material ofgeological disposal of high level radioactive waste. Recently, amorphization in ceramics such as α-Al2O3,
which affects the physical and mechanical properties, is attracted as a phenomenon induced by swift heavy
ion irradiations [1]. In previous studies, we reported that amorphous phase was caused in polycrystalline
aluminum oxide by ion irradiation with high-density electronic energy depositions (Se), although lattice
structure of aluminum oxide is stable against nuclear energy depositions (Sn) [2]. The amorphization
behaviors caused by high-density Se indicated dependences on the specimen depth and grain orientation
around the amorphized-crystalline region. Detailed mechanism of amorphization induced by high energy
ion irradiation has not been clearly understood.
Single crystalline α-Al2O3 specimens with (0001) surface were irradiated with several energies of Xe ionsat ambient temperature, by using the Tandem Accelerator of JAEA. The irradiation energy was from about
160 to 70 MeV by using aluminum foil energy degrader. The specimens used were 10 x 10 mm2 plates with
0.5 mm thickness. The fluences were in the range of from 1.0 x 1013 to 1.0 x 1015 ions/cm2. In the case of
160 MeV, the projected range (Rp) of the Xe ions in the α-Al2O3 was calculated to be 10.7 μm with the
SRIM2000 code [3]. The electronic energy deposition (Se) and nuclear energy deposition (Sn) at the surface
were also calculated to be 24.5 keV/nm and 0.1 keV/nm, respectively. Cross sectional transmission electron
microscope (TEM) observation was conducted after normal focused ion beam sample making process,where 30 keV-Ga+ was used for sputtering and specimen was deposited by platinum, carbon and tungsten toprotect surface and suppress the charge up.
In previous studies, by inferring the result of XRD measurements, the amorphization was considered totake place above the fluence of 1.0 x 1014 ions/cm2 in the case of 160 MeV-Xe ion irradiation [4]. Then, the
α-Al2O3 specimens irradiated at 3.5 x 1014 ions/cm2 was observed by TEM in order to confirm the crosssectional structure. The cross sectional TEM images of region between surface and 3 μm depth and highmagnitude image, which is expanded from inset as a doted rectangular, are shown in fig.1 (1) and (2),respectively. In fig.1 (1), obvious boundary is observed around 800 nm depth. The crystal structure ofsurface region above the boundary was identified to be amorphous and deeper region to be single crystal byelectron diffraction patterns. In fig. 1 (2), distinct ion tracks induced by passing of high energy particles arevertically observed in the region of single crystal. This result indicates that amorphization could be causedby overlapping of ion tracks. The amorhization depth of 800 nm is rather short from the case ofpolycrystalline aluminum oxide [2] in spite of almost same Se and Sn. This difference implies that1

Japan Atomic Energy Agency (JAEA)－ 103 －

JAEA-Review 2008-054

amorhization induced by high energy ion irradiation depends on crystal direction.
In summery, cross sectional TEM measurements demonstrated that amorphization was appeared in surface
region with high Se in single crystalline α-Al2O3 irradiated by swift heavy ions above the fluence expectedfrom XRD measurements. Ion track formation, which could cause amorhization by its overlapping, wasSingle Crystal

Amorphous

Surfaceobserved in depth of crystalline region.

(1)

(2)

Fig. 1 Cross sectional TEM images of Al2O3 specimens irradiated by 160 MeV Xe ions.
Total fluence was 3.5 × 1014 ions/cm2.

References[1] G. Szenes, J. Nucl. Mater., 336 (2005) 81-89.
[2] T. Aruga et al., Nucl. Instrum. Methods Phys. Res., B166-167 (2000) 913-919.
[3] J.F. Ziegler, J.P. Biersack, and U. Littmark, The Stopping and Range of Ions in Solids, (Pergamon Press,
New York, 1985), Chap 8.
[4] N. Okubo et al., JAERI TANDEM Ann. Rep. 2004, JAEA-Review 2005-004 (2006) 90-91.

－ 104 －

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7. 6

Modifications of atomic structure and optical properties of cuprite
by high-energy ion impact
N. Matsunami 1, M. Sataka 2, S. Okayasu2, N. Ishikawa2,
M. Tazawa 3, and H. Kakiuchida3

We have investigated high-energy ion irradiation effects on atomic structure and optical properties of cuprite(Cu2O). Cuprite is known as a p-type semiconductor with bandgap of ~2 eV [1-3]. The present study is a
step towards a study of doped-cuprite and comparison with ion irradiation effects on n-type semiconductors
such as ZnO [4,5]. Furthermore, the band-gap dependence of the electronic sputtering is of interest [6].
Cu2O films were prepared on MgO-substrates at 700 ºC by using an RF-magnetron-sputter-deposition(off-axis) method with a Cu disk target of 99.99 % purity in Ar and O2 gas (total pressure was ~10 Pa andthe O2 flow rate was approximately one-tenth of Ar) [7]. By means of Rutherford backscattering
spectroscopy (RBS), the film thickness and composition are evaluated to be ~100 nm and nearlystoichiometric, using the stopping power in ref. [8] and film density of 5.0x1022 Cu cm-3 (6.0 gcm-3). X-ray
diffraction (XRD) and optical absorption measurements were performed before and after high-energy
heavy ion irradiation. Sputtering yields were obtained using the carbon-foil collector method [7].
XRD shows that the film has (111) preferential orientation of cubic structure. For 100 MeV Xe and 90 MeV
Ni ion irradiation up to 1x1013cm-2, the diffraction intensity and the lattice constant decrease with the ion
fluence, indicating disordering of the crystal structure (see table 1). It is found that the disordering depends
on the electronic stopping power more strongly than the electronic sputtering yields described below, andthat the change in lattice constant does much weaker.
No appreciable change in the optical absorption was observed under 100MeV Xe ion irradiation at
3x1012cm-2. It also appears that the bandgap (2.54 eV) is unchanged under the ion irradiation as shown infig. 1, in contrast with the increase in the bandgap of Al-doped ZnO [5]. Here, the wavelength calibration
was made (the spectra and bandgap slightly differ from those in ref. [7]).
Preliminary results of the electronic sputtering are given in table 1 together with the electronic and nuclear
stopping powers, and the calculated sputtering yields Yc based on the elastic collisions. The measured
sputtering yields Y are much larger than Yc and this confirms that the electronic sputtering plays a dominantrole. It is noticed that the sputtering yields by 100 MeV Xe and 90 MeV Ni differ by a factor of ~4, while
the decease of the XRD intensity is much more pronounced. This may indicate that the radiation effects inthe film are much more effective than near the surface-region. The electronic sputtering yield isinterpolated as 11 at the electronic stopping power of 15 keV/nm and this is somewhat larger than theestimated value of 5 at Eg=2.54 [6]. The discrepancy is under investigation, considering a problem inbandgap determination (oscillation seen in fig. 1), disordering effect mentioned above, modification of thesuggested bandgap dependence of the electronic sputtering yield [6] etc.

1

Nagoya University
Japan Atomic Energy Agency (JAEA)
3
National Institute of Advanced Industrial Science and Technology (AIST)
2－ 105 －

JAEA-Review 2008-054

Table 1. Electronic (Se) and nuclear (Sn) stopping powers in Cu2O (keV/nm), XRD intensity (IXRD)
normalized to that of unirradiated, lattice constant change (Δa) in % at 6x1012 cm-2,
sputtering yield Y, calculated yield Yc based on the elastic collision cascade and Y/ Yc.

20

Ions

Se

Sn

IXRD

Δa

Y

Yc

Y/ Yc

90 MeV Ni
100 MeV Xe
200 MeV Xe

14.7
22.0
26.4

0.032
0.20
0.114

0.95
0.5

-0.8
-1.1

10
38
48

0.21
1.3
0.75

48
29
64

100 MeV Xe

3x10 cm20(a)
Cu O/MgO unirrad.

(b)
12

-2

(ABSORBANCE*E)^2(ABSORBANCE*E)^2

2

10

E

0

2.2

2.4

10

E

g

g

2.6

2.8

3

0

PHOTON ENERGY (eV)

2.2

2.4
2.6
2.8
3
PHOTON ENERGY (eV)Fig. 1 (a) Square of absorbance times photon energy E versus photon energy illustrating the bandgap (indicatedby the vertical arrow) for as-deposited film. The dotted line is the least square fit to the data in the photon
energy of 2.6-2.7 eV. (b) Similar to Fig. 1(a) except for irradiated film with 100 MeV Xe ions at 3x1012 cm-2.

References[1] A. Roos and B. Karlsson, Solar Energy Mater., 7 (1983) 467-480.
[2] J. Ghijsen et al., Phys. Rev., B38 (1988) 11322-11330.
[3] M.T.S. Nair et al., Appl. Surf. Sci., 150 (1999) 143-151.
[4] H. Sugai et al., Nucl. Instrum. Methods Phys. Res., B250 (2006) 291-294.
[5] O. Fukuoka et al., Nucl. Instrum. Methods Phys. Res., B250 (2006) 295-299.
[6] N. Matsunami et al., Nucl. Instrum. Methods Phys. Res., B256 (2007) 333-336.
[7] N. Matsunami et al., Nucl. Instrum. Methods Phys. Res., B266 (2008) 2986-2989.
[8] J.F. Ziegler, J.P. Biersack, and U. Littmark, The Stopping and Range of Ions in Matter, Pergamon Press,
New York (1985).

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7. 7

Magnetic domains induced by swift heavy ion irradiation in FeRh alloys
A. Iwase 1, Y. Zushi1, N. Fujita1, T. Matsui1, F. Hori1, N. Ishikawa 2, and S. Seki3

Recently, we have reported that swift heavy ion irradiation induces ferromagnetic state in Fe-50at.% Rhalloys at low temperatures[1-4]. Although the origin of the irradiation-induced ferromagnetism in FeRhalloy has been gradually clarified, magnetic domain structure for the irradiated FeRh alloys has never beenreported. In this report, we show the domain structure of the ion-irradiated FeRh alloys.
Alloys of Fe-50 at.%Rh were irradiated with 200 MeV Xe ions by using a tandem accelerator at
JAEA-Tokai. The ion-fluences were 2x1012, 5x1012, 1x1013 and 5x1013/cm2. After the irradiations, magnetic
domain structures at the surface of the irradiated samples were observed by using a magnetic force
microscope (MFM) at room temperature.
The result of the MFM observation is shown in fig. 1. In the unirradiated sample, no obvious domain
structure can be seen in the scanned area (25 μm x 25 μm ). In the irradiated samples, the dark and brightcontrasts are observed in the MFM image, which indicate the existence of small magnetic domains in thescanned area. With increasing the ion-fluence, the magnetic domain structures transform from amonochromatic structure on a scale of 5 μm into segmentalized ones on a scale of less than 1 μm. The
magnetic domain structures reveal a fractal-like development with increasing ion-fluence.
The present observation can be explained as follows; the energy parameter (e.g., exchange energy,
magnetostatic energy, magnetocrystalline energy and so on) at the surface are varied by theirradiation-induced local fluctuations of composition and/or strains, which contribute to the development of
the fractal-like domain structures.

References[1] M. Fukuzumi et al., Nucl. Instrum. Methods Phys. Res., B230 (2005) 269-273.
[2] M. Fukuzumi et al., Nucl. Instrum. Methods Phys. Res., B245 (2006) 161-165.
[3] A. Iwase et al., Nucl. Instrum. Methods Phys. Res., B 256 (2007) 429-433.
[4] Y. Zushi et al., Nucl. Instrum. Methods Phys. Res., B 256 (2007) 434-437.

1

Osaka Prefecture University
Japan Atomic Energy Agency (JAEA)
3
Osaka University2－ 107 －

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(a)

(b)

5μm

(c)

(d)

(e)

Fig. 1 MFM images at room temperature for (a) unirradiated Fe-50at.% Rh
and those irradiated to the ion-fluence of (b) 2x1012, (c) 5x1012, (d)1x1013/cm2 and (e) 5x1013cm-2. The scanned area is 25μm x 25μm.

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7. 8

Nanostructural changes of iron disilicides (β-FeSi2)
thin films by high-energy heavy ion irradiation
M. Sasase 1 and S. Okayasu 2

β-FeSi2 was irradiated by various ions with a fluence of 1.0 x 1012 ion/cm2 at room temperature using theTandem accelerator. The size of the columnar defects as a function of the deposited energy (Se) has been
investigated. The present experiments shows that the size of the columnar defects depends on the Se into
the specimens. The deposited energy contributed to the columnar defects formation.
Iron disilicide (β-FeSi2) is one of the candidates of compound semiconductor, which contains harmless
elements to the human bodies, natural resources and the environment [1]. Another attractive feature of
β-FeSi2 is transformation to the metal phase α-FeSi2 when heated above 1246 K. Since the bulk α-FeSi2
has electric resistivity as low as 2.5 x 10-4 Ω cm, one may consider if a small part of β-FeSi2 can betransformed into α-FeSi2 selectively, it can be used as the electrode of a β-FeSi2 based device.
When high-energy heavy ions are irradiated into materials, most of their energies are dissipated throughan electronic excitation [2]. This leads to strong localization of the dissipated energy along the projectile
path. The density of energy deposition is high enough, compared with bond or displacement energy of
the target materials, so that nanostructural changes take place such as amorphization and phase transition
etc. We attempted to perform phase transition from β-FeSi2 into other phase by the high-energy heavy ion
irradiation.
The specimens used in this study were β-FeSi2 films fabricated with the ion beam sputter deposition
method by depositing Fe on Si(100) substrates at certain temperatures [3]. The specimens were irradiatedby 180 MeV Fe11+, 200 MeV Xe14+ and 240 MeV Au24+ ions at room temperature with a fluence of 1.0 x
1012 ions/cm2 using the Tandem accelerator at Japan Atomic Energy Agency (JAEA). The projected
ranges and deposited energies, Se, through the electronic excitation process of these ions in
β-FeSi2/Si(100) are estimated by using the TRIM code calculations [4]. Cross sectional observations
were performed with β-FeSi2/Si(100) by using a transmission electron microscope (TEM, JEOL
JEM-3000F) with a field emission gun operated at 300 keV.
If the phase transition of β-FeSi2 to α phase takes place by the high-energy heavy ion irradiation, it isexpected that nanostructural changes are observed in TEM images. Typical defect nanostructures of
β-FeSi2 thin films irradiated with 240 MeV Au24+ ions are shown as a TEM image in fig. 1. The lines areobserved in this image along the direction perpendicular to the a-axis of β-FeSi2. These lines can beinterpreting as the columnar defects from the higher magnification images. The arrows indicate thecolumnar defect produced by the ion passing along this direction. The amorphization of the damaged
1
2

The Wakasa-wan Energy Research Center (WERC)
Japan Atomic Energy Agency (JAEA)－ 109 －

JAEA-Review 2008-054

area is clearly visible in the samples.

Table 1. The relationship between irradiation
condition and diameter of columnar defects.

Fig. 1 Columnar defects introduced with 240 MeV
Au24+ in β-FeSi2 thin films.

From these TEM micrographs, the size of each columnar defect was estimated. The most probablediameter of the columnar defects was 2 nm for 180 MeV Fe11+ ion irradiation, while 4 nm for 200 MeV
Xe14+ and 6 nm for 240 MeV Au24+ irradiation, respectively. At these experimental conditions, thedeposited energies Se were calculated to be 12.3 – 34 keV/nm, corresponding to 180 Fe11+ – 240 MeV
Au24+ irradiation. These values are listed in table 1 for each ion irradiation condition. The diameter of thecolumnar defects becomes larger with the energy of irradiated heavy ions. This tendency shows that 240
MeV Au24+ ions cause more severe lattice damage compared with 180 MeV Fe11+ and 200 MeV Xe14+ ion
irradiation.
It can be considered that the diameter of the columnar defects depends both on the atomic number and on
the energy of irradiated ions, which is strongly correlated to Se, from a previous study [5]. As listed intable 1, the size of the columnar defects increases with Se. Therefore, defect formation takes place withthermal spike due to the energy dissipation through electron excitation.
Although the phase transition of β-FeSi2 to α phase is not confirmed yet, our results showed thestructural change by high energy heavy ion irradiation. We will intend to observe the microstructure ofdefects and phase transitions in the irradiated films precisely by using both high resolution TEM andmicro-diffraction.
References[1] K. Yamaguchi and K. Mizushima, Phys. Rev. Lett., 86 (2001) 6006-6009.
[2] M. Toulemonde, S. Bouffard, and F. Studer, Nucl. Instrum. Methods Phys. Res., B91 (1994) 108-123.
[3] M. Sasase et al., Thin Solid Films, 401 (2001) 73-76.
[4] J.F. Ziegler, Handbook of Stopping Cross Section for Energetic Ions in All Elements, Pergamon Press,
New York (1980).
[5] Y. Zhu et al., Phys. Rev., B48 (1993) 6436-6450.
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CHAPTER 8
Publication in Journal and Proceedings, andContribution to Scientific Meetings

8.1

Accelerator Operation and Development

8.2

Nuclear Structure

8.3

Nuclear Reaction

8.4

Nuclear Chemistry

8.5

Nuclear Theory

8.6

Atomic Physics and Solid State Physics

8.7

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8. 1

Accelerator Operation and Development

Journal / Proceedings
M. Matsuda, M. Sataka, S. Takeuchi, Y. Tsukihashi, S. Hanashima, S. Abe, A. Osa, N. Ishizaki, H. Tayama,
T. Nakanoya, H. Kabumoto, M. Nakamura, K. Kutsukake, Y. Otokawa, and I. Ohuchi
Present Status of JAEA-Tokai Tandem Accelerator
JAEA-Conf 2008-005 (2008) 42-45.
M. Matsuda, T. Nakanoya, K. Kutsukake, and S. Takeuchi
Development of the heavy ion injector in the high voltage terminal
Proc. of the 4th Annual Meeting of Particle Accelerator Society of Japan and the 32nd Linear Accelerator
Meeting in Japan, Wako, Japan (Aug. 1-3, 2007) 736-738.
H. Kabumoto, S. Takeuchi, N. Ishizaki, and Y. Otokawa
Performance test of low beta superconducting twin quarter wave resonator
Proc. of the 4th Annual Meeting of Particle Accelerator Society of Japan and the 32nd Linear Accelerator
Meeting in Japan, Wako, Japan (Aug. 1-3, 2007) 469-471.
H. Kabumoto, S. Takeuchi, N. Ishizaki, and Y. Otokawa
Development of low beta superconducting twin quarter wave resonator
JAEA-Conf 2008-005 (2008) 137-140.
A. OsaStatus of JAEA-KEK radioactive ion beam facility, TRIAC
Nucl. Instrum. Methods Phys. Res., B261 (2007) 1048.

Meetings
M. Matsuda, M. Sataka, S. Takeuchi, Y. Tsukihashi, S. Hanashima, S. Abe, A. Osa, N. Ishizaki, H. Tayama,
T. Nakanoya, H. Kabumoto, M. Nakamura, K. Kutsukake, Y. Otokawa, and I. Ohuchi
Present Status of JAEA-Tokai Tandem Accelerator
The 20th Meeting for Tandem Accelerators and their Associated Technologies, Tokai, Japan (Jul. 12, 2007).
M. Matsuda, T. Nakanoya, K. Kutsukake, and S. Takeuchi
Development of the heavy ion injector in the high voltage terminal
The 4th Annual Meeting of Particle Accelerator Society of Japan and the 32nd Linear Accelerator Meetingin Japan, Wako, Japan (Aug. 3, 2007).
H. Kabumoto, S. Takeuchi, N. Ishizaki, and Y. Otokawa－ 113 －

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Performance test of low beta superconducting twin quarter wave resonator
The 4th Annual Meeting of Particle Accelerator Society of Japan and the 32nd Linear Accelerator Meetingin Japan, Wako, Japan (Aug. 2, 2007).
H. Kabumoto, S. Takeuchi, N. Ishizaki, and Y. Otokawa
Development of low beta superconducting twin quarter wave resonator
The 20th Meeting for Tandem Accelerators and their Associated Technologies, Tokai, Japan (Jul. 12, 2007).
A. Osa, S. Ichikawa, M. Matsuda, T.K. Sato, and S.C. Jeong
Ion source development for the on-line isotope separator at JAEA
15th International Conference on Electromagnetic Isotope Separators and Techniques Related to their
Applications (EMIS2007), Deauville, France (Jun. 26, 2007).
A. Osa, M. Matsuda, T.K. Sato, and S. Ichikawa
Release and efficiencies of radioactive ion beams from the JAEA-ISOL target/ion source systems
15th International Conference on Electromagnetic Isotope Separators and Techniques Related to their
Applications (EMIS2007), Deauville, France (Jun. 25, 2007).

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8. 2 Nuclear Structure
Journal / Proceedings
Y.H. Zhang, S. Guo, X. H. Zhou, L. Ma. W. T. Guo, M. Oshima, Y. Toh, M. Koizumi, A. Osa, A. Kimura, Y.
Hatsukawa, M. Sugawara, and H. Kusakari
Identification of a new band and its signature inversion in 174Re
Chin. Phys. Lett., 24 (2007) 1203-1206.
T. Shizuma, T. Ishii, H. Makii, T. Hayakawa, S. Shigematsu, M. Matsuda, E. Ideguchi, Y. Zheng, M. Liu,and T. Morikawa
Evidence for a Kπ=1/2+ isomer in neutron-rich 185Ta
Eur. Phys. J., A34 (2007) 1-4.
T. Shizuma, T. Ishii, H. Makii, T. Hayakawa, S. Shigematsu, M. Matsuda, E. Ideguchi, Y. Zheng, M. Liu, T.
Morikawa, and M. Oi
One-quasiparticle bands in neutron-rich 187W
Phys. Rev., C77 (2007) 047303 (1-4).
Y. Liu, X.H. Zhou, Y.H. Zhang, M.L. Liu, Y.X. Guo, M. Oshima, Y. Toh, M. Koizumi, A. Osa, Y.
Hatsukawa, and Y. Sun
Prolate and oblate shape coexistence in 188Pt
Chin. Phys. Lett., 25 (2008) 1633-1635.
H. Makii, T. Ishii, M. Asai, K. Tsukada, A. Toyoshima, M. Matsuda, A. Makishima, J. Kaneko, H. Toume,
S. Ichikawa, S. Shigematsu, T. Kohno, and M. Ogawa
Z dependence of the N = 152 deformed shell gap: In-beam γ-ray spectroscopy of neutron-rich 245, 246Pu
Phys. Rev. C 76 (2007) 061301(R) (1-5).
T. Ishii, H. Makii, M. Asai, H. Koura, S. Shigematsu, K. Tsukada, A. Toyoshima, M. Matsuda, A.
Makishima, J. Kaneko, H. Toume, I. Hossain, T. Shizuma, S. Ichikawa, T. Kohno, and M. Ogawa
Ground-state bands of neutron-rich 236Th and 242U nuclei and implication of spherical shell closure at
N=164
Phys. Rev., C76 (2007) 011303(R) (1-5).
H. Iimura, T. Horiguchi, Y. Ishida, M. Ito, M. Koizumi, M. Miyabe, and M. Oba
Production of 186mRe from proton bombardment of enriched 186W
J. Phys. Soc. Jpn., 77 (2008) 025004 (1-2).

H. Iimura and F. Buchinger
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JAEA-Review 2008-054

Phys. Rev., C76 (2007) 057302 (1-4).
H. Hayashi, Y. Akita, O. Suematsu, M. Shibata, M. Asai, T. K. Sato, S. Ichikawa, I. Nishinaka, Y. Nagame,
A. Osa, K. Tsukada, T. Ishii, Y. Kojima, and A. Taniguchi
Qβ measurements of 158,159Pm, 159,161Sm, 160-165Eu, 163Gd and 166Tb using a total absorption BGO
detector
Eur. Phys. J., A34 (2008) 363-370.

Meetings
E. Ideguchi, M. Liu, T. Morikawa, Y. Toh, M. Koizumi, M. Oshima, A. Kimura, K. Furutaka, Y. Hatsukawa,
B. Cederwall, Y. Zheng, H. Kusakari, M. Sugawara, and S. Mitarai
Study of high-spin states in A～30 region via 18O+24Mg reaction
2007 Fall Meeting of the Physical Society of Japan, Sapporo, Japan (Sep. 24, 2007).
T. Morikawa, E. Ideguchi, M. Liu, Y. Zheng, M. Oshima, M. Koizumi, Y. Toh, A. Kimura, A. Osa, H.
Harada, K. Furutaka, S. Nakamura, F. Kitatani, Y. Hatsukawa, M. Sugawara, H. Kusakari, and S. Mitarai
High-spin spectroscopy of neutron-rich 38Cl nucleus
2007 Fall Meeting of the Physical Society of Japan, Sapporo, Japan (Sep. 24, 2007).
T. Morikawa, M. Nakamura, T. Sugimitsu, H. Kusakari, S. Mitarai, M. Oshima, Y. Toh, Y. Hatsukawa, J.
Katakura, M. Koizumi, A. Osa, A. Kimura, J. Goto, E. Ideguchi, M. Liu, Y. Zheng, and M. Sugawara
Spectroscopy of 33P and high-spin study of neutron-rich nuclei via fusion evaporation reactions
International Nuclear Physics Conference 2007 (INPC2007), Tokyo, Japan (Jun. 6, 2007).
T. Shizuma, T. Ishii, H. Makii, T. Hayakawa, S. Shigematsu, M. Matsuda, E. Ideguchi, Y. Zheng, M. Liu, T.
Morikawa, P.M. Walker, and M. Oi
Spectroscopy of neutron-rich 187,188W produced in neutron transfer reactions
International Nuclear Physics Conference 2007 (INPC2007), Tokyo, Japan (Jun. 4, 2007).
H. Makii, T. Ishii, M. Asai, K. Tsukada, A. Toyoshima, M. Matsuda, A. Makishima, J. Kaneko, H. Toume,
S. Ichikawa, S. Shigematsu, T. Kohno, and M. Ogawa
In-beam γ-ray spectroscopy of neutron-rich 245, 246Pu and properties of N = 152 deformed shell closure
Nuclear Structure: New Pictures in the Extended Isospin Space, Kyoto, Japan (Jun. 14, 2007).
T. Ishii, H. Makii, M. Asai, H. Koura, S. Shigematsu, K. Tsukada, A. Toyoshima, M. Matsuda, A.
Makishima, T. Shizuma, J. Kaneko, H. Toume, I. Hossain, S. Ichikawa, T. Kohno, and M. Ogawa
In-beam γ-ray spectroscopy of neutron-rich nuclei in the uranium region through the heavy-ion transfer
reactionInternational Nuclear Physics Conference 2007 (INPC2007), Tokyo, Japan (Jun. 4, 2007).
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T. Ishii, H. Makii, M. Asai, K. Tsukada, A. Toyoshima, M. Matsuda, T. Shizuma, A. Makishima, H. Toume,
S. Shigematsu, T. Kohno , Ogawa, and I. Hossain
High-j quasi-particle states in 249Cm
2008 Spring Meeting of the Physical Society of Japan, Osaka, Japan (Mar. 23, 2008).
T. Ishii
In-beam γ-ray spectroscopy of neutron-rich nuclei in the uranium region
4th Meeting on Nuclear Physics of Slow and Stop Radio Isotope (SSRI4), Sendai, Japan (Dec. 21, 2007).
M. Asai
Gamma-ray spectroscopy of the heaviest nuclei
International Workshop on Nuclear Structure: New Pictures in the Extended Isospin Space (NS07), Kyoto,
Japan (Jun. 13, 2007).
M. Asai, K. Tsukada, M. Sakama, Y. Ishii, A. Toyoshima, T. Ishii, I. Nishinaka, Y. Nagame, Y. Kasamatsu,
H. Haba, Y. Kojima, M. Shibata, H. Hayashi, and K. Sueki
Alpha-gamma spectroscopy N = 155 and 157 nuclei using a gas-jet transport technique
The 3rd International Conference on the Chemistry and Physics of the Transactinide Elements (TAN07),
Davos, Switzerland (Sep. 27, 2007).
M. Asai, K. Tsukada, Y. Ishii, A. Toyoshima, T. Ishii, I. Nishinaka, and Y. Nagame
Alpha fine structure spectroscopy for heavy- and transactinide nuclei
The 3rd International Conference on the Chemistry and Physics of the Transactinide Elements (TAN07),
Davos, Switzerland (Sep. 25, 2007).
H. Schuessler, F. Buchinger, T. Cocolios, J.E. Crawford, S. Gulick, H. Iimura, J.K.P. Lee, C.D.P. Levy, M.
Pearson, V. Lioubimov, F. Zhu, J. Rikovska, S.D. Rosner, R. Thompson, and R. Wyss
Nuclear moments of the radioactive isotope 131La determined by collinear fast-beam laser spectroscopy
International Nuclear Physics Conference 2007 (INPC2007), Tokyo, Japan (Jun. 4, 2007).
H. Iimura and F. Buchinger
Nuclear charge radii calculated with mass models taking axially asymmetric deformation into
consideration
63rd Annual Meeting of the Physical Society of Japan, Higashiosaka, Japan (Mar. 24, 2008).
Y. Hirayama
Nuclear Spectroscopy with polarized radioactive beam by tilted foil technique
4th Meeting on Nuclear Physics of Slow and Stop Radio Isotope (SSRI4), Sendai, Japan (Dec. 20, 2007).
M. Asai－ 117 －

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Alpha fine structure spectroscopy for the heaviest nuclei
4th Meeting on Nuclear Physics of Slow and Stop Radio Isotope (SSRI4), Sendai, Japan (Dec. 21, 2007).

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8. 3 Nuclear Reaction
Journal / Proceedings
S. Mitsuoka, H. Ikezoe, K. Nishio, K. Tsuruta, S.C. Jeong, and Y. Watanabe
Barrier distributions derived from quasielastic backscattering of 48Ti, 54Cr, 56Fe, 64Ni and 70Zn projectiles
on a 208Pb target
Phys. Rev. Lett. 99, 182701 (2007).
Z. Muhammad, K. Hagino, S. Mitsuoka, and H. Ikezoe
Coupled-channels analyses for large-angle quasi-elastic scattering in massive systems
Phys. Rev. C77, 034604 (2008).
K. Nishio, S. Hofmann, H. Ikezoe, F.P. Hessberger, D. Ackermann, S. Antalic, V.F. Comas, Z. Gan, S.
Heinz, J.A. Heredia, J. Khuyagbaatar, B. Kindler, I. Kojouharov, P. Kuusiniemi, B. Lommel, R. Mann, M.
Mazzocco, S. Mitsuoka, Y. Nagame, T. Ohtsuki, A.G. Popeko, S. Saro, H.J. Schött, B. Sulignano, A.
Svirikhin, K. Tsukada, K. Tsuruta, and A.V. Yeremin
Measurement of evaporation residue and fission cross-sections of the reaction 30Si + 238U at subbarrierenergies
J. Nucl. and Rad. Sci., 8 (2007) 73-78.
J. Murata, K. Asahi, D. Kameda, H. Kawamura, D. Nagae, K. Narita, K. Shimada, T. Shimoyama, T.
Suehiro, T. Toyoda, M .Uchida, H. Ueno, and A. Yoshimi
Beta neutrino correlation and T-violation experiment in nuclear beta decay
AIP Conference Proceedings, 915 (2007) 218.

Meetings
Y. Watanabe, S. Mitsuoka, K. Nishio, S.C. Jeong, T. Hashimoto, Y. Hirayama, N. Imai, H. Ishiyama, H.
Miyatake, and H. Ikezoe
Measurement of quasi-elastic back-scattering of 64Ni+118Sn and 58Ni+124Sn
63rd Annual Meeting of the Physical Society of Japan, Osaka, Japan (Mar. 23, 2008).
Y. Watanabe
Experiments for possible effect of neutron transfer on fusion process
4th Meeting on Nuclear Physics of Slow and Stop Radio Isotope (SSRI4), Sendai, Japan (Dec. 21, 2007).

S. Mitsuoka, H. Ikezoe, K. Nishio, K. Tsuruta, S.C. Jeong, and Y. Watanabe
Barrier distributions for quasi-elastic back-scattering of 48Ti, 54Cr, 56Fe, 64Ni and 70Zn projectiles on
208

Pb target－ 119 －

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International Workshop on Nuclear Structure, Kyoto, Japan (Jun.13, 2007).
S.Mitsuoka, H.Ikezoe, K.Nishio, T. Hashimoto, S.C. Jeong, Y. Watanabe, H. Miyatake, H. Ishiyama,
N. Imai, and Y. Hirayama
Barrier distribution for sub-barrier fusion of deformed nuclei
Annual Meeting of the Physical Society of Japan, Sapporo, Japan (Sep. 24, 2007).
K. Nishio, H. Ikezoe, S. Mitsuoka, I. Nishinaka, Y. Watanabe, Y. Nagame, T. Ohtsuki, and K. Hirose
Effects of nuclear deformation of 238U on the fission fragment mass distribution in the reaction of 36S + 238U
2008 Spring Meeting of the Physical Society of Japan, Osaka, Japan (Mar. 23, 2008).
K. Nishio, H. Ikezoe, S. Mitsuoka, I. Nishinaka, Y. Watanabe, Y. Nagame, T. Ohtsuki, and K. Hirose
Measurement of fission fragment mass distributions in the sub-barrier reaction of 36S + 238U
2008 Spring Meeting of the Atomic Energy Society of Japan, Osaka, Japan (Mar. 26., 2008).
K. Nishio, H. Ikezoe, S. Hofmann, F.P. Hessberger, D. Ackermann, S. Antalic, V.F. Comas, Z. Gan, S.
Heinz, J.A. Heredia, J. Khuyagbaatar, B. Kindler, I. Kojouharov, P. Kuusiniemi, B. Lommel, R. Mann, M.
Mazzocco, S. Mitsuoka, Y. Nagame, T. Ohtsuki, A.G. Popeko, S. Saro, H.J. Schött, B. Sulignano, A.
Svirikhin, K. Tsukada, K. Tsuruta, and A.V. Yeremin
Orientation effects of deformed 238U target nuclei on the fusion probability for the heavy element synthesis
International Nuclear Physics Conference 2007 (INPC2007), Tokyo, Japan (Jun. 6, 2007).
K. Nishio, H. Ikezoe, S. Hofmann, F.P. Hessberger, D. Ackermann, S. Antalic, V.F. Comas, Z. Gan, S.
Heinz, J.A. Heredia, J. Khuyagbaatar, B. Kindler, I. Kojouharov, P. Kuusiniemi, B. Lommel, R. Mann, M.
Mazzocco, S. Mitsuoka, Y. Nagame, T. Ohtsuki, A.G. Popeko, S. Saro, H.J. Schött, B. Sulignano, A.
Svirikhin, K. Tsukada, K. Tsuruta, and A.V. Yeremin
Orientation effects of deformed 238U target nuclei on the fusion probability for heavy eleemt synthesis
International Workshop on Nuclear Structure (NS07), Kyoto, Japan (Jun. 14, 2007).
K. Nishio, H. Ikezoe, S. Hofmann, F.P. Hessberger, D. Ackermann, S. Antalic, V.F. Comas, Z. Gan, S.
Heinz, J.A. Heredia, J. Khuyagbaatar, B. Kindler, I. Kojouharov, P. Kuusiniemi, B. Lommel, R. Mann, M.
Mazzocco, S. Mitsuoka, Y. Nagame, T. Ohtsuki, A.G. Popeko, S. Saro, H.J. Schött, B. Sulignano, A.
Svirikhin, K. Tsukada, K. Tsuruta, and A.V. Yeremin
Orientation effects of deformed target nuclei on the fusion probability for heavy element synthesis
3rd. International Conf. on the Chemistry and Physics of the Transactindie Elements (TAN07), Davos,
Switzerland, Davos (Sep. 24, 2007).
J. Murata
T-violating transverse electron polarization in polarized nuclear beta decayInternational Nuclear Physics Conference (INPC 2007), Tokyo, Japan (Jun. 6, 2007).

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T. Hashimoto, S. Mitsuoka, K. Nishio, T.K. Sato, A. Osa, S. Ichikawa, M. Matsuda, H. Ikezoe, H. Ishiyama,
Y.X. Watanabe, Y. Hirayama, N. Imai, H. Miyatake, S.C. Jeong, M.H. Tanaka, N. Yoshikawa, T. Nomura,
S.K. Das, Y. Mizoi, T. Fukuda, S. Bishop, A. Sato, and T. Shimoda
Direct measurement of the astrophysical 8Li(d, t)7Li reaction
Direct Reaction with Exotic Beams 2007, Wako, Japan (May. 30, 2007).
H. Ishiyama, Y.X. Watanabe, Y. Hirayama, N. Imai, H. Miyatake, M.H. Tanaka, N. Yoshikawa, S.C. Jeong,
Y. Fuchi, T. Nomura, I. Katayama, H. Kawakami, T. Hashimoto, K. Nishio, S. Mitsuoka, H. Ikezoe, M.
Matsuda, S. Ichikawa, T.K. Sato, A. Osa, S.K. Das, Y. Mizoi, T. Fukuda, T. Shimoda K. Otsuki, and T.
KajinoA systematic study of astrophysical nuclear reaction rates via 8Li
International Nuclear Physics Conference 2007 (INPC2007), Tokyo, Japan (Jun. 5, 2007).
T. Hashimoto, H. Ishiyama, Y.X. Watanabe, Y. Hirayama, N. Imai, H. Miyatake, S.C. Jeong, M.H. Tanaka,
N. Yoshikawa, T. Nomura, S. Mitsuoka, K. Nishio, T.K. Sato, S. Ichikawa, H. Ikezoe, A. Osa, M. Matsuda,
S.K. Das, Y. Mizoi, T. Fukuda, A. Sato, and T. Shimoda
Direct measurement of 8Li + d reactions of astrophysical interest
10th International Symposium on Origin of Matter and Evolution of Galazies, Hokkaido, Japan (Dec. 6,2007).
H. Ishiyama, Y.X. Watanabe, Y. Hirayama, N. Imai, H. Miyatake, M.H. Tanaka, N. Yoshikawa, S.C. Jeong,
Y. Fuchi, T. Nomura, I. Katayama, H. Kawakami, T. Hashimoto, K. Nishio, S. Mitsuoka, H. Ikezoe, M.
Matsuda, S. Ichikawa, T.K. Sato, A. Osa, S.K. Das, Y. Mizoi, T. Fukuda, T. Shimoda K. Otsuki, and T.
KajinoDetermination of astrophysical nuclear reaction rates on neutron-rich nuclei
3rd Japanese-German EFES(JSPS)-DEG/GSI workshop on Nuclear Structure and Astrophysics, Frauenw
im Chiemsee, German (Sep. 30, 2007).
H. Ishiyama, Y.X. Watanabe, H. Miyatake, M.H. Tanaka,Y. Fuchi, Y. Hirayama, N. Imai, S.C. Jeong, I.
Katayama, T. Nomura, T. Hashimoto, S. Mitsuoka, K. Nishio, M. Matsuda, A. Osa, T.K. Sato, S. Ichikawa,
H. Ikezoe, Y. Mizoi, S.K. Das, T. Fukuda, Y. Yamaguchi, T. Shimoda, K. Otsuki, and T. Kajino
Development of the GEM-MSTPC for cross section measurements with low-energy RNBs
Japanese-French workshop on Next generation of detectors with RI beams, Ganil, France (Feb. 14, 2007).
H. Ishiyama
Determination of astrophysical nuclear reaction rates with radioactive nuclear beams at TRIAC
Year meeting of the Physical Society of Japan, Sapporo, Japan (Sep. 21, 2007).
T. Hashimoto, H. Ishiyama, Y.X. Watanabe, Y. Hirayama, N. Imai, H. Miyatake, S.C. Jeong, M.H. Tanaka,
N. Yoshikawa, T. Nomura, S. Mitsuoka, K. Nishio, T.K. Sato, S. Ichikawa, H. Ikezoe, A. Osa, M. Matsuda,－ 121 －

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S.K. Das, Y. Mizoi, T. Fukuda, A. Sato, and T. Shimoda
Direct measurements of the 8Li(d, p), (d, t) and (d, α) reactions
Year meeting of the Physical Society of Japan, Sapporo, Japan (Sep. 21, 2007).
Y. Mizoi, T. Fukuda, S.K. Das, H. Ishiyama, Y.X. Watanabe, M-H. Tanaka, H. Miyatake, and T. Hashimoto
Development of the GEM-MSTPC for low-energy nuclear reactions
Year meeting of the Physical Society of Japan, Sapporo, Japan (Sep. 22, 2007).
K. Yamaguchi, H. Ishiyama, M-H. Tanaka, Y.X. Watanabe, H. Miyatake, Y. Hirayama, N. Imai, Y, Fuchi,
S.C. Jeong, T. Nomura, Y. Mizoi, T. Fukuda, S.K. Das, and T. Hashimoto
Development of the GEM-MSTPC for low-energy nuclear reactions II
Year meeting of the Physical Society of Japan, Osaka Japan (Mar. 24, 2008).

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8. 4 Nuclear Chemistry
Journal / Proceedings
Y. Nagame, I. Nishinaka, Y.L. Zhao, and H. Nakahara
Symmetric and asymmetric scission properties in the fission of pre-actinides through heavy actinides
Rum. Rep. Phys., 59 (2007) 362-376.
Y. Kasamatsu, A. Toyoshima, H. Toume, K. Tsukada, H. Haba, and Y. Nagame
Anion-exchange behavior of Nb, Ta, and Pa as homologues of Db in HF/HNO3 solutions
J. Nucl. Radiochem. Sci., 8 (2007) 69-72.
H. Haba, T. Akiyama, D. Kaji, H. Kikunaga, T. Kuribayashi, K. Morimoto, K. Morita, K. Ooe, N. Sato, A.
Shinohara, T. Takabe, Y. Tashiro, A. Toyoshima, A. Yoneda, and T. YoshimuraStartup of superheavy element chemistry at RIKEN
Eur. Phys. J., D45 (2007) 81-86.
Y. Ishii, A. Toyoshima, K. Tsukada, M. Asai, H. Toume, I. Nishinaka, Y. Nagame, S. Miyashita, T. Mori, H.
Suganuma, H. Haba, M. Sakamaki, S. Goto, H. Kudo, K. Akiyama, Y. Oura, H. Nakahara, Y. Tashiro, A.
Shinohara, M. Schädel, W. Brüchle, V. Pershina, and J.V. Kratz
Fluoride complexation of element 104, rutherfordium (Rf), investigated by cation-exchange
chromatography
Chem. Lett., 37 (2008) 288-289.
A. Toyoshima, H. Haba, K. Tsukada, M. Asai, K. Akiyama, S. Goto, W. Sato, Y. Ishii, I. Nishinaka, T. K.
Sato, Y. Nagame, Y. Tani, H. Hasegawa, K. Matsuo, D. Saika, Y. Kitamoto, A. Shinohara, M. Ito, J. Saito,
H. Kudo, A. Yokoyama, M. Sakama, K. Sueki, Y. Oura, H. Nakahara, M. Schädel, W. Brüchle, and J. V.
Kratz
Hexafluoro complex of rutherfordium in mixed HF/HNO3 solutions
Radiochim. Acta 96 (2008) 125-134.
Y. Nagame and H. Haba
Production and chemistry of transactinide elements
in Radiochemistry and Nuclear Chemistry, Ed. Sandor Nagy, in Encyclopedia of Life Support Systems(EOLSS), Developed under the Auspices of the UNESCO, Eolss Publishers, Oxford, UK, 2007[http://www.eolss.net].

Meetings
Y. Nagame
Aqueous chemistry of the transactinide element, rutherfordium (Rf)
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234th American Chemical Society (ACS) National Meeting, Boston, USA (Aug. 21, 2007).
Y. Nagame
Status of superheavy element chemistry
The RIKEN workshop on superheavy elements, Wako, Japan (Aug. 27, 2007).
Y. Kasamatsu
Development of a rapid ion-exchange separation apparatus AIDA-II
The RIKEN workshop on superheavy elements, Wako, Japan (Aug. 27, 2007).
A. Toyoshima
Electrochemistry of superheavy elements
The RIKEN workshop on superheavy elements, Wako, Japan (Aug. 27, 2007).
Y. Nagame
Automated rapid radiochemical separations of the heaviest elements
The 12th International Conference on Modern Trends in Activation Analysis (MTAA12), Tokyo, Japan(Sept. 18, 2007).
Y. Ishii, S. Miyashita, T. Mori, H. Suganuma, H. Toume, Y. Kasamatsu, A. Toyoshima, M. Asai, I.
Nishinaka, K. Tsukada, and Y. Nagame
Adsorption behavior of element 104 rutherfordium on cation-exchange resin in HF/HNO3 solution
The 51st Symposium on Radiochemistry, Shizuoka, Japan (Sept. 24, 2007).
Y. Kasamatsu, H. Toume, A. Toyoshima, K. Tsukada, M. Asai, Y. Ishii, I. Nishinaka, T.K. Sato, N.
Shinohara, Y. Nagame, H. Haba, H. Kikunaga, K. Akiyama, S. Goto, T. Ishikawa, H. Kudo, W. Sato, K.
Ooe, T. Kuribayashi, A. Shinohara, N. Kinoshita, M. Arai, A. Yokoyama, M. Sakama, Z. Qin, and Ch.E.
Düllmann
Chemical behavior of element-105, Db, in mixed HF/HNO3 solutions
The 51st Symposium on Radiochemistry, Shizuoka (Sept. 24, 2007).
Y. Nagame, A. Toyoshima, Y. Ishii, K. Tsukada, M. Asai, H. Toume, Y. Kasamatsu, I. Nishinaka, T. K. Sato,
H. Haba, H. Kikunaga, K. Akiyama, Y. Oura, H. Nakahara, W. Sato, A. Shinohara, S. Goto, H. Kudo, A.
Yokoyama, M. Sakama, K. Sueki, M. Schädel, W. Brüchle, and J.V. Kratz
Fluoride complex formation of element 104, rutherfordium
3rd International Conference on the Chemistry and Physics of the Transactinide Elements, Davos,
Switzerland (Sept. 26, 2007).
Y. Kasamatsu, A. Toyoshima, M. Asai, K. Tsukada, H. Haba, Y. Ishii, H. Toume, I. Nishinaka, K. Akiyama,
H. Kikunaga, S. Goto, T. Ishikawa, H. Kudo, W. Sato, K. Ooe, T. Kuribayashi, A. Shinohara, N. Kinoshita,
M. Arai, A. Yokoyama, M. Sakama, T.K. Sato, Z. Qin, Ch.E. Düllmann, and Y. Nagame－ 124 －

JAEA-Review 2008-054

Anion-exchange behavior of element 105, Db, in HF/HNO3 media
3rd International Conference on the Chemistry and Physics of the Transactinide Elements, Davos,
Switzerland (Sept. 26, 2007).
A. Toyoshima, Y. Kasamatsu, K. Tsukada, A. Kitatsuji, H. Haba, Y. Ishii, H. Toume, M. Asai, K. Akiyama,
K. Ooe, W. Sato, A. Shinohara, and Y. Nagame
Electrochemical oxidation of nobelium
3rd International Conference on the Chemistry and Physics of the Transactinide Elements, Davos,
Switzerland (Sept. 26, 2007).
K.Tsukada, Y. Kasamatsu, M. Asai, A. Toyoshima, Y. Ishii, H. Toume, and Y. Nagame
New apparatus AIDA-II for aqueous chemistry of the heaviest elements
3rd International Conference on the Chemistry and Physics of the Transactinide Elements, Davos,
Switzerland (Sept. 27, 2007).
A. Toyoshima
Chemical properties of Rf
The Specialist’s Meeting on the Nuclear Science of Heavy Elements, KURRI, Kumatori, Japan (Dec. 11,
2007).
A. Toyoshima
Electrochemistry of superheavy elements
The Specialist’s Meeting on the Nuclear Science of Heavy Elements, KURRI, Kumatori, Japan (Dec. 11,
2007).
M. AsaiSingle atom chemistry
The Specialists’ Meeting on the Nuclear Science of Heavy Elements, KURRI, Kumatori, Japan (Dec. 11,
2007).
Y. Kasamatsu, A. Toyoshima, M. Asai, K. Tsukada, H. Haba, Y. Ishii, H. Toume, I. Nishinaka, K. Akiyama,
H. Kikunaga, S. Goto, T. Ishikawa, H. Kudo, W. Sato, K. Ooe, T. Kuribayashi, A. Shinohara, N. Kinoshita,
M. Arai, A. Yokoyama, M. Sakama, T.K. Sato, and Y. Nagame
Adsorption of element-105 (Db) on anion-exchange resin in HF/HNO3 solutions
The 88th Spring Meeting of the Chemical Society of Japan, Tokyo, Japan (Mar. 28, 2007).

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8. 5 Nuclear Theory
Journal / Proceedings
T. Maruyama, S. Chiba, H.-J. Schulze, and T. Tatsumi
Hadron-quark mixed phase in hyperon stars
Phys. Rev., D76 (2007) 123015-1-12.
T. Maruyama, S. Chiba, H.-J. Schulze, and T. Tatsumi
Quark deconfinement transition in hyperonic matter
Phys. Lett., B659 (2008) 192-196.
T. Maruyama, S. Chiba, H.-J. Schulze, and T. Tatsumi
Hyperon-quark mixed phase in dense matter
Proceedings of Int. Symp. Exotic States of Nuclear Matter, Catania, Italy (Jun. 11-15, 2007),
World Scientific (2008) 290-297.
Y. Utsuno, T. Otsuka, T. Mizusaki, and M. Honma
Structure of unstable nuclei in the sd-pf shell region by shell model with proper tensor force
Eur. Phys. J. Special Topics, 150 (2007) 187-188.
S. Chiba, H. Koura, T. Hayakawa, T. Maruyama, T. Kawano, and T. Kajino
Direct and semi-direct capture in low-energy (n,γ) reactions of neutron-rich tin isotopes and its
implications for r-process nucleosynthesis
Phys. Rev., C77 (2008) 015809-1-7.
S. Oryu, S. Nishinonara, and S. Chiba
The rigorous few-body Coulomb treatments and its application to the proton-proton phase-shift calcualtion
Quantum Probability and White Noise Analysis Volume XXI, Quantum Bio-Informatics, From Quantum
Information to Bio-Informatics, Eds. L. Accardi, W. Freudenberg, and M. Ohya, World Scientific (2008)229-246.
S. Nishinohara, S. Chiba, and S. Oryu
The Coulomb scattering in momentum space for few-body systems
Nucl. Phys., A790 (2007) 277-281.
L. Bonneau, T. Kawano, T. Watanabe, and S. Chiba,
Nucleon direct-semidirect radiative capture with Skyrme-Hartree-Fock-BCS bound statePhys. Rev., C75 (2007) 054618-1-10.
S. Kunieda, S. Chiba, K. Shibata, A. Ichihara, and E.Sh. Sukhovitskii－ 126 －

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Coupled-channels optical model analyses of nucleon-induced reactions for medium and heavy nuclei in theenergy region from 1 keV to 200 MeV
J. Nucl. Sci. Technol., 44 (2007) 838-852.
K. Morita, K. Morimoto, D. Kaji, T. Akiyama, S. Goto, H. Haba, E. Ideguchi, K. Katori, H. Koura, H.
Kudo, T. Ohnishi, A. Ozawa, T. Suda, K. Sueki, F. Tokanai, T. Yamaguchi, A. Yoneda, and A. Yoshida
Experiment on synthesis of an isotope 277112 by 208Pb+70Zn reaction
Journal of the Physical Society of Japan, 76 (2007) 043201.
K. Morita, K. Morimoto, D. Kaji, T. Akiyama, S. Goto, H. Haba, E. Ideguchi, K. Katori, H. Koura, H.
Kikunaga, H. Kudo, T. Ohnishi, A. Ozawa, N. Sato, T. Suda, K. Sueki, F. Tokanai, T. Yamaguchi, A.
Yoneda, and A. Yoshida
Observation of second decay chain from 278113
Journal of the Physical Society of Japan, 76 (2007) 045001.
A. Gade, P. Adrich, D. Bazin, M.D. Bowen, B.A. Brown, C.M. Campbell, J.M. Cook, S. Ettenauer, T.
Glasmacher, K.W. Kemper, S. McDaniel, A. Obertelli, T. Otsuka, A. Ratkiewicz, K. Siwek, J.R. Terry, J.A.
Tostevin, Y. Utsuno, and D. Weisshaar
Spectroscopy of 36Mg : Interplay of normal and intruder configurations at the neutron-rich boundary of the"island of inversion"
Phys. Rev. Lett., 99 (2007) 072502-1-4.
P. Doornenbal, P. Reiter, H. Grawe, T. Otsuka, A. Al-Khatib, A. Banu, T. Beck, F. Becker, P. Bednarczyk, G.
Benzoni, A. Bracco, A. Burger, L. Caceres, F. Camera, S. Chmel, F.C.L. Crespi, H. Geissel, J. Gerl, M.
Gorska, J. Grebosz, H. Hubel, M. Kavatsyuk, O. Kavatsyuk, M. Kmiecik, I. Kojouharov, N. Kurz, R.
Lozeva, A. Maj, S. Mandal, W. Meczynski, B. Million, Zs. Podolyak, A. Richard, N. Saito, T. Saito, H.
Schaffner, M. Seidlitz, T. Striepling, Y. Utsuno, J. Walker, N. Warr, H. Weick, O. Wieland, M. Winkler, and
H.J. Wollersheim
The T = 2 mirrors 36Ca and 36S : A test for isospin symmetry of shell gaps at the driplines
Phys. Lett., B647 (2007) 237-242.
V. Tripathi, S.L. Tabor, P.F. Mantica, Y. Utsuno, P. Bender, J. Cook, C.R. Hoffman, S. Lee, T. Otsuka, J.
Pereira, M. Perry, K. Pepper, J.S. Pinter, J. Stoker, A. Volya, and D. Weisshaar
Competition between normal and intruder states inside the "island of inversion"
Phys. Rev., C76 (2007) 021301(R)-1-5.
J.R. Terry, B.A. Brown, C.M. Campbell, J.M. Cook, A.D. Davies, D.-C. Dinca, A. Gade, T. Glasmacher,
P.G. Hansen, B.M. Sherrill, H. Zwahlen, D. Bazin, K. Yoneda, J.A. Tostevin, T. Otsuka, Y. Utsuno, and B.
Pritychenko
Single-neutron knockout from intermediate energy beams of 30 32Mg : Mapping the transition into the"island of inversion"－ 127 －

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Phys. Rev., C77 (2008) 014316-1-12.
P. Himpe, G. Neyens, D.L. Balabanski, G. Belier, J.M. Daugas, F.de Oliveira Santos, M.De Rydt, K.T.
Flanagan, I. Matea, P. Morel, Yu.E. Penionzhkevich, L. Perrot, N.A. Smirnova, C. Stodel, J.C. Thomas, N.
Vermeulen, D.T. Yordanov, Y. Utsuno, and T. Otsuka,
g factor of the exotic N = 21 isotope 34Al : probing the N = 20 and N = 28 shell gaps at the border of the"island of inversion"
Phys. Lett., B658 (2008) 203-208.

Meetings
Y. Utsuno, T. Otsuka, T. Mizusaki, and M. Honma
Shell evolution and exotic structure in the sd-pf shell by the tensor force
ECT Workshop "Advanced Many-Body Methods for Nuclear Physics, Trento, Italy (Jul. 5, 2007).
Y. Utsuno, T. Otsuka, T. Mizusaki, M. Honma, and B.A. Brown,Role of shell evolution in the structure of exotic nuclei in the sd-pf shell
Workshop at the INT Fall-07 Program on Correlations in Nuclei : From Di-nucleons to Clusters, Seattle,
USA (Nov. 26, 2007).
Y. Utsuno, T. Otsuka, M. Honma, T. Mizusaki, N. Shimizu, and B.A. Brown
Large-scale shell model calculation for exotic nuclei—collaboration between Japan and US
The 2nd LACM-EFES-JUSTIPEN Workshop, Oak Ridge, USA (Jan. 23, 2008).
Y. Utsuno, T. Otsuka, M. Honma, T. Mizusaki, and B.A. Brown
Exploring the single-particle structure in the exotic sd-pf shell region with a new effective interaction
Workshop on Future Prospects for Spectroscopy and Direct Reactions 2008, East Lansing, USA (Feb. 27,
2008).
S. Hashimoto, M. Kohno, K. Ogata, and M. Kawai
Analysis of (K-, K+) inclusive spectrum with semiclassical distorted wave model
The International Workshop on Nuclear Physics at J-PARC, Tokai, Japan (Jun. 2, 2007).
S. Hashimoto, M. Kohno, K. Ogata, and M. Kawai
Analysis of (K-, K+) reaction on heavy targets with semiclassical distorted wave model
The 62nd annual meeting of the physical society of Japan, Sapporo, Japan (Sep. 21, 2007)
T. Maruyama, S. Chiba, and T. Tatsumi
Bulk properties of kaonic nuclei in the mean-field calculation
International Nuclear Physics Conference (INPC2007), Tokyo (Jun. 5, 2007).
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T. Maruyama, S. Chiba, H.-J. Schulze, and T. Tatsumi
Hyperon-quark mixed phase in compact stars
International Nuclear Physics Conference (INPC2007), Tokyo (Jun. 6, 2007).
T. Maruyama, S. Chiba, H.-J. Schulze, and T. Tatsumi
Hyperon-quark mixed phase in dense matter
Int. Symp. on Exotic States in Nuclear Matter, Catania, Italy (Jun. 15, 2007).
T. Maruyama, S. Chiba, and T. Tatsumi
Non-uniform structure of matter and equation of state
Nuclear Dynamics in Heavy-ion Reactions and Neutron Stars, Beijinig, China (Jul. 11, 2007).
T. Muto, T. Maruyama, and T. Tatsumi
Structure of multi-antikaonic nuclei in the relativistic mean-field model
Chiral Symmetry in Hadron and Nuclear Physics, Osaka, Japan (Nov. 14, 2007).
T. Maruyama, S. Chiba, H.-J. Schulze, and T. Tatsumi
Hyperon-quark mixed phase in compact stars
Quark Matter 2008, Jaipur, India (Feb. 5, 2008).
M.S. Smith, E.J. Lingerfelt, C.D. Nesaraja, W.R. Hix, L.F. Roberts, H. Koura, G.M. Fuller, and D. Tytler
Nuclear data for astrophysics : Resources, challenges, strategies, and software solutions
The 2007 International Conference on Nuclear Data for Science and Technology (ND2007), Nice, France(Apr. 26, 2007).
H. Koura, T. Tachibana, and S. Chiba
Systematical study of nuclear decay modes and a limit of existence of nuclei
International Nuclear Physics Conference (INPC2007), Tokyo, Japan, (Jun. 6, 2007).
H. Koura
Decay modes of superheavy nuclei - shell structure and border of existence Cosponsored workshop by RIBF mini workshop and Grand-in-Aid “Search for New Element andChemistry of Superheavy Elements” of MEXT of Japan, ”Problem to synthesis for superheavy elements,”
Wako, Japan (Jul. 24, 2007).
K. Oyamatsu, K. Iida, and H. Koura
Masses of unstable nuclei and the equation of state of asymmetric nuclear matter II
The Physical Society of Japan 62nd Annual Meeting, Sapporo, Japan (Sep. 22, 2007).
H. Koura, T. Tachibana, and S. Chiba
Nuclear decay modes of superheavy nuclei and limit of existence of nuclei－ 129 －

JAEA-Review 2008-054

International Conference on the Chemistry and Physics of the Transactinide Elements (TAN07), Davos,
Switzerland (Sep. 24, 2007).
H. Koura
Nuclear mass formula and its applications - Decay modes of superheavy nuclei and limit of existence of
nuclei Crossing Workshop of Nucleus-Hadron Physics, Tsukuba, Japan (Nov. 20, 2007).
H. Koura
Decay modes of superheavy nuclei and region of existence of nuclei
4th Meeting on Nuclear Physics of Slow and Stop Radio Isotope (SSRI4), Sendai, Japan (Dec. 20, 2007).
H. Koura
R-process element abundance considering nuclear fission in the region of superheavy, neutron-rich nuclei
3rd Japanese-German EFES(JSPS)-DFG/GSI workshop on Nuclear Structure and Astrophysics, Chiemsee,
Germany (Sep. 30, 2007).
H. Koura, T. Tachibana, and S. Chiba
Systematical study of nuclear fission in the region of superheavy and neutron-rich nuclei
Fourth International Conf. on Fission and Properties of Neutron-Rich Nuclei, Florida, U.S.A. (Nov. 14,
2007).
S. Tatsuda, T. Asano, K. Yamamoto, M. Ohta, T. Wada, S. Chiba, H. Koura, T. Maruyama, T. Tachibana, T.
Kajino, K. Sumiyoshi, and K. Ohtsuki
Fission modes of neutron-rich nuclei in the r-process nucleosynthesis
The 10th International Symposium on Origin of Matter and Evolution of Galaxies (OMEG07), Sapporo,
Japan (Dec. 4, 2007).
M.S. Smith, F. Kondev, H. Koura, E. Lingerfelt, K. Buckner, and C. Nesaraja
Nuclear masses : theoretical models, experimental evaluations, & web disseminations
The 2nd LACM-EFES-JUSTIPEN Workshop, Oak Ridge, U.S.A. (Jan. 25, 2008).
K. Oyamatsu, K. Iida, and H. Koura
Masses of unstable nuclei and the equation of state of Aaymmetric nuclear matter III
The Physical Society of Japan 63rd Annual Meeting, Higashi-Osaka, Japan (Mar. 24, 2008).
T. Maruyama, T. Maruyama, S. Chiba, and T. Tatsumi
RMF treatment of nuclear matter at finite temperature
The Physical Society of Japan 63rd Annual Meeting, Higashi-Osaka, Japan (Mar. 24, 2008).
T. Muto, T. Maruyama, and T. Tatsumi－ 130 －

JAEA-Review 2008-054

Multi-kaon bound state of nuclei
The Physical Society of Japan 63rd Annual Meeting, Higashi-Osaka, Japan (Mar. 24, 2008).
H. Matsuyama, T. Maruyama, and K. Yabana
Simulation of nuclear collisions by quark molecular dynamics
The Physical Society of Japan 63rd Annual Meeting, Higashi-Osaka, Japan (Mar. 26, 2008).
S. Chiba, S. Tatsuda, T. Wada, K. Sumiyoshi, K. Otsuki, T. Kajino, H. Koura, T. Maruyama, T. Tachibana,and M. Ohta
The r-process element abundance taking account of a realistic fission fragment mass distribution
International Nuclear Physics Conference (INPC2007), Tokyo, Japan (Jun. 5, 2007).
S. Chiba, S. Nishinohara, and S. Oryu
Exact Coulomb treatment for nuclear reactions in momentum space
International Nuclear Physics Conference (INPC2007), Tokyo, Japan (Jun. 6, 2007).
T. Yoshida, T. Suzuki, S. Chiba, T. Kajino, A. Takamura, K. Kimura, H. Yokomakura, D.H. Hartmann, andT. Otsuka
Neutrino favor mixing in supernova nucleosynthesis
International Nuclear Physics Conference (INPC2007), Tokyo, Japan (Jun. 5, 2007).
S. Tatsuda, T. Wada, M. Ohta, K. Sumiyoshi, K. Otsuki, T. Kajino, H. Koura, S. Chiba, and T. Tachibana
Systematic study for the shell effect in the fission fragment mass distribution ruptured form neutron richnucleiInternational Nuclear Physics Conference (INPC2007), Tokyo, Japan (Jun. 5, 2007).
T. Suzuki, S. Chiba, T. Kajino, T. Yoshida, and T. Otsuka
Neutrino-nucleus reactions based on the recent advances in shell-model calculations
International Nuclear Physics Conference (INPC2007), Tokyo, Japan (Jun. 6, 2007).
S. Chiba, H. Koura, T. Maruyama, S. Kunieda, and E. Soukhovitksii
Systematics and uncertainties of Hamiltonian parameters of soft-rotator model for actinides and its
implications for nuclear-data calculations
Int. Conf. on Nuclear Data for Science and Technology (ND2007), Nice, France (Apr. 25, 2007).
M. Ohta, S. Tatsuda, K. Yamamoto, T. Wada, K. Sumiyoshi, K. Otsuki, T. Kajino, H. Koura, and S. Chiba
Systematic study for the mass distribution of fission fragments in the neutron rich region
Int. Conf. on Nuclear Data for Science and Technology (ND2007), Nice, France (Apr. 25, 2007).
S. Kunieda, S. Chiba, K. Shibata, A. Ichihara, and E. Soukhovitsii
Systematical nucleon-induced optical model analysis for medium and heavy nuclei with coupled-channel－ 131 －

JAEA-Review 2008-054

framework
Int. Conf. on Nuclear Data for Science and Technology (ND2007), Nice, France (Apr. 24, 2007).
J.-Y. Lee, I. Hahn, E. Soukhovitskii, and S. Chiba
Analysis of nuclear level structure and nucleon interaction data
Int. Conf. on Nuclear Data for Science and Technology (ND2007), Nice, France (Apr. 24, 2007). .
R. Capote, E. Soukhovitskii, J.M. Quesada, and S. Chiba
Lane consistency of the dispersive coupled channel optical model potential
Int. Conf. on Nuclear Data for Science and Technology (ND2007), Nice, France (Apr. 23, 2007).
S. Chiba, H. Koura, T. Maruyama, M. Ohta, S. Tatsuda, T. Wada, T. Tachibana, T. Kajino, K. Sumiyoshi,
and K. Ohtsuki
Impact of fission fragment mass distribution on the r-process abundance pattern
Annual meeting of Physical Society of Japan, Sapporo, Japan (Sep. 24, 2007).
T. Maruyama, T. Tatsumi, H.-J. Schulze, and S. Chiba,
Hyperon-quark mixed phase in compact stars
Annual meeting of Physical Society of Japan, Sapporo, Japan (Sep. 24, 2007).
T. Muto, T. Maruyama and T. Tatsumi.
Multi-kaon bound state of nuclei
Annual meeting of Physical Society of Japan, Sapporo, Japan (Sep. 21, 2007).
M. Ohta, S. Tatsuda, T. Wada, S. Chiba, H. Koura, T. Maruyama, T. Kajino, and K. Ohtsuki
Systematic calculation of fission fragment mass distribution by a semi-empirical model
Fall meeting of Atomic Energy Society of Japan, Kitakyushu, Japan (Sep. 27-29, 2007).
S. Chiba, H. Koura, T. Maruyama, M. Ohta, S. Tatsuda, T. Wada, T. Tachibana, K. Sumiyoshi, K. Ohtsuki,
and T. Kajino
The r-process element abundance with a realistic fission fragment mass distribution
The 10th Int. Symp. on Origin of Matter and Evolution of Galaxies (OMEG07), Sapporo, Japan(Dec. 5, 2007)－ 132 －

JAEA-Review 2008-054

8. 6

Atomic Physics and Solid State Physics

Meetings
S. Kawatsura, K. Takahiro, M. Sataka, M. Imai, H. Sugai, H. Shibata, and K. Komaki
High Rydberg states produced in high energy collisions of Nq+ (q=1-3) + He
The 25th International Conference on Photonic, Electronic and Atomic Collisions (XXV ICPEAC),
Freiburg, Germany (Jul. 25, 2007).
S. Kawatsura, K. Takahiro, M. Sataka, M. Imai, K. Ozaki, H. Sugai, H. Shibata, and K. Komaki
Ejected electron spectra from high Rydberg states of Neq+ ions passing through C foils
International Symposium on Charged Particle and Photon Interactions with Matter (ASR-2007), Tokai,
Japan (Nov. 7, 2007).

－ 133 －

JAEA-Review 2008-054

8. 7

Radiation Effects in Materials

Journal / Proceedings
T. Sonoda, M. Kinoshita, N. Ishikawa, M. Sataka, Y. Chimi, N. Okubo, and A. Iwase
Clarification of the properties and accumulation effects of ion tracks in CeO2
Nucl. Instrum. Methods Phys. Res., B 266 (2008) 2882-2886.
K. Yasuda, T. Yamamoto, and S. Matsumura
The atomic structure of disordered ion tracks in magnesium aluminate spinel
Journal of Materials 59 (2007) 27-30.
K. Yasuda, T. Yamamoto, S. Seki, K. Shiiyama, and S. Matsumura
Production and stability of radiation-induced defects in MgAl2O4 under electronic excitation
Nucl. Instrum. Methods Phys. Res., B 266 (2008) 2834-2841.
N. Matsunami, M. Sataka, S. Okayasu, and M. Tazawa
Electronic sputtering of nitrides by high-energy ions
Nucl. Instrum. Methods Phys. Res., B256 (2007) 333-336.
F. Hori, M. Fukuzumi, A. Kawasuso, Y. Zushi, Y. Chimi, N. Ishiawa, and A. Iwase
Characterization of swift heavy ion induced defects in FeRh alloy by using positron beam techniquePhys. stat. sol. (c) 4 (2007) 3530-3533.
M. Sasase, K. Shimura, K. Yamaguchi, H. Yamamoto, S. Shamoto, and K. Hojou
Sputter etching effect of the substrate on the microstructure of β-FeSi2 thin film prepared by ion beam
sputter deposition method
Nucl. Instrum. Methods Phys. Res., B257 (2007) 186-189.

Meetings
T. Sonoda, M. Kinoshita, N. Ishikawa, M. Sataka, Y. Chimi, S. Okubo, A. Iwase, and K. Yasunaga
Clarification of the properties and accumulation effects of ion tracks in CeO2
14th International Conference on Radiation Effects in Insulators (REI-2007), Caen, France (Aug. 30,2007).
T. Sonoda, N. Ishikawa, M. Sataka, S. Okubo, K. Yasunaga, K. Yasuda, K. Shiiyama, S. Matsumura, A.
Iwase, and M. Kinoshita,
New cross-over project study (6)High density electronic excitation effects in Xe-ions-implanted fluorite

ceramics as simulations of high burnup nuclear fuels－ 134 －

JAEA-Review 2008-054

2007 Fall Meeting of the Atomic Energy Society of Japan, Kitakyushu, Japan (Sep. 28, 2007).
T. Sonoda, K. Yasunaga, N. Ishikawa, M. Sataka, Y. Chimi, S. Okubo, A. Iwase, and M. Kinoshita,
Clarification of ion tracks in CeO2 under irradiation with high energy ions of typical fission products
NXO International Workshop, Tokyo, Japan (Nov. 14, 2007).
N. Ishikawa, Y. Chimi, O. Michikami, Y. Ohta, K. Ohhara, M. Lang, and R. Neumann
Study of structural change in CeO2 irradiated with high-energy ions by means of X-ray diffraction
measurement
14th International Conference on Radiation Effects in Insulators (REI-2007), Caen, France (Aug. 28,
2007).
N. Ishikawa, K. Ohhara, M. Sataka, S. Sakai, O. Michikami, and Y. Ohta
X-ray and raman studies of CeO2 irradiated with high-energy heavy ionsNXO International Workshop, Tokyo, Japan (Nov.14, 2007).
K. Ohhara, N. Ishikawa, S. Sakai, Y. Matsumoto, O. Michikami, and Y. Ohta
X-ray and raman studies of CeO2 irradiated with 200MeV Au
8th Workshop on Ion-beam Analysis of Surface and Interface, Sendai, Japan (Dec. 7, 2007).
K. Ohhara, N. Ishikawa, S. Sakai, Y. Matsumoto, O. Michikami, and Y. Ohta
Irradiation damage in CeO2 irradiated with high-energy ions
Spring Meeting of the Physical Society of Japan, Osaka, Japan (Mar. 23, 2008).
N. Matsunami, M. Sataka, S. Okayasu, and M. Tazawa
Electronic sputtering of nitrides
2007 Fall Meeting, Japan Physical Society, Sapporo, Japan (Sep. 22, 2007).
A. Iwase
Ion irradiation induced ferromagnetism in FeRh alloys
The Doyama Symposium on Advanced Materials, Tokyo, Japan ( Sep. 6, 2007)
M. Sasase, K. Shimura, K. Yamaguchi, H. Yamamoto, S. Shamoto, and K. Hojou
Sputter etching effect of the substrate on the microstructure of β-FeSi2 thin film prepared by ion beam
sputter deposition method
17th International Vacuum Congress (IVC-17), Stockholm, Sweden (Jul. 3, 2007).

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JAEA-Review 2008-054

CHAPTER 9
Personnel and Committee

9.1

Personnel

9.2

Research Planning and Assessment Committee－ 137 －

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JAEA-Review 2008-054

9. 1

Personnel
Department of Research Reactor and Tandem Accelerator
Kiyonobu

Yamashita

Director

SuehiroTakeuchi

Deputy Director

YuichiTerakado

Manager of Administration Section

Department of Research Reactor and Tandem Accelerator
Tandem Accelerator Section (* General Manager )Scientific Staff
Masao

Sataka*AkihikoOsa

MakotoMatsudaTechnical Staff
Yoshihiro

Tsukihashi

SusumuHanashima

Shin-ichi

Abe

Nobuhiro

IshizakiTakamitsu Nakanoya
Hiroshi

Kabumoto

Masahiko

Nakamura

Ken-ichiKutsukake

Yoshinori

Otokawa

Takuhiro

Asozu

Entrusted Operators
Takahiro

YoshidaTakahiro

Usami

Takayuki

Ishiguro

Kazushi

Yamaguchi

HikaruNisugi

Nobuo

Seki

Teruo

Onodera(Apr. – Jul.)

Entrusted AssistantKenjiroObara

Department of Radiation Protection
Facility Radiation Control Section I
Kenji

YamaneTakashiNakazawa

KatsujiYasu－ 139 －

JAEA-Review 2008-054

HayatoHiragaDaisukeHigashi

Advanced Science Research Center
YoshihikoHatanoDirector

HiroshiIkezoeDeputy Director

Advanced Science Research Center
Research Group for Physics of Heavy Nuclei(* Group Leader)
Hiroari

Miyatake*

TetsuroIshii

Shin-ichi

Ichikawa

SatoshiChiba

ToshikiMaruyama

Shin-ichi

Mitsuoka

Katsuhisa

NishioHiroyuki

Koura

YutakaUtsunoTetsuyaSato

Takashi

Hashimoto(Post Doc.)

Hiroyuki

Makii(Post Doc.)

Daisuke

Nagae(Post Doc.)

Shintaro

Hashimoto(Student)

Hiroki

Sato(Student)

Advanced Science Research Center
Research Group for Nuclear chemistry of Superheavy Elements(* Group Leader)
Yuichiro

Nagame*Kazuaki

TsukadaIchiroNishinaka

MasatoAsaiAtsushiToyoshim(Post Doc.)

Yoshitaka

Kasamatsu(Post Doc.)

Yasuo

Ishii

(Student)

HayatoToume(Student)

Advanced Science Research Center
Research Group for Material Design under Extreme Conditions－ 140 －

JAEA-Review 2008-054

SatoruOkayasu

Hiroyuki

Sugai

NoritoIshikawa

Teruo

Kato

Nuclear Science and Engineering Directorate
Innovative Nuclear Science Research Group(* Group Leader )Masumi

Oshima*Hideo

HaradaHideki

IimuraMitsuoKoizumi

Sub Leader

Kazuyoshi Furutaka
Yuichi

Hatsukawa

FumitoKitatani

Shoji

Nakamura

YosukeToh

Atsushi

KimuraTadahiro

Kin(Post Doc.)

Nuclear Science and Engineering Directorate
Nuclear Data Center(* Group Leader )Jun-ichi

Katakura*

Keiichi

ShibataTokioFukahori

Akira

Ichikawa

Osamu

IwamotoNobuyuki

IwamotoSatoshi

KuniedaNaohiko

Otsuka(Apr. – Dec.)

Nuclear Science and Engineering Directorate
Research Group for Irradiation Field Materials( * Group Leader )Shiro

Jitsukawa*NariakiOkubo

DaijyuYamaki－ 141 －

JAEA-Review 2008-054

Quantum Beam Science Directorate
Laser Accelerator Group
Takehito

Hayakawa

Toshiyuki

ShizumaHigh Energy Accelerator Research Organization (KEK)
Institute of Particle and Nuclear Studies – Radioactive Nuclear Beams Project Group(* Group Leader )Physics Division IV
Hiroari

Miyatake*

Sun-ChanJeong

Masahiko

TanakaHironobu

Ishiyama

YutakaWatanabeNobuakiImai

Yoshikazu Hirayama
Yoshihide

Fuchi

Michihiro

OyaizuIchiroKatayama

Hirokane

Kawakami

Physics Division I
Shoji

SuzukiHigh Energy Accelerator Research Organization (KEK)
Accelerator Laboratory
Accelerator Division I
Shigeaki

Arai

MasashiOkada－ 142 －

JAEA-Review 2008-054

9. 2 Research Planning and Assessment Committee
Chairperson

Shigeru

Kubono(Professor, The University of Tokyo)

Vice Chairperson

Ken-ichiro Komaki(Professor, The University of Tokyo)

MemberKouichi

Hagino(Associate Professor, Tohoku University)

TadashiKambara(Senior Scientist, RIKEN*)

Kenji

Kimura(Professor, Kyoto University)

NoriakiMatsunami(Associate Professor, Nagoya University)

Motoharu Mizumoto(Special-appointment Professor, Tokyo Institute ofTechnology)

TetsuoNoro(Professor, Kyushu University)

Tsutomu

Ohtsuki(Associate Professor, Tohoku University)

Tadashi

Shimoda(Professor, Osaka University)

Yuichi

Hatsukawa(Quantum Beam Science Directorate, JAEA**)

HiroshiIkezoe(Deputy Director, Advanced Science Research Center,
JAEA)

Shiro

Jitsukawa(Nuclear Science and Engineering Directorate, JAEA)

Kazumasa Narumi(Advanced Science Research Center, JAEA)

Suehiro(Deputy Director, Dep. Research Reactor and Accelerator,

Takeuchi

JAEA)
Organizer

AkihikoOsa(Tandem Accelerator Section, JAEA)

Masao

Sataka(Tandem Accelerator Section, JAEA)* The Institute for Physical and Chemical Research** Japan Atomic Energy Agency－ 143 －

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JAEA-Review 2008-054

CHAPTER 10
Cooperative Researches andCommon Use Program in JAEA

10.1 Cooperative Researches List
10.2 Common Use Program in JAEA

－ 145 －

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JAEA-Review 2008-054

10. 1 Cooperative Researches List
Title

Contact Person & Organization

1. Process of structural change in light-water reactor fuelwith irradiation damage by fission products

Takeshi SONODA
Central Research Institute of ElectricPower Industry

2. Process of irradiation damage in nuclear reactor materials
with Fe base alloys

Akihiro IWASE
Osaka Prefecture University

3. Dynamic behavior of heavy ions in material

Kiyoshi KAWATSURA
Kyoto Institute of Technology

4. Study of nuclear deformation by Coulomb excitation andlifetime measurement

Masahiko SUGAWARA
Chiba Institute of Technology

5. Study of super-deformed state and high-spin shellstructure in A=30 region

Eiji IDEGUCHI
University of Tokyo

6. Coulomb excitation on neutron-rich Xe nuclei of fission
products

Sun-Chan JEONG
High Energy Accelerator Research
Organization

7. Nuclear spectroscopy using lasers for refractory elementisotope in Re region

Takayoshi HORIGUCHI
Hiroshima International University

8. Aqueous chemistry of super-heavy elements Rf and Db

Hisaaki KUDO
Niigata University

9. Alpha-gamma spectroscopy for super-heavy nuclei using
californium target

Keisuke SUEKI
University of Tsukuba

10. Development of electrochemical apparatus for single
atom chemistry

Atsushi SHINOHARA
Osaka University

11. Study of nuclear fission from excited states ofheavy-actinide nuclei

Akihiko YOKOYAMA
Kanazawa University

12. Study of nuclear structure in the region of A=180 nuclei
by the transfer reaction

Eiji IDEGUCHI
University of Tokyo

13. Experimental study of fusion barrier distribution forsuper-heavy element synthesis

Sun-Chan JEONG
High Energy Accelerator Research
Organization

14. Study of element synthesis in the universe via short-lived
nuclei

Hiroari MIYATAKEHigh Energy Accelerator Research
Organization－ 147 －

JAEA-Review 2008-054

10. 1 Cooperative Researches List (contd.)
Title

Contact Person & Organization

15. Search of unknown nuclei in neutron-rich lanthanide

Michihiro SHIBATA
Nagoya University

16. In-beam gamma-ray spectroscopy of super-heavy nuclei
using californium target

Toshiyuki KOUNOTokyo Institute of Technology

17. Development of spectrometer for in-beam gamma-ray
spectroscopy of super-heavy nuclei

Toshiyuki KOUNOTokyo Institute of Technology

18. Production of heavy elements by heavy-ion fusion
reaction using actinide targets and measurement of the decay
properties
19. Ion source development for the JAEA on line isotope
separator

Tsutomu OHTSUKI
Tohoku University
Sun-Chan JEONG
High Energy Accelerator Research
Organization

20. β-decay spectroscopy of nuclear spin polarized nuclei in theregion of132

SnYoshikazu HIRAYAMAHigh Energy Accelerator Research
Organization

21. Generation of polarized Cs and Ba isotope by using
tilted-foil method and measurement of nuclear magnetic
moment
22. Development for search of time-reversal symmetryKensaku MATSUTA
Osaka University
Jiro MURATA
Rikkyo University

violation using polarized nuclei
23. Measurement of the 8Li (α, n) 11B reaction cross section

Tomokazu FUKUDA
OsakaElectro-Communication

for astrophysical interest

University
24. Measurement of hyperfine field of111

Cd in thehigh-oriented pyrolytic graphite

Wataru SATO
Osaka University

25. Coulomb excitation of unstable nuclei

Nobuaki IMAIHigh Energy Accelerator Research
Organization

26. Diffusion study in super-ionic conducting materials using
the short-lived nuclei

Sun-Chan JEONG
High Energy Accelerator Research
Organization－ 148 －

JAEA-Review 2008-054

10. 2 Common Use Program in JAEA
Title

Contact Person & Organization

1. Radiation-induced magnetic transition in FeRh alloys

Akihiro IWASE
Osaka Prefecture University

2. Study on electronic structure and processes for highly
charged heavy-ions by zero-degree electron spectroscopy
3. Atomic structure and ion distribution in ion tracks inspinel irradiated with swift heavy ions

Kiyoshi KAWATSURA
Kyoto Institute of Technology
Kazuhiro YASUDA
Kyushu University

4. Study of decay properties of fission products using
JAEA-ISOL

Michihiro SHIBATA
Nagoya University

5. Effect of neutron transfer in heavy-ion fusion reaction

Yutaka WATANABEHigh Energy Accelerator Research
Organization

6. Production of radioactive-isotope tracers for chemistry ofheavy and super heavy elements

Shinichi GOTO
Niigata University

7. Systematic study of signature inversion and shapecoexistence in high-spin states of A=170-190 nuclei

X.H. Zhou
Institute of Modern Physics Chinese
Academy of Science

8. Electronic excitation effects on non-metals by high energy
heavy ions

Noriaki MATSUNAMI
Nagoya University

9. Measurement of hyperfine field in oxide magnetic materialusing gamma-ray perturbed angular correlation
10. Synthesis of water-soluble radioisotope-metallofullerenes

Wataru SATO
Osaka University
Keisuke SUEKI
University of Tsukuba－ 149 －

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