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Tanabe, Kosuke*; Komeda, Masao; Toh, Yosuke; Kitamura, Yasunori*; Misawa, Tsuyoshi*
Nihon Genshiryoku Gakkai-Shi ATOMO
, 67(3), p.198 - 202, 2025/03
no abstracts in English
Cf rotation method with a water Cherenkov neutron detectorTanabe, Kosuke*; Komeda, Masao; Toh, Yosuke; Kitamura, Yasunori*; Misawa, Tsuyoshi*; Tsuchiya, Kenichi*; Sagara, Hiroshi*
Scientific Reports (Internet), 14, p.18828_1 - 18828_10, 2024/08
Times Cited Count：0 Percentile：0.00(Multidisciplinary Sciences)Ichikawa, Tsubasa*; Hakoshima, Hideaki*; Inui, Koji*; Ito, Kosuke*; Matsuda, Ryo*; Mitarai, Kosuke*; Miyamoto, Koichi*; Mizukami, Wataru*; Mizuta, Kaoru*; Mori, Toshio*; et al.
Nature Reviews Physics (Internet), 6(6), p.345 - 347, 2024/06
Times Cited Count：7 Percentile：99.15(Physics, Applied)
He spin filter and small-angle X-ray scatteringRyoki, Akiyuki*; Watanabe, Fumi*; Okudaira, Takuya*; Takahashi, Shingo*; Oku, Takayuki; Hiroi, Kosuke; Motokawa, Ryuhei; Nakamura, Yo*
Journal of Chemical Physics, 160(11), p.114907_1 - 114907_9, 2024/03
Times Cited Count：2 Percentile：42.16(Chemistry, Physical)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：3 Percentile：28.83(Chemistry, Inorganic & Nuclear)Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
Times Cited Count：7 Percentile：74.40(Nuclear Science & Technology)In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.
Sasada, Seiji*; Takahashi, Yoshihito*; Takeuchi, Keisuke*; Hiroi, Kosuke; Su, Y. H.; Shinohara, Takenao; Watanabe, Kenichi*; Uritani, Akira*
Japanese Journal of Applied Physics, 61(4), p.046004_1 - 046004_8, 2022/03
Times Cited Count：0 Percentile：0.00(Physics, Applied)Sasada, Seiji*; Hiroi, Kosuke; Osanai, Kenta*; Shinohara, Takenao; Watanabe, K.*; Uritani, Akira*
Japanese Journal of Applied Physics, 60(12), p.126003_1 - 126003_6, 2021/12
Times Cited Count：4 Percentile：24.33(Physics, Applied)Komeda, Masao; Toh, Yosuke; Tanabe, Kosuke*; Kitamura, Yasunori*; Misawa, Tsuyoshi*
Annals of Nuclear Energy, 159, p.108300_1 - 108300_8, 2021/09
Times Cited Count：4 Percentile：40.86(Nuclear Science & Technology)
) reaction at 12, 20, and 30 MeVPatwary, M. K. A*; Kin, Tadahiro*; Aoki, Katsumi*; Yoshinami, Kosuke*; Yamaguchi, Masaya*; Watanabe, Yukinobu*; Tsukada, Kazuaki; Sato, Nozomi*; Asai, Masato; Sato, Tetsuya; et al.
Journal of Nuclear Science and Technology, 58(2), p.252 - 258, 2021/02
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)While designing deuteron accelerator neutron sources for radioisotopes production, nuclear data for light elements such as Li, Be, and C have been systematically measured in the deuteron energy range from a few MeV to around 50 MeV. Currently, the experimental data available on double-differential thick-target neutron yields (DDTTNYs) is insufficient, especially for deuteron energies between 18 and 33 MeV. In this study, we measured the DDTTNYs of () reactions on 
C target for incident deuteron energies of 12, 20, and 30 MeV using the multiple-foils activation method to improve nuclear data insufficiency. We applied the GRAVEL code for the unfolding process to derive the DDTTNYs. The results were compared with the calculation by DEURACS. The present data were also used to confirm the systematics of the differential neutron yields at 0
and total neutron yield per incident deuteron in the wide range of deuteron energy.
Al
GaO
scintillators by gamma-ray-induced positron annihilation lifetime spectroscopyFujimori, Kosuke*; Kitaura, Mamoru*; Taira, Yoshitaka*; Fujimoto, Masaki*; Zen, H.*; Watanabe, Shinta*; Kamada, Kei*; Okano, Yasuaki*; Kato, Masahiro*; Hosaka, Masahito*; et al.
Applied Physics Express, 13(8), p.085505_1 - 085505_4, 2020/08
Times Cited Count：6 Percentile：30.34(Physics, Applied)To clarify the existence of cation vacancies in Ce-doped GdAlGaO (Ce:GAGG) scintillators, we performed gamma-ray-induced positron annihilation lifetime spectroscopy (GiPALS). GiPAL spectra of GAGG and Ce:GAGG comprised two exponential decay components, which were assigned to positron annihilation at bulk and defect states. By an analogy with Ce:YAl
O, the defect-related component was attributed to Al/Ga-O divacancy complexes. This component was weaker for Ce, Mg:GAGG, which correlated with the suppression of shallow electron traps responsible for phosphorescence. Oxygen vacancies were charge compensators for Al/Ga vacancies. The lifetime of the defect-related component was significantly changed by Mg co-doping. This was understood by considering aggregates of Mg
ions at Al/Ga sites with oxygen vacancies, which resulted in the formation of vacancy clusters.
as a source of atmospheric IWatanabe, Kosuke*; Matsuda, Shohei; Cuevas, C. A.*; Saiz-Lopez, A.*; Yabushita, Akihiro*; Nakano, Yukio*
ACS Earth and Space Chemistry (Internet), 3(4), p.669 - 679, 2019/04
Times Cited Count：11 Percentile：46.78(Chemistry, Multidisciplinary)The photooxidation of aqueous iodide ions (I
) at sea surface results in the emission of gaseous iodine molecules (I
) into the atmosphere. It plays a certain role in the transport of iodine from ocean to the atmosphere in the natural cycle of iodine. In this study, we determined the photooxidation parameters, the molar absorption coefficient (
(
)) and the photooxidative quantum yields (
()) of I, in the range of 290-500 nm. Through the investigation of the influence of pH and dissolved oxygen (DO) on (), the subsequent emission rates of I following the photooxidation of I in deionized water solution (pH 5.6, DO 7.8 mg L
) and artificial seawater solution (pH 8.0, DO 7.0 mg L) were estimated. A global chemistry-climate model employed herein to assess the I ocean emission on a global scale indicated that the photooxidation of I by solar light can enhance the atmospheric iodine budget by up to 
8% over some oceanic regions.
= 100 with a multireflection time-of-flight mass spectrographIto, Yuta*; Schury, P.*; Wada, Michiharu*; Arai, Fumiya*; Haba, Hiromitsu*; Hirayama, Yoshikazu*; Ishizawa, Satoshi*; Kaji, Daiya*; Kimura, Sota*; Koura, Hiroyuki; et al.
Physical Review Letters, 120(15), p.152501_1 - 152501_6, 2018/04
Times Cited Count：66 Percentile：92.56(Physics, Multidisciplinary)Masses of 
Es, 
Fm and the transfermium nuclei 
Md, and 
No, produced by hot- and cold-fusion reactions, in the vicinity of the deformed 
neutron shell closure, have been directly measured using a multi-reflection time-of-flight mass spectrograph. The masses of Es and 
Md were measured for the first time. Using the masses of 
Md as anchor points for 
decay chains, the masses of heavier nuclei, up to 
Bh and 
Mt, were determined. These new masses were compared with theoretical global mass models and demonstrated to be in good agreement with macroscopic-microscopic models in this region. The empirical shell gap parameter 
derived from three isotopic masses was updated with the new masses and corroborate the existence of the deformed neutron shell closure for Md and Lr.
Tanaka, Taiki*; Narikiyo, Yoshihiro*; Morita, Kosuke*; Fujita, Kunihiro*; Kaji, Daiya*; Morimoto, Koji*; Yamaki, Sayaka*; Wakabayashi, Yasuo*; Tanaka, Kengo*; Takeyama, Mirei*; et al.
Journal of the Physical Society of Japan, 87(1), p.014201_1 - 014201_9, 2018/01
Times Cited Count：23 Percentile：75.18(Physics, Multidisciplinary)Excitation functions of quasielastic scattering cross sections for the 
Ca + 
Pb, 
Ti + Pb, and Ca + 
Cm reactions were successfully measured by using the gas-filled recoil-ion separator GARIS. Fusion barrier distributions were extracted from these data, and compared with the coupled-channels calculations. It was found that the peak energies of the barrier distributions for the Ca + Pb and Ti + Pb systems coincide with those of the 2n evaporation channel cross sections for the systems, while that of the Ca + Cm is located slightly below the 4n evaporation ones. This results provide us helpful information to predict the optimum beam energy to synthesize superheavy nuclei.
Mamiya, Hiroaki*; Oba, Yojiro; Terada, Noriki*; Watanabe, Norimichi*; Hiroi, Kosuke; Shinohara, Takenao; Oikawa, Kenichi
Scientific Reports (Internet), 7(1), p.15516_1 - 15516_8, 2017/11
Times Cited Count：4 Percentile：20.01(Multidisciplinary Sciences)no abstracts in English
Schury, P.*; Wada, Michiharu*; Ito, Yuta*; Kaji, Daiya*; Haba, Hiromitsu*; Hirayama, Yoshikazu*; Kimura, Sota*; Koura, Hiroyuki; MacCormick, M.*; Miyatake, Hiroari*; et al.
Nuclear Instruments and Methods in Physics Research B, 407, p.160 - 165, 2017/06
Times Cited Count：16 Percentile：79.63(Instruments & Instrumentation)Various isotopes of Ac, Ra, Fr, and Rn were produced by fusion-evaporation reactions using a Ca beam. The energetic ions were stopped in and extracted from a helium gas cell. The extracted ions were identified using a multi-reflection time-of-fight mass spectrograph. In all cases, it was observed that the predominant charge state for the extracted ions, including the alkali Fr, was 2+.
Matsuda, Kosuke*; Muramatsu, Ken*; Muta, Hitoshi*; Sato, Hiroyuki; Nishida, Akemi; Ohashi, Hirofumi; Itoi, Tatsuya*; Takada, Tsuyoshi*; Hida, Takenori*; Tanabe, Masayuki*; et al.
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 7 Pages, 2017/04
This paper proposes a set of procedures for accident sequence analysis in seismic PRAs of HTGRs that can consider the unique accident progression characteristics of HTGRs. Main features of our proposed procedure are as follows: (1) Systematic analysis techniques including Master Logic Diagrams are used to ensure reasonable completeness in identification of initiating events and classification of accident sequences, (2) Information on factors that govern the accident progression and source terms are effectively reflected to the construction of event trees for delineation of accident sequences, and (3) Frequency quantification of seismically-initiated accident sequence frequencies that involve multiplepipe ruptures are made with the use of the Direct Quantification of Fault Trees by Monte Carlo (DQFM) method by a computer code SECOM-DQFM.
-ray and neutron energy for area monitoring system in the IFMIF/EVEDA accelerator buildingTakahashi, Hiroki; Maebara, Sunao; Sakaki, Hironao; Hirabayashi, Keiichi*; Hidaka, Kosuke*; Shigyo, Nobuhiro*; Watanabe, Yukinobu*; Sagara, Kenshi*
Fusion Engineering and Design, 87(7-8), p.1235 - 1238, 2012/08
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)The Engineering Validation of the IFMIF/EVEDA prototype accelerator, up to 9 MeV by supplying the deuteron beam of 125 mA, will be performed at the BA site in Rokkasho. A design of this area monitoring system, comprising of Si semiconductors and ionization chambers for covering wide energy spectrum of -rays and He counters for neutrons, is now in progress. To establish an applicability of this monitoring system, photon and neutron energies have to be suppressed to the detector ranges of 1.5 MeV and 15 MeV, respectively. For this purpose, the reduction of neutron and photon energies throughout shield of water in a beam dump and concrete layer is evaluated by PHITS code, using the experimental data of neutron source spectra. In this article, a similar model using the beam dump structure and the position with a degree of leaning for concrete wall in the accelerator vault is used, and their energy reduction including the air is evaluated.
-ray and neutron area monitoring system for the IFMIF/EVEDA accelerator buildingTakahashi, Hiroki; Maebara, Sunao; Kojima, Toshiyuki; Kubo, Takashi; Sakaki, Hironao; Takeuchi, Hiroshi; Shidara, Hiroyuki; Hirabayashi, Keiichi*; Hidaka, Kosuke*; Shigyo, Nobuhiro*; et al.
Fusion Engineering and Design, 86(9-11), p.2795 - 2798, 2011/10
Times Cited Count：2 Percentile：17.59(Nuclear Science & Technology)In the IFMIF/EVEDA accelerator, the engineering validation up to 9 MeV by employing the deuteron beam of 125 mA are planning at the BA site in Rokkasho, Aomori, Japan, the personnel protection system (PPS) is indispensable. The PPS inhibit the beam by receiving the interlock signal from the -ray and neutron monitoring system. The -ray and neutron detection level which is planned to be adopted are "80 keV to 1.5 MeV (-ray)" and "0.025 eV to 15 MeV (neutron)". For the present shielding design, it is absolutely imperative for the safety review to validate the shielding ability which makes detection level lower than these -ray and neutron detector. For this purpose, the energy reduction of neutron and photon for water and concrete is evaluated by PHITS code. From the calculating results, it is found that the photon energy range extended to 10 MeV by water and concrete shielding material only, an additional shielding to decrease the photon energy of less than 1.5 MeV is indispensable.
Maebara, Sunao; Takahashi, Hiroki; Sakaki, Hironao; Hirabayashi, Keiichi*; Hidaka, Kosuke*; Shigyo, Nobuhiro*; Watanabe, Yukinobu*; Sagara, Kenshi*
JAEA-Conf 2011-002, p.199 - 204, 2011/09
