Application of deep metric learning model to microscope image analysis for the determination of UOC samples in nuclear forensics analysis

Kimura, Yoshiki; Matsumoto, Tetsuya*; Yamaguchi, Tomoki

Journal of Radioanalytical and Nuclear Chemistry, 333(7), p.3541 - 3551, 2024/07

https://doi.org/10.1007/s10967-023-09300-w

Development of training course on non-destructive assay of nuclear material for Asian region, 2; Development of lectures and exercises on gamma-ray measurement

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.

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

https://doi.org/10.1038/s41550-020-01271-2

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

The Surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.

Science, 364(6437), p.272 - 275, 2019/04

https://doi.org/10.1126/science.aav7432

The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

An Evaluation method of reflectance spectra to be obtained by Hayabusa2 Near-Infrared Spectrometer (NIRS3) based on laboratory measurements of carbonaceous chondrites

Matsuoka, Moe*; Nakamura, Tomoki*; Osawa, Takahito; Iwata, Takahiro*; Kitazato, Kohei*; Abe, Masanao*; Nakauchi, Yusuke*; Arai, Takehiko*; Komatsu, Mutsumi*; Hiroi, Takahiro*; et al.

Earth, Planets and Space (Internet), 69(1), p.120_1 - 120_12, 2017/12

AA2017-0327.pdf:1.53MB

https://doi.org/10.1186/s40623-017-0705-4

We have conducted ground-based performance evaluation tests of the Near-Infrared Spectrometer (NIRS3) onboard Hayabusa2 spacecraft and established a method for evaluating its measured reflectance spectra. Reflectance spectra of nine powdered carbonaceous chondrite samples were measured by both NIRS3 and a FT-IR spectrometer. Since raw data obtained by NIRS3 had considerable spectral distortion caused by systematic offsets in sensitivity of individual pixels, we have established two methods for correcting the NIRS3 data by comparing them with the corresponding FT-IR data. In order to characterize the absorption bands in NIRS3 spectra, the depth of each band component D is defined for each wavelength (m). Reflectance spectra of asteroid Ryugu, the target asteroid of Hayabusa2, to be recorded by the NIRS3 are expected to reveal the characteristics of the surface materials by using the evaluation technique.

Numerical estimation of Ohmic loss of high power wideband diplexer for ECCD system

Atsumi, Kohei*; Yamaguchi, Tomoki*; Nagashima, Koji*; Saigusa, Mikio*; Fukunari, Masafumi*; Oda, Yasuhisa; Sakamoto, Keishi

Plasma and Fusion Research (Internet), 8(Sp.1), p.2405077_1 - 2405077_4, 2013/06

https://doi.org/10.1585/pfr.8.2405077

Nuclear forensic analysis laboratory capability in the Integrated Support Center for Nuclear Non-proliferation and Nuclear Security at the Japan Atomic Energy Agency

Matsui, Yoshiki; Kimura, Yoshiki; Yamaguchi, Tomoki; Matsumoto, Tetsuya*; Umino, Yuji*; Hosoi, Masaharu*; Shinohara, Nobuo

no journal, , 

Nuclear and other radioactive materials outside of regulatory control (MORC) can trigger nuclear security events with severe environmental and economic consequences. In order to deal with such threats, it is necessary to strengthen international nuclear security measures, including nuclear forensics. The development of nuclear forensics technology in Japan is led by the Integrated Support Center for Nuclear Non-proliferation and Nuclear Security (ISCN) of the Japan Atomic Energy agency (JAEA) and is being carried out under domestic and international cooperation. By actively disseminating the results of its technology development to the domestic and international communities, ISCN is contributing to the improvement of nuclear forensics capabilities not only in Japan but also internationally. The present paper has discussed the status of the nuclear forensic laboratory capability in the ISCN.

The Evaluation of nuclear forensics analytical capability in the 7th Collaborative Materials Exercise of the Nuclear Forensics (CMX-7)

Matsui, Yoshiki; Kimura, Yoshiki; Umino, Yuji*; Hosoi, Masaharu*; Matsumoto, Tetsuya*; Shinohara, Nobuo; Yamazaki, Hitoshi; Yamaguchi, Tomoki

no journal, , 

The Integrated Support Center for Nuclear Nonproliferation and Nuclear Security (ISCN) of the Japan Atomic Energy Agency (JAEA) is developing technologies for nuclear forensics to identify the origin and intended use of nuclear and radioactive materials. In order to share the experience on nuclear forensics analysis and to improve analytical techniques in the international community, the Nuclear Forensics International Technical Working Group (ITWG) regularly holds the Collaborative Materials Exercise (CMX). The ISCN participated in the 7th exercise (CMX-7) this time. This paper reports the experience of the exercise, and discusses nuclear forensics analytical capability of the ISCN based on the review of the exercise.

Nuclear material identification based on electron microscope image analysis using deep learning models for nuclear forensic analysis

Kimura, Yoshiki; Matsumoto, Tetsuya*; Yamaguchi, Tomoki

no journal, , 

no abstracts in English

Application of prompt fission gamma rays to nuclear security; Measurements using approved Cf-252 devices with certification labels

Shiba, Tomooki; Sugizaki, Saki*; Yamaguchi, Tomoki

no journal, , 

The detection of prompt gamma rays (PFG) associated with nuclear fission, which is unique to nuclear materials, can be applied to the field of nuclear security. In this research, measurements using approved Cf-252 devices with certification labels are discussed.