研究者詳細 - 瓜谷　章

講演・口頭発表等 - 瓜谷　章

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名古屋大学における静電陽子加速器を用いたホウ素中性子捕捉療法用中性子施設の現状

鬼柳善明，土田一輝，釣田幸夫，古澤大貴，佐藤和也，山﨑淳，吉橋幸子，渡辺賢一，瓜谷章，恒吉達矢，辻義之，市川豪，伊藤維久弥，今城想平，土川雄介，広田克也，北口雅暁，清水裕彦

第14回日本加速器学会年会

開催年月日： 2017年8月

記述言語：日本語会議種別：ポスター発表

開催地：北海道大学クラーク会館国名：日本国

名古屋大学では、静電陽子加速器ダイナミトロン（定格2.8MeV、15mA）をベースとした、医理工応用を目指した中性子施設NUANS（Nagoya University Accelerator-driven Neutron Source）を建設中である。第一ビームラインがボロン中性子捕捉療法（BNCT）用、第二ビームラインが理工応用である。この施設の第一の目的は、低エネルギー加速器と密封型リチウムターッゲトを用いたシステムによって、BNCTが可能かどうかを工学的観点から明らかにすることである。そのため、中性子ビーム線質、ターゲットの健全性などについて検討を行う。加速器は、2mAの電流値を達成した本年5月に施設検査を受け、陽子ビーム照射実験が可能となった。今後、加速器パワーの増加とともに、BNCT用高出力ターゲット開発のための陽子照射実験を進めて行く予定である。次の段階として年内の中性子発生を目指している。ターゲットとしては、第一ビームラインではベリリウムとリチウムターゲットを、また、第二ビームラインではベリリウムを使用する。それぞれの加速器パワーの上限が異なるため、それに応じた建屋の放射線線量評価を行った。さらに、BNCT用中性子源の高性能化、徐熱の高度化を行っている。本報告では、加速器、BNCT用システムの開発状況など施設の現状について報告する。

Development of Beam Shaping Assembly with extension collimator for Accelerator-based BNCT System in Nagoya University 国際会議

Kazuya SATO, Akira URITANI, Kenichi WATANABE, Sachiko YOSHIHASHI, Atsushi YAMAZAKI, Yoshiaki KIYANAGI, Kazuki TSUCHIDA and Hirohiko SHIMIZU

International Conference on Neutron Optics 2017

Construction of Nagoya University Accelerator-driven Neutron Source (NUANS) 2nd beamline 国際会議

Koichi Kino, Setsuo Sato, Kenichi Watanabe, Akira Uritani, Sachiko Yoshihashi, Atsushi Yamazaki, Yuichi Ikeda, Kentaro Fukuda

International Conference on Neutron Optics 2017

開催年月日： 2017年7月

記述言語：英語会議種別：ポスター発表

開催地：Nara, Japan 国名：日本国

We have developed a neutron detection using Transparent RUbber SheeT type Eu:LiCaAlF₆ (TRUST Eu:LiCAF) scintillator, in which small pieces of Eu:LiCAF scintillator is dispersed into the transparent rubber. The TRUST Eu:LiCAF is simple to make it large size because it can be fabricated with a rubber molding process. It is, therefore, suitable to combine with WaveLength Shifting Fiber (WLSF) which can collect scintillation photons from a large area detector. In this paper, we are developing a long detector with one-dimensional position sensitivity. One of the methods to obtain a one-dimensional detection position in the WLSF is to use the ratio between signal pulse heights obtained at the both ends. However, the light attenuation length in the optical fiber is generally too long to determine a detection position precisely. Applying appropriate optical processing in the fibers, we can make the signal difference large.
We fabricated the one-dimensional position sensitive detector with 1000 mm long using 19 WLSFs of 1 mm diameter. Each fiber was divided into two pieces with a reflective face and has all different divided fractions. Since the divided fractions are distributed with equal interval of 50 mm through detector, the signal pulse heights at each end gradually change with the detection position. We experimentally confirmed the position sensitivity of the fabricated detector. The relative position resolution with respect to the fiber length was evaluated to be 16% as FWHM in neutron irradiation tests using Cf-252 source surrounded with polyethylene moderator.

Development of Beam Shaping Assembly for Accelerator-based BNCT System in Nagoya University 国際会議

Akira URITANI, Yosuke MENJO, Kazuya SATO, Kenichi WATANABE, Sachiko YOSHIHASHI, Atsushi YAMAZAKI, Yoshiaki KIYANAGI, Kazuki TSUCHIDA and Hirohiko SHIMIZU

International Conference on Neutron Optics 2017

開催年月日： 2017年7月

記述言語：英語会議種別：ポスター発表

開催地：Nara, Japan 国名：日本国

An accelerator-driven compact neutron source for Boron Neutron Capture Therapy (BNCT) has been developed in Nagoya University since 2013. A Dynamitron accelerator and a Li target are used to generate neutrons. The ⁷Li(p, n)⁷Be reaction produce neutrons. Since the generated neutrons have considerably high energy, up to a few hundred keV, it is necessary to lower the neutron energy to an epi-thermal region that is suitable for BNCT. In this work, we have designed a Beam Shaping Assembly (BSA) that lowers the neutron energy and makes beam-like neutrons. The consists of a MgF₂ moderator, a lead reflector, a radiation shield and a neutron collimator. The PHITS (Ver.2.660) code has been used to simulate the neutron transport in the BSA. This paper mainly describes two issues. One is optimization of the shape of the BSA, mainly the moderator, and the other is the dependence of the calculation results on the nuclear data, JENDL-4.0 and ENDF/B-VII.1.

Development of One-Dimensional Position-Sensitive Neutron Detector Using TRUST Eu:LiCAF Scintillator 国際会議

Hiroaki SHIMIZU, Koichi KINO, Setsuo SATO, Kenichi WATANABE, Akira URITANI, Sachiko YOSHIHASHI and Atsushi YAMAZAKI

International Conference on Neutron Optics 2017

開催年月日： 2017年7月

記述言語：英語会議種別：口頭発表（一般）

開催地：Nara, Japan 国名：日本国

We developed a one-dimensional position-sensitive neutron detector using a Transparent RUbber SheeT type Eu:LiCaAlF₆ (TRUST Eu:LiCAF) scintillators and a newly proposed wavelength shifting fiber (WLSF) readout. The proposed position-sensitive WLSF readout consists of a number of the WLSFs optically divided to distinguish a scintillation position. We experimentally compared the position sensitivities of the optically divided WLSF type detector and the conventional one using light attenuation in the WLSFs. We concluded that the proposed detector had higher spatial resolution than that of the conventional one. We, additionally, fabricated the prototype detector of the optically divided WLSF type detector. We confirmed that the fabricated detector had the relative spatial resolution of approximately 20 %.

Neutron Diagnostics in the Large Helical Devic 国際会議

M. Isobe, K. Ogawa, T. Nishitani, H. Miyake, T. Kobuchi, N. Pu, H. Kawase, E. Takada, T. Tanaka, S.Y. Li, S. Yoshihashi, A. Uritani, Murakami, M. Osakabe and the LHD Experiment Group

IEEE Symposium on Fusion Engineering

開催年月日： 2017年6月

記述言語：英語会議種別：口頭発表（一般）

開催地：Shanghai Marriott Hotel City Centre Shanghai, China 国名：日本国

Deuterium operation of LHD and expected neutron emission rate
Overview of neutron diagnostics prepared for LHD
Neutron flux monitor -In situ calibration by using
²⁵²Cf source -Initial measurement results
Neutron activation system
Vertical neutron camera
Triton burnup study

熱外領域中性子エネルギースペクトルの測定法に関する一提案

瓜谷章，渡辺賢一，山﨑淳，須田直樹，吉橋幸子

平成29年度京都大学原子炉実験所専門研究会　「京都大学原子炉実験所のBNCT拠点としての効率化・高度化に関する研究会」

名古屋大学加速器BNCT施設の開発状況

瓜谷章，渡辺賢一，山﨑淳，佐藤和也，古澤大貴，辻義之，恒吉達也，鬼柳善明，土田一輝，清水裕彦，北口雅暁，広田克也，市川豪，今城想平，吉橋幸子，若林俊彦，伊藤善之

平成29年度京都大学原子炉実験所専門研究会　「京都大学原子炉実験所のBNCT拠点としての効率化・高度化に関する研究会」

Development of Nagoya University Accelerator-driven Compact Neutron Source (NUANS) 国際会議

Katsuya Hirota, S. Imajo, G. Ichikawa, I. Itoh, M. Kitaguchi, H. M. Shimizu, Y. Tsuchikawa, Y. Kiyanagi, K. Tsuchida, A. Uritani, K. Watanabe, S. Yoshihashi, A. Yamazaki, Y. Iwashita, Y. Yamagata3 and JCANS Collaboration

8th International Particle Accelerator Conference

コンクリート内部を可視化する後方散乱X線イメージング装置の開発（２）検出器開発

大橋和也、瓜谷章、渡辺賢一、山崎淳、豊川弘之、藤原健、萬代新一、伊佐英範

日本原子力学会2017年春の年会

名古屋大学における加速器BNCT用システム開発(2)Beam Shaping Assemblyの最適設計

佐藤和也、瓜谷章、渡辺賢一、吉橋幸子、市川豪、広田克也、北口雅暁、清水裕彦、鬼柳善明、土田一輝

日本原子力学会2017年春の年会

名古屋大学における加速器BNCT用システム開発 (1)全体計画とその進捗について

瓜谷章、土田一輝、鬼柳善明、佐藤和也、渡辺賢一、吉橋幸子、山﨑淳、広田克也、清水裕彦、北口雅暁

日本原子力学会2017年春の年会

コンクリート内部を可視化する後方散乱X線イメージング装置の開発（1）概要と全体システム

豊川弘之、藤原健、萬代新一、伊佐英範、大橋和也、山崎淳、渡辺賢一、瓜谷章

日本原子力学会2017年春の年会

多重球殻構造を有する単一減速材球型中性子スペクトロメータのエネルギー応答に関する検討

水越友亮、渡辺賢一、山﨑淳、瓜谷章、尾方智洋、村松貴史2

日本原子力学会2017年春の年会

TRUST Eu:LiCAFを用いた一次元位置敏感型中性子検出器の開発

志水裕昭、木野幸一、佐藤節夫、渡辺賢一、山崎淳、吉橋幸子、瓜谷章

日本原子力学会2017年春の年会

BNCT用Beam Shaping Assemblyのγ線混入率に関する検討

佐藤和也, 瓜谷章, 渡辺賢一, 吉橋幸子, 山崎淳, 市川豪, 広田克也, 北口雅暁, 清水裕彦, 鬼柳善明, 土田一輝

日本原子力学会中部支部　第48回研究発表会

大型ヘリカル装置における放射化法を用いた中性子総発生量計測システムの感度校正

田中智代, 李思遠, 普能, 瓜谷章, 渡辺賢一, 吉橋幸子, 山崎淳, 磯部光孝, 小川国大, 西谷健夫

日本原子力学会中部支部　第48回研究発表会

³He代替位置敏感型中性子検出器の開発

志水裕昭, 木野幸一, 佐藤節夫, 瓜谷章, 渡辺賢一, 吉橋幸子, 山崎淳

日本原子力学会中部支部　第48回研究発表会

Basic study of a Compton imaging using pixelated TlBr detectors

Motohiro Matsumura, Kenichi Watanabe, Atsushi Yamazaki, Sachiko Yoshihashi, Akira Uritani, Hiroki Sunaba, Nobumichi Nagano and Keitaro Hitomi

12th International Workshop on Ionizing Radiation Moitoring

開催年月日： 2016年12月

記述言語：英語会議種別：ポスター発表

国名：日本国

Compton scattering cameras have exciting potentials for wide applications such as medical imaging, radioactive decontamination and so on. Thallium bromide (TlBr) is one of the promising candidates for detectors in the Compton scattering camera because they operate stably at room temperature and have good energy resolutions for gamma rays.
The requirements for constructing Compton scattering cameras include good energy resolutions and good position resolutions for incident gamma rays. In case of pixelated detectors, the energy and position resolutions for near-anode events become worse because the pulse height decreases due to the weighting potential distortion. Charge-sharing events in adjacent pixels also contribute to deterioration of the energy and position resolutions. Therefore, development of pulse waveform analysis methods is necessary for using the pixelated TlBr detectors for the Compton scattering cameras.
In this paper, we show that the pixelated TlBr detector was operated as the Compton scattering camera. Figure 1 shows an experimental geometry. The waveforms were obtained from the four pixels, the surrounding electrode and the cathode, with a digitizer. The experiment was run at room temperature. The digital signals from the detector were processed to estimate the positions of interactions and correcting the pulse heights of signals with the depth, off-line. Images reconstructed from two-pixel events on the diagonal line are illustrated in Figs. 2 and 3. The images of the source position were successfully reconstructed using the pixelated TlBr detectors at room temperature.

A wide X-ray image sensor with extended field of view for backscattered X-ray imaging

Kazuya Ohashi, Kenichi Watanabe, Atsushi Yamazaki, Akira Uritani, Hiroyuki Toyokawa, Takeshi Fujiwara, Hidenori Isa and Shinichi Mandai

12th International Workshop on Ionizing Radiation Moitoring

開催年月日： 2016年12月

記述言語：英語会議種別：ポスター発表

国名：日本国

Routine inspections and maintenances for aged infrastructures, such as bridges and tunnels, are required. One of the methods of non-destructive inspections is X-ray imaging. Transmission X-ray imaging inspection is, however, difficult for large structures because an X-ray source and a detector should be set across a huge object. Backscattered X-ray imaging technique can inspect a large structure from one side.
We have developed a wide one-dimensional X-ray line sensor for the backscatter X-ray imaging inspection. This sensor consists of cadmium tungstate (CdWO₄, CWO) scintillator sticks and stainless steel collimator plates. Each CWO stick is sandwiched between the collimator plates. Fan-beam X-rays is irradiated perpendicular to the collimator plates and to the object. The backscattered X-rays are detected with the CWO sticks. Since the field of view of each scintillator is restricted with the collimator plates, the one-dimensional backscattered X-ray profile is acquired. A two-dimensional image can be obtained by scanning the line sensor and the X-ray source.
In order to extend the field of view of this line sensor, we increased the number of the CWO sticks. In order to increase the freedom of the configuration for scintillation light signal readout, we applied an optical fiber readout system. An end surface of each CWO stick is connected to an optical fiber and scintillation signals are detected at another end of the optical fiber.
In order to check the performance of the fabricated system, we measured a concrete block having an iron rod inside.₄

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