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CsKobayashi, Hikaru*; Ma, X.*; Suto, Masahito*; Yamamori, Ryo*; Furuta, Takuya
Radiation Measurements, 197, p.107743_1 - 107743_13, 2026/09
Monte Carlo photon transport simulations are widely used to predict indoor dose distributions from Cs-137 ground deposition, but their computational cost can be high. To improve efficiency, we propose the fluence boundary method (FBM), which accounts for contributions from distant sources by applying analyzed photon fluence profiles at near-site boundaries surrounding a building. These profiles are defined according to the land-cover type adjacent to each boundary. The method was validated by comparing FBM results with full simulations, demonstrating that FBM achieved a maximum absolute percentage error below 5% across indoor dose distributions. The feasibility of representing fluence boundaries using land-cover types was further examined by evaluating the impact of uncertainties in relaxation mass depth (
) for paved and soil surfaces. The normalized indoor dose distributions showed weak dependence on within a reasonable range, indicating that indoor dose distributions can be reliably predicted using representative values when doses are normalized to measurements.
Shimomura, Koichiro*; Koda, Akihiro*; Pant, A. D.*; Sunagawa, Hikaru*; Fujimori, Hiroshi*; Umegaki, Izumi*; Nakamura, Jumpei*; Fujihara, Masayoshi; Tampo, Motonobu*; Kawamura, Naritoshi*; et al.
Interactions (Internet), 245(1), p.31_1 - 31_6, 2024/12
Times Cited Count：3 Percentile：91.16(Physics, Atomic, Molecular & Chemical)Kobayashi, Hikaru*; Suto, Masahito*; Otsuki, Kentaro*; Yoshimura, Kazuya; Yoshida, Hiroko*
Japan Architectural Review (Internet), 6(1), p.e12353_1 - e12353_12, 2023/00
Otosaka, Shigeyoshi; Amano, Hikaru; Ito, Toshimichi; Kawamura, Hideyuki; Kobayashi, Takuya; Suzuki, Takashi; Togawa, Orihiko; Chaykovskaya, E. L.*; Lishavskaya, T. S.*; Novichkov, V. P.*; et al.
Journal of Environmental Radioactivity, 91(3), p.128 - 145, 2006/00
Times Cited Count：21 Percentile：41.60(Environmental Sciences)Distributions of radionuclides (
Sr, Cs and 
Pu) in seabed sediment in the Japan Sea were observed during 1998-2002. Observed inventories of anthropogenic radionuclides in sediment ranged 0.1-86 Bq m
for Sr, 23-379 Bq m for Cs and 0.1-86 Bq m for Pu. In the deep part (
2 km depth) of the western Japan Basin, Pu/Cs inventory ratios were larger than those in the central Yamato Basin although inventories of radionuclides were not different between basins. The higher Pu/Cs ratios in the western Japan Basin were derived by the production of Pu-enriched particle in the surface layer and effective sinking of particulate materials in this region. In the marginal Yamato Basin and the Ulleung Basin, both inventories and Pu/Cs ratios in sediment were larger than those in the central Yamato Basin. In the eastern/southern Japan Sea, it was suggested that the supply of particulate radionuclides by the TWC enhanced accumulation of radionuclides in this region.
Ito, Toshimichi; Aramaki, Takafumi*; Otosaka, Shigeyoshi; Suzuki, Takashi; Togawa, Orihiko; Kobayashi, Takuya; Kawamura, Hideyuki; Amano, Hikaru; Senju, Tomoharu*; Chaykovskaya, E. L.*; et al.
Journal of Nuclear Science and Technology, 42(1), p.90 - 100, 2005/01
Times Cited Count：14 Percentile：65.75(Nuclear Science & Technology)During 1996-2002, a wide-area research project on anthropogenic radionuclides was done in the Japanese and Russian EEZ of the Japan Sea to investigate their migration. As the results of expeditions in 2001 and 2002, (1) the concentrations and distributions of radionuclides are similar to the results of previous, (2) inventories of these radionuclides indicate accumulation in the Japan Sea seawater compared to the amounts supplied by global fallout, (3) Sr and Cs concentrations in intermediate layer show temporal variations, and 4) the variations may reflect the water mass movement in upper part of the Japan Sea.
Fe
NxKasatani, Hirofumi*; Omura, Masashi*; Yokoyama, Katsumi*; Kobayashi, Kurima*; Nishihata, Yasuo; Yagi, Kenichiro*; Terauchi, Hikaru*
Japanese Journal of Applied Physics, 38(Suppl.38-1), p.433 - 435, 1999/06
Times Cited Count：3 Percentile：18.45(Physics, Applied)High energy XAFS studies of Sm: K-edge in Sm2Fe17Nx with x = 0.0, <= 0.1, 0.5, 2.0 and 3.0 were carried out at room temperature in order to clarify the relation between the local structure around the Sm-atom and the change of the magnetic property due to the absorption of nitrogen atom. In the XANES region, we firstly found the change of Sm electron state by nitriding because of the change of the shape in the absorption edge junp. In the result of the EXAFS spectra, we confirmed that the Sm-Fe distance was expanded monotonously due to the absorption of N-atom.
Pb and 
Be within the Kuji River watershed, JapanMatsunaga, Takeshi; Amano, Hikaru; Ueno, Takashi; Yanase, Nobuyuki; Kobayashi, Yoshii
Journal of Environmental Radioactivity, 26, p.3 - 17, 1995/00
Times Cited Count：16 Percentile：47.76(Environmental Sciences)no abstracts in English
CsUeno, Takashi; Amano, Hikaru; Kobayashi, Yoshii
Hoken Butsuri, 29(1), p.17 - 22, 1994/03
no abstracts in English
Amano, Hikaru; Kobayashi, Yoshii; ;
Kankyo Radon, p.42 - 52, 1992/03
no abstracts in English
Amano, Hikaru; Matsunaga, Takeshi; Ueno, Takashi; Yanase, Nobuyuki; Kobayashi, Yoshii
3rd Int. Symp. on Advanced Nuclear Energy Research; Global Environment and Nuclear Energy, 4 Pages, 1991/00
no abstracts in English
Kobayashi, Kensei*; Kawamoto, Yukinori*; Sarker, P. K.*; Ono, Keisuke*; Kuwahara, Hideharu*; Obayashi, Yumiko*; Kaneko, Takeo*; Mita, Hajime*; Yabuta, Hikaru*; Yoshida, Satoshi*; et al.
no journal, ,
Yokobori, Shinichi*; Kawaguchi, Yuko*; Shimizu, Yasuyuki*; Kawashiri, Narutoshi*; Shiraishi, Keisuke*; Sugino, Tomohiro*; Takahashi, Yuta*; Yang, Y.*; Tanigawa, Yoshiaki*; Hashimoto, Hirofumi*; et al.
no journal, ,
no abstracts in English
Yokobori, Shinichi*; Kawaguchi, Yuko*; Yang, Y.*; Kawashiri, Narutoshi*; Shiraishi, Keisuke*; Shimizu, Yasuyuki*; Takahashi, Yuta*; Sugino, Tomohiro*; Narumi, Issei; Sato, Katsuya; et al.
no journal, ,
no abstracts in English
Yokobori, Shinichi*; Kawaguchi, Yuko*; Yang, Y.*; Kawashiri, Narutoshi*; Shiraishi, Keisuke*; Shimizu, Yasuyuki*; Takahashi, Yuta*; Sugino, Tomohiro*; Narumi, Issei; Sato, Katsuya; et al.
no journal, ,
no abstracts in English
Yokobori, Shinichi*; Kobayashi, Kensei*; Mita, Hajime*; Yabuta, Hikaru*; Nakagawa, Kazumichi*; Narumi, Issei; Hayashi, Nobuhiro*; Tomita, Kaori*; Kawaguchi, Yuko*; Shimizu, Yasuyuki*; et al.
no journal, ,
no abstracts in English
-ray directional radiation dose detector with good efficiency for field surveyYamamori, Ryo*; Kobayashi, Hikaru*; Honta, Shohei*; Yoshino, Hiroshi*; Nozaki, Atsuo*; Ichijo, Yusuke*; Hijikata, Yoshio*; Yoshida, Hiroko*; Furuta, Takuya
no journal, ,
Understanding radiation field is important to predict radiation dose rate in newly constructing buildings in an area widely contaminated by radioactive nuclei. Directional spectra of the radiations are important to consider the shielding effect of the building. We adopts a method to measure the directional spectra by adopting a plate of lead collimator in front of the scintillator and subtract the values from the spectra measured without lead collimator. We investigated a possible weight saving detection system having sufficient detection efficiency. The investigation was carried out for the condition of the collimator radius (
= 10, 15, 20 cm) and the distance between collimator and detector (
= 1, 3, 5 cm). We found that three combinations satisfied the 90
field view and the detection efficiency became better with larger collimator radius. On the other hand, larger collimator radius indicate heavier detection system. Therefore, we developed an optimum detection system for field survey with the 15 cm diameter plate (10kg), the scintillator (3.4kg), and the folder (1.0kg).
Tone, Masaya; Shiramizu, Daiki; Katsuoka, Nanako; Aoyama, Yusuke; Miyata, Koshi; Fukuda, Shigeki; Otaka, Hikaru; Kobayashi, Hidekazu; Kodaka, Akira
no journal, ,
The replacement of existing 2nd glass melter with the 3rd glass melter is scheduled from 2025 to 2026 in Tokai Vitrification Facility, TVF. The bottom shape of 3rd melter was changed from the square pyramid of 2nd melter to a cone to improve ability to discharge platinum group elements. Therefore, it is necessary to confirm operational parameters appropriate for the 3rd melter with cone shaped bottom. Operational test using non-radioactive simulant of liquid waste was carried out to ensure the appropriate operational parameters that accommodate key control values such as glass temperature.
Yokobori, Shinichi*; Yang, Y.*; Sugino, Tomohiro*; Kawaguchi, Yuko*; Itahashi, Shiho*; Fujisaki, Kenta*; Fushimi, Hidehiko*; Hasegawa, Sunao*; Hashimoto, Hirofumi*; Hayashi, Nobuhiro*; et al.
no journal, ,
Kobayashi, Kensei*; Mita, Hajime*; Nakashima, Satoru*; Yabuta, Hikaru*; Yokobori, Shinichi*; Narumi, Issei; Naganuma, Takeshi*
no journal, ,
no abstracts in English
Yokobori, Shinichi*; Yang, Y.*; Kawaguchi, Yuko*; Sugino, Tomohiro*; Takahashi, Yuta*; Narumi, Issei; Takahashi, Yuichi*; Hayashi, Nobuhiro*; Yoshimura, Yoshitaka*; Tabata, Makoto*; et al.
no journal, ,
no abstracts in English
