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Fujiwara, Hidenori*; Nakatani, Yasuhiro*; Aratani, Hidekazu*; Kanai, Yuina*; Yamagami, Kohei*; Hamamoto, Satoru*; Kiss, Takayuki*; Yamasaki, Atsushi*; Higashiya, Atsushi*; Imada, Shin*; et al.
Physical Review B, 108(16), p.165121_1 - 165121_10, 2023/10
Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)Kondo, Yosuke*; Achouri, N. L.*; Al Falou, H.*; Atar, L.*; Aumann, T.*; Baba, Hidetada*; Boretzky, K.*; Caesar, C.*; Calvet, D.*; Chae, H.*; et al.
Nature, 620(7976), p.965 - 970, 2023/08
Times Cited Count:5 Percentile:92.64(Multidisciplinary Sciences)no abstracts in English
Wang, H.*; Yasuda, Masahiro*; Kondo, Yosuke*; Nakamura, Takashi*; Tostevin, J. A.*; Ogata, Kazuyuki*; Otsuka, Takaharu*; Poves, A.*; Shimizu, Noritaka*; Yoshida, Kazuki; et al.
Physics Letters B, 843, p.138038_1 - 138038_9, 2023/08
Times Cited Count:2 Percentile:68.16(Astronomy & Astrophysics)Detailed -ray spectroscopy of the exotic neon isotope Ne has been performed using the one-neutron removal reaction from Ne. Based on an analysis of parallel momentum distributions, a level scheme with spin-parity assignments has been constructed for Ne and the negative-parity states are identified for the first time. The measured partial cross sections and momentum distributions reveal a significant intruder p-wave strength providing evidence of the breakdown of the N = 20 and N = 28 shell gaps. Only a weak, possible f-wave strength was observed to bound final states. Large-scale shell-model calculations with different effective interactions do not reproduce the large p-wave and small f-wave strength observed experimentally, indicating an ongoing challenge for a complete theoretical description of the transition into the island of inversion along the Ne isotopic chain.
Umeda, Maki; Chudo, Hiroyuki; Imai, Masaki; Sato, Nana; Saito, Eiji
Review of Scientific Instruments, 94(6), p.063906_1 - 063906_8, 2023/06
Times Cited Count:0 Percentile:0(Instruments & Instrumentation)Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Fueda, Kazuki*; Takami, Ryu*; Minomo, Kenta*; Morooka, Kazuya*; Horie, Kenji*; Takehara, Mami*; Yamasaki, Shinya*; Saito, Takumi*; Shiotsu, Hiroyuki; Onuki, Toshihiko*; et al.
Journal of Hazardous Materials, 428, p.128214_1 - 128214_10, 2022/04
Times Cited Count:6 Percentile:68.71(Engineering, Environmental)Ando, Masaki; Saito, Kimiaki
JAEA-Technology 2021-032, 66 Pages, 2022/03
Since the occurrence of the accident at the TEPCO Fukushima Daiichi Nuclear Power Station, the Japan Atomic Energy Agency (JAEA) has been conducting a series of car-borne survey over a wide area in the eastern part of Japan using the monitoring system KURAMAII. In this report, outline of the car-borne surveys are summarized and the following characteristics of the temporal changes in each prefecture and region were investigated using the measured data obtained from 2012 to 2019; 1) Average and maximum values for each prefecture for the six years from 2014 to 2019, 2) Average values for each prefecture from 2012 to 2019, 3) Average values for each evacuation order area category, regional category, and northern Soso-area municipality in Fukushima Prefecture from 2012 to 2019, and 4) Average and maximum values for each municipality in each prefecture for four times (at almost two-year intervals) of the measurement results from 2012 to 2018.
Asano, Shun*; Ishii, Kenji*; Matsumura, Daiju; Tsuji, Takuya; Kudo, Kota*; Taniguchi, Takanori*; Saito, Shin*; Sunohara, Toshiki*; Kawamata, Takayuki*; Koike, Yoji*; et al.
Physical Review B, 104(21), p.214504_1 - 214504_7, 2021/12
Times Cited Count:0 Percentile:0(Materials Science, Multidisciplinary)Chudo, Hiroyuki; Imai, Masaki; Matsuo, Mamoru; Maekawa, Sadamichi; Saito, Eiji
Journal of the Physical Society of Japan, 90(8), p.081003_1 - 081003_11, 2021/08
Times Cited Count:3 Percentile:41.09(Physics, Multidisciplinary)Chen, Y.*; Sato, Masahiro*; Tang, Y.*; Shiomi, Yuki*; Oyanagi, Koichi*; Masuda, Takatsugu*; Nambu, Yusuke*; Fujita, Masaki*; Saito, Eiji
Nature Communications (Internet), 12, p.5199_1 - 5199_7, 2021/08
Times Cited Count:8 Percentile:61.37(Multidisciplinary Sciences)Ando, Masaki; Matsuda, Norihiro; Saito, Kimiaki
Nihon Genshiryoku Gakkai Wabun Rombunshi, 20(1), p.34 - 39, 2021/03
We measured count rates and air dose rates at 11 measurement points where the influence of the Fukushima Dai-ichi Nuclear Power Plant accident could be ignored to obtain parameters for a background equation applying to KURAMA-II loaded with the high sensitivity CsI(Tl) detector, C12137-01. It was found that the sensitivity of KURAMA-II (C12137-01) was about 10 times or more for background measurement, compared with KURAMA-II loaded with the standard type CsI(Tl) detector, C12137. A background equation for the energy range of 1400-2000 keV was determined as, y (Sv/h)=0.062 x (cps). We evaluated background air dose rates using KURAMA-II (C12137-01) for 71 municipalities and compared them with the previous study using KURAMA-II (C12137). Evaluated background air dose rates in this study were almost equal to those in the previous study. We confirmed that the background equation evaluated in this study was applicable for the KURAMA-II (C12137-01).
Yang, Z. H.*; Kubota, Yuki*; Corsi, A.*; Yoshida, Kazuki; Sun, X.-X.*; Li, J. G.*; Kimura, Masaaki*; Michel, N.*; Ogata, Kazuyuki*; Yuan, C. X.*; et al.
Physical Review Letters, 126(8), p.082501_1 - 082501_8, 2021/02
Times Cited Count:43 Percentile:96.7(Physics, Multidisciplinary)A quasifree (,) experiment was performed to study the structure of the Borromean nucleus B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for and orbitals, and a surprisingly small percentage of 9(2)% was determined for . Our finding of such a small component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in B. The present work gives the smallest - or -orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of or orbitals is not a prerequisite for the occurrence of a neutron halo.
Takeda, Yukiharu; Oya, Shinobu*; Pham, N. H.*; Kobayashi, Masaki*; Saito, Yuji; Yamagami, Hiroshi; Tanaka, Masaaki*; Fujimori, Atsushi*
Journal of Applied Physics, 128(21), p.213902_1 - 213902_11, 2020/12
Times Cited Count:8 Percentile:44.34(Physics, Applied)Ando, Masaki; Sasaki, Miyuki; Saito, Kimiaki
Journal of Nuclear Science and Technology, 57(12), p.1319 - 1330, 2020/12
Times Cited Count:4 Percentile:45.45(Nuclear Science & Technology)Air dose rates measured by car-borne surveys within 80 km range of Fukushima Dai-ichi Nuclear Power Plant using KURAMA systems from 2011 up to 2018 were analyzed, and decreasing trends and ecological half-life were evaluated. The decreasing speed of air dose rates became 0.08 over a period of seven years, indicating a much more rapid decrease than estimated by the physical decay of radiocesium (0.3). The fast components of the ecological half-lives evaluated in entire the evacuation order area were about 2 to 3 y, and were considerably larger than those outside the evacuation order area (0.4 to 0.5 y). To model the acceleration in the decrease of air dose rates observed in evacuation order areas, we modified the bi-exponential curve formula of ecological half-life and introduced the two-group model. The fast decreasing components of the ecological half-life evaluated using the two-group model after 2013 were 0.5 to 1 y, and were much shorter than those up to 2013, at 2 to 3 y.
Saito, Yuji; Fujiwara, Hidenori*; Yasui, Akira*; Kadono, Toshiharu*; Sugawara, Hitoshi*; Kikuchi, Daisuke*; Sato, Hideyuki*; Suga, Shigemasa*; Yamasaki, Atsushi*; Sekiyama, Akira*; et al.
Physical Review B, 102(16), p.165152_1 - 165152_8, 2020/10
Times Cited Count:1 Percentile:6.04(Materials Science, Multidisciplinary)Imai, Masaki; Chudo, Hiroyuki; Matsuo, Mamoru; Maekawa, Sadamichi; Saito, Eiji
Physical Review B, 102(1), p.014407_1 - 014407_5, 2020/07
Times Cited Count:6 Percentile:38.95(Materials Science, Multidisciplinary)Nambu, Yusuke*; Barker, J.*; Okino, Yuki*; Kikkawa, Takashi*; Shiomi, Yuki*; Enderle, M.*; Weber, T.*; Winn, B.*; Graves-Brook, M.*; Tranquada, J. M.*; et al.
Physical Review Letters, 125(2), p.027201_1 - 027201_6, 2020/07
Times Cited Count:45 Percentile:94.07(Physics, Multidisciplinary)Ito, Keita*; Yasutomi, Yoko*; Zhu, S.*; Nurmamat, M.*; Tahara, Masaki*; Toko, Kaoru*; Akiyama, Ryota*; Takeda, Yukiharu; Saito, Yuji; Oguchi, Tamio*; et al.
Physical Review B, 101(10), p.104401_1 - 104401_8, 2020/03
Times Cited Count:18 Percentile:73.04(Materials Science, Multidisciplinary)Sato, Tetsuro*; Ando, Masaki; Sato, Masako*; Saito, Kimiaki
Journal of Environmental Radioactivity, 210, p.105973_1 - 105973_7, 2019/12
Times Cited Count:9 Percentile:36.49(Environmental Sciences)A method was devised for estimation of external doses of Fukushima residents expected to return to their homes after evacuation orders are lifted. 211 residents expected to return to six towns and villages were surveyed in FY 2014, FY 2015, and FY2016. Interviewing returning residents about their expected life patterns after returning, air dose rate were measured along the reported personal trails representing their patterns of movement in daily life. Excluding 15 residents from whose homes we were unable to take air dose rate measurements, the maximum external effective dose and the average external effective dose were estimated respectively as 4.9 mSv/y and 0.86 mSv/y. Although the mean values and dispersion of external effective doses differ depending on the evacuation level, for 93.3% of all residents, the estimated external effective doses were less than 2 mSv/y. The average exposure dose at home accounts for 66.8% of the annual exposure dose.
Saito, Kimiaki; Mikami, Satoshi; Ando, Masaki; Matsuda, Norihiro; Kinase, Sakae; Tsuda, Shuichi; Yoshida, Tadayoshi; Sato, Tetsuro*; Seki, Akiyuki; Yamamoto, Hideaki*; et al.
Journal of Environmental Radioactivity, 210, p.105878_1 - 105878_12, 2019/12
Times Cited Count:33 Percentile:80.62(Environmental Sciences)