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Sano, Naruto; Yamashita, Naoki; Watanabe, Masaya; Tsukada, Manabu*; Hoshino, Kazutoyo*; Hirai, Koki; Ikegami, Yuta*; Tashiro, Shinsuke; Yoshida, Ryoichiro; Hatakeyama, Yuichi; et al.
JAEA-Technology 2023-029, 36 Pages, 2024/03
JAEA-Technology-2023-029.pdf:2.47MB
At the Waste Safety Testing Facility (WASTEF), the gamma ray irradiation device "Gamma Cell 220" was relocated from the 4th research building of the Nuclear Science Research Institute in FY2019, and the use of gamma ray irradiation has begun. Initially, Fuel Cycle Safety Research Group, Fuel Cycle Safety Research Division, Nuclear Safety Research Center, Sector of Nuclear Safety Research and Emergency Preparedness, the owner of this device, conducted the tests as the main user, but since 2022, other users, including those outside the organization, have started using it. The gamma ray irradiation device "Gamma Cell 220" is manufactured by Nordion International Inc. in Canada. Since it was purchased in 1989, the built-in 60Co radiation source has been updated once, and safety research related to nuclear fuel cycles, etc. It is still used for this purpose to this day. This report summarizes the equipment overview of the gamma ray irradiation device "Gamma Cell 220", its permits and licenses at WASTEF, usage status, maintenance and inspection, and future prospects.
Kitayama, Yoshiharu; Nogami, Mitsuhiro*; Hitomi, Keitaro*
Japanese Journal of Applied Physics, 63(3), p.032005_1 - 032005_6, 2024/03
Times Cited Count：0 Percentile：0.01(Physics, Applied)We introduce a novel gamma-ray imaging technique that uses detector response patterns. This method employs multiple shielding cubes randomly positioned in a three-dimensional configuration. Within the volume defined by these cubes, a unique gamma-ray flux pattern is formed based on the incidence direction of the gamma rays. This pattern can be measured using the responses of several scintillator cubes. By pre-measuring the detector response pattern and incidence direction of the gamma rays, the incidence direction can be estimated using an unfolding technique. Simulations were performed using a 
Cs point source. Our results show that a 10 MBq Cs source, located 3 m away from the imager, can be imaged with an angular resolution close to 10
. These findings suggest that our new method is comparable to existing gamma-ray imaging techniques. Potential applications of this imaging method include nuclear power plant decommissioning, nuclear medicine, security, and astronomy.
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.
Taira, Yoshitaka*; Endo, Shunsuke; Kawamura, Shiori*; Nambu, Taro*; Okuizumi, Mao*; Shizuma, Toshiyuki*; Omer, M.; Zen, H.*; Okano, Yasuaki*; Kitaguchi, Masaaki*
Physical Review A, 107(6), p.063503_1 - 063503_10, 2023/06
Times Cited Count：0 Percentile：0.01(Optics)no abstracts in English
NiBhattacharya, S.*; Tripathi, V.*; Rubino, E.*; Ajayi, S.*; Baby, L. T.*; Benetti, C.*; Lubna, R. S.*; Tabor, S. L.*; D
ring, J.*; Utsuno, Yutaka; et al.
Physical Review C, 107(5), p.054311_1 - 054311_17, 2023/05
Times Cited Count：1 Percentile：64.66(Physics, Nuclear)no abstracts in English
Yamamoto, Masahiko; Kono, Soma; Saegusa, Yu; Kuno, Takehiko; Sekine, Megumi; Inoue, Naoko; Noro, Naoko; Rodriguez, D.; Yamaguchi, Tomoki; Stinett, J.*
Proceedings of INMM & ESARDA Joint Annual Meeting 2023 (Internet), 10 Pages, 2023/05
The gamma-ray measurement part of the Non-Destructive Assay (NDA) course of safeguards and nuclear material accountancy was developed to focus on gamma-ray measurement allotting two days out of five days. The lectures on the basic characteristics and detection methods and mechanism of gamma-ray detectors were provided as e-learnings which were developed. The part for hands-on exercises were implemented in JAEA facility. Participants have set up each gamma-ray detector, and performed measurements of uranium and the other gamma-ray emitting nuclides. Also, uranium-235 enrichment measurements have been performed. In addition, the participants trained with a handheld gamma-ray spectrometer, HM-5, that is popular for IAEA safeguards as the preparation in the measurement exercise of fresh fuel assemblies in JRR-3, a research reactor facility of JAEA. This paper reports on the development, implementation, and feedback from participants on gamma-ray measurement part of the NDA course.
-ray analysisKinoshita, Norikazu*; Noto, Takuma*; Nakajima, Hitoshi*; Kosako, Kazuaki*; Kato, Takahiro*; Kuroiwa, Yoichi*; Kurabe, Misako*; Sasaki, Yuki*; Torii, Kazuyuki*; Maeda, Makoto; et al.
Journal of Radioanalytical and Nuclear Chemistry, 332(2), p.479 - 486, 2023/02
Times Cited Count：0 Percentile：0.01(Chemistry, Analytical)Kitayama, Yoshiharu; Nogami, Mitsuhiro*; Hitomi, Keitaro*
KEK Proceedings 2022-3, p.46 - 53, 2023/01
The position of a streetlight can be predicted from the direction and shape of one's shadow projected on the street at night by the light of the streetlight. The application of this idea to gamma-ray imagers is known as coded aperture. In this study, we proposed the Coded Cube Camera - POrtable (C3PO), which has a three-dimensional shielding and scintillator crystal arrangement, and is composed of lead, scintillator, and depletion cubes randomly arranged in a 3
33 Rurik's cube shape, with each. The output of each scintillator produces a three-dimensional shadow pattern, which is returned to the source direction distribution by unfolding. In this study, we investigated the characteristics and feasibility of the system by simulation using Geant 4.
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.
Yokoyama, Kaoru; Ohashi, Yusuke
Annals of Nuclear Energy, 175, p.109240_1 - 109240_7, 2022/09
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Decommissioning is planned at nuclear facilities that have been discontinued. We examined the evaluation method of uranium radioactivity for concrete waste generated by the decommissioning of nuclear facilities. Since the peaks of Ac-228, Tl-208, and K- 40 are derived from concrete waste, it is difficult to distinguish the 1001 keV peak emitted from the uranium source. We have derived a formula to correct gamma rays from concrete and the environment, and the amount of uranium was quantified. When the weight of concrete waste is about 300 kg, if the weight of uranium is 3 g or more, it can be quantified within a relative error of about 30%. Measurement tests were performed using homogeneous simulated concrete waste. Since uranium contamination is on the concrete surface at the uranium processing facility and small chunks generated by scraping the concrete surface will be stored in a drum and measured, it seems that the test of homogeneous concrete reflects the actual waste.
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.
Wada, Yuki*; Matsumoto, Takahiro*; Enoto, Teruaki*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Furuta, Yoshihiro*; Yonetoku, Daisuke*; Sawano, Tatsuya*; Okada, Go*; Nanto, Hidehito*; et al.
Physical Review Research (Internet), 3(4), p.043117_1 - 043117_31, 2021/12
Kitayama, Yoshiharu; Terasaka, Yuta; Sato, Yuki; Torii, Tatsuo
Journal of Nuclear Engineering and Radiation Science, 7(4), p.042006_1 - 042006_7, 2021/10
Hisadomi, Shohei*; Nakazawa, Kazuhiro*; Wada, Yuki*; Tsuji, Yuna*; Enoto, Teruaki*; Shinoda, Taro*; Morimoto, Takeshi*; Nakamura, Yoshitaka*; Yuasa, Takayuki*; Tsuchiya, Harufumi
Journal of Geophysical Research; Atmospheres, 126(18), p.e2021JD034543_1 - e2021JD034543_12, 2021/09
Times Cited Count：15 Percentile：79.1(Meteorology & Atmospheric Sciences)
CrKleis, H.*; Seidlitz, M.*; Blazhev, A.*; Kaya, L.*; Reiter, P.*; Arnswald, K.*; Dewald, A.*; Droste, M.*; Fransen, C.*; Mller, O.*; et al.
Physical Review C, 104(3), p.034310_1 - 034310_9, 2021/09
Times Cited Count：2 Percentile：33.7(Physics, Nuclear)no abstracts in English
Toh, Yosuke; Ozu, Akira; Tsuchiya, Harufumi; Furutaka, Kazuyoshi; Kitatani, Fumito; Komeda, Masao; Maeda, Makoto; Koizumi, Mitsuo
Proceedings of INMM & ESARDA Joint Virtual Annual Meeting (Internet), 8 Pages, 2021/08
Furutaka, Kazuyoshi; Ozu, Akira; Toh, Yosuke
Proceedings of INMM & ESARDA Joint Virtual Annual Meeting (Internet), 9 Pages, 2021/08
Pd and 
TcToh, Yosuke; Segawa, Mariko; Maeda, Makoto; Tsuneyama, Masayuki*; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Ebihara, Mitsuru*
Analytical Chemistry, 93(28), p.9771 - 9777, 2021/07
Times Cited Count：5 Percentile：39.78(Chemistry, Analytical)Amenomori, Michihiro*; Tsuchiya, Harufumi; Tibet AS
Collaboration*; 111 of others*
Physical Review Letters, 127(3), p.031102_1 - 031102_6, 2021/07
Times Cited Count：18 Percentile：86.79(Physics, Multidisciplinary)