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Journal Articles

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.

Journal Articles

Introduction to nuclear security, 3; Nuclear material detection technique for nuclear security

Takahashi, Yoshiyuki*; Koizumi, Mitsuo

Nihon Genshiryoku Gakkai-Shi ATOMO, 62(8), p.452 - 456, 2020/08

no abstracts in English

Journal Articles

Sample shape effect on nuclear material quantification with neutron resonance transmission analysis

Tsuchiya, Harufumi; Ma, F.; Kitatani, Fumito; Paradella, C.*; Heyse, J.*; Kopecky, S.*; Schillebeeckx, P.*

Proceedings of 41st ESARDA Annual Meeting (Internet), p.374 - 377, 2019/05

Journal Articles

Development of active neutron NDA techniques for nonproliferation and nuclear security, 2; Study on a compact NRTA system

Tsuchiya, Harufumi; Kitatani, Fumito; Maeda, Makoto; Kureta, Masatoshi

Proceedings of INMM 57th Annual Meeting (Internet), 6 Pages, 2016/07

From a viewpoint of nuclear safeguards and nuclear security, it has recently become important to develop a non-destructive assay (NDA) system that accurately determines the amount of special nuclear materials (SNMs) in various samples such as spent fuels, next generation MA-Pu fuels and fuel debris. One candidate of those NDA techniques is neutron resonance transmission analysis (NRTA). It relies on a neutron time-of-flight measurement and is a well-established method to apply for the accurate evaluations of nuclear data, including total cross sections and resonance parameters. The potential of NRTA to quantify SNM in complex materials has been already demonstrated by performing NRTA measurement at IRMM/GELINA under collaboration of JAEA and JRC. However, a present NRTA system usually has a large electron accelerator facility to generate intense neutrons, whereas this is very difficult to apply to various facilities that need to measure SNM. Therefore a compact NRTA system would be required for practical applications of quantifying SNM in a variety of samples. In order to realize a compact NRTA system, we are developing a prototype with a D-T neutron generator that has a pulse width of 10 s and an average maximum neutron yield ranging from $10^{8}$ n/s to $2times10^{9}$ n/s. Numerical calculations were used to optimize the system performance to quantify SNM and MA in spent and MA-Pu fuels. In this presentation, those numerical calculation results, together with a brief description of the prototype, are presented. In addition, we discuss a future prospect of a compact NRTA system equipped with a neutron source with a shorter pulse width (ex. 100 ns) and a more intense neutron yield.

Journal Articles

Non-destructive depth analysis of the surface oxide layer on Mg $_{2}$ Si with XPS and XAS

Esaka, Fumitaka; Nojima, Takehiro; Udono, Haruhiko*; Magara, Masaaki; Yamamoto, Hiroyuki

Surface and Interface Analysis, 48(7), p.432 - 435, 2016/07

https://doi.org/10.1002/sia.5939

Times Cited Count：16 Percentile：39.42(Chemistry, Physical)

XPS is widely used for non-destructive chemical state analysis of solid materials. In this method, depth profiling can be carried out by a combination with ion beam sputtering. However, the sputtering often causes segregation and preferential sputtering of atoms and gives inaccurate information. The use of energy-tunable X-rays from synchrotron radiation (SR) enables us to perform non-destructive depth profiling in XPS. Here, the analytical depth can be changed by changing excitation X-ray energy. In the present study, we examined methods to perform depth profiling with XPS by changing excitation energy and XAS by changing electron energy for detection. These methods were then applied to the analysis of native surface oxide layers on Mg $_{2}$ Si crystals. In this XAS analysis, the peak at 1843.4 eV becomes dominant when the electron energy for detection increases, which implies that Si-O or Si-O-Mg structure is formed as the surface oxide layer on the Mg $_{2}$ Si.

Journal Articles

Depth analysis of the surface of Mg $_{2}$ Si crystals with XAS and XPS

Yamamoto, Hiroyuki; Nojima, Takehiro; Esaka, Fumitaka

Photon Factory Activity Report 2014, Part B, P. 112, 2015/00

http://pfwww.kek.jp/acr/2014pdf/part_b/pf14b0112.pdf

In order to develop silicon-based electronic devices, metal silicides are widely studied. Information of the surface chemical states of metal silicides is important to obtain homo-epitaxial films with excellent quality. In this work, depth analysis of surface chemical states of Mg $_{2}$ Si crystals is carried by XPS. Depth analysis is also performed in XAS measurement with a partial electron yield (PEY) mode. The Si 1s XPS spectra of the cleaved surface of the Mg $_{2}$ Si crystal indicates that SiO is formed on the surface of the Mg $_{2}$ Si crystal. Here, no peak assigned to SiO $_{2}$ structure is observed. The Si K-edge XAS spectra obtained with the PEY mode show a peak at 1843.7 eV, which can be assigned to SiO structure.

Journal Articles

Impact of systematic effects on results of neutron resonance transmission analysis

Tsuchiya, Harufumi; Harada, Hideo; Koizumi, Mitsuo; Kitatani, Fumito; Takamine, Jun; Kureta, Masatoshi; Iimura, Hideki; Kimura, Atsushi; Becker, B.*; Kopecky, S.*; et al.

Nuclear Instruments and Methods in Physics Research A, 767, p.364 - 371, 2014/12

https://doi.org/10.1016/j.nima.2014.09.009

Times Cited Count：10 Percentile：60.98(Instruments & Instrumentation)

The impact of systematic effects on the areal density derived from a neutron resonance transmission analysis (NRTA) is investigated by measurements at the time-of-flight facility GELINA. The experiments were carried out at a 25 m station using metallic natural Cu discs with different thicknesses. To derive the areal density from a fit to the experimental transmission, the resonance shape analysis code REFIT was used. Large bias effects were observed using recommended resonance parameters. Therefore, neutron resonance parameters, in particular resonance energies and neutron widths, were derived from the transmission data obtained with a 0.25 mm thick Cu metallic sample. These parameters were used to study the impact of the resonance strength and sample thickness, on the accuracy of the areal density derived by NRTA.

Journal Articles

Non-destructive depth profiling of Au/Si(100) with X-ray absorption spectroscopy

Yamamoto, Hiroyuki; Nojima, Takehiro; Esaka, Fumitaka

Photon Factory Activity Report 2013, Part B, P. 227, 2014/00

http://pfwww.kek.jp/acr2013pdf/part_b/pf13b0227.pdf

In the present study, we examined to perform depth profiling with X-ray absorption spectroscopy (XAS) by changing electron energies (5-50 eV) for detection in order to develop non-destructive depth profiling method with chemical state information. Gold thin films (1-10 nm) deposited on Si(100) were used for specimens. The Si/Au ratios were calculated from the peak heights of each edge using observed XAS spectra. Obvious correlation between the Si/Au ratio and the electron energy is observed. With decreasing electron energy, the ratio increased significantly. This means that by reducing electron energy, information on deeper region of the surface can be obtained. These results indicate that by changing electron energies for detection, it is possible to perform non-destructive depth profiling in XAS analysis.

Journal Articles