Kazuhiko Soyama

Japan Atomic Energy Agency

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Co-Authors

Dai Yamazaki

The University of Tokyo

Ryuji Maruyama

Kameda Medical Center

K. Sakasai

Japan Atomic Energy Agency

Takayuki Oku

Japan Atomic Energy Agency

K. Toh

Japan Proton Accelerator Research Complex

Masahide Harada

Japan Proton Accelerator Research Complex

Kenichi Oikawa

Japan Atomic Energy Agency

T. Nakamura

Japan Atomic Energy Agency

H. Yamagishi

Nippon Institute of Technology

Kazuya Aizawa

Japan Atomic Energy Agency

Cooperative Institutions

Japan Atomic Energy Agency

193

Japan Proton Accelerator Research Complex

158

High Energy Accelerator Research Organization

Guangdong Technion-Israel Institute of Technology

The University of Tokyo

University of Wollongong

Tohoku University

Advanced Science Research Center

Comprehensive Research Organization for Science and Society

Technical University of Munich

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Neutron Transmission CB-KID Imager Using Samples Placed at Room Temperature

Journal of Low Temperature Physics (2024)

Takekazu Ishida The Dang Vu Hiroaki Shishido Kazuya Aizawa Takayuki Oku

10.1007/s10909-023-03030-9

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Superconducting neutron transmission imaging for investigating a sequential change in phase separations of low-melting Wood’s metal

Journal of Physics Conference Series (2023)

The Dang Vu Hiroaki Shishido Kazuya Aizawa Takayuki Oku Kenichi Oikawa

Abstract We built a new cryostat system for a current-biased kinetic inductance detector (CB-KID) to be able to place a sample at room temperature for conducting the neutron transmission imaging experiments with pulsed neutrons. A Wood’s metal alloy sample (Bi 50wt.%, Pb 25wt.%, Sn 12.5wt.%, Cd 12.5wt.%) of melting temperature 75.2°C was used to check a practical test by observing fine microstructures under beam power of 812 kW at beamline BL10 of J-PARC (MLF). The Wood’s metal is composed of four phases, of which one is a Cd-rich needle-like phase of an average width of 25 µm and length of 5 mm. Since Cd is a strong neutron absorber, it is suitable for observing the fine mosaic structure contrastingly in neutron transmission imaging. After neutron-transmission imaging with the Wood’s metal in the initial state, we subsequently melted the Wood’s metal sample and solidified it again by slow cooling during the same beam time. We were successful in observing an impressive change in morphology of the phases by neutron-transmission imaging. Room-temperature sample imaging is very convenient for possible users, and is expected to be very useful for applying our CB-KID system to versatile different materials of interests.

Neutron Imaging

Neutron radiation

10.1088/1742-6596/2545/1/012019

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Development of a³He nuclear spin flip system on an in-situ SEOP³He spin filter and demonstration for a neutron reflectometer and magnetic imaging technique

Journal of Physics Conference Series (2016)

Hirotoshi Hayashida Takayuki Oku H. Kira K. Sakai Kosuke Hiroi

We have been developing a 3He neutron spin filter (NSF) using the spin exchange optical pumping (SEOP) technique. The 3He NSF provides a high-energy polarized neutron beam with large beam size. Moreover the 3He NSF can work as a π-flipper for a polarized neutron beam by flipping the 3He nuclear spin using a nuclear magnetic resonance (NMR) technique. For NMR with the in-situ SEOP technique, the polarization of the laser must be reversed simultaneously because a non-reversed laser reduces the polarization of the spin-flipped 3He. To change the polarity of the laser, a half-wavelength plate was installed. The rotation angle of the half-wavelength plate was optimized, and a polarization of 97% was obtained for the circularly polarized laser. The 3He polarization reached 70% and was stable over one week. A demonstration of the 3He nuclear spin flip system was performed at the polarized neutron reflectometer SHARAKU (BL17) and NOBORU (BL10) at J-PARC. Off-specular measurement from a magnetic Fe/Cr thin film and magnetic imaging of a magnetic steel sheet were performed at BL17 and BL10, respectively.

Optical Pumping

Neutron radiation

Helium-3

10.1088/1742-6596/711/1/012007

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Citations (5)

Dimensional Stability of Uranium Silicide Plate-Type Reactors at Transient Condition

Journal of Nuclear Science and Technology (1992)

Kazuaki YANAGISAWA Toshio FUJISHIRO Oichiro Horiki Kazuhiko Soyama Hiroki Ichikawa

This paper describes the result of transient experiments using low enriched uranium silicide plate-type fuel for research reactors. The pulse irradiation was carried out at Nuclear Safety Research Reactor (NSRR) in Japan Atomic Energy Research Institute. The results obtained were: 1. At fuel plate temperature of below 400°C, a good dimensional stability of the tested fuel was kept. No fuel failure occurred.2. At a plate temperature of about 540°C, a local crack was initiated on the AI-3%Mg alloy cladding. Once the cladding temperature exceeded the melting point of 640°C, the fuel plate was degraded much by increased bowing and cracking of the denuded fuel meat occurred after relocation of molten Al cladding. Despite of these degradation, neither fragmentation of the fuel plate nor mechanical energy generation occurred up to the cladding temperature of 971 °C.3. At the temperatures of around 925°C, the reaction of silicide particles with molten Al in the matrix and that of cladding occurred, forming Al riched U (Al, Si) compounds and Si riched (U, Si) compounds at the outermost surface of the silicide particles.

Cladding (metalworking)

Nuclear Fuel

Uranium dioxide

Uranium oxide

10.1080/18811248.1992.9731518

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Citations (9)

A beam divergence correction mirror for neutron resonance spin echo

Physica B Condensed Matter (2009)

Ryuji Maruyama Masahiro Hino Hirotoshi Hayashida Masaaki Kitaguchi N. Achiwa

Neutron spin echo

Echo (communications protocol)

Divergence (linguistics)

10.1016/j.physb.2009.06.036

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Citations (4)

Development of gas-based 2-dimensional neutron detector with individual line readout and optical signal transmission system

K. Toh Takemi Nakamura K. Sakasai Kazuhiko Soyama H. Yamagishi

A signal processing system for a gas-based 2-dimensional neutron detector that uses an individual line readout method was developed. In the system, optical devices were adopted for a long-distance signal transmission and insulation between a detector head in a neutron shielding and signal processing circuits in a data acquisition room. It was confirmed by experiments with and without neutron irradiation that the whole system operated satisfactory and a pulse pair resolution of our system was less than Ills.

SIGNAL (programming language)

Neutron Detection

Line (geometry)

10.1109/nssmic.2012.6551082

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Optimization of a micro-strip gas chamber as a two-dimensional neutron detector using gadolinium converter

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (2003)

Sei Masaoka Tatsuya Nakamura H. Yamagishi Kazuhiko Soyama

Neutron Detection

Neutron Imaging

Position (finance)

10.1016/s0168-9002(03)02077-1

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Citations (13)

Pulsed Laser Deposition Diamond-Like Carbon Guides for use in Polarized Ultracold Neutron Transport

APS (2001)

M. Makela M. Pitt R. B. Vogelaar A. Pichlmaier U. Pesavento

Ultracold neutrons

Deposition

Carbon fibers

Pulsed Laser Deposition

Diamond-like carbon

Source

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Effects of gamma-rays on polymethylmethacrylate plastic optical fiber under low dose-rate irradiation

IEEE Nuclear Science Symposium conference record (2011)

K. Toh T. Nakamura K. Sakasai Kazuhiko Soyama

An irradiation test was performed for polymethylmethacrylate (PMMA) plastic optical fibers (POFs) under low dose-rate gamma-ray irradiation in order to use the fiber in low-level radiation environments. Radiation-induced loss that has peaks in the ultraviolet and near infrared wavelength range and improvement in the optical transmission over an entire wavelength range were observed under the irradiation. The peak intensity of the induced loss increases with the absorbed dose, and the intensity saturate at some absorbed doses. The absorbed dose at which the intensity becomes saturated depends on the gamma-ray dose rate. Therefore, it is necessary to take into account the dose rate when the PMMA POF used as a dosimeter in low level gamma-ray irradiation. The improvement in the optical transmission is dependent on the radiation dose rate and become large in lower gamma-ray dose rate.

Ultraviolet

Dose rate

Intensity

10.1109/nssmic.2011.6154515

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Citations (1)

Fabrication and characterization of NiC/Ti supermirror

Kazuhiko Soyama M. Suzuki

Characterization

Source

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