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Ishida, Tsuyoshi; Nakashima, Shinichi; Kondo, Shinji; Hayashibara, Kenichi; Yamada, Shigeki*; Okamoto, Ryo*; Nakamura, Hironobu
Dai-44-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2023/11
no abstracts in English
Akiyama, Yoichi; Shibanuma, So; Yanagisawa, Kenichi*; Yamada, Taichi; Suzuki, Kenta; Yoshida, Moeka; Ono, Takahiro; Kawabata, Kuniaki; Watanabe, Kaho; Morimoto, Kyoichi; et al.
JAEA-Review 2023-015, 60 Pages, 2023/09
JAEA-Review-2023-015.pdf:4.78MB
Naraha Center for Remote Control Technology Development (NARREC) was established in Japan Atomic Energy Agency to promote a decommissioning work of Fukushima Daiichi Nuclear Power Station (Fukushima Daiichi NPS). NARREC consists of a Full-scale Mock-up Test Building and Research Management Building. Various test facilities are installed in these buildings for the decommissioning work of Fukushima Daiichi NPS. These test facilities are intended to be used for various users, such as companies engaged in the decommissioning work, research and development institutions, educational institutions and so on. The number of NARREC facility uses was 84 in FY2021. We participated booth exhibitions and presentations on the decommissioning related events. Moreover, we also contributed to the development of human resources by supporting the 6th Creative Robot Contest for Decommissioning. As a new project, "Narahakko Children's Classroom" was implemented for elementary school students in Naraha Town. This report summarizes the activities of NARREC in FY2021, such as the utilization of facilities and equipment of NARREC, the development of remote-control technologies for supporting the decommissioning work, arrangement of the remote-control machines for emergency response, and training for operators by using the machines.
Ca cast doubt on a doubly magic 
CaChen, S.*; Browne, F.*; Doornenbal, P.*; Lee, J.*; Obertelli, A.*; Tsunoda, Yusuke*; Otsuka, Takaharu*; Chazono, Yoshiki*; Hagen, G.*; Holt, J. D.*; et al.
Physics Letters B, 843, p.138025_1 - 138025_7, 2023/08
Times Cited Count：1 Percentile：64.66(Astronomy & Astrophysics)Gamma decays were observed in 
Ca and 
Ca following quasi-free one-proton knockout reactions from 
Sc. For Ca, a 
ray transition was measured to be 1456(12) keV, while for Ca an indication for a transition was observed at 1115(34) keV. Both transitions were tentatively assigned as the 
decays. A shell-model calculation in a wide model space with a marginally modified effective nucleon-nucleon interaction depicts excellent agreement with experiment for 
level energies, two-neutron separation energies, and reaction cross sections, corroborating the formation of a new nuclear shell above the N = 34 shell. Its constituents, the 
and 
orbitals, are almost degenerate. This degeneracy precludes the possibility for a doubly magic Ca and potentially drives the dripline of Ca isotopes to 
Ca or even beyond.
Hirata, Sakiko*; Kusaka, Ryoji; Meiji, Shogo*; Tamekuni, Seita*; Okudera, Kosuke*; Hamada, Shoken*; Sakamoto, Chihiro*; Honda, Takumi*; Matsushita, Kosuke*; Muramatsu, Satoru*; et al.
Inorganic Chemistry, 62(1), p.474 - 486, 2023/01
Times Cited Count：0 Percentile：0.01(Chemistry, Inorganic & Nuclear)
island of inversion; First study of low-lying bound excited states in 
V and 
VElekes, Z.*; Juh
sz, M. M.*; Sohler, D.*; Sieja, K.*; Yoshida, Kazuki; Ogata, Kazuyuki*; Doornenbal, P.*; Obertelli, A.*; Achouri, N. L.*; Baba, Hidetada*; et al.
Physical Review C, 106(6), p.064321_1 - 064321_10, 2022/12
Times Cited Count：2 Percentile：49.92(Physics, Nuclear)The low-lying level structure of V and V was investigated for the first time. The neutron knockout reaction and inelastic proton scattering were applied for V while the neutron knock-out reaction provided the data for V. Four and five new transitions were determined for V and V, respectively. Based on the comparison to our shell-model calculations using the Lenzi-Nowacki-Poves-Sieja (LNPS) interaction, three of the observed rays for each isotope could be placed in the level scheme and assigned to the decay of the first 11/2
and 9/2 levels. The (
,
) excitation cross sections for V were analyzed by the coupled-channels formalism assuming quadrupole plus hexadecapole deformations. Due to the role of the hexadecapole deformation, V could not be unambiguously placed on the island of inversion.
neutron orbital and the 
shell closure in 
CaEnciu, M.*; Liu, H. N.*; Obertelli, A.*; Doornenbal, P.*; Nowacki, F.*; Ogata, Kazuyuki*; Poves, A.*; Yoshida, Kazuki; Achouri, N. L.*; Baba, Hidetada*; et al.
Physical Review Letters, 129(26), p.262501_1 - 262501_7, 2022/12
Times Cited Count：5 Percentile：65.23(Physics, Multidisciplinary)The one-neutron knockout from Ca was performed at 
230 MeV/nucleon combined with prompt spectroscopy. The momentum distributions corresponding to the removal of 
and 
neutrons were measured. The cross sections are consistent with a shell closure at the neutron number , found as strong as at 
and 
in Ca isotopes from the same observables. The analysis of the momentum distributions leads to a difference of the root-mean-square radii of the neutron 
and orbitals of 0.61(23) fm, in agreement with the modified-shell-model prediction of 0.7 fm suggesting that the large root-mean-square radius of the orbital in neutron-rich Ca isotopes is responsible for the unexpected linear increase of the charge radius with the neutron number.
Ca; Spectroscopy of 
K, Ca, and 
CaKoiwai, Takuma*; Wimmer, K.*; Doornenbal, P.*; Obertelli, A.*; Barbieri, C.*; Duguet, T.*; Holt, J. D.*; Miyagi, Takayuki*; Navrtil, P.*; Ogata, Kazuyuki*; et al.
Physics Letters B, 827, p.136953_1 - 136953_7, 2022/04
Times Cited Count：4 Percentile：74.12(Astronomy & Astrophysics)no abstracts in English
Cl isotopesLinh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Chen, S.*; Chung, L. X.*; Duguet, T.*; G
mez-Ramos, M.*; et al.
Physical Review C, 104(4), p.044331_1 - 044331_16, 2021/10
Times Cited Count：6 Percentile：63.69(Physics, Nuclear)no abstracts in English
Okumura, Takuma*; Azuma, Toshiyuki*; Bennet, D. A.*; Caradonna, P.*; Chiu, I.-H.*; Doriese, W. B.*; Durkin, M. S.*; Fowler, J. W.*; Gard, J. D.*; Hashimoto, Tadashi; et al.
IEEE Transactions on Applied Superconductivity, 31(5), p.2101704_1 - 2101704_4, 2021/08
Times Cited Count：1 Percentile：10.62(Engineering, Electrical & Electronic)A superconducting transition-edge sensor (TES) microcalorimeter is an ideal X-ray detector for experiments at accelerator facilities because of good energy resolution and high efficiency. To study the performance of the TES detector with a high-intensity pulsed charged-particle beam, we measured X-ray spectra with a pulsed muon beam at the Japan Proton Accelerator Research Complex (J-PARC) in Japan. We found substantial temporal shifts of the X-ray energy correlated with the arrival time of the pulsed muon beam, which was reasonably explained by pulse pileup due to the incidence of energetic particles from the initial pulsed beam.
X raysOkumura, Takuma*; Azuma, Toshiyuki*; Bennet, D. A.*; Caradonna, P.*; Chiu, I. H.*; Doriese, W. B.*; Durkin, M. S.*; Fowler, J. W.*; Gard, J. D.*; Hashimoto, Tadashi; et al.
Physical Review Letters, 127(5), p.053001_1 - 053001_7, 2021/07
Times Cited Count：15 Percentile：80.44(Physics, Multidisciplinary)We observed electronic X rays emitted from muonic iron atoms using a superconducting transition-edge-type sensor microcalorimeter. The energy resolution of 5.2 eV in FWHM allowed us to observe the asymmetric broad profile of the electronic characteristic 
and 
X rays together with the hypersatellite X rays around 6 keV. This signature reflects the time-dependent screening of the nuclear charge by the negative muon and the 
-shell electrons, accompanied by electron side-feeding. Assisted by a simulation, this data clearly reveals the electronic - and -shell hole production and their temporal evolution during the muon cascade process.
Ca from direct reactionsBrowne, F.*; Chen, S.*; Doornenbal, P.*; Obertelli, A.*; Ogata, Kazuyuki*; Utsuno, Yutaka; Yoshida, Kazuki; Achouri, N. L.*; Baba, Hidetada*; Calvet, D.*; et al.
Physical Review Letters, 126(25), p.252501_1 - 252501_7, 2021/06
Times Cited Count：10 Percentile：74.2(Physics, Multidisciplinary)Direct proton-knockout reactions of Sc were studied at the RIKEN Radioactive Isotope Beam Factory. Populated states of Ca were investigated through -ray and invariant-mass spectroscopy. Level energies were calculated from the nuclear shell model employing a phenomenological inter-nucleon interaction. Theoretical cross sections to states were calculated from distorted-wave impulse approximation estimates multiplied by the shell model spectroscopic factors. Despite the calculations showing a significant amplitude of excited neutron configurations in the ground-state of Sc, valence proton removals populated predominantly the ground-state of Ca. This counter-intuitive result is attributed to pairing effects leading to a dominance of the ground-state spectroscopic factor. Owing to the ubiquity of the pairing interaction, this argument should be generally applicable to direct knockout reactions from odd-even to even-even nuclei.
Ar by the (,2) reactionJuhsz, M. M.*; Elekes, Z.*; Sohler, D.*; Utsuno, Yutaka; Yoshida, Kazuki; Otsuka, Takaharu*; Ogata, Kazuyuki*; Doornenbal, P.*; Obertelli, A.*; Baba, Hidetada*; et al.
Physics Letters B, 814, p.136108_1 - 136108_8, 2021/03
Times Cited Count：5 Percentile：63.69(Astronomy & Astrophysics)The nuclear structure of Ar was studied by the (,2) reaction using -ray spectroscopy for the bound and unbound states. Comparing the results to our shell-model calculations, two bound and six unbound states were established. The low cross sections populating the two bound states of Ar could be interpreted as a clear signature for the presence of significant sub-shell closures at neutron numbers 32 and 34 in argon isotopes.
= 32 shell closure below calcium; Low-lying structure of 
ArCort
s, M. L.*; Rodriguez, W.*; Doornenbal, P.*; Obertelli, A.*; Holt, J. D.*; Menndez, J.*; Ogata, Kazuyuki*; Schwenk, A.*; Shimizu, Noritaka*; Simonis, J.*; et al.
Physical Review C, 102(6), p.064320_1 - 064320_9, 2020/12
Times Cited Count：11 Percentile：78.75(Physics, Nuclear)Low-lying excited states in the = 32 isotope Ar were investigated by in-beam -ray spectroscopy following proton- and neutron-knockout, multinucleon removal, and proton inelastic scattering at the RIKEN Radioactive Isotope Beam Factory. The energies of the two previously reported transitions have been confirmed, and five additional states are presented for the first time, including a candidate for a 3 state. The level scheme built using coincidences was compared to shell-model calculations in the 
model space and to 
predictions based on chiral two- and three-nucleon interactions. Theoretical proton- and neutron-knockout cross sections suggest that two of the new transitions correspond to 2
states, while the previously proposed 4
state could also correspond to a 2 state.
= 40 isotones towards Ca; First spectroscopy of 
TiCorts, M. L.*; Rodriguez, W.*; Doornenbal, P.*; Obertelli, A.*; Holt, J. D.*; Lenzi, S. M.*; Menndez, J.*; Nowacki, F.*; Ogata, Kazuyuki*; Poves, A.*; et al.
Physics Letters B, 800, p.135071_1 - 135071_7, 2020/01
Times Cited Count：31 Percentile：96.48(Astronomy & Astrophysics)Excited states in the = 40 isotone Ti were populated via the 
V(,
)Ti reaction at 200 MeV/nucleon at the Radioactive Isotope Beam Factory and studied using -ray spectroscopy. The energies of the 
and 
transitions, observed here for the first time, indicate a deformed Ti ground state. These energies are increased compared to the neighboring 
Cr and 
Fe isotones, suggesting a small decrease of quadrupole collectivity. The present measurement is well reproduced by large-scale shell-model calculations based on effective interactions, while ab initio and beyond mean-field calculations do not yet reproduce our findings.
Ca corroborates arising 
neutron magic numberChen, S.*; Lee, J.*; Doornenbal, P.*; Obertelli, A.*; Barbieri, C.*; Chazono, Yoshiki*; Navrtil, P.*; Ogata, Kazuyuki*; Otsuka, Takaharu*; Raimondi, F.*; et al.
Physical Review Letters, 123(14), p.142501_1 - 142501_7, 2019/10
Times Cited Count：49 Percentile：92.61(Physics, Multidisciplinary)no abstracts in English
Nakajima, Kenji; Harjo, S.; Yamada, Norifumi*; Oikawa, Kenichi; Kajimoto, Ryoichi
JAEA-Review 2018-032, 43 Pages, 2019/02
JAEA-Review-2018-032.pdf:9.78MB
A series of meetings to discuss future neutron/muon sources and instruments at Materials and Life Science Experimental Facility (MLF) in Japan Proton Accelerator Research Complex (J-PARC) has been held since 2017. Each of the neutron instrument groups in MLF proposed required features for future instruments, while addressing issues of the current instruments and facilities. This report compiles the presentation materials presented by the neutron instrument groups in the meetings to help future discussion for the coming MLF.
Kamikubota, Norihiko*; Yamada, Shuei*; Sato, Kenichiro*; Kikuzawa, Nobuhiro; Yamamoto, Noboru*; Yoshida, Susumu*; Nemoto, Hiroyuki*
Proceedings of 16th International Conference on Accelerator and Large Experimental Physics Control Systems (ICALEPCS 2017) (Internet), p.1470 - 1473, 2018/01
no abstracts in English
Nakajima, Kenji; Kawakita, Yukinobu; Ito, Shinichi*; Abe, Jun*; Aizawa, Kazuya; Aoki, Hiroyuki; Endo, Hitoshi*; Fujita, Masaki*; Funakoshi, Kenichi*; Gong, W.*; et al.
Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12
The neutron instruments suite, installed at the spallation neutron source of the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), is reviewed. MLF has 23 neutron beam ports and 21 instruments are in operation for user programs or are under commissioning. A unique and challenging instrumental suite in MLF has been realized via combination of a high-performance neutron source, optimized for neutron scattering, and unique instruments using cutting-edge technologies. All instruments are/will serve in world-leading investigations in a broad range of fields, from fundamental physics to industrial applications. In this review, overviews, characteristic features, and typical applications of the individual instruments are mentioned.
Kubota, Ryuzaburo; Koyama, Kazuya*; Moriwaki, Hiroyuki*; Yamada, Yumi*; Shimakawa, Yoshio*; Suzuki, Toru; Kawada, Kenichi; Kubo, Shigenobu; Yamano, Hidemasa
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 10 Pages, 2017/04
This paper describes an analysis study on the initiating phase of the ATWS events with SAS4A in order to confirm the appropriateness of the core design for the medium-scale SFR (750MWe-1765MWt). Not using a conventional lumping method that multiple fuel sub-assemblies having a similar characteristic were assigned to one channel (representing fuel assembly in SAS4A), each channel represents only the sub-assemblies of identical operating condition. In addition, the detailed power and reactivity distribution were set reflecting the change of insertion position of control rods. Applying these detailed analysis conditions, the SAS4A analyses were performed for unprotected loss-of-flow (ULOF) and unprotected transient overpower (UTOP) during both of the nominal power and the partial power operation. As a result, more proper event progression including incoherency of events especially fuel dispersion after fuel failure was successfully evaluated and then this analysis study suggested that the power excursion with prompt criticality leading to large mechanical energy release can be prevented in the initiating phase of the current design.
Shimizu, Kenichi*; Koike, Yuki*; Yamada, Taiki*; Oharada, Kazuya*; Tanaka, Keisuke*; Shobu, Takahisa
Zairyo, 65(9), p.657 - 664, 2016/09
The internal stress in crystalline thermoplastics, polyphenylene sulphide (PPS), reinforced by carbon fibers of 30 mass% was measured by the diffraction method using synchrotron with energy of 12.3 keV. The stress in the matrix was determined by the sin2psi method with side-inclination optics of transmitted X-ray diffractions. Using skin-layer strips cut parallel, perpendicular and 45 degree to the molding direction of the injection molded plates, the matrix stress was measured under the uniaxial applied stress. The experimental values were at least qualitatively agreed with the prediction derived based on micromechanics. The quantitative difference between experiment and prediction is mainly due to the neglect of the distribution of fiber orientations in the micromechanics prediction. These residual stresses were caused by the mismatch of the thermal expansion coefficient between matrix and fibers.
