研究者詳細 - 吉橋　幸子

Development of thermal neutron moderator for testing boron agents for Boron Neutron Capture Therapy (BNCT)

Ichikawa, G; Tsuchida, K; Kiyanagi, Y; Ishikawa, A; Hirata, Y; Yoshihashi, S; Watanabe, K; Uritani, A; Hamano, T; Ogawara, R; Suda, M; Igawa, K

JOURNAL OF INSTRUMENTATION 14 巻 ( 06 ) 頁： T06010 - T06010 2019年6月

中性子ブラッグエッジ解析コードRITSにおけるシングルエッジフィッティングの改良

大前良磨, 渡辺賢一, 瓜谷章, 山﨑淳, 吉橋幸子, 鬼柳善明, 佐藤博隆

応用物理学会学術講演会講演予稿集 2019.1 巻 ( 0 ) 頁： 561 - 561 2019年2月

光ファイバ型中性子検出器を用いたBNCT中性子場の計測

石川諒尚, 山﨑淳, 渡辺賢一, 吉橋幸子, 瓜谷章, 釣田幸雄, 土田一輝, 鬼柳善明

応用物理学会学術講演会講演予稿集 2019.1 巻 ( 0 ) 頁： 526 - 526 2019年2月

Response evaluation of Onion-like single Bonner sphere neutron spectrometer using TRUST Eu:LiCAF scintillator

Watanabe Kenichi, Mizukoshi Tomoaki, Yamazaki Atsushi, Yoshihashi Sachiko, Uritani Akira, Iguchi Tetsuo, Ogata Tomohiro, Muramatsu Takashi, Matsumoto Tetsuro, Masuda Akihiko

Progress in Nuclear Science and Technology 6 巻 ( 0 ) 頁： 122 - 125 2019年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Atomic Energy Society of Japan

We have developed the single sphere neutron spectrometer with five sensitive layers using the TRUST Eu:LiCAF scintillator and the WLSF readout. We evaluated the energy dependence of the detector response at thermal neutron and 24 keV, 144 keV, 565 keV, 5MeV and 14.8 MeV mono-energetic neutron irradiation fields. The experimentally determined neutron sensitivities are consistent with the Monte Carlo calculations. The detector responses for a bare and a heavy-water moderated 252Cf sources also show good agreement with the expected ones using the Monte Carlo calculations.

DOI： 10.15669/pnst.6.122

Basic evaluation of the Eu:BaFBr and Ce:CaF2 hybrid type optical fiber based dosimeter system for correction of quenching effect under carbon ion irradiation

Hirata Yuho, Watanabe Kenichi, Yamazaki Atsushi, Yoshihashi Sachiko, Uritani Akira, Koba Yusuke, Matsufuji Naruhiro, Yanagida Takayuki, Fukuda Kentaro

Progress in Nuclear Science and Technology 6 巻 ( 0 ) 頁： 238 - 242 2019年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Atomic Energy Society of Japan

We fabricated the hybrid type optical fiber based dosimeter system using Eu:BaFBr and Ce:CaF2 optically stimulated luminescence (OSL) materials in order to correct the quenching effect under high LET particle irradiation. The fabricated dosimeter probe can obtain signals from both OSL materials through one optical fiber. We investigated the probe response by irradiating it with mono-energetic carbon ions and broad-spectrum ones making the spread-out Bragg peak (SOBP). We demonstrated that the SOBP shape can be improved by correction of the quenching effect using the relationship between the luminescence efficiency and the signal intensity ratio of both OSL materials.

DOI： 10.15669/pnst.6.238

Evaluation of imaging plate measurement for activated indium as fast-neutron detector in large radiation field

Kobayashi Makoto, Nishitani Takeo, Kato Akemi, Saze Takuya, Tanaka Tomoyo, Yoshihashi Sachiko, Ogawa Kunihiro, Isobe Mitsutaka

Progress in Nuclear Science and Technology 6 巻 ( 0 ) 頁： 58 - 62 2019年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Atomic Energy Society of Japan

The application of imaging plate (IP) method using indium foils to measure the distribution of fast neutron in large area was evaluated in this work. The radioactive nuclides of indium were individually quantified by high-purity germanium detector (HPGe) and chronological IP measurements. The detection efficiencies of each radioactive nuclide for various thicknesses of foil mylar polyester film were summarized. The scope of application for proposed method were clearly dependent on the flux ratio of fast and thermal neutron, limiting the applicable region only being close to the neutron source.

DOI： 10.15669/pnst.6.58

Measurement of Thermal and Epithermal Neutron Flux Distribution in the Torus Hall of LHD using Activation Method in the First Deuterium Experiment Campaign

Tanaka Tomoyo, Kobayashi Makoto, Yoshihashi Sachiko, Uritani Akira, Watanabe Kenichi, Yamazaki Atsushi, Nishitani Takeo, Ogawa Kunihiro, Isobe Mitsutaka

PLASMA AND FUSION RESEARCH 14 巻 ( 0 ) 頁： 3405162 - 3405162 2019年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人プラズマ・核融合学会

In the Large Helical Device (LHD) of the National Institute for Fusion Science, a deuterium plasma experiment was performed in March 2017. Neutrons with an energy of 2.45 MeV are generated by d (d, n) 3He reactions. The evaluation of this neutron flux in the torus hall, as well as within the LHD vessel, is very important for the decommissioning of the LHD in the future and the radiation shielding for workers and components around the LHD. In this study, we evaluate the spatial distribution of thermal and epithermal neutron flux on the floor level of the LHD torus hall by measuring the neutron activation of gold foils. The flux information obtained in the experiment can be used for the evaluation of radio-activation and the shielding design.

DOI： 10.1585/pfr.14.3405162

Numerical heat transfer study of turbulent square-duct flow through inline V-shaped discrete ribs

Yu Stu. Shichao, Tsuneyoshi Tatsuya, Yoshihashi Sachiko, Hamaji Yukinori, Ito Takahiro, Tsuji Yoshiyuki

流体工学部門講演会講演論文集 2019 巻 ( 0 ) 頁： OS8-07 - 7 2019年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本機械学会

A numerical study has been conducted to examine turbulent flow and heat transfer characteristics in a three-dimensional square-duct with V-shaped ribs. The computations are based on RANS and LES models. Water is the working fluid with the flow rate of which Reynolds numbers equals to 18500. The computation reveals that two symmetrical fully developed helical flow and developed heat transfer profile are generated. Effects of different rib shape on thermal characteristics for a ribbed duct flow are investigated. The change of the shape leads to increase in heat transfer and pressure loss. The velocity profile in the vicinity of ribs and streamline has been investigated, indicates that the different flow structures generated by the rib shape leads to superior heat transfer performance. Vortices are visualized, which indicates the connection between the heat transfer and flow structure

DOI： 10.1299/jsmefed.2019.os8-07

First measurements of thermal neutron distribution in the LHD torus hall generated by deuterium experiments Open Access

Kobayashi, M; Tanaka, T; Nishitani, T; Ogawa, K; Isobe, M; Kato, A; Saze, T; Yoshihashi, S; Osakabe, M

FUSION ENGINEERING AND DESIGN 137 巻頁： 191 - 195 2018年12月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Fusion Engineering and Design

For the estimation of the neutron field generated by deuterium plasma operation in the Large Helical Device (LHD), the first measurement of the thermal neutron distribution on the floor level of the LHD torus hall was carried out. For the thermal neutron detection, indium was used as activation foils. The radioactivity of these foils were evaluated by a high-purity germanium detector (HPGe) and an imaging plate (IP). The major components of radioactive isotope of indium was 116mIn. The mapping of thermal neutron distribution in the torus hall was performed. The interactions between neutron and components around LHD were observed in the thermal neutron distribution. Also, the borated polyethylene blocks effectively absorbed the thermal neutron. The thermal neutron distribution evaluated in this work can be helpful to predict the amount of radioactive waste in the torus hall proceeding with deuterium experiment in LHD.

DOI： 10.1016/j.fusengdes.2018.09.013

Improved Design of the Exit of a Beam Shaping Assembly for an Accelerator-driven BNCT System in Nagoya University

Kazuya Sato, Akira Uritani, Kenichi Watanabe, Sachiko Yoshihashi, Atsushi Yamazaki, Yoshiaki Kiyanagi, Kazuki Tsuchida

Proceedings of the International Conference on Neutron Optics (NOP2017) 2018年11月

Calibration experiment and the neutronics analyses on the LHD neutron flux monitors for the deuterium plasma experiment

Nishitani, T; Ogawa, K; Isobe, M; Kawase, H; Pu, N; Kashchuk, Y; Krasilnikov, V; Jo, J; Cheon, M; Tanaka, T; Yoshihashi, S; Li, SY; Osakabe, M

FUSION ENGINEERING AND DESIGN 136 巻頁： 210 - 214 2018年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Fusion Engineering and Design

Prior to the deuterium experiments of the Large Helical Device (LHD), an in situ neutron calibration experiment was carried out by using an 800 MBq 252Cf neutron source in November 2016, where a neutron flux monitor, a neutron activation system and a vertical neutron camera are calibrated. This paper concentrates on the in situ calibration for the neutron flux monitor. The neutron flux monitor based on 235U fission chambers and 10B and 3He proportional counters are positioned at three locations outside the LHD cryostat. The counts are measured during continuous rotation of the 252Cf neutron source on the typical magnetic axis of the plasma by a toy train, where the neutron source can be regarded as a ring neutron source. Detection efficiencies for the 252Cf ring source are derived by (total counts)/(total emitted neutron number) in the continuous rotation of the neutron source. Detection efficiencies for the real plasma neutron source are obtained from the measured detection efficiencies with the correction factor taking account of the deference between the 252Cf ring source and the real plasma neutron source evaluated by MCNP calculations with the three-dimensional model of the LHD. Finally, the uncertainty of the total neutron emission rate measurement is discussed.

DOI： 10.1016/j.fusengdes.2018.01.053

Neutron Diagnostics in the Large Helical Device Open Access

Isobe, M; Ogawa, K; Nishitani, T; Miyake, H; Kobuchi, T; Pu, N; Kawase, H; Takada, E; Tanaka, T; Li, SY; Yoshihashi, S; Uritani, A; Jo, J; Murakami, S; Osakabe, M

IEEE TRANSACTIONS ON PLASMA SCIENCE 46 巻 ( 6 ) 頁： 2050 - 2058 2018年6月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE Transactions on Plasma Science

The deuterium operation of the large helical device (LHD) began in March 7, 2017, after long-term preparation and commissioning of apparatuses necessary for execution of the deuterium experiment. A comprehensive set of neutron diagnostics was developed and installed onto LHD through numerous efforts in preparation. Neutron diagnostics play an essential role in both neutron yield management for the radiation safety and extension of energetic-particle physics study in LHD. Neutron flux monitor (NFM) characterized by fast-response and wide dynamic range capabilities is successfully working. Total neutron emission rate reached $3.3 \times 10^{15}$ (n/s) in the first deuterium campaign of LHD. The highest neutron emission rate was recorded in inward shifted configuration. Neutron yield evaluated by neutron activation system agrees with neutron yield measured with NFM. Performance of vertical neutron camera was demonstrated. Neutron emission profile was inwardly shifted in the inwardly shifted configuration, whereas it was outwardly shifted in the outwardly configuration. Secondary deuterium-tritium neutrons produced by triton burnup in LHD deuterium plasmas were detected for the first time in stellarator/heliotron devices in the world. Similar to total neutron emission rate, the inward shifted configuration provided highest triton burnup ratio.

DOI： 10.1109/TPS.2018.2836987

ダイバーシティってなに？

吉田浩子, 吉橋幸子

日本原子力学会誌ATOMOΣ 60 巻 ( 5 ) 頁： 303 - 306 2018年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：一般社団法人日本原子力学会

ダイバーシティ(多様性)推進委員会は，男女のジェンダーのみならず，より多角的な視野から働きやすい社会(学会)，職場を目指す活動を進めていくため2017年に男女共同参画委員会から名称を変更した。日本原子力学会会員がダイバーシティについてどのくらい認識しており，何が問題となっているかを再確認し，より良い活動のための基礎情報とするため，2017年秋の大会においてダイバーシティ推進におけるアンケート調査を実施した。本稿では，そのアンケート結果の報告と今後，本委員会で取り組んでいきたい事項について報告する。

DOI： 10.3327/jaesjb.60.5_303

Measurement of transient flow characteristics of target flow in water experiment for IFMIF

In situ calibration of neutron activation system on the large helical device Open Access

Pu, N; Nishitani, T; Isobe, M; Ogawa, K; Kawase, H; Tanaka, T; Li, SY; Yoshihashi, S; Uritani, A

REVIEW OF SCIENTIFIC INSTRUMENTS 88 巻 ( 11 ) 頁： 113302 2017年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AIP Publishing

<jats:p>In situ calibration of the neutron activation system on the Large Helical Device (LHD) was performed by using an intense 252Cf neutron source. To simulate a ring-shaped neutron source, we installed a railway inside the LHD vacuum vessel and made a train loaded with the 252Cf source run along a typical magnetic axis position. Three activation capsules loaded with thirty pieces of indium foils stacked with total mass of approximately 18 g were prepared. Each capsule was irradiated over 15 h while the train was circulating. The activation response coefficient (9.4 ± 1.2) × 10−8 of 115In(n, n′)115mIn reaction obtained from the experiment is in good agreement with results from three-dimensional neutron transport calculations using the Monte Carlo neutron transport simulation code 6. The activation response coefficients of 2.45 MeV birth neutron and secondary 14.1 MeV neutron from deuterium plasma were evaluated from the activation response coefficient obtained in this calibration experiment with results from three-dimensional neutron calculations using the Monte Carlo neutron transport simulation code 6.</jats:p>

DOI： 10.1063/1.5009475

Matsuda, S; Kanemura, T; Kondo, H; Kaji, S; Okita, T; Yoshihashi, S; Hoashi, E; Horiike, H

FUSION ENGINEERING AND DESIGN 124 巻頁： 1096 - 1100 2017年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Fusion Engineering and Design

International Fusion Material Irradiation Facility (IFMIF) is the facility generating the high flux and high energy neutrons to develop fusion reactor materials. In IFMIF, high-speed liquid lithium (Li) jet is used as the target irradiated by deuteron beams. Since the Li jet must flow with high velocity for heat removal, it is important to research on the Li flow characteristics. These researches have been aimed toward the steady-state Li flow characteristics. On the other hand, in the actual IFMIF, it is also necessary to clarify transient flow characteristics at start and stop of the system for the operation. In this study, water experiment to obtain them at start and stop is thus conducted. Water can be substituted for liquid Li as the target, because the kinematic viscosity of the Li at operation temperature in IFMIF is nearly equal to that of water at normal temperature and pressure. Flow patterns of the water jet at test section which consists of a two-staged contraction nozzle, a vertical concave flow channel are observed by laser probe method and high-speed video camera. As a result, the flow pattern at start and stop was successfully observed. The flow at stop became stable by venting gas.

DOI： 10.1016/j.fusengdes.2017.03.111