研究者詳細 - 瓜谷　章

論文 - 瓜谷　章

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イメージングプレートとマルチピンホールコリメータを用いた３次元ガンマカメラ

瓜谷章

( 597 ) 頁： 2-5 2004年1月

Ideal Response Function of a ³He Proportional Counter to Thermal Neutrons Determined by Different Length Counters 査読有り

K. Kudo, N. Takeda, A. Uritani, S. Koshikawa, Y. Shibata, K. Kobayashi and T. Yoshimoto

Nucl. Instr. and Methods B213 巻頁： 305-309 2004年1月

記述言語：英語掲載種別：研究論文（学術雑誌）

The gas multiplication distributions along the anode wires of 3He proportional counters with different sensitive lengths of 10, 15 and 20 cm were measured using a collimated thermal neutron beam at the Kyoto University Reactor facility. The ideal response function excluding the effect of electric field distortion near the boundaries of the anode wire was derived by taking into account the difference between pulse height spectra measured by two different length counters. The pulse height spectrum calculated by the NRESPG Monte Carlo code assuming the ideal gas multiplication region showed relatively good agreement with the response function derived from the measurements. Both the energy resolution of the full energy peak at 764 keV and the peak ratio to the entire pulse height spectrum were improved markedly.

Photodisintegration of Deuterium and Big Bang Nucleosynthesis 査読有り

K. Y. Hara, H. Utsunomiya, S. Goka, H. akimune, T. Yamagata, M. Ohta, H. Toyokawa, K. Kudo, A. Uritani, Y. Shibata, Y.-W. Lui, H. Ohgaki

Physical Review D 68 巻 ( 7 ) 頁： 072001-1-072001-6 2003年10月

Characterization of a Thermal Neutron Field at the Heavy Water Neutron Irradiation Facility of the Kyoto University Reactor (II)

KURRI Progress Report 2002 頁： 129 2003年10月

New Position Sensitive Cryogenic Detector with Single Electron Transistor

J. Kawarabayashi, K. Aoki, T. Kadoi, K. Watanabe, A. Uritani, T. Iguchi

Nuclear Science Symposium Conference Record, 2003 IEEE 2 巻頁： 1355 - 1357 2003年10月

記述言語：英語

We proposed a new micro-calorimetric detector with four single electron transistor (SET) read-out circuits that aimed the real-time detector with spatial resolution of 100 nm. The new detector consists of two layers of the micro-calorimeters. The top layer had four SETs, which worked as thermometers to decide the photoelectron position by the difference of each SET's temperature caused by heat flow in the layer. We investigated the SET performance and the heat flow in the substrate at cryogenic temperature. From calculational results, the temperature resolution of 10 mK could be achieved with a pico-ammeter having 5.0 × 10-9S sensitivity. Also, the detector configuration achieving the 100 nm spatial and 8 μ second time resolution was successfully designed.

Characterization of a Thermal Neutron Field at the Heavy Water neutron Irradiation Facility of the Kyoto University Reactor

A. Uritani, C. H. Pyeon, K. Kudo, K. Kobayashi, T. Yoshimoto, Y. Sakurai, T. kobayashi and C. Mori

Proc. of 11th Inter. Conf. on Reactor Dosimetry 頁： 340-344 2003年8月

Development of Three-Dimensional Gamma Camera with Imaging Plates and Multi-Pinhole Collimators 査読有り

Naofumi Yamamura, Akira Uritani, Kenichi Watanabe, Jun Kawarabayashi and Tetsuo Iguchi

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment A505 巻 ( 1-2 ) 頁： 577-581 2003年6月

記述言語：英語掲載種別：研究論文（学術雑誌）

We have developed a novel multi-pinhole-type gamma camera for imaging low-energy gamma-ray emitters. The gamma camera consists of Imaging Plates (IPs) and multi-pinhole collimators made of a lead plate with many pinholes in lattice arrangement. The three-dimensional spatial distribution of a gamma-ray source is reconstructed by using a stereoscopic back-projection technique, where the directions of gamma-ray incidence are determined with the digitized two-dimensional images on the IPs and the configuration of the multi-pinhole collimators. The horizontal and vertical spatial resolutions for a point-like 57Co source evaluated with simulations are 1.5 and 2.5 mm, respectively.

Characterization of a Thermal Neutron Field at the Heavy Water Neutron Irradiation Facility of the Kyoto University Reactor

Japanese Nuclear data Committee, Progress Report INDC(JPN) 巻 ( 190/U ) 頁： 59-62 2003年3月

産総研シングルエンド・イオン加速器4MeV(ペレトロン4UH-HC)の現状

西島俊二、武田直人、小倉政彦、瓜谷章、工藤勝久

第15回タンデム加速器及びその周辺技術の研究会頁： 21-24 2003年3月

記述言語：日本語掲載種別：研究論文（学術雑誌）

設置以来使用してきた稼動心臓部でもあるチャージング用ペレット・チェーンのナイロン部品の劣化による事故などを懸念していたが、予算面から4年越しで少しずつ買い揃えて4本分のチェーンが揃ったので昨年5月に交換に至った。当所の加速器は直流ビーム電流150μA (H+ Beam)の大電流仕様であり、４本のチャージング・チェーンを持っている。　今回の報告は、チャージング・チェーン交換に伴うトラブル発生と加速器のエネルギー安定性について報告する。

通常光ファイバーを用いた強放射線分布センシング法の開発

河原林順、水野良治、中亮太郎、瓜谷章、渡辺賢一、井口哲夫、辻村憲雄

サイクル機構技報 ( 17 ) 頁： 97-107 2002年12月

記述言語：日本語

常のプラスチック光ファイバーにおいても放射線との相互作用で微弱シンチレーション光が発生することに着目し、これを用いることにより測定可能距離を大幅に延ばすとともに、その低検出効率を逆に活かして、より高フラックス下における放射線分布測定への適用可能性を検討した。その結果、これまでのシンチレーションファイバーを用いた場合に比べ、測定可能距離を約二桁のばすことできた。また、原子炉周辺や加速器、核融合実験装置環境等における放射線モニタリングへの適用の可能性を示した。また、ファイバー出力に対する分光学的片側読み出し手法を新規に考案し、その基本原理の有効性を実証した。

複眼式コリメータとイメージングプレートを用いた３次元ガンマカメラの開発

瓜谷章、山村直史、田渕明、渡辺賢一、井口哲夫

17 巻 ( 8 ) 頁： 71 2002年8月

高エネルギー加速器研究機構における黒鉛パイル熱中性子校正場の開発

米内俊祐、佐波俊哉、佐々木慎一、中村尚司、道川太一、瓜谷章

保健物理 37 巻 ( 2 ) 頁： 118-127 2002年6月

Characterization of a Thermal Neutron Field at the Heavy Water Neutron Irradiation Facility of the Kyoto University Reactor

Japanese Nuclear data Committee, Progress Report INDC(JPN) 巻 ( 189(U) ) 頁： 65-33 2002年3月

レーザー共鳴イオン化質量分析法を用いた極微量同位体分析における4重極質量分析器の適用性

服部和裕，渡辺賢一，河原林順，井口哲夫，瓜谷章

放射線 28 巻 ( 1 ) 頁： 55-60 2002年1月

Radiation Distribution Sensing with Normal Optical Fiber 査読有り

R. Naka, J. Kawarabayashi, K. Watanabe, A. Uritani, T. Iguchi, N. Hayashi, N. Kojima, T. Yoshida, J. Kaneko, H. Takeuchi, T. Kakuta

IEEE Transactions on Nuclear Science 48 巻 ( 6 ) 頁： 2348-2351 2001年12月

記述言語：英語掲載種別：研究論文（学術雑誌）

The purpose of this study is to develop a radiation distribution monitor using a normal plastic optical fiber. The monitor has a long operating length and can obtain continuous radiation distributions. A principle of the position sensing is based on a time-of-flight technique. The monitor is sensitive to beta rays or charged particles, gamma rays, and fast neutrons. The spatial resolutions for beta-rays ( 90Sr-90Y), gamma-rays (137Cs), and D-T neutrons are 30, 37, and 13 cm, respectively. The detection efficiencies for the beta-rays, gamma-rays, and D-T neutrons are 0.11%, 1.6×10 -5% and 1.2×10-4%, respectively. The effective attenuation length of the detection efficiency is 18 m. In this paper, we describe the basic characteristics of this monitor.

Development of Failed Fuel Detection and Location Technique Using Resonance Ionization Mass Spectrometry 査読有り

K. Watanabe, T. Iguchi, T. Ogita, A. Uritani and H. Harano

Journal of Nuclear Science and Technology 38 巻 ( 10 ) 頁： 844-849 2001年10月

Digital Waveform Analysis for ³He Ion Chamber 査読有り

J. Kawarabayashi, M. P. Mardiyanto, A. Uritani and T. Iguchi, Nagoya University; J. Kaneko and H. Takeuchi

IEEE Transactions on Nuclear Science 48 巻 ( 3 ) 頁： 527-529 2001年6月

記述言語：英語掲載種別：研究論文（学術雑誌）

Numerical analyzes on individual pulses from a cylindrical 3 He gas ionization chamber have been performed. A radial distribution of the electron ion pairs was successfully analyzed by a deconvolution technique combined with a digital waveform analysis. From the charge distribution, clear separation of events of the reactions of 3He(n,p)T and 3He(n,n)3He at the energy region of the 3He recoil edge was observed.

Energy Spectrum Improvement Based on Eucledian Distance with Digital-Analog Fusion Method 査読有り

M.P. Mardiyanto, A. Uritani, J. Kawarabayashi, and T. Iguchi

Journal of Nuclear Science and Technology 38 巻 ( 5 ) 頁： 301-305 2001年5月

記述言語：英語掲載種別：研究論文（学術雑誌）

The application of a `digital-analog hybrid signal processing system' combined with a Euclidian distance method is presented. The proposed method is used to improve gamma-ray energy spectrum characteristics of a CdZnTe semiconductor detector. A digital and an analog system are simultaneously applied to the detector output after passing through a preamplifier, where the digital system digitizes the signal pulse shape for the Euclidian distance determination, while the analog system measures the signal pulse height with a conventional analog method. In this paper, the digital and the analog data are combined to improve the energy spectrum characteristics; giving the increase of the photopeak area, the peak-to-valley ratio, and the photopeak sharpness.

Pulse Shape Analysis on Mixed Beta Particle and Gamma-ray Source Measures by CdZnTe Semiconductor Detector by Means of Digital-Analog Fusion Method 査読有り

M.P. Mardiyanto, A. Uritani, J. Kawarabayashi, T. Iguchi, and H. Sakai

Journal of Nuclear Science and Technology 38 巻 ( 5 ) 頁： 306-311 2001年5月

記述言語：英語掲載種別：研究論文（学術雑誌）

We present a study on pulse shapes of a CdZnTe semiconductor detector for beta particles and gamma-rays emitted by a 137Cs-90Sr mixed source. When beta and gamma radiations enter a semiconductor detector, two kinds of pulses are produced according to the type of radiations. The characteristics of the pulses are determined by their energy and depth of interaction. The energy deposited on the detector basically determines the pulse height and the depth of interaction affects the pulse shape. Because of the different characteristics of beta and gamma radiations, their pulse shapes are also different. The digital-analog hybrid signal processing method was applied to separation of the beta spectrum from the beta-gamma mixed one. The separation of beta spectrum was done based on a neural network algorithm, a leading edge area method, and a falling continuum tail value method. However, the perfect separation could not be obtained. The separation was also done by reconstructing the spectra on the basis of subtraction of gamma-ray component. The spectra of beta particles and gamma-rays from 137Cs-90Sr mixed source could be separated well by using the reconstruction method.

Pulse Shape Analysis Based on Similarity with Digital-Analog Fusion Method 査読有り

M.P. Mardiyanto, A. Uritani, H. Sakai, J. Kawarabayashi, and T. Iguchi

Nucl. Instr. and Methods A462 巻 ( 3 ) 頁： 405-410 2001年4月

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