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self-conjugate nuclei in 
no-core Monte Carlo shell model calculations with nonlocal 
interactionsAbe, Takashi*; Maris, P.*; Otsuka, Takaharu*; Shimizu, Noritaka*; Utsuno, Yutaka; Vary, J. P.*
Physical Review C, 104(5), p.054315_1 - 054315_22, 2021/11
Times Cited Count：9 Percentile：76.16(Physics, Nuclear)no abstracts in English
Dimitriou, P.*; Basunia, S*; Bernstein, L.*; Chen, J.*; Elekes, Z.*; Huang, X.*; Hurst, A.*; Iimura, Hideki; Jain, A. K.*; Kelley, J.*; et al.
EPJ Web of Conferences, 239, p.15004_1 - 15004_4, 2020/09
Times Cited Count：0 Percentile：0.1(Nuclear Science & Technology)The Evaluated Nuclear Structure Data File (ENSDF) includes the most extensive and comprehensive set of nuclear structure and decay data evaluations performed by the international network of Nuclear Structure and Decay Data evaluators (NSDD) under the auspices of the IAEA. In this report we describe some of the recent NSDD activities and provide future perspectives.
Sonoda, Tetsu*; Katayama, Ichiro*; Wada, Michiharu*; Iimura, Hideki; Sonnenschein, V.*; Iimura, Shun*; Takamine, Aiko*; Rosenbusch, M.*; Kojima, Takao*; Ahn, D. S.*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2019(11), p.113D02_1 - 113D02_12, 2019/11
Times Cited Count：1 Percentile：11.61(Physics, Multidisciplinary)An in-flight separator, BigRIPS, at RIBF in RIKEN provides each experiment with specific nuclides separated from many nuclides produced by projectile fragmentation or in-flight fission. In this process, nuclides other than separated ones are discarded on the slits in BigRIPS, although they include many nuclides interested from the view point of nuclear structure. In order to extract these nuclides for parasitic experiments, we are developing a method using laser ion-source (PALIS). A test experiment with 
Se beam from RIBF has been performed by using a gas cell set in BigRIPS. Unstable nuclides around 
Se were stopped in the gas cell in accordance with a calculation using LISE code. The stopping efficiency has been estimated to be about 30%. As a next step, we will establish the technique for extracting reaction products from the gas cell.
Ni from the (
,
) reactionElekes, Z.*; Kripk
, 
*; Sohler, D.*; Sieja, K.*; Ogata, Kazuyuki*; Yoshida, Kazuki; Doornenbal, P.*; Obertelli, A.*; Authelet, G.*; Baba, Hidetada*; et al.
Physical Review C, 99(1), p.014312_1 - 014312_7, 2019/01
Times Cited Count：10 Percentile：64.15(Physics, Nuclear)The nuclear structure of the Ni nucleus was investigated by (,) reaction using a NaI(Tl) array to detect the deexciting prompt 
rays. A new transition with an energy of 2227 keV was identified by 
and 
coincidences. Our shell-model calculations using the Lenzi, Nowacki, Poves, and Sieja interaction produced good candidates for the experimental proton hole states in the observed energy region, and the theoretical cross sections showed good agreement with the experimental values. Although we could not assign all the experimental states to the theoretical ones unambiguously, the results are consistent with a reasonably large Z = 28 shell gap for nickel isotopes in accordance with previous studies.
Sonoda, Tetsu*; Iimura, Hideki; Reponen, M.*; Wada, Michiharu*; Katayama, Ichiro*; Sonnenschein, V.*; Takamatsu, Takahide*; Tomita, Hideki*; Kojima, Takao*
Nuclear Instruments and Methods in Physics Research A, 877, p.118 - 123, 2018/01
Times Cited Count：4 Percentile：38.58(Instruments & Instrumentation)In order to produce low-energy RI beams at RIKEN RIBF, a laser ion source, PALIS, is under construction. This ion source is based on resonance ionization of RI atoms captured in Ar gas. Because the ion source is located 70m away from lasers, we have developed an optical system for laser beam transport. This system can be controlled remotely when the ion source is not accessible because of high radiation level. The position of laser beam after transport is reasonably stable, and the transport efficiency is about 50%.
Department of Research Reactor and Tandem Accelerator
JAEA-Review 2016-025, 101 Pages, 2016/12
JAEA-Review-2016-025.pdf:7.86MB
The JAEA-Tokai tandem accelerator complex has been used in various research fields such as nuclear science and material science by researchers not only of JAEA but also from universities, research institutes and industrial companies. This annual report covers developments of accelerators and research activities carried out using the tandem accelerator and superconducting booster from April 1, 2013 to March 31, 2014. Thirty-one summary reports 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. This report also lists publications, meetings, personnel, committee members, cooperative researches and common use programs.
in-beam -ray spectroscopyTakeuchi, Satoshi*; Steppenbeck, D.*; Utsuno, Yutaka
Nihon Butsuri Gakkai-Shi, 70(7), p.535 - 539, 2015/07
no abstracts in English
Togashi, Tomoaki*; Shimizu, Noritaka*; Utsuno, Yutaka; Otsuka, Takaharu*; Homma, Michio*
Physical Review C, 91(2), p.024320_1 - 024320_12, 2015/02
Times Cited Count：25 Percentile：82.61(Physics, Nuclear)We perform large-scale shell-model calculations for unnatural-parity high-spin states in neutron-rich Cr and Fe isotopes with 
= 31-35. The excitation energies of the 
states for those odd-mass nuclei sharply decrease with the neutron number, which attracts much interest. In this study, we calculate those unnatural-parity states systematically using an effective interaction comprised of existing ones plus minimal modifications. The calculated energy levels excellently agree with experimental data. The deformations of those isotopes are analysed by using the wave functions obtained by the shell-model calculations. We show that prolate deformation dominates this region, contrary to the previous suggestion based on the isomeric level. It is demonstrated that the sharp decrease of the levels occurs due to the rising of the Fermi surface, but not due to the evolution of the 
single-particle level as suggested previously.
Utsuno, Yutaka; Shimizu, Noritaka*; Otsuka, Takaharu*; Yoshida, Toru*; Tsunoda, Yusuke*
Physical Review Letters, 114(3), p.032501_1 - 032501_5, 2015/01
Times Cited Count：37 Percentile：85.46(Physics, Multidisciplinary)In usual even-even nuclei, 
, 
, 
states are known to be connected via strong 
transitions. The recently observed 
state in the neutron-rich nucleus 
S has a strongly hindered transition to the state. We report the origin of this strong hindrance in this paper. While shell-model calculations reproduce the hindrance, their many-body wave functions are too complicated for one to understand the nature. In this study, we introduce a novel method to obtain wave functions in the intrinsic frame by performing the variation after angular-momentum projection. The , states are dominated by the usual 
state, whereas for the 
level the 
state is lower than state, which causes the hindrance. We also account for similar hindrance in 
S in this framework. The 
level is the lightest-mass high-
isomer ever found.
La fed by the Ce beta-decayIimura, Hideki; Asai, Masato; Ichikawa, Shinichi; Katakura, Junichi; Magara, Masaaki; Osa, Akihiko; Oshima, Masumi; Shinohara, Nobuo; Yamamoto, Hiroshi*
European Physical Journal A, 23(1), p.33 - 39, 2005/01
Times Cited Count：2 Percentile：23.55(Physics, Nuclear)The low-lying levels in La have been studied through the 
-decay of Ce (
= 29 s) produced by bombarding a 
Mo target with a 185-MeV 
Cl beam. Reaction products were on-line mass-separated, and -ray singles and - coincidence measurements were performed. Conversion electrons were also measured and multipolarities of transitions have been derived. A half-life of an excited state was determined by the - delayed coincidence technique. The level scheme obtained has been compared with calculations based on the Nilsson model.
S and the proton-neutron coupling of intruder statesMason, P.*; M
rginean, N.*; Lenzi, S. M.*; Ionescu-Bujor, M.*; Della Vedova, F.*; Napoli, D. R.*; Otsuka, Takaharu*; Utsuno, Yutaka; Nowacki, F.*; Axiotis, M.*; et al.
Physical Review C, 71(1), p.014316_1 - 014316_8, 2005/01
Times Cited Count：25 Percentile：80.41(Physics, Nuclear)no abstracts in English
Igashira, Masayuki*; Shibata, Keiichi; Takano, Hideki*; Yamano, Naoki*; Matsunobu, Hiroyuki*; Kitao, Kensuke*; Katakura, Junichi; Nakagawa, Tsuneo; Hasegawa, Akira; Iwasaki, Tomohiko*; et al.
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(1), p.128 - 139, 2004/03
no abstracts in English
DyHayakawa, Takehito; Toh, Yosuke; Oshima, Masumi; Matsuda, Makoto; Hatsukawa, Yuichi; Shizuma, Toshiyuki; Katakura, Junichi; Iimura, Hideki; Mitarai, Shiro*; Zhang, Y.*; et al.
Physical Review C, 68(6), p.067303_1 - 067303_4, 2003/12
Times Cited Count：2 Percentile：21.31(Physics, Nuclear)no abstracts in English
SeHayakawa, Takehito; Toh, Yosuke; Oshima, Masumi; Osa, Akihiko; Koizumi, Mitsuo; Hatsukawa, Yuichi; Utsuno, Yutaka; Katakura, Junichi; Matsuda, Makoto; Morikawa, Tsuneyasu*; et al.
Physical Review C, 67(6), p.064310_1 - 064310_6, 2003/06
Times Cited Count：17 Percentile：69.91(Physics, Nuclear)no abstracts in English
Re isomeric stateHayakawa, Takehito; Shizuma, Toshiyuki; Yamauchi, Toshihiko; Minehara, Eisuke; Arisawa, Takashi
Nuclear Physics A, 718, p.665c - 667c, 2003/05
no abstracts in English
GdHayakawa, Takehito; Toh, Yosuke; Oshima, Masumi; Matsuda, Makoto; Hatsukawa, Yuichi; Shinohara, Nobuo; Iimura, Hideki; Shizuma, Toshiyuki; Zhang, Y.*; Sugawara, Masahiko*; et al.
Physics Letters B, 551(1-2), p.79 - 85, 2003/01
Times Cited Count：10 Percentile：55.62(Astronomy & Astrophysics)no abstracts in English
band in DyHayakawa, Takehito; Toh, Yosuke; Oshima, Masumi; Matsuda, Makoto; Hatsukawa, Yuichi; Katakura, Junichi; Iimura, Hideki; Shizuma, Toshiyuki; Mitarai, Shiro*; Sugawara, Masahiko*; et al.
European Physical Journal A, 15(3), p.299 - 302, 2002/11
Times Cited Count：9 Percentile：48.02(Physics, Nuclear)no abstracts in English
isomeric decaysShizuma, Toshiyuki; Shimizu, Yoshifumi*; Hayakawa, Takehito
Journal of Nuclear Science and Technology, 39(11), p.1137 - 1141, 2002/11
Times Cited Count：4 Percentile：29.25(Nuclear Science & Technology)We have systematically investigated the highly -forbidden transitions observed in the Hf, W and Os region, using the -tunneling model in which low- and high- states interact through a process of the quantum tunneling. In the present study, we have analyzed -forbidden transitions recently observed. The measured hindrance factors are compared with the values calculated using the -tunneling model. We have also investigated isotope dependences of tunneling probabilities particularly for neutron-rich nuclei.
Katakura, Junichi; Kitao, Kensuke*
Nuclear Data Sheets, 97(3-4), p.765 - 926, 2002/11
no abstracts in English
Soukhovitskij, E. Sh.*; Chiba, Satoshi
Journal of Nuclear Science and Technology, 39(Suppl.2), p.697 - 702, 2002/08
Coupled-channels optical model approach built on the wave functions of the soft-rotator nuclear Hamiltonian is applied for the self-consistent analyses of the low-lying collective nuclear level structure and nucleon interaction with even-even nuclei in a wide 
- mass region. It succeeds to describe available experimental data and 
- transitions with reasonable accuracy. Along with the account of the global optical potential form and relativistic kinematics, present method was proved to be a powerful tool for studies of nucleon-induced reaction data.
