Deformation and magicity in heavy actinides; First observation of the ground-state rotational band of Fm

Orlandi, R.; Asai, Masato; Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; Tsukada, Kazuaki; Sato, Tetsuya; Ito, Yuta; Suzaki, Fumi; Nagame, Yuichiro*; et al.

Physical Review Letters, 137(8), p.082501_1 - 082501_6, 2026/08

https://doi.org/10.1103/7gzt-ldn5

Development of an electron spin resonance spectroscopy code for measuring carbonate radicals in tooth enamel and verification of its practicality using irradiated Japanese macaque teeth

Yamashita, Takuma*; Hayashi, Teppei*; Mitsuyasu, Yusuke*; Ono, Kenta*; Iwami, Satone*; Kino, Yasushi*; Sekine, Tsutomu*; Oka, Toshitaka; Takahashi, Atsushi*; Shimizu, Yoshinaka*; et al.

International Journal of Radiation Biology, 102(7), p.880 - 887, 2026/07

https://doi.org/10.1080/09553002.2025.2510676

no abstracts in English

Laser stripping experiment of 400 MeV H beam in J-PARC

Harada, Hiroyuki; Saha, P. K.; Yoneda, Hitoki*; Michine, Yurina*; Onoda, Genki*; Yamada, Ippei; Shibata, Takanori*; Sato, Atsushi*; Kinsho, Michikazu

JPS Conference Proceedings (Internet), 45, p.011133_1 - 011133_8, 2026/06

https://doi.org/10.7566/JPSCP.45.011133

In high-intensity proton accelerators, negative hydrogen ions are charge-exchanged to protons by a carbon foil installed at the injection point of a ring accelerator. While this injection method can produce a high-intensity proton beam, it is a destructive method in which beams are passed through the foil, which leads to a short lifetime of the foil itself and to high radiation of the injection devices. Therefore, we proposed a non-destructive laser stripping injection scheme and develop for laser stripping experiment. In this study, a long-distance laser optical path of 70 m was newly constructed for the experiment. In this presentation, an overview of the laser stripping injection will be presented and the construction of the optical path, which is important for the execution of this experiment, will be reported. In addition, future experimental plans and prospects will be discussed.

Development of Linear Interpolation System for SMK Model parameters Evaluated from Cellular-scale simulation (LISMEC) and its application to BNCT dosimetry

Shigehira, Takafumi*; Watanabe, Tsubasa*; Suzuki, Minoru*; Hirata, Yuho; Ogawa, Tatsuhiko; Fujimura, Atsushi*; Sakurai, Yoshinori*; Sato, Tatsuhiko

Journal of Radiation Research (Internet), 67(2), p.170 - 181, 2026/03

https://doi.org/10.1093/jrr/rraf075

Development of the beam separation test device to evaluate the electric field of non-destructive electrostatic septum

Nagayama, Shota; Kinsho, Michikazu; Harada, Hiroyuki; Yamada, Ippei; Chimura, Motoki; Kojima, Kunihiro; Yamamoto, Kazami; Shimogawa, Tetsushi*; Sato, Atsushi*

Proceedings of 16th International Particle Accelerator Conference (IPAC25) (Internet), p.1025 - 1028, 2025/11

https://doi.org/10.18429/JACoW-IPAC2025-TUPB028

Slow extraction method of synchrotrons is used in nuclear and particle physics experiments, radiation therapy, and many other applications. In the slow extraction process, beam loss at the septum electrode, which separates the extracted beam from the circumferential side, induces activation and damage to the device. To solve this problem, we have devised an electric field measurement device named "Beam separation test device" to evaluate the two-dimensional electric field distribution of the nondestructive electrostatic septum that we are developing. The device consists of a prototype septum, horizontal and vertical wire scanners, and an electron gun installed on a movable stage fixed to a drive unit. This device measures the electric field by injecting an electron beam into the electric field and measuring the bending angle of the beam orbit. In developing this device, an additional optics system was designed to make a narrow electron beam to improve the measurement accuracy of the electric field distribution. In addition, we designed a beam dump that reduces secondary electron emission by utilizing energy loss when particles collide with materials. According to calculations of secondary electron emission, this beam dump can reduce secondary-emission into the chamber by up to 98%.

Nuclear hydrogen demonstration project using the HTTR; Demarcation of nuclear-industrial laws and design standards

Aoki, Takeshi; Shimizu, Atsushi; Ishii, Katsunori; Morita, Keisuke; Mizuta, Naoki; Kurahayashi, Kaoru; Yasuda, Takanori; Noguchi, Hiroki; Nomoto, Yasunobu; Iigaki, Kazuhiko; et al.

Annals of Nuclear Energy, 220, p.111503_1 - 111503_7, 2025/09

https://doi.org/10.1016/j.anucene.2025.111503

Aiming to establish coupling technologies between a high temperature gas cooled reactor and a hydrogen production plant, JAEA has initiated the HTTR Heat Application Test Project and is conducting the safety design and the safety analysis for the licensing of the HTTR Heat Application Test Facility. The present study proposed a relative evaluation methodology for the demarcation of applicable laws and design standards for the nuclear hydrogen production system and applied it to the HTTR Heat Application Test Facility. The evaluation results showed that a candidate applying the High Pressure Gas Safety Act to the Heat Application Test Facility (hydrogen production plant) and design standards established under the High Pressure Gas Safety Act to the steam reformer did not show the lowest category in any of the metrics, and was proposed as the most superior demarcation option for the HTTR Heat Application Test Facility.

Depositional age of the Lower-Middle Miocene Tanabe Group constrained by detrital zircon U-Pb ages and its implications for stress field

Abe, Noriaki; Hoshi, Hiroyuki*; Haji, Toshiki*; Sato, Katsushi*; Niki, Sota*; Hirata, Takafumi*; Iwano, Hideki*; Danhara, Toru*

Chishitsugaku Zasshi (Internet), 131(1), p.59 - 70, 2025/04

https://doi.org/10.5575/geosoc.2025.0003

To constrain the upper limit of the depositional age of the Tanabe Group, Early-Middle Miocene forearc basin deposit, this study obtained the detrital zircon U-Pb ages separated from eight sedimentary rock samples. We obtained 221 concordant ages from 330 zircon grains. The youngest grain age was 19.4 Ma, suggesting the upper limit of the depositional age is younger than 19.4 Ma, and no grain showed the depositional age indicated by foraminifera (16.3-15.1 Ma). Large-scale volcanic activities occurred in the Middle Miocene around Kii Peninsula, mainly after 15 Ma. The lack of grain younger than 15 Ma suggests that the Tanabe Group was deposited before 15 Ma. Sluggish volcanic activities in the provenance areas before 15 Ma may have caused the lack of zircons having ages close to the depositional period inferred from foraminifera.

Achievements and status of the STRAD project for radioactive liquid waste management

Arai, Yoichi; Watanabe, So; Nakahara, Masaumi; Funakoshi, Tomomasa; Hoshino, Takanori; Takahatake, Yoko; Sakamoto, Atsushi; Aihara, Haruka; Hasegawa, Kenta; Yoshida, Toshiki; et al.

Progress in Nuclear Science and Technology (Internet), 7, p.168 - 174, 2025/03

https://doi.org/10.15669/pnst.7.168

The Japan Atomic Energy Agency (JAEA) has been conducting a project named "Systematic Treatment of RAdioactive liquid waste for Decommissioning (STRAD)" project since 2018 for fundamental and practical studies for treating radioactive liquid wastes with complicated compositions. Fundamental studies have been conducted using genuine liquid wastes accumulated in a hot laboratory of the JAEA called the Chemical Processing Facility (CPF), and treatment procedures for all liquid wastes in CPF were successfully designed on the results obtained. As the next phase of the project, new fundamental and practical studies on primarily organic liquid wastes accumulated in different facilities of JAEA are in progress. This paper reviews the representative achievements of the STRAD project and introduces an overview of ongoing studies.

Improved multicomponent analysis method for electron spin resonance spectra of gamma-irradiated tooth enamel

Yamashita, Takuma*; Iwami, Satone*; Mitsuyasu, Yusuke*; Ono, Kenta*; Oka, Toshitaka; Takahashi, Atsushi*; Kino, Yasushi*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.

KEK Proceedings 2024-6, p.85 - 90, 2024/12

https://lib-extopc.kek.jp/preprints/PDF/2024/2425/2425006.pdf

To clarify the radiation effects of the accident at the TEPCO's Fukushima Daiichi NPP on living organisms, it is important to accurately estimate the dose to each individual. We have developed a multi-component analysis program using random number optimization to extract only the components derived from carbonate radicals from the ESR spectra.

Methodology development for explosion hazard evaluation in hydrogen production system using high temperature gas-cooled reactor

Morita, Keisuke; Aoki, Takeshi; Shimizu, Atsushi; Sato, Hiroyuki

Proceedings of 31st International Conference on Nuclear Engineering (ICONE31) (Internet), 6 Pages, 2024/11

https://doi.org/10.1115/ICONE31-135407