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Furuta, Takuya; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Tanimura, Yoshihiko
Nuclear Instruments and Methods in Physics Research A, 1086, p.171320_1 - 171320_8, 2026/06
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)A new function to incorporate nuclear data libraries with outgoing particles plus residual nuclei in specific excitation states for neutron-induced reactions has been implemented in a Monte Carlo simulation code, Particle and Heavy Ion Transport code System (PHITS). With this function, accurate predictions of outgoing particle spectra and angular distributions according to the nuclear data libraries become possible, while accounting for production of residual nuclei and de-excitation gammas, conserving total energy and momentum in each event. This feature allows users to perform high-precision simulations of detector responses and radiation damage in materials.
Fukui, Makoto; Chizuwa, Shingo*; Kikuchi, Norihiro; Tanaka, Masaaki; Hashimoto, Makoto
JAEA-Review 2025-045, 42 Pages, 2025/12
JAEA-Review-2025-045.pdf:2.95MB
Hot laboratory (HL) at Oarai Nuclear Engineering Institute is a facility that conducts post-irradiation testing of fuel samples and reactor materials in hot cells. A set of local sampling system (LSS) is installed as a radiation control equipment to monitor the concentration of radioactive materials in the air in work environment. The LSS of HL equipped 23 sampling points, which are called as local sampling ends (LSE). It was recognized that air sampling had not operated at some of the LSE, and the concentration of radioactive materials in the air was not measured as prescribed. In this report, we evaluated the effect of partial termination of the LSS and the resulting increase in sampling intervals on the control of radioactive material concentrations in the air using airflow analysis assuming the diffusion of radioactive materials from hot cells in the controlled area of HL. The Service Area of the HL, where 10 LSEs were set in a wide area, was selected as an evaluation area. Airflow analysis including the diffusion of virtual contaminant particles was conducted on the evaluation area. Diffusion of virtual contaminants from hot cells and sampling of virtual contaminants at LSEs are simulated in the case of LSS in fully working and LSS with termination of 4 LSEs. The evaluation results showed that the effect of the partial termination of LSS and the resulting increase in sampling intervals on the control of the concentration of radioactive materials in the air are small.
Cu and 
Cu with accelerator neutrons by deuterons and their separation from zincNagai, Yasuki*; Kawabata, Masako*; Saeki, Hideya*; Motoishi, Shoji*; Hashimoto, Kazuyuki; Tsukada, Kazuaki; Motomura, Arata*; Ota, Akio*; Takashima, Naoki*; Hashimoto, Shintaro; et al.
Frontiers in Nuclear Medicine (Internet), 5, p.1657125_1 - 1657125_11, 2025/10
In recent years, the radionuclide pair of Cu and Cu has attracted attention as an ideal theranostic agent. We proposed a novel production method utilizing a neutron source generated by deuteron beams at an accelerator facility. By irradiating enriched 
Zn samples with this neutron source, we measured the absolute activity and radionuclidic purity of the produced Cu. The results were consistent with calculations performed using PHITS and JENDL-5 developed by the Japan Atomic Energy Agency, confirming the reliability of the calculation method and demonstrating its capability to estimate the yields of trace radionuclides that are difficult to measure experimentally. Furthermore, we successfully separated Cu from the irradiated Zn sample using our developed sublimation and column separation techniques. These findings suggest that the production of Cu and Cu can be achieved in an economically sustainable manner at multiple sites.
Takahashi, Yoshio*; Miura, Hikaru*; Yamada, Shinya*; Sekizawa, Oki*; Nitta, Kiyofumi*; Hashimoto, Tadashi*; Yomogida, Takumi; Yamaguchi, Akiko; Okada, Shinji*; Itai, Takaaki*; et al.
Journal of Hazardous Materials, 495, p.139031_1 - 139031_19, 2025/09
Times Cited Count：1 Percentile：40.80(Engineering, Environmental)In this presentation, we analyzed the chemical state of cesium in radiocesium-bearing microparticles (CsMPs) released during the 2011 Fukushima Daiichi Nuclear Power Plant accident using high-resolution X-ray absorption spectroscopy (XANES) and micro X-ray fluorescence (
-XRF). The results identified two forms of cesium: one dissolved in glass and the other enriched on the surfaces of internal voids. The latter is considered to have originally existed as a gas and became concentrated during the cooling and solidification of the molten glass. These findings are crucial for understanding the formation process of CsMPs during the accident, as well as for future decommissioning and safety assessments.
Takami, Kazusa*; Gomi, Yuibi*; Yasuda, Ryuichi*; Abe, Shinichiro; Ito, Masatoshi*; Kanda, Hiroki*; Fukuda, Mitsuhiro*; Hashimoto, Masanori*
IEEE Transactions on Nuclear Science, 72(8), p.2622 - 2628, 2025/08
Times Cited Count：2 Percentile：80.51(Engineering, Electrical & Electronic)Neutron-induced soft errors in the terrestrial environment pose reliability issues for semiconductor devices. We have developed the new method for estimating terrestrial SER based on simulation coupled with one-time irradiation using a conventional neutron source. This method has been validated using 65-nm planar SRAMs. However, with the ongoing progression of process shrinkage and the increasing adoption of devices fabricated with newer processes, there is a growing demand for further experimental validation of the terrestrial SER estimation method for these advanced processes. In this work, we validated the estimation method for 12-nm 1-fin FinFETs and 28-nm planer SRAMs. The SERs estimated by our method were consistent with the SERs measured using a white neutron beam at RCNP within 28% error.
Gomi, Yuibi*; Takami, Kazusa*; Mizuno, Rurie*; Niikura, Megumi*; Yasuda, Ryuichi*; Deng, Y.*; Kawase, Shoichiro*; Watanabe, Yukinobu*; Abe, Shinichiro; Liao, W.*; et al.
IEEE Transactions on Nuclear Science, 72(8), p.2751 - 2762, 2025/08
Times Cited Count：1 Percentile：59.09(Engineering, Electrical & Electronic)The study of muon-induced soft errors in terrestrial settings remains underexplored even though the incidence of muon-induced soft errors tends to increas. In this study, we conducted positive and negative muon irradiation experiments on four types of 12-nm FinFET SRAMs. At the momentum where the SEU cross section peaks, 2-fin cells exhibit larger SEU cross sections than 1-fin cells for negative muons. Conversely, for positive muons, the SEU cross section is larger in 1-fin cells than in 2-fin cells due to the increased diffusion capacitance in 2-fin cells. We also performed the Monte Carlo simulations. The results suggest that a single sensitive volume with the same critical charge value cannot consistently reproduce the SEU cross sections for both types of muons.
Sakurai, Junya*; Torigata, Keisuke*; Matsunaga, Manabu*; Takanashi, Naoto*; Hibino, Shinya*; Kizu, Kenichi*; Morita, Akira*; Inomoto, Masahiro*; Shimohata, Nobuaki*; Toyota, Kodai; et al.
Tetsu To Hagane, 111(5), p.246 - 262, 2025/04
Times Cited Count：1 Percentile：40.12(Metallurgy & Metallurgical Engineering)Iwamoto, Yosuke; Matsuda, Hiroki*; Meigo, Shinichiro; Yonehara, Katsuya*; Pellemoine, F.*; Liu, Z.*; Lynch, K.*; Yoshida, Makoto*; Yabuuchi, Atsushi*; Yoshiie, Toshimasa*; et al.
Nuclear Instruments and Methods in Physics Research B, 557, p.165543_1 - 165543_8, 2024/12
Times Cited Count：1 Percentile：26.14(Instruments & Instrumentation)The number of displacements per atom is widely used as an indicator of irradiation damage to materials in proton accelerator facilities. Experiments have been carried out on protons below 3 GeV to verify the dpa of metallic materials. However, the dpa for high-energy protons above 3 GeV has not been measured. In order to validate the displacement cross sections of metals in the high-energy region, the electrical resistivity changes of aluminium, copper and tungsten wires at a temperature of 8 K were measured using protons with energy of 120 GeV. The results show that the conventional irradiation damage model of PHITS overestimates the experimental data. On the other hand, the calculation results using the athermal recombination correction model were in agreement with the experimental data.
Sato, Tatsuhiko; Hashimoto, Shintaro; M
rquez Damin, J. I.*; Niita, Koji*
Nuclear Instruments and Methods in Physics Research B, 557, p.165535_1 - 165535_8, 2024/12
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Ogawa, Tatsuhiko; Hirata, Yuho; Matsuya, Yusuke; Kai, Takeshi; Sato, Tatsuhiko; Iwamoto, Yosuke; Hashimoto, Shintaro; Furuta, Takuya; Abe, Shinichiro; Matsuda, Norihiro; et al.
EPJ Nuclear Sciences & Technologies (Internet), 10, p.13_1 - 13_8, 2024/11
The latest updates on PHITS, a versatile radiation transport code, focusing specifically on track-structure models are presented. Track structure calculations are methods used to simulate the movement of charged particles while explicitly considering each atomic reaction. Initially developed for radiation biology, these calculation methods aimed to analyze the radiation-induced damage to DNA and chromosomes. Several track-structure calculation models, including PHITS-ETS, PHITS-ETS for Si, PHITS-KURBUC, ETSART, and ITSART, have been developed and implemented to PHITS. These models allow users to study the behavior of various particles at the nano-scale across a wide range of materials. Furthermore, potential applications of track-structure calculations have also been proposed so far. This collection of track-structure calculation models, which encompasses diverse conditions, opens up new avenues for research in the field of radiation effects.
Iimoto, Takeshi*; Shimada, Kazumasa; Hashimoto, Makoto; Nagai, Haruyasu; Hohara, Shinya*; Murakami, Kenta*
Nihon Genshiryoku Gakkai-Shi ATOMO
, 66(7), p.356 - 360, 2024/07
no abstracts in English
Ishikawa, Akihisa; Koba, Yusuke*; Furuta, Takuya; Chang, W.*; Yonai, Shunsuke*; Matsumoto, Shinnosuke*; Hashimoto, Shintaro; Hirai, Yuta*; Sato, Tatsuhiko
Radiological Physics and Technology, 17(2), p.553 - 560, 2024/06
Deng, Y.*; Watanabe, Yukinobu*; Manabe, Seiya*; Liao, W.*; Hashimoto, Masanori*; Abe, Shinichiro; Tampo, Motonobu*; Miyake, Yasuhiro*
IEEE Transactions on Nuclear Science, 71(4, Part 2), p.912 - 920, 2024/04
Times Cited Count：1 Percentile：23.55(Engineering, Electrical & Electronic)With the miniaturization of semiconductors and the decrease in operating voltage, there is a growing interest and discussion in whether the muons in cosmic rays may be the source of single event upsets (SEUs). In the case of neutron-induced SEUs, it was reported that the irradiation side has the impact on SEU cross sections. Here, to investigate the impact of irradiation direction on muon-induced SEUs, we have measured and simulate muon-induced SEUs in 65-nm bulk SRAMs with different muon irradiation directions. It was found that the peak SEU cross section for the package side irradiation is about twice large as that for the board side irradiation. We also revealed that the difference in observed SEU cross sections between the package side and the board side irradiation is caused by differences in energy straggling due to changes in penetration depth depending on the incident direction.
Yomogida, Takumi; Hashimoto, Tadashi; Okumura, Takuma*; Yamada, Shinya*; Tatsuno, Hideyuki*; Noda, Hirofumi*; Hayakawa, Ryota*; Okada, Shinji*; Takatori, Sayuri*; Isobe, Tadaaki*; et al.
Analyst, 149(10), p.2932 - 2941, 2024/03
Times Cited Count：2 Percentile：23.63(Chemistry, Analytical)In this study, we successfully applied a transition-edge sensor (TES) spectrometer as a detector for microbeam X-ray measurements from a synchrotron X-ray light source to determine uranium (U) distribution at the micro-scale and its chemical species in biotite obtained from the U mine. It is difficult to separate the fluorescent X-ray of the U L
line at 13.615 keV from that of the Rb K line at 13.395 keV in the X-ray fluorescence spectrum with an energy resolution of approximately 220 eV of the conventional silicon drift detector (SDD). Meanwhile, the fluorescent X-rays of U L and Rb K were fully separated by TES with 50 eV energy resolution at the energy of around 13 keV. The successful peak separation by TES led to an accurate mapping analysis of trace U in micro-X-ray fluorescence measurements and a decrease in the signal-to-background ratio in micro-X-ray absorption near edge structure spectroscopy.
Sato, Tatsuhiko; Iwamoto, Yosuke; Hashimoto, Shintaro; Ogawa, Tatsuhiko; Furuta, Takuya; Abe, Shinichiro; Kai, Takeshi; Matsuya, Yusuke; Matsuda, Norihiro; Hirata, Yuho; et al.
Journal of Nuclear Science and Technology, 61(1), p.127 - 135, 2024/01
Times Cited Count：284 Percentile：99.98(Nuclear Science & Technology)The Particle and Heavy Ion Transport code System (PHITS) is a general-purpose Monte Carlo radiation transport code that can simulate the behavior of most particle species with energies up to 1 TeV (per nucleon for ions). Its new version, PHITS3.31, was recently developed and released to the public. In the new version, the compatibility with high-energy nuclear data libraries and the algorithm of the track-structure modes have been improved. In this paper, we summarize the upgraded features of PHITS3.31 with respect to the physics models, utility functions, and application software introduced since the release of PHITS3.02 in 2017.
Ogawa, Tatsuhiko; Hashimoto, Shintaro; Sato, Tatsuhiko
Journal of Nuclear Science and Technology, 61(1), p.68 - 73, 2024/01
Times Cited Count：4 Percentile：53.94(Nuclear Science & Technology)The gamma de-excitation model of the general-purpose radiation transport code Particle and Heavy Ion Transport code System (PHITS), called the Evaluated Nuclear Structure Data File (ENSDF-)-Based Isomeric Transition and isomEr production Model (EBITEM) has been upgraded with focus on precise neutron capture reaction simulation. The first de-excitation subsequent to neutron capture of numerous nuclei, which was formerly simulated by a model based on the single particle model, is calculated using the Evaluated Gamma Activation File (EGAF). The database used for further de-excitation, ENSDF, retrieved in 2013, was replaced with Reference Input Parameter Library 3 (RIPL-3) to consider internal conversion. The internal conversion process was interfaced with the atomic de-excitation model to assess the emission of Auger electrons and fluorescent X-rays. The spectra of gamma-rays from neutron capture reactions calculated by the upgraded EBITEM correlate better with the evaluated cross section data than those of the previous version.
Kuga, Naoya*; Shiiba, Takuro*; Sato, Tatsuhiko; Hashimoto, Shintaro; Kuroiwa, Yasuyoshi*
Journal of Nuclear Science and Technology, 61(1), p.136 - 145, 2024/01
Times Cited Count：5 Percentile：63.07(Nuclear Science & Technology)This study aims to verify the accuracy of PHITS in terms of photon and electron transport and provide essential data for its application in clinical dosimetry in high-energy photon beam therapy. Percentage depth dose (PDD), beam profiles, and output factor (OPF) in a water phantom with various field sizes created by a Clinac 21EX linear accelerator were measured using an ionization chamber. Experimental setups were precisely reproduced by PHITS version 3.24, and the percentage differences (%Diff) between the measured and calculated data were evaluated. The average %Diff of PDDs obtained from PHITS and measurement were within 10% and 2% in the build-up and fall-off regions, respectively. For beam profiles, the average %Diff in the plateau region was within 3%; the differences between the calculated and measured distances from the central axis to 50% dose level were within 2 mm. These differences were lower than their tolerance levels. The consistency between the PHITS and EGSnrc was better; their %Diff was within 1% in most cases. The concurrence between the PHITS and measurement shown in this study demonstrates the potential clinical application of PHITS in high-energy photon beam therapy, given its similar dose calculation accuracy compared with EGSnrc.
Mo for production of medical 
Tc by Mo(
)TcHashimoto, Shintaro; Nagai, Yasuki*
Journal of the Physical Society of Japan, 92(12), p.124202_1 - 124202_11, 2023/12
Times Cited Count：2 Percentile：28.18(Physics, Multidisciplinary)Tc, which is a daughter nuclide of 
Mo, is used worldwide for medical imaging. However, there is a problem with the supply of Tc (Mo) due to the replacement of aging reactors. A method to produce Tc by irradiating Mo with protons using medical cyclotrons has been proposed. In this study, we presented a method to determine individual excitation functions for Mo(
)Tc using measured excitation functions for 
Mo()Tc. The method was validated by comparing estimated radionuclide purities of Tc in enriched Mo samples using the determined excitation functions with measured ones. In this study, we found that the content of 
Mo, 
Mo, and 
Mo should be low in order to produce Tc with high radionuclide purity. The results of this study play an important role in discussion of the required Mo compositions in enriched Mo, taking into account the constraints of each facility.
Abe, Shinichiro; Hashimoto, Masanori*; Liao, W.*; Kato, Takashi*; Asai, Hiroaki*; Shimbo, Kenichi*; Matsuyama, Hideya*; Sato, Tatsuhiko; Kobayashi, Kazutoshi*; Watanabe, Yukinobu*
IEEE Transactions on Nuclear Science, 70(8, Part 1), p.1652 - 1657, 2023/08
Times Cited Count：7 Percentile：76.13(Engineering, Electrical & Electronic)Single event upsets (SEUs) caused by neutrons is a reliability problem for microelectronic devices in the terrestrial environment. Acceleration tests using white neutron beam provide realistic soft error rates (SERs), but only a few facilities can provide white neutron beam in the world. If single-source irradiation applicable to diverse neutron source can be utilized for the evaluation of the SER in the terrestrial environment, it contributes to solve the shortage of beam time. In this study, we investigated the feasibility of the SER estimation in the terrestrial environment by any one of these measured data with the SEU cross sections obtained by PHITS simulation. It was found that the SERs estimated by our proposed method are within a factor of 2.7 of that estimated by the Weibull function. We also investigated the effect of simplification which reduce the computational cost in simulation to the SER estimation.
probed by anisotropic low-energy excitationsIshihara, Kota*; Roppongi, Masaki*; Kobayashi, Masayuki*; Imamura, Kumpei*; Mizukami, Yuta*; Sakai, Hironori; Opletal, P.; Tokiwa, Yoshifumi; Haga, Yoshinori; Hashimoto, Kenichiro*; et al.
Nature Communications (Internet), 14, p.2966_1 - 2966_7, 2023/05
Times Cited Count：53 Percentile：98.05(Multidisciplinary Sciences)The superconducting symmetry of the heavy fermion uranium-based superconductor UTe is investigated using low temperature penetration depth measurements. The anisotropic low-energy quasiparticle excitations indicates multiple superconducting components in a chiral complex form. The most consistent is a chiral non-unitary state.
