Study of dissolved radon and optimization of Rn/At generator

Tanaka, Ko*; Shimizu, Yusuke*; Ida, Tomonori*; Washiyama, Koshin*; Nishinaka, Ichiro*; Asai, Masato; Segawa, Mariko; Yokoyama, Akihiko*

Radiochimica Acta, 114(3), p.221 - 229, 2026/04

https://doi.org/10.1515/ract-2025-0082

We are developing a Rn/At generator system to produce and deliver the medical radioisotope At. This study analyzed the dissolution of Rn in solution to investigate gas-phase recovery conditions of Rn in the Rn/At generator system. The dissolution of a Bi target in a nitric-hydrochloric acid mixture and subsequent neutralization has been shown to enhance the Rn recovery efficiency. The gas-phase Rn recovery rate reached 88%, while 50% of available At has been recovered, and further improvement can be expected in the future.

Development of neutron self-indication thermometry at J-PARC

Segawa, Mariko; Toh, Yosuke; Maeda, Makoto; Kai, Tetsuya

Journal of Nuclear Science and Technology, 62(3), p.268 - 277, 2025/03

https://doi.org/10.1080/00223131.2024.2424519

Neutron capture cross section measurement of I and I using the NaI(Tl) spectrometer of the ANNRI beamline at J-PARC

Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Toh, Yosuke; Segawa, Mariko; Maeda, Makoto; Katabuchi, Tatsuya*

European Physical Journal A, 60(5), p.120_1 - 120_14, 2024/05

https://doi.org/10.1140/epja/s10050-024-01333-3

Neutron capture cross section measurement of I and I using ANNRI at MLF/J-PARC

Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Toh, Yosuke; Segawa, Mariko; Maeda, Makoto; Katabuchi, Tatsuya*

JAEA-Conf 2023-001, p.74 - 79, 2024/02

https://doi.org/10.11484/jaea-conf-2023-001

Water contents in aggregates and cement pastes determined by gravimetric analysis and prompt -ray analysis

Kinoshita, 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

https://doi.org/10.1007/s10967-023-08776-w

Investigation of radioactive samples for neutron capture reaction measurements using energy-resolved neutron imaging

Segawa, Mariko; Toh, Yosuke; Kai, Tetsuya; Kimura, Atsushi; Nakamura, Shoji

Annals of Nuclear Energy, 167, p.108828_1 - 108828_5, 2022/03

https://doi.org/10.1016/j.anucene.2021.108828

Nondestructive quantitative analysis of difficult-to-measure radionuclides Pd and Tc

Toh, Yosuke; Segawa, Mariko; Maeda, Makoto; Tsuneyama, Masayuki*; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Ebihara, Mitsuru*

Analytical Chemistry, 93(28), p.9771 - 9777, 2021/07

https://doi.org/10.1021/acs.analchem.1c01233

Feasibility study of PGAA for boride identification in simulated melted core materials

Tsuchikawa, Yusuke; Abe, Yuta; Oishi, Yuji*; Kai, Tetsuya; Toh, Yosuke; Segawa, Mariko; Maeda, Makoto; Kimura, Atsushi; Nakamura, Shoji; Harada, Masahide; et al.

JPS Conference Proceedings (Internet), 33, p.011074_1 - 011074_6, 2021/03

https://doi.org/10.7566/JPSCP.33.011074

In the decommissioning of the Fukushima-Daiichi (1F) Nuclear Power Plant, it is essential to understand characteristics of the melted core materials. The estimation of boride in the real debris is of great importance to develop safe debris removal plans. Hence, it is required to investigate the amount of boron in the melted core materials with nondestructive methods. Prompt gamma-ray activation analysis (PGAA) is one of the useful techniques to determine the amount of borides by means of the 478 keV prompt gamma-ray from neutron absorption reaction of boron. Moreover, it is well known that the width of the 478 keV gamma-ray peak is typically broadened due to the Doppler effect. The degree of the broadening is affected by coexisting materials, and can be recognized by the width of the prompt gamma-ray peak. As a feasibility study, the prompt gamma-ray from boride samples were measured using the ANNRI, NOBORU, and RADEN beamlines at the Materials and Life Science Experimental Facility (MLF) of Japan Proton Accelerator Complex (J-PARC).

Development of event-type neutron imaging detectors at the energy-resolved neutron imaging system RADEN at J-PARC

Parker, J. D.*; Harada, Masahide; Hayashida, Hirotoshi*; Hiroi, Kosuke; Kai, Tetsuya; Matsumoto, Yoshihiro*; Nakatani, Takeshi; Oikawa, Kenichi; Segawa, Mariko; Shinohara, Takenao; et al.

Materials Research Proceedings, Vol.15, p.102 - 107, 2020/05

https://doi.org/10.21741/9781644900574-17

Feasibility study of two-dimensional neutron-resonance thermometry using molybdenum in 316 stainless-steel

Kai, Tetsuya; Hiroi, Kosuke; Su, Y. H.; Segawa, Mariko; Shinohara, Takenao; Matsumoto, Yoshihiro*; Parker, J. D.*; Hayashida, Hirotoshi*; Oikawa, Kenichi

Materials Research Proceedings, Vol.15, p.149 - 153, 2020/02

https://doi.org/10.21741/9781644900574-23