Faculty Profiles - URITANI Akira

Papers - URITANI Akira

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Prompt gamma-ray imaging in realistic background conditions of a boron neutron capture therapy facility Open Access

Caracciolo, A; Mazzucconi, D; Ferri, T; Grisoni, L; Ghisio, F; Piroddi, M; Borghi, G; Carminati, M; Agosteo, S; Tsuchida, K; Nishitani, T; Ichikawa, Y; Uritani, A; Altieri, S; Protti, N; Fiorini, C

SCIENTIFIC REPORTS Vol. 15 ( 1 ) 2025.5

Effect of neutron beam properties on dose distributions in a water phantom for boron neutron capture therapy

Ishikawa, A; Tanaka, H; Nakamura, S; Kumada, H; Sakurai, Y; Watanabe, K; Yoshihashi, S; Tanagami, Y; Uritani, A; Kiyanagi, Y

JOURNAL OF RADIATION RESEARCH 2024.10

Estimation of nuclear properties in a deuteron–lithium target using JENDL/DEU-2020 for IFMIF and similar irradiation facilities Invited Reviewed

Takeo Nishitani, Sachiko Yoshihashi, Yuuki Tanagami, Shota Amano, Akira Uritani, Saerom Kwon, Keitaro Kondo, Kohki Kumagai, Kentaro Ochiai, Satoshi Sato

Fusion Engineering and Design Vol. 202 page： 114320 2024.5

First demonstration of a single-end readout position-sensitive optical fiber radiation sensor inside the Fukushima Daiichi Nuclear Power Station based on wavelength-resolving analysis

Terasaka, Y; Sato, Y; Uritani, A

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Vol. 1062 2024.5

Compton Imaging Using Pixelated TlBr Semiconductor Detector Invited Reviewed

Keitaro Hitomi, Motohiro Matsumura, Kenichi Watanabe, Shusuke Maruyama, Mitsuhiro Nogami, and Uritani Akira

Sensors and Materials Vol. 36 ( 1 ) page： 225 - 233 2024.3

Precise thermoluminescence glow curve analysis of BeO ceramic plates with slow heating rates

Sasaki, E; Sugioka, N; Chang, WS; Matsumoto, S; Negishi, T; Nagasaka, K; Yoshihashi, S; Uritani, A; Watanabe, K; Okada, G; Koba, Y; Shinsho, K

JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS Vol. 34 ( 31 ) 2023.11

A new application technique of a position-sensitive liquid light guide Cerenkov counter for the simultaneous position detection of 90Sr/90Y and 137Cs radioactivity

Terasaka, Y; Uritani, A

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Vol. 1049 2023.4

Neutron/y-ray discrimination based on the property and thickness controls of scintillators using Li glass and LiCAF (Ce) in a y-ray field

Kaburagi, M; Shimazoe, K; Terasaka, Y; Tomita, H; Yoshihashi, S; Yamazaki, A; Uritani, A; Takahashi, H

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Vol. 1046 2023.1

Measurements of γ-rays and neutrons in BNCT irradiation field using thermoluminescent phosphor

Shinsho, K; Oh, R; Tanaka, M; Sugioka, N; Tanaka, H; Wakabayashi, G; Takata, T; Chang, WS; Matsumoto, S; Okada, G; Sugawara, S; Sasaki, E; Watanabe, K; Koba, Y; Nagasaka, K; Yoshihashi, S; Uritani, A; Negishi, T

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 62 ( 1 ) 2023.1

Evaluation of heat removal performance of a sealed Li target for an accelerator-driven neutron source of Boron Neutron Capture Therapy at Nagoya University

Honda, S; Yoshihashi, S; Hamaji, Y; Shen, JJ; Tsuchida, K; Nishitani, T; Kiyanagi, Y; Tsurita, Y; Watanabe, K; Yamazaki, A; Uritani, A

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Vol. 1042 2022.11

Development of a Sealed Li target as an accelerator-driven neutron source for Boron neutron capture therapy at Nagoya University

Honda, S; Yoshihashi, S; Tomita, S; Tsuchida, K; Kiyanagi, Y; Tsurita, Y; Watanabe, K; Yamazaki, A; Uritani, A

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Vol. 1040 2022.10

光ファイバを用いた新方式片側読み出し型放射線分布測定法に関する基礎研究 Invited Reviewed

寺阪祐太、渡辺賢一、瓜谷章

放射線 Vol. 47 ( 3 ) page： 89 - 96 2022.10

γ-Ray measurements in boron neutron capture therapy using BeO ceramic thermoluminescence dosimeter

Tanaka, M; Oh, R; Sugioka, N; Tanaka, H; Takata, T; Wakabayashi, G; Sugawara, S; Watanabe, K; Uritani, A; Yoshihashi, S; Nagasaka, K; Okada, G; Negishi, T; Shinsho, K

JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS Vol. 33 ( 25 ) page： 20271 - 20279 2022.9

Neutronics Analyses of the Radiation Field at the Accelerator-Based Neutron Source of Nagoya University for the BNCT Study

Nishitani, T; Yoshihashi, S; Tanagami, Y; Tsuchida, K; Honda, S; Yamazaki, A; Watanabe, K; Kiyanagi, Y; Uritani, A

JOURNAL OF NUCLEAR ENGINEERING Vol. 3 ( 3 ) page： 222 - 232 2022.9

Evaluation of Induced Radioactivity Generated during LHD Deuterium Plasma Experiments*)

Yoshihashi, S; Yamada, H; Kobayashi, M; Nishitani, T; Yamazaki, A; Isobe, M; Ogawa, K; Uritani, A

PLASMA AND FUSION RESEARCH Vol. 17 2022.8

Theoretical and experimental estimation of the relative optically stimulated luminescence efficiency of an optical-fiber-based BaFBr:Eu detector for swift ions

Hirata, Y; Sato, T; Watanabe, K; Ogawa, T; Parisi, A; Uritani, A

JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY Vol. 59 ( 7 ) page： 915 - 924 2022.7

First demonstration of a novel single-end readout type position-sensitive optical fiber radiation sensor based on wavelength-resolved photon counting

Terasaka, Y; Watanabe, K; Uritani, A

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Vol. 1034 2022.7

Development of a simple calculation tool of dose distributions in a phantom for boron neutron capture therapy

Ishikawa, A; Watanabe, K; Yoshihashi, S; Sakurai, Y; Kumada, H; Tanaka, H; Uritani, A; Kiyanagi, Y

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 61 ( 7 ) 2022.7

Thermal Neutron Measurement Capability of a Single Crystal CVD Diamond Detector near the Reactor Core Region of UTR-KINKI

Kobayashi, MI; Yoshihashi, S; Yamanishi, H; Sangaroon, S; Ogawa, K; Isobe, M; Uritani, A; Osakabe, M

PLASMA AND FUSION RESEARCH Vol. 17 2022.6

Neutron yield calculation of p-Li thick target by using PHITS with JENDL-4.0/HE and ENDF/B-VII for BNCT application

Nishitani, T; Tanagami, Y; Yoshihashi, S; Tsuchida, K; Yamazaki, A; Uritani, A

JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY Vol. 59 ( 5 ) page： 605 - 613 2022.5

Neutron yield calculation of thin and thick d-D targets by using PHITS with frag data table

Nishitani, T; Yoshihashi, S; Ogawa, K; Miwa, M; Matsuyama, S; Uritani, A

JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY Vol. 59 ( 4 ) page： 534 - 541 2022.4

Strain distribution visualization of punched electrical steel sheets using neutron Bragg-edge transmission imaging

Sasada, S; Takahashi, Y; Takeuchi, K; Hiroi, K; Su, YH; Shinohara, T; Watanabe, K; Uritani, A

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 61 ( 4 ) 2022.4

Evaluation of the thermal neutron sensitivity, output linearity, and gamma-ray response of optical fiber-based neutron detectors using Li-glass scintillator

Ishikawa, A; Watanabe, K; Yamazaki, A; Yoshihashi, S; Imai, S; Masuda, A; Matsumoto, T; Tanaka, H; Sakurai, Y; Nogami, M; Hitomi, K; Uritani, A; Harano, H

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Vol. 1025 2022.2

High-spatial-resolution measurement of magnetization distribution using polarized neutron imaging

Sasada, S; Hiroi, K; Osanai, K; Shinohara, T; Watanabe, K; Uritani, A

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 60 ( 12 ) page： 126003-1 - 126003-6 2021.12

クルックス管実験に用いられる誘導コイルを利用した理科実験 Reviewed

森千鶴夫、瓜谷章、神谷均、佐合穣、臼井俊哉

日本放射線安全管理学会誌 Vol. 20 ( 2 ) page： 45 - 51 2021.12

Benchmark Calculation of d-Li Thick Target Neutron Yield by JENDL/DEU-2020 for IFMIF and Similar Facilities

Nishitani, T; Yoshihashi, S; Kumagai, K; Kondo, K; Uritani, A

PLASMA AND FUSION RESEARCH Vol. 16 2021.11

Feasibility Study of the One-Dimensional Radiation Distribution Sensing Method Using an Optical Fiber Sensor Based on Wavelength Spectrum Unfolding

Terasaka, Y; Watanabe, K; Uritani, A; Yamazaki, A; Sato, Y; Torii, T; Wakaida, I

JOURNAL OF NUCLEAR ENGINEERING AND RADIATION SCIENCE Vol. 7 ( 4 ) page： 042002-1 - 042002-7 2021.10

名古屋大学におけるBNCT用加速器中性子源の開発 Invited

土田一輝、瓜谷章、鬼柳善明、西谷建夫、吉橋幸子、渡辺賢一、山﨑淳、本田祥梧、辻義之、恒吉達也

Isotope News Vol. 777 page： 6 - 11 2021.10

Evaluation of a one-dimensional position-sensitive quartz optical fiber sensor based on the time-of-flight method for high radiation dose rate applications

Terasaka, Y; Watanabe, K; Uritani, A

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Vol. 996 2021.4

High heat removal technique for a lithium neutron generation target used for an accelerator-driven BNCT system

Yoshihashi, S; Tsuneyoshi, T; Tsuchida, K; Furuzawa, D; Honda, S; Watanabe, K; Yamazaki, A; Tsuji, Y; Hamaji, Y; Tokitani, M; Tamura, H; Sagara, A; Kiyanagi, Y; Uritani, A

JOURNAL OF INSTRUMENTATION Vol. 16 ( 4 ) page： P04016 2021.4

First experimental verification of the neutron field of Nagoya University Accelerator-driven neutron source for boron neutron capture therapy

Watanabe, K; Yoshihashi, S; Ishikawa, A; Honda, S; Yamazaki, A; Tsurita, Y; Uritani, A; Tsuchida, K; Kiyanagi, Y

APPLIED RADIATION AND ISOTOPES Vol. 168 2021.2

Thermal neutron measurement by single crystal CVD diamond detector applied with the pulse shape discrimination during deuterium plasma experiment in LHD Reviewed

Makoto Kobayashi, MaurizioAngelone, SachikoYoshihashi, KunihiroOgawa, MitsutakaIsobe, TakeoNishitani, SiriyapornSangaroon, ShujiKamio, YutakaFujiwara, TomomiTsubouchi, AkiraUritani, MinoruSakama, MasakiOsakabe, the LHD Experiment Group

Fusion Engineering and Design Vol. 161 page： 112063 2020.12

Language：Japanese Publishing type：Research paper (scientific journal)

The Pulse shape discrimination (PSD) technique for single crystal CVD diamond detector (SDD) was applied to
the real-time thermal neutron measurement during the 3rd campaign of Deuterium-Deuterium (D-D) plasma
experiment in the Large Helical Device (LHD). The PSD method is based upon the different shape of electrical
pulses produced in diamond by gamma-ray (triangular-shaped pulse) and energetic ions (rectangular-shaped
pulse), respectively. An improved PSD was developed which makes use of the full width at half maximum
(FWHM) and the full width at 2/3 of the peak height (FW2/3 PH). These two parameters reflect the difference in
the pulse shape produced by gamma-rays and energetic ions.
The performance of this improved PSD technique was first tested irradiating the SDD by gamma-rays from
60Co and alphas from 241Am radiation sources, respectively. Then, using a 6LiF thermal neutron converter, a
successful discrimination between gamma-rays and alpha particles and tritons generated by the 6Li(n,α)3H re-
action induced by neutrons from 252Cf spontaneous fission neutron source was achieved. Thanks to this PSD
processing technique, the thermal neutron detection efficiency increased about 1.7 times compared to previous
measurements performed without the PSD technique.
The real-time thermal neutron measurement by SDD with this enhanced PSD processing was also used during
D-D plasma discharges in the Large Helical Device (LHD). It was found that both the time integrated counts and
the time evolution count rate measured by the SDD reproduced well that of the fission chamber used as official
LHD neutron monitor. The capability of the SDD detector using the PSD technique of precise real-time thermal
neutron measurement in LHD was demonstrated.

DOI： 10.1016/j.fusengdes.2020.112063

Web of Science

Response evaluation of a compact and highly efficient neutron diffractometer for compact accelerator neutron sources Invited

Sho Imai, Kenichi Watanabe, Astushi Yamazaki, Sachiko Yoshihashi, Akira Uritani, Seiji Tasaki, Setsuo Satoh

Radiation Protection Vol. 40 ( 6 ) page： 540 - 544 2020.11

Observation of neutron emission anisotropy by neutron activation measurement in beam-injected LHD deuterium plasmas Reviewed

Sugiyama S., Nishitani T., Matsuura H., Isobe M., Ogawa K., Tanaka T., Yoshihashi S., Uritani A., Osakabe M.

NUCLEAR FUSION Vol. 60 ( 7 ) 2020.7

Development of Optical-fiber-based Neutron Detector Using Li-glass Scintillator for an Intense Neutron Field Reviewed

Akihisa Ishikawa, Atsushi Yamazaki, Kenichi Watanabe, Sachiko Yoshihashi, Akira Uritani, Yoshinori Sakurai, Hiroki Tanaka, Ryo Ogawara, Mitsuru Suda, and Tsuyoshi Hamano

Sensors and Materials Vol. 32 ( 4 ) page： 1489-1495 2020.4

Language：English Publishing type：Research paper (scientific journal)

The development of a neutron detector for real-time measurements in an intense neutron field is desired. We are developing a quartz optical-fiber-based neutron detector as a real-time neutron monitor. Thus far, Eu:LiCaAlF6 crystals and LiF/Eu:CaF2 eutectics were used as the scintillators of the quartz optical-fiber-based neutron detectors. These scintillators have high light yields, but relatively long decay time constants, which are limitation factors of the dynamic range of optical-fiber-based neutron detectors. In this paper, we applied a small Li-glass scintillator to a quartz optical-fiber-based neutron detector using an optical fiber with high numerical aperture (NA) and a UV-curable resin with high transmittance. The fabricated detector showed a clear peak corresponding to neutron events in the pulse height distribution. The radiation resistance was evaluated and no deterioration was observed up to 2×1012 n/cm2. The detector output linearity was confirmed up to 450 kcps, which was about ten times larger than that of the detector using the conventional Eu:LiCaAlF6 or LiF/Eu:CaF2 scintillator.

DOI： doi.org/10.18494/SAM.2020.2748

A comparison between simulation and experimental results for depth profile of Li-6 reaction rate in a water phantom of BNCT using a small Li-6-based scintillator neutron detector with an optical fiber Reviewed

Ishikawa Akihisa, Yamazaki Atsushi, Watanabe Kenichi, Yoshihashi Sachiko, Uritani Akira, Tsurita Yukio, Tsuchida Kazuki, Kiyanagi Yoshiaki

RADIATION MEASUREMENTS Vol. 133 2020.4

Design and Construction of an Imaging beamline at the Nagoya University Neutron Source Reviewed

Katsuya Hirota, Shogo Awano, Takuhiro Fujiie, Seiso Fukumura, Mayu Hishida, Go Ichikawa,, Sohei Imajo, Ikuya Itoh, Yoshihisa Iwashita, Masaaki Kitaguchi, Yoshiaki Kiyanagi, Yasutoshi Kuriyama, Koki Morikawa, Yu-dai Niinomi, Hirohiko M. Shimizu, Kazuki Tsuchida, Yusuke Tsuchikwa, Yukio Tsurita, Akira Uritani, Kenichi Watanabe, Yutaka Yamagata, Nana Yamamoto, Atsushi Yamazaki, Sachiko Yoshihashi and Tamaki Yoshioka

EPJ Web Conf. Vol. 231 page： 05002 2020.3

Language：English Publishing type：Research paper (scientific journal)

The Nagoya University Accelerator driven Neutron Source (NUANS) is constructed at the main campus of the Nagoya University. The electrostatic accelerator is used with the maximum proton energy and intensity of 2.8MeV, 15mA(42kW) respectively. Two neutron beamlines are designed at NUANS. The BL1 is dedicated to BNCT development. The BL2 is designed for research and development for neutron devices and neutron imaging. The neutrons used for the BL2 are generated by using the (p, n) reaction from a thin beryllium target. We constructed a compact target station for the BL2 and measured the neutron transmission image.

DOI： 10.1051/epjconf/202023105002

Basic study on a LiF-Eu:CaF₂ mixed powder neutron scintillator

Watanabe Kenichi, Mitsuboshi Natsumi, Ishikawa Akihisa, Yamazaki Atsushi, Yoshihashi Sachiko, Uritani Akira, Kawaguchi Noriaki, Yanagida Takayuki, Fukuda Kentaro

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Vol. 954 2020.2

Sensitivity and linearity of optical fiber-based neutron detectors using small Li-6-based scintillators

Ishikawa Akihisa, Yamazaki Atsushi, Watanabe Kenichi, Yoshihashi Sachiko, Uritani Akira, Fukuda Kentaro, Koike Akifumi, Ogawara Ryo, Suda Mitsuru, Hamano Tsuyoshi

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT Vol. 954 page： 161661-1 - 161661-5 2020.2

箔検電器によるクルックス管からのX 線の線量率測定 Reviewed

森千鶴夫，緒方良至，秋吉優史，臼井俊哉，村上浩介，羽澄大介，中村嘉行，渡辺賢一，瓜谷章，神谷均，佐合穣，宮川俊晴，田中隆一，掛布智久，森山正樹

Vol. 69 page： 1-12 2020.1

Language：Japanese Publishing type：Research paper (scientific journal)

高等学校などで使用されているクルックス管は，一般的に漏洩Ｘ線を発生している。Ｘ線の線量率の測定に，これらの学校が保有している箔検電器を使う方法を提案した。箔検電器の箔の開き角は電極に与えられた電位に依存して変化する。この電位はＸ線によって空気中に作られたイオンを集めて減少し箔は閉じて行く。しかし，空気中のイオン密度は周辺の電位や風，および箔検電器に荷電する電荷の正負の影響も受ける。正電荷を荷電した場合に箔が閉じる時間と負電荷を荷電した場合のそれとの幾何平均値をとることによって，電離箱で測定した線量率との間に再現性のある関係を得ることができた。この関係を校正線と呼ぶが，他の同様の市販の箔検電器にも適用できる。

DOI： 0.3769/radioisotopes.69.1

Development of Optical-fiber-based Neutron Detector Using Li glass Scintillator for an Intense Neutron Field

Ishikawa, A; Yamazaki, A; Watanabe, K; Yoshihashi, S; Uritani, A; Sakurai, Y; Tanaka, H; Ogawara, R; Suda, M; Hamano, T

SENSORS AND MATERIALS Vol. 32 ( 4 ) page： 1489 - 1495 2020

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

Tomoyo TANAKA, Makoto KOBAYASHI, Sachiko YOSHIHASHI, Akira URITANI, Kenichi WATANABE, Atsushi YAMAZAKI, Takeo NISHITANI, Kunihiro OGAWA and Mitsutaka ISOBE

Plasma and Fusion Research Vol. 14 page： 3405162-1 - 3405162-4 2019.11

Language：English Publishing type：Research paper (scientific journal)

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.14.340516

Pulsed Neutron Imaging Based Crystallographic Structure Study of a Japanese Sword made by Sukemasa in the Muromachi Period Reviewed

Kenichi Oikawa, Yoshiaki Kiyanagi, Hirotaka Sato, Kazuma Ohmae, Anh Hoang Pham, Kenichi Watanabe, Yoshihiro Matsumoto, Takenao Shinohara, Tetsuya Kai, Stefanus Harjo, Masato Ohnuma, k, Sigekazu Morito, Takuya Ohba, Akira Uritani, Masakazu Ito

Neutron Radiography WCNR-11 page： 207-213 2019.10

Crystallographic Structure Study of a Japanese Sword Masamitsu made in the 1969 using Pulsed Neutron Imaging Reviewed

Kazuma Ohmae, Yoshiaki Kiyanagi, Hirotaka Sato, Kenichi Oikawa, Anh Hoang Pham, Kenichi Watanabe, Yoshihiro Matsumoto, Takenao Shinohara, Tetsuya Kai, Stefanus Harjo, Masato Ohnuma, Shigekazu Morito, Takuya Ohba, Akira Uritani, M. Ito

Neutron Radiography WCNR-11 page： 227-232 2019.10

Comparative Study of Ancient and Modern Japanese Swords using Neutron Tomography Reviewed

Yoshihiro Matsumoto, Kenichi Watanabe, Kazuma Ohmae, Akira Uritani, Yoshiaki Kiyanagi, Hirotaka Sato, Masato Ohnuma, Anh Hoang Pham, Shigekazu Morito, Takuya Ohba, Kenichi Oikawa, Takenao Shinohara, Tetsuya Kai, Stefanus Harjo, Masakazu Ito

Neutron Radiography WCNR-11 page： 221-226 2019.10

Crystallographic Microstructure Study of a Japanese Sword made by Noritsuna in the Muromachi Period by Pulsed Neutron Bragg-Edge Transmission Imaging Reviewed

Hirotaka Sato, Yoshiaki Kiyanagi, Kenichi Oikawa, Kazuma Ohmae, Anh Hoang Pham, Kenichi Watanabe, Yoshihiro Matsumoto, Takenao Shinohara, Tetsuya Kai, Stefanus Harjo, Masato Ohnuma, Shigekazu Morito, Takuya Ohba, Akira Uritani, Masakazu Itoh

Neutron Radiography WCNR-11 page： 214-220 2019.10

Thermal neutron flux evaluation by a single crystal CVD diamond detector in LHD deuterium experiment Reviewed

Vol. 44 2019.9

Measurement of neutron spectrum using activation method in deuterium plasma experiment at LHD Reviewed

Tomoyo Tanak, Sachiko Yoshihashi, Makoto Kobayashi, Akira Uritani, Kenichi Watanabe, Atsushi Yamazaki, Takeo Nishitani, Kunihiro Ogawa, MitsutakaIsobe

Fusion Engineering and Design Vol. 146 page： 496 - 499 2019.9

Language：Japanese Publishing type：Research paper (scientific journal)

In the Large Helical Device (LHD) of the National Institute for Fusion Science, the experiments using deuterium plasma were performed from March 2017. Neutrons with the energy of 2.45 MeV are generated by d (d, n) 3He reactions. The evaluation of the neutron flux in the torus hall as well as the LHD vessel is very important for designing the decommissioning of the LHD in the future, and the radiation shielding for workers and components around LHD. In this study, we performed the activation experiments using multiple activation foils to obtain a neutron spectrum in the vacuum vessel of the LHD. The reaction rate of each activation foil was generally consistent with the calculation result by MCNP6. As a result of the unfolding with SAND-II code, we experimentally obtained the neutron spectrum in the vacuum vessel of the LHD for the first time.

DOI： 10.1016/j.fusengdes.2019.01.005

Web of Science

Thermal neutron flux evaluation by a single crystal CVD diamond detector in LHD deuterium experiment

Kobayashi, M; Ogawa, K; Isobe, M; Nishitani, T; Kamio, S; Fujiwara, Y; Tsubouchi, T; Yoshihashi, S; Uritani, A; Sakama, M; Osakabe, M

JOURNAL OF INSTRUMENTATION Vol. 14 ( 9 ) 2019.9

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

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 Vol. 14 page： 0 2019.6

Language：Japanese Publishing type：Research paper (scientific journal)

We developed a thermal neutron source for performance tests of boron agents for
Boron Neutron Capture Therapy (BNCT) at Neutron exposure Accelerator System for Biological
Effect Experiments (NASBEE) in National Institute of Radiological Sciences, Japan. The thermal
neutron flux at the experimental position was measured to be 2:18 108 ncm2s, the cadmium
ratio was 9:21, and gamma ray dose rate was 2:11 Gyh. The neutron dose rate was estimated to be
2:96 Gyh. These values indicate that the neutron source can be applicable for tests of boron agents
although application range is limited. An example of irradiation experiment is described.

DOI： 10.1088/1748-0221/14/06/T06010

Web of Science

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

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

Progress in Nuclear Science and Technology Vol. 6 page： 122-125 2019.2

Language：English Publishing type：Research paper (scientific journal)

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 Reviewed

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

Progress in Nuclear Science and Technology Vol. 6 page： 238-242 2019.2

Language：English Publishing type：Research paper (scientific journal)

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

Development of wide one-dimensional X-ray line sensor in backscatter X-ray imaging system for infrastructure inspection Reviewed

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

Progress in Nuclear Science and Technology Vol. 6 page： 208-211 2019.2

Language：English Publishing type：Research paper (scientific journal)

We fabricated a wide one-dimensional X-ray line sensor in backscatter X-ray imaging system. The length and width of the sensitive area of our line sensor is 200 mm and 50 mm, respectively. By using fan-beam X-rays and scanning in the perpendicular direction to the fan-beam plane, two-dimensional backscatter X-ray images can be obtained. In basic experiments, we confirmed that an iron rod placed at the depth of, at least, 9 cm in a concrete brock can be seen by combining our line sensor and C-band linac X-ray generator.

DOI： 10.15669/pnst.6.208

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

Tanaka, T; Kobayashi, M; Yoshihashi, S; Uritani, A; Watanabe, K; Yamazaki, A; Nishitani, T; Ogawa, K; Isobe, M

PLASMA AND FUSION RESEARCH Vol. 14 2019

Development of a neutron source for imaging at the electron linac facility in Kyoto University Research Reactor Institute Reviewed

Yoshiyuki Takahashi, Yoshiaki Kiyanagi, Kenichi Watanabe, Akira Uritani, Tadafumi Sano, Junichi Hori, Ken Nakajima

Physica B: Condensed Matter Vol. 551 page： 488-491 2018.12

Language：English Publishing type：Research paper (scientific journal)

The Kyoto University electron linac, KURRI-LINAC, has been used for executing a project to develop methodology for the integrity evaluation of nuclear fuels, named the N-DeMAIN (Development of Non-Destructive Methods Adapted for Integrity test of Next generation nuclear fuels) project in Japan. As a non-destructive method, the neutron resonance transmission analysis was adopted for the identification and the quantification of nuclide in the fuels. Furthermore, determination of temperature distribution in the fuels based on Doppler broadening was also planned as well as traditional transmission imaging.
A target-moderator-reflector system (TMRS) and a beam collimator system has been redesigned to obtain the highest intensity with the use of simulation calculation. The neutron beam line is placed at an angle of 135° with respect to the electron beam line. Optimal arrangement of the target and the moderator was investigated. After then, collimator design was performed, and a collimator system to shape the neutron and γ ray beams was designed. Test experiments were performed by using this system.
Here, we explain the results of design study of the TMRS and the collimator, and the test experiments.

DOI： doi.org/10.1016/j.physb.2018.06.009

Development of a neutron source for imaging at the electron linac facility in Kyoto University Research Reactor Institute

Takahashi, Y; Kiyanagi, Y; Watanabe, K; Uritani, A; Sano, T; Hori, J; Nakajima, K

PHYSICA B-CONDENSED MATTER Vol. 551 page： 488 - 491 2018.12

Development of x-ray backscatter imaging system for inspection of concrete structure Invited

Vol. 23 ( 11 ) page： 13-18 2018.11

Design of Beam Shaping Assembly for an Accelerator-driven BNCT System in Nagoya University Reviewed

Akira URITANI, Yosuke MENJO, Kenichi WATANABE, Atsushi YAMAZAKI, Yoshiaki KIYANAGI and Kazuki TSUCHIDA

JPS Conf. Proc. Vol. 22 page： 011002-1 - 011002-7 2018.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

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 nuclear reaction produces neutrons. Since the generated neutrons have considerably high energy, up to one MeV, it is necessary to lower the neutron energy to an epithermal 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 BSA consists of a MgF2 moderator, a lead reflector, a radiation shield and a neutron collimator. The PHITS (Ver.2.66) code has been used to simulate the neutron transport in the BSA. This paper mainly describes two issues. One is the optimization of the shape of the BSA, mainly the moderator, and the other is the dependence of the simulation results on the nuclear data libraries, JENDL-4.0 and ENDF/B-VII.1.

DOI： 10.7566/JPSCP.22.011002

Construction of the 2nd Beamline of Nagoya University Accelerator-driven Neutron Source (NUANS) Reviewed

Yusuke Tsuchikawa, Keisuke Abo, Daiki Furuzawa, Katsuya Hirota, Go Ichikawa, Sohei Imajo, Ikuya Ito, Yoshihisa Iwashita, Masaaki Kitaguchi, Yoshiaki Kiyanagi, Yasuhiko Miwata, Kazuya Sato, Hirohiko M. Shimizu, Hayato Takeshita, Kazuki Tsuchida, Yukio Tsurita, Akira Uritani, Kenichi Watanabe, Yutaka Yamagata, Atsushi Yamazaki, and Sachiko Yoshihashi

JPS Conf. Proc. Vol. 22 page： 011024-1 - 011024-4 2018.11

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

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

JPS Conf. Proc. Vol. 22 page： 011003-1 - 011002-7 2018.11

Development of One-Dimensional Position-Sensitive Neutron Detector Using TRUST Eu:LiCAF Scintillator Reviewed

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

JPS Conf. Proc. Vol. 22 page： 011020-1 - 011002-8 2018.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

We developed a one-dimensional position-sensitive neutron detector using 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 WLSFs optically divided to distinguish the scintillation position. We experimentally compared the position sensitivities of the optically divided WLSF type detector and a conventional one using light attenuation in the WLSFs. We concluded that the proposed detector had higher spatial resolution than that of the conventional one. Additionally, we fabricated a prototype version of the optically divided WLSF type detector. We determined the prototype detector had a relative spatial resolution of approximately 20 %.

DOI： 10.7566/JPSCP.22.011020

Neutron Diagnostics in the Large Helical Device Reviewed

Mitsutaka Isobe, Kunihiro Ogawa, Takeo Nishitani, Hitoshi Miyake, Takashi Kobuchi, Neng Pu, Hoiroki Kawase, Eiji Takada, Tomoyo Tanaka, Siyuan Li, Sachiko Yoshihashi, Akira Uritani, Jungmin Jo, Sadayoshi Murakami, Masaki Osakabe

IEEE Transactions on Plasma Science Vol. 46 ( 6 ) page： 2050 - 2058 2018.6

Language：English Publishing type：Research paper (scientific journal)

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 3.3×10¹⁵(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

Web of Science

二種類の光刺激蛍光体と光ファイバーを用いたハイブリッド小型線量計による炭素線照射時に発生する消光現象の補正法の検討

平田悠歩、山﨑淳、渡辺賢一、吉橋幸子、瓜谷章、古場裕介、松藤成弘、柳田健之、福田健太郎

放射線 Vol. 43 ( 4 ) page： 139-142 2018.1

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

N. Pu, T. Nishitani, M. Isobe, K. Ogawa, H. Kawase, T. Tanaka, S. Y. Li, S. Yoshihashi and A. Uritani

Review of Scientific Instruments Vol. 88 ( 11 ) page： 113302 2017.11

Language：English Publishing type：Research paper (scientific journal)

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 foil-stacked with total mass of approximately 18 g were prepared. Each capsule was irradiated over 15 hours 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 by three-dimensional neutron transport calculations using the MCNP 6 code. The activation response coefficients for 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.

Correction of quenching effect of a small size OSL dosimeter using Eu:BaFBr and Ce:CaF₂

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

RADIATION MEASUREMENTS Vol. 106 page： 246 - 251 2017.11

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

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

REVIEW OF SCIENTIFIC INSTRUMENTS Vol. 88 ( 11 ) 2017.11

名古屋大学における加速器BNCT用システムの開発― Li封入型ターゲットの除熱方法の検討― Invited

古澤大貴、瓜谷章、渡辺賢一、吉橋幸子、山崎淳、鬼柳善明、土田一輝、辻義之、恒吉達矢、浜地志憲、時谷政行、田村仁、相良明男

Vol. 4 page： 22-23 2017.9

Correction of quenching effect of a small size OSL dosimeter using Eu:BaFBr and Ce:CaF₂ Reviewed

Yuho Hirata, KenichiWatanabe, AkiraUritani, AtsushiYamazaki, Yusuke Koba, Naruhiro Matsufuji, TakayukiYanagida, Kentaro Fukuda

Radiation Measurements Vol. 106 page： 246-251 2017.4

Language：English Publishing type：Research paper (scientific journal)

To accurately estimate an actual dose during radiotherapy treatment, dosimeters are required to be inserted into the affected region in a patient's body. Therefore, we are developing a small size dosimeter consisting of optical fibers and optically stimulated luminescence (OSL) elements. We fabricated two types of small size dosimeters using Eu:BaFBr and Ce:CaF₂. We measured the Bragg peak of high energy carbon ions in a water equivalent material. OSL materials showed the quenching effect when irradiated by high linear energy transfer (LET) particles. The sensitivity of Eu:BaFBr and Ce:CaF₂ monotonically decreased with different coefficients. The ratio of the signal intensity of these two OSL materials can uniquely determine the sensitivity of each OSL material. We corrected the quenching effect of the OSL dosimeters in the spread out Bragg peak with this relationship.

Particle Dependence of Quenching Effect in an Optical-Fiber-Type Optically Stimulated Luminescence Dosimeter

Hirata Yuho, Watanabe Kenichi, Yoshihashi Sachiko, Uritani Akira, Koba Yusuke, Naruhiro Matsufuj I, Yanagida Takayuki, Toshito Toshiyuki, Fukuda Kentaro

SENSORS AND MATERIALS Vol. 29 ( 10 ) page： 1455 - 1464 2017

Upgrade of neutron energy spectrometer with single multilayer Bonner sphere using onion-like structure Reviewed

T. Mizukoshi, K. Watanabe, A. Yamazaki, A. Uritani, T. Iguchi, T. Ogata and T. Muramatsu

Journal of Radiation Protection and Research Vol. 41 ( 3 ) page： 185-190 2016.9

Quenching Effect in an Optical Fiber Type Small Size Dosimeter Irradiated with 290 MeV·u^-1 Carbon Ions Reviewed

Vol. 41 ( 3 ) page： 222-228 2016.9

Recent Progress in the Fusion Neutronics 7. Status of the Fusion Neutronics in the Domestic Fusion Facilities

SUKEGAWA Atsuhiko, URITANI Akira, NISHIMURA Kiyohiko and NISHITANI Takeo

JOURNAL OF PLASMA AND FUSION RESEARCH Vol. 92 ( 4 ) page： 282-285 2016.4

Basic study on response of a small size dosimeter using optical fiber and Ce:CaF₂ OSL element

Hirata, Y.; Watanabe, K.; Yamazaki, A.; Uritani, A.; Koba, Y.; Matsufuji, N.; Yanagida, T.; Fukuda, K.

Vol. 41 ( 3 ) page： 157-161 2016

Language：Japanese Publishing type：Research paper (scientific journal)

We fabricated a small size optical fiber type dosimeter system using Ce:CaF₂ OSL element. We evaluated basic response of fabricated dosimeter to radiations of X-ray and high-energy carbon ions. When irradiating X-ray, good linearity can be confirmed. With increasing linear energy transfer (LET) of carbon ions, luminescence efficiency of Ce:CaF₂ decreases. Compared with the conventional small dosimeter using Eu:BaFBr OSL element, Ce:CaF₂ shows a small deterioration in the luminescence efficiency.

Study on neutron energy spectrometer with onion-like single bonner sphere using TRUST Eu:LiCAF scintillator

Mizukoshi, T.; Watanabe, K.; Yamazaki, A.; Uritani, A.; Iguchi, T.; Ogata, T.; Muramatsu, T.

Vol. 41 ( 3 ) page： 151-155 2016

Language：Japanese Publishing type：Research paper (scientific journal)

We fabricated the prototype of a single sphere neutron spectrometer with five sensitive layers using the Transparent FUbber SheeT Eu:LiCaAlF₆ (TRUST Eu:LiCAF) scintillator and the wavelength-shifting fibers (WLSFs). We confirmed that the fabricated detector shows a clear neutron peak and can discriminate neutron and gamma-ray events in signal pulse height spectra. We additionally compared the neutron sensitivity between the new TRUST Eu:LiCAF type and the previous LiF-ZnS mixed powder type. The sensitivity of the new one is 40 times higher than that of the previous one.

Study on Effects of Gamma-Ray Irradiation on TlBr Semiconductor Detectors Reviewed

Motohiro Matsumura, Kenichi Watanabe, Atsushi Yamazaki, Akira Uritani, Norihisa Kimura, Nobumichi Nagano, and Keitaro Hitomi

JPS Conf. Proc. Vol. 11 page： 030005-1 - 030005-5 2016

Wavelength-shifting fiber signal readout from Transparent RUbber SheeT (TRUST) type LiCaAlF₆ neutron scintillator Reviewed

Kenichi Watanabe, Takuya Yamazaki, Dai Sugimoto, Atsushi Yamazaki, Akira Uritani, Tetsuo Iguchi, Kentaro Fukuda, Sumito Ishidu, Takayuki Yanagida, Yutaka Fujimoto

Nuclear Instruments and Methods A Vol. 784 page： 260-263 2015.6

Language：English Publishing type：Research paper (scientific journal)

As an alternative to the standard 3He neutron detector, we are developing the Transparent RUbber SheeT type (TRUST)Eu doped LiCaAlF6 (Eu:LiCAF)scintillator. This type of neutron scintillator can easily be fabricated as a large area sheet. In order to take advantage of a large area detector, we try to read out scintillation photons using a wavelength-shifting fiber (WLSF) from a TRUSTEu:LiCAF scintillator. The TRUST Eu:LiCAF scintillator with the size of 50x50x5 mm3 was mounted on the WLSF plate and the end of the WLSFs was connected with a PMT. In order to reject high pulse height events induced in the WLSFs, we applied the pulse shape discrimination technique. The gamma-ray intrinsic and neutron
absolute detection efficiency is evaluated to be 8.8x10^7 and 9x103 cps/ng Cf(2m) for the TRUSTEu:
LiCAF scintillator with the size of 50x50x5 mm^3.

Development of X-ray backscatter system to inspect the inner structure of concrete Invited

Hiroyuki Toyokawa, Shinichi Mandai, Akira Uritani, Kenichi Watanabe

page： 0 2015.5

Language：Japanese

There are more than 700 thousand road bridges, whose lengths are longer than 2 m. Sixteen percent of them were built more than 50 years ago, and their fraction will increase to 40% and 65%, in next 10 years and 20 years, respectively. The maintenance, inspection and repair of them are managed mainly by a local government, which the infrastructures are located. However, the management of the infrastructure is becoming more difficult for the local governments, because of the lack of a financial resource, human resource, and technical knowledge. In Japan, the deterioration of the infrastructures by the sea wind and the salt is serious especially for the roadbed and the reinforced concrete due to the corrosion. Nondestructive inspection methods, which are currently being applied on-site are not enough to measure the degree of damage of concretes, quantitatively. So, a novel method for nondestructive inspection of inner structure of concrete with radiation instrumentation and electron accelerator, which uses X-ray backscatter is being developed. The X-ray backscatter system, which has advantages in highly precise image and one-sided accessibility in inspection, is developed for use in inspecting roadbed and bridge, as a compact and light-weight system. Nondestructive inspection by visualization, using a high resolution X-ray backscatter image for reinforcement bar and a pot-hole inside concrete structure will be possible.

Development of an optical fiber type detector using a Eu:LiCaAlF₆ scintillator for neutron monitoring in boron neutron capture therapy Reviewed

Kenichi Watanabe, Yuya Kawabata, Atsushi Yamazaki, Akira Uritani, Tetsuo Iguchi, Kentaro Fukuda, Takayuki Yanagida

Nuclear Instruments and Methods in Physics Research A Vol. A802 page： 1-4 2015

Portable Neutron Detector Using Ce:LiCaAlF₆ Scintillator Reviewed

Kenichi Watanabe, Takayuki Yanagida, Kentaro Fukuda, Akifumi Koike, Toru Aoki and Akira Uritani

SENSORS AND MATERIALS Vol. 27 ( 3 ) page： 269-275 2015

Language：English Publishing type：Research paper (scientific journal)

We fabricated a prototype portable neutron detector using a Ce:LiCaAlF₆ (Ce:LiCAF) scintillator and evaluated its basic performance. The weight of the fabricated detector including the battery is 800 g, significantly less than that of the conventional portable neutron detector, which weighs more than 5 kg. The neutron sensitivity of the fabricated detector is evaluated to be 2.3 cps/(mu Sv/h), comparable to that of the conventional detector. The gamma-ray intrinsic detection efficiency is evaluated to be less than 10(-6). The gamma-ray sensitivity is sufficiently low under ordinary circumstances. The expected count rate of the error counting due to the pile-up effect of gamma-ray-induced events is confirmed to be less than the background count rate for an incident gamma-ray rate of less than 10(4) gammas/s.

Study on fast luminescence component induced by gamma-rays in Ce doped LiCaAlF₆ scintillators Reviewed

Kenichi Watanabe, Yoshiyuki Kondo, Atsushi Yamazaki, Akira Uritani, Tetsuo Iguchi, Noriaki Kawaguchi, Kentaro Fukuda, Sumito Ishizu, Takayuki Yanagida, Yutaka Fujimoto, Akira Yoshikawa

Radiation Measurements Vol. 71 page： 158-161 2014.12

Scintillation properties of composite ceramic YAG and its capability on pulse shape descrimination Reviewed

Takayuki Yanagida, Kenichi Watanabe, Yutaka Fujimoto, Akira Uritani, Hideki Yagi and Takagimi Yanagitani

JOURNAL OF THE CERAMIC SOCIETY OF JAPAN ( 122 ) page： 1016-1019 2014.12

Language：English Publishing type：Research paper (scientific journal)

Transparent ceramic composite of non-doped and Ce-doped YAG was prepared by Konoshima Chemical with the vacuum sintering technique and investigated on pulse shape discrimination capability for functional collimator. Scintillation responses such as X-ray induced radioluminescence and decay time profiles of non-doped and Ce-doped YAG were evaluated. Pulse shape discrimination capability of the composite ceramic was evaluated by Cs-137 662 keV gamma-ray irradiation. As a result, clear separation of gamma-ray events at non-doped or Ce-doped YAG layers was observed in two dimensional histogram by using signal processing with two different shaping times. (C) 2014 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.122.1016

Study on in situ calibration for neutron flux monitor in the Large Helical Device based on Monte Carlo calculations Reviewed

Y. Nakano, A. Yamazaki, K. Watanabe, A. Uritani, K. Ogawa, M. Isobe

Rev. Sci. Instrum. Vol. 85 ( 11 ) page： 11E116-11E116-3 2014.11

Language：English Publishing type：Research paper (scientific journal)

Neutron monitoring is important to manage safety of fusion experiment facilities because neutrons are generated in fusion reactions. Monte Carlo simulations play an important role in evaluating the influence of neutron scattering from various structures and correcting differences between deuterium plasma experiments and in situ calibration experiments. We evaluated these influences based on differences between the both experiments at Large Helical Device using Monte Carlo simulation code MCNP5. A difference between the both experiments in absolute detection efficiency of the fission chamber between O-ports is estimated to be the biggest of all monitors. We additionally evaluated correction coefficients for some neutron monitors.

DOI： 10.1063/1.4891049

Progress in development of the neutron profile monitor for the large helical devicea Reviewed

K. Ogawa, M. Isobe, E. Takada, Y. Uchida, K. Ochiai, H. Tomita, A. Uritani, T. Kobuchi and Y. Takeiri

Rev. Sci. Instrum. Vol. 85 ( 11 ) page： 11E110-11E110-3 2014.11

Language：English Publishing type：Research paper (scientific journal)

The neutron profile monitor stably operated at a high-count-rate for deuterium operations in the Large Helical Device has been developed to enhance the research on the fast-ion confinement. It is composed of a multichannel collimator, scintillation-detectors, and a field programmable gate array circuit. The entire neutron detector system was tested using an accelerator-based neutron generator. This system stably acquires the pulse data without any data loss at high-count-rate conditions up to 8 × 105 counts per second.

DOI： 10.1063/1.4890399

Wide dynamic range neutron flux monitor having fast time response for the Large Helical Device) Reviewed

M. Isobe, K. Ogawa, H. Miyake, H. Hayashi, T. Kobuchi, Y. Nakano, K. Watanabe, A. Uritani, T. Misawa, T. Nishitani, M. Tomitaka, T. Kumagai, Y. Mashiyama, D. Ito, S. Kono, M. Yamauchi and Y. Takeiri

Rev. Sci. Instrum. Vol. 85 ( 11 ) page： 11E114-11E114-4 2014.11

Language：English Publishing type：Research paper (scientific journal)

A fast time response, wide dynamic range neutron flux monitor has been developed toward the LHD deuterium operation by using leading-edge signal processing technologies providing maximum counting rate up to ~5 x 10^9 counts/s. Because a maximum total neutron emission rate over 1 x 10^16 n/s is predicted in neutral beam-heated LHD plasmas, fast response and wide dynamic range capabilities of the system are essential. Preliminary tests have demonstrated successful performance as a wide dynamic range monitor along the design.

DOI： 10.1063/1.4891049

Study on In-Situ Calibration for Neutron Monitor in the Helical Type Fusion Experimental Device Based on Monte Carlo Calculations Reviewed

Y. Nakano, A. Yamazaki, K. Watanabe, A. Uritani, K. Ogawa, M. Isobe

Plasma and Fusion Research Vol. 9 page： 3405141-1 - 3405141-4 2014.10

Language：English Publishing type：Research paper (scientific journal)

Monte Carlo simulations in design of neutron monitors for fusion experimental devices play an important role
to evaluate the influence of scattering from various structures and to correct differences between neutron energies from calibration source and fusion plasma. We have developed an automated input file generation code based on finely segmented helical coil approximation. In this paper, we study the optimal number of divisions of segmented geometry from viewpoints of simulation precision and required calculation time. We conclude that results with more than 360 divisions saturate into the result with fully fine simulation. And we evaluate influence of neutron scattering from a miniature train, a railroad and supporting structures used in in-situ calibration experiments at LHD.

Study on Neutron detector using transparent rubber sheet with dispersed small pieces of LiCaAlF₆ Scintillator Invited

Vol. 40 ( 1 ) page： 67-70 2014.3

巻頭言　福島復興に向けた放射線計測研究者への期待

瓜谷章

放射線 Vol. 39 ( 4 ) page： 151 2014.2

Neutron TOF Experiments Using Transparent Rubber Sheet Type Neutron Detector with Dispersed Small Pieces of LiCaAlF₆ Scintillator Reviewed

Dai Sugimoto, Kenichi Watanabe, Katsuya Hirota, Atushi Yamazaki, Akira Uritani, Tetsuo Iguchi, Kentaro Fukuda, Sumito Ishidu, Noriaki Kawaguchi, Takayuki Yanagida, Yutaka Fujimoto, Akira Yoshikawa, Hiroyuki Hasemi, Kouichi Kino, Yoshiaki Kiyanagi

Physics Procedia Vol. 60 page： 349-355 2014

Scintillation Properties of LiF-SrF₂ and LiF-CaF₂ Eutectic Reviewed

Noriaki Kawaguchi, Takayuki Yanagida, Yutaka Fujimoto, Yuki Furuya, Yoshisuke Futami, Akihiro Yamaji, Kenichi Watanabe, Atsushi Yamazaki, Akira Uritani, Shinji Kajimoto, Hiroshi Fukumura, Shunsuke Kurosawa, Yuui Yokota, Jan Pejchal, Akira Yoshikawa

Journal of Luminescence Vol. 144 page： 212-216 2013.12

3. Radiation Measurement in Fusion Facility 3.3 Fundamentals and Applications of Neutron Measurement Invited

Akira URITANI

J. Plasma Fusion Research Vol. 89 ( 10 ) page： 686-690 2013.10

Neutron Detection with LiCaAlF₆ Scintillator Doped with 3d-transition Metal Reviewed

Radiation Measurements Vol. 55 page： 128-131 2013.8

Language：English Publishing type：Research paper (scientific journal)

We have developed a novel micro-size dosimeter using an optical fiber probe coupled with a photostimulable storage phosphor, such as BaFBr:Eu2+. Our micro-size dosimeter is based on the concept in which the radiation dose response is temporally compressed by using integrating-type dosimeter elements, such as a photostimulable storage phosphor, and the signal-to-noise ratio is improved to downsize the dosimeter probe. We fabricate the prototype dosimeter probe which has the detectable volume of 100 mm thick and 400 mm diameter and the outer diameter of 900 mm. The lower limit of detectable dose, which is defined as three times the noise level, is evaluated to be 0.9 mGy. This value is much smaller than the typical irradiation dose (a few Gy per treatment) in the radiotherapy. We, therefore, conclude that the proposed micro-size dosimeter can be a promising candidate of in-vivo and on-line dose monitor in the
radiotherapy.

Development of a Micro-Size Dosimeter Using an Optical Fiber Probe Based on Photostimulable Phosphorescence Reviewed

Kenichi Watanabe, Atsushi Yamazaki, Kotaro Nakahashi, Hidefumi Miyamae, Akira Uritani, Eiji Ariga

Radiation Measurements Vol. 55 page： 64-67 2013.8

Language：English Publishing type：Research paper (scientific journal)

Origin of Fast Scintillation Components of LiCaAlF₆ Crystals Reviewed

Masanori Koshimizu, Takayuki Yanagida, Yutaka Fujimoto, Atsushi Yamazaki, Kenichi Watanabe, Akira Uritani, Kentaro Fukuda, Noriaki Kawaguchi, Shunji Kishimoto, and Keisuke Asai

Applied Physics Express Vol. 6 page： 062061-1 - 062061-3 2013.5

Language：English Publishing type：Research paper (scientific journal)

The origin of the fast scintillation component of Ce-doped LiCaAlF6 crystal excited by gamma ray irradiation was studied with X-ray and vacuum
ultraviolet (VUV) irradiation. A fast luminescence component was observed under VUV irradiation and was ascribed to luminescence at defects in
the host matrix on the basis of VUV spectroscopy. No fast scintillation component was observed in the scintillation time profile under X-ray
irradiation. The fast scintillation component under gamma ray irradiation can be concluded to be the result of Cherenkov radiation from energetic
secondary electrons.

Ce-doped LiF-SrF₂ Eutectic Scintillators for Thermal Neutron Detection Produced at Different Solidification Rates Reviewed

Takayuki Yanagida, Yutaka Fujimoto, Kentaro Fukuda, Noriaki Kawaguchi, Kenichi Watanabe, Atsushi Yamazaki, Akira Uritani, Valery Chani

Optical Materials Vol. 35 ( 7 ) page： 1449-1454 2013.5

Study on Background Gamma-Ray Reduction Using a Compton Backscattering Coincidence Technique

Takashi Takagi, Kenichi Watanabe, Atsushi Yamazaki, and Akira Uritani

IEEE TRANSACTIONS ON NUCLEAR SCIENCE Vol. 60 ( 2 ) page： 550-554 2013.4

Temperature Dependence of Neutron-Gamma Discrimination Based on Pulse Shape Discrimination Technique in a Ce:LiCaAlF₆ Scintillator

Kenichi Watanabe, Yoshiyuki Kondo, Atsushi Yamazaki, Akira Uritani, Tetsuo Iguchi, Noriaki Kawaguchi, Kentaro Fukuda, Sumito Ishidu, Takayuki Yanagida, Yutaka Fujimoto, and Akira Yoshikawa

IEEE TRANSACTIONS ON NUCLEAR SCIENCE Vol. 60 ( 2 ) page： 959-962 2013.4

Two-dimensional Differential Calibration Method for a Neutron Dosimeter Using a Thermal Neutron Beam Reviewed

Matsumoto, Tetsuro; Harano, Hideki; Masuda, Akihiko; Nishiyama, Jun; Matsue, Hideaki; Uritani, Akira; Nunomiya, Tomoya

Vol. 155 ( 4 ) page： 505-511 2013.3

Eu-doped ⁶LiF-SrF₂ Eutectic Scintillators for Neutron Detection Reviewed

Takayuki Yanagida, Kentaro Fukuda, Yutaka Fujimoto, Noriaki Kawaguchi, Shunsuke Kurosawa, Atsushi Yamazaki, Kenichi Watanabe, Yoshisuke Futami, Yuui Yokota, Jan Pejchal, Akira Yoshikawa, Akira Uritani, Tetsuo Iguchi

Vol. 34 ( 5 ) page： 868-871 2012.3

Ultrafast Transparent Ceramic Scintillators Using the Yb³⁺ Charge Transfer Luminescence in RE₂O₃ Host Reviewed

Takayuki Yanagida, Yutaka Fujimoto, Shunsuke Kurosawa, Kenichi Watanabe, Hideki Yagi, Takagimi Yanagitani, Vitezslav Jary, Yoshisuke Futami, Yuui Yokota, Akira Yoshikawa, Akira Uritani, Tetsuo Iguchi, and Martin Nikl

Applied Physics Express 4 (2011) 126402 Vol. 4 page： 126402-126404 2011.12

Language：English Publishing type：Research paper (scientific journal)

We report a new discovery of Yb3+-doped ultrafast scintillators based on the Yb3+ charge transfer luminescence. Transparent ceramic Yb3+-doped Y2O3, Sc2O3, Lu2O3, and Yb2O3 were prepared by sintering. When irradiated by γ- and X-rays, they showed a well detectable photoabsorption peak in the pulse height spectra and ultrafast scintillation decay dominated by the decay time of about 1 ns. For the first time, the Yb3+-doped oxide materials show detectable scintillation in the pulse height measurement at room temperature with ultrafast scintillation decay.

Feasibility Study on a Micro-Size Dosimeter Using an Optical Fiber Probe Based on a Photostimulable Phosphorescence Reviewed

Kotaro Nakahashi, Kenichi Watanabe, Akira Uritani, Atsushi Yamazaki, Eiji Ariga

Radiation Measurement Vol. 46 ( 12 ) page： 1547-1550 2011.12

Language：English Publishing type：Research paper (scientific journal)

We propose a novel micro-size dosimeter using an optical fiber probe based on the PSL from the BaFBr:Eu2þ. Through basic experiments using the prototype dosimeter, the feasibility of the proposed dose monitoring method has been confirmed.We confirmthat increasing the stimulus laser poweris effective to improve the signal to noise ratio. The lower limit of detectable dose of the prototype dosimeter probe having sensitive region with the diameter of 200 mm is preliminarily estimated to be 11 mGy for a Co-60 gamma-rays. This value is much smaller than the typical irradiation dose (a few Gy per treatment) in the radiotherapy.We can measure the dose in a few hundred subdivisions during a treatment. We, therefore, conclude that the
proposed micro-size dosimeter can be a promising candidate of in-vivo and on-line dose monitor in the
radiotherapy.

Development of Novel Rare Earth Doped Fluoride and Oxide Scintillators for Two-Dimensional Imaging Reviewed

Vol. 29 ( 12 ) page： 1178-1182 2011.12

Language：English Publishing type：Research paper (scientific journal)

Two topics were focused. The first one was about the gamma-ray scintillator, Pr3+:Lu3Al5O12 (LuAG). The second one was about neutron scintillator, Ce3+:6LiCaAlF6 and Eu2+:6LiCaAlF6 (6LiCAF). Those scintillators have been developed very recently for modern imaging applications in the medical and homeland security fields. In both cases, the rare earth ions are playing the crucial role as emission centers. Pr3+ in LuAG provided fast 5d→4f transition providing noticeably shorter decay time than that of Ce3+. Among several candidate hosts, LuAG showed the best performance. Bulk crystal growth, basic scintillation properties, two-dimensional gamma-ray imaging and positron emission mammography (PEM) application were demonstrated. Due to the international situation, the homeland security was compromized by illicit traffic of explosives, drugs, nuclear materials, etc. and the ways to its improvement became an important R&D topic. For this purpose the Ce and Eu doped LiCAF appeared competitive candidates. Especially, when substitution of 3He neutron detectors was considered, the discrimination ability of gamma-ray from alpha-ray was important. Bulk crystal growth, basic scintillation properties and two-dimensional neutron imaging were demonstrated.

Development of Neutron Diagnostic Systems for LHD Deuterium Experiments

T. Iguchi, A. Uritani, N. Nishio, J. Kawarabayashi, K. Watanabe, A. Yamazaki, H. Tomita, M. Sasao, A. Okamoto, S. Kitajima, K. Ishii, T. Nishitani, K. Ochiai, M. Ishikawa, K. Shinihara, J. H. Kaneko, F. Fujita, H. Harano, T. Matsumoto, E. Takada, M. Isobe, T. Tanaka, K. Nishimura, H. Yamanishi and M. Osakabe

Annual report of National Institute of Fusion Science page： 219 2011.11

Study on Measurement of Total Neutron Yield during Deuterium Experiments and its Calibration

A. Uritani, N. Nishio, J. Yamazaki, K. Watanabe, H. Yamanishi and M. Isobe

Annual report of National Institute of Fusion Science page： 108 2011.11

A Study on Electron Density Imaging Using the Compton Scattered X-ray CT Technique Reviewed

Ryota Masuji, Kenichi Watanabe, Atsushi Yamazaki, Akira Uritani

Nuclear Instruments and Methods in Physics Research Section A Vol. 652 ( 1 ) page： 620-624 2011.10

Language：English Publishing type：Research paper (scientific journal)

We propose a novel electron density imaging technique based on a Compton scattered X-ray CT (CSX-CT)
technique. We design fundamental configuration of the CSX-CT system, which consists of a fan-shaped
X-ray beam, two-dimensional sensors for scattered X-ray detection, parallel plate collimators for limitation of the direction of scattered X-rays and a line sensor for the transmission of X-ray CT
(TX-CT). An image obtained by the TX-CT can be used to correct the attenuation effect of scattered X-rays.
Through Monte Carlo simulation modeling studies of the CSX-CT system, we demonstrate that the
utilization of the information of scattered X-rays is useful to obtain the electron density image. We
additionally confirm that the medical exposure irradiated in the CSX-CT is estimated to be lower than the maximum dose recommended in the guideline of some committees.

Neutron-Gamma Discrimination Based on Pulse Shape Discrimination in a Ce:LiCaAlF₆ Scintillator Reviewed

Atsushi Yamazaki, Kenichi Watanabe, Akira Uritani, Tetsuo Iguchi, Noriaki Kawaguchi, Takayuki Yanagida, Yutaka Fujimoto, Yuui Yokota, Kei Kamada, Kentaro Fukuda, Toshihisa Suyama, Akira Yoshikawa

Nuclear Instruments and Methods in Physics Research Section A Associated Equipment Vol. 652 ( 1 ) page： 435-438 2011.10

Language：English Publishing type：Research paper (scientific journal)

We demonstrate neutron-gamma discrimination based on a pulse shape discrimination method in a Ce:LiCAF scintillator. We have tried neutron-gamma discrimination using a difference in the pulse shape or the decay time of the scintillation light pulse. The decay time is converted into the rise time through an integrating circuit. A 252Cf enclosed in a polyethylene container is used as the source of thermal neutrons and prompt gamma-rays. Obvious separation of neutron and gamma-ray events is achieved using the information of the rise time of the scintillation light pulse. In the separated neutron spectrum, the gamma-ray events are effectively suppressed with little loss of neutron events. The pulse shape discrimination is confirmed to be useful to detect neutrons with the Ce:LiCAF scintillator under an intense high-energy gamma-ray condition.

Development of a Gamma-Camera with a Functional Collimator Reviewed

Kenichi Watanabe, Junichi Sugiyama, Atsushi Yamazaki, Akira Uritani

Nuclear Instruments and Methods in Physics Research Section AAssociated Equipment Vol. 652 ( 1 ) page： 582-586 2011.10

Development of a Compact Flat Response Neutron Detector Reviewed

H. Harano, T. Matsumoto, J. Nishiyama, A. Masuda, A. Uritani, K. Kudo

Vol. 58 ( 5 ) page： 2421-2425 2011.10

Language：English Publishing type：Research paper (scientific journal)

Long counters are widely used as neutron fluence monitors for their flat response. However, a bulky neutron moderator is required to achieve the flat response, which can be a disadvantage for portability and an undesirable source of scattered neutrons. Reducing the size of the moderator degrades the flat response, especially for high-energy neutrons. We propose a new method to reduce the size of the moderator while keeping a flat response, and we develop a compact flat-response neutron detector. The detector consists of two small spherical $^{3}$ He proportional counters embedded at appropriate positions in a compact cylindrical polyethylene moderator. The sensitivity ratio between the two counters was adjusted to provide a flat response in the total outputs from the two counters. We demonstrated by MCNPX calculations and response measurements for Cf and Am-Be neutrons and monoenergetic neutrons that the present detector had a sensitivity comparable to long counters with a good flat response in a wide energy range up to 20 MeV while being only one-fifth of the weight of long counters. The positions of the effective center were determined as a function of neutron energy. We also proposed a method to evaluate the neutron energy using the detector, which will allow various new applications taking advantage of the ability to measure neutron fluence and energy at the same time.

DOI： 10.1109/TNS.2011.2163191

Flat-response Neutron Detector Using Spatial Distribution of Thermal Neutrons in a Moderator Reviewed

Kenichi Watanabe, Junpei Otsuka, Musashi Shigeyama, Yousuke Suzuki, Atsushi Yamazaki, Akira Uritani

Nuclear Instruments and Methods in Physics Research Section A Vol. 652 ( 1 ) page： 392-396 2011.10

Language：English Publishing type：Research paper (scientific journal)

We propose a novel neutron detector that realized flat-response using information of a spatial
distribution of thermal neutrons in a moderator. The proposed detector consists of a 3He position sensitive proportional counter(PSPC) and a cylindrical moderator surrounding the 3He PSPC. The
cylindrical detector is irradiated by neutrons along the cylinder axis. The spatial response of the 3He
PSPC is used to correct the detector response in to flat-response. We adopt a weighting method to
achieve flat-response, in which detected neutrons weighted depending on their detected positions are
accumulated as the detector response. Through Monte Carlo simulation studies, we confirm that the
flat-response neutron detector can be realized by correcting the response of the proposed detector
using the weights determined by a multiple least squar emethod (MLSM). Additionally, fundamental
property of the 3He PSPC is experimentally investigated to check applicability to the proposed flat-response neutron detector. We conclude that we should take account of the end effect when
determining the weights and correcting the detector response.

Europium and Sodium Codoped LiCaAlF₆ Scintillator for Neutron Detection Reviewed

Takayuki Yanagida, Akihiro Yamaji, Noriaki Kawaguchi, Yutaka Fujimoto, Kentaro Fukuda, Shunsuke Kurosawa, Atsushi Yamazaki, Kenichi Watanabe, Yoshisuke Futami, Yuui Yokota, Akira Uritani, Tetsuo Iguchi, Akira Yoshikawa, and Martin Nikl

Applied Physics Express 4 (2011) 126402 Vol. 4 page： 106401-106403 2011.9

Study on the Calibration of LHD Neutron Monitoring System Reviewed

Naoto Nishio, Atsushi Yamazaki, Kenichi Watanabe, Akira Uritani, Mitsutaka Isobe and Hirokuni Yamanishi

Plasma and Fusion Research Vol. 6 page： 2405115-1 - 2405115-4 2011.8

Language：English Publishing type：Research paper (scientific journal)

Neutron monitoring is quite important because neutron yield generated by fusion reactions corresponds to
the fusion output. In design of the neutron monitor, Monte Carlo simulations play an important role to make
corrections on various parameters, such as neutron energy spectrum and spatial distribution when determining the calibration constant. We consider the calibration procedures using a Cf point source toroidally rotating in the vacuum vessel, and evaluate uncertainties of the calibration constant for the neutron detector placed on the center
axis.

Basic Study of Europium Doped LiCaAlF₆ Scintillator and its Capability for Thermal Neutron Imaging Application Reviewed

Takayuki Yanagida, Noriaki Kawaguchi, Yutaka Fujimoto, Kentaro Fukuda, Yuui Yokota, Atsushi Yamazaki, Kenichi Watanabe, Jan Pejchal, Akira Uritani, Tetsuo Iguchi and Akira Yoshikawa

Vol. 33 ( 8 ) page： 1243-1247 2011.6

New Idea of a Small-Sized Neutron Detector with a Plastic Fibre Reviewed

Tetsuro Matsumoto, Hideki Harano, Akihiko Masuda, Jun Nishiyama, Yoshinori Sakurai and Akira Uritani

Radiation Protection Dosimetry Vol. 146 ( 1-3 ) page： 92-95 2011.4

Absolute Measurement of Activity of ¹⁹⁸Au Foils Using the 4πβ–γ Coincidence Counting Method and Corrections by the Monte Carlo Simulation Reviewed

Jun Nishiyama, Hideki Harano, Tetsuro Matsumoto, Yasushi Sato, Akira Uritani and Katsuhisa Kudo

Radiation Protection Dosimetry page： 1-5 2011.3

Recent Activities on Neutron Standardization in Japan

Hideki HARANO, Tetsuro MATSUMOTO, Jun NISHIYAMA, Akihiko MASUDA, Akira URITANI, Katsuhisa KUDO

Progress in NUCLEAR SCIENCE and TECHNOLOGY Vol. 1 page： 138-141 2011

Thermal Neutron Calibration Method Using an Intense Neutron Beam from JRR-3M Reviewed

T. Matsumoto, H. Harano, J. Nishiyama, H. Matsue, A. Masuda, A. Uritani and K. Kudo

Radiation Measurements Vol. 45 ( 10 ) page： 1124-1126 2010.12

Language：English Publishing type：Research paper (scientific journal)

We have developed a thermal neutron calibration method using a reactor produced neutron beam in JRR-3M of the Japan Atomic Energy Agency. Neutron-induced prompt gamma ray analysis has usually been performed in this beam line. Neutron energy distributions with negligible contributions from epithermal neutrons were measured by a time-of-flight method with a chopper made of 6LiF powder. The thermal neutron flux was determined by a gold foil activation method. We found that the thermal neutron beam in JRR-3M was well suited for calibration, neutron detector development or neutron dosimetry.

A Study on the Neutron Monitoring System of LHD Based on Monte Carlo Simulations Reviewed

N. Nishio, S. Yamamoto, K. Watanabe, A. Uritani, M. Isobe, and H. Yamanishi

Review of Scientific Instruments Vol. 81 page： 10D-306-1-10D-306-3 2010.10

Language：English Publishing type：Research paper (scientific journal)

Neutron monitoring is quite important because fusion neutrons are a direct evidence of fusion reactions. In calibration experiments of a neutron monitoring system, Monte Carlo calculations play an important role to correct various effects. To perform Monte Carlo calculations for a helical type fusion device, we make a program that can automatically generate an input file of a helical coil geometry for the MCNP code. The neutron spatial distributions and spectra for the helical devices are calculated in the geometries automatically generated by this program. We also discuss in calibration experiments.

Fusion Product Diagnostics Planned for Large Helical DeviceDeuterium Experiment Reviewed

M. Isobe, H. Yamanishi, M. Osakabe, H. Miyake, H. Tomita, K. Watanabe, H. Iwai, Y. Nomura, N. Nishio, K. Ishii, J. H. Kaneko, J. Kawarabayashi, E. Takada, A. Uritani, M. Sasao, T. Iguchi, Y. Takeiri and H. Yamada

Review of Scientific Instruments Vol. 81 page： 10D-310-1-10D-310-5 2010.10

Language：English Publishing type：Research paper (scientific journal)

Deuterium experiment on the Large Helical Device LHD is now being planned at the National Institute for Fusion Science. The fusion product diagnostics systems currently considered for installation on LHD are described in this paper. The systems will include a time-resolved neutron yield monitor based on neutron gas counters, a time-integrated neutron yield monitor based on activation techniques, a multicollimator scintillation detector array for diagnosing spatial distribution of neutron emission rate, 2.5 MeV neutron spectrometer, 14 MeV neutron counter, and prompt -ray diagnostics.

中性子測定器の校正技術 Invited

松本哲郎、原野英樹、工藤勝久、瓜谷章

放射線 Vol. 34 ( 2 ) page： 101-109 2008.4

中性子標準のトレーサビリティーと国際相互比較 Invited

原野英樹、松本哲郎、工藤勝久、瓜谷章

放射線 Vol. 34 ( 2 ) page： 111-115 2008.4

Development of the Fast Neutron Standard Using a Be(α,n) Reaction at the National Metrology Institute of Japan Reviewed

T. Shimoyama, H. Harano, T. Matsumoto, K. Moriyama, T. Hata, K. Kudo, T. Koyamada, and A. Uritani

Radiation Protection and Dosimetry Vol. 126 page： 130-133 2007.8

Characterization of Kilo Electron Volt Neutron Fluence Standard with the ⁴⁵Sc(p,n)⁴⁵Ti Reaction at NMIJ Reviewed

T. Matsumoto, H. Harano, T. Shimoyama, K. Kudo, and A. Uritani

Radiation Protection and Dosimetry Vol. 126 page： 155-158 2007.8

Language：English Publishing type：Research paper (scientific journal)

We are developing a national standard of a monoenergetic kilo electron volt neutron field with the 45Sc(p,n)45Ti resonance reaction. A wide resonance yields 27.4 keV neutrons at 0° with respect to the proton beam. The proton energy was precisely determined in the measurement of the relative neutron yield as a function of the proton energy from the threshold energy to 2.942 MeV. Absolute measurement of the monoenergetic neutron fluence was performed using a 3He proportional counter. Relative measurement was also carried out using a Bonner sphere calibrated at our 144 keV standard neutron field. Calibration factors were obtained between the count of a neutron monitor and the neutron fluence. A silicon-surface barrier detector with a 6LiF foil converter was also being developed for the neutron fluence measurement. Successful results were obtained in the tests in the 144 keV standard neutron field.

International Key Comparison of Neutron Fluence Measurements in Mono-energetic Neutron Fields: CCRI(III)-K10 Invited Reviewed

J Chen, Z Wang, C Rong, G Lövestam, A Plompen, N Puglisi, D M Gilliam, C M Eisenhauer, J S Nico, M S Dewey, K Kudo, A Uritani, H Harano, N Takeda, D J Thomas, N J Roberts, A Bennett, P Kolkowski, N N Moisseev, I A Kharitonov, S Guldbakke, H Klein

Metrologia Vol. 44 page： 58 2007

Language：English

CCRI Section III (neutron measurements) conducted a unique key comparison of neutron fluence measurements in mono-energetic neutron fields. In contrast to former comparisons, here the fluence measurements were performed with the participants' instruments in the same neutron fields at the PTB accelerator facility. Seven laboratories - the CIAE (China), IRMM (EC), NMIJ (Japan), NIST (USA), NPL (UK), PTB (Germany) and the VNIIM (Russia) - employed their primary standard reference methods or transfer instruments carefully calibrated against their primary standards, to determine the fluence of 0.144 MeV, 1.2 MeV, 5.0 MeV and 14.8 MeV neutrons and reported calibration coefficients for a selected neutron monitor and each neutron energy with a detailed uncertainty budget for the measurements. The key comparison reference values (KCRV) were finally evaluated as the weighted mean values of the neutron fluence at 1 m distance from the target in vacuum per neutron monitor count. The uncertainties of each KCRV amounted to about 1%. The degree of equivalence (DoE), defined as the deviation of the result reported by the laboratories for each energy from the corresponding KCRV, and the associated expanded uncertainty are also reported. The deviations between the results of two laboratories each with the corresponding expanded uncertainties complete the documentation of the degrees of equivalence.

Convenient Method of Relative Calibration of the Neutron Source Emission Rate between Ddifferent Source Types Reviewed

H.Harano, T.Matsumoto, T.Shimoyama,Y. Sato, A. Uritani, Y.Hino, K. Kudo, T.Michikawa

Nuclear Science, IEEE Transactions on Vol. 53 ( 3 ) page： 1413 - 1417 2006.6

Language：English Publishing type：Research paper (scientific journal)

Neutron source emission rates are determined by absolute or relative measurement. The relative measurement is performed by comparing between a sample source and a calibrated reference source of the same type. In this calibration, the energy spectra of the sample and reference sources should be identical, since normally there exists energy dependence in the response of neutron detectors. We propose a method of relative calibration of the neutron source emission rate between different source types and spectra. In the present method, a sample source or a calibrated reference source is located at the center of a graphite pile and thermal neutron flux at a special position is monitored and compared. We performed gold foil activation measurements at the NMIJ/AIST graphite pile and revealed that the thermal neutron flux at that position per unit source emission rate is independent of the types of neutron sources. The details of the physical mechanism were examined by calculating the spectral fluence of the neutrons thermalized inside the graphite pile using the MCNP4C code. We demonstrated this method using Am-Be, Ra(α)-Be, Cf, Pu-Be neutron sources and obtained the successful results which agreed within 1%.

Development of Dynamic Three-Dimensional Multi-Pinhole Gamma Camera Reviewed

Hisato Takemoto, Kenichi Watanabe, Jun Kawarabayashi, Tetsuo Iguchi and Akira Uritani

Vol. 43 ( 4 ) page： 344-347 2006.4

Language：English Publishing type：Research paper (scientific journal)

In this paper we propose a dynamic 3-D gamma camera consisting of multi-pinhole collimators and flat panel detectors. Through simulation studies on various pinhole configurations we determined that from a spatial and time resolution consideration, pinhole collimators with a 60° opening angle achieved acceptable dynamic 3-D imaging results. With regard to basic system performance, we estimated that the spatial and time resolution exceeds 3.5 mm and 4 s, respectively, for a small animal injected with 99mTc with an activity of 37 MBq. In addition, from further experiments we concluded that the proposed system would be acceptable and practical as a dynamic 3-D imager for nuclear medicine applications although position calibration concerns require further study.

Improvement of Photon Collection Uniformity from an NE213 Scintillator Using a Light Guide Reviewed

H.Harano, T.Matsumoto, Y.Shibata, Y. Ito, A.Uritani, K.Kudo

Nuclear Science, IEEE Transactions on Vol. 52 ( 6 ) page： 3147 - 3150 2005.12

Language：English Publishing type：Research paper (scientific journal)

The uniformity in collecting scintillation photons to the photomultiplier is one of the key parameters to carry out precise measurement using scintillators. A simple method is proposed to improve the collection uniformity of the scintillation photons just by inserting a light guide between a scintillator and a photomultiplier where the sidewall of the light guide is surrounded by a black paper as a photon absorber. This light guide insertion is expected to have a function to reduce the collection efficiency of the scintillation photons generated closer to the photomultiplier due to the larger transmission loss, since a decrease of the angle of incidence raises the fraction of the photons escaping from the sidewall of the light guide. The experiments using an NE213 liquid organic scintillation detector and gamma-ray sources revealed that the light guide functioned as a compensator for the original tendency of the photon collection and improved the photon collection uniformity. The details of the physical mechanism were examined by simulating the behavior of the gamma rays using the EGS4 electron-photon transport Monte Carlo code and the light propagation process using the ray-tracing program GuideM. The effects of the light guide were also examined on the whole energy resolution and the discrimination capability to separate gamma rays and neutrons.

Fast Neutron Spectrometer Composed of PSPCs and Si(Li)-SSDs with Excellent Energy Rresolution and Detection Efficiency Reviewed

T.Matsumoto, H. Harano, A. Uritani, K.Kudo

IEEE Transactions on Nuclear Science Vol. 52 ( 6 ) page： 2923 - 2926 2005.12

Language：English Publishing type：Research paper (scientific journal)

We have developed a fast neutron spectrometer composed of three position-sensitive proportional counters (PSPCs) with methane gas and two Si(Li) surface barrier semiconductor detectors (SSDs). A collimated incident neutron beam interacts with hydrogen atoms in the methane gas to generate recoil protons. Position information of the recoil protons obtained from the PSPCs gives the recoil angle. At the same time, the energy of the recoil protons is measured with the three PSPCs and the two SSDs. Finally, the neutron energy is derived using the recoil-proton energy and the recoil angle. This spectrometer was experimentally tested using a monoenergetic neutron beam with energy of 5.0 MeV. The energy resolution and the detection efficiency were 3.5% and 1.1 times10-3 %, respectively. The energy resolution could be achieved better than 2% by selecting events under proper conditions. We also developed a Monte Carlo code to evaluate the characteristics of the spectrometer. The results obtained from these simulations are compared to those obtained through experiments.

中性子検出器の開発動向　―スペクトロメータを中心に―

瓜谷章

放射線 Vol. 31 ( 4 ) page： 273-278 2005.10

Development of Compact Compton Gamma Camera for Non-destructive Detection and Location of Hidden Explosives with Neutron Induced Prompt Gamma-Ray Imaging

T. Iguchi, J. Kawarabayashi, K. Watanabe, H. Kenjyo, A. Uritani

Nuclear Science Symposium Conference Record, 2005 IEEE Vol. 2 page： 735 - 739 2005.10

Language：English

As a unique gamma-ray sensor for detection and location of hidden explosives with neutron induced prompt gamma-ray analysis, we are developing a compact and efficient Compton gamma camera based on stacked BGO scintillator rods to deduce the incident direction of characteristic 10.8 MeV gamma-rays produced from nitrogen abundant in explosives through neutron capture reaction. The detector unit consists of 5.4 mm times; 5.4 mm times 150 mm BGO scintillator rods stacked into an 8times8 array and two multi-anode photomultiplier tubes mounted at the both ends, which can measure three-dimensional position and intensity of scintillations produced through Compton multiple scattering inside the detector and follow the track of scattered gamma-rays backward according to Compton scattering kinematics to estimate the location of a specific energy gamma-ray source without any mechanical collimation. We have designed and constructed the prototype system of 6 detector units with multi-functional ASIC for multichannel signal read-out. The outline and applicability of this system is presented with some preliminary performance tests by using quasi-monochromatic 10.8 MeV gamma-ray beams produced through laser-Compton scattering with the electron storage ring.

Convenient Method of Relative Calibration of the Neutron Source Emission Rate between Ddifferent Source Types

H. Harano, T. Matsumoto, T. Shimoyama, Y. Sato, A. Uritani, Y. Hino, K. Kudo, T. Michikawa

Nuclear Science Symposium Conference Record, 2005 IEEE Vol. 1 page： 524 - 528 2005.10

Language：English

Neutron source emission rates are determined by absolute or relative measurement. The relative measurement is performed by comparing between a sample source and a calibrated reference source of the same type. In this calibration, the energy spectra of the sample and reference sources should be identical, since normally there exists energy dependence in the response of neutron detectors. We propose a method of relative calibration of the neutron source emission rate between different source types and spectra. In the present method, a sample source or a calibrated reference source is located at the center of a graphite pile and thermal neutron flux at a special position is monitored and compared. We performed gold foil activation measurements at the NMIJ/AIST graphite pile and revealed that the thermal neutron flux at that position per unit source emission rate is independent on the types of neutron sources. The details of the physical mechanism were examined by calculating the spectral fluence of the neutrons thermalized inside the graphite pile using the MCNP4C code. We demonstrated this method using Am-Be, Ra(alpha)-Be, Cf, Pu-Be neutron sources and obtained the successful results which agreed within 1%.

Development of a Novel Small-Sized Neutron Detector Based on a ⁶Li-Glass Scintillator

T. Matsumoto, H. Harano, T. Shimoyama, A. Uritani, Y. Sakurai, K. Kudo

Nuclear Science Symposium Conference Record, 2005 IEEE Vol. 3 page： 1291 - 1293 2005.10

Language：English

A small-sized thermal neutron detector based on a 6Li-glass scintillator and a plastic optical fiber was developed for measurement of a dose distribution of thermal neutrons in a thermal-neutron standard field. A contribution of gamma rays can not completely be neglected in the neutron measurement with this detector, although the 6Li-glass scintillator is distinguishable for the neutrons and the gamma rays by difference of each pulse height. Moreover, to reduce an uncertainty of neutron counts caused by the gamma ray background around a discrimination level, we suggested a gamma-ray suppression type of a small-sized thermal neutron detector with a 6Li-glass scintillator, a hollow CsI(Tl) scintillator and plastic optical fibers. The detector can reject signals due to the gamma rays with an anti-coincidence method. In the present paper, we evaluated the gamma-ray suppression ability of the detector using the EGS4 electron-photon transport Monte-Carlo code with the PRESTA routine. As the results, the sufficient gamma-ray suppression effect was shown.

トレーサブルな中性子計測と国際比較 Invited

工藤勝久、瓜谷章、原野英樹、松本哲郎、戸田泰弘

放射線 Vol. 31 ( 2 ) page： 105-110 2005.4

Fast Neutron Spectrometer Composed of Position-Sensitive Proportional Counters and Si(Li)-SSDs with Excellent Energy Resolution and Detection Efficiency

Progress Report Vol. 194/U page： 91 2005.3

Development of Real-time Thermal Neutron Monitor Using Boron-Loaded Plastic Scintillator with Optical Fiber for Boron Neutron Capture Therapy Reviewed

M. Ishikawa, K. Ono, Y. Sakurai, H. Unesaki, A. Uritani, G. Bengua, T. Kobayashi, K. Tanaka ,T. Kosako

Applied Radiation and Isotopes Vol. 61 ( 5 ) page： 775-779 2004.11

Language：English Publishing type：Research paper (scientific journal)

A new thermal neutron monitor for boron neutron capture therapy was developed in this study. We called this monitor equipped boron-loaded plastic scintillator that uses optical fiber for signal transmission as an [scintillator with optical fiber] SOF detector. A water phantom experiment was performed to verify how the SOF detector compared with conventional method of measuring thermal neutron fluence. Measurements with a single SOF detector yielded indistinguishable signals for thermal neutrons and gamma rays. To account for the gamma ray contribution in the signal recorded by the SOF detector, a paired SOF detector system was employed. This was composed of an SOF detector with boron-loaded scintillator and an SOF detector with a boron-free scintillator. The difference between the recorded counts of these paired SOF detectors was used as the measure of the gamma ray contribution in the measured neutron fluence. The paired SOF detectors were ascertained to be effective in measuring thermal neutron flux in the range above 106 (n/cm2/s).

Development of a Tiny Neutron Probe with an Optical Fiber for BNCT

KURRI Progress Report 2003 page： 133 2004.10

Fast Neutron Spectrometer Composed of Position-Sensitive Proportional Counters and Si(Li)-SSDs with Excellent Energy Resolution and Detection Efficiency

T. Matsumoto, H. Harano, A. Uritani, K. Kudo

Nuclear Science Symposium Conference Record, 2004 IEEE Vol. 2 page： 715 - 719 2004.10

Language：English

We have developed a fast neutron spectrometer composed of three position-sensitive proportional counters (PSPCs) with methane gas and two Si(Li) detectors. A collimated incident neutron interacts with a hydrogen atom in the methane gas to generate a recoil proton. Position information on the recoil proton obtained from the PSPCs gives the recoil angle. At the same time, the energy of the recoil proton is measured with the three PSPCs and the Si(Li) detectors. Finally, the neutron energy is derived using the recoil-proton energy and the recoil angle. This spectrometer was experimentally tested using a monoenergetic neutron beam with energy of 5.0 MeV. The energy resolution and the detection efficiency were 3.5% and 1.1×10-5, respectively. The energy resolution better than 2% could be achieved by selecting events under proper conditions. We also developed a Monte-Carlo code in order to evaluate the characteristics of the spectrometer. The calculation results were compared with the experimental ones.

Improvement of Photon Collection Uniformity from an NE213 Scintillator Using a Light Guide

H. Harano, T. Matsumoto, Y. Shibata, Y. Ito, A. Uritani, K. Kudo

Nuclear Science Symposium Conference Record, 2004 IEEE Vol. 2 page： 841 - 845 2004.10

Language：English

The uniformity in collecting scintillation photons to the photomultiplier is one of the key parameters to carry out precise measurement using scintillators. A simple method is proposed to improve the collection uniformity of the scintillation photons just by inserting a light guide between a scintillator and a photomultiplier where the sidewall of the light guide is surrounded by a black paper as a photon absorber. This light guide insertion is expected to have a function to reduce the collection efficiency of the scintillation photons generated closer to the photomultiplier due to the larger transmission loss, since a decrease of the angle of incidence raises the fraction of the photons escaping from the sidewall of the light guide. The experiments using an NE213 liquid organic scintillation detector and gamma-ray sources revealed that the light guide functioned as a compensator for the original tendency of the photon collection and improved the photon collection uniformity. The details of the physical mechanism were examined by simulating the behavior of the gamma rays using the EGS4 electron-photon transport Monte-Carlo code and the light propagation process using the ray-tracing program GuideM. The effects of the light guide were also examined on the whole energy resolution and the discrimination capability to separate gamma rays and neutrons.

Construction of 144, 565 keV and 5.0 MeV Monoenergetic Neutron Calibration Fields at JAERI Reviewed

Y. Tanimura, M. Yoshizawa, J. Saegusa, S. shimizu, M. Yoshida, Y. shibata, A Uritani, K Kudo

Radiat Protection and Dosimetry Vol. 110 page： 85-89 2004.9

Language：English Publishing type：Research paper (scientific journal)

Monoenergetic neutron calibration fields of 144, 565 keV and 5.0 MeV have been developed at the Facility of Radiation Standards of JAERI using a 4 MV Pelletron accelerator. The 7Li(p,n)7Be and 2H(d,n)3He reactions are employed for neutron production. The neutron energy was measured by the time-of-flight method with a liquid scintillation detector and calculated with the MCNP-ANT code. A long counter is employed as a neutron monitor because of the flat response. The monitor is set up where the influence of inscattered neutrons from devices and their supporting materials at a calibration point is as small as possible. The calibration coefficients from the monitor counts to the neutron fluence at a calibration point were obtained from the reference fluence measured with the transfer instrument of the primary standard laboratory (AIST), a 24.13 cm Bonner sphere counter. The traceability of the fields to AIST was established through the calibration

Development of a Tiny Neutron Pprobe with an Optical Fibre for BNCT Reviewed

Y. Ito, G. Katano, H. Harano, T. Matsumoto, A. Uritani, K. Kudo, K. Kobayashi, T. Yoshimoto, Y. Sakurai, T. Kobayashi, and C. Mori

Radiat Protection and Dosimetry Vol. 110 ( 1-4 ) page： 619-622 2004.8

Characterization of Gamma Rays Existing in the NMIJ Standard Neutron Field Reviewed

H. Harano, T. Matsumoto, Y. Ito, A. Uritani, and K. Kudo

Radiat Protection and Dosimetry Vol. 110 ( 1-4 ) page： 69-72 2004.8

Development of a Fast Neutron Spectrometer Composed of Silicon-SSD and Position-Sensitive Proportional Counters Reviewed

T. Matsumoto, H. Harano, Y. Ito, A. Uritani, K. Emi, and K. Kudo

Radiat Protection and Dosimetry Vol. 110 ( 1-4 ) page： 223-226 2004.8

Language：English Publishing type：Research paper (scientific journal)

A new fast neutron spectrometer has been developed. The spectrometer is composed of a silicon surface barrier detector and three position-sensitive proportional counters with methane gas working as counting gas and a radiator. A collimated incident neutron interacts with a hydrogen atom in the methane gas to generate a recoil proton. The position information on the path of the recoil proton obtained from the three position-sensitive proportional counters gives the recoil angle. In the meanwhile, the energy of the recoil protons is measured with the three proportional counters and the silicon surface barrier detector. The characteristics of the spectrometer were evaluated with a monoenergetic neutron beam. The best energy resolution was 1.8% for 5.0 MeV neutrons.

DOI： 10.1093/rpd/nch125

産総研電子蓄積リングＴＥＲＡＳの現状

後神進史、豊川弘之、小池正記、渡辺一寿、座間達也、池浦広美、齋藤則生、粟津浩一、瓜谷章、鈴木功、齋藤輝文

page： 203-205 2004.8

Language：Japanese

産総研の電子蓄積リングTERASは760MeVの定常運転による放射光の他に、円偏光放射光やレーザー逆コンプトンγ線源としても利用されている。TERASにおいて、ここ一年間に行ったKickerやRF等の機器改良による蓄積電流量の向上、電子ビーム安定化、放射光利用環境の改善点、及び放射光利用による各研究成果等について報告する。

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 ) page： 2-5 2004.1

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

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

Nucl. Instr. and Methods Vol. B213 page： 305-309 2004.1

Language：English Publishing type：Research paper (scientific journal)

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 Reviewed

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 Vol. 68 ( 7 ) page： 072001-1-072001-6 2003.10

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

KURRI Progress Report 2002 page： 129 2003.10

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 Vol. 2 page： 1355 - 1357 2003.10

Language：English

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 page： 340-344 2003.8

Development of Three-Dimensional Gamma Camera with Imaging Plates and Multi-Pinhole Collimators Reviewed

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 Vol. A505 ( 1-2 ) page： 577-581 2003.6

Language：English Publishing type：Research paper (scientific journal)

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 Vol. INDC(JPN) ( 190/U ) page： 59-62 2003.3

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 page： 21-24 2003.3

Language：Japanese Publishing type：Research paper (scientific journal)

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 ) page： 97-107 2002.12

Language：Japanese

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

Vol. 17 ( 8 ) page： 71 2002.8

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 Vol. 37 ( 2 ) page： 118-127 2002.6

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

Japanese Nuclear data Committee, Progress Report Vol. INDC(JPN) ( 189(U) ) page： 65-33 2002.3

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 Vol. 28 ( 1 ) page： 55-60 2002.1

Radiation Distribution Sensing with Normal Optical Fiber Reviewed

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 Vol. 48 ( 6 ) page： 2348-2351 2001.12

Language：English Publishing type：Research paper (scientific journal)

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 Reviewed

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

Journal of Nuclear Science and Technology Vol. 38 ( 10 ) page： 844-849 2001.10

Digital Waveform Analysis for ³He Ion Chamber Reviewed

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

IEEE Transactions on Nuclear Science Vol. 48 ( 3 ) page： 527-529 2001.6

Language：English Publishing type：Research paper (scientific journal)

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 Reviewed

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

Journal of Nuclear Science and Technology Vol. 38 ( 5 ) page： 301-305 2001.5

Language：English Publishing type：Research paper (scientific journal)

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 Reviewed

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

Journal of Nuclear Science and Technology Vol. 38 ( 5 ) page： 306-311 2001.5

Language：English Publishing type：Research paper (scientific journal)

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 Reviewed

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

Nucl. Instr. and Methods Vol. A462 ( 3 ) page： 405-410 2001.4

Conceptual Design of Compact Neutron Camera with Directional Neutron Detector for Nuclear Fusion Experimnt Reviewed

T. Iguchi, T. Iizuka, A. Uritani and J. Kawarabayashi

Fusion Technol. Vol. 39 ( 2 ) page： 1147-1151 2001.3

Pulse Shape Analysis on Mixed Beta Particle and Gamma-ray Source Measured by CdZnTe Semiconductor Detector by Means of Digital-Analog Hybrid Signal Processing Method Reviewed

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

Journal of Nuclear Science and Technology Vol. 38 ( 5 ) page： 306-311 2001.3

Database for WWER-1000 Reactor Pressure Vessel IAEA Regional Project RER4/017

B. Osmera, V. Lyssakov, F. Cvachvec, F. Hudec, B. Jansky, J. Mikus, E. Novak, S. Posta, Z. Turzik, M. Hort, V. Krysl||SKODA, V. Smutny, S. Zaritsky, N. Alekseev, M. Gurevitch, A. Egorov, E. Brodkin, K. Ilieva, S. Belousov, J. Kovbasenko, A. Uritani, T. Misawa, C. Mori

ASTM/STP Vol. 1398 page： 312-319 2001.2

A Novel Neutron Spectrometer with Response of Wide Energy Range

ASTM/STP Vol. 1398 page： 698-705 2001.2

Development of Neutron and Gamma-Ray Flux Distribution Measurement System with Scintillator and Optical Fiber Combination

C. Mori, A. Uritani, T. Iguchi, S. Hayashi, Y. Takami, I. Kimura, M. Katagiri

ASTM/STP Vol. 1398 page： 769-774 2001.2

Simultaneous Measurement of Neutron Pulse Series in Time and Space by Using Position Sensitive Proportional Counter

ASTM/STP Vol. 1398 page： 811-818 2001.2

JT60Uにおける飛行時間型中性子スペクトロメータ

柴田康成，井口哲夫，瓜谷章，河原林順，Magnus Hoek，西谷建夫，森岡篤彦

放射線 Vol. 27 ( 1 ) page： 27-29 2001.1

Neutron Energy Spectrum Estimation Method with Information on Direction of Neutron Incidence at Spaceborne Neutron Monitor

Y. Makihara, A. Uritani, T. Iguchi, J. Kawarabayashi, H. Toyokawa, N.Takeda, K. Kudo, S. Sato, S. Takagi, S. Iwai and C. Mori

Proc. of 15th Workshop on Rsdistion Detectord and Their Uses Vol. 2001 ( 20 ) page： 140-149 2001

Digital Waveform Analysis for ³He Ionization Chamber

J. Kawarabayashi, M. P. Mardiyanto, A. Uritani, T. Iguchi, J. Kaneko, H. Takeuchi

Nuclear Science Symposium Conference Record, 2000 IEEE Vol. 2 page： 9/193 - 9/195 2000.10

Radiation Distribution Sensing with Normal Optical Fiber

R. Naka, J. Kawarabayashi, A. Uritani, T. Iguchi, J. Kaneko, H. Takeuchi, T. Kakuta

Nuclear Science Symposium Conference Record, 2000 IEEE Vol. 1 page： 6/231 - 6/234 2000.10

Language：English

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 cm, 37 cm and 13 cm, respectively. The detection efficiencies for the beta rays, the 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 Directional Neutron Detector for Compact Fast Neutron Camera

T. Iguchi, S. Iizuka, A. Uritani, J. Kawarabayashi

Nuclear Science Symposium Conference Record, 2000 IEEE Vol. 1 page： 6/207 - 6/210 2000.10

Language：English

A new concept of compact neutron camera with directional neutron detector arrays is proposed for nuclear fusion experiment. The basic performance of the directional neutron detector is made clear through experiment for a prototype detector with 14 MeV neutrons and design consideration of the detector specification to optimize its directionality. The results show that the angle resolution defined as a full width of neutron incident angles at a half maximum of detector counts would reach up to around 4 degrees at minimum around 45 degrees neutron incidence to the detector axis. The concept for a compact neutron camera is also given by making good use of an array of the optimized directional neutron detectors.

Evaluation of Response Functions of 16"x16"x4" NaI Scintillation Detector for Environmental Gamma-ray Survey

H. Itadzu, T. Iguchi, A. Uritani and J. Kawarabayashi

Proceedings of the Second International Workshop on EGS page： 250-254 2000.8

円錐状突起電極型放射線画像検出器の開発

寿山大介、河原林順、瓜谷章、井口哲夫

放射線 Vol. 26 ( 2 ) page： 77-80 2000.4

通常光ファイバーを用いた放射線分布センシングに関する基礎研究

中亮太郎、河原林順、瓜谷章、井口哲夫、金子純一、竹内浩、角田恒巳

放射線 Vol. 26 ( 2 ) page： 71-75 2000.4

Improvement of Energy Spectrum Characteristics of CdZnTe Semiconductor Detector with a Digital-analog Fusion Method Reviewed

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

Nucl. Instr. and Methods Vol. A441 ( 3 ) page： 483-488 2000.3

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

We present a new application of a `Fusion Method' to improve gamma-ray energy spectrum characteristics of a CdZnTe semiconductor detector. A digital and an analog system are simultaneously applied for the detector output; The digital system digitizes the signal pulse shapes for pattern recognition based on a neural network algorithm. The analog measures the signal pulse heights with a conventional analog system. The digital and the analog output data are fused and then used for improvement of the energy spectrum characteristics, i.e. the photopeak area, the peak-to-valley ratio, and the FWHM of photopeaks.

Pulse Shape Analysis Based on Similarity and Neural Network with Digital-Analog Fusion Method

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

Proc. 14th W. S. on Radiation Detectors and Their Uses, KEK Proc. Vol. 2000 page： 132-141 2000

Development of Failed Fuel Detection and Location Technique Using Resonance Ionization Mass Spectrometry: Improvement of the Detection Limit with Pulsed Supersonic Valve

Kenichi Watanabe, Tetsuo Iguchi, Toshiyuki Ogita, Takeshi Watanabe, Akira Uritani, Jun Kawarabayashi, Hideki Harano and Shoichi Nose

Proc. 14th W. S. on Radiation Detectors and Their Uses, KEK Proc. Vol. 2000 ( 14 ) page： 183-190 2000

Neutron/Proton Discrimination Characteristics of Spaceborne Neutron Monitors,

Y. Makihara, A. Uritani, T. Iguchi, J. Kawarabayashi, H. Toyokawa, Y. Uwamino, O. Sato, S. Takagi, S. Iwai and C. Mori

Proc. 14th W. S. on Radiation Detectors and Their Uses, KEK Proc Vol. 2000 ( 14 ) page： 155-162 2000

Pulse Shape Recognition for CdZnTe Semiconductor Detector by using Multi-shaping Amplifiers Method with Neural Network Algorithm Reviewed

H. Sakai, A. Uritani, C. Mori and T. Iguchi

IEEE Trans. Nuclear Science Vol. NS-46 ( 4 ) page： 806-809 1999.8

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A new pulse shape recognition method with multi-shaping amplifiers, combined with a neural network algorithm, has been developed, where four pulse heights are sampled from one signal pulse through four linear amplifiers with different shaping time constants. The four pulse heights are used as characteristic parameters to recognize the pulse shape with a neural network. This method has been applied to signal processing for a CdZnTe semiconductor detector to improve the deteriorated energy spectra caused by pulse height deficits due to the different mobilities of electrons and holes in the detector. The neural network recognizes the pulse shape patterns and provides the corrective magnification factors of the pulse heights. After the corrective procedure, the energy spectrum for 137Cs gamma-rays is improved from 9.3 keV to 7.4 keV in the energy resolution (FWHM) of the 662 keV gamma rays photopeak. The photopeak becomes a considerably symmetrical shape without a low-energy tail. It has been verified that this method is simple and useful for pulse shape analyses, which can be used for many other applications.

Measurement of the Thermal and Fast Neutron Flux in a Research Reactor with a Li and Th Loaded Optical Fibre Detector Reviewed

Y. Yamane, A. Uritani, T. Misawa, J. K-H. Karlsson and I. Pazsit

Nucl. Inst. and Methods Vol. A432 ( 2-3 ) page： 403-409 1999.8

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

The spatial dependence of thermal and fast neutron flux was measured axially in the core of a 1 MW research reactor. The measurements were made by a thin optical fibre detector with a neutron sensitive ZnS(Ag) scintillation tip. For thermal neutrons 6Li was used, whereas for fast neutrons 232Th was used as neutron converter. The spatial dependence was measured by moving the fibre axially with a uniform speed. The measurement takes a few minutes, compared to up to 10 h with the conventional wire activation method. Comparison with traditional measurements shows a good agreement.

放射線検出器のニューラルネットワーク波形識別におけるデータ入力間隔の最適化

酒井宏隆、瓜谷章、井口哲夫

放射線 Vol. 25 ( 2 ) page： 115-122 1999.4

Spherical Neutron Detector for Space Neutron Measurement Reviewed

S. Yamaguchi, A. Uritani, H. Sakai, C. Mori, T. Iguchi, H. Toyokawa, N. Takeda and K. Kudo

Nucl. Instr. and Methods Vol. A422 ( 1-3 ) page： 600-605 1999.2

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A novel neutron detector has been developed to measure energy spectra of space neutrons in a spaceship. The detector consists of a spherical polyethylene moderator with a diameter of 30 cm and 19 pairs of 6Li- and 7Li-glass scintillators arranged along the orthogonal x-, y-, and z-axes of the sphere. The pairs can distinctively detect thermal neutrons in some radiation fields, where other radiation exists, by subtracting the number of detected events of the 7Li-glass scintillator from that of the 6Li-glass one. Hence the detector can clearly obtain the thermal neutron flux distribution in the spherical moderator even in such fields. The detector was applied to the measurement of monoenergetic and 252Cf neutrons. The characteristics of the detector were studied by comparison with the simulations.

Time-Spatial Neasurement by Using Position-Sensitive ³He Proportional Counter

Y. Kitamura, T. Misawa, H. Unesaki, S. Shiroya, A. Uritani and K. Ishitani

Nucl. Instr. and Methods Vol. A422 ( 1-3 ) page： 64-68 1999.2

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Time-spatial neutron measurement was carried out by using a position-sensitive 3He proportional counter (PSPC) in the Kyoto University Critical Assembly. The data of the output pulses from the PSPC were acquired by a data acquisition system which was based on the LN-9000 system of Laboratory Equipment Corporation. In this system, the time and the position data of the neutron detection pulses were simultaneously accumulated by a personal computer. In the present study, the Rossi-α method, which was derived for time-domain neutron correlation analysis, was extended in order to process the measured two-dimensional data of time and space. The processed experimental results and a theoretical formula based on the one-group diffusion approximation neglecting the higher modes agreed well with each other, which indicates the present system is applicable for reactor physics experiments including reactor kinetics.

High Energy Resolution Spectrometer with Propotrional Counter and Si-Detector Telescope Type for 14MeV Neutrons in Plasma Diagnostics Reviewed

C. Mori, J. Goto, A. Uritani, H. Miyahara, Y. Ikeda, Y. Kasugai, J. Kaneko, M. Sasao, Y. Sakuma, K. Kudo and N. Takeda

Nucl. Instr. and Methods Vol. A422 ( 1-3 ) page： 75-78 1999.2

Measurement of Neutron and Gamma Ray Intensity Distributions with an Optical Fiber-Scintillator Detector

C. Mori, A. Uritani, H. Miyahara, T. Iguchi, S. Shiroya, K. Kobayashi, E. Takada, R. F. Flemming, Y. K. Dewaraja, D. Stuenkel, G. F. Knoll

Nucl. Instr. and Methods Vol. A422 ( 1-3 ) page： 129-132 1999.2

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

On the tip of an optical fiber, a very small amount of ZnS(Ag) scintillator mixed with neutron converter and adhesive paste was painted, which can be inserted into a narrow space and moved by a fiber-driving unit controlled with a personal computer. The presented method made it possible to measure neutron flux distributions in critical assemblies, research reactors or other neutron facilities with position resolution of less than 1 mm and in 10 min or so over a meter. As neutron converter, 6Li and 235U are good for thermal neutrons and 232Th is useful for fast neutrons. When a neutron converter is not used, the method can be applied to the measurement of γ-ray intensity distribution.

New Pulse Shape Analysis Method with Multi-shaping Amplifiers Reviewed

H. Sakai, A. Uritani. K. Inoue, Y. Takenaka, C. Mori and T. Iguchi

Nucl. Instr. and Methods. Vol. A421 ( 1-2 ) page： 316-321 1999.1

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A novel pulse-shape analysis method that uses similarity to recognize an individual pulse shape is presented in this paper. We obtain four pulse heights by using four linear amplifiers with different shaping time constants. We treat a combination of the four pulse heights as a pattern vector. A similarity of the pulse shape can be obtained by comparison between the pattern vector and a discriminant vector which was given in advance. Each pulse shape is analyzed by using the similarity. The method has been applied for the improvement of characteristics of a CdZnTe semiconductor detector. The characteristics of the energy spectrum of the CdZnTe detector such as the photopeak efficiency or the peak-to-valley ratio are improved after the correction procedure with the similarity.

コンプトンカメラによるガンマ線イメージング

瓜谷章

放射線 Vol. 25 ( 1 ) page： 87-92 1999.1

実践！放射線計測応用技術[6][原子炉分野]試験・研究炉、臨界装置、加速器炉

森千鶴夫、瓜谷章

原子力eye Vol. 45 ( 6 ) page： 64-67 1999

Pulse Shape Recognition for CdZnTe Semiconductor Detector by Using Multi-shaping Amplifiers Method with Neural Network Algorithm

H. Sakai, A. Uritani, C. Mori, T. Iguchi

Nuclear Science Symposium Conference Record, 1999 IEEE Vol. 1 page： 662 - 665 1998.10

Language：English

A new pulse shape recognition method with multi-shaping amplifiers, combined with a neural network algorithm, has been developed, where four pulse heights are sampled from one signal pulse through four linear amplifiers with different shaping time constants. The four pulse heights are used as characteristic parameters to recognize the pulse shape with a neural network. This method has been applied to signal processing for a CdZnTe semiconductor detector to improve the deteriorated energy spectra caused by pulse height deficits due to the different mobilities of electrons and holes in the detector. The neural network recognizes the pulse shape patterns and provides the corrective magnification factors of the pulse heights. After the corrective procedure, the energy spectrum for 137Cs gamma-rays is improved from 9.3 keV to 7.4 keV in the energy resolution (FWHM) of the 662 keV gamma ray photopeak. The photopeak becomes a considerably symmetrical shape without a low-energy tail. It has been verified that this method is simple and useful for pulse shape analyses, which can be used for many other applications.

Evaluation of Counting Loss and Its Correction for Small Pulses in the Internal Counting with Proportional Counters Reviewed

C. Mori, Y. Wu, T. Agemura, A. Uritani, H.Miyahara, T. Suzuki and M. Yoshida

International J. Applied Radiation and Isotopes Vol. 49 ( 9-11 ) page： 1107-1111 1998.9

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

In the absolute radioactivity determination of gaseous samples using the internal gas counting method with proportional counters, evaluation of counting losses of pulses whose pulse heights are lower than the discrimination level is very important to obtain high accuracy. Counting losses due to wall effect and to very low energy of a β-ray were evaluated by experiment and EGS4 Monte Carlo calculation. The calculated results agreed well with experimental results when parameters in the EGS4 code were properly chosen; which shows the calculation code is able to be applied to other radioactive nuclides and other measurement conditions for the evaluation of counting losses.

Novel Pulse Shape Analysis Method by Using Similarity Reviewed

Y. Takenaka, A. Uritani , K. Inoue, H. Sakai and C. Mori

International J. Applied Radiation and Isotopes Vol. 49 ( 9-11 ) page： 1219-1223 1998.9

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A novel pulse-shape-analysis method that uses the similarity of patterns to recognize individual pulse shapes is presented. The principle of this method is described. The method has been applied to improve the gamma-ray energy spectrum of a CdZnTe semiconductor detector. The energy spectrum has been improved with increased photopeak efficiency and better energy resolution.

Improvement of Precision in Quantitative Measurement of Radioactivity with Imaging Plate Reviewed

T. Suzuki, C. Mori, K. Yanagida, A. Uritani, H.Miyahara, M. Yoshida and F. Takahashi

International J. Applied Radiation and Isotopes Vol. 49 ( 9-11 ) page： 1127-1130 1998.9

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

To obtain a high precision in radiation or radioactivity measurements with an imaging plate, the photo-stimulated luminescence intensity must be large. To get the highest intensity, we reread an imaging plate repeatedly and summed each intensity for the purpose of reducing the variation of the measured intensities. A great improvement of the precision in the measurement was achieved with the method of repeated readings when the time interval between each reading is more than about 1 h.

Measurement of Eigenvalue Separation by Using Position Sensitive Proportional Counter Reviewed

K. Ishitani, Y. Yamane, A. Uritani, T. Iguchi and S. Shiroya

Annals of Nuclear Energy Vol. 25 ( 10 ) page： 721-732 1998.6

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Eigenvalue separation is an important index of power reactor stability in the view of neutronics. In recent years, a long, slender Position Sensitive Proportional Counter has been developed. By using this proportional counter, the spatial neutron flux distribution of a nuclear reactor can be measured rapidly. Using these characteristics, we intend to develop the experimental method evaluating eigenvalue separation as an index for reactor stability. A method based on spatial integrals of neutron flux measured at a subcritical system with an external source is proposed. To verify this method, experiments were carried out at Kyoto University Critical Assembly. It was confirmed that eigenvalue separation can be evaluated within a relative error of 10%.

講座　放射線防護用機器　XVII.　放射線管理計測技術の最近の進歩　1.位置感応型検出器とその応用

瓜谷章、飯田孝夫、森千鶴夫

Vol. 47 ( 2 ) page： 155-165 1998

Pulse Shape Recognition with Neural Network Algorithm

H. Sakai, A. Uritani, C. Mori and T. Iguchi

Proceedings of the 12th Workshop on Radiation Detectors and Their Uses page： 28-37 1998

Improvement of Energy Spectrum Characteristics of CdZnTe Semiconductor Detector by means of Digital Waveform Processing with neural network algorithm Reviewed

H. Sakai, Y. Takenaka, A. Uritani, K. Inoue and C. Mori

Nuclear Instruments and Methods Vol. A400 ( 2-3 ) page： 401-408 1997.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

We have studied the improvement of gamma-ray energy spectrum characteristics of a CdZnTe semiconductor detector by means of a neural network algorithm. The neural network recognizes the pulse shapes and determines the corrective magnification factors of pulse heights. After the corrective procedure with the network, the gamma-ray energy spectra of some radioisotope sources become more ideal with better energy resolution.

Performance of a Spherical Neutron Counter for Spectroscopy and Dosimetry Reviewed

H. Toyokawa, M. Yoshizawa, A. Uritani, C. Mori, N. Takeda and K. Kudo

IEEE transaction Vol. NS-44 ( 3 ) page： 788-791 1997.6

Language：English Publishing type：Research paper (scientific journal)

A spherical neutron counter for spectroscopy and dosimetry has been developed. The counter consists of a spherical polyethylene moderator and three slender 3He position-sensitive proportional counters. Rough measurements of neutron fluence spectra and ambient dose equivalents, H*(10), have been done in the moderated-neutron field of JAERI. Characteristics of the counter are examined and compared with those of a Bonner sphere neutron spectrometer.

An Electronically Collimated Gamma Camera with a Parallel Plate Collimator for Tc-99m Imaging Reviewed

A. Uritani , N. H. Clinthorne, J. E. Gormley J. W LeBlanc, W L. Rogers, D. K. Wehe and S. J. Wilderman

IEEE Transaction Vol. NS-44 ( 3 ) page： 894-898 1997.6

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

We present a new idea to apply a parallel plate collimator to an electronically collimated gamma camera, to reduce the complexity of image reconstruction. Back projected images obtained experimentally and using Monte Carlo simulations are shown. Using the collimator, backprojected images of single low-energy gamma-ray emitters can be obtained with larger signal-to-noise ratio than those obtained without the collimator. The results show that this method is useful in obtaining Tc-99m images.

Characteristics and Correction of the Fading of Imaging Plate Reviewed

T. Suzuki, C. Mori, K. Yanagida, A. Uritani, H.Miyahara, M. Yoshida and F. Takahashi

J. Nucl. Sci. Technol. Vol. 34 ( 5 ) page： 461-465 1997.5

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

When the latent images formed by exposure with incident particles in the phosphor of Imaging Plate (IP) are irradiated with laser beam, photo-stimulated luminescence (PSL) is emitted and read through a photomultiplier. PSL intensity fades with increasing the elapsed time between the exposure and the PSL reading. When the IP is read successively, the PSL intensities decrease with the number of reading times. The tendency of the decreasing becomes gradual with increasing the elapsed time after exposure. The multiple successive reading method gives the means of the correction of the fading.

Characteristics of Prompt Scintillation from Imaging Plate Reviewed

T. Suzuki, C. Mori, K. Yanagida, A. Uritani, H.Miyahara, K. Takahashi, J. Miyahara, M. Yoshida and F. Takahashi

Nucl. Instr. and Methods Vol. A390 ( 1-2 ) page： 155-159 1997.5

A Spherical Neutron Counter with Extended-Energy Response for Dosimetry Reviewed

H. Toyokawa, A. Uritani, C. Mori, N. Takeda and K. Kudo

Radiation Protection Dosimetry Vol. 70 ( 1-4 ) page： 365-370 1997.4

New Position Sensing Method for Position-sensitive Proportional Counter with Neural Network Algorithm Reviewed

H. Sakai, A. Uritani, K. Inoue, Y. Takenaka and C. Mori

Nucl. Instr. and Methods Vol. A385 ( 2 ) page： 335-338 1997.1

Experimental and Calculational Evaluation of Energy Loss of Radiations in Radioisotope source and Nuclear Detector

C. Mori, H. Sakai, N. Takeuchi, T. Genka, Y. Wu, A. Uritani and H. Miyahara

Proc. the First International Workshop on EGS4 page： 206-214 1997

シンチレータ塗布・光ファイバーを用いた中性子束・γ線強度分布測定法の開発

森千鶴夫、影山一巳、槙林康雄、瓜谷章、宮原洋、柳田勝男、井口哲夫、三澤毅、山根義宏、小林圭二、代谷誠治、市原千博、林正俊、宇根崎博信、木村逸郎、吉井康司、高田英治、中澤正治

京都大学原子炉実験所第３１回学術講演会報文集 page： 221-226 1997

Development of Fast Neutron Spectrometer of Proportional Counter and Si-Detector Telescope Type Reviewed

C. Mori, M. Tojo, K. Yanagida, J. Goto, A. Uritani, H. Miyahara, Y. Wu, K. Kudo, N. Takeda, Y. Ikeda, Y. Kasugai, T. Iida, Y. Sakuma and M. Sasao

Fusion Technology Vol. 30 ( 3 ) page： 1134-1138 1996.12

方向依存応答を示す新型中性子測定器の線源スペクトル推定逆問題への適用

豊川弘之、瓜谷章、森千鶴夫、吉澤道夫、武田直人、工藤勝久

放射線 Vol. 22 ( 4 ) page： 29-38 1996.11

Neutron Spectrometer with Position-Sensitive Proportional Counters Reviewed

H. Toyokawa, A. Uritani, C. Mori, M. Yoshizawa, N. Takeda and K. Kudo

Nucl. Instr. and Methods Vol. A381 ( 2-3 ) page： 481-487 1996.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A spherical neutron counter for spectrometry and dosimetry has been developed. The counter consists of a spherical polyethylene moderator and three slender 3He position-sensitive proportional counters inserted into the moderator. The thermal neutron distribution in the moderator, which is a function of the energy of the incident neutrons is obtained with the proportional counters. Characteristics of the counter have been studied with experiments and Monte Carlo simulations. Also shown are energy spectra of a 252Cf neutron source that are obtained by an unfolding method using the thermal neutron distributions as response functions.

Performance of a Spherical Neutron Counter for Spectroscopy and Dosimetry

H. Toyokawa, M. Yoshizawa, A. Uritani, C. Mori, N. Takeda, K. Kudo

Nuclear Science Symposium Conference Record, 1996 IEEE Vol. 2 page： 856 - 859 1996.10

Language：English

A spherical neutron counter for spectroscopy and dosimetry has been developed. The counter consists of a spherical polyethylene moderator and three slender 3He position-sensitive proportional counters. Rough measurements of neutron fluence spectra and ambient dose equivalents, H*(10), has been done in the moderated-neutron field of JAERI. Characteristics of the counter are examined and compared with those of a Bonner sphere neutron spectrometer.

An Electronically-Collimated Gamma Camera with a Parallel Plate Collimator for Tc-99m Imaging

A. Uritani, N. H. Clinthorne, J. E. Gormley, J. W. LeBlanc, W. L. Rogers, D. K. Wehe, S. J. Wilderman

Nuclear Science Symposium Conference Record, 1996 IEEE Vol. 1 page： 287 - 291 1996.10

Language：English

We present a new idea to apply a parallel plate collimator to an electronically-collimated gamma camera, to reduce the complexity of image reconstruction. Back projected images obtained experimentally and using Monte Carlo simulations are shown. Using the collimator, backprojected images of single low-energy gamma-ray emitters can be obtained with better spatial resolution and larger signal-to-noise ratio than those obtained without the collimator. The results show that this method is useful in obtaining Tc-99m images.

1-D Position Sensitive Single Carrier Semiconductor Detectors Reviewed

Z. He, G. F. Knoll, D. K. Wehe, R. Rojeski, C. H. Mastrangelo, M. Hammig, C. Barrett, A. Uritani

Nucl. Instr. and Methods Vol. A380 ( 1-2 ) page： 228-231 1996.10

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A single polarity charge sensing method has been studied using coplanar electrodes on 5 mm cubes of CdZnTe γ-ray detectors. This method can ameliorate the hole trapping problem of room-temperature semiconductor detectors. Our experimental results confirm that the energy resolution is dramatically improved compared with that obtained using the conventional readout method, but is still about an order of magnitude worse than the theoretical limit. A method to obtain the γ-ray interaction depth between the cathode and the anode is presented here. This technique could be used to correct for the electron trapping as a function of distance from the coplanar electrodes. Experimental results showed that a position resolution of about 0.9 mm FWHM at 122 keV can be obtained. These results will be of interest in the design of higher performance room-temperature semiconductor γ-ray detectors.

Radioactivity Distribution Measurement of Various Natural Material Surfaces with Imaging Plate Reviewed

C. Mori, T. Suzuki, S. Koido, A. Uritani, H.Miyahara, K. Yanagida, M. Yoshida and J. Miyahara

J. of Radioanalytical and Nucl. Chem. Vol. 206 ( 2 ) page： 263-268 1996.6

Improvement of Energy Resolution of CdTe Semiconductor Detector by Means of Digital Waveform Processing with Neural Network Algorithm Reviewed

H. Sakai, A. Uritani, K. Inoue, Y. Takenaka and C. Mori

J. of Radioanalytical and Nucl. Chem. Vol. 205 ( 1 ) page： 147-155 1996.4

Effect of Background Radiation Shielding on Natural Radioactivity Distribution Measurement with Imaging Plate" Reviewed

C. Mori, S. Koido, T. Suzuki, A. Uritani, H. Miyahara, K. Yanagida and J. Miyahara

Nucl. Instr. and Methods Vol. A369 ( 2-3 ) page： 544-546 1996.2

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Distribution images of natural radioactivity contained in various natural materials such as vegetable, animal meat and pottery work can be obtained with an imaging plate which has high sensitivity for nuclear radiations. For such very low levels of radioactivity, natural background radiations must be reduced using a shielding box. The lining, on the inside of the box, with low atomic number material such as acrylic resin is very effective in reducing electrons, β-rays and low energy X- and γ-rays emitted from the inner surface of the shielding material. Some images of natural radioactivity distribution were obtained and the radioactivity, mainly 40K, contained in natural materials was measured by using an HPGe detector and also the imaging plate itself.

Energy Resolution Enhancement of CdTe Semiconductor Detector Spectra by Using a Neural Network Algorithm Reviewed

Y. Takenaka, A. Uritani, K. Inoue, H. Sakai, O. Kubota, H. Toyokawa and C. Mori

Nucl. Instr. and Methods Vol. A369 ( 2-3 ) page： 637-641 1996.2

Use of Natural Radioactivity Distribution Images of Vegetables at Public Meetings Reviewed

C. Mori, S. Koido, T. Suzuki, H. Miyahara, A. Uritani, Y. Wu, K. Yanagida, M. Yoshida, F. Takahashi, J. Miyahara and K. Takahashi

Proc. 10th Pacific Basin Nuclear Conference ( 2 ) page： 921-925 1996

シンチレータ塗布・光ファイバーを用いた中性子束分布位置高分解能迅速測定法の開発（II）

三戸祐一郎、森千鶴夫、影山一巳、柳田勝男、瓜谷章、宮原洋、小林圭二、市原千博、代谷誠治、宇根崎博信、木村逸郎

京都大学原子炉実験所第３０回学術講演会報文集 page： 219-224 1996

シンチレータ塗布・光ファイバーを用いたγ線強度分布測定法の開発

影山一巳、森千鶴夫、三戸祐一郎、柳田勝男、瓜谷章、宮原洋、小林圭二、市原千博、代谷誠治、林正俊、宇根崎博信、木村逸郎

京都大学原子炉実験所第３０回学術講演会報文集 page： 225-228 1996

球形滅速材と位置検出型比例計数管を用いた多目的中性子測定器の開発

豊川弘之、瓜谷章、森千鶴夫

放射線 Vol. 21 ( 4 ) page： 52-58 1995.10

比例計数管と半導体検出器を組み合わせた速中性子エネルギースペクトロメーターの開発

東條匡志、森千鶴夫、瓜谷章、豊川弘之、工藤勝久、武田直人

放射線 Vol. 21 ( 4 ) page： 59-62 1995.10

A Multi-Purpose Spherical Neutron Counter Reviewed

H. Toyokawa, A. Uritani, C. Mori. N. Takeda and K. Kudo

IEEE Trans. on Nuclear Science Vol. NS-42 ( 4 ) page： 644-648 1995.8

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

We have developed a unique neutron counter applicable to measurements of fluence, energy distribution and the dose equivalent of neutrons with very wide energy range, and to estimations of incident direction of neutron beams. This 4π sensitive neutron counter consists of a spherical polyethylene moderator and three charge-division-type position-sensitive proportional counters (PSPCs) inserted into the moderator orthogonally with each other. The three PSPCs give thermal neutron distributions in the spherical moderator that bring us the above information. The characteristics of this neutron counter have been studied with Monte Carlo simulations and with experiments using monoenergetic neutrons.

Research for Application of Long Counter with a Position-Sensitive Proportional Counter to Neutron Dosimetry

Reactor Dosimetry Vol. STP1228 1995.8

A Long and Slender Position-Sensitive Helium-3 Proportional Counter with an Anode Wire Supported by a Ladder-Shaped Solid Insulator Reviewed

A. Uritani, Y. Kuniya, Y. Takenaka, H. Toyokawa, Y Yamane, C. Mori, K. Kobayashi, S. Shiroya and C. Ichihara

J. Nucl. Sci. Technol. Vol. 32 ( 8 ) page： 719-726 1995.8

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A long and slender position-sensitive 3He proportional counter with an outer diameter of 8mm and an effective length of 1.2m has been developed to measure neutron flux distributions in a critical assembly. Because it is difficult to make such a long and slender counter of con- ventional structure where an anode wire is stretched at the center of a cylindrical cathode tube, three prototype electrode systems of which anode wires are supported by insulator plates have been proposed. Among these three electrode systems, the electrode system of which anode wire is stuck on a ladder-shaped insulator has been adopted. The neutron flux distributions in the core of the Kyoto University Critical Assembly (KUCA) have been measured with the counter. Some non-uniformity of the detection efficiency has been observed throughout the counter. This non-uniformity has been corrected by calibrating the position-dependent detection efficiency with a gold wire activation method. A fairly satisfactory distribution, where the relative deviation from the gold wire activation method is 5.0%, has been obtained. Though the non-uniformity of the detection efficiency should be solved for precise measurements, the counter can be used for quick and rough measurements of neutron flux distributions.

Application of Digital Waveform Processing to Position-Sensitive Proportional Counter Reviewed

Y. Takenaka, A. Uritani and C. Mori

J. Nuclear Science and Technology Vol. 32 ( 4 ) page： 295-300 1995.4

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

In a charge-division type position-sensitive proportional counter (PSPC) with an anode wire of small resistance, a reflected component from an opposite end and thermal noise involved in signals deteriorate the position resolution of the PSPC. A digital waveform processing method was applied to the reduction of these undesirable effects by skillfully utilizing their signal characteristics that can be observed as inversely correlative signals between two-output signals from both sides of the PSPC. The digital waveform processing could improve the position resolution compared to a conventional pulse height processing method with analog filters. When the digital waveform processing was applied to signals of an equivalent circuit simulating the PSPC, the position resolutions defined by the full width at half maximum were improved to about 30% of those of conventional analog pulse processing. In the case of an actual PSPC, the position resolutions by the digital waveform processing were improved by 4-10% as compared with those of conventional pulse height processing.

中性子位置検出型核分裂計数管の開発

森千鶴夫、安藤彰浩、瓜谷章、羽賀剛

放射線 Vol. 21 ( 1 ) page： 35-42 1995.1

Characterization of Hexafluoroethane as Counting Gas of Position-Sensitive ³He Proportional Counter Reviewed

A. Uritani and C. Mori

Radioisotopes Vol. 44 ( 1 ) page： 23-27 1995.1

シンチレータ塗布・光ファイバーを用いた中性子束分布・位置高分解能迅速測定法の開発

森千鶴夫、三戸祐一郎、柳田勝男、影山一巳、国谷浩、瓜谷章、宮原洋、山根義宏、三澤毅、小林圭二、市原千博、代谷誠治、林正俊、宇根崎博信

京都大学原子炉実験所第２９回学術講演会報文集 page： 193-198 1995

Reduction of Microphonic Noise with Digital Waveform Processing Reviewed

A. Uritani, O. Kubota Y Takenaka and C. Mori

Nuclear Instruments and Methods Vol. A351 ( 2-3 ) page： 598-599 1994.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

This paper describes a new method of microphonic noise reduction by digital waveform processing. This method predicts the microphonic noise shape over the duration of a detector signal by making full use of the periodicity of the noise, and then removes the microphonic noise component from the detector signal. Preliminary experimental results that prove the validity of this method are presented.

Reduction of Digital Errors of Digital Charge Division Type position Sensitive Proportional Counter Reviewed

A. Uritani, K. Yoshimura, Y. Takenaka and C. Mori

Nuclear Instruments and Methods Vol. A353 ( 1-3 ) page： 246-250 1994.12

Measurement of Radioactivity Distribution of Material Surfaces with Imaging Plate Reviewed

C. Mori, T. Suzuki, S. Koido, H. Miyahara, A. Uritani, T. Aoyama and K. Nishizawa

Nuclear Instruments and Methods Vol. A353 ( 1-3 ) page： 371-374 1994.12

Dependence of Position Signal on Pressure of Counting Gas in Charge Division Type Position-Sensitive Proportional Counter Reviewed

Y. Wu, C. Mori, A. Uritani, H. Miyahara, K. Yanagida and M. Yoshida

J. Nuclear Science and Technology Vol. 31 ( 11 ) page： 1194-1201 1994.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

In the absolute radioactivity measurement of radioisotope gaseous samples with newly developed position-sensitive proportional counter (PSPC) method, it is necessary to change the counting gas pressure for the correction of the wall effect. The position signal was found to drift depending on the pressure. Theoretical explanation was given for this drift. Rise time of output pulses varies with gas pressure, which leads to a change of ballistic deficit. Consequently, the ballistic deficit differs between pulses from both the ends of the PSPC, which causes the change of position signals. Increasing the pressure of the counting gas from 0.5×105Pa to 4×105Pa, the range of position signals for two position calibration sources became narrower by about 8% under 6μs shaping time.

Reduction of Microphonic Noise by Digital Waveform Processing

A. Uritani, O. Kubota, Y. Takenaka, C. Mori

Nuclear Science Symposium Conference Record, 1994 IEEE Vol. 1 page： 905 - 909 1994.10

A Multipurpose Spherical Neutron Counter

H. Toyokawa, A. Uritani, C. Mori, N. Takeda, K. Kudo

Nuclear Science Symposium Conference Record, 1994 IEEE Vol. 1 page： 968 - 972 1994.10

Language：English

We have developed a unique neutron counter applicable to measurements of fluence, energy distribution and the dose equivalent of neutrons with a very wide energy range, and to estimations of the incident direction of neutron beams. This 4π sensitive neutron counter consists of a spherical polyethylene moderator and three charge-division-type position-sensitive proportional counters (PSPCs) inserted into the moderator orthogonally with each other. The three PSPCs give thermal neutron distributions in the spherical moderator that bring us the above information. The characteristics of this neutron counter have been studied with Monte Carlo simulations and with experiments using monoenergetic neutrons.

A Study on Position Resolution of Position-Sensitive ³He Proportional Counter Reviewed

A. Uritani, N. Marnada, Y. Takenaka, C. Mori and H. Miyahara

Nuclear Instruments and Methods Vol. A350 ( 1-2 ) page： 286-290 1994.10

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

The influences of wall effects and saturation of the gas multiplication on position resolutions of position-sensitive 3He proportional counters have been studied by means of numerical calculations, computer simulations and experiments. When the proton produced by the 3He(n,p)t reaction loses its specific energy in a counter wall by wall effects, a good position resolution is obtained escaping from any effects of a finite range of the proton and the triton. In the case where the gas multiplication is saturated, the best position resolution is obtained by selecting low pulse height events that the protons and the tritons move perpendicularly to the anode wire.

Optimization of Counting Time in the Radioactivity Measurement of Gaseous Samples with Inner Counting Method Reviewed

Y. Wu, C. Mori, A. Uritani, K. Yanagida, H. Miyahara, T. Aoyama and M. Yoshida

Nuclear Instruments and Methods Vol. A343 ( 2-3 ) page： 539-544 1994.4

Simple and Quick Measurement of Neutron Flux Distribution by Using an Optical Fiber with Scintillator Reviewed

C. Mori, T. Osada, K. Yanagida, T. Aoyama, A. Uritani, H. Miyahara, Y. Yamane, K. Kobayashi, C. Ichihara and S. Shiroya

J. Nuclear Science and Technology Vol. 31 ( 3 ) page： 248-249 1994.3

Analytical Calculations on Radioactivity Measurements of ¹⁹²Ir-Metallic Sources with a Calibrated Ionization Chamber Reviewed

A. Uritani, T Genka, C. Mori and D. F. G. Reher

Nuclear Instruments and Methods Vol. A339 ( 1-2 ) page： 377-380 1994.1

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

The self-attenuation of photons was analytically calculated for an 192Ir metallic wire source and an aqueous standard source. The influence of the self-attenuation on the current of the calibrated ionization chamber was also evaluated. The self-attenuation did considerably affect the ionization current. It was concluded that the apparent radioactivity must be multiplied by a correction factor larger than unity (1.09±0.01 in the present case) to get the true radioactivity when the radioactivity of the 192Ir metallic wire source was measured with the ionization chamber calibrated with the aqueous standard source of 192Ir.

Radioactivity Measurement of ¹⁹²Ir Wire Sources with a Microcalorimeter Reviewed

T. Genka, S. Iwamoto, N. Takeuchi, A. Uritani and C. Mori

Nuclear Instruments and Methods Vol. A339 ( 1-2 ) page： 398-401 1994.1

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Radioactivities of metallic 192Ir sources are measured with a microcalorimeter nondestructively. In order to convert the complete decay energy evolved from the source into thermal energy, a tungsten block is used as radiation absorber. The sample sources measured are four thin wires of Ir/Pt alloy with dimensions of 0.1 mmø × 10 mm1, each coated by 0.1 mm thick platinum, giving the final diameter of 0.3 mmø. Overall uncertainty of the measurement for some 60 MBq activity is ±3.2%. Measurements of the wire sources with an ionisation chamber give smaller activities which are smaller by 10% than those from microcalorimetry mainly because of the autoattenuation effect.

Direct Measurement of Gaseous Activities by Diffusion-in Long Proportional Counter Method Reviewed

M. Yoshida, T. Yamamoto, Y. Wu, T. Aratani, A. Uritani

Nuclear Instruments & Methods Vol. A330 ( 1-2 ) page： 158-164 1993.6

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Direct measurement of gaseous activities by the diffusion-in long proportional counter method (DLPC method) was studied. The measuring time without end effect was estimated by observing the behavior of 37Ar in the counter and was long enough to carry out the accurate activity measurement. The correction for wall effect was also examined on the basis of the measured and calculated correction factors. Among the tested gases of methane, P10 gas and propane, P10 gas was made clear to be a suitable counting gas for the DLPC method because of good diffusion properties and small wall effect. This method is quite effective for standardization of gaseous activities used for tracer experiments and calibration works of radioactive gas monitoring instruments.

Application of Digital Waveform Processing to signals Acquired from Position-sensitive Detector

Vol. 19 ( 2 ) page： 33-40 1993.5

Fabrication and Characteristics of a High Pressure Tiny Pump for Gas Circulation in Radioactivity Measurement of Gaseous Samples Reviewed

Y. Wu, C. Mori, T. Yamamoto, K. Yanagida, A. Uritani, H. Miyahara, T Aoyama and M.

Radioisotopes Vol. 42 ( 4 ) page： 209-215 1993.4

中性子位置検出器

瓜谷章

Vol. 42 ( 9 ) page： 549-550 1993

Characteristics of a Position-Sensitive Fission Counter and Its Applications Reviewed

C. Mori, A. Uritani, A. Ando, T. Osada, Y. Kuniya, K. Kobayashi, S. Shiroya, C. Ichihara

Kyoto University Research Reactor Institute Progress Report page： 140-141 1993

Radioactivity Measurement of ⁸⁵Kr with Position -sensitive Proportional Counter Reviewed

C. Mori, T Yamamoto, T Suzuki, A. Uritani, K. Yanagida, Y. Wu, T. Watanabe and M. Yoshida

Nuclear Instrument & Methods Vol. A312 ( 1-2 ) page： 189-192 1992.2

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Direct radioactivity measurement of 85Kr is difficult with ionization chambers, since it emits high-energy β-rays (Eβmax = 667 keV) which results in a severe wall effect. Also with proportional counters, the end-effect must be taken into account. The position-sensitive proportional counter (PSPC) method which can eliminate the end-effect was applied to direct measurement of 85Kr radioactivity. In the measurement, logarithmic amplifiers were employed to clearly distinguish between β-ray signals and noise signals, and to eliminate digital error in the calculation of position information. The radioactivity of 85Kr was determined with ±0.80% standard deviation.

Characteristics of a Position-Sensitive Fission Counter and Its Applications Reviewed

C. Mori, A. Ando, A. Uritani, K. Yanagida, Y. Kuniya, C. Ichihara, S. Shiroya, K. Kobayashi

Kyoto University Research Reactor Institute Progress Report page： 138-139 1992

A New Position-sensitive Nuclear Fission Counter with a Convenient Read out Method for Neutron Measurement Reviewed

C. Mori, T Haga and A. Uritani

Nuclear Instrument & Methods Vol. A310 ( 1-2 ) page： 437-440 1991.12

Measurement of Neutron Flux Distribution in Critical Assembly with Position-Sensitive Helium-3 Proportional Counter Reviewed

A. Uritani, C. Mori, T Haga, K. Yanagida N. Marnada, K. Kobayashi, S. Shiroya and C. Ichihara

J. Nuclear Science and Technology Vol. 28 ( 9 ) page： 824-830 1991.9

Highly Reliable Low-level Neutron Detection Using ³He Proportional Counters Reviewed

T. Aoyama, C. Mori, A. Uritani, T. Matsui and K. Naito

Radioisotopes Vol. 40 ( 5 ) page： 189-192 1991.5

Novel Position -sensing Method Using Fast and Slow components in the Output Signal from a Proportional counter Reviewed

A. Uritani, C. Mori, T Watanabe and A. Miyahara

Nuclea Instrument & Methods Vol. A299 ( 1-3 ) page： 231-233 1990.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

We have developed a novel position-sensing method of a proportional counter using slow and fast components in the output signal observed at one end of a resistive anode wire of which the other end is grounded through a capacitor. This paper describes the principle of the position sensing and some experimental results. Fairly sufficient characteristics in position resolution and integral linearity were obtained. This method will extend the application field of position-sensitive detectors.

Application of a Logarithmic Amplifier to a Charge-Division-Type Position-sensitive Proportional Counter Reviewed

C. Mori, T Suzuki, A. Uritani, T Yamamoto, K. Yanagida, T Watanabe and M. Yoshida

Nuclear Instrument & Methods Vol. A299 ( 1-3 ) page： 128-132 1990.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Fulfillment of both observation of pulses ranging from about 10 mV to 10 V through ADC and carrying out an arithmetic calculation with small digital errors for such digitized pulses is usually difficult, although it is required in measurements using a charge-division-type position-sensitive proportional counter (PSPC). However, the use of a logarithmic pulse amplifier sometimes solves this problem. The advantage of using a logarithmic pulse amplifier is described through the application of the amplifier to absolute-radioactivity measurements of gaseous samples and to the simultaneous measurement of geometrical distributions of neutrons and gamma-rays with the PSPC.

Novel Position Sensing Method Using Fast and Slow Components in an Output Signal from a Proportional Counter Reviewed

A. Uritani and C. Mori

Nuclear Instruments and Methods Vol. A294 ( 3 ) page： 677-678 1990.9

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

We propose a novel position-sensing method using slow and fast components in an output signal observed at one end of a resistive anode wire in a proportional counter in which the other end of the anode wire was grounded through a capacitor. Fairly sufficient characteristics in position resolution and an integral linearity were obtained. This method will extend the application field of a position-sensitive detector.

Development of Position-Sensitive Helium-3 Proportional Counter for Thermal Neutrons with Novel Signal Readout Reviewed

A. Uritani, C. Mori, T Watanabe and A. Miyahara

J. Nuclear Science & Technology Vol. 27 ( 8 ) page： 712-717 1990.8

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A position sensitive 3He proportional counter for thermal neutrons with a novel signal readout method which has two pre-amplifiers at only one end of the counter body has been developed. It has an advantage for usage in a special environment, such as in a subcritical facility or in water, or for insertion into a narrow space. The characteristics of the counter were evaluated with thermal neutrons. The position resolution was 7 mm with an effective length of 1, 200 mm. The integral non-linearity of position signal was less than 0.5%.

熱中性子用位置検出型比例計数管の開発

瓜谷章、森千鶴夫

放射線 Vol. 16 ( 2 ) page： 80-91 1990.3

Improvement of Signal Readout in Charge Division Type Position Sensitive Proportional Counter Reviewed

A. Uritani, C. Mori, T Watanabe and A. Miyahara

J. Nuclear Science & Technology Vol. 26 ( 12 ) page： 1094-1101 1989.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

It is generally difficult to insert a position sensitive proportional counter (PSPC) with a conventional charge division in a narrow space, or to work the counter under special environments, such as in water or in a reactor. We improved the position signal readout to make it possible to use a PSPC under such environments. A position signal was extracted from only one end of an anode wire by grounding the other end through a capacitor and a total charge signal was obtained from twelve cathode wires stretched parallel to the anode wire, so that two pre-amplifiers were able to be connected at only one end of the counter. The character-istics of the PSPC with the improved signal readout were examined with X-rays. The position resolution was 1.3 mm with an effective length of 550 mm, and depended on the X-ray injection position. A non-linearity of position signals was less than 0.2%.

Multi element Position Sensitive Proportional Counter for Measurement of Tritium Labeled Gas Movement Reviewed

C. Mori, A. Uritani and T. Watanabe

J. Nuclear Science and Technology Vol. 25 ( 4 ) page： 341-349 1988.4

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A multielement position sensitive proportional counter was developed for the measurement of 3H labeled gas movement in a pipe by internal counting. The counter consists of an outer cylindrical pipe with an inner diameter of 40 mm, seven resistive stainless steel anode wires with a diameter of 22μm, and 24 cathode wires with a diameter of 120μm. These wires divide the radial cross section of the pipe into seven regions. Since each region independently works as a position sensitive proportional counter and the seven resistive anode wires are connected in series through lump resistors, the region and the axial position where a β-decay event occurred can be known by a simple operation upon the charge signals obtained from two preamplifiers. The axial position resolution for 3H β-rays was 9 mm FWHM. Demonstrative experiments were performed for the flow and diffusion of 3H labeled ethane in the counter pipe.

Charge Transfer Process and Sputtering Process of Self-sustaining alkali Metal Coating on Metal Surface Reviewed

A. R. Krauss, O. Auciello, A. Uritani, M. Valentine, R. Mendelsohn and D. M. Gruen

Nuclear Instrument & Methods Vol. B27 ( 1 ) page： 209-220 1987.6

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

It is well known that adsorption of electronegative or electropositive atoms on a metal surface results in charge transfer between the metal conduction band and the adsorbate atom. This charge transfer results in the formation of a coverage-dependent image dipole and a consequent change in the work function and adsorbate binding energy. Additionally, the secondary electron yield and the charge state of surface atoms desorbed by thermal, electron impact or ion impact desorption processes are closely related to the effective adsorbate charge.

We discuss here the effect of Gibbsian segregation as a means of producing similar effects for electropositive (alkali metal) layers on a number of metal substrates. Classical chemisorption theory is used as a means of estimating the adsorbate effective charge and the results are compared with models used to predict the secondary ion fraction of sputtered atoms. The resulting concept of self-sustaining sputter-resistant coatings is analyzed in the context of applications to the fusion environment as well as to, e.g., materials for high current electrical contacts.

New Partial Pressure Gauge for Helium and Deuterium Using the Ion Backscattering Principle Reviewed

K. Akaishi, Y Kubota, A. Uritani and Y Hori

J. Vacuum Science and Technology Vol. A5 ( 4 ) page： 2444-2446 1987.6

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A new partial pressure gauge is proposed that is capable of measuring partial pressures of He and D2 gases in the mixture. The gauge consists of a conventional ion scattering spectrometer with a Wien filter. The influence of the residual gases CH4 and H2O on the pressure measurements of D2 and He in this gauge is discussed.

Implantation and Replacement of Hydrogen Isotopes Implanted in 304 Stainless Steel Vacuum Wall under RF Discharge and RF-DC Glow Discharge Reviewed

K. Akaishi, Y Kubota, A. Uritani and Y Hori

J. Nuclear Material Vol. 145-147 page： 275-279 1987.2

Conceptual Design and Engineering Aspect of Tokamak Burning Plasma Experiments -the R-projects, Chapter 5 Vacuum System

A. Uritani and K. Akaishi

Nuclear Engineering Design/Fusion Vol. 42 ( 2 ) page： 405-409 1987.1

R & D Efforts for the R-TOKAMAK Components

A. Miyahara, Y. Fujii-e, K. Kamada, Y. Oka, O. Kaneko, K. Sakurai, T. Kuroda, K.N.Sato, A. Uritani, K. Akaishi and H. Amano

Nuclear Engineering Design/Fusion Vol. 42 ( 2 ) page： 357 1987.1

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

In parallel to the conceptual design of the R-tokamak, research and development efforts on
the systems and the components have been carried out to obtain scopes to realize the device.
Because we intended to introduce DT fuels into the device, the items of research and
development works are quite different to that of non-burning machines. Alminium alloy
developments to avoid activations by 14 MeV neutron irradiations, tritium safe handling and
vacuum system with tritium are examples of this category. Beside specific requirement directly
caused by DT introduction, highly reliable operation of the machine is strongly requested,
because it is the necessary condition to perform experiments safely. However, these efforts are
still in an early stage of investigation and many efforts are needed to prepare a rigid data base
tokamak operation with reacting plasma.

高周波、直流グロー放電下における水素同位体の交換脱離

赤石憲也、久保田雄輔、瓜谷章、堀洋一郎

真空 Vol. 29 ( 5 ) page： 160-169 1986.5

A New Partial Pressure Gauge for He and D₂ Using Ion Backscattering Technique Reviewed

A. Uritani, K. Akaishi, Y. Kubota, Y. Hori and A. Miyahara

Japanese J. Applied Physics Vol. 25 ( 5 ) page： L403-L405 1986.5

イオン散乱法を用いた重水素、ヘリウム分圧の新らしい計測法

瓜谷章、赤石憲也、久保田雄輔、堀洋一郎

真空 Vol. 29 ( 5 ) page： 249-252 1986.5

イオン後方散乱法による重水素、ヘリウム分圧計測法

瓜谷章、赤石憲也、久保田雄輔、堀洋一郎、宮原昭

核融合研究 Vol. 55 ( 4 ) page： 360-370 1986.4

Charge Transfer Processes and Sputtering Processes of Self-Sustaining Alkali Metal Coating on Metal Surface

A.R.Krauss, O.Auciello, A.Uritani, M.Valentine, R.Mendelsohn and D.M.Gruen

US DOE Report Vol. 860807 ( 2 ) page： 43-53 1986.1

水素吸収におけるZr－V合金のISS観察

瓜谷章、赤石古也、久保田雄輔、堀洋一郎、壁谷善三郎、鈴木基行、蒲生孝治

真空 Vol. 28 ( 5 ) page： 317-320 1985.5

ポリイミドの水素透過係数の測定

瓜谷章、赤石憲也、小川雄一、日野利彦、勝村広

真空 Vol. 28 ( 5 ) page： 321-323 1985.5

Position-Sensitive Proportional Counter for Measurement of Tritium Labelled Gas Movement Reviewed

C. Mori, M. Nakamoto, A. Uritani and T Watanabe

J. Nuclear Science & Technology Vol. 21 ( 12 ) page： 942-948 1984.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

A position sensitive proportional counter of a charge division type with a single resistive anode wire was constructed for the measurement of the movement of 3H labelled gas which is flowing or diffusing in a pipe. The introduction of resistors between the anode wire and pre-amplifiers brought a uniform detection efficiency for 3Hβ-rays throughout the counter. The position resolution was 3.1 mm FWHM. Detection efficiency was almost 100% uniformly over about 700 mm in the total anode length of 740 mm. The movement of 3H labelled gas could be measured effectively.

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