Am neutron capture cross section in the keV region using Si and Fe-filtered neutron beams

Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Katabuchi, Tatsuya*; Kodama, Yu*; Nakano, Hideto*

Journal of Nuclear Science and Technology, 60(5), p.489 - 499, 2023/05

https://doi.org/10.1080/00223131.2022.2116496

Am neutron capture cross section measurement using the NaI(Tl) spectrometer of the ANNRI beamline of J-PARC

Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Katabuchi, Tatsuya*; Kodama, Yu*; Nakano, Hideto*; Sato, Yaoki*

Journal of Nuclear Science and Technology, 19 Pages, 2023/00

https://doi.org/10.1080/00223131.2023.2239885

Am neutron capture cross section measurement and resonance analysis

Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Katabuchi, Tatsuya*; Kodama, Yu*; Nakano, Hideto*; Sato, Yaoki*

JAEA-Conf 2022-001, p.91 - 96, 2022/11

https://doi.org/10.11484/jaea-conf-2022-001

Evaluation of detector performances of new thin position-sensitive scintillation detectors for SENJU diffractometer

Nakamura, Tatsuya; To, Kentaro; Koizumi, Tomokatsu; Kiyanagi, Ryoji; Ohara, Takashi; Ebine, Masumi; Sakasai, Kaoru

Proceedings of 2022 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room Temperature Semiconductor Detector Conference (2022 IEEE NSS MIC RTSD) (Internet), 2 Pages, 2022/11

https://doi.org/10.1109/NSS/MIC44845.2022.10399279

A new thin position-sensitive scintillation neutron detectors have been developed to replace present scintillation detectors in SENJU diffractometer at J-PARC MLF. The SENJU diffractometer originally composed of 37 position-sensitive detectors, where each detector has neutron sensitive area of 256 256 mm with a pixel size of 4 4 mm. To renew some original detectors the new detectors have been developed based on ZnS scintillator and wavelength-shifting fibers technology. The developed replacement detectors were designed with a thin thickness of 12 cm, which is 40% of the original detector. The new detectors have also improved detector performances to the original ones in terms of detection efficiency (60% for 2-A neutrons) and count uniformity (5-8%). The produced six detector modules have been implemented to the beamline after checking their detector performances in the lab.

KeV-neutron capture cross-section measurement of Au with a Cr-filtered neutron beam at the ANNRI beamline of MLF/J-PARC

Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Katabuchi, Tatsuya*; Kodama, Yu*; Nakano, Hideto*; Sato, Yaoki*; et al.

Journal of Nuclear Science and Technology, 59(5), p.647 - 655, 2022/05

https://doi.org/10.1080/00223131.2021.1997666

Development of a neutron beam monitor for nuclear data measurement using spallation neutron source

Nakano, Hideto*; Katabuchi, Tatsuya*; Rovira Leveroni, G.*; Kodama, Yu*; Terada, Kazushi*; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke

JAEA-Conf 2021-001, p.166 - 170, 2022/03

https://doi.org/10.11484/jaea-conf-2021-001

KeV-region analysis of the neutron capture cross-section of Np

Rovira Leveroni, G.; Katabuchi, Tatsuya*; Tosaka, Kenichi*; Matsuura, Shota*; Kodama, Yu*; Nakano, Hideto*; Iwamoto, Osamu; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Nobuyuki

Journal of Nuclear Science and Technology, 59(1), p.110 - 122, 2022/01

https://doi.org/10.1080/00223131.2021.1954104

Two-dimensional scintillation neutron detectors for the extension of SENJU diffractometer

Nakamura, Tatsuya; To, Kentaro; Koizumi, Tomokatsu; Kiyanagi, Ryoji; Ohara, Takashi; Ebine, Masumi; Sakasai, Kaoru

Proceedings of 2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2020), Vol.1, p.483 - 484, 2021/09

https://doi.org/10.1109/NSS/MIC42677.2020.9507813

Two-dimensional neutron detectors were developed for the extension of SENJU time-of-flight Laue single crystal neutron diffractometer in J-PARC MLF. The detectors are to be installed at the additional detector bank for the SENJU instrument. The detector module is made based on ZnS scintillator and wavelength-shifting fiber technology, where each detector module maintains a neutron-sensitive area of 256256 mm with a pixel size of 44 mm. To meet the tight space limitation in the instrument, the detector was designed as compact as possible. The detector has a depth of 170 mm, which is about 40% smaller than that of the original SENJU detector. All four produced detectors exhibited similar detector performances: detection efficiency 50-60% for 2- neutron, Co gamma-ray sensitivity 110, count uniformity 3-6%.

Research and examination of seismic safety evaluation and function maintenance for important equipment in nuclear facilities

Furuya, Osamu*; Fujita, Satoshi*; Muta, Hitoshi*; Otori, Yasuki*; Itoi, Tatsuya*; Okamura, Shigeki*; Minagawa, Keisuke*; Nakamura, Izumi*; Fujimoto, Shigeru*; Otani, Akihito*; et al.

Proceedings of ASME 2021 Pressure Vessels and Piping Conference (PVP 2021) (Internet), 6 Pages, 2021/07

Since the Fukushima accident, with the higher safety requirements of nuclear facilities in Japan, suppliers, manufacturers and academic societies have been actively considering the reconstruction of the safety of nuclear facilities from various perspectives. The Nuclear Regulation Authority has formulated new regulatory standards and is in operation. The new regulatory standards are based on defense in depth, and have significantly raised the levels of natural hazards and have requested to strengthen the countermeasures from the perspective of preventing the simultaneous loss of safety functions due to common factors. Facilities for dealing with specific serious accidents are required to have robustness to ensure functions against earthquakes that exceed the design standards to a certain extent. In addition, since the probabilistic risk assessment (PRA) and the safety margin evaluation are performed to include the range beyond the design assumption in the safety improvement evaluation, it is very important to extent the special knowledge in the strength of important equipment for seismic safety. This paper summarizes the research and examination results of specialized knowledge on the concept of maintaining the functions of important seismic facilities and the damage index to be considered by severe earthquakes. In the other paper, the study on reliability of seismic capacity analysis for important equipment in nuclear facilities will be reported.

Mode distribution analysis for superionic melt of CuI by coherent quasielastic neutron scattering

Kawakita, Yukinobu; Kikuchi, Tatsuya*; Tahara, Shuta*; Nakamura, Mitsutaka; Inamura, Yasuhiro; Maruyama, Kenji*; Yamauchi, Yasuhiro*; Kawamura, Seiko; Nakajima, Kenji

JPS Conference Proceedings (Internet), 33, p.011071_1 - 011071_6, 2021/03

BB2019-1144.pdf:0.7MB

https://doi.org/10.7566/JPSCP.33.011071

CuI is a well-known superionic conductor in a high temperature solid phase where the mobile cations migrate between interstitial sites in the f.c.c. sublattice formed by iodine ions. Even in the molten state, it shows several features suggesting collective or cooperative ionic motion. MD results show that Cu diffuses much faster than I. The Cu-Cu partial structure factor have a FSDP which indicates a medium-range ordering of Cu ions. Moreover the Cu-Cu partial pair distribution deeply penetrates into the nearest neighboring Cu-I shell. To reveal origin such anomalous behaviors of molten CuI, we performed quaiselastic neutron scattering (QENS) by the disk-chopper spectrometer AMATERAS at MLF, J-PARC. To interpret the total dynamic structure factor obtained from coherent QENS, the mode distribution analysis was applied. It is found that the motion of iodine is a kind of fluctuating within an almost local area while Cu ions diffuse much faster than iodine ions.