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Kimura, Yoshiki; Tsuchiya, Kenichi*
Radioisotopes, 72(2), p.121 - 139, 2023/07
Rapid and precise radioisotope identification in the scene of nuclear detection and nuclear security incidents is one of the challenging issues for the prompt response on the detection alarm or the incidents. A radioisotope identification algorithm using a deep artificial neural network model applicable to handheld gamma-ray detectors has been proposed in the present paper. The proposed algorithm automatically identifies gamma-emitting radioisotopes based on the count contribution ratio (CCR) from each of them estimated by the deep artificial neural network model trained by simulated gamma-ray spectra. The automated radioisotope identification algorithm can support first responders of nuclear detection and nuclear security incidents without sufficient experience and knowledge in radiation measurement. The authors tested the performance of the proposed algorithm using two different types of deep artificial neural network models in application to handheld detectors having high or low energy resolution. The proposed algorithm showed high performance in identifying artificial radioisotopes for actually measured gamma-ray spectra. It was also confirmed that the algorithm is applicable to identifying U and automated uranium categorization by analyzing estimated CCRs by the deep artificial neural network models. The authors also com-pared the performance of the proposed algorithm with a conventional radioisotope identification method and discussed promising ways to improve the performance of the algorithm using the deep artificial neural network.
Matsuda, Kenji*; Yasumoto, Toru*; Bendo, A.*; Tsuchiya, Taiki*; Lee, S.*; Nishimura, Katsuhiko*; Nunomura, Norio*; Marioara, C. D.*; Lervik, A.*; Holmestad, R.*; et al.
Materials Transactions, 60(8), p.1688 - 1696, 2019/08
Times Cited Count:16 Percentile:62.37(Materials Science, Multidisciplinary)no abstracts in English
Toda, Hiroyuki*; Yamaguchi, Masatake; Matsuda, Kenji*; Shimizu, Kazuyuki*; Hirayama, Kyosuke*; Su, H.*; Fujihara, Hiro*; Ebihara, Kenichi; Itakura, Mitsuhiro; Tsuru, Tomohito; et al.
Tetsu To Hagane, 105(2), p.240 - 253, 2019/02
Times Cited Count:0 Percentile:0(Metallurgy & Metallurgical Engineering)no abstracts in English
Tsuchiya, Katsuhiko; Kizu, Kaname; Murakami, Haruyuki; Yoshida, Kiyoshi; Kurihara, Kenichi; Hasegawa, Mitsuru*; Kuno, Kazuo*; Nomoto, Kazuhiro*; Horii, Hiroyuki*
IEEE Transactions on Applied Superconductivity, 22(3), p.4202304_1 - 4202304_4, 2012/06
Times Cited Count:8 Percentile:44.55(Engineering, Electrical & Electronic)no abstracts in English
Matsukawa, Makoto; Kikuchi, Mitsuru; Fujii, Tsuneyuki; Fujita, Takaaki; Hayashi, Takao; Higashijima, Satoru; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Ide, Shunsuke; Ishida, Shinichi; et al.
Fusion Engineering and Design, 83(7-9), p.795 - 803, 2008/12
Times Cited Count:17 Percentile:72.65(Nuclear Science & Technology)no abstracts in English
Ninomiya, Hiromasa; Akiba, Masato; Fujii, Tsuneyuki; Fujita, Takaaki; Fujiwara, Masami*; Hamamatsu, Kiyotaka; Hayashi, Nobuhiko; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Inoue, Nobuyuki; et al.
Journal of the Korean Physical Society, 49, p.S428 - S432, 2006/12
To contribute DEMO and ITER, the design to modify the present JT-60U into superconducting coil machine, named National Centralized Tokamak (NCT), is being progressed under nationwide collaborations in Japan. Mission, design and strategy of this NCT program is summarized.
Kikuchi, Mitsuru; Tamai, Hiroshi; Matsukawa, Makoto; Fujita, Takaaki; Takase, Yuichi*; Sakurai, Shinji; Kizu, Kaname; Tsuchiya, Katsuhiko; Kurita, Genichi; Morioka, Atsuhiko; et al.
Nuclear Fusion, 46(3), p.S29 - S38, 2006/03
Times Cited Count:13 Percentile:41.68(Physics, Fluids & Plasmas)The National Centralized Tokamak (NCT) facility program is a domestic research program for advanced tokamak research to succeed JT-60U incorporating Japanese university accomplishments. The mission of NCT is to establish high beta steady-state operation for DEMO and to contribute to ITER. The machine flexibility and mobility is pursued in aspect ratio and shape controllability, feedback control of resistive wall modes, wide current and pressure profile control capability for the demonstration of the high-b steady state.
Tsuchiya, Katsuhiko; Akiba, Masato; Azechi, Hiroshi*; Fujii, Tsuneyuki; Fujita, Takaaki; Fujiwara, Masami*; Hamamatsu, Kiyotaka; Hashizume, Hidetoshi*; Hayashi, Nobuhiko; Horiike, Hiroshi*; et al.
Fusion Engineering and Design, 81(8-14), p.1599 - 1605, 2006/02
Times Cited Count:1 Percentile:9.94(Nuclear Science & Technology)no abstracts in English
Tamai, Hiroshi; Akiba, Masato; Azechi, Hiroshi*; Fujita, Takaaki; Hamamatsu, Kiyotaka; Hashizume, Hidetoshi*; Hayashi, Nobuhiko; Horiike, Hiroshi*; Hosogane, Nobuyuki; Ichimura, Makoto*; et al.
Nuclear Fusion, 45(12), p.1676 - 1683, 2005/12
Times Cited Count:15 Percentile:45.44(Physics, Fluids & Plasmas)Design studies are shown on the National Centralized Tokamak facility. The machine design is carried out to investigate the capability for the flexibility in aspect ratio and shape controllability for the demonstration of the high-beta steady state operation with nation-wide collaboration, in parallel with ITER towards DEMO. Two designs are proposed and assessed with respect to the physics requirements such as confinement, stability, current drive, divertor, and energetic particle confinement. The operation range in the aspect ratio and the plasma shape is widely enhanced in consistent with the sufficient divertor pumping. Evaluations of the plasma performance towards the determination of machine design are presented.
Oikawa, Toshihiro; Tsuchiya, Katsuhiko; Kurihara, Kenichi; Kawamata, Yoichi; Fukuda, Takeshi*; Fujita, Takaaki; Neyatani, Yuzuru
Fusion Engineering and Design, 70(2), p.175 - 183, 2004/02
Times Cited Count:6 Percentile:40.63(Nuclear Science & Technology)The real-time feedback control of the plasma stored energy has been developed for control of the plasma MHD stability in the JT-60U tokamak. The plasma stored energy can be detected with high accuracy in real-time by the function parametrization method for various plasmas available in JT-60U, such as the ohmic plasma, the L-mode, the H-mode, the high poloidal beta mode and the reversed shear mode over a wide range of the plasma parameters. By manipulating the neutral beam injection power, the plasma stored energy has been successfully controlled along the preprogrammed reference waveform. Especially in the reversed shear mode, this feedback control scheme has improved the reproducibility of the formation of the internal transport barrier, and the MHD instability could be suppressed with keeping the normalized beta in the stable region. The D-T equivalent fusion amplification gain of 0.5 was sustained for 0.8 s in a reversed shear plasma by employing this feedback control scheme.
Oikawa, Toshihiro; Tsuchiya, Katsuhiko; Kurihara, Kenichi; Kawamata, Yoichi; Fukuda, Takeshi*; Fujita, Takaaki; Akasaka, Hiromi; Yonekawa, Izuru; Neyatani, Yuzuru
JAERI-Research 2003-027, 19 Pages, 2003/12
no abstracts in English
Seki, Masahiro; Hishinuma, Akimichi; Kurihara, Kenichi; Akiba, Masato; Abe, Tetsuya; Ishitsuka, Etsuo; Imai, Tsuyoshi; Enoeda, Mikio; Ohira, Shigeru; Okumura, Yoshikazu; et al.
Kaku Yugoro Kogaku Gairon; Mirai Enerugi Eno Chosen, 246 Pages, 2001/09
no abstracts in English
Ishihara, Yoshinao*; Matsuoka, Fushiki*; Sagawa, Hiroshi*; Kawahara, Kenichi*; Kataoka, Shinichi*; Shinohara, Yoshinori*; Muroi, Masayuki*; Tsuchiya, Makoto*; Tsujimoto, Keiichi*; Ohashi, Toyo*
JNC TJ8400 2001-011, 259 Pages, 2001/03
In this study, the basic design study on integrated computer system has been carried out in order to develop the integrated methodologies for future research and development activities of geological disposal system. The key conclusions are summarized as follows: (1) As the result of the investigation of work items and associated flow of information (data) between items in the second progress report by JNC, the interaction matrix and work flow chart have been identified in order to specify the basic configuration of the integrated computer system. In addition, the model chain and the structure of data relation between the repository design study and safety assessment study have been summarized. (2)We organized and examined the system factor and the information process flow in the design, safety analysis, and geological environment study based on the 2000 Report by JNC. Then we analyzed the workflow of geological disposal business when a specific site for a repository is fixed to obtain the system factor and the information process flow. We consider the fracture/porous media, site location (land/under the sea), and long-term stability of the crust (upheaval/sink) as the key factors in examining the workflow of geological disposal business. Then we organized the information change between the design and other study in geological disposal based on the 2000 Report by JNC. We examined the ideal workflow in which the design, safety analysis, and geologic environment study of geological disposal are closely coupled. We examined the scientific and technical base of the knowledge base (the system factor and the information process flow) which is derived from the above to construct the hierarchical structure of the knowledge base for geological disposal. (3)As the result of the interaction matrix and work flow chart for the R&D activities, the conceptual design and the function diagram on the integrated computer system has been proposed. (4)We examined the plan to ...
Iio, Shunji*; Oyama, Naoyuki; Tsuchiya, Katsuhiko; Oikawa, Toshihiro; Neyatani, Yuzuru; Kawamata, Yoichi; Kurihara, Kenichi
no journal, ,
no abstracts in English
Kimura, Yoshiki; Tsuchiya, Kenichi*
no journal, ,
A nuclear security event involving nuclear and other radioactive materials out of regulatory control (MORC) has potential severe consequence on public health, environments, economics and society. When a nuclear security event caused by MORC would be occurred, it is essential to identify the hazardous substances such as nuclear materials and radioisotopes as the initial response activity at the event scene. In this study, automated radioisotope identification algorism by Machine-Learning (ML) based gamma-ray spectrum analysis using handheld type detectors have been developed. The training data set for ML-based algorism has been developed based on detector simulation and the usability of the simulation-based data set for ML model training to perform radioisotope identification has been discussed.
Kimura, Yoshiki; Tsuchiya, Kenichi*; Okubo, Ayako*; Tanabe, Kosuke*; Kakuda, Hidetoshi*; Akiba, Norimitsu*; Tomikawa, Hirofumi
no journal, ,
Kimura, Yoshiki; Tsuchiya, Kenichi*
no journal, ,
no abstracts in English