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Amenomori, Michihiro*; Tsuchiya, Harufumi; Tibet AS
Collaboration*; 116 of others*
Astrophysical Journal, 954(2), p.200_1 - 200_7, 2023/09
Times Cited Count：1 Percentile：44.78(Astronomy & Astrophysics)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.
Kitayama, Yoshiharu
Gamma Ray Imaging; Technology and Applications, p.165 - 179, 2023/00
A gamma-ray imager is a powerful tool for visualizing the distribution of radioactive materials. Recently, it has been applied to the decommissioning site of the Fukushima Daiichi Nuclear Power Station. At the decommissioning site, an imager compact, lightweight, and capable of quantitative evaluation of radioactivity is demanded. The Gamma-ray Imager using Small-Angle Scattering (GISAS) was proposed as a gamma-ray imager that meets all these requirements. GISAS consists of several shield-free directional gamma-ray detectors that detect only small-angle Compton scattering. Simulations and experiments verified the feasibility of the shield-free directional gamma-ray detectors. The shield-free directional gamma-ray detector consists of a scatterer that detects small-angle Compton scattering and an absorber that detects the scattered gamma rays. By setting an appropriate energy window for each detector, only scattering events that can be considered almost straightforward are detected. Through simulations and experiments, we have confirmed that using a silicon drift detector as the scatterer and a Gd3Al2Ga3O12 scintillator as the absorber, we can detect only small-angle Compton scattering events and obtain directionality for 662 keV gamma rays.
Shibata, Hiroshi; Takeuchi, Tomoaki; Seki, Misaki; Shibata, Akira; Nakamura, Jinichi; Ide, Hiroshi
JAEA-Data/Code 2021-018, 42 Pages, 2022/03
JAEA-Data-Code-2021-018.pdf:2.78MB
JAEA-Data-Code-2021-018-appendix(CD-ROM).zip:0.15MB
Japan Materials Testing Reactor (JMTR) in Oarai Research and Development Institute of the Japan Atomic Energy Agency has been developing various reactor materials, irradiation techniques and instruments for more than 30 years. Among them, the development of self-powered neutron detectors (SPNDs) and gamma detectors (SPGDs) has been carried out, and several research results have been reported. However, most of the results are based on the design study of the detector development and the results of in-core irradiation tests and gamma irradiation tests using Cobalt-60. In this report, a numerical code is developed based on the paper "Neutron and Gamma-Ray Effects on Self-Powered In-Core Radiation Detectors" written by H.D. Warren and N.H. Shah in 1974, in order to theoretically evaluate the self-powered radiation detectors.
Kitayama, Yoshiharu; Terasaka, Yuta; Sato, Yuki; Torii, Tatsuo
Journal of Nuclear Engineering and Radiation Science, 7(4), p.042006_1 - 042006_7, 2021/10
Wada, Yuki*; Enoto, Teruaki*; Nakazawa, Kazuhiro*; Odaka, Hirokazu*; Furuta, Yoshihiro; Tsuchiya, Harufumi
Journal of Geophysical Research; Atmospheres, 125(20), p.e2020JD033193_1 - e2020JD033193_17, 2020/10
Times Cited Count：3 Percentile：15.1(Meteorology & Atmospheric Sciences)Enoto, Teruaki*; Wada, Yuki*; Furuta, Yoshihiro*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Okuda, Kazufumi*; Makishima, Kazuo*; Sato, Mitsuteru*; Sato, Yosuke*; Nakano, Toshio*; et al.
Nature, 551(7681), p.481 - 484, 2017/11
Times Cited Count：118 Percentile：97.59(Multidisciplinary Sciences)Takeuchi, Tomoaki; Otsuka, Noriaki; Shibata, Hiroshi; Nagata, Hiroshi; Endo, Yasuichi; Matsui, Yoshinori; Tsuchiya, Kunihiko
KAERI/GP-418/2015, p.110 - 112, 2015/00
irradiation experiments with a 
Co source were carried out for developing Self-Powered Gamma Detectors (SPGDs) with lead (Pb) emitter and Self-Powered Neutron Detectors (SPNDs) with Pt-40%Rh emitter prior to in-core irradiation experiments. The results showed the output currents of the SPGDs were proportional to the dose rate in the range from about 200-6000 Gy/h with about 10% accuracy. In the case of SPNDs, the output currents flowed in inverse direction and were an order of magnitude lower compared with that of the SPGDs. These different behaviors of the output currents are considered to be caused by the difference in the emitter sizes and the current component originated at the MI cables.
*
JNC TJ9400 2000-008, 61 Pages, 2000/02
For studies on nuclear transmutation of long-lived fission products (LLFPs) in a fast reactor, detailed characteristics of reactor core such as transmutation performance have to be investigated, so accurate neutron cross section data of LLFPs become necessary. Therefore, the keV-neutron capture cross sections of Tc-99, which is one of important LLFPs, were measured in the present study to obtain the accurate data. The measurement was relative to the standard capture cross sections of Au-197. A neutron time-of-flight method was adopted with a ns-pulsed neutron source by a Pelletron accelerator and a large anti-Compton NaI(TI) gamma-ray detector. As a result, the capture cross sections of Tc-99 were obtained with the error of about 5 % in the incident neutlon energy region of 10 to 600 keV. The present data were compared with other experimental data and the evaluated values of JENDL-3.2, and it was found that the evaluations of JENDL-3.2 were 15-20 % smaller than the present measurements.
M.Hoek*; Nishitani, Takeo; Ikeda, Yujiro; Morioka, Atsuhiko
JAERI-M 94-002, 25 Pages, 1994/01
no abstracts in English
Emoto, Takehiko; ; Ando, Hideki
PNC TN9410 93-186, 65 Pages, 1993/09
From the viewpoint of radiation protection and radiation shielding evaluation, the needs to know the positions that are irradiated by radiation are increasing, because measuring irradiated positions is useful for detecting local streaming at working areas in nuclear facilities and evaluating beam-loss from accelerators. We have investigated and experimented the characteristics of plastic scintillating fiber(PSF), that has been recently developed one of most popular position sensitive particle detectors in high energy physics, for purpose of that we can apply them to the radiation measurements as a position sensitive radiation detector. First, we referred to the results of the committed research performed in last year and to relative works. And, to aim for improvement of efficiency of gamma-ray and for stretch of the detector, we investigated efficiency and resolution of the detectors giving priorities to (a) variation of length and bundle of PSFs hamess, and (b) variation of the irradiated positions. As the results of referring to the works and the experiments on the detectors, we got the followings, (1)The method using the difference of reaching time between the scintillation photons from both ends of PSF is hopeful as position sensitive radiation detecting, because PSF has good time resolution and the time measurements have been recently developed to be rather easy and accurate methods. (2)Position resolution is 20cm to 30cm for collimated gamma-ray of 
Cs. And, the detectors bundled of ten PSFs have better characteristics of both efficiency and resolution. (3)When the detector is irradiated at near one of the ends, the efficiency and resolution will be 10% to 30% worse than irradiated at middle of it.
; ; Makino, Akihiro; Murano, Toru*; Wakabayashi, Hiroaki*; Yoshii, Koji*
PNC TN841 77-06, 76 Pages, 1976/03
no abstracts in English
Ito, Chikara
no journal, ,
no abstracts in English
