Mar. 2015, 北海道大学, 教育総長賞・奨励賞　　　　　　　　　　　　　　　
金子純一

Mar. 2015, 北海道大学, 研究総長賞 優秀賞　　　　　　　　　　　　　　　
金子純一

Mar. 2014, 北海道大学, 研究総長賞　　　　　　　　　　　　　　　
金子純一

Mar. 2012, 日本原子力研究開発機構, 先行基礎工学研究協力制度 表彰　　　　　　　　　　　　　　　
GPS高エネルギー分解能シンチレータによる高信頼性α線波高弁別検出器の開発
金子純一

2008, 文部科学省, 先進的原子力･エネルギー教育取組、「教育支援活動」優秀賞　　　　　　　　　　　　　　　
住吉 孝、奈良林 直、金子純一

Measurement of Neutrons Produced by Inertial Fusion with a Diamond Radiation Detector
Takehiro Shimaoka, Junichi H. Kaneko, Yasunobu Arikawa, Mitsutaka Isobe,Masakatsu Tsubota, Kengo Oda, Mitsuo Nakai, Hiroyuki Shiraga,Hiroshi Azechi, Akiyoshi Chayahara, Hitoshi Umezawa, Shinichi Shikata
Sensors and Materials, 36, 1, 217, 217, MYU K.K., 26 Jan. 2024
Scientific journal

Energy Spectroscopy for Low-energy Photons Using Diamond Detector Combined with Micro-CMOS Preamplifier
Kengo Oda, Junichi H. Kaneko, Daisuke Matsunaga, Takanori Hanada, Tsukasa Mizukoshi, Shintaro Hirano
Sensors and Materials, 36, 1, 251, 251, MYU K.K., 26 Jan. 2024
Scientific journal

Development of a large-area alpha imaging detector for hand and foot monitors
Yuki Morishita, Mikio Higuchi, Junichi H. Kaneko, Yuichi Kitagawa, Jun Akedo, Mitsugu Sohma, Hiroaki Matsui
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1057, 168702, 168702, Elsevier BV, Dec. 2023
Scientific journal

Irradiation effects of X-rays up to 3 MGy on hydrogen-terminated diamond MOSFETs
Tadashi Masumura, Hitoshi Umezawa, Takahiro Yamaguchi, Yusei Deguchi, Hiroyuki Kawashima, Toshiharu Makino, Naohisa Hoshikawa, Hitoshi Koizumi, Junichi H. Kaneko
Diamond and Related Materials, 135, 109825, 109825, Elsevier BV, May 2023
Scientific journal

Radiation effect of X-ray with 1 kGy dose on the electrical properties of MESFET based on hydrogen-terminated diamond surface conductivity
Mingchao Yang, Takehiro Shimaoka, Liwen Sang, Junichi H. Kaneko, Satoshi Koizumi, Meiyong Liao
FUNCTIONAL DIAMOND, 2, 1, 40, 45, Apr. 2022, [Peer-reviewed]
English, Scientific journal

Radiation hardened H-diamond MOSFET (RADDFET) operating after 1 MGy irradiation
Takahiro Yamaguchi, Hitoshi Umezawa, Shinya Ohmagari, Hitoshi Koizumi, Junichi H. Kaneko
APPLIED PHYSICS LETTERS, 118, 16, AMER INST PHYSICS, Apr. 2021, [Peer-reviewed], [Last author]
English, Scientific journal, Although the surface conductivity of a hydrogen-terminated diamond (H-diamond) enables production of high-performance field effect transistors (FETs), the total ionizing dose effect is yet to be clarified for H-diamond FETs. We fabricated a RADiation hardened H-terminated Diamond metal-oxide-semiconductor FET (RADDFET) using an oxide gate dielectric deposited at high temperatures. This paper describes its stable operation after 1 MGy irradiation. H-diamond films were prepared using microwave plasma assisted chemical vapor deposition with a p+ layer for reduction of contact resistance. The Al2O3 passivation layer was deposited by atomic layer deposition at 450 degrees C to achieve operation in high-temperature environment; then a RADDFET was fabricated on them using a Ru electrode. Several current-voltage characteristics were compared before irradiation and after certain dose levels up to 1 MGy. Before they were irradiated in air, the dose rate was measured using a cellulose triacetate film dosimeter. Even after an irradiation level of 1 MGy, the off-current at gate bias voltage (V-G) of 3V was more than six orders of magnitude lower than the on-current at V-G of -6V. Variation of the drain current density (J(DS)) in the measurements was less than 2%. The threshold voltage shifted approximately 1.7V with 3 kGy of x ray irradiation, but no marked degradation was confirmed at higher levels. The subthreshold swings were 238, 215, and 264mV/decade, respectively, after irradiation of 100 kGy, 300 kGy, and 1 MGy. These results indicate that the RADDFET was very stable at higher doses after initial stabilization.

High yield uniformity in pseudo-vertical diamond Schottky barrier diodes fabricated on half-inch single-crystal wafers
Takanori Hanada, Shinya Ohmagari, Junichi H. Kaneko, Hitoshi Umezawa
APPLIED PHYSICS LETTERS, 117, 26, AMER INST PHYSICS, Dec. 2020, [Peer-reviewed]
English, Scientific journal, We fabricated diamond pseudo-vertical Schottky barrier diodes using a half-inch semi-insulative diamond (100) wafer. Most diodes exhibited a large rectifying ratio (>10(10)) with undetectable leakage current at a reverse bias of 5V (0.6MV cm(-1)), with only 2% of diodes exhibiting an Ohmic-like leakage current. Surface defects were observed under the Schottky barrier diode, and their impacts on electrical properties were analyzed using a Murphy model and correlation factor analysis. We found that most crystalline defects (surface hillocks) were electrically non-active and that non-epitaxial crystallites and process-related field-plate cracks were the main defects that induced a large leakage current. Schottky barrier diodes without such killer defects showed a high electric field strength of similar to 5MV cm(-1).

Development of a Gd2Si2O7 (GPS) Scintillator-Based Alpha Imaging Detector for Rapid Plutonium Detection in High-Radon Environments
Yuki Morishita, Kenji Izaki, Junichi H. Kaneko, Seiichi Yamamoto, Mikio Higuchi, Tatsuo Torii
IEEE TRANSACTIONS ON NUCLEAR SCIENCE, 67, 10, 2203, 2208, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Oct. 2020, [Peer-reviewed]
English, Scientific journal, We developed a Gd2Si2O7 (GPS) scintillator-based alpha imaging detector and demonstrated its effectiveness by evaluating the actual Pu particle and Rn-222 progeny. The GPS scintillator plate was prepared by a sintering method. The outer dimensions of the GPS scintillator plate were 5 x 5 cm, and the scintillator layer was approximately 50 mu m on a 3-mmthick high-transparency glass. The plate was optically coupled to a position-sensitive photomultiplier tube (Hamamatsu H8500, Hamamatsu, Japan) with silicone grease. The developed imaging detector exhibited good uniformity; Pu particle activities were accurately evaluated at 14 different positions and the difference in activity was within +/- 6%. The radon-222 progeny counts were reduced by 65.3% by applying an energy window. Although the Pu/Rn-222 progeny activity ratio was 1/51, the Pu particle was successfully identified among the Rn-222 progeny within the 5-min measurement time. The imaging detector has an excellent ability for detecting Pu among the Rn-222 progeny. Thus, this detector is useful for alpha contamination monitoring in high-radon-background environments.

Heat and radiation resistances of diamond semiconductor in gamma-ray detection
Katsunori Ueno, Takahiro Tadokoro, Yuichiro Ueno, Keisuke Sasaki, Satoshi Koizumi, Akiyoshi Chayahara, Yoshiaki Mokuno, Shintaro Hirano, Junichi H. Kaneko
JAPANESE JOURNAL OF APPLIED PHYSICS, 58, 10, IOP PUBLISHING LTD, Oct. 2019, [Peer-reviewed], [Last author]
English, Scientific journal, We have developed a gamma-ray detector based on a single-crystal diamond in order to improve the heat and radiation resistances of gamma-ray monitors. We fabricated prototypes with two types of diamond grown by a chemical vapor deposition method. The count rates with temperature and accumulated dose were obtained using a Cs-137 gamma-ray source, then the errors at full scale (%FS) were evaluated using a method to reduce the dark count. The prototype-A worked to 643 K within 2.9%FS and to 3.1 MGy within 4.9%FS; on the other hand, the prototype-B worked to 545 K within 3.4%FS and to 5.0 MGy within 0.47%FS. This study demonstrates that the diamond semiconductor was promising for monitoring with enhanced heat and radiation resistances. (C) 2019 The Japan Society of Applied Physics

Development of an alpha dust monitor using a GPS scintillator plate
Morishita, Y, Kaneko, J.H, Higuchi, M, Izaki, K, Yajima, T, Matsuura, M, Tamura, K, Torii, T
Radit. Meas., 122, 115, 120, PERGAMON-ELSEVIER SCIENCE LTD, Mar. 2019, [Peer-reviewed]
English, Scientific journal, A dust monitor with a silicon surface barrier detector (SSBD) is introduced at a nuclear fuel facility to detect airborne contamination of Pu-238 and (PU)-P-239 released by past accidents. However, an SSBD frequently produces false alarms, especially in a room with high humidity. To develop a highly reliable dust monitor, we developed an alpha-particle spectrometer based on a cerium-doped Gd2Si2O7 (GPS) scintillator plate and a photomultiplier tube (PMT). The GPS scintillator plate is hexagonal and 50 mm in diameter, and the scintillator layer is approximately 40 mu m. An output signal from the PMT is amplified by a preamp and transferred to an MCA. Then, an energy spectrum is displayed in real time. The (241)AM alpha source, Rn progeny collected on the air filter, and a PuO2 particle were measured by our developed spectrometer. The energy resolution for 5.5-MeV alpha particles was similar to 11.9% +/- 0.2% of the FWHM. The efficiency was 92%, and it had a uniform sensitivity. By applying an energy window, the count-rate of the Rn progeny decreased by 77%. The GPS scintillator plate was able to measure the alpha spectrum even though the GPS scintillator got wet. Therefore, the alpha dust monitor using the GPS scintillator plate is ideal for detecting alpha-particle emitters in places lacking temperature and humidity controls, such as the outside of buildings.

Substrate Effects on Charge Carrier Transport Properties of Single-Crystal CVD Diamonds and an 8 mm Square Radiation Energy Spectrometer
Shintaro Hirano, Junichi H. Kaneko, Takanori Hanada, Shogo Ito, Takehiro Shimaoka, Hiroaki Shimmyo, Masakatsu Tsubota, Akiyoshi Chayahara, Yoshiaki Mokuno, Hitoshi Umezawa
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, 215, 22, WILEY-V C H VERLAG GMBH, Nov. 2018, [Peer-reviewed]
English, Scientific journal, In an effort to enlarge a sensitive area of a diamond radiation energy spectrometer, a self-standing chemical vapor deposition (CVD) single crystal is grown on an 8-mm-square "general grade" CVD single-crystal diamond substrate fabricated by Element Six Ltd. The growth conditions that achieved a mu tau product of 3 x 10(-4) cm(2) V-1 for holes in a CVD single-crystal diamond grown on a high-pressure and high-temperature (HP/HT) type IIa single-crystal diamond substrate elsewhere are adopted. The charge collection efficiency (CCE) of 99.9% for both charge carriers, and 0.39% and 0.5% of energy resolution for holes and electrons are achieved using 5.486 MeV alpha particles. Uniformity of the energy resolution is sufficient for the use of a radiation energy spectrometer. However, mu tau products of (5.0 +/- 0.4) x 10(-5) and (1.8 +/- 0.2) x 10(-5) cm(2) V-1 for holes and electrons are obtained, respectively. These values are approximately one order of magnitude smaller than the mu tau products of the CVD single crystal grown on a HP/HT type IIa diamond substrate using the same growth conditions.

Optimization of thickness of GAGG scintillator for detecting an alpha particle emitter in a field of high beta and gamma background
Morishita Yuki, Yamamoto Seiichi, Izaki Kenji, Kaneko Junichi H, Hoshi Katsuya, Torii Tatsuo
RADIATION MEASUREMENTS, 112, 1, 5, PERGAMON-ELSEVIER SCIENCE LTD, May 2018, [Peer-reviewed]
English, Scientific journal, At the site of the Fukushima Daiichi nuclear power plant (FDNPP), there is a large quantity of beta and gamma emitters such as Sr-90 and Cs-137. Moreover, radon (Rn) progeny, which are naturally occurring radionuclides, exist and emit alpha and beta particles. To detect plutonium isotopes ((PU)-P-238, (PU)-P-239, and Pu-240) in a field of high beta and gamma background, an alpha particle detector with low beta- and gamma-ray sensitivity and good energy resolution for an alpha particle is required to distinguish plutonium isotopes from Rn progeny. Previously, we developed an alpha particle imaging detector by combining a 0.1-mm-thick gadolinium aluminum gallium garnet (GAGG) scintillator with a silicon photomultiplier (SiPM). However, this detector was sensitive to environmental gamma and beta rays. In this study, we optimized the thickness of the GAGG scintillator for alpha particle detection in a field of high beta and gamma background. We prepared three GAGG scintillators with thicknesses of 0.05 mm, 0.07 mm, and 0.1 mm. Each of the GAGG scintillators was coupled optically to the SiPM array, which was used as the photodetector. Alpha, beta, and gamma rays were irradiated onto the developed alpha particle detector, and their spectra were obtained. The energy resolution of the 0.05 mm-thick GAGG for 5.5-MeV alpha particles (similar to 11.6% full width at half maximum [FWHM]) was the best among the three GAGG scintillators. All GAGG scintillators used in this study were not sensitive to gamma rays with a dose rate of 1 mSv/h. The beta particle count above the lower level discriminator (LLD) decreased because the scintillator was thinner, and the beta count of the 0.05-nun-thick GAGG was only 1/100 that of the 0.1-mm-thick GAGG. Because the alpha particle detector with the 0.05-mm-thick GAGG scintillator had low beta and gamma ray sensitivity and good energy resolution for alpha particles, it is promising from the viewpoint of detecting plutonium contamination in a field with high beta and gamma background, such as the FDNPP site.

DEVELOPMENT OF A NEW DETECTOR SYSTEM TO EVALUATE POSITION AND ACTIVITY OF PLUTONIUM PARTICLES IN NASAL CAVITIES
Yuki Morishita, Seiichi Yamamoto, Takumaro Momose, Junichi H. Kaneko, Norio Nemoto
RADIATION PROTECTION DOSIMETRY, 178, 4, 414, 421, OXFORD UNIV PRESS, Mar. 2018, [Peer-reviewed]
English, Scientific journal, Plutonium dioxide (PuO2) is used to fabricate a mixed oxide fuel for fast breeder reactors. When a glove box containing PuO2 fails, such as by rupture of a glove or a vinyl bag, airborne contamination of plutonium (Pu) can occur. If a worker inhales PuO2 particles, they will be continually irradiating their lung tissue with alpha particles, and this could cause lung cancer. The nasal smear and nose blow methods are useful for checking workers for PuO2 intake in the field. However, neither method can evaluate the quantitative activity of Pu. No alpha-particle detector that can be used for direct measurements in the nasal cavity has been developed. For direct and quantitative measurement, it is required that a shape of the detector should be a fine bar which inserts itself in the nose to measure the accurate activity of Pu. Therefore, we developed a nasal monitor capable of directly measuring the activity of Pu in the nasal cavity to estimate the internal exposure dose of a worker. Prismatic-shaped 2 x 2 acrylic light guides were used to compose a detector block, and a ZnS(Ag) scintillator was adhered to the surface of these light guides. Silicon photomultiplier (SiPM) arrays with 8 x 8 channels were used as a photodetector. Actual PuO2 particles were measured using the nasal monitor. The nasal monitor could be directly inserted in the nasal cavities, and the activity distribution of Pu was obtained by the nasal monitor. The average efficiencies in 4-pi were 11.4 and 11.6% for the left and right nasal cavities, respectively. The influence of gamma and beta rays from Cesium-137 (Cs-137) Strontium-90 (Sr-90) on the detection of the alpha particles of Pu was negligible. The difference in the measured Pu activity between the ZnS(Ag) scintillation counter and the nasal monitor was within 4.0%. Therefore, it was considered that the developed nasal monitor could be used in direct Pu determination to estimate the internal exposure dose of workers.

Diamond semiconductor-based gamma-ray detector for a severe environment
Katsunori Ueno, Keisuke Sasaki, Junichi Kaneko
Transactions of the American Nuclear Society, 119, 534, 536, 2018, [Peer-reviewed]
International conference proceedings

Flexible alpha camera for detecting plutonium contamination
Yuki Morishita, Seiichi Yamamoto, Kenji Izaki, Junichi H. Kaneko, Norio Nemoto
RADIATION MEASUREMENTS, 103, 33, 38, PERGAMON-ELSEVIER SCIENCE LTD, Aug. 2017, [Peer-reviewed]
English, Scientific journal, We developed a new imaging detector called flexible alpha camera that can identify Pu contamination in narrow spaces at work sites. The thickness of the flexible alpha camera is only similar to 1/5th that of the ZnS(Ag) scintillation detector which is commonly used for detecting Pu contamination, and its efficiency in the 4 pi direction is 42.7% for 5.5-MeV alpha particles. The minimal detectable activity (MDA) is 0.014 Bq measured in 30 min. Four types of PuO2 samples, taken from a duct, bag-in/bag-out port, glovebox glove, and vinyl sheet, were measured by the flexible alpha camera. In a two-dimensional distribution of alpha particles, PuO2 was identified automatically using the "AnalyzeParticle" function in the ImageJ plugin, and its activity was evaluated. When acquisition time increased from 10 min to 30 min, a Pu spot with low activity was identified. To verify the measurement in narrow space, a fume hood to which a PuO2 particle was attached was measured using the flexible alpha camera. Since the flexible alpha camera has the thin-thickness of 12 mm and can obtain two-dimensional distribution and energy spectrum of alpha particles, it is effective for detecting Pu contamination in narrow spaces of equipment. (C) 2017 Elsevier Ltd. All rights reserved.

Characterization of X-ray radiation hardness of diamond Schottky barrier diode and metal-semiconductor field-effect transistor
Hitoshi Umezawa, Shinya Ohmagari, Yoshiaki Mokuno, Junichi H. Kaneko
Proceedings of the International Symposium on Power Semiconductor Devices and ICs, 379, 382, 2017, [Peer-reviewed]
International conference proceedings, Diamond has attracted extensive attention for the next generation semiconductor devices, such as high-power, low-loss and high-frequency devices under high temperature conditions. In this paper, a radiation hardness of diamond unipolar devices such as Schottky barrier diode (SBD) and metal-semiconductor field-effect transistor (MESFET) was discussed. No any degradation of ideality factor or specific on-resistance of diamond SBD was observed even after 10 MGy X-ray irradiation. The breakdown voltage was increased after the irradiation since the leakage current increased. The forward current capability and the transconductance of MESFET were almost constant to the X-ray irradiation.

Preparation and scintillation properties of translucent LiCaBO3:Ce polycrystalline plates
Toyoda S, Higuchi M, Tsubota Y, Kaneko J. H, Tadanaga K
Optical Materials, 70, 180, 183, ELSEVIER SCIENCE BV, 2017, [Peer-reviewed]
English, Scientific journal, Translucent LiCaBO3:Ce thin plates were prepared by liquid phase sintering using LiBO2 as a sintering aid, and their fluorescent and scintillation properties were investigated to examine the possibility to use as neutron scintillator. Since the initial part of the directionally solidified specimen contained a second phase of Ca3B2O6, LiCaBO3 may melt incongruently, and simple melt growth of LiCaBO3:Ce is consequently difficult. Translucent thin plates 300 mu m in thickness were successfully fabricated from LiCaBO3:Ce sintered compacts. Although strong fluorescence with the peak wavelength of 390 nm was observed in photoluminescence measurement, scintillation light yield and detection efficiency by alpha-particle irradiation were rather poor. The diffuse reflectance spectrum of LiCaBO3:Ce revealed existence of an absorption band other than Ce3+ bands in the ultraviolet region. The band may corresponds to defect levels, which interrupt the energy transfer from the conduction band of the host to the 5d level of Ce3+ resulting in the degradation of the scintillation performance. (C) 2017 Elsevier B.V. All rights reserved.

An alpha particle detector based on a GPS mosaic scintillator plate for continuous air monitoring in plutonium handling facilities
Junichi H. Kaneko, Kenji Izaki, Kouhei Toui, Takehiro Shimaoka, Yuki Morishita, Youichi Tsubota, Mikio Higuchi
RADIATION MEASUREMENTS, 93, 13, 19, PERGAMON-ELSEVIER SCIENCE LTD, Oct. 2016, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal, An alpha particle detector was developed for continuous air monitoring of radioactive contamination in working chambers at plutonium handling facilities. A 5-cm-square Gd2Si2O7:Ce (cerium-doped gadolinium pyro-silicate, GPS:Ce) mosaic scintillator plate for alpha particle measurements was fabricated from GPS single-crystal grains of around 550 mu m diameter; the GPS grains were made of a GPS polycrystalline body grown using a top seeded solution method. The scintillator layer thickness was approximately 100 gm. The surface filling rate of the GPS grains was ca. 62%. To suppress the influence of non-uniformity of pulse heights of a photomultiplier tube, a central part of empty set 40 mm of a 76-mm diameter photomultiplier tube was used. In addition, 3 mm thick high-transmission glass was used as a substrate of the scintillator plate. The detector achieved energy resolution of 13% for 5.5 MeV alpha particles, detection efficiency of 61% and a radon progeny nuclide reduction ratio of 64.5%. A new alpha particle detector was developed to achieve a high radon progeny nuclide reduction ratio approaching that of a silicon semiconductor detector, with high resistance to electromagnetic noise and corrosion. (C) 2016 Elsevier Ltd. All rights reserved.

Charge-collection efficiency of single-crystal CVD diamond detector for low-energy charged particles with energies ranging from 100 keV to 2 MeV
Yuki Sato, Hiroyuki Murakami, Takehiro Shimaoka, Masakatsu Tsubota, Junichi H. Kaneko
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 834, 218, 222, ELSEVIER SCIENCE BV, Oct. 2016, [Peer-reviewed], [Last author]
English, Scientific journal, The performance of a diamond detector created from a single-crystal diamond grown by chemical vapor deposition was studied for application in detecting charged particles having energies ranging from 100 keV to 2 MeV. Energy peaks of different low-energy ions were clearly observed. However, we observed that the pulse height for individual incident ions decreases with increasing atomic number of the ions. We estimated the charge collection efficiency of the generated charge carriers by the incident charged particles. The charge collection efficiencies are 97.0 +/- 0.7% for 2 MeV helium-ions (He+). On the other hand, compared with that of He+, silicon-ions (Si+) and gold-ions (Au3+) show low charge collection efficiency: 70.6 +/- 2.2% and 29.5 +/- 4.2% for 2 MeV-Si+ and 2 MeV-Au3+, respectively. We also found that the charge collection efficiency decreases as the generated charge density inside the diamond crystal increases. (C) 2016 Elsevier B.V. All rights reserved.

Fano factor evaluation of diamond detectors for alpha particles
Takehiro Shimaoka, Junichi H. Kaneko, Yuki Sato, Masakatsu Tsubota, Hiroaki Shimmyo, Akiyoshi Chayahara, Hideyuki Watanabe, Hitoshi Umezawa, Yoshiaki Mokuno
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, 213, 10, 2629, 2633, WILEY-V C H VERLAG GMBH, Oct. 2016, [Peer-reviewed]
English, Scientific journal, This report is the first describing experimental evaluation of Fano factor for diamond detectors. High-quality self-standing chemical vapor deposited diamond samples were produced using lift-off method. Alpha-particle induced charge measurements were taken for three samples. A 13.1 +/- 0.07 eV of the average electron-hole pair creation energy and excellent energy resolution of approximately 0.3% were found for 5.486MeV alpha particles from an Am-241 radioactive source. The best Fano factor for 5.486MeV alpha particles, calculated from experimentally obtained epsilon values and the detector intrinsic energy resolution, was 0.382 +/- 0.007. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Charge-collection efficiency and long-term stability of single-crystal CVD diamond detector under different carrier-drift conditions
Yuki Sato, Hiroyuki Murakami, Takehiro Shimaoka, Masakatsu Tsubota, Junichi H. Kaneko
JAPANESE JOURNAL OF APPLIED PHYSICS, 55, 4, IOP PUBLISHING LTD, Apr. 2016, [Peer-reviewed], [Last author]
English, Scientific journal, We investigate the performance of a charged-particle detector fabricated using single-crystal diamond grown by chemical vapor deposition. The detector identified four different Am-241 alpha-particle energies (5.389, 5.443, 5.486, and 5.545 MeV) thanks to its superior energy resolution of 0.407 +/- 0.004% for electron drift and 0.418 +/- 0.004% for hole drift (full width at half maximum). The charge-collection efficiency inside the diamond crystal was above 97.0% for both electrons and holes. The diamond detector also exhibited no significant degradation in terms of pulse-height spectra and energy resolution during operation for more than 100 h under electron-drift conditions. In contrast, the pulse-height spectra obtained under hole-drift conditions deteriorated because of the polarization phenomenon. (C) 2016 The Japan Society of Applied Physics

High-performance diamond radiation detectors produced by lift-off method
Takehiro Shimaoka, Junichi H. Kaneko, Masakatsu Tsubota, Hiroaki Shimmyo, Hideyuki Watanabe, Akiyoshi Chayahara, Hitoshi Umezawa, Shin-ichi Shikata
EPL, 113, 6, EPL ASSOCIATION, EUROPEAN PHYSICAL SOCIETY, Mar. 2016, [Peer-reviewed]
English, Scientific journal, For stable semiconductor detector operation under harsh environments, an ideal single-crystal diamond without a charge trapping centre is required. For this study, a self-standing single-crystal CVD diamond was fabricated using a lift-off method. The reduction of charge trapping factors such as structural defects, point defects, and nitrogen impurities, was attempted using 0.2% of low-methane concentration growth and using a full metal seal chamber. A high-quality self-standing diamond with strong free-exciton recombination emission was obtained. Charge collection efficiencies were 100.1% for holes and 99.8% for electrons, provided that epsilon(diamond) = 13.1 eV and epsilon(Si) = 3.62 eV. Energy resolutions were 0.38% for both holes and electrons. We produced a high-performance diamond radiation detector using the productive lift-off method. Copyright (C) EPLA, 2016

A diamond 14 MeV neutron energy spectrometer with high energy resolution
Takehiro Shimaoka, Junichi H. Kaneko, Kentaro Ochiai, Masakatsu Tsubota, Hiroaki Shimmyo, Akiyoshi Chayahara, Hitoshi Umezawa, Hideyuki Watanabe, Shin-ichi Shikata, Mitsutaka Isobe, Masaki Osakabe
REVIEW OF SCIENTIFIC INSTRUMENTS, 87, 2, AMER INST PHYSICS, Feb. 2016, [Peer-reviewed]
English, Scientific journal, A self-standing single-crystal chemical vapor deposited diamond was obtained using lift-off method. It was fabricated into a radiation detector and response function measurements for 14 MeV neutrons were taken at the fusion neutronics source. 1.5% of high energy resolution was obtained by using the C-12(n, alpha)Be-9 reaction at an angle of 100 degrees with the deuteron beam line. The intrinsic energy resolution, excluding energy spreading caused by neutron scattering, slowing in the target and circuit noises was 0.79%, which was also the best resolution of the diamond detector ever reported. (C) 2016 AIP Publishing LLC.

High-temperature characteristics of charge collection efficiency using single CVD diamond detectors
Masakatsu Tsubota, Junichi H. Kaneko, Daijirou Miyazaki, Takehiro Shimaoka, Katsunori Ueno, Takahiro Tadokoro, Akiyoshi Chayahara, Hideyuki Watanabe, Yukako Kato, Shin-ichi Shikata, Hitoshi Kuwabara
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 789, 50, 56, ELSEVIER SCIENCE BV, Jul. 2015, [Peer-reviewed]
English, Scientific journal, We synthesized single-crystal diamonds using microwave assisted plasma chemical vapor deposition and evaluated the temperature dependence of the diamond radiation detectors. We achieved charge collection efficiency of the hole of 96.9% with 3.0% energy resolution at 473 K. In the case of electrons. they became undetectable at temperatures higher than 373 K. It is possible that carrier trapping generated with frequency or the leakage current increased. The detector produced by the diamond in Diamond Detector Ltd. detector, operates normally at 523 K. Electrons can be measured at 573 K. We discussed the characteristics of charge carrier transport in the diamond detector to prepare for future use at higher temperatures. (C) 2015 Elsevier B.V. All rights reserved,

Preparation of translucent Gd2Si2O7:Ce polycrystalline thin plates and their scintillation performance for alpha-particles
Nishikata, M, Ueda, A, Higuchi, M, Kaneko, J.H, Tsubota, Y, Ishibashi, H
Opt. Mater., 45, 156, 160, ELSEVIER SCIENCE BV, Jul. 2015, [Peer-reviewed]
English, Scientific journal, Translucent Gd2Si2O7:Ce (GPS:Ce) polycrystalline plates were prepared via liquid-phase sintering using SiO2 as a self-flux, and their scintillation performances for alpha-particles were investigated. Dense sintered compacts comprising large grains, some of which were larger than 100 mu m in diameter, were successfully prepared by sintering at 1690 degrees C for 100 h. The best result was obtained with the powder comprising only <40 mu m particles. Any combination of powders of <40 mu m and <15 mu m resulted in inhomogeneous structures with smaller grains of about 50 mu m. A translucent GPS:Ce thin plate was fabricated by grinding the sintered compact that contained excess SiO2 of 8 mol%. Since the plate was composed of large grains, scattering at the grain boundaries was effectively suppressed and many of the grains virtually act as single crystals when the plate thickness was less than 100 mu m. Therefore, the decrease in the plate thickness brought increase in the total transmission, and light yield and energy resolution were consequently improved. When the plate thickness was 50 mu m, light yield was 82% as compared with that of a GPS:Ce single crystal as a reference, and energy resolution attained to 13%. (C) 2015 Elsevier B.V. All rights reserved.

Status of Beam Line Detectors for the BigRIPS Fragment Separator at RIKEN RI Beam Factory: Issues on High Rates and Resolution
Yuki Sato, Naoki Fukuda, Hiroyuki Takeda, Daisuke Kameda, Hiroshi Suzuki, Yohei Shimizu, DeukSoon Ahn, Daichi Murai, Naohito Inabe, Takehiro Shimaoka, Masakatsu Tsubota, Junichi H. Kaneko, Akiyoshi Chayahara, Hitoshi Umezawa, Shinichi Shikata, Hidekazu Kumagai, Hiroyuki Murakami, Hiromi Sato, Koichi Yoshida, Toshiyuki Kubo
Proceedings of the Conference on Advances in Radioactive Isotope Science (ARIS2014), Journal of the Physical Society of Japan, 29 Jun. 2015
International conference proceedings

High-temperature scintillation properties of orthorhombic Gd2Si2O7 aiming at well logging　　　　　　　　　　　　　　　
Tsubota, Y, Kaneko, J.H, Higuchi, M, Nishiyama, S, Ishibashi, H
Appl. Phys. Express, 8, 6, 062602, Jun. 2015, [Peer-reviewed]

Single-crystal CVD Diamond Detector for LowFnergy Charged Particles with Energies Ranging from 100 keV to 2 MeV
Yuki Sato, Hiroyuki Murakami, Takehiro Shimaoka, Masakatsu Tsubota, Junichi H. Kaneko
2015 4TH INTERNATIONAL CONFERENCE ON ADVANCEMENTS IN NUCLEAR INSTRUMENTATION MEASUREMENT METHODS AND THEIR APPLICATIONS (ANIMMA), IEEE, 2015
English, International conference proceedings, The performance of a diamond detector made of a single-crystal diamond grown by chemical vapor deposition was studied for charged particles, having energies ranging from 100 keV to 2 MeV. Energy peaks of these low-energy ions were clearly observed. However, we observed that the pulse height for individual incident ion decreases with increasing atomic number of the ions. We estimated the charge collection efficiency of the generated charge carriers by charged particle incident. The charge collection above similar to 95% is achieved for helium (He) with the energy above 1.5 MeV. On the other hand, the charge collection efficiency for heavy-ions shows lower values compared with that of He+, similar to 70% for silicon (Si+) and similar to 30% for gold (Au3+), at the same incident energy range, respectively.

Radiation hardness of a single crystal CVD diamond detector for MeV energy protons
Sato Yuki, Shimaoka Takehiro, Kaneko Junichi H, Murakami Hiroyuki, Isobe Mitsutaka, Osakabe Masaki, Tsubota Masakatsu, Ochiai Kentaro, Chayahara Akiyoshi, Umezawa Hitoshi, Shikata Shinichi
Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment, 784, 147, 150, 2015, [Peer-reviewed]

Response measurement of single-crystal chemical vapor deposition diamond radiation detector for intense X-rays aiming at neutron bang-time and neutron burn-history measurement on an inertial confinement fusion with fast ignition
Shimaoka T, Kaneko J.H, Arikawa Y, Isobe M, Sato Y, Tsubota M, Nagai T, Kojima S, Abe Y, Sakata S, Fujioka S, Nakai M, Shiraga H, Azechi H, Chayahara A, Umezawa H, Shikata S
Review of Scientific Instruments, 86, 5, AMER INST PHYSICS, 2015, [Peer-reviewed]
English, Scientific journal, A neutron bang time and burn history monitor in inertial confinement fusion with fast ignition are necessary for plasma diagnostics. In the FIREX project, however, no detector attained those capabilities because high-intensity X-rays accompanied fast electrons used for plasma heating. To solve this problem, single-crystal CVD diamond was grown and fabricated into a radiation detector. The detector, which had excellent charge transportation property, was tested to obtain a response function for intense X-rays. The applicability for neutron bang time and burn history monitor was verified experimentally. Charge collection efficiency of 99.5% +/- 0.8% and 97.1% +/- 1.4% for holes and electrons were obtained using 5.486 MeV alpha particles. The drift velocity at electric field which saturates charge collection efficiency was 1.1 +/- 0.4 x 10(7) cm/s and 1.0 +/- 0.3 x 10(7) cm/s for holes and electrons. Fast response of several ns pulse width for intense X-ray was obtained at the GEKKO XII experiment, which is sufficiently fast for ToF measurements to obtain a neutron signal separately from X-rays. Based on these results, we confirmed that the single-crystal CVD diamond detector obtained neutron signal with good S/N under ion temperature 0.5-1 keV and neutron yield of more than 109 neutrons/shot. (C) 2015 AIP Publishing LLC.

Performance comparison of scintillators for alpha particle detectors
Yuki Morishita, Seiichi Yamamoto, Kenji Izaki, Junichi H. Kaneko, Kohei Toui, Youichi Tsubota, Mikio Higuchi
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 764, 383, 386, ELSEVIER SCIENCE BV, Nov. 2014, [Peer-reviewed]
English, Scientific journal, Scintillation detectors for alpha particles are often used in nuclear fuel facilities. Alpha particle detectors have also become important in the research field of radionuclide therapy using alpha emitters. ZnS(Ag) is the most often used scintillator for alpha particle detectors because its light output is high. However, the energy resolution of ZnS(Ag)-based scintillation detectors is poor because they are not transparent. A new ceramic sample, namely the cerium doped Gd2Si2O7 (GPS) scintillator, has been tested as alpha particle detector and its performances have been compared to that one of three different scintillating materials: ZnS(Ag), GAGG and a standard plastic scintillator. The different scintillating materials have been coupled to two different photodetectors, namely a photomultiplier tube (PMT) and a Silicon Photo multiplier (Si-PM): the performances of each detection system have been compared. Promising results as far as the energy resolution performances (10% with PMT and 14% with Si-PM) have been obtained in the case of GPS and GAGG samples. Considering the quantum efficiencies of the photodetectors under Lest and their relation to the emission wavelength of the different scintillators, the best results were achieved coupling the GPS with the PMT and the GAGG with the Si-PM (C) 2014 Elsevier B.V. All rights reserved.

Single-crystal CVD diamond detector for high-resolution particle spectrometry
Y. Sato, H. Murakami, T. Shimaoka, M. Tsubota, J. H. Kaneko
EPL, 108, 4, EPL ASSOCIATION, EUROPEAN PHYSICAL SOCIETY, Nov. 2014, [Peer-reviewed], [Last author]
English, Scientific journal, The performance of a single-crystal diamond detector, grown by chemical vapour deposition, as an energy spectrometer for charged particles was studied. The detector was able to identify four different energies of (241) Am alpha-particles (5.389, 5.443, 5.486, and 5.545 MeV) thanks to a superior intrinsic energy resolution of similar to 0.4% (full width at half maximum). The electrode configuration, specifically the electric field configuration inside the diamond crystal, and the electrode materials, strongly affect the energy resolution for charged particles. The charge collection efficiency inside the diamond crystal was similar to 97% for both electrons and holes. Copyright (C) EPLA, 2014

Development of a Si-PM based alpha camera for plutonium detection in nuclear fuel facilities
Yuki Morishita, Seiichi Yamamoto, Kenji Izaki, Junichi H. Kaneko, Kohei Toi, Youichi Tsubota
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 747, 81, 86, ELSEVIER, May 2014, [Peer-reviewed]
English, Scientific journal, Alpha particles are monitored for detecting nuclear fuel material (i.e., plutonium and uranium) at nuclear fuel facilities. Currently, for monitoring the airborne contamination of nuclear fuel, only energy information measured by Si semiconductor detectors is used to distinguish nuclear fuel material from radon daughters. In some cases, however, such distinguishing is difficult when the radon concentration is high. In addition, a Si semiconductor detector is generally sensitive to noise. In this study, we developed a new alpha particle imaging system by combining a Si PM array, which is insensitive to noise, with a Ce-doped Gd3Al2Ga3O12(GAGG) scintillator, and evaluated our developed system's fundamental performance. The scintillator was 0.1-mm thick, and the light guide was 3.0 mm thick. An Am-241 source was used for all the measurements. We evaluated the spatial resolution by taking an image of a resolution chart. A 1.6 lp/mm slit was clearly resolved, and the spatial resolution was estimated to be less than 0.6-mm FWHM. The energy resolution was 13% FWHM. A slight distortion was observed in the image, and the uniformity near its center was within +/- 24%. We conclude that our developed alpha-particle imaging system is promising for plutonium detection at nuclear fuel facilities. (C) 2014 Elsevier B.V. All rights reserved.

Pulse shape distortion of output signals from single-crystal CVD diamond detector in few-GHz broadband amplifiers
Y. Sato, T. Shimaoka, J. H. Kaneko, H. Murakami, D. Miyazaki, M. Tsubota, A. Chayahara, H. Umezawa, S. Shikata
EPL, 106, 2, EPL ASSOCIATION, EUROPEAN PHYSICAL SOCIETY, Apr. 2014, [Peer-reviewed]
English, Scientific journal, The response of a diamond detector made from a single crystal grown by chemical vapour deposition was studied using a broadband amplifier. A short pulse width of similar to 1 ns for Am-241-alpha-particles was observed with a digital oscilloscope. To discuss pulse shape distortion from the detector in a measurement system, we simulated waveforms with a SPICE simulator using an equivalent circuit model that contained three main parts: detector, amplifier, and oscilloscope. In the simulation, we found that the pulse width spread by more than 200 ps following amplification. We discuss the effects of the detector read-out circuit time constant on the observed waveforms and confirm that the pulse width spread was restrained by use of a short time constant compared with carrier drift time in diamond crystals. Copyright (c) EPLA, 2014

Development of scintillator plates with high energy resolution for alpha particles made of GPS scintillator grains
Takehiro Shimaoka, Junichi H. Kaneko, Kenji Izaki, Youichi Tsubota, Mikio Higuchi, Shusuke Nishiyama
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 735, 110, 114, ELSEVIER SCIENCE BV, Jan. 2014, [Peer-reviewed]
English, Scientific journal, A scintillator plate with high energy resolution was developed to produce an alpha particle monitor used in nuclear fuel reprocessing plants and mixed plutonium-uranium oxide (MOX) fuel plants. Grains of a Gd2Si2O7 (GPS) scintillator of several 10 to 550 mu m were fixed on a glass substrate and were then mechanically polished. By increasing the size of scintillator grains and removing fine powders, the collected light yield and energy resolution for alpha particles were drastically improved. Energy resolution of 9.3% was achieved using average grain size of 91 mu m. Furthermore, the ratios between counts in a peak and total counts were improved by more than 60% by the further increase of grain size and adoption of mechanically polished surfaces on both sides. Beta and gamma ray influences were suppressed sufficiently by the thin 100 mu m scintillator plates. (C) 2013 Elsevier B.V. All rights reserved.

Crystal growth and scintillation properties of La0.2Ce0.05Gd1.75Si2O7 (La-GPS) single crystal with triclinic structure
Youichi Tsubota, Junichi H. Kaneko, Mikio Higuchi, Moyuru Minagawa, Hiroyuki Ishibashi
OPTICAL MATERIALS, 36, 3, 665, 669, ELSEVIER, Jan. 2014, [Peer-reviewed]
English, Scientific journal, La-substitute GPS with triclinic structure was grown using a top-seeded solution growth (TSSG) method to reduce concentration quenching by cerium. The low cerium concentration of 2.5% and triclinic crystal seed were chosen for crystal growth. The grown La-GPS single crystal showed light yield that was 1.2 times larger than NaI:Tl. Decay time and energy resolution for 662 keV gamma-rays were, respectively, 90 ns and 7.1%. (C) 2013 Elsevier B.V. All rights reserved.

Pulse height reduction effects of single-crystal CVD diamond detector for low-energy heavy ions
Sato Y, Shimaoka T, Kaneko J. H, Murakami H, Miyazaki D, Tsubota M, Chayahara A, Umezawa H, Shikata S
Epl, 104, 2, EPL ASSOCIATION, EUROPEAN PHYSICAL SOCIETY, 2013, [Peer-reviewed]
English, Scientific journal, The performance of a diamond detector made of single-crystal diamond grown by chemical vapour deposition was studied for heavy ions, having energy of 3MeV. Energy peaks of these low-energy ions were clearly observed. However, the pulse height for individual incident ion decreases with increasing atomic number of the ions. For understanding this pulse height reduction effect, we calculated the amount of ionizing and non-ionizing energy loss of incident ions in the diamond detector. The results of our calculation suggest the contribution of charge loss mechanisms other than the recombination effect of electron-hole pairs produced along the ionized track. We also mentioned the incomplete charge collection near the boundary region between the metal electrode and the diamond surface. Copyright (C) EPLA, 2013

Growth and evaluation of self-standing CVD diamond single crystals on off-axis (001) surface of HP/HT type IIa substrates
Junichi H. Kaneko, Fumiyuki Fujita, Yuta Konno, Takuto Gotoh, Norihiko Nishi, Hideyuki Watanabe, Akiyoshi Chayahara, Hitoshi Umezawa, Nobuteru Tsubouchi, Shinichi Shikata, Mitsutaka Isobe
DIAMOND AND RELATED MATERIALS, 26, 45, 49, ELSEVIER SCIENCE SA, Jul. 2012, [Peer-reviewed], [Lead author]
English, Scientific journal, As part of the development of diamond radiation detectors for energy spectrometry, quality improvement of CVD diamond single crystals was conducted mainly by measures of single diamond substrates. To suppress stress resulting from unconformity of lattice spacing between a substrate and a grown layer, which sometimes causes breakage, HP/HT type IIa diamond single-crystal substrates were adopted, and it resulted successfully. In addition an off-axis (001) surface was fabricated on the substrate to reduce abnormal growth. A lift-off method was adopted to reuse the HP/HT type IIa substrate with an off-axis (001) surface. Judging from peaks caused by free exciton recombination in cathode luminescence spectra, growth conditions more strongly affected the diamond crystal quality than substrates of any kind. Energy resolution of 0.6% for alpha particles was obtained by one CVD diamond single crystal. Charge collection efficiency of approximately 100% and 95% for holes and electrons was achieved. Step bunching caused by residual gas was observed on the grown CVD diamond surface. From the perspective of charge carriers' transportation measurement, the reduction of residual gas and optimization of growth conditions are indispensable. (c) 2012 Elsevier B.V. All rights reserved.

Response Measurement of Gd2Si2O7:Ce Scintillator for Alpha Particles
Youichi TSUBOTA, Junichi H. KANEKO, Kaori KONDO, Kenji IZAKI, Mikio HIGUCHI, Takehiro SHIMAOKA, Fumiyuki FUJITA, Shusuke NISHIYAMA
Progress in Nuclear Science and Technology, 3, 97, 99, The Atomic Energy Society of Japan, 2012
Scientific journal

Freestanding single crystal chemical vapor deposited diamond films produced using a lift-off method: Response to CL-particles from Am-241 and crystallinity
Tsubouchi N, Mokuno Y, Kakimoto A, Fujita F, Kaneko J. H, Yamada H, Chayahara A, Shikata S
Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms, 286, 313, 317, ELSEVIER, 2012, [Peer-reviewed]
English, Scientific journal, Thick (similar to 100 mu m) undoped diamond films were grown homoepitaxially on single crystal (SC) diamond substrates by microwave plasma chemical vapor deposition (CVD). To form a freestanding SC diamond film (plate), the substrate was pre-ion-implanted with high-energy ion beams before the film growth, and after the thick-film deposition, the substrate was eliminated using a lift-off method, resulting in fabrication of a SC CVD diamond plate. Two samples were prepared; sample 1 was grown on a (001) oriented, nitrogen doped CVD SC diamond at similar to 900 degrees C with the input microwave power of 1.7 kW, while sample 2 was grown on a (001) oriented, high-pressure high-temperature synthesized type-1b SC diamond at similar to 900 degrees C with the input microwave power of 1.25 kW. The formed SC plates have high optical transparencies, indicating no remarkable optical absorptions seen in the wavelength from ultraviolet to near infrared. The photoluminescence (PL) spectra of both samples show strong free exciton FE peaks, while in sample 2 relatively strong optical emissions corresponding to nitrogen related centers were observed in the visible region. After the metal electrodes were formed on both faces of the SC diamond plate to fabricate a sandwich-type diamond particle detector, the energy spectra of 5.486 MeV alpha-particles from Am-241 were measured. The charge collection efficiencies (CCEs) of sample 1 were CCE = 98% for a hole transport and CCE = 89% for an electron transport, respectively, while CCEs of sample 2 were CCE = 80% for a hole transport and CCE = 78% for an electron transport, respectively. These results indicate that both holes and electrons in sample 2 were trapped much more than those in sample 1. Possible candidates of carrier capture centers are nitrogen and/or nitrogen-vacancy centers observed in PL, nonradiative defect (complex) centers, extended defects such as threading dislocations observed in micrographs taken with polarizers. The different growth conditions most likely affected crystallinity and responses to alpha-particles of the samples. (C) 2011 Elsevier B.V. All rights reserved.

Characterization of a sandwich-type large CVD single crystal diamond particle detector fabricated using a lift-off method
Tsubouchi N, Mokuno Y, Kakimoto A, Konno Y, Yamada H, Chayahara A, Kaneko J. H, Fujita F, Shikata S
Diamond and Related Materials, 24, 74, 77, ELSEVIER SCIENCE SA, 2012, [Peer-reviewed]
English, Scientific journal, Crystallinity of a freestanding large (size: similar to 9 x 7 mm) undoped single crystal (SC) diamond film grown by plasma chemical vapor deposition (CVD) and radiation response of a sandwich-type radiation detector made from this SC plate to a particles were investigated. The freestanding SC film was formed by elimination of a substrate using a so-called "lift-off method" after the growth of a thick-film on a pre-ion-implanted substrate. The formed SC plate has a high optical transparency, indicating no remarkable optical absorption seen in the wavelength from ultraviolet to near-infrared region. In the energy spectra of 5.486 MeV alpha-particles, relatively sharp peaks were observed for both hole and electron transits. For the hole transit, the peak resolution of the pulse height distribution and charge collection efficiency (CCE) were similar to 0.7% and 98%, respectively. On the other hand, for the electron transit, the peak resolution and CCE obtained were similar to 4.4% and 89%, respectively. In the photoluminescence spectrum at room temperature, a strong sharp peak around 235 nm corresponding to free exciton and a weak visible band mainly related to nitrogen-vacancy complex were observed. The spectral width of the (004) plane X-ray rocking curve was 16.5 ''. The micrograph taken using crossed-polarizers demonstrated that there are some white regions and four-petaled patterns, originating from internal strain and most likely threading dislocations, respectively. (C) 2011 Elsevier B.V. All rights reserved.

Real-time 4-D radiotherapy for lung cancer
Hiroki Shirato, Rikiya Onimaru, Masayori Ishikawa, Jun-ichi Kaneko, Tsuguhide Takeshima, Kenta Mochizuki, Shinichi Shimizu, Kikuo Umegaki
CANCER SCIENCE, 103, 1, 1, 6, WILEY-BLACKWELL, Jan. 2012, [Peer-reviewed]
English, Respiratory motion considerably influences dose distribution, and thus clinical outcomes in radiotherapy for lung cancer. Breath holding, breath coaching, respiratory gating with external surrogates, and mathematical predicting models all have inevitable uncertainty due to the unpredictable variations of internal tumor motion. The amplitude of the same tumor can vary with standard deviations >5 mm occurring in 23% of T12N0M0 non-small cell lung cancers. Residual motion varied 16 mm (95th percentile) for the 40% duty cycle of respiratory gating with external surrogates. The 4-D computed tomography is vulnerable to problems relating to the external surrogates. Real-time 4-D radiotherapy (4DRT), where the temporal changes in anatomy during the delivery of radiotherapy are explicitly considered in real time, is emerging as a new method to reduce these known sources of uncertainty. Fluoroscopic, real-time tumor-tracking technology using internal fiducial markers near the tumor has +/- 2 mm accuracy, and has achieved promising clinical results when used with X-ray therapy. Instantaneous irradiation based on real-time verification of internal fiducial markers is considered the minimal requisite for real-time 4DRT of lung cancers at present. Real-time tracking radiotherapy using gamma rays from positron emitters in tumors is in the preclinical research stage, but has been successful in experiments in small animals. Real-time tumor tracking via spot-scanning proton beam therapy has the capability to cure large lung cancers in motion, and is expected to be the next-generation real-time 4DRT. (Cancer Sci 2012; 103: 16)

Improvement of crystal quality of a homoepitaxially grown diamond layer by a plasma etching treatment for a diamond substrate　　　　　　　　　　　　　　　
PROGRESS IN NUCLEAR SCIENCE AND TECHNOLOGY, 1, 255, 258, 2011

Luminescence properties and Crystal structures of Pr-doped gadolinium pyrosilicate　　　　　　　　　　　　　　　
PROGRESS IN NUCLEAR SCIENCE AND TECHNOLOGY, 288, 291, 2011

Improvmement of scintillation characteristics of FZ growth Ce:GPS crystals by annealing in air　　　　　　　　　　　　　　　
PROGRESS IN NUCLEAR SCIENCE AND TECHNOLOGY, 1, 279, 281, 2011

Fusion product diagnostics planned for Large Helical Device deuterium experiment
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, H. Yamada
REVIEW OF SCIENTIFIC INSTRUMENTS, 81, 10, 10D310-1-10D310-5, AMER INST PHYSICS, Oct. 2010, [Peer-reviewed]
English, 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 gamma-ray diagnostics. (C) 2010 American Institute of Physics. [doi:10.1063/1.3492383]

Measurement of charge carrier's transportation in a large size self-standing CVD single crystal diamond film fabricated using lift-off method
F. Fujita, A. Kakimoto, J. H. Kaneko, N. Tsubouchi, Y. Mokuno, A. Chayahara, K. Sato, Y. Konno, A. Homma, S. Shikata, M. Furusaka
DIAMOND AND RELATED MATERIALS, 19, 2-3, 162, 165, ELSEVIER SCIENCE SA, Feb. 2010, [Peer-reviewed]
English, Scientific journal, Using lift-off method, we synthesized large self-standing plasma CVD diamond films on various substrates. Charge carrier transportation in diamond was measured using alpha particle measurements and TOF methods with a short-pulsed UV laser. The high-quality films were synthesized rapidly. We observed the maximum transit time of holes and electrons shorter than 5 ns. The lift-off method is useful to fabricate the high-quality diamond with excellent drift velocities of the charge carrier. The charge transport characteristics of our diamond films are comparable to those of a commercially available (Element Six Ltd.) electronics grade Ila diamond single crystal. (C) 2009 Elsevier B.V. All rights reserved.

Phase Relations around the Pyrosilicate Phase in the Gd2O3-Ce2O3-SiO2 System
Sohan Kawamura, Mikio Higuchi, Junichi H. Kaneko, Shusuke Nishiyama, Jun Haruna, Shohei Saeki, Shunsuke Ueda, Kazuhisa Kurashige, Hiroyuki Ishibashi, Michihiro Furusaka
CRYSTAL GROWTH & DESIGN, 9, 3, 1470, 1473, AMER CHEMICAL SOC, Mar. 2009, [Peer-reviewed]
English, Scientific journal, The melting and solidification behavior of the (Gd0.9Ce0.1)(2)Si2O7 (Ce:GPS) which shows attractive scintillation performance was investigated by means of the slow cooling floating zone (SCFZ) method. Although Ce:GPS melts incongruently, the peritectic composition is estimated to be very close to the GPS composition, less than 67.0 mol % of SiO2 in the (Gd,Ce)(2)O-3-SiO2 system. Constitutional supercooling occurred when approximately 70% volume of the melt was solidified, consequently, the lamellar structure consists of Ce:GPS and the amorphous phase was obtained. On the basis of our study, it is estimated that a volume of 70% of the starting material, whose composition is SiO2 = 67 mol % in the (Gd,Ce)(2)O-3-SiO2 system at Ce 10 mol %, can be solidified as the GPS phase using top-seeded solution growth (TSSG) with the self-flux of SiO2.

Electron emission characteristics of needle type semiconductor diamond electron emitters by pulsed bias operation and X-ray generation
S. Fukumoto, A. Homma, J. H. Kaneko, Y. Nishibayashi, Y. Yamamoto, A. Ueda, F. Fujita, S. Kawamura, K. Sato, T. Imai, M. Furusaka
DIAMOND AND RELATED MATERIALS, 18, 2-3, 287, 291, ELSEVIER SCIENCE SA, Feb. 2009, [Peer-reviewed]
English, Scientific journal, Electron emission characteristics of needle-type semiconductor diamond electron emitters with pulsed bias operation were evaluated. An X-ray generation experiment was performed. Fowler-Nordheim plotting confirmed that field emission completely governed the electron emission. Maximum emission current of 4.2 mA was achieved using an n-type diamond needle. The needle tip, with area smaller than 1 mu m(2), had estimated electron emission density greater than 4.2 x 10(5) A/cm(2). The effective emission area obtained from the Fowler-Nordheim plot was several 10(-13) cm(2). For adopting and emission area of 1 X 10(-12) cm(2), the estimated electron emission density was higher than 4.2 x 10(9) A/cm(2). Furthermore, the average emission current was 0.5-0.6 mA. This large electron emission was continued for several seconds and repeatable. A threshold electric field existed for electron emission higher than 50 kV/mm; pulsed electron emissions of less than 30 ms were created by slow triangular waveform shaped bias voltage supplied at frequencies of 5-10 Hz. An improved vacuum level and pulsed bias operation prevented damage to diamond electron emitters and steady electron emission better than with thermoelectronic emission and high bias voltage supply in DC mode; continuous X-ray generation of 1 h was achieved. (C) 2008 Elsevier B.V. All rights reserved.

Scintillation characteristics of Ce:Gd2Si2O7 (Ce 2.5-30 mol%) single crystals prepared by the floating zone method
Kawamura S, Kaneko, J.H, Higuchi, M, Haruna, J, Saeki S, Fujita, F, Homma, A, Nishiyama, S, Ueda, S, Kurashige K, Ishibashi, H, Furusaka, M
IEEE Trans. Nucl. Sci., 56, 1,Pt.2, 328, 330, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2009, [Peer-reviewed]
English, Scientific journal, Cerium-doped gadolinium pyrosilicate single crystals Ce : Gd2Si2O7 (Ce:GPS) with various Cc concentrations of 2.5-30 mol% with respect to the total rare-earth sites were prepared by the floating zone method. Their scintillation performances were investigated under irradiation of gamma rays of Cs-137. The Ce concentration dependence of scintillation characteristics and high-performance scintillation characteristics were obtained: 3-6 times greater light output than that of BGO single crystals, rapid decay, and good energy resolutions of 5.1-8.4%. Furthermore, X-ray diffraction patterns of Ce:GPS revealed Ce concentration dependence of the crystal structure of Ce:GPS.

Development of Layered Type Single Crystalline Diamond Radiation Detector as an Energy Spectrometer
Junichi H. Kaneko, Tokuyuki Teraji, Takahiro Imai, Yuuki Hirai, Satoshi Yoshizaki, Kei Satou, Souhan Kawamura, Yusuke Oshiki, Fumiyuki Fujita, Akira Homma, Toshimichi Ito, Michihiro Furusaka
JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, Supplement 5, 391, 394, TAYLOR & FRANCIS LTD, Jun. 2008, [Peer-reviewed], [Lead author]
English, Scientific journal, Radiation detectors were fabricated with layered structure diamonds comprising several micrometers of a boron-doped single crystal diamond and 20 mu m of insulating single crystal diamond layers grown on a HP/HT-type Ib diamond single crystal Substrate. To improve the yield rate of CVD diamond radiation detectors this approach was adopted. The detectors had rectification characteristics because of their boron-doped diamond contact and aluminum Schottky contact. The leakage current of one detector was less than 0.2 pA at reversed bias voltage of +50 V Energy resolutions of 2.6% and 2.8% for alpha particles from Am-241 were achieved using these detectors. The rise time of a leading edge of an Output signal from one detector was less than 20 ns, which was the fastest rise time of the measurement system; drift velocities of charge carriers were estimated to be faster than 1 x 10(5) cm/s. In addition, cathode luminescence spectra of insulating diamond layers were measured; peaks caused by free exciton recombination and 'band A' were observed. Improved crystallinity of the boron-doped diamond layer helps realization of a layered-type diamond radiation detector with higher energy resolution.

Measurement of charge carrier dynamics in diamond thin films using a fast TOF system with a UV pulsed laser
Y. Oshiki, J. H. Kaneko, F. Fujita, A. Homma, H. Watanabe, K. Meguro, Y. Yamamoto, T. Imai, K. Sato, K. Tsuji, S. Kawamura, M. Furusaka
DIAMOND AND RELATED MATERIALS, 17, 4-5, 833, 837, ELSEVIER SCIENCE SA, Apr. 2008, [Peer-reviewed]
English, Scientific journal, Charge carrier dynamics in CVD homoepitaxial diamond thin films were evaluated. Thicknesses of these thin diamond films were 4.5-14 mu m. Measurement was carried out using a fast TOF system with time resolution of 150 ps. This system adopted the localized irradiation mechanism of a 213-nm UV pulsed laser. Induced current caused by charge carrier motion was simulated by a one-dimensional approximation. Then measured signals were analyzed using the physical model of induced current that was confirmed through the simulation. The best lifetimes, T, of electrons and holes in evaluated diamond films were 1.8 +/- 0.3 ns for both charge carriers. However, drift velocities and mean free paths of trapping were not determined because insufficient charge carriers arrived at the further side electrode without trapping. (C) 2008 Elsevier B.V. All fights reserved.

Development of an evaluation system for electron emission characteristics and generation of X-rays using a needle type semiconductor diamond electron emitter
S. Fukumoto, A. Honma, J. H. Kaneko, Y. Nishibayashi, A. Ueda, Y. Yamamoto, T. Imai, F. Fujita, S. Kawamura, M. Furusaka
DIAMOND AND RELATED MATERIALS, 17, 4-5, 764, 767, ELSEVIER SCIENCE SA, Apr. 2008, [Peer-reviewed]
English, Scientific journal, Emission currents and other characteristics of needle type diamond electron emitters were evaluated for application to diamond X-ray sources. The evaluation system consisted of a Pyrex glass vacuum chamber, a turbo molecular pump, and a - 50 kV high-voltage supplier. A needle type phosphorus-doped semiconductor diamond electron emitter was kept at 600 degrees C by ohmic heating in a vacuum environment; emission current of ca. 1.1 mu A was observed with bias voltage of - 50 W In addition, the electron orbit and intensity were estimated using an electron optics and electron gun design program 'EGUN'. Great differences were apparent between experimental and calculated results: 64 mu A electron emission current. This result was probably the result of a change in the shape of the tip of the diamond electron emitter. X-rays were generated using electrons from the diamond electron emitter with a tungsten target; energy spectra of the generated X-rays were measured. Then fluoroscopy was carried out. (C) 2008 Elsevier B.V. All rights reserved.

Neutron irradiation test of an ATLAS Thin Gap Chamber
H. Ohshita, H. Iwasaki, J. Kaneko, H. Kiyamura, M. Nakao, A. Ochi, K. Ochiai, T. Takeshita, S. Tanaka
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 587, 2-3, 259, 265, ELSEVIER SCIENCE BV, Mar. 2008, [Peer-reviewed]
English, Scientific journal, Thin Gap Chambers (TGCs) will be used as a muon trigger device in the end-cap regions of the ATLAS detector. The detector will be placed in an experimental cavern approximately 100 m below the ground surface. A large amount of neutron background is expected in the cavern. Recoiled nuclei, mostly protons, emerging from the neutron interaction provide a much larger energy deposit in the gas volume than that of the minimum ionizing particle (MIP). This might cause aging and improper operation of the TGC. In order to investigate such influences, we performed a test on the operation stability of a real-use TGC under a much higher neutron flux environment than that expected in the ATLAS cavern. This paper describes the experimental results of the irradiation test using 14-MeV neutrons. The maximum flux was 3.2 x 10(5) HZ/cm(2), Which was effectively approximately nine times higher than that at the worst TGC location. It was proved that the TGC was immune to such a flux and instantaneous large signals originating from the neutrons. The mean output charge from the recoil proton at the nominal operation voltage was found to be approximately 30 times larger than that of MIP. The total fluence was 1.4 x 10(10) neutrons/cm(2), up to which the TGC operated stably and no detector deterioration was observed. This corresponds to approximately nine months of ATLAS operation at the nominal luminosity of 10(34) cm(2)/S. (C) 2008 Elsevier B.V. All rights reserved.

Investigation of Ce-doped Gd(2)Si(2)O(7) as a scintillator material
Sohan Kawamura, Junichi H. Kaneko, Mikio Higuchi, Fumiyuki Fujita, Akira Homma, Jun Haruna, Shohei Saeki, Kazuhisa Kurashige, Hiroyuki Ishibashi, Michihiro Furusaka
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 583, 2-3, 356, 359, ELSEVIER SCIENCE BV, Dec. 2007, [Peer-reviewed]
English, Scientific journal, As a novel scintillation material, the use of Ce-doped Gd(2)Si(2)O(7) was investigated. In fact, (Gd(0.9)Ce(0.1))(2)Si(6)O(7) powder showed about 1.2 times greater light output than Gd(2)SiO(5) (GSO) single crystals for alpha particles of (241)Am. Furthermore, a fast decay constant of 52 ns was obtained for alpha-particles of (241)Am. Relations between the Ce concentration, crystal structure, and luminescence characteristics were also elucidated. Results of these studies show that heavy Ce doping alters the Gd(2)Si(2)O(7) crystal structure and that the luminescence intensity is dependent not on Cc concentration, but on the triclinic structure formed by heavy Cc doping. (c) 2007 Elsevier B.V. All rights reserved.

Floating zone growth and scintillation characteristics of cerium-doped gadolinium pyrosilicate single crystals
S. Kawamura, J. H. Kaneko, M. Higuchi, T. Yamaguchi, J. Haruna, Y. Yagi, K. Susa, F. Fujita, A. Homma, S. Nishiyama, K. Kurashige, H. Ishibashi, M. Furusaka
IEEE TRANSACTIONS ON NUCLEAR SCIENCE, 54, 4, 1383, 1386, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Aug. 2007, [Peer-reviewed]
English, Scientific journal, Growth of cerium-doped gadolinium pyrosilicate (Ce:Gd2Si2O7) single crystals, which show 2.5 times greater light output for gamma-rays and five times greater light output for alpha-particles than GSO single crystals, is accomplished using the floating zone growth method (FZ method). Although growth of Gd2Si2O7 (GPS) single crystal is considered to be difficult because it melts incongruently according to the phase diagram of Gd2O3-SiO2 system, we attempted crystal growth of Ce:GPS because of the possibility that heavy Ce doping would change the phase diagram. Transparent single crystals were obtained, although some cracks were observed in the crystals. The crystal structure was triclinic with P/1 space group and density of 5.5 g/cm(3). Two peaks, which were observed using photoluminescence spectrometry at 372 nm and 394 nm, were attributed to 5d-4f transition in Ce3+ ion. Decay times of Ce:GPS scintillation were 46 ns for gamma-ray excitation and 39 ns for alpha-particle excitation. We consider that fabrication of crack free crystals will improve the energy resolution.

Development of a radiation detector made of a cubic boron nitride polycrystal
J. H. Kaneko, T. Taniguchi, S. Kawamura, K. Satou, F. Fujita, A. Homma, M. Furusaka
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 576, 2-3, 417, 421, ELSEVIER SCIENCE BV, Jun. 2007, [Peer-reviewed], [Lead author]
English, Scientific journal, Radiation detectors were fabricated using single and polycrystalline cubic boron nitride (cBN) crystals synthesized using a high-pressure and high-temperature (HP/HT) method. Although cBN single crystals obtained using a barium BN solvent system were nearly colorless and displayed high electrical resistance, in contrast to conventional amber-colored crystals, the single crystals exhibit a leakage current that renders them unsuitable for use in a detector. In contrast, a detector made of a cBN polycrystal synthesized by direct transformation had a very low leakage current of 0.2pA with bias voltage of 100V; it functioned as a radiation detector. From an experiment using alpha-particles, holes traversed a longer distance than electrons. It had a fast rise time of approximately 300ns. The detector also showed sensitivity to neutrons. However, output signals were smaller than the expected voltage from the experiment using alpha-particles, probably because of charge accumulation from the high-neutron flux. (C) 2007 Elsevier B.V. All rights reserved.

Development of a TOF measurement system of charge carrier dynamics in diamond thin films using a UV pulsed laser
F. Fujita, Y. Oshiki, J. H. Kaneko, A. Homma, K. Tsuji, K. Meguro, Y. Yamamoto, T. Imai, H. Watanabe, T. Teraji, S. Kawamura, M. Furusaka
DIAMOND AND RELATED MATERIALS, 15, 11-12, 1921, 1925, ELSEVIER SCIENCE SA, Nov. 2006, [Peer-reviewed]
English, Scientific journal, A fast TOF measurement system with 150 ps time resolution for transport behavior of free charge carriers in an intrinsic diamond film by using a UV pulsed laser was developed. The 213 nm UV laser light narrowed to approximately 80 mu m widths could locally create hole-electron pairs in selected locations on a diamond film between two parallel electrodes on the surface. This system measured accurate charge transport characteristics in a diamond film, because created charge carriers moved in a part of the diamond film where they did not get any influence from the laser irradiation. Diamond samples used for verification of the TOF system were intrinsic CVD diamond films with thickness between 4 and 10 mu m grown on HP/HT diamond substrates. Transit time of holes for one diamond film was 4.7 ns with a traverse distance of 250 mu m. The local irradiation of laser made it possible to measure transport characteristics of electrons and holes separately. In addition, it substantially reduced the influence of photoelectron, because the laser beam did not irradiate electrodes. Through several examinations, excellent reliability of the TOF system was confirmed. (c) 2006 Elsevier B.V. All rights reserved.

Possibility of using a PMN-PT single crystal as a neutron optical device
S. Kawamura, J. H. Kaneko, H. Fujimoto, Y. Otake, F. Fujita, A. Homma, T. Sawamura, P. Mikula, M. Furusaka
PHYSICA B-CONDENSED MATTER, 385-86, 1277, 1279, ELSEVIER SCIENCE BV, Nov. 2006, [Peer-reviewed]
English, Scientific journal, Variations of the Bragg diffraction angle induced by electric fields on piezoelectric single crystal were investigated with the aim of exploiting such crystals for novel neutron devices. A (1-x)(Pb(Mg1/3Nb2/3)O-3)-x(PbTiO3) (PMN-PT) single crystal With strong piezoelectric characteristics was used in the experiment. The sample was poled along < 001 > direction before the experiment. In the course of diffraction measurements, a 0.3 degrees change was observed in the diffraction angle at the maximum induced by the electric field. The diffraction angle variation shows time-dependent behavior, which can be well described using a single exponential decay limited to a saturated value. This effect is considered a result of a change of the domain structure brought about through long-term application of an electric field for several hours. The obtained preliminary results confirmed the possibility of using a ferroelectric crystal as a neutron optical device. (c) 2006 Elsevier B.V. All rights reserved.

Saturation drift velocity measurement for CVD diamond by combination of a charge distribution measurement and a TOF method using a UV pulsed laser
Y. Oshiki, J. H. Kaneko, F. Fujita, K. Hayashi, K. Meguro, A. Homma, S. Kawamura, Y. Yokota, Y. Yamamoto, K. Kobashi, T. Imai, T. Sawamura, M. Furusaka
DIAMOND AND RELATED MATERIALS, 15, 10, 1508, 1512, ELSEVIER SCIENCE SA, Oct. 2006, [Peer-reviewed]
English, Scientific journal, Drift velocities of charge carriers in polycrystalline diamonds were measured by a self-triggered time-of-flight (TOF) method with alpha particles based on a radiation measurement technique. Based on these measured results, a synthesis method for polycrystalline diamond was verified, and the electric properties of polycrystalline diamonds were improved; drift velocity was increased from 5 x 10(2) to 3 x 10(4) cm/s. The mean free paths (MFPs) of capture of charge carriers in a CVD single crystal diamond was obtained by induced charge distribution measurements with alpha particles, and drift velocity was measured by another TOF method using. a UV pulsed laser. MFPs of capture of electron and hole in a CVD single crystal diamond were determined to be 5.4 and 9.6 mu m, respectively; the hole and electron drift velocities were 5 x 10(5) cm/s and 3 x 10(5) cm/s in an electric field of 24.4 kV/cm, respectively. For diamond, short transit times of several nanoseconds and short MFPs of capture in several micrometers were successfully obtained for the first time by combining of these methods. (c) 2005 Elsevier B.V. All rights reserved.

Thin gap chamber performance tests under several MeV neutron sources
Atsuhiko Ochi, Hironori Kiyamura, Junichi Kaneko, Hidetoshi Ohshita, Tohru Takeshita, Shuji Tanaka, Hiroyuki Iwasaki, Kentaro Ochiai, Makoto Nakao
REVIEW OF SCIENTIFIC INSTRUMENTS, 77, 10, 10E709, AMER INST PHYSICS, Oct. 2006, [Peer-reviewed]
English, Scientific journal, Thin gap chamber (TGC) is a very thin multiwire proportional chamber of only a few millimeters. It has a quick response (about 20 ns), and its production costs are relatively low. TGCs have been used as large area detectors in high energy physics such as Large Electron-Positron collider (LEP) and will be used in the Large Hadron collider (LHC) experiment. However, the characteristics of TGCs under neutrons are not yet clearly understood. As the energy deposits of several MeV neutrons in TGCs are large, the possible effect of these deposits on the operation of the detector is a concern. We studied TGC performance in relation to efficiency, charge distribution, and operation stability using several gas mixtures (CO2/n-pentane and CF4/n-pentane) with 2.5 and 14 MeV neutron sources at Fusion Neutronics Source (FNS) in Japan Atomic Energy Agency. Operation stability using a CF4 based gas was more than 100 times greater than with CO2 based gas, while the minimum ionizing particle signal gain was almost the same. The detection efficiencies were around 0.1% (14 MeV) and 0.02% (2.5 MeV). These results are consistent with our simulation studies. (c) 2006 American Institute of Physics.

Analysis of neutron propagation from the skyshine port of a fusion neutron source facility
M Wakisaka, J Kaneko, F Fujita, K Ochiai, T Nishitani, S Yoshida, T Sawamura
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 554, 1-3, 347, 355, ELSEVIER SCIENCE BV, Dec. 2005, [Peer-reviewed]
English, Scientific journal, The process of neutron leaking from a 14 MeV neutron source facility was analyzed by calculations and experiments. The experiments were performed at the Fusion Neutron Source (FNS) facility of the Japan Atornic Energy Institute, Tokai-mura, Japan, which has a port on the roof for skyshine experiments, and a 3 He counter surrounded with a polyethylene moderator of different thicknesses was used to estimate the energy spectra and dose distributions. The He-3 counter with a 3-cm-thick moderator was also used for dose measurements, and the doses evaluated by the counter Counts and the calculated count-to-dose conversion factor agreed with the calculations to within similar to 30%. The dose distribution was found to fit a simple analytical expression,
D(r) = Q(D) exp(-r/lambda(D))/r
and the parameters Q(D) and lambda(D) are discussed. (c) 2005 Published by Elsevier B.V.

Development of high resolution position sensitive UV detector based on highly oriented polycrystalline diamond
K Tsuji, K Hayashi, JH Kaneko, F Fujita, A Homma, Y Oshiki, T Sawamura, M Furusaka
DIAMOND AND RELATED MATERIALS, 14, 11-12, 2035, 2038, ELSEVIER SCIENCE SA, Nov. 2005, [Peer-reviewed]
English, Scientific journal, UV position-sensitive sensor using a polycrystalline highly-oriented diamond film with a sensitive area of 2 x 4.5 mm(2) developed, and a proof-of-concept Study was conducted. The charge division method was employed to establish the position when the light hits the sensitive area. A fifth higher harmonic of a Nd:YAG laser with pulse width of 100 ps was used as a light source. The position resolution was 0.25 mm, and there was good position linearity throughout the sensitive area. Considering the possibility of light-spot broadening due to diffraction by the slit, the sensor may have a better resolution than that indicated by the result. But the electric-field strength of some parts of the crystal was insufficient, the response time was relatively slow, approximately 0.5 ins. (c) 2005 Elsevier B.V. All rights reserved.

Radiation detector made of a high-quality polycrystalline diamond
JH Kaneko, T Tanaka, S Kawamura, Y Oshiki, K Tsuji, M Katagiri, K Ochiai, T Nishitani, F Fujita, T Sawamura, T Iida, M Furusaka
DIAMOND AND RELATED MATERIALS, 14, 11-12, 2027, 2030, ELSEVIER SCIENCE SA, Nov. 2005, [Peer-reviewed], [Lead author]
English, Scientific journal, Radiation detector was made of a high-quality CVD polycrystalline diamond composed of frost column like structure diamond grains, and induced charge distribution spectra and drill velocities were measured by using alpha particles. As a result, the CVD polycrystalline achieved maximum induced charge of 83% of HP/HT type IIa diamond. Moreover, the CVD crystal had lower charge loss on electrons compared with the HP/HT type IIa diamond. Drift velocities of electrons and holes were nu(e)=7.7 x 10(4) and nu(h)=7.3 x 10(4) cm/s at an electric field of 20 kV/cm, respectively. In addition, response function measurement for 14 MeV neutrons was carried Out. (c) 2005 Elsevier B.V. All rights reserved.

Radiation tolerance of type IIa synthetic diamond detector for 14 MeV neutrons
T Tanaka, JH Kaneko, Y Kasugai, M Katagiri, H Takeuchi, T Nishitani, T Iida
DIAMOND AND RELATED MATERIALS, 14, 11-12, 2031, 2034, ELSEVIER SCIENCE SA, Nov. 2005, [Peer-reviewed]
English, Scientific journal, Radiation tolerance of a type IIa synthetic diamond detector was examined from irradiation of mono-energetic 14 MeV neutrons. Measurements of I-V (current-voltage) characteristics and energy spectrum for 5.486 MeV alpha particles were performed after neutron irradiation. In the I-V characteristics measurement, enhancement of rectification was observed after neutron irradiation of up to 2.0 x 10(12) n/cm(2). Concurrently with the enhancement of rectification, significant decrease in signal amplitude was observed in energy spectrum measurement for alpha particles. It is considered that these changes were due to increase in the concentration of defects acting as shallow energy levels in the forbidden band. For neutron irradiation of higher than 1.6 x 10(13) n/cm(2), weakening of the rectification characteristics and recovery of the signal amplitude were observed. These changes imply that deep energy levels, which were also considered to be introduced by defects, were dominant and weakened the effects of the shallow energy levels. Increase in the concentration of the deep trapping levels resulted in gradual decrease of the signal amplitude and degradation in the energy resolution. The peak for the alpha particles was obtained up to 5.5 x 10(13) n/cm(2). (c) 2005 Elsevier B.V. All rights reserved.

Development of a charge-carrier drift velocity measurement system in diamonds by using a UV pulse laser
F Fujita, A Homma, Y Oshiki, JH Kaneko, K Tsuji, K Meguro, Y Yamamoto, T Imai, T Teraji, T Sawamura, M Furusaka
DIAMOND AND RELATED MATERIALS, 14, 11-12, 1992, 1994, ELSEVIER SCIENCE SA, Nov. 2005, [Peer-reviewed]
English, Scientific journal, There are continuing efforts of developing faster FETs and diamond is one of the strong candidates as a base semiconductor. Since the upper-limit-frequency of diamond FETs determines saturated drift velocities of charge-carriers, we need to first characterize diamond to develop better FETs. It is, however, not easy to measure the velocities with response time of less than 20 ns. Therefore, we developed a drift velocity measurement system using a time-of-flight (TOF) technique with a UV laser with 100 ps pulse width. In order to realize response times faster than 20 ns, we employed a 50 Omega coaxial cable as a load, with which we could effectively reduce the stray capacitance and inductance, and also, suppress reflections in the signal which gives false signals. As a result, we can measure carrier-transit times shorter than 10 ns. (c) 2005 Elsevier B.V. All rights reserved.

Development of a wide-range paired scintillator with optical fiber neutron monitor for BNCT irradiation field study
M Ishikawa, H Kumada, K Yamamoto, J Kaneko, G Bengua, H Unesaki, Y Sakurai, K Tanaka, T Kosako
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 551, 2-3, 448, 457, ELSEVIER SCIENCE BV, Oct. 2005, [Peer-reviewed]
English, Scientific journal, A wide range thermal neutron detector was developed based on the Scintillator with Optical Fiber (SOF) detector which has been previously used for thermal neutron monitoring during boron neutron capture therapy irradiation. With this new detector system we intended to address the issues of real-time thermal neutron flux measurement and the simultaneous measurement of a wide range of thermal neutron flux in a BNCT irradiation field which were difficult to implement with the gold wire activation method.
The dynamic range of linearity of the SOF detector was expanded by using a plastic scintillator with a rapid decay time. On the other hand, the contribution of gamma rays and fast neutrons in the measured signals were compensated from those obtained by a pair of SOF detectors, one with a (LiF)-Li-6 neutron converter and the other without. The discrimination level for the measured signals was also optimized to further reduce the contribution of gamma rays and fast neutrons signals. A non-paralyzable system model was applied to correct for the dead-time in the detector system.
A good agreement between the thermal neutron flux measured by the gold wire activation method and the paired SOF detector system was observed. However, measurements which would normally take a few days to perform with the gold wire activation method were obtained in just about 15 min using the SOF detector system. We also confirmed the dynamic range of linearity for the SOF detector system to be in the order of magnitude of 10(4). (c) 2005 Elsevier B.V. All rights reserved.

Response function measurement of layered type CVD single crystal diamond radiation detectors for 14 MeV neutrons
JH Kaneko, T Teraji, Y Hirai, M Shiraishi, S Kawamura, S Yoshizaki, T Ito, K Ochiai, T Nishitani, T Sawamura
REVIEW OF SCIENTIFIC INSTRUMENTS, 75, 10, 3581, 3584, AMER INST PHYSICS, Oct. 2004, [Peer-reviewed], [Lead author]
English, Scientific journal, Response function measurement of layered-type chemical vapor deposition single crystal diamond radiation detectors for 14 MeV neutrons was carried out. The detector had a layered structure that was composed of a boron-doped diamond layer of 0.5 mum in thickness and a nondoped diamond layer of 20 mum on an inexpensive high pressure and high temperature-type Ib diamond substrate. The detector had energy resolution of 2.6% for 5.5 MeV alpha particles. This experiment was mainly carried out in order to understand the present status of the detector as a 14 MeV neutron spectrometer and an extent of charge trapping. As result, a peak caused by the C-12(n,alpha(0))Be-9 reactions was clearly observed; the best energy resolution of 6% as for a synthetic diamond radiation detector was achieved. Detection efficiency was 3.2x10(-7) counts/unit neutron fluence. However, taking the energy resolution for alpha particles, etc., into account, the energy resolution for 14 MeV neutrons was not so high. Further improvement based on better crystal growth is indispensable. (C) 2004 American Institute of Physics.

Investigation on possibility of neutron electric optical devices based on piezoelectric single crystals
JH Kaneko, Y Otake, H Fujimoto, S Kawamura, M Watanabe, F Fujita, T Sawamura, P Mikula, M Furusaka
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 529, 1-3, 166, 168, ELSEVIER SCIENCE BV, Aug. 2004, [Peer-reviewed], [Lead author]
English, Scientific journal, A principle verification experiment of neutron electric optical devices using piezoelectric single crystals was carried out. This neutron electric optical device can change its d-spacing by applying an electric field to the crystal, which results in change of the Bragg diffraction angle. Although an alpha-quartz has a small piezoelectric strain constant, an alpha-quartz was used in this experiment because characteristics of alpha-quartz are well known and it is easy to obtain high quality and large size single crystals. At first, macroscopic distortion and change of thickness caused by an applied electric field were observed by using laser interferometers. Thus, double crystal diffraction measurement using 4.7 Angstrom cold neutrons was carried out. For these experiments, DC bias voltage was applied to the crystal. As a result, peaks of rocking curves were shifted 14s at 500 V and 2 min at 1000 V from their original positions. These values were approximately one figure larger than the theoretical values; therefore, these results were influenced by macroscopic bending of the crystal. From these results, it can be concluded that the possibility of neutron electric optical devices using not only change of d-spacing but also macroscopic bending of piezoelectric crystal was confirmed. (C) 2004 Elsevier B.V. All rights reserved.

Preliminary results on development of a thin GSO scintillator for neutron science
JH Kaneko, N Susa, S Tsuchida, M Watanabe, S Miura, T Mizuno, Y Yamauchi, M Hashiba, T Oku, A Homma, F Fujita, T Ino, M Furusaka, T Sawamura, HM Shimizu, Y Kiyanagi
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 529, 1-3, 307, 309, ELSEVIER SCIENCE BV, Aug. 2004, [Peer-reviewed], [Lead author]
English, Scientific journal, A thin GSO scintillator was developed aiming at applications for the neutron science. In order to fabricate a large and thin GSO scintillator in the future, fabrication was started from two types of GSO powders. Although several GSO films were fabricated by evaporation techniques, these films did not have luminescence in photo luminescence (PL) spectroscopy. Thus, these samples were annealed up to 1550degreesC. However, it resulted in no luminescence observation. In response to these results, GSO powders were directly annealed; a phenomenon looking like melting and sintering were observed for Gd2Si2O7:Ce at a temperature higher than 1500degreesC. This sample was quasi-transparent and had luminescence at 405 nm in PL spectrum. In addition, this sample was tougher than a GSO single crystal. In conclusion, the prospect of fabrication of a thin GSO scintillator by combination of annealing and mechanical polishing was obtained. (C) 2004 Elsevier B.V. All rights reserved.

D-T neutron skyshine experiments and the MCNP Analysis
Takeo Nishitani, Kentaro Ochiai, Shigeo Yoshida, Ryohei Tanaka, Masashi Wakisaka, Makoto Nakao, Satoshi Sato, Michinori Yamauchi, Jun-Ichi Hori, Masayuki Wada, Akito Takahashi, Jun-Ichi Kaneko, Teruko Sawamura
Journal of Nuclear Science and Technology, 41, 58, 61, 2004
English, Scientific journal, The D-T neutron skyshine experiments were carried out at the Fusion Neutronics Source (FNS) of JAERI with a port at the roof in March 2002 and March 2003. The concrete thickness of the roof and the wall of a FNS target room are 1.15 and 2 m, respectively. The FNS skyshine port with a size of 0.9 × 0.9 m2 was open during the experimental period. The source neutron intensity was -1.7 × 1011 n/s in those skyshine experiments. The highest total dose rate measured was about 0.5 μSv/h at a distance of 30 m from the D-T target point and the dose rate was attenuated to about 0.1 μSv/h at a distance of 100 m and 0.02 μSv/h at a distance of 550 m. Those experimental results were analyzed by Monte Carlo code MCNP-4C with the nuclear data library JENDL-3.2, where the FNS building and the measurement field were modeled with a simplified cylindrical geometry, and the pine forest was modeled by homogenized cell with a height of 10m. The MCNP calculation agreed well both neutron and secondary gamma-ray dose rate distributions. © 2014 Atomic Energy Society of Japan.

Superheated emulsions as high-energy neutron dosemeters
M Das, T Sawamura, M Abe, JH Kaneko, A Homma, F Fujita, S Tsuda, T Nishitani
RADIATION PROTECTION DOSIMETRY, 110, 1-4, 325, 331, OXFORD UNIV PRESS, 2004
English, Scientific journal, Superheated emulsions being inexpensive, easy to fabricate, and having tissue equivalent composition make them as one of the popular neutron dosemeters. One more advantage is that they can be made insensitive to gamma rays by the choice of the sensitive liquid. It is observed that the response of commercially available bubble detector to neutron decreases above 20 MeV while its response is roughly flat in the 0.1-15 MeV region. This restricts its application as a dosemeter to high-energy neutrons. The response of bubble detector from Bubble Technology Industries, has been observed by using Pb-breeder for high-energy neutrons from different facilities in Japan. It is observed that 2-3 cm Pb-breeder is effective in increasing the response of the detector to the nominal value. Theoretical calculation using MCNPX code indicates an increase in neutrons in the energy range of 0.1-10 MeV with Pb-breeder. The present work indicates the possibility of using the bubble detector as a dosemeter to high-energy neutron using a Pb-breeder of proper thickness.

Propagation characteristics of neutrons leaking from the accelerator facilities
M Kitaichi, S Sawamura, M Wakisaka, JH Kaneko, K Ochiai, T Nishitani, T Sawamura
RADIATION PROTECTION DOSIMETRY, 110, 1-4, 731, 738, OXFORD UNIV PRESS, 2004, [Peer-reviewed]
English, Scientific journal, In this study spatial and time distribution of neutrons leaking from Hokkaido University 45 MeV Electron Linac facility have measured and compared with the Monte Carlo simulations. The neutron transport processes inside and outside the facility building has been simulated using MCNP. The neutrons have measured by BF3 counters and He-3 counters with polyethylene moderators up to the distance of 330 in from the facility. The spatial distribution of ambient dose equivalent converted from the counts has been compared with the simulation. The distribution estimated from the counts by the BF3 counter has been shown fairly good agreement with the calculation. The spatial distribution of counts obtained at the 45 MeV Electron Linac facility has been compared with that obtained at the Fusion Neutronics Source (FNS) facility of JAERI. The difference between the propagation characteristics of neutrons leaking from those facilities has been discussed.

Measurement of behavior of charge carriers and investigation into charge-trapping mechanisms in high-purity type-IIa diamond single crystals grown by high-pressure and high-temperature synthesis
JH Kaneko, T Tanaka, Y Tanimura, A Birumati, Y Hirai, M Katagiri, Y Ikeda, T Nishitani, H Takeuchi, T Iida, T Sawamura
NEW DIAMOND AND FRONTIER CARBON TECHNOLOGY, 14, 5, 299, 311, MYU K K, 2004, [Peer-reviewed], [Lead author]
English, Scientific journal, The behavior of charge carriers in type-IIa single diamond crystals grown by high-pressure and high-temperature synthesis was observed using nuclear methods. The drift velocities of holes and electrons were measured by a time-of-flight method using a particles from an Am-241 source. Although the drift velocities of holes and electrons were 6.7 x 10(5) cm/s at 30 kV/cm and 6.5 x 10(5) cm/s at 15 kV/cm, respectively, these values are less than 1/10 of the drift velocities of top-grade, high-purity natural-type IIa diamond single crystals reported elsewhere. In addition, pulse-height spectra, i.e., induced-charge distribution, were measured with light illumination to determine the energy levels of trapping centers, and it was revealed that illumination with red light released trapped electrons. Moreover, it was observed that red light illumination facilitated the quick release of trapped holes. To explain these experimental results, the Fermi level and ionizing ratio of impurities were calculated. Results show that nitrogen works as a trapping center for electrons and boron works as a trapping center for holes; probably this center had trapping and detrapping effects on holes. However, it was confirmed that holes could not play the role of a trapping center for electrons. Moreover, it was revealed that another energy level was required for a trapping center for electrons. To explain all experimental results, an energy level 0.6 eV above the valence band was assumed in addition to the nitrogen and boron impurities. In this case, several ppm of acceptor-like centers are required to function as trapping centers for electrons.

Measurement of radiation skyshine with D-T neutron source
S Yoshida, T Nishitani, K Ochiai, J Kaneko, J Hori, S Sato, M Yamauchi, R Tanaka, M Nakao, M Wada, M Wakisaka, Murata, I, C Kutsukake, S Tanaka, T Sawamura, A Takahashi
FUSION ENGINEERING AND DESIGN, 69, 1-4, 637, 641, ELSEVIER SCIENCE SA, Sep. 2003, [Peer-reviewed]
English, Scientific journal, The D-T neutron skyshine experiments have been carried out at the Fusion Neutronics Source (FNS) of JAERI with the neutron yield of similar to 1.7 x 10(11) n/s. The concrete thickness of the roof and the wall of a FNS target room are 1.15 and 2 in. respectively. The FNS skyshine port with a size of 0.9 x 0.9 m(2) was open during the experimental period. The radiation dose rate outside the target room was measured a maximum distance of 550 in from the D-T target point with a spherical rem-counter. Secondary gamma-rays were measured with high purity Ge detectors and NaI scintillation counters. The highest neutron dose was about 9 x 10(-22) Sv/(source neutron) at a distance of 30 in from the D-T target point and the dose rate was attenuated to 4 x 10(-24) Sv/(source neutron) at a distance of 550 in. The measured neutron dose distribution was analyzed with Monte Carlo code MCNP-4B and a simple line source model. The MCNP calculation overestimates the neutron dose in the distance range larger than 230 m. The line source model agrees well with the experimental results within the distance of 350 m. (C) 2003 Elsevier Science B.V. All rights reserved.

Effect of lead converter on superheated drop detector response to high-energy neutrons
T Sawamura, JH Kaneko, M Abe, M Tamura, Murai, I, A Homma, F Fujita, S Tsuda
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 505, 1-2, 29, 32, ELSEVIER SCIENCE BV, Jun. 2003, [Peer-reviewed]
English, Scientific journal, The response of superheated drop detectors or bubble detectors (BDs) was measured for quasi-monoenergetic neutron beams in the 40-75 MeV range and the effects of a lead-converter enclosing the detector introduced to extend the response to the high-energy region were discussed. The experiments were performed in the quasi-monoenergetic neutron beam field at the AVF cyclotron facility, TAKASAKI Ion Accelerator for Advanced Radiation Application (TIARA) of Japan Atomic Energy Research Institute(JAERI). Monte Carlo calculations by MCNPX code were carried out to estimate the lead-converter effect on neutron spectra in a detector exposed to 40-75 MeV quasi-monoenergetic source neutrons. The calculations indicated an increase in the energy ranges of the neutrons of 0.1-10 MeV and this can be expected to increase the number of bubbles produced in the detector. Experimental results showed that the sensitivity was lowered to about a half the nominal sensitivity and that a 3 cm thick lead-converter could compensate for the sensitivity decrease in the experimental energy region. (C) 2003 Elsevier Science B.V. All rights reserved.

Radiation detector made of a diamond single crystal grown by a chemical vapor deposition method
JH Kaneko, T Tanaka, T Imai, Y Tanimura, M Katagiri, T Nishitani, H Takeuchi, T Sawamura, T Iida
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 505, 1-2, 187, 190, ELSEVIER SCIENCE BV, Jun. 2003, [Peer-reviewed], [Lead author]
English, Scientific journal, The first investigation of a radiation detector made of a diamond single crystal grown by a chemical vapor deposition (CVD) method was successfully carried out. The diamond single crystal, having a size of 2.0 x 2.0 x 0.7 mm(3), was grown by the CVD method and then applied to the detector. The CVD method was able to reduce nitrogen and boron impurities in diamond crystals more effectively than a high-pressure and high-temperature (HP/HT) method. Consequently the detector had high-energy resolution of 0.4% for 5.486 MeV alpha particles from an Am-241 source. The behavior of charge carriers in the detector could not be adequately investigated because the detector had a partial depression layer and strong rectification. Ionization energy of the CVD diamond was determined to be 16.1 eV; this value was higher than that of the HP/HT type IIa diamond, i.e., 13.1 eV. This result shows the potential of CVD diamond single crystals because an ideal diamond should have higher ionization energy than the HP/HT type IIa diamond that had the influence of impurities. (C) 2003 Elsevier Science B.V. All rights reserved.

In situ transmissivity measurements of KU1 quartz in the UV range under 14 MeV neutron irradiation
T Sugie, T Nishitani, S Kasai, J Kaneko, S Yamamoto
JOURNAL OF NUCLEAR MATERIALS, 307, 1264, 1267, ELSEVIER SCIENCE BV, Dec. 2002, [Peer-reviewed]
English, Scientific journal, The transmissivity of KU-1 quartz which is a candidate of the window material for UV and visible spectroscopy in ITER was measured under the irradiation of 14 MeV neutrons up to the fluence of 7.4 x 10(19) n/m(2) in the UV range (200-400 nm) Significant transmission loss was observed in the wavelength range of 200-300 nm. Two absorption peaks were identified: an E'-center at 215 nm and Si(III) defects at 245 nm. The E'-center absorption is much larger than the Si(III) defect absorption. The transmission loss increased with the neutron fluence, decreased during the irradiation breaks and returned almost to the same level as before when the irradiation resumed. This phenomenon indicates that an absorption induced by the neutron irradiation is caused by stable scattering and short lifetime centers. (C) 2002 Elsevier Science B.V. All rights reserved.

Radiation distribution sensing with normal optical fiber
R Naka, K Watanabe, J Kawarabayashi, A Uritani, T Iguchi, N Hayashi, N Kojima, T Yoshida, J Kaneko, H Takeuchi, T Kakuta
IEEE TRANSACTIONS ON NUCLEAR SCIENCE, 48, 6, 2348, 2351, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Dec. 2001, [Peer-reviewed]
English, 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 (Sr-90-Y-90), gamma-rays (Cs-137), 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 X 10(-5)% and 1.2 x 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.

Absolute measurement of D-T neutron flux with a monitor using activation of flowing water
Y Uno, J Kaneko, T Nishitani, F Maekawa, T Tanaka, S Shibata, Y Ikeda, Khripunov, V, C Walker, K Ebisawa, H Takeuchi
FUSION ENGINEERING AND DESIGN, 56-57, 895, 898, ELSEVIER SCIENCE SA, Oct. 2001, [Peer-reviewed]
English, Scientific journal, Neutron activation with water flow based on the (16)O(n, p)(16)N reaction (T(1/2) = 7.13 s) has been proposed for the accurate fusion power monitor with reasonable time resolution in International Thermonuclear Experimental Reactor (ITER)-FEAT. The experiment for validation of the method for determining the neutron flux was carried out at the Fusion Neutronics Source (FNS) facility in Japan Atomic Energy Research Institute (JAERI). The stainless steel (SS316)/Water assembly was utilized to simulate a neutron field in the blanket region of ITER. The closed water loop was laid between the assembly and the shielded measurement area. The gamma -rays from the irradiated water were measured by Bi(4)Ge(3)O(12) scintillator which was similar to 12 m away from the irradiation point. The range of the ow velocity was 2-11 m/s. The neutron spectrum at the probe section in the SS316/Water assembly was calculated by the MCNP-4B code with the FENDL/E-2.0 library. The cross section data of the (16)O(n, p)(16)N reaction was taken from the FENDL/A-2.0 file. The counting response of the BGO detector including the effect of the shielding lead blocks surrounding it was calculated by MCNP-4B. The neutron yield from the water activation has a good agreement with that from associated alpha particle detector. (C) 2001 Elsevier Science B.V. All rights reserved.

Digital waveform analysis for He-3 ionization chamber
J Kawarabayashi, MR Mardiyanto, A Uritani, T Iguchi, J Kaneko, H Takeuchi
IEEE TRANSACTIONS ON NUCLEAR SCIENCE, 48, 3, 527, 529, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Jun. 2001, [Peer-reviewed]
English, Scientific journal, Numerical analyzes on individual pulses from a cylindrical He-3 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 He-3(n, p)T and He-3(n, n)He-3 at the energy region of the He-3 recoil edge was observed.

Neutronics experiments for ITER at JAERI/FNS
C Konno, F Maekawa, Y Kasugai, Y Uno, J Kaneko, T Nishitani, M Wada, Y Ikeda, H Takeuchi
NUCLEAR FUSION, 41, 3, 333, 337, INT ATOMIC ENERGY AGENCY, Mar. 2001, [Peer-reviewed]
English, Scientific journal, A series of fusion neutronics experiments has been performed at the Fusion Neutronics Source facility at Japan Atomic Energy Research Institute as ITER EDA R&D tasks to find ways of dealing with various nuclear problems originating from 14 MeV neutrons in ITER. Recently three groups of experiments were carried out: (1) straight duct streaming experiments, (2) decay heat experiments, and (3) development of a fusion power monitor utilizing activation of water. The straight duct streaming experiments suggest that the calculation accuracy for straight duct streaming analyses in ITER nuclear designs is +/-40%. The decay heat experiments show that the accuracy of the decay heat calculation is within 10% for copper and type 316 stainless steel, while it is similar to 30% for tungsten. It is demonstrated that a fusion power monitor utilizing activation of water is applicable to ITER.

Diamond radiation detector made of an ultrahigh-purity type IIa diamond crystal grown by high-pressure and high-temperature synthesis
T Tanaka, J Kaneko, D Takeuchi, H Sumiya, M Katagiri, T Nishitani, H Takeuchi, T Iida, H Ohkushi
REVIEW OF SCIENTIFIC INSTRUMENTS, 72, 2, 1406, 1410, AMER INST PHYSICS, Feb. 2001, [Peer-reviewed]
English, Scientific journal, Synthetic diamond radiation detectors made of ultrahigh-purity type IIa diamond crystals were developed. The diamond crystals, which were grown by high-pressure and high-temperature synthesis, contained less nitrogen impurity than 0.1 ppm, i.e., 1/10 of conventional type IIa diamond crystals. Since the ultrahigh-purity type IIa diamond crystal was a p-type semiconductor due to a trace impurity of boron, a structure consisting of Schottky and ohmic contacts was adopted for the detectors to suppress an increase in leakage current. For the same purpose, a metal-insulator-semiconductor structure using a chemical vapor deposition diamond insulating layer was adopted for one of the detectors. Plural peaks were observed in the 5.486 MeV alpha energy spectra obtained by the detectors; motion of holes produced the main part of output pulses from the detectors on these measurements. One of the peaks in each spectrum was hardly influenced by light irradiation, even ultraviolet light of 370 nm (3.4 eV), compared with a peak obtained by the conventional type IIa diamond radiation detector. This experimental result indicated that there was a superior part in the crystal where deep energy levels did not exist so much. Although there was no direct evidence, influence of a distribution of the boron impurity in the crystal was expected. On the other hand, electron trapping severely occurred and resulted in loss in charge collection; an effect of the reduction in the nitrogen impurity was not confirmed on the behavior of electrons. (C) 2001 American Institute of Physics.

Study on X-Rays and Neutrons Leaked from a 45 MeV Electron Linac Facility　　　　　　　　　　　　　　　
Sadashi Sawamura, Masatoshi Kitaichi, Ichiro Nojiri, Takuma Yamada, Junichi Kaneko, Teruko Sawamura
J. Korean Asso. Radiat. Prot, 26, 3, 133, 137, 2001, [Peer-reviewed]

Technical feasibility study on a fusion power monitor based on activation of water flow
J Kaneko, Y Uno, T Nishitani, F Maekawa, T Tanaka, Y Shibata, Y Ikeda, H Takeuchi
REVIEW OF SCIENTIFIC INSTRUMENTS, 72, 1, 809, 813, AMER INST PHYSICS, Jan. 2001, [Peer-reviewed], [Lead author]
English, Scientific journal, As a part of development of nuclear instrumentation for the international thermonuclear experimental reactor (ITER), technical feasibility of a fusion power monitor based on activation of water flow was studied. The fusion power monitor determines D-T neutron yield, i.e., fusion power, by measuring 6.1 and 7.1 MeV gamma rays accompanied by disintegration of N-16 nuclei that are produced by the O-16(n,p) N-16 reactions with 14 MeV neutrons in water. The fusion power monitor consists of a water pipe loop laid from the first wall to the outside of the bioshield and a gamma -ray detector, e.g., a BGO scintillator. Fusion power can be measured in an absolute value by this monitor similar to a neutron activation method with a pneumatic tube system; in addition, this monitor has a feature that continuously measures the fusion power with time resolution faster than 1 s. This monitor also has other excellent features in terms of long-term stability, sensitivity only for D-T neutrons and being maintenance free. In order to confirm the technical feasibility of the fusion power monitor based on activation of water flow, experiments for dependence of N-16 gamma -ray yield on the velocity of water flow and for time response were carried out. It was found that the time response was described in a turbulent flow model, and time resolution of 50 ms that fully satisfied the time resolution of 100 ms required from plasma diagnostics was achieved. Furthermore, detection sensitivity of the fusion power monitor when it is applied to the ITER was estimated based on the experimental results; it was determined that the monitor had sufficiently high sensitivity. (C) 2001 American Institute of Physics.

Determination of metallic impurities in high-purity type IIa diamond grown by high-pressure and high-temperature synthesis using neutron activation analysis
J Kaneko, C Yonezawa, Y Kasugai, H Sumiya, T Nishitani
DIAMOND AND RELATED MATERIALS, 9, 12, 2019, 2023, ELSEVIER SCIENCE SA, Dec. 2000, [Peer-reviewed], [Lead author]
English, Scientific journal, Metallic impurities in high-purity type IIa and conventional type To diamond single crystals grown by high-pressure and high-temperature (HPHT) synthesis were determined by neutron activation analysis using thermal neutrons. Metallic impurities of Fe, Co, Cr and other minor elements were detected in the high-purity type IIa diamond crystal. The typical quantities of these metallic impurities were a few ppb. The influence of these metallic impurities on the electrical properties of the type IIa diamond crystal was practically negligible compared with nitrogen and boron impurities behaving as a donor and an acceptor, respectively. In addition to the impurities detected in the type IIa diamond crystal, Ni impurities of several hundreds of ppb were detected in conventional type Ib diamond crystals. A difference in molten metal solvents used in the synthesis of each diamond crystal resulted in the difference in metallic impurities. (C) 2000 Elsevier Science B.V. All rights reserved.

High-temperature operation of a radiation detector made of a type IIa diamond single crystal synthesized by a HP/HT method
Y Tanimura, J Kaneko, M Katagiri, Y Ikeda, T Nishitani, H Takeuchi, T Iida
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 443, 2-3, 325, 330, ELSEVIER SCIENCE BV, Apr. 2000, [Peer-reviewed]
English, Scientific journal, Characteristics of a synthetic diamond radiation detector in high-temperature environments up to 196 degrees C were investigated. The radiation detector was made of a high-purity type IIa diamond single crystal synthesized by a high-pressure and high-temperature (HP/HT) method. In order to suppress a strong increase in leakage current in a high-temperature environment, a surface barrier structure composed of Schottky and ohmic contacts was adopted. The detector operated as an energy spectrometer for 5.486 MeV alpha particles up to 156 degrees C. The peak due to the alpha particles obtained at 68 degrees C slightly shifted to the higher-energy side compared with the same peak obtained at 25 degrees C; furthermore, the energy resolution of these peaks was improved with the increase in the detector temperature. Effects of trapping and detrapping on holes were suppressed by thermal excitation, and this resulted in an improvement in collection efficiency of charge carriers. With a further increase in the detector temperature, loss of charge carriers became more significant. Finally, operation of the detector was prevented at 196 degrees C by a polarization phenomenon caused by accumulation of space charge in the detector. (C) 2000 Elsevier Science B.V. All rights reserved.

Stimulated emission and exciton complex in some insulator crystals irradiated by heavy ions
K Kimura, J Kaneko, S Sharma, N Itoh
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 154, 1-4, 318, 324, ELSEVIER SCIENCE BV, Jun. 1999, [Peer-reviewed]
English, Scientific journal, Excitation-density dependent luminescence, its decay curves, and time-resolved spectra were measured for ion irradiated alpha-alumina, RbI and CsCl at various temperatures and with a time resolution of 100 ps. Contrary to the usual results of scintillation research, we found that some insulator crystals show excitation-density enhanced stimulated emission through distant interaction between excited states (excitons) and through photons emitted, and found a new 100 ps-lived luminescence band. The manner of excitation-density and temperature dependence of the luminescence efficiency and decay rate of this new band suggests the formation of the exciton complex and further of the electron-hole plasma. (C) 1999 Elsevier Science B.V. All rights reserved.

High-energy resolution spectrometer with proportional counter and Si-detector telescope type for 14 MeV neutrons in plasma diagnostics
C Mori, J Gotoh, A Uritani, H Miyahara, Y Ikeda, Y Kasugai, J Kaneko, M Sasao, Y Sakuma, K Kudo, N Takeda, T Iida
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 422, 1-3, 75, 78, ELSEVIER SCIENCE BV, Feb. 1999, [Peer-reviewed]
English, Scientific journal, A new type of fast neutron spectrometer composed of a CH4 proportional counter and a Si semiconductor detector which is called the counter telescope type was constructed for plasma-temperature diagnostics. The counting gas CH4 is used as a converter of neutrons to protons. Since the energy loss of the proton in the converter CH4 can be fairly precisely measured with the proportional counter, the energy resolution for the proton is high, so that a good energy resolution for neutrons is obtained. The energy resolution of the spectrometer itself excluding the energy spread of the D-T 14 MeV neutrons was 1.7% which seems to be the best so far, and the detection efficiency was 1 x 10(-6). If better energy resolution is preferable, even 0.5% is obtained and the efficiency in this case is 4 x 10(-8). (C) 1999 Elsevier Science B.V. All rights reserved.

Development of a synthetic diamond radiation detector with a boron doped CVD diamond contact
J Kaneko, M Katagiri, Y Ikeda, T Nishitani
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 422, 1-3, 211, 215, ELSEVIER SCIENCE BV, Feb. 1999, [Peer-reviewed], [Lead author]
English, Scientific journal, A boron doped CVD diamond contact was applied to a diamond radiation detector for suppressing a polarization phenomenon. A boron doped CVD diamond layer was grown on a synthetic type IIa single crystal diamond; it was then used as a contact. The contact was completely free from radiation damage which is unavoidable in a contact made by an ordinary ion implantation technique. An energy resolution of 0.39% for 5.486 MeV alpha particles was achieved. A steady counting rate higher than 50 cps for alpha particles was confirmed by the developed detector. It is proposed that the boron doped CVD diamond contact functioned as a blocking contact on this detector. (C) 1999 Elsevier Science B.V. All rights reserved.

Response function measurement of a synthetic diamond radiation detector for 14 MeV neutrons
J Kaneko, Y Ikeda, T Nishitani, M Katagiri
REVIEW OF SCIENTIFIC INSTRUMENTS, 70, 1, 1100, 1103, AMER INST PHYSICS, Jan. 1999, [Peer-reviewed], [Lead author]
English, Scientific journal, The response function of a diamond radiation detector using a synthetic type IIa single diamond crystal for 14 MeV neutrons was measured. There was severe trapping of electrons in the synthetic diamond crystals used in this study. Accordingly, a prototype diamond radiation detector using the synthetic type IIa single diamond whose thickness was 0.1 mm was used with high bias voltage up to 1000 V, i.e., electric field of 100 kV/cm. The measurement resulted in the first observation of a 14 MeV neutron peak corresponding to C-12(n, alpha)Be-9 reactions by a synthetic diamond radiation detector. Energy resolution of the prototype detector for 14 MeV neutrons was 9%. Experimental detection efficiency of the detector was consistent with calculated detection efficiency. Synthetic diamond crystals which do not have trapping of charge carriers are indispensable in order to improve energy resolution for 14 MeV neutrons. (C) 1999 American Institute of Physics. [S0034-6748(99)53301-7].

Stimulated emission at 326 nm and an ultra fast luminescence component by ion irradiation of α-alumina
KIMURA K, KANEKO J, SHARMA S, HONG W, ITOH N
Phys. Rev. B, 60, 18, 12626, 12634, 1999, [Peer-reviewed]

Extremely fast decay component of UV luminescence from 2-MeV/amu ion irradiated alumina
K Kimura, W Hong, J Kaneko, N Itoh
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 141, 1-4, 425, 430, ELSEVIER SCIENCE BV, May 1998, [Peer-reviewed]
English, Scientific journal, Luminescence spectra and their decay curves are measured for alpha-alumina irradiated by various ions and at various temperatures. The luminescence spectra show several bands in addition to the 3.8-eV band being well-known electron and photon irradiation. The decay curves and time-resolved spectra show enhanced decay of the 3,8-eV band and a new extremely fast decay component at about 400 nm which has a half lifetime of 100 ps or less. (C) 1998 Published by Elsevier Science B.V. All rights reserved.

Fusion neutronic source deuterium-tritium neutron spectrum measurements using natural diamond detectors
AV Krasilnikov, J Kaneko, M Isobe, F Maekawa, T Nishitani
REVIEW OF SCIENTIFIC INSTRUMENTS, 68, 4, 1720, 1724, AMER INST PHYSICS, Apr. 1997, [Peer-reviewed]
English, Scientific journal, Two natural diamond detectors (NDDs) operating at room temperature were used for Fusion Neutronics Source (FNS) deuterium-tritium (DT) neutron spectra measurements at different points around the tritium target and for different deuteron beam energies, Energy resolution of both NDDs were measured, with values 1.95% and 2.5%. Due to the higher energy resolution of one of the two NDDs studied it was possible to measure the shape of the DT neutron energy distribution and its broadening due to deuteron scattering inside the target. The influence of pulse pileup on the energy resolution of the combined system (NDD+electronics) at count rates up to 3.8X10(5) counts/s was investigated, A 3.58% energy resolution for the spectrometric system based on NDD and a 0.25 mu s shaping time amplifier has been measured at a count rat of 5.7X10(5) counts/s. It is shown that special development of a fast pulse signal processor is necessary for NDD based spectrometry at count rates of approximately 10(6) counts/s. (C) 1997 American Institute of Physics.

First measurements of triton burnup neutron spectra using a natural diamond detector on JT-60U
M Isobe, T Nishitani, AV Krasilnikov, J Kaneko, M Sasao
FUSION ENGINEERING AND DESIGN, 34-35, 573, 576, ELSEVIER SCIENCE SA, Mar. 1997, [Peer-reviewed]
English, Scientific journal, A natural diamond detector (NDD) is one of the candidates for the D-T neutron spectrometer in the International Thermonuclear Experimental Reactor since it has a high energy resolution, a high radiation resistance and a very compact size. The characteristic performance of NDD as a D-T neutron spectrometer was examined at the FNS neutron generator. The NDD indicated the energy resolution of 1.95% to 14.1 MeV neutrons. In order to obtain the information of the triton slowing-down, the NDD was applied to the deuterium discharges of the JT-60U tokamak. By accumulating the data of several shots, the change of the pulse height spectrum suggesting the slowing-down of tritons was observed after neutral beam turn-off. (C) 1997 Elsevier Science S.A.

Development of 14 MeV neutron spectrometer for fusion experimental reactor
T Iguchi, E Takada, M Nakazawa, J Kaneko, T Nishitani, T Matoba, Y Ikeda
FUSION ENGINEERING AND DESIGN, 34-35, 585, 589, ELSEVIER SCIENCE SA, Mar. 1997, [Peer-reviewed]
English, Scientific journal, A 14 MeV neutron spectrometer suitable for an ITER-like fusion reactor is conceptually designed on the basis of a recoil proton counter telescope method in oblique scattering geometry. To verify the principle and basic performance of the detector concept, preliminary experiments are made for a prototype detector system, where the detector responses are measured to 14 MeV neutrons produced from an accelerator deuterium-tritium (DT) neutron source and compared with the calculated ones. The comparison results show reasonably good agreement and demonstrate the possibility of energy resolution of 2.5% in full width at half maximum for 14 MeV neutron spectrometry. (C) 1997 Elsevier Science S.A.

A directional neutron detector based on a recoil proton telescope for neutron emission profile monitor
J Kaneko, M Katagiri, Y Ikeda, K Ara, T Iguchi, M Nakazawa
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 385, 1, 157, 160, ELSEVIER SCIENCE BV, Jan. 1997, [Peer-reviewed], [Lead author]
English, Scientific journal, A directional neutron detector based on a recoil proton telescope was investigated by experimental approach. The detector showed a directionality not only for 14-MeV neutrons but also for fission and 2.4-MeV neutrons. Due to a good rise-time pulse-shape discrimination capability of a CsI(Tl) scintillator, a recoil proton energy spectrum was clearly observed in high gamma-ray background. At a detector angle of 21 degrees with respect to the neutron incident direction, the counts corresponding to the high energy neutron became a half of those at 0 degrees. A major source for reducing the signal-to-noise ratio was identified to be the energetic protons via the (n, p) reaction in the CsI(Tl) scintillator.

Diamond radiation detector using a synthetic IIa type mono-crystal
J Kaneko, M Katagiri
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 383, 2-3, 547, 548, ELSEVIER SCIENCE BV, Dec. 1996, [Peer-reviewed], [Lead author]
English, Scientific journal, A diamond radiation detector using a synthetic IIa type mono-crystal was developed. An energy resolution of 0.81%, 45 keV, was achieved for 5.486 MeV alpha particles in a vacuum environment. The ionization energy, epsilon(Diamond), WBS estimated as 13.07 eV by calibration with a silicon surface barrier detector. On a preamplifier output signal, a trapping and detrapping effect on holes was observed.

CONCEPTUAL DESIGN OF NEUTRON DIAGNOSTIC SYSTEMS FOR FUSION EXPERIMENTAL REACTOR
T IGUCHI, J KANEKO, M NAKAZAWA, T MATOBA, T NISHITANI, S YAMAMOTO
FUSION ENGINEERING AND DESIGN, 28, 1/4, 689, 698, ELSEVIER SCIENCE SA, Mar. 1995, [Peer-reviewed]
English, Scientific journal, Neutron measurement in fusion experimental reactors is very important for burning plasma diagnostics and control, monitoring of irradiation effects on device components, neutron source characterization for in-situ engineering tests etc. A conceptual design of neutron diagnostic systems for an International Thermonuclear Experimental Reactor (ITER)-like fusion experimental reactor is made, which consists of a neutron yield monitor, a neutron emission profile monitor and a 14 MeV neutron spectrometer. Each of them is based on a unique idea to meet the required performances for full power conditions assumed at ITER operation. The final design results and expected performances of the promising neutron diagnostic systems are presented together with their critical design issues.

The 8th International Conference on Rapidly Quenched and Metastable Materials
KANEKO Junichi
Journal of Japan Institute of Light Metals, 44, 1, 67, 68, The Japan Institute of Light Metals, 1994

Challenge for Development of New Materials
KANEKO JUNICHI
Sen-ito Kogyo, 48, 6, P333, P335, The Society of Fiber Science and Technology, Japan, 1992

ASM International Conference on Structural Application of Mechanical Alloying
KANEKO Junichi
Journal of Japan Institute of Light Metals, 40, 8, 649, 650, The Japan Institute of Light Metals, 1990

Internationalization of JILM
KANEKO Junichi
Journal of Japan Institute of Light Metals, 39, 3, 252, 253, The Japan Institute of Light Metals, 1989

Li₂CaSiO₄:Euの合成とその発光特性
張楚明, 樋口幹雄, 鱒渕友治, 金子純一, セラミックス基礎科学討論会講演要旨集, 59th (CD-ROM), 2021

Growth of GdVO₄:Eu single crystals and their scintillation properties for beta-ray
樋口幹雄, 松岡みのり, 錦戸文彦, 山谷泰賀, 武田隆史, 鱒渕友治, 金子純一, 日本セラミックス協会秋季シンポジウム講演予稿集(Web), 34th, 2021

科学解説 単結晶ダイヤモンドの欠陥制御とデバイス安定化技術
大曲 新矢, 小林 篤史, 坪内 信輝, 梅沢 仁, 花田 尊徳, 金子 純一, 山田 英明, New diamond = ニューダイヤモンド, 36, 4, 3, 9, Oct. 2020
ニューダイヤモンドフォーラム, Japanese

Development of diamond neutron detector
金子純一, 平野慎太郎, 田中真伸, 日本原子力学会秋の大会予稿集(CD-ROM), 2020, 2020

Purification of raw material and single crystal growth in a high vacuum atmosphere for practical application of TlBr semiconductor γ-ray detector
長谷川達也, 山石直也, 星川尚久, 金子純一, 樋口幹雄, 人見啓太郎, 結晶成長国内会議予稿集(CD-ROM), 49th, 2020

Float zone growth of GdVO₄:Eu single crystals for β-ray imaging
松岡みのり, 樋口幹雄, 鱒渕友治, 錦戸文彦, 山谷泰賀, 武田隆史, 金子純一, 結晶成長国内会議予稿集(CD-ROM), 49th, 2020

Development of Diamond thermal neutron detector for high temperature operation
平野慎太郎, 金子純一, 伊藤彰悟, 茶谷原昭義, 花田尊徳, 渡邊幸志, 梅沢仁, 竹内大輔, 日本原子力学会北海道支部研究発表会講演要旨集, 37th (CD-ROM), 2020

Improvement of Energy Resolution in Thallium Bromo-Chloride Detectors
人見啓太朗, 野上光博, 小野寺敏幸, 錦戸文彦, 山谷泰賀, 金子純一, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 81st, 2020

TlBr単結晶の大型・高品質化に向けた原料精製プロセスの改良
山石直也, 金子純一, 中村憲法, 長谷川達也, 樋口幹雄, 人見啓太朗, 長野宣道, 野上光博, 日本原子力学会春の年会予稿集(CD-ROM), 2019, 2019

過酷事故対応原子炉用電子デバイスへの適用に向けた高温動作電子部品の開発
三好洋紀, 金子純一, 花田尊徳, 樋口幹雄, 山脇大造, 梅沢仁, 日本原子力学会春の年会予稿集(CD-ROM), 2019, 2019

ダイヤモンド半導体の重粒子に対する応答の研究
上野遥, 松本晴久, 神谷浩紀, 金子純一, 平野慎太郎, 濱野毅, 北村尚, 量子科学技術研究開発機構研究報告書(Web), 13, 2019

ミニマルファブを活用したダイヤモンドSBDの試作と評価
花田尊徳, 梅沢仁, 大曲新矢, 竹内大輔, 根本一正, 根本一正, KHUMPUANG Sommawan, KHUMPUANG Sommawan, 原史朗, 原史朗, 金子純一, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 80th, 2019

ダイヤモンド半導体の重粒子に対する応答の研究
上野遥, 松本晴久, 金子純一, 平野慎太郎, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 79th, 2018

γ線計測用常温動作半導体検出器用TlBr単結晶の大型・高品質化に向けた試み
中村憲法, 金子純一, 山石直也, 長谷川達也, 樋口幹雄, 人見啓太朗, 長野宣道, 結晶成長国内会議予稿集(CD-ROM), 47th, 2018

LiZnBO₃:Mnの合成と中性子イメージングへの応用
川又俊介, 樋口幹雄, 金子純一, 竹谷篤, 小林知洋, 若林泰生, 大竹淑恵, 三浦章, 忠永清治, 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 31st, 2018

大面積(Gd,La)₂Si₂O₇:Ce多結晶薄板の作製とその対アルファ線シンチレーション特性
福島光, 樋口幹雄, 金子純一, 三浦章, 忠永清治, セラミックス基礎科学討論会講演要旨集, 56th, 2018

ダイヤモンド半導体の重粒子に対する応答の研究
上野遥, 松本晴久, 神谷浩紀, 金子純一, 平野慎太郎, 小林進悟, 量子科学技術研究開発機構研究報告書(Web), 8, 2018

Development of Synthetic Diamond Radiation Detector for Neutron Plasma Diagnostics
金子純一, 波紋, 27, 1, 2017

α線計測用GPSシンチレータプレートの性能向上の試み
大西将矢, 金子純一, 鍋田志生, 樋口幹雄, 森下祐樹, 井崎賢治, 山本誠一, 石橋浩之, 日本原子力学会北海道支部研究発表会講演要旨集, 34th, 2017

GPS系シンチレータの開発とその応用
金子純一, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 64th, 2017

単結晶ダイヤモンドを用いた測定器の開発及び評価
原明日翔, 田中真伸, 田中真伸, 金子純一, 平野慎太郎, 水越司, 西口創, 嶋岡毅紘, 山崎聡, 牧野俊晴, 小泉聡, 上殿明良, 八井崇, 三原智, 田中秀治, 田中秀治, 佐波俊哉, 萩原雅之, 吉田光宏, 橋本義徳, 岸本俊二, 岸本俊二, 小嶋健児, 小嶋健児, 大友季哉, 大下英敏, 瀬谷智洋, 日本物理学会講演概要集(CD-ROM), 72, 1, 2017

8mm角CVDダイヤモンド基板上にホモエピタキシャル成長した試料の電荷キャリア輸送特性
金子純一, 平野慎太郎, 嶋岡毅紘, 新名宏章, 坪田雅功, 水越司, 山本航平, 茶谷原昭義, 杢野由明, 梅沢仁, 小泉均, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 64th, 2017

8mm角CVDダイヤモンド単結晶基板上にホモエピタキシャル成長させた試料の電荷キャリア輸送特性評価
平野慎太郎, 金子純一, 嶋岡毅紘, 新名宏章, 坪田雅功, 伊藤彰悟, 茶谷原昭義, 杢野由明, 梅沢仁, 日本原子力学会秋の大会予稿集(CD-ROM), 2017, 2017

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスに関する研究開発
金子純一, 原子力システム開発・原子力基礎基盤戦略研究イニシアティブ共同成果報告会(Web), 2016, 2017

ダイヤモンド半導体の宇宙放射線用被ばく線量計への応用に関する研究
上野遥, 松本晴久, 金子純一, 平野慎太郎, 小林進悟, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 78th, 2017

ダイヤモンド半導体の重粒子に対する応答の研究
上野遥, 松本晴久, 神谷浩紀, 松崎乃里子, 金子純一, 平野慎太郎, 藤井雅之, 小林進悟, 量子科学技術研究開発機構研究報告書(Web), 6, 2017

α線に対する単結晶CVDダイヤモンド放射線検出器のFano因子評価
嶋岡毅紘, 金子純一, 佐藤優樹, 坪田雅功, 新名宏明, 茶谷原昭義, 渡邊幸志, 梅澤仁, 杢野由明, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 63rd, ROMBUNNO.21P-W810-4, 03 Mar. 2016
Japanese

9th International Conference on New Diamond and Nano Carbons-NDNC2015 Preface
Shinichi Shikata, Atsushi Hirata, Fumio Kokai, Junichi H. Kaneko, Kenji Watanabe, Mutsuko Hatano, Takako Nakamura, DIAMOND AND RELATED MATERIALS, 63, 1, 1, Mar. 2016
ELSEVIER SCIENCE SA, English, Others

n型ダイヤモンド薄膜およびダイヤモンドデバイスの耐X線・γ線特性
大谷亮太, LIAO Meiyong, 上野克宜, 佐々木敬介, 田所孝広, 坪田雅功, 金子純一, 小泉聡, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 63rd, 2016

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスの開発(9)ダイヤモンド放射線検出器のX線耐性
坪田雅功, 金子純一, 嶋岡毅紘, 新名宏章, 茶谷原昭義, 加藤有香子, 梅沢仁, 日本原子力学会春の年会予稿集(CD-ROM), 2016, 2016

α線計測用GPS系シンチレータプレートの性能と生産性向上の試み
大西将矢, 金子純一, 鍋田志生, 樋口幹雄, 森下祐樹, 井崎賢二, 山本誠一, 石橋浩之, 日本原子力学会秋の大会予稿集(CD-ROM), 2016, 2016

単結晶ダイヤモンドを用いた測定器の開発及び評価
原明日翔, 田中真伸, 田中真伸, 金子純一, 平野慎太郎, 水越司, 西口創, 嶋岡毅紘, 山崎聡, 牧野俊晴, 小泉聡, 上殿明良, 八井崇, 三原智, 田中秀治, 田中秀治, 佐波俊哉, 萩原雅之, 吉田光宏, 橋本義徳, 岸本俊二, 岸本俊二, 小嶋健児, 小嶋健児, 大友季哉, 大下英敏, 瀬谷智洋, 日本物理学会講演概要集(CD-ROM), 71, 2, 2016

透光性LiYSiO₄:Ce多結晶薄板の作製とそのシンチレーション特性
豊田紗希, 樋口幹雄, 金子純一, 三浦章, 忠永清治, 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 29th, 2016

La置換Gd₂Si₂O₇:Ceの反応焼結とそのシンチレーション特性
福島光, 樋口幹雄, 和氣嵩暁, 金子純一, 三浦章, 忠永清治, 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 29th, 2016

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスに関する研究開発
金子純一, 原子力システム開発・原子力基礎基盤戦略研究イニシアティブ共同成果報告会(Web), 2015, 2016

Fano factor evaluation of single-crystal diamond detector produced by lift-off method
嶋岡毅紘, 金子純一, 佐藤優樹, 坪田雅功, 新名宏明, 茶谷原昭義, 渡邊幸志, 梅澤仁, 杢野由明, 日本原子力学会北海道支部研究発表会講演要旨集, 33rd (CD-ROM), 2016

DT中性子エネルギースペクトロメータ応用を目指した単結晶CVDダイヤモンドの14MeV中性子に対する応答関数評価
嶋岡毅紘, 金子純一, 新名宏章, 坪田雅功, 茶谷原昭義, 渡邊幸志, 梅澤仁, 鹿田真一, 落合謙太郎, 磯部光孝, 長壁正樹, 日本原子力学会春の年会予稿集(CD-ROM), 2015, ROMBUNNO.N34, 05 Mar. 2015
Japanese

位置検出・エネルギー弁別型放射線検出装置用大面積GPS:Ce焼結体シンチレータプレートの開発
鍋田志生, 金子純一, 坪田陽一, 東井宏平, 西方真美, 樋口幹雄, 嶋岡毅紘, 森下祐樹, 井崎賢治, 山本誠一, 日本原子力学会春の年会予稿集(CD-ROM), 2015, 2015

CVDダイヤモンドにおける電荷キャリア輸送特性のアニールによる改善
新名宏章, 金子純一, 坪田雅功, 嶋岡毅紘, 樋口幹雄, 茶谷原昭義, 渡邊幸志, 梅沢仁, 鹿田真一, 日本原子力学会春の年会予稿集(CD-ROM), 2015, 2015

ワイドギャップ半導体を使用した半導体検出器の特性評価
田中真伸, 田中真伸, 牧野高紘, 嶋岡毅紘, 新名章宏, 市川温子, 大島武, 小野田忍, 金子純一, 斉藤正俊, 斉藤正俊, 島崎昇一, 島崎昇一, 土田秀一, 身内賢太朗, 身内賢太朗, 村上武, 村上武, 星乃紀博, 山本和弘, 日本物理学会講演概要集(CD-ROM), 70, 1, 2015

Development of a radiation measurement system based on radiation and heat resistant materials
金子純一, 応用物理, 84, 7, 2015

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスの開発(8)ダイヤモンド放射線検出器の高温特性 3
坪田雅功, 金子純一, 嶋岡毅紘, 新名宏章, 上野克宜, 田所孝広, 茶谷原昭義, 渡邊幸志, 日本原子力学会秋の大会予稿集(CD-ROM), 2015, 2015

LiCaBO₃:Ceの合成とその蛍光特性
豊田紗希, 樋口幹雄, 坪田陽一, 金子純一, 忠永清治, 結晶成長国内会議予稿集(CD-ROM), 45th, 2015

液相焼結による透光性Gd₂Si₂O₇:Ce薄板の作製とその対α線シンチレーション特性
西方真美, 樋口幹雄, 坪田陽一, 金子純一, 山本誠一, 三浦章, 忠永清治, 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 28th, 2015

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスの開発(4)既存検出器の性能評価と性能改善に向けたアプローチ
坪田雅功, 金子純一, 嶋岡毅紘, 宮崎大二郎, 茶屋原昭義, 梅沢仁, 小泉均, 鹿田真一, 日本原子力学会春の年会予稿集(CD-ROM), 2014, 2014

ダイヤモンド検出器の電荷キャリア輸送特性に対する生成キャリア密度の影響
嶋岡毅紘, 金子純一, 青柳秀樹, 佐竹良太, 宮崎大二郎, 青木毅, 深見健二, 鈴木伸介, 満田史織, 茶谷原昭義, 渡邊幸志, 梅沢仁, 鹿田真一, 日本原子力学会春の年会予稿集(CD-ROM), 2014, 2014

TSSG法により合成したGd₂Si₂O₇系単結晶シンチレータの高温環境下での発光特性評価
坪田陽一, 金子純一, 樋口幹雄, 石橋浩之, 皆川萌, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 61st, 2014

位置検出・エネルギー弁別型放射線検出装置用大面積GPS:Ce焼結体シンチレータプレートの開発
鍋田志生, 金子純一, 坪田陽一, 東井宏平, 西方真美, 樋口幹雄, 嶋岡毅紘, 森下祐樹, 井崎賢治, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 75th, 2014

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスの開発(5)ダイヤモンド放射線検出器の高温特性2
坪田雅功, 金子純一, 嶋岡毅紘, 宮崎大二郎, 上野克宜, 田所孝広, 茶谷原昭義, 梅沢仁, 桑原均, 小泉均, 鹿田真一, 日本原子力学会秋の大会予稿集(CD-ROM), 2014, 2014

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスの開発(7)単結晶ダイヤモンド検出器の耐放射線性及び耐熱性の評価
上野克宜, 田所孝広, 佐々木敬介, 桑原均, 坪田雅功, 金子純一, 日本原子力学会秋の大会予稿集(CD-ROM), 2014, 2014

高温環境下におけるダイヤモンド放射線検出器の動作特性評価
金子純一, 坪田雅功, 宮崎大二郎, 上野克宜, 田所孝広, 茶谷原昭義, 梅沢仁, 渡邊幸志, 小泉均, 桑原均, 鹿田真一, 小泉聡, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 75th, 2014

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスの開発(6)単結晶ダイヤモンド検出器の基礎特性評価と信頼性評価
佐々木敬介, 桑原均, 上野克宜, 田所孝広, 坪田雅功, 金子純一, 日本原子力学会秋の大会予稿集(CD-ROM), 2014, 2014

SIMS測定下限領域における窒素低減がダイヤモンド中の電荷キャリア輸送特性に与える影響
新名宏章, 大西将矢, 坪田雅功, 金子純一, 嶋岡毅紘, 宮崎大二郎, 茶屋原昭義, 梅沢仁, 小泉均, 鹿田真一, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 75th, 2014

ダイヤモンドpin放射線検出器の試作
大谷亮太, 山本卓, 田所孝広, 上野克宜, 佐々木敬介, 桑原均, 坪田雅功, 金子純一, 小泉聡, 小泉聡, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 75th, 2014

単結晶CVDダイヤモンド検出器の高速点火方式慣性核融合における中性子燃焼履歴モニタ応用の試み
嶋岡毅紘, 金子純一, 有川安信, 磯部光孝, 坪田雅功, 長井隆浩, 小島完興, 安部勇輝, 坂田匠平, 藤岡慎介, 中井光男, 白神宏之, 畦地宏, 茶谷原昭義, 梅澤仁, 鹿田真一, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 75th, 2014

(Y,Gd)₂Si₂O₇系単結晶シンチレータの高温環境下での発光特性評価
坪田陽一, 金子純一, 樋口幹雄, 石橋浩之, 皆川萌, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 75th, 2014

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスの開発
金子純一, 小泉聡, 鹿田真一, 桑原均, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 61st, 2014

SiO₂をセルフフラックスとしたGd₂Si₂O₇:Ceの液相焼結とその対α線シンチレーション特性
西方真美, 樋口幹雄, 植田あき, 坪田陽一, 金子純一, 忠永清治, 石橋浩之, 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 27th, 2014

Gd₂Si₂O₇:Ce多結晶における粒成長とその対α線シンチレーション特性
西方真美, 樋口幹雄, 植田あき, 坪田陽一, 金子純一, 石橋浩之, 忠永清治, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 75th, 2014

GPS焼結体に対する種々の添加物探索とそのα線に対するシンチレーション特性
皆川萌, 金子純一, 坪田陽一, 樋口幹雄, 西方真美, 石橋浩之, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 75th, 2014

Ceドープ希土類ピロケイ酸塩単結晶の合成とそのシンチレーション特性
樋口幹雄, 矢尾真人, 坪田陽一, 金子純一, 結晶成長国内会議予稿集(CD-ROM), 44th, 2014

オフ角制御済みIIa基板上に合成した単結晶CVDダイヤモンドの14MeV中性子に対する応答関数評価
嶋岡毅紘, 金子純一, 新名宏章, 坪田雅功, 茶谷原昭義, 渡邊幸志, 梅澤仁, 鹿田真一, 落合謙太郎, 磯部光孝, 長壁正樹, 日本原子力学会北海道支部研究発表会講演要旨集, 32nd, 2014

医療用X線計測応用を目指したTbドープGd₂Si₂O₇の合成と発光特性評価
皆川萌, 金子純一, 坪田陽一, 樋口幹雄, 西方真美, 石橋浩之, 日本原子力学会北海道支部研究発表会講演要旨集, 32nd, 2014

La-GPS:Ceシンチレータの発光特性のLa濃度依存性
和氣嵩暁, 金子純一, 坪田陽一, 皆川萌, 樋口幹雄, 石橋浩之, 日本原子力学会北海道支部研究発表会講演要旨集, 32nd, 2014

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスに関する研究開発
金子純一, 原子力システム開発・原子力基礎基盤戦略研究イニシアティブ共同成果報告会(Web), 2013, 2014

Development of Neutron Measurement Systems for Study of High-Energy Particle Physics　　　　　　　　　　　　　　　
Uritani, A, Iguchi, T, Kawarabayashi, J, Watanabe, K, Tomita, H, Yamazaki, A, Nakamura, M, Nakano, T, Morishima, K, Sasao, M, Nishitani, T, Ochiai, K, Shinohara, T, Kondo, T, Ishikawa, K, Takada, E, Kaneko, J.H, NIFS Annual Report Apr.2012 - Mar.2013, 2012, 243, Nov. 2013
English

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスの開発-(1)開発計画概要-
金子純一, 小泉聡, 鹿田真一, 桑原均, 小泉均, 坪田雅功, 嶋岡毅弘, MEIYONG Liao, 寺地徳行, 梅沢仁, 渡邊幸志, 杢野由明, 坪内信輝, 日本原子力学会春の年会予稿集(CD-ROM), 2013, 2013

TSSG法によるGPS:Ce単結晶シンチレータの合成とそのシンチレーション特性
坪田陽一, 金子純一, 樋口幹雄, 石橋浩之, 西山修輔, 嶋岡毅紘, 東井宏平, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 60th, 2013

大面積GPSシンチレータプレートのα線ダストモニタとしての性能評価
東井宏平, 金子純一, 井崎賢二, 嶋岡毅紘, 坪田陽一, 森下祐樹, 樋口幹雄, 日本原子力学会秋の大会予稿集(CD-ROM), 2013, 2013

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスの開発-(3)単結晶ダイヤモンド検出器のγ線応答及び計測安定性の評価
上野克宜, 田所孝広, 佐々木敬介, 桑原均, 金子純一, 日本原子力学会秋の大会予稿集(CD-ROM), 2013, 2013

過酷事故対応を目指した原子炉用ダイヤモンド半導体デバイスの開発(2)ダイヤモンド放射線検出器の高温動作特性評価
宮崎大二郎, 金子純一, 嶋岡毅紘, 上野克宜, 坪田雅巧, 小泉均, 田所孝, 茶屋原昭義, 梅沢仁, 桑原均, 鹿田真一, 日本原子力学会秋の大会予稿集(CD-ROM), 2013, 2013

オフ角制御高圧高温合成IIa型基板上に合成したCVD単結晶ダイヤモンドの高温環境における電荷キャリア輸送特性評価
宮崎大二郎, 金子純一, 嶋岡毅紘, 上野克宜, 坪田雅功, 小泉均, 田所孝広, 茶屋原昭義, 梅沢仁, 桑原均, 鹿田真一, ダイヤモンドシンポジウム講演要旨集, 27th, 2013

ビームハローモニタへの応用を目指した単結晶CVDダイヤモンドの合成と評価
嶋岡毅紘, 金子純一, 青柳秀樹, 佐竹良太, 宮崎大二郎, 青木毅, 深見健二, 鈴木伸介, 満田史織, 茶谷原昭義, 渡邊幸志, 鹿田真一, ダイヤモンドシンポジウム講演要旨集, 27th, 2013

SiO₂セルフフラックスを用いたGd₂Si₂O₇:Ce焼結体における粒成長と対α線検出器への応用
西方真美, 植田あき, 樋口幹雄, 金子純一, 坪田陽一, 忠永清治, 石橋浩之, 結晶成長国内会議予稿集(CD-ROM), 43rd, 2013

シンチレータを用いた自己遮蔽利用型食品用簡易スクリーニング放射線検出器の検討
鍋田志生, 金子純一, 坪田陽一, 中野隆司, 中野貴寛, 高橋裕之, 田中大之, 日本原子力学会北海道支部研究発表会講演要旨集, 31st, 2013

CVDダイヤモンド中の電荷キャリア輸送特性に対する生成キャリア密度の影響
嶋岡毅紘, 金子純一, 青柳秀樹, 佐竹良太, 宮崎大二郎, 青木毅, 深見健二, 鈴木伸介, 満田史織, 茶谷原昭義, 渡邊幸志, 梅沢仁, 鹿田真一, 日本原子力学会北海道支部研究発表会講演要旨集, 31st, 2013

放射線検出器への応用を目指したCVDダイヤモンド単結晶の合成と評価
金子純一, 日本結晶成長学会バルク成長分科会研究会資料集, 89th, 2013

TSSG法により合成したGPS:Ce単結晶シンチレータの回転数制御によるボイド低減と発光量の改善
坪田陽一, 金子純一, 樋口幹雄, 嶋岡毅紘, 東井宏平, 石橋浩之, 日本原子力学会春の年会予稿集(CD-ROM), 2013, 2013

X線を用いたCeドープGPSシンチレータの耐放射線性に関する研究
皆川萌, 坪田陽一, 金子純一, 小泉均, 樋口幹雄, 東井宏平, 石橋浩之, 日本原子力学会秋の大会予稿集(CD-ROM), 2013, 2013

透光性Gd₂Si₂O₇:Ce多結晶薄板の作製とその対α線シンチレーション特性
西方真美, 植田あき, 樋口幹雄, 金子純一, 坪田陽一, 石橋浩之, 忠永清治, 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 26th, 2013

TSSG法により合成したGd₂Si₂O₇:Ce単結晶シンチレータの高温発光特性評価
坪田陽一, 金子純一, 樋口幹雄, 東井宏平, 皆川萌, 石橋浩之, 日本原子力学会秋の大会予稿集(CD-ROM), 2013, 2013

5cm角GPSシンチレータプレートを用いたα線ダストモニタの開発
東井宏平, 金子純一, 井崎賢二, 嶋岡毅紘, 坪田陽一, 森下祐樹, 樋口幹雄, 日本原子力学会北海道支部研究発表会講演要旨集, 31st, 2013

Top-seeded solution growth of Gd₂Si₂O₇:Ce single crystals and their high temperature scintillation properties
坪田陽一, 金子純一, 樋口幹雄, 東井宏平, 皆川萌, 石橋浩之, Journal of Flux Growth, 8, 2, 2013

食品の自己遮蔽を利用した簡易型スクリーニング放射線検出器の検討
鍋田志生, 金子純一, 坪田陽一, 中野隆司, 中野貴寛, 高橋裕之, 田中大之, 日本食品科学工学会大会講演集, 60th, 2013

Development of Neutron Diagnostic System for LHD Deuterium Experiment　　　　　　　　　　　　　　　
Iguchi, T, Tomita, H, Kawarabayashi, J, Uritani, A, Watanabe, K, Nishio, N, Yamamoto, Y, Sasao, M, Ishii, K, Kaneko, J.H, Takada, E, Yamanishi, H, Murakami, S, Nishitani, T, Ochiai, K, Ishikawa, M, Isobe, M, Osakabe, M, Miyake, H, NIFS Annual Report Apr.2011 - Mar.2012, 2011, 218, Nov. 2012
English

GPSシンチレータプレートのα線ダストモニタ適用試験
嶋岡毅紘, 東井宏平, 金子純一, 井崎賢治, 坪田陽一, 樋口幹雄, 西山修輔, 日本原子力学会秋の大会予稿集(CD-ROM), 2012, ROMBUNNO.I55, 94, 03 Sep. 2012
Pu取扱い施設では一般にα線ダストモニタによって空気汚染の連続監視を行っている。本計測ではPu由来の5.5MeVα線とバックグラウンドであるRn子孫核種由来の7.7MeVを中心とするα線とを弁別する必要があり、Si表面障壁型半導体検出器が一般に使用される。しかし耐久性、耐ノイズ性に問題があるためJAEAの井崎らはZnS:Agシンチレータを代替とするモニタを開発した。本研究ではZnSに代わり、高エネルギー分解能をもつGd2Si2O7:Ce(GPS:Ce)シンチレータを粉砕、ガラス基板上に固定、機械研磨することでエネルギー分解能を維持したまま大面積化する事に成功した。今回、施設で使用されている紙フィルターを使用し、ダストモニタとしての適用試験を行った。その結果、エネルギー弁別性能の指標であるRn子孫核種除去率をZnS:Agシンチレータと比較して20％程度向上できる見込みを得た。, Atomic Energy Society of Japan, Japanese

TSSG法によるGd₂Si₂O₇:Ce単結晶シンチレータの合成と窒素中アニールによる発光量の改善
坪田陽一, 金子純一, 樋口幹雄, 石橋浩之, 西山修輔, 嶋岡毅紘, 応用物理学会学術講演会講演予稿集(CD-ROM), 73rd, ROMBUNNO.12A-C7-8, 27 Aug. 2012
Japanese

人工ダイヤモンド放射線検出器への応用を目指した化学気相合成単結晶ダイヤモンドの合成と評価
金子純一, New Diamond, 28, 1, 2012

オフ角付高圧高温合成IIa基板上へのCVD単結晶ダイヤモンドの合成と電荷キャリア輸送特性の評価 2
佐竹良太, 宮崎大二郎, 金子純一, 藤田文行, 渡邊幸志, 茶谷原昭義, 梅沢仁, 坪内信輝, 鹿田真一, 磯部光孝, 日本原子力学会秋の大会予稿集(CD-ROM), 2012, 2012

オフ角制御高圧高温合成IIa型基板上へのCVD単結晶ダイヤモンドの合成と評価 3~CH₄濃度・RF出力の電荷キャリア輸送特性への影響~
佐竹良太, 金子純一, 宮崎大二郎, 渡邊幸志, 茶谷原昭義, 梅沢仁, 坪内信輝, 鹿田真一, 磯部光孝, ダイヤモンドシンポジウム講演要旨集, 26th, 2012

Ceドープ希土類ピロケイ酸塩単結晶の合成とそのシンチレーション特性
矢尾真人, 樋口幹雄, 坪田陽一, 嶋岡毅紘, 金子純一, 高橋順一, 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 25th, 2012

GPS高エネルギー分解能シンチレータによる高信頼性α線波高弁別検出器の開発
金子純一, 樋口幹雄, 藤田文行, 西山修輔, 坪田陽一, 嶋岡毅紘, 井崎賢二, 日本原子力研究開発機構JAEA-Review(Web), 2012-031, 2012

GPSシンチレータを用いた高エネルギー分解能α線ダストモニタの開発
嶋岡毅紘, 金子純一, 井崎賢治, 坪田陽一, 東井宏平, 樋口幹雄, 西山修輔, 日本原子力学会北海道支部研究発表会講演要旨集, 30th, 2012

TSSG法により合成したGPS:Ce単結晶シンチレータの発光特性濃度依存性
坪田陽一, 金子純一, 樋口幹雄, 嶋岡毅紘, 西山修輔, 藤田文行, 蔵重和久, 石橋浩之, 日本原子力学会秋の大会予稿集(CD-ROM), 2011, ROMBUNNO.J10, 02 Sep. 2011
Japanese

α線ダストモニタ用高エネルギー分解能GPSシンチレータプレートの開発
嶋岡毅紘, 金子純一, 坪田陽一, 井崎賢治, 樋口幹雄, 西山修輔, 藤田文行, 日本原子力学会秋の大会予稿集(CD-ROM), 2011, ROMBUNNO.J11, 02 Sep. 2011
Japanese

核分裂中性子と低エネルギー光子に対するGPSシンチレータの応答特性評価
嶋岡毅紘, 金子純一, 坪田陽一, 樋口幹雄, 西山修輔, 石橋浩之, 藤田文行, 日本原子力学会秋の大会予稿集(CD-ROM), 2011, ROMBUNNO.J09, 02 Sep. 2011
Japanese

大型自立単結晶CVDダイヤモンド板の作製と結晶性,放射線応答
坪内信輝, 杢野由明, 垣本明憲, 山田英明, 茶谷原昭義, 藤田文行, 金子純一, 鹿田真一, 応用物理学関係連合講演会講演予稿集(CD-ROM), 58th, 2011

オフ角制御高圧高温合成IIa基板上へのCVD単結晶ダイヤモンドの合成と電荷収集効率及びμτ積の評価
今野雄太, 佐竹良太, 金子純一, 西紀彦, 後藤拓人, 藤田文行, 渡邊幸志, 茶谷原昭義, 梅澤仁, 坪内信輝, 鹿田真一, 磯部光孝, 日本原子力学会秋の大会予稿集(CD-ROM), 2011, 2011

大型自立単結晶CVDダイヤモンド板の作製とその結晶性及び放射線応答
坪内信輝, 杢野由明, 垣本明憲, 藤田文行, 金子純一, 山田英明, 茶谷原昭義, 鹿田真一, ダイヤモンドシンポジウム講演要旨集, 25th, 2011

高周波加熱炉をもちいた金属溶媒法によるhBN結晶の合成と評価
佐竹良太, 金子純一, 坪田陽一, 谷口尚, 渡邊賢司, 樋口幹雄, 藤田文行, ダイヤモンドシンポジウム講演要旨集, 25th, 2011

オフ角制御高圧高温合成IIa型基板上へのCVD単結晶ダイヤモンドの合成と評価 2~CH₄濃度による特性変化~
金子純一, 佐竹良太, 藤田文行, 今野雄太, 西紀彦, 後藤拓人, 渡辺幸志, 茶谷原昭義, 梅澤仁, 坪内信輝, 鹿田真一, 磯部光孝, ダイヤモンドシンポジウム講演要旨集, 25th, 2011

TSSG法によるGPS:Ceシンチレータ単結晶大型化の試みと発光特性評価
坪田陽一, 金子純一, 樋口幹雄, 石橋浩之, 嶋岡毅紘, 西山修輔, 藤田文行, 蔵重和久, 日本原子力学会北海道支部研究発表会講演要旨集, 29th, 2011

α線ダストモニタ用高エネルギー分解能GPSシンチレータプレートの試作と評価
嶋岡毅紘, 金子純一, 坪田陽一, 井崎賢治, 樋口幹雄, 西山俊輔, 藤田文行, 日本原子力学会北海道支部研究発表会講演要旨集, 29th, 2011

2050年のダイヤモンド将来展望-パワーデバイス・原子力応用・量子などを中心に-
小泉聡, 寺地徳之, 梅沢仁, 牧野俊晴, 金子純一, 小出康夫, 水落憲和, 水落憲和, 渡邊幸志, 渡邊賢司, 谷口尚, 野瀬健二, New Diamond, 27, 1, 2011

TSSG法によるGPS:Ce単結晶シンチレータの合成と組成的過冷却の抑制
坪田陽一, 川村宗範, 金子純一, 樋口幹雄, 西山修輔, 藤田文行, 蔵重和久, 石橋浩之, 応用物理学関係連合講演会講演予稿集(CD-ROM), 58th, 2011

Ceドープ希土類ピロケイ酸塩の相関係とその発光特性
矢尾真人, 樋口幹雄, 金子純一, 高橋順一, 日本セラミックス協会秋季シンポジウム講演予稿集, 24th, 2011

Gd₂Si₂O₇:Ce(GPS)単結晶シンチレータの開発
金子純一, 日本セラミックス協会秋季シンポジウム講演予稿集, 24th, 2011

固相法によるCeドープ希土類ピロケイ酸塩の合成とその蛍光特性
矢尾真人, 樋口幹雄, 高橋順一, 金子純一, 日本化学会北海道支部夏季研究発表会講演要旨集, 2011, 2011

GPS高エネルギー分割能シンチレータによる高信頼性α線波高弁別検出器の開発
金子純一, 樋口幹雄, 藤田文行, 西山修輔, 坪田陽一, 井崎賢二, 日本原子力研究開発機構JAEA-Review(Web), 2011-030, 2011

Dependence of Scintillation Properties on Cerium Concentration for GPS Single Crystal Scintillators Grown by a TSSG Method
Youichi Tsubota, Junichi H. Kaneko, Mikio Higuchi, Takehiro Shimaoka, Shusuke Nishiyama, Hiroyuki Ishibashi, Fumiyuki Fujita, 2011 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (NSS/MIC), 1923, 1926, 2011
Single crystal Gd2Si2O7:Ce (GPS:Ce) scintillators were grown by a top seeded solution growth (TSSG) method and their crystal structures and scintillation properties were measured. Single crystal GPS with several cerium concentration; (Gd1-xCex)(2)Si2O7 (x=0.025, 0.1, 0.15), were synthesized with a RF-Czochralski furnace. For GPS: Ce 2.5 at.%, a crystal structure was orthorhombic. For GPS: Ce 10 and 15 at.%, these were triclinic. In PL measurements, broad emissions around 350 to 450 nm correspond to 5d-4f transitions of Ce3+ were observed. In gamma-ray measurements, each scintillator shows light output larger than that of BGO. High energy resolution of around 5% was obtained for GPS: Ce 2.5 and 10 at.%. GPS: Ce 2.5 at.% shows ca. 4.4 times light output larger than that of BGO. Decay times of triclinic GPS were faster than that of orthorhombic GPS., IEEE, English

ダイヤモンド・ショットキーダイオードの耐放射線性
鈴木真理子, 酒井忠司, 金子純一, 応用物理学関係連合講演会講演予稿集(CD-ROM), 57th, 2010

積極的電荷捕獲と光I-V測定を用いたCVD合成ダイヤモンド中における電荷キャリア捕獲準位の評価
後藤拓人, 藤田文行, 金子純一, 佐藤圭, 坪内信輝, 杢野由明, 茶谷原昭義, 垣本明徳, 本間彰, 鹿田真一, 古坂道弘, 日本原子力学会秋の大会予稿集(CD-ROM), 2010, 2010

合成条件と使用基板がホモエピタキシャルCVD単結晶ダイヤモンドの電荷キャリア輸送特性に与える影響
垣本明徳, 今野雄太, 金子純一, 藤田文行, 後藤拓人, 坪内信輝, 杢野由明, 茶谷原昭義, 渡邊幸志, 梅澤仁, 鹿田真一, 日本原子力学会秋の大会予稿集(CD-ROM), 2010, 2010

ダイヤモンドショットキーm-i-p⁺ダイオードの高ドーズ量γ線に対する安定性
鈴木真理子, 酒井忠司, 金子純一, ダイヤモンドシンポジウム講演要旨集, 24th, 2010

積極的電荷捕獲と光漏れ電流測定を用いたCVDダイヤモンド中における電荷キャリア捕獲準位の評価
後藤拓人, 藤田文行, 金子純一, 今野雄太, 佐藤圭, 坪内信輝, 杢野由明, 茶谷原昭義, 垣本明徳, 本間彰, 鹿田真一, 古坂道弘, ダイヤモンドシンポジウム講演要旨集, 24th, 2010

オフ角制御IIa型ダイヤモンド基板を使用したCVD単結晶ダイヤモンド自立膜の合成と評価
今野雄太, 後藤拓人, 金子純一, 藤田文行, 西紀彦, 梅澤仁, 渡邊幸志, 茶谷原昭義, 坪内信輝, 鹿田真一, ダイヤモンドシンポジウム講演要旨集, 24th, 2010

合成条件と使用基板がホモエピタキシャルダイヤモンドの電荷キャリア輸送特性に与える影響
垣本明徳, 今野雄太, 金子純一, 藤田文行, 後藤拓人, 坪内信輝, 杢野由明, 茶谷原昭義, 渡邊幸志, 鹿田真一, ダイヤモンドシンポジウム講演要旨集, 24th, 2010

オフ角制御IIa型ダイヤモンド基板を使用したCVD単結晶ダイヤモンド自立膜の合成と評価
今野雄太, 後藤拓人, 金子純一, 藤田文行, 西紀彦, 梅澤仁, 渡邊幸志, 茶谷原昭義, 坪内信輝, 鹿田真一, 日本原子力学会北海道支部研究発表会講演要旨集, 28th, 2010

GPS:Ceシンチレータをもちいたα線計測の試み
近藤香織, 坪田陽一, 金子純一, 井崎賢二, 樋口幹雄, 藤田文行, 西山修輔, 日本原子力学会秋の大会予稿集(CD-ROM), 2010, 2010

RE₂Si₂O₇の包晶組成とCe:GPS単結晶育成への応用
樋口幹雄, 佐藤力, 高橋順一, 川村宗範, 金子純一, 応用物理学関係連合講演会講演予稿集(CD-ROM), 57th, 2010

TSSG法によるGd₂Si₂O₇:Ce単結晶シンチレータの合成と発光特性評価
坪田陽一, 川村宗範, 金子純一, 樋口幹雄, 西山修輔, 藤田文行, 蔵重和久, 石橋浩之, 日本原子力学会秋の大会予稿集(CD-ROM), 2010, 2010

TSSG法によるGd₂Si₂O₇:Ce単結晶シンチレータの合成と組成的過冷却の抑制
坪田陽一, 川村宗範, 金子純一, 樋口幹雄, 西山修輔, 藤田文行, 蔵重和久, 石橋浩之, 日本原子力学会北海道支部研究発表会講演要旨集, 28th, 2010

GPS高エネルギー分解能シンチレータによる高信頼性α線波高弁別検出器の開発
金子純一, 樋口幹雄, 藤田文行, 西山修輔, 坪田陽一, 井崎賢二, 日本原子力研究開発機構JAEA-Review(Web), 2010-035, 2010

核融合プラズマ診断用人工ダイヤモンド放射線検出器の中性子応答関数測定
金子純一, 佐藤聡, 藤田文行, 鹿田真一, 日本原子力研究開発機構JAEA-Review(Web), 2010-042, 2010

定位放射線治療のための消滅γ線計測に基づく腫瘍位置同定装置の概念設計
原裕, 島崎紘亘, 金子純一, 高田英治, 藤田文行, 久保直樹, 石川正純, 古坂道弘, 白土博樹, 医学物理 Supplement, 29, 2, 190-191, Apr. 2009
Japanese

人工ダイヤモンドで放射線をはかる 核融合炉用先進放射線検出器の開発
金子純一, 磯部光孝, プラズマ・核融合学会誌, 85, 2, 2009

大型CVD単結晶ダイヤモンド自立膜に対する電荷輸送特性評価
垣本明徳, 藤田文行, 金子純一, 佐藤圭, 今野雄太, 坪内信輝, 杢野由明, 茶谷原昭義, 鹿田真一, 本間彰, 古坂道弘, 日本原子力学会春の年会予稿集(CD-ROM), 2009, 2009

高速合成CVD単結晶ダイヤモンドによる14MeV中性子応答関数測定
佐藤圭, 垣本明徳, 金子純一, 藤田文行, 坪内信輝, 杢野由明, 茶谷原昭義, 佐藤聡, 今野雄太, 本間彰, 鹿田真一, 古坂道弘, 日本原子力学会秋の大会予稿集(CD-ROM), 2009, 2009

希土類ピロケイ酸塩の溶融凝固挙動
佐藤力, 樋口幹雄, 高橋順一, 川村宗範, 金子純一, 日本セラミックス協会秋季シンポジウム講演予稿集, 22nd, 2009

リフトオフ法を用いてCVD合成された大面積単結晶ダイヤモンド自立膜における電荷輸送特性の測定
藤田文行, 垣本明徳, 金子純一, 坪内信輝, 杢野由明, 茶谷原昭義, 佐藤圭, 今野雄太, 本間彰, 鹿田真一, 古坂道弘, ダイヤモンドシンポジウム講演要旨集, 23rd, 2009

PETのための非侵襲動脈血中放射能濃度測定の技術的成立性検証
中丸洋, 久保直樹, 金子純一, 加藤千恵次, 藤田文行, 玉木長良, 本間彰, 古坂道弘, 医学物理 Supplement, 29, 3, 2009

浮遊帯域徐冷法による希土類ピロケイ酸塩の溶融凝固挙動の調査
佐藤力, 樋口幹雄, 高橋順一, 川村宗範, 金子純一, 日本化学会北海道支部夏季研究発表会講演要旨集, 2009, 2009

プラズマエッチングによるダイヤモンド基板表面処理のホモエピタキシャル成長に対する影響
今野雄太, 金子純一, 藤田文行, 渡邊幸志, 原賢二, 佐藤圭, 垣本明徳, 鹿田真一, 本間彰, 古坂道弘, 日本原子力学会北海道支部研究発表会講演要旨集, 27th, 2009

TSSG法によるCe:GPS単結晶育成とそのシンチレーション特性
川村宗範, 樋口幹雄, 金子純一, 西山修輔, 藤田文行, 本間彰, 坪田陽一, 上田俊輔, 蔵重和央, 石橋浩之, 古坂道弘, 応用物理学関係連合講演会講演予稿集, 56th, 1, 2009

Investigation on the Melting-Solidification Behaviors of Rare-Earth Pyrosilicates and Application to the Single Crystal Growth of Ce:Gd₂Si₂O₇
佐藤力, 樋口幹雄, 高橋順一, 川村宗範, 金子純一, Journal of Flux Growth, 4, 2, 2009

PrドープGd₂Si₂O₇の発光特性,および結晶構造
坪田陽一, 金子純一, 樋口幹雄, 川村宗範, 西山修輔, 藤田文行, 本間彰, 古坂道弘, 上田俊輔, 蔵重和久, 石橋浩之, 日本原子力学会北海道支部研究発表会講演要旨集, 27th, 2009

Feasibility Study on an Annihilation Gamma-rays Detection System for a Real-time Tumor-tracking Radiotherapy by Simulation
HARA Y, KANEKO J. H, TAKADA E, FUJITA F, KUBO N, ISHIKAWA M, FURUSAKA M, SHIRATO H, 医学物理 : 日本医学物理学会機関誌 = Japanese journal of medical physics : an official journal of Japan Society of Medical Physics, 28, 0, 283, 284, 01 Apr. 2008
Japanese

放射線検出器用CVD単結晶ダイヤモンド合成に向けた合成条件の検討
佐藤圭, 垣本明徳, 金子純一, 藤田文行, 目黒貴一, 泉健二, 山本喜之, 今井貴浩, 茶谷原昭義, 杢野由明, 渡邊幸志, 鹿田真一, 藤森直治, 古坂道弘, 日本原子力学会秋の大会予稿集(CD-ROM), 2008, 2008

Gd系厚膜シンチレータの開発(5)-中性子イメージングの試み-
春名潤, 金子純一, 佐藤節夫, 川村宗範, 樋口幹雄, 佐伯掌平, 上田俊輔, 蔵重和央, 石橋浩之, 西山修輔, 藤田文行, 本間彰, 古坂道弘, 鬼柳善明, 日本原子力学会秋の大会予稿集(CD-ROM), 2008, 2008

Role of Visualization of Nuclear Radiation in Public Education on Atomic Energy-Visualization of Natural Nuclear Radiation Using a Cloud Chamber-
金子純一, 藤田文行, 奈良林直, 可視化情報学会誌, 28, Suppl.2, 2008

原子力を通した環境・エネルギー問題への寄与-耐放射線・耐環境デバイスとしてのダイヤモンド-
金子純一, New Diamond, 24, 4, 2008

コンプレックスプラズマの新しい秩序の形成過程
藤田文行, 古坂道弘, 金子純一, 西山修輔, プラズマ・核融合学会年会(Web), 25th, 2008

Ce:Gd2Si2O7（Ce2.5-30mol%）単結晶のシンチレーション特性　　　　　　　　　　　　　　　
川村宗範, 金子純一, 樋口幹雄, 西山修輔, 藤田文行, 本間彰, 春名潤, 佐伯掌平, 古坂道弘, 上田俊輔, 蔵重和央, 石橋浩之, 放射線, 34, 3, 188, 192, 2008

動体追跡照射治療への応用を目指したFDG計測システムの最適化設計
原裕, 金子純一, 高田英治, 藤田文行, 久保直樹, 石川正純, 古坂道弘, 白土博樹, 日本原子力学会北海道支部研究発表会講演要旨集, 26th, 4-5, 2008
Japanese

核融合中性子に対する各種放射線検出器の特性評価研究
金子純一, 落合謙太郎, 越智敦彦, 田中秀治, 藤田文行, 日本原子力研究開発機構JAEA-Review, 2007

プラズマ燃焼実験のための先進計測 2.核反応計測 2.5 素子開発
金子純一, 柏木利介, 日比野欣也, 奥野祥二, 飯田敏行, 加藤裕史, 佐藤文信, プラズマ・核融合学会誌, 83, 12, 2007

Gd系厚膜シンチレータの開発(4)-中性子計測の試み-
春名潤, 金子純一, 樋口幹雄, 川村宗範, 佐伯掌平, 八木康洋, 石橋浩之, 藤田文行, 本間彰, 古坂道弘, 鬼柳善明, 日本原子力学会秋の大会予稿集(CD-ROM), 2007, 2007

Gd₂O₃-SiO₂系相図におけるGd₂Si₂O₇周辺の検証
川村宗範, 金子純一, 樋口幹雄, 西山修輔, 藤田文行, 本間彰, 春名潤, 佐伯掌平, 蔵重和央, 石橋浩之, 古坂道弘, 応用物理学関係連合講演会講演予稿集, 54th, 1, 2007

CVDダイヤモンドを用いた放射線検出器の開発 II
中平聡志, 安藤豊, 斎藤裕子, 澤邊厚仁, 山岡和貴, 吉田篤正, 金子純一, 日本物理学会講演概要集, 62, 2, 2007

Gd₂Si₂O₇中のCe濃度と発光特性の相関
佐伯掌平, 春名潤, 金子純一, 樋口幹雄, 川村宗範, 上田俊輔, 蔵重和央, 石橋浩之, 藤田文行, 本間彰, 古坂道弘, 応用物理学会学術講演会講演予稿集, 68th, 1, 2007

CeドープGd₂Si₂O₇単結晶のCe濃度とシンチレーション特性の相関
川村宗範, 川村宗範, 金子純一, 樋口幹雄, 西山修輔, 藤田文行, 本間彰, 春名潤, 佐伯掌平, 上田俊輔, 蔵重和央, 石橋浩之, 古坂道弘, 応用物理学会学術講演会講演予稿集, 68th, 1, 2007

CeドープGd₂Si₂O₇単結晶育成とシンチレーション特性
川村宗範, 金子純一, 樋口幹雄, 山口達, 春名潤, 八木康洋, 須佐憲三, 藤田文行, 本間彰, 西山修輔, 蔵重和央, 石橋浩之, 古坂道弘, UTNL-R(東京大学大学院工学系研究科原子力専攻), 0457, 2007

Response function measurement of Gd2Si2O7 scintillator for neutrons
Jun Haruna, Junichi H. Kaneko, Mikio Higuchi, Sohan Kawamura, Syouhei Saeki, Yasuhiro Yagi, Hiroyuki Ishibashi, Fumiyuki Fujita, Akira Homma, Michihiro Furusaka, Yoshiaki Kiyanagi, 2007 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-11, 1421, +, 2007
Response function measurement of Gd2Si2O7 (GPS) scintillator for thermal neutrons was carried out. GPS single crystals exhibits light output twice higher than GSO single crystals for thermal neutrons. In addition, similar experiments with GPS scintillators of 50 pm in thickness were conducted to improve signal-to-noise ratio between neutrons and gamma-ray. GPS powder samples, size of each particle was 50 pro, showed lower light output than that of GPS single crystals, because absorption and scattering of scintillation light at the sample surface reduced the correction efficiency of scintillation fight. Optimization of the particle size, reflectors and techniques to fix the GPS sample will improve the powder density and detection efficiency because powder samples were directly coated on a glass plate in this experiment., IEEE, English

Dependence of crystal structure and luminescence property of Gd2Si2O7 on cerium concentration
Syohei Saeki, Junichi H. Kaneko, Mikio Higuchi, Sohan Kawamura, Jun Haruna, Fumiyuki Fujita, Akira Homma, Shusuke Nishiyama, Shusuke Ueda, Kazuhisa Kurashige, Hiroyuki Ishibashi, Michihiro Furusaka, 2007 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-11, 1426, +, 2007
Dependence of crystal structure and luminescence property of Gd2Si2O7 (Ce:GPS) was investigated using polycrystalline samples synthesized by a solid state reaction method. Three types of crystal structures and different luminescence spectra were observed according to concentration of cerium. The largest luminescence intensity was observed for orthorhombic structure whose cerium concentration was between 0.75 and 2.5 mol%., IEEE, English

Scintillation characteristics of (Gd1-xCex)(2)Si2O7 (x=0.025-0.25) single crystals fabricated by floating zone method
S. Kawamura, J. H. Kaneko, M. Higuchi, J. Haruna, S. Saeki, F. Fujita, A. Homma, S. Nishiyama, S. Ueda, K. Kurashige, H. Ishibashi, M. Furusaka, 2007 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-11, 56, 1, 1365, +, 2007
Cerium-doped gadolinium pyrosilicate single crystals Ce : Gd2Si2O7 with various Cc concentrations of 2.5-25 mol% were fabricated using floating zone method. Their scintillation performances were investigated under irradiation of gamma rays of Cs-137. The Ce concentration dependence of scintillation characteristics and high-performance scintillation characteristics were obtained: 35 times greater light output than BGO single crystals, rapid decay, and good energy resolutions of 5.1-8.4%. Xray diffraction patterns of Ce : Gd2Si2O7 also showed Ce concentration dependence of the crystal structure of Ce Gd2Si2O7., IEEE, English

Gd系薄膜シンチレータの開発(2)~焼結による薄膜化~
土田昇平, 春名潤, 金子純一, 山口達, 須佐憲三, 三浦誠司, 奥隆之, 藤田文行, 本間彰, 沢村晃子, 古坂道弘, 清水裕彦, 鬼柳善明, 日本原子力学会春の年会要旨集(CD-ROM), 2006, 2006

Gd系薄膜シンチレータの開発(3)~Gdパイロシリケイト粉体シンチレータの合成と評価~
山口達, 春名潤, 金子純一, 須佐憲三, 三浦誠司, 八木康洋, 川村宗範, 奥隆之, 藤田文行, 本間彰, 石橋浩之, 沢村晃子, 古坂道弘, 清水裕彦, 鬼柳善明, 日本原子力学会春の年会要旨集(CD-ROM), 2006, 2006

ダイヤモンド電子源のX線源への適用-評価装置作製とX線発生実験-
福本栄, 本間彰, 金子純一, 西林良樹, 植田暁彦, 山本喜之, 今井貴浩, 藤田文行, 古坂道弘, ダイヤモンドシンポジウム講演要旨集, 20th, 2006

FZ法によるCeドープGdパイロシリケイト単結晶育成とシンチレーション特性評価
川村宗範, 金子純一, 樋口幹雄, 山口達, 春名潤, 八木康洋, 須佐憲三, 藤田文行, 本間彰, 西山修輔, 蔵重和央, 石橋浩之, 古坂道弘, 日本原子力学会秋の大会予稿集(CD-ROM), 2006, 2006

UVパルスレーザーを用いた真性ダイヤモンド薄膜中における輸送特性評価手法の開発(2)-局所励起を用いた飛行時間測定と出力信号のシミュレーション-
押木祐介, 金子純一, 藤田文行, 本間彰, 川村宗範, 古坂道弘, 渡辺幸志, 目黒貴一, 山本喜之, 今井貴浩, ダイヤモンドシンポジウム講演要旨集, 20th, 2006

中性子光学素子への応用を目指したPMN-PT単結晶の回折角変化測定
川村宗範, 田辺和明, 金子純一, 大竹淑恵, 相沢一也, 藤本弘之, 藤田文行, 本間彰, 古坂道弘, 日本原子力学会春の年会要旨集(CD-ROM), 2006, 2006

Gd系中性子シンチレータの開発
春名潤, 八木康洋, 川村宗範, 金子純一, 樋口幹雄, 西山修輔, 蔵重和央, 上田俊輔, 石橋浩之, 藤田文行, 本間彰, 古坂道弘, 鬼柳善明, 日本中性子科学会年会講演概要集, 6th, 2006

Floating zone growth and scintillation characteristics of cerium-doped gadolinium pyrosilicate single crystals
S. Kawamura, J. H. Kaneko, M. Higuchi, T. Yamaguchi, J. Haruna, Y. Yagi, K. Susa, F. Fujita, A. Homma, S. Nishiyama, H. Ishibashi, K. Kurashige, M. Furusaka, 2006 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOL 1-6, 1160, 1163, 2006
Growth of cerium-doped gadolinium pyrosilicate (Gd2Si2O7:Ce) single crystals, which show 2.5 times greater light output for gamma-rays and five times greater light output for alpha particles than GSO single crystals, is accomplished using Floating Zone growth method (FZ method). Although growth of Gd2Si2O7 (GPS) single crystal is considered to be difficult because it melts incongruently according to the phase diagram in a Gd2O3-SiO2 system, we attempted crystal growth of Ce:GPS because the possibility exists that heavy Ce doping changes the phase diagram. Transparent single crystals were obtained, but cracks were observed in the crystals. The crystal structure was triclinic with space group P-/1 and density of 5.5 g/cm(3). Two peaks were observed by photoluminescence spectrum measurement at 374 nm and 394 nm caused by 5d-4f transition in Ce3+ ion. Decay times of Ce:GPS were 46 ns for gamma-ray and 39 ns for alpha particles; its density was 5.5 g/cm(3). We consider that the energy resolution of 23% will be improved by fabrication of large crystals and improvement of crystal perfectibility., IEEE, English

01pC34P Dust Particles in Positive Column Plasmas of a DC Glow Discharge(III)
OINUMA Gaku, FUJITA Fumiyuki, KANEKO Junichi, FURUSAKA Michihiro, プラズマ・核融合学会年会予稿集, 22, 220, 220, 2005
プラズマ・核融合学会, Japanese

高配向ダイヤモンド膜を用いた高分解能紫外線位置センサの開発
辻勝英, 林和志, 金子純一, 藤田文行, 本間彰, 押木祐介, 沢村輝子, 古坂道弘, ダイヤモンドシンポジウム講演要旨集, 19th, 2005

絶縁性ダイヤモンド薄膜中における電荷キャリア輸送特性評価手法の開発
押木祐介, 辻勝英, 金子純一, 藤田文行, 本間彰, 寺地徳之, 古坂道弘, ダイヤモンドシンポジウム講演要旨集, 19th, 2005

多結晶体高配向ダイヤモンド膜を用いた紫外線位置センサー
辻勝英, 押木祐介, 林和志, 金子純一, 藤田文行, 本間彰, 沢村晃子, 応用物理学関係連合講演会講演予稿集, 52nd, 2, 2005

YBO₃中性子シンチレータのホウ素中性子捕捉療法用リアルタイム中性子モニターへの応用
山口達, 白石和正, 金子純一, 片桐政樹, 石川正純, 沢村晃子, 日本原子力学会春の年会要旨集, 43rd, 2005

シンチレーション検出器(原標題は英語)
広田克也, 清水裕彦, BERTAINA Mario, 滝沢慶之, 酒井健二, 金子純一, 石井満, KEK Proceedings, 2004-17, 2005

Application of an ultra-miniature thermal neutron monitor for BNCT irradiation field study
Masayori Ishikawa, Hiroaki Kumada, Kazuyoshi Yamamoto, Junichi H. Kaneko, Hiroyuki Takahashi, 2005 IEEE NUCLEAR SCIENCE SYMPOSIUM CONFERENCE RECORD, VOLS 1-5, 2917, 2919, 2005
Recently, a new type of detector using a scintillator coupled with an optical fiber was developed for the same purpose. Among these types of detectors, the SOF (Scintillator with Optical Fiber) detector has been used for monitoring thermal neutron during boron neutron capture therapy in Japan. The detector probe of the SOF detector system is smaller than other neutron monitors such as gas counters which makes the SOF detector more useful for thermal neutron monitoring in restricted spaces. A phantom experiment was performed using the SOF detector to test the applicability for a boron neutron capture therapy irradiation field study. The result measured by the SOF detector agrees well with a gold wire measurement in spite of only a 30-minutes measurement time with the SOF detector., IEEE, English

Application of an ultra-miniature thermal neutron monitor for BNCT irradiation field study
Ishikawa Masayori, Kumada Hiroaki, Yamamoto Kazuyoshi, Kaneko Junichi H, Takahashi Hiroyuki, 2005 IEEE Nuclear Science Symposium Conference Record, Vols 1-5, 5, 2917, 2919, 2005, [Peer-reviewed]

放射線計測技術に基づくダイヤモンド結晶中の電荷キャリア輸送特性評価とそれに基づく多結晶ダイヤモンドの電気特性改善
辻勝英, 白石和正, 金子純一, 林和志, 橘武史, 藤田文行, 本間彰, 沢村晃子, ダイヤモンドシンポジウム講演要旨集, 18th, 2004

Evaluation on the electric charge carrier transport characteristics in artificial diamond based on radiation measurement technology.
金子純一, New Diamond, 20, 3, 2004

圧電性単結晶をもちいた能動的X線光学素子の基礎研究
金子純一, 川村宗範, 藤本弘之, 水野忠彦, 高間俊彦, 大竹淑恵, 藤田文行, 本間彰, 古坂道弘, 日本原子力研究所JAERI-Conf, 2004

UVパルスレーザーを用いたダイヤモンド中の電荷キャリア輸送特性評価手法の開発
押木祐介, 辻勝英, 本間彰, 藤田文行, 金子純一, 沢村晃子, ダイヤモンドシンポジウム講演要旨集, 18th, 2004

圧電性単結晶を用いた能動的中性子・X線光学素子の開発
川村宗範, 金子純一, 大竹淑恵, 藤本弘之, 藤田文行, 沢村晃子, 古坂道弘, 日本原子力学会春の年会要旨集, 42nd, 2004

YBO₃中性子シンチレータのホウ素中性子捕捉療法用リアルタイム中性子モニターへの応用
金子純一, 石川正純, 片桐政樹, 落合謙太郎, 白石和正, 土田昇平, 沢村晃子, 西谷健夫, 日本原子力学会春の年会要旨集, 42nd, 2004

GSO中性子シンチレータの合成と評価
山口達, 金子純一, 三浦誠司, 須佐憲三, 奥隆之, 藤田文行, 本間彰, 古坂道弘, 清水裕彦, 日本中性子科学会年会講演概要集, 4th, 2004

圧電性単結晶を用いた能動的中性子・X線光学素子の開発
川村宗範, 金子純一, 大竹淑恵, 藤本弘之, 藤田文行, 沢村晃子, 古坂道弘, 日本中性子科学会年会講演概要集, 4th, 2004

GSO中性子シンチレータ薄膜化の試み
土田昇平, 山口達, 金子純一, 須佐憲三, 三浦誠司, 奥隆之, 藤田文行, 古坂道弘, 清水裕彦, 日本中性子科学会年会講演概要集, 4th, 2004

単結晶CVDダイヤモンドを用いた放射線検出器の作製 I
吉崎聡, 平井佑樹, 寺地徳之, 金子純一, 沢村晃子, 伊藤利道, 応用物理学関係連合講演会講演予稿集, 50th, 2, 2003

積層型CVD単結晶ダイヤモンド放射線検出器の試作と特性評価
平井佑樹, 吉崎聡, 白石和正, 金子純一, 寺地徳之, 沢村晃子, 伊藤利道, ダイヤモンドシンポジウム講演要旨集, 17th, 2003

立方晶窒化ホウ素による放射線計測の試み
平井佑樹, 白石和正, 金子純一, 谷口尚, 沢村晃子, 日本原子力学会秋の大会予稿集, 2003, 2003

人工ダイヤモンド放射線検出器の開発(17)-積層型CVD単結晶ダイヤモンドを用いた14MeV中性子応答関数測定実験-
平井佑樹, 白石和正, 吉崎聡, 金子純一, 寺地徳之, 西谷健夫, 沢村晃子, 伊藤利道, 日本原子力学会秋の大会予稿集, 2003, 2003

人工ダイヤモンド放射線検出器の開発 (16) CVD単結晶ダイヤモンド薄膜の利用
平井佑樹, 吉崎聡, 白石和正, 金子純一, 寺地徳之, 沢村晃子, 伊藤利道, 日本原子力学会春の年会要旨集, 41st, 2003

中性子用GSOシンチレータの開発 (1) 機械研磨による薄膜化
渡辺正智, 平井佑樹, 金子純一, 鬼柳善明, 沢村晃子, 猪野隆, 古坂道弘, 奥隆之, 清水裕彦, 日本原子力学会春の年会要旨集, 41st, 2003

過熱液滴型中性子線量計の高エネルギー中性子に対する応答 【II】
阿部正史, MALA D, 金子純一, 沢村晃子, 津田修一, 西谷健夫, 応用物理学関係連合講演会講演予稿集, 50th, 1, 2003

D-T中性子源FNSにおける中性子スカイシャイン実験
脇坂雅志, 金子純一, 沢村晃子, 落合謙太郎, 西谷健夫, 吉田茂生, 日本原子力学会秋の大会予稿集, 2003, 2003

Development of Monitors and Dosimeters for High-Energy Radiation
小田啓二, 沢村晃子, 金子純一, 中根佳弘, 山口恭弘, 放射線高度利用研究第四期研究成果報告書 大学・原研プロジェクト共同研究 平成15年, 2003

Deposition of high quality diamond films for UV/radiation detectors　　　　　　　　　　　　　　　
Proceedings of the 10th International symposium on advanced materials, ISAM 2003, 65, 66, 2003

Evaluation of Neutrons Leaking from the Accelerator Facilities　　　　　　　　　　　　　　　
9th Conf. Neutron Dosimetry Dosimeter, 0, 2003

Superheated Emulsion --- As High Energy Neutron　　　　　　　　　　　　　　　
The 9th Conf. Neutron Dosimetry Dosimeter, 126, 2003

D-T Neutron Skyshine Experiments at JAERI/FNS
NISHITANI Takeo, OCHIAI Kentaro, YOSHIDA Shigeo, TANAKA Ryohei, WAKISAKA Masashi, NAKAO Makoto, SATO Satoshi, YAMAUCHI Michinori, HORI Jun-ichi, TAKAHASHI Akito, KANEKO Jun-ichi, SAWAMURA Teruko, Kakuyūgō kenkyū, 79, 3, 282, 289, 2003
The D-T neutron skyshine experiments have been carried out at the Fusion Neutronics Source (FNS) of JAERI with the neutron yield of ∼1.7×10¹¹n/s. The concrete thickness of the roof and the wall of a FNS target room are 1.15 and 2 m, respectively. The FNS skyshine port with a size of 0.9 × 0.9 m² was open during the experimental period.The radiation dose rate outside the target room was measured as far as about 550 m away from the D-T target point with a spherical rem-counter. The highest neutron dose was about 0.5 μSv/hr at a distance of 30 m from the D-T target point and the dose rate was attenuated to 0.002 μSv/hr at a distance of 550 m. The measured neutron dose distribution was analyzed with Monte Carlo code MCNP-4B and a simple line source model. The MCNP calculation overestimates the neutron dose in the distance range larger than 250 m. The neutron spectra were evaluated with a ³He detector with different thickness of polyethylene neutron moderators. Secondary gamma-rays were measured with high purity Ge detectors and NaI scintillation detectors., The Japan Society of Plasma Science and Nuclear Fusion Research, Japanese

Investigation on charge trapping mechanism in a high-purity HP/HT type IIa diamond single crystal using nuclear methods　　　　　　　　　　　　　　　
Proceedings of the 10th International symposium on advanced materials, ISAM 2003, 7, 8, 2003

Fusion power measurement based on $^{16}$O(n,p)$^{16}$N reaction in flowing water
Nishitani, Takeo, Uno, Yoshitomo, Kaneko, Junichi, Ochiai, Kentaro, Maekawa, Fujio, Journal of Nuclear Science and Technology, 39, Suppl.2, 1139, 1142, Aug. 2002, [Peer-reviewed]
FNSで行った実験結果に基づき、流水の放射化を利用したITER用中性子モニターの設計を行った。水配管は径20mmとし、照射端は赤道面のフィラーブランケットモジュール内に真空容器を貫通して挿入する構造とした。$gamma$線測定ステーションは生体遮蔽外のピットに設置し、照射端からの距離は20mとした。この配置に基づき、各種特性をMCNP-4bコードを用いて評価を行った。時間分解能は水配管に沿った放射化反応の分布及び乱流拡散を考慮して、10m/sの流速に対し時間分解能100ms( ITER要求値)以下となった。また放射化量はプラズマの位置にほとんど依存しないことがわかった。$gamma$線測定ステーションにおいて異なる検出効率の$gamma$線検出器を2台用いることによって、100kW-500MWのITERの出力範囲で測定が可能であることを示した。, English

過熱液滴型中性子線量計の高エネルギー中性子に対する応答
阿部正史, 金子純一, 村井郁夫, 沢村晃子, 津田修一, 応用物理学会学術講演会講演予稿集, 63rd, 1, 2002

D-T中性子源FNSにおけるスカイシャイン実験 (1) 実験概要および線量率評価
落合謙太郎, 西谷健夫, 中尾誠, 吉田茂生, 田中良平, 高橋亮人, 金子純一, 脇坂雅志, 沢村晃子, 日本原子力学会秋の大会予稿集, 2002, 2002

D-T中性子源FNSにおけるスカイシャイン実験 (2) スカイシャイン中性子測定
脇坂雅志, 金子純一, 沢村晃子, 落合謙太郎, 西谷健夫, 吉田茂生, 日本原子力学会秋の大会予稿集, 2002, 2002

人工ダイヤモンド放射線検出器の開発 (15) 高圧高温合成IIa型ダイヤモンド中の捕獲準位のイオン化率の計算
田中照也, 平井佑樹, 金子純一, 沢村晃子, 片桐政樹, 西谷健夫, 飯田敏行, 日本原子力学会春の年会要旨集, 40th, 2002

パルス中性子イメージング検出法の開発 (12) Li₂B₄O₇単結晶による中性子検出
片桐政樹, 坂佐井馨, 松林政仁, 藤健太郎, 金子純一, 高橋浩之, 中沢正治, 日本原子力学会春の年会要旨集, 40th, 2002

過熱液滴型中性子線量計の高エネルギー領域における応答 II
阿部正史, 田村昌也, 山田琢馬, 平井佑樹, 金子純一, 村井郁夫, 本間彰, 藤田文行, 津田修一, 日本原子力学会春の年会要旨集, 40th, 2002

高圧高温合成IIa型ダイヤモンドにおける電荷捕獲機構の推定
平井佑樹, 田中照也, 金子純一, 沢村晃子, 片桐政樹, 西谷健夫, 飯田敏行, ダイヤモンドシンポジウム講演要旨集, 16th, 2002

マイクロストリップガスチェンバーによる二次元中性子検出器の開発 (1) Gdコンバータによる転換電子検出実験
中村龍也, 正岡聖, 山岸秀志, 曽山和彦, 金子純一, 日本原子力学会春の年会要旨集, 40th, 2002

マイクロストリップガスチェンバーによる二次元中性子検出器の開発 (2) Gdコンバータ検出器設計の最適化計算
正岡聖, 中村龍也, 山岸秀志, 曽山和彦, 金子純一, 日本原子力学会春の年会要旨集, 40th, 2002

Neutrons Leaked from a 45 MeV Linac Facility　　　　　　　　　　　　　　　
Proceedings of the 1st Asian Oceanic Congress for Radiation Protection (AOCRP-1), 0, 2002

Present status and problems of synthetic diamond radiation detectors
KANEKO Junichi H., Ionizing radiation., 27, 2, 49, 62, 01 Apr. 2001
応用物理学会,放射線分科会, Japanese

Technical feasibility study for the D-T neutron monitor using activation of flowing water
Uno, Yoshitomo, Kaneko, Junichi, Nishitani, Takeo, Maekawa, Fujio, Tanaka, Teruya, Ikeda, Yujiro, Takeuchi, Hiroshi, JAERI-Research 2001-007, 1, 42, Mar. 2001
循環水の放射化を利用したD-T中性子モニターの技術的成立性に関する実験的研究をITER R&Dタスクとして行った。FNSのD-T中性子源を用いて、パルス中性子に対する時間分解能を調べたところ、10.7m/sの流速において50msの時間分解能が得られた。またITERのブランケット領域の中性子場を模擬するためにステンレス綱/水体系内に水ループを挿入して、中性子束の測定精度の検証実験を行った。その結果、測定誤差は10%以下であり、ITER用中性子モニターとして利用可能であることを示した。, English

A Study on 14MeV neutron beam characteristics and its applications　　　　　　　　　　　　　　　
Sakane, H, Uno, Yoshitomo, Maekawa, Fujio, Kasugai, Yoshimi, Konno, Chikara, Kaneko, Junichi, Ikeda, Yujiro, Reactor Dosimetry: Radiation Metrology and Assessment (ASTM STP 1398), 375, 382, 2001
原研FNSの14-MeV単色中性子源にコリメータ及び遮蔽体を設置し、14-MeV中性子ビームを利用可能にした。遮蔽体は鉄製プリコリメータ(厚さ50cm)及び鉄(120cm)、ポリエチレン(40cm)、カドミニウム(100cm)、鉛(20cm)からなるメインコリメータで構成されており、コリメータ径は2cmである。コリメータ出口における中性子ビーム特性をシンチレーション検出器やイメージングプレートにより実験的に、またMCNPコードによる計算で調べた結果、最大14-MeV中性子束は約2$times$10$^{6}$n/cm$^{2}$/sであり、これと比較してビーム領域外では中性子束が4桁以上低いこと、及びビーム中の14-MeV中性子成分の割合は99.9%以上に達することが分かった。応用の一例として2次$gamma$線生成断面積測定を行い、従来のパルス中性子に比べて2桁以上効率の良い測定が実現できた。また優れた近接性や低バックグラウンドが達成されていることが示され、今後の利用が期待される。, English

Mechanical alloying over three decades and aluminum based materials
KANEKO Junichi, 軽金属, 50, 5, 237, 245, 30 May 2000
軽金属学会, Japanese

Extremely short-lived excited-state complex and stimulated emission observed in ion irradiated ionic crystals
KIMURA K., KANEKO J., SHARMA S., ITOH N., Meeting abstracts of the Physical Society of Japan, 53, 2, 864, 864, 05 Sep. 1998
The Physical Society of Japan (JPS), Japanese

A new 100 ps-lived luminescence component and stimulated emission from ion irradiated α-alumina
KIMURA K., KANEKO J., SHARMA Sumit, ITOH N., Meeting abstracts of the Physical Society of Japan, 53, 2, 236, 236, 05 Sep. 1998
The Physical Society of Japan (JPS), Japanese

Development of Radiation Detectors using Synthetic Diamond Crystals　　　　　　　　　　　　　　　
Proceedings of the 5th NIRIM International symposium on advanced materials, ISAM '98, 257, 260, 1998

7p-H-10 A 100ps fast decay component of a time- resolved luminescence spectrum of α-alumina excited at high density by energetic ions
Kimura K., kaneko J., Itoh N., Meeting abstracts of the Physical Society of Japan, 52, 2, 240, 240, 16 Sep. 1997
The Physical Society of Japan (JPS), Japanese

6a-YC-5 Luminescence and Decay Measurement on Ion-irradiated Synthetic Diamond Crystals
Kimura K., Kaneko J., Meeting abstracts of the Physical Society of Japan, 52, 2, 863, 863, 16 Sep. 1997
The Physical Society of Japan (JPS), Japanese

NEUTRON SPECTROMETERS FOR ITER　　　　　　　　　　　　　　　
Diagnostics for Experimental Thermonuclear Fusion Reactors, Proceedings of the International Workshop on Diagnostics for ITER, Aug. 28 - Sept. 1, 0, 1995

ダイヤモンドエレクトロニクスの最前線　　　　　　　　　　　　　　　
シーエムシー出版, 2008

Frontier of Diamond for Electronics Applications　　　　　　　　　　　　　　　
CMC books, 2008

放射線計測　　　　　　　　　　　　　　　
第4章第3節第4項、"ダイヤモンド検出器"、p.p. 130-131.
国際文献社, [Joint work]

TlBr中の電荷捕獲準位解明と全吸収γ線エネルギースペクトロメータ開発への挑戦
科学研究費助成事業 基盤研究(C)
01 Apr. 2021 - 31 Mar. 2024
金子 純一, 人見 啓太朗
TlBrの原材料精製、単結晶育成をすすめた。4Nグレードの原材料を帯域精製中心に純化し、TlBr単結晶を育成した。このTlBr単結晶から検出器を作製し、共同研究先である東北大学と共同して電荷キャリア輸送特性等の評価を進めた。
原材料精製、単結晶育成技術に各種改良を重ねた結果、電荷収集効率が大幅に改善した。精製や単結晶育成時の雰囲気に関する改良を段階的に進めると共に、帯域精製に関しては安定して300回の精製を行っている。単結晶育成も同様に信頼性のある炉の開発に成功した。世界的な半導体不足の影響を受け、装置開発が大分遅れたが、年度内に予定していた装置の改良は概ね完了した。
662keVγ線を使用した実験では全吸収ピークがまだ立っていないことから、欠陥低減に加え、電極作製方法等の改善を今後進める。特に加工方法に関してはこれまでのアプローチを肯定する成果を得られたものと判断している。また電荷捕獲トラップを検証するための光照射I-V測定装置の開発も概ね予定通り進んでいる。直径0.5"のTlBr単結晶が安定して合成可能となったことから、今後の各種実験の進展も期待できる。


今後は5Nグレードの原材料の使用なども予定しており、従来行ってきた欠陥低減や電極に関する実験を積極的に進め、実用的なTlBr半導体検出器の実現を目指す。さらに安定して測定が可能となったカソードルミネッセンス法に加え、光I-V測定により捕獲準位の定量的な研究に切り込んでいく。
日本学術振興会, 基盤研究(C), 北海道大学, 21K12532

遮蔽不要な臨界近接監視システム用ダイヤモンド中性子検出器の要素技術開発　　　　　　　　　　　　　　　
英知を結集した原子力科学技術・人材育成推進事業
Oct. 2020 - Mar. 2023
田中真伸, 金子純一
文部科学省, 課題解決型廃炉研究プログラム（一般研究））, 大学共同利用機関法人高エネルギー加速器研究機構, Coinvestigator

過酷事故対応電子機器の実用化に向けた耐放射線・高温動作半導体デバイスの高性能化　　　　　　　　　　　　　　　
原子力システム研究開発事業
Oct. 2020 - Mar. 2023
梅沢仁、金子純一
文部科学省, ボトルネック課題解決型, 国立研究開発法人産業技術総合研究所, Coinvestigator

耐放射線性ダイヤモンド半導体撮像素子の開発　　　　　　　　　　　　　　　
英知を結集した原子力科学技術・人材育成推進事業
Oct. 2019 - Mar. 2022
大曲 新矢, 金子純一
文部科学省, 共通基盤型原子力研究プログラム, 国立研究開発法人産業技術総合研究所, Coinvestigator

Realization of Cherenkov PET with photon-electron hybrid detectors using transparent semiconductors
Grants-in-Aid for Scientific Research
28 Jun. 2019 - 31 Mar. 2021
Hitomi Keitaro
Thallium bromo-chloride (TlBrCl) is a transparent semiconductor. TlBrCl crystals were grown by the traveling molten zone method using zone-purified materials in this study. Semiconductor detectors were fabricated from the TlBrCl crystals by evaporating electrodes on the crystals. A TlBr0.7Cl0.3 semiconductor detector exhibited an energy resolution of 6.4% full width at half maximum for 511-keV gamma rays at room temperature. A silicon photomultiplier (SiPM) was coupled optically to a TlBr0.3Cl0.7 semiconductor detector. The TlBr0.3Cl0.7 detector was irradiated with a 22Na gamma-ray source at room temperature. The gamma ray interacting with the detector material creates electron-hole pairs and Cherenkov photons simultaneously in the crystal. Simultaneous detection of the charge signal and the photon signal was achieved with the device in this study. The TlBrCl detectors are attractive for applications in positron emission tomography.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Tohoku University, 19K22942

原子炉計装の革新に向けた耐放射線・高温動作ダイヤモンド計測システムの開発とダイヤモンドICの要素技術開発　　　　　　　　　　　　　　　
原子力システム研究開発事業
Oct. 2016 - Mar. 2020
金子純一
文部科学省, 安全基盤技術研究開発, 北海道大学, Principal investigator

Research and development of the next generation diamond pixel sensor
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
01 Apr. 2016 - 31 Mar. 2019
Tanaka Manobu, KOIZUMI satoshi, SHIMAOKA takahiro
The development of a diamond detector with the charge collection efficiency(CCE) of ~100% was done, and the process requirements for developing a pixel detector based on diamond basis achieves less than 100-micron meter position resolution are investigated. Since the radiation tolerant transistors are necessary to integrate signal processing circuits on the pixel detector, total integrated dose characteristics of transistors are evaluated and confirmed those transistors have radiation resistivity more than 0.3MGy.
A trend of accelerators R&D is high intensity/luminosity. From the viewpoint of the detection system, the radiation resistivity and the fast response are required. Si-based detectors are insufficient for the purpose. Diamond-based detectors can solve the problems. We succeeded to develop diamond detectors for those requirements and established the TCAD numerical model which can reproduce the I-V characteristics, the bias dependence of the CCE and the current signal waveform.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), High Energy Accelerator Research Organization, 16H03990

Development of a micro RI dynamic imaging system for living cells
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
01 Apr. 2016 - 31 Mar. 2018
Yamaya Taiga, NISHIKIDO Fumihiko, NAKANISHI Takayuki
Studies on cell regulation are attracting worldwide attention in order to realize regenerative medicine. Therefore, a nuclear medicine imaging method, which can use tracers having substantially the same composition as a target biomolecule, is required. In this research, we developed a nuclear medicine imaging system for dynamic cell observation. Specifically, in order to prevent broadening of the scintillation position because of scintillation light spreading in the scintillator, beta-rays are detected by a thin scintillator plate. A scientific CMOS camera with low readout noise and high resolution was used to detect scintillation light. The scintillator plate was a CsI crystal (150 micron thick) connected to an optical fiber (6 micron diameter) array. The scintillation light generated from the scintillator plate was extracted through optical fibers. Imaging results showed that our system has sufficient sensitivity for imaging uptake of fluorodeoxyglucose by single cells.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, National Institutes for Quantum and Radiological Science and Technology, 16K12886

Trial for neutron dosimetry from the atomic level by use of Diamond NV centers
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
01 Apr. 2015 - 31 Mar. 2017
kaneko junichi, ONODA Shinobu, TUBOTA Masakatsu, TANAKA Manobu, SHIMAOKA Takehiro, SHINMYO Akihiro, HIRANO Shintaro, MIZUKOSHI Tsukasa
In this study, we investigated the feasibility of atomic scale neutron dosimetry by measuring NV center in diamond which is generated by fast neutron irradiation and trace nitrogen in crystals by annealing. The sample was prepared by adding a trace amount of nitrogen during synthesis using microwave plasma CVD method. The sample after neutron irradiation or electron beam irradiation showed a strong increase of NV center, and density could not be quantified. NV center was concentrated on the growth surface side. This may be showed that the incorporation of nitrogen was large at the completion of synthesis. In order to perform dosimetry, it is necessary for nitrogen to be incorporated uniformly throughout the sample, so optimization of nitrogen uptake during CVD synthesis is indispensable.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 15K14286

Development of wide gap semiconductor pixel detector for light dark matter search
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
01 Apr. 2013 - 31 Mar. 2016
Tanaka Manobu, KANEKO Junichi, SHIMAOKA Takehiro, OHSHIMA Takeshi, MAKINO Takakahiro, MIUCHI Kentaro
We developed pixel detectors based on wide gap semiconductor materials(i.e. diamond and silicon carbide) for light dark matter search. The wide gap semiconductor containing carbon improves the sensitivity for light dark matter search.
The electrode size of the detectors is about 100um x 100um. The detector shows two or three orders of magnitudes leakage reduction compared to a silicon pixel detector, and the detector capacitance of the diamond pixel is one half the silicon pixel detector. We confirmed developed pixel detectors have enough S/N for our purpose.
In order to evaluate the detectors low noise front-end integrated circuit is developed.The equivalent noise charge(ENC) is less than 100 electron which satisfies S/N for our evaluation of the detectors.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), High Energy Accelerator Research Organization, 25400308

Development of the separation of nuclides by using nano-diamonds
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
01 Apr. 2012 - 31 Mar. 2016
WATANABE Masayuki, KANEKO Junichi
In this study, we had focused on the adsorption of metal cation onto diamond surface. Objectives of this study is to elucidate the mechanism on the adsorption of rare earth cations, which is contained into the high level liquid waste generated by reprocessing spent nuclear fuels. Based on the dependence of acidity on the distribution coefficient of rare earth cations, and analysis of the adsorption isotherms and/or adsorption capacity, the adsorption of rare earth is mono-layer plain adsorption and the 1:1 stoichiometric proportion of the adsorption with ionic bonding nature.
The investigation by XPS, FT-IR and TRLFS indicated the consistent results with the mechanism which stated above.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Japan Atomic Energy Agency, 24561045

Development of an inexpensive screening radiation detector for confidence in food
Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research
01 Apr. 2012 - 31 Mar. 2014
KANEKO Junichi, TAKADA Eiji
Confidence in food was required after broad area radiation contamination caused by nuclear accident in the Fukushim Daiichi nuclear power plant. In this study, an inexpensive radiation detector measuring radioactivity for retail shops and/or direct marketing farmers. This detector was designed to made best use of self-shielding of food itself. In size of 1.25 x 1.25 x 3.0 cm^3 of CsI(Tl) scintillator was assumed, and it was reveled to achieve screening level of 50 Bq/kg within 22 minute for rice in 5 kg. In addition, it took only several minutes to determine that radioactivity is lower than 100 Bq/kg.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 24658113

Development of radiation detectors based on crystal growth of CVD single diamond combined with a lift-off method
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
2010 - 2012
KANEKO Junichi, FUJITA Fumiyuki, SHIKATA Shinichi, SASAO Mamiko, SATO Satoshi, ISOBE Mitsutaka, NAKAI Mitsuo, ASANO Yoshihiro, ISHIKAWA Masazumi
Growth condition of CVD diamond single crystals were optimized. Radiation detectors were fabricated form the grown CVD diamonds; then induced charge collection distribution measurement for the detectors were carried out by use of alpha particles. Charge collection efficiency of 100 % and 97 %, μτ values of 1×10-4 and 9.6×10-6 cm2/V for holes and electrons were achieved by one of the best detectors. In addition, energy resolution of 3.5 % at a peak caused by the 12C(n, alpha)9Be reactions were obtained in response function measurement for 14 MeV neutrons. Fast time resolution of 350 ps was also achieved for 8 GeV electron beams.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 22360395

Study on change of transmission cross sections and development of new application field in spectroscopic imaging using a pulsed neutron transmission method
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
2008 - 2010
KIYANAGI Yoshiaki, FURUSAKA Michihiro, KAMIYAMA Takashi, MOCHIKI Kohichi, HIRAGA Fujio, KANEKO Junichi, IWASE Kenji, HARADA Masahide, OOI Motoki, SATO Setso, SAGEHASHI Hidenori
It has been clarified that texture in metals reflects the neutron transmission cross section and the world's first analysis code for deducing quantitative information of the texture, crystallite size and strain has been developed. By using this code texture and crystallite size of a welded iron were investigated, and also texture, crystallite size and strain of iron during in-situ tensile test were successfully imaged. Furthermore, a camera system applicable to a pulsed neutron source has been developed.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 20246136

CVD単結晶ダイヤモンド合成に基づくDT中性子エネルギースペクトロメータの開発
科学研究費助成事業 特定領域研究
2008 - 2009
金子 純一, 藤田 文行, 本間 彰
今年度は前年度良い結果の出たリフトオフ法を北海道大学に導入することを第一目標として研究を行った。Ib型基板を使用して連携研究先である産業技術研究所と同一の合成条件でCVD単結晶の合成を行った。合成した試料をリフトオフ法により自立膜化した。さらに化学処理ならびに電極製作を行い、検出器とした。製作した検出器に対してI-V測定、α線応答測定を行った。十分な印加電圧がかかり、α線に対して16%程度ではあるがピークの立つ応答を示す検出器の製作に成功した。今後、高品質基板を使用し、合成条件の最適化を進め実用的な人工ダイヤモンド放射線検出器の実現を目指す。
また合成した結晶中の電荷捕獲準位を同定するための積極的電荷捕獲を利用した光I-V測定法の改良をすすめ、ある程度信頼性のあるデータが取得できる状況に達した。
日本学術振興会, 特定領域研究, 北海道大学, 20026001

Improvement of Quantification in PET and Development of a Noninvasive Blood Radioactivity Monitor
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
2007 - 2009
KUBO Naoki, KATOH Chietsugu, KANEKO Jyunichi, KIMURA Ayaka, NAKAMARU Hiroshi
We have investigated a new noninvasive blood-radioactivity monitor. The monitor estimates the input functions for quantitative PET by sequentially measuring the radioactivity of the radial artery. Thus, we indicated that a PET scan is more comfortable for patients.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 19591394

Basic Research for four-dimensional stereotactic radiotherapy
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Priority Areas
2005 - 2009
SHIRATO Hiroki, KANEKO Junichi, NISHIYAMA Syusuke, KATOH Chietsugu, AOYAMA Hidefumi, SEKI Koh-ichi, ONIMARU Rikiya, NISHIOKA Takeshi, MORITA Koichi, DATE Hiroyuki, TAKADA Eiji, TOMIOKA Satoshi, KUDO Kohsude, ONODERA Yuya, KAMISHIMA Tamotsu, ONIMARU Rikiya, SHIMIZU Shinichi, SAKUHARA Yusuke, OYAMA Noriko, ABO Daisuke, TAGUCHI Hiroshi
We developed a four-dimensional (4-D, space and time) focal positron emission localizer, FPEL, using two sets of BGO scintillators, photo-electric multiplier, and collimators. A narrow (5-mm in diameter) 45-MeV electron beam was controlled to irradiate a target with an accuracy of 0.1mm in 4D coordinates automatically if the amount of positron emitters at the target exceeds the threshold. A mouse model was established to irradiate the tumor in which FDG is accumulated. Using the FPEL, 45-MeV electron beam hit the tumor in mice which move in front of the beam exit with the amplitude resembling human respiration. Tumor without fiducial gold marker disappeared within a week after the irradiation. Basis for 4D stereotacic radiotherapy was established successfully.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research on Priority Areas, Hokkaido University, 17016002

The formation process of a new ordered structure in complex plasmas
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C)
2007 - 2008
FUJITA Fumiyuki, FURUSAKA Michihiro, KANEKO Junnichi, NISHIYAMA Shuusuke
定在縞を持つ陽光柱プラズマという秩序状態に、外部から微粒子を導入することでコンプレックスプラズマとする。このプラズマにおける新たな秩序状態(プラズマクリスタル)形成過程を実測し、データ解析を行った。安定な結晶が生成される放電条件で放電させておき、直径10μmの微粒子を落下させると、プラズマ内で微粒子の浮遊が起こり、次いで"気体または液体状態"となり、落下後数十秒以内でプラズマクリスタル状態へ移行していくことを観測した。この新たな秩序の形成過程を評価するために、画像データから対相関関数(動径分布関数)を求めるアルゴリズムを開発した。
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, 19540389

Interactive Radiotherapy
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
2006 - 2008
SHIRATO Hiroki, HONMA Sato, TAMAKI Nagara, KUGE Yuji, DATE Hiroyuki, KIYANAGI Yoshiaki, HATAKEYAMA Masanori, KANEKO Junichi, MIZUTA Masahiro, INUBUSHI Masayuki, TADANO Shigeru, TAMURA Mamoru, HAYAKAWA Kazushige, MATSUNAGA Naofumi, ISHIKAWA Masayori, AOYAMA Hidefumi, SAKUHARA Yusuke, ONIMARU Rikiya, ABO Daisuke, OITA Masataka, KAMISHIMA Tamotsu, TERAE Satoshi, KUDO Kohsuke, ONODERA Yuya, OMATSU Tokuhiko, SHIMIZU Shinichi, NISHIMURA Takashi, SUZUKI Ryusuke, GERARD Bengua
いままでの先端放射線医療に欠けていた医療機器と患者のinteractionを取り入れた放射線治療を可能にする。臓器の動き・腫瘍の照射による縮小・免疫反応などは、線量と時間に関して非線形であり、システムとしての癌・臓器の反応という概念を加えることが必要であることが示唆された。生体の相互作用を追求していく過程で、動体追跡技術は先端医療のみならず、基礎生命科学でも重要な役割を果たすことがわかった。
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 18209039

DT中性子計測への応用をめざしたCVD単結晶ダイヤモンド厚膜の合成と評価
科学研究費助成事業 特定領域研究
2006 - 2007
金子 純一, 藤田 文行, 本間 彰, 藤森 直治
今年度は人工ダイヤモンド放射線検出器実現を目指し、CVD単結晶ダイヤモンド厚膜の合成と評価を行った。高圧高温合成Ib型基板を使用し、800度・1100度、80Torr・110Torrの4点でダイヤモンドを合成した。合成の主目的はダイヤモンドの{111}面の成長率と{100}面の成長率の比であるα値の把握である。α値によって結晶のモルフォロジーや不純物の取り込みに大きな違いが生じることが知られている。
合成したダイヤモンドのα値は1.6〜4.9に分布した。ラマン分光の結果、全ての試料でダイヤモンドのsp^3結合によるピークが観測された。800度で合成した試料についてはグラファイト成分、窒素と空孔のペアによるNV発光が観測された。また、これら二つの試料については、結晶表面上に平行電極を蒸着により製作し印加電圧をかけた状態でα線を入射させた。この結果、α線により生成した電荷キャリアのドリフトにより信号が出ることを確認した。
さらに、高品質なダイヤモンドの合成を目指し、800度、110Torr、メタン濃度1%での合成をおこなった。その結果、ラマン分光ではグラファイト、NV発光は観測されなかったが、多結晶体的な表面形態をもった結晶であり、α線測定については漏れ電流が大きく信号が出なかった。
今年度の研究の結果、α値3〜4の範囲を集中的にサーベイを行なう必要があるとの結論に至った。次年度以降は低メタン濃度における長時間合成を行なっていく。
日本学術振興会, 特定領域研究, 北海道大学, 18035001

New Material Characterization method by Using a pulsed Neutron Transmission Spectroscopic Radiography
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
2005 - 2007
KIYANAGI Yoshiaki, KAMIYAMA Takashi, KANEKO Jyunichi, TOMIOKA Satoshi, TAKENAKA Nobuyuki, FURUSAKA Michihiro
Spectroscopic neutron radiography using a pulsed neutron can give structural information of materials since it has neutron cross section data at each pixel. Especially, at low energy region of the cross section Bragg edges appear which reflect the crystal structure of the materials. The shift of the Bragg position gives strain of the crystal. We performed the experiment on the iron sample which would have strain due to bending. We could clearly observe the strain position and amount of the strain. It was found that the strain appeared on specific crystal planes. It is also indicated that the total neutron cross section around the Bragg edge depended on the grain size of the crystalitte and showed that the cross section decreased proportional to the grain size by a model experiment. Furthermore, the crystal structural change around the welded position of the SS-Iron sample and Iron-Iron sample. The crystal structure change had similar tendency in both sample. Naturally, far from the weld position the cross section showed the typical feature of Bragg edges of iron and SS, as approaching the weld position the edge became sharper, and at weld position the edge had a sharp edge implying the isotropic distribution of the crystallittes. On the other hand, at high energy we can utilize the resonance absorption to get image of elements or nuclei. We performed transmission measurement of the heavy material to get CT image, and it is suggested that the method was also useful for imaging the element distribution and also that we may use this to measure the temperature by analyzing the resonance peak. We developed the sensor of the imaging detector based on Gd composite. We succeeded in making a test detector and also obtained images by using the neutron beam.
As mentioned above, the spectroscopic neutron imaging using the pulsed neutron sources are very powerful tool to investigate micro structure of the materials, such as strain, crystallite size, distribution of crystallite and so on. Now, the operation of the big proton accelerator neutron source is just about to take place. We will get much higher quality data by using such high intensity sources and also get much detailed information about the sample materials. Therefore, we are now on the stage to develop the method further to promote the industrial applications.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 17206096

Development of neutron phase space transfer optical devices
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
2005 - 2007
KANEKO Junichi, FURUSAKA Michihiro, FUJITA Fumiyuki, KIYANAGI Yoshiaki, KAMIYAMA Takashi, OTAKE Yoshie
Changes in neutron intensity and diffraction angle form a vibrating quartz single crystal were investigated by a 2D neutron detector and time-of-flight method.
A X-cut quartz single crystal in size of 3mm×120mm×14mm was used in an experiment. Quartz single crystal has polarization according to a X-axis, thus, perpendicular cut to this axis, I.e., X-cut has the largest displacement. Bias voltage of 40 V was applied to aluminum electrodes fabricated on the quartz crystal, and it was moved in the characteristic vibration frequency of 22.7 kHz. Maximum displacement of c.a. 5μm was observed using a microscope.
A neutron diffraction experiment was carried out on the ULS (Ultra Small angle neutron scattering) system in JRR-3M; neutron beam of wavelength of 4.7 angstrom was used. A combination of a ZnS:Li scintillator and a position sensitive photo multiplier was used as a neutron detector. Neutron diffraction patterns were obtained with a vibrating quartz single crystal in 22.7 kHz; change of neutron diffraction patterns according to vibration period. Neutron intensity had two strong components. Velocity of 4.7 angstrom neutrons are c.a. 840 m/s, thus they move 1.8 cm in 44μs, I.e., a half of the vibration period. By change of 1.8 cm in position of the detector, neutron intensity was changed according to phase shifting in pi.
Experimental results were compared with theoretical estimation. In the case of displacement caused by the Doppler effect was larger than that caused by deformation, experimental results of time dependence of diffracted neutrons' intensity were suit for a theoretical result.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 17360448

DT中性子計測への応用を目指した高品質単結晶ダイヤモンドの合成と特性評価
科学研究費助成事業 特定領域研究
2005 - 2005
金子 純一, 藤田 文行
本研究では二つのテーマについて研究を行った。一つ目のテーマである高品質単結晶ダイヤモンドの合成と評価では、超高純度原料をもちいた高圧高温合成単結晶ダイヤモンドの合成と評価を行い非ダイヤモンド原料を使った場合、結晶性に問題が生じる可能性があること、現状の技術ではHP/HT法によってエネルギースペクトロメータグレードの単結晶ダイヤモンドを造ることはペンディングとすべきであるものの、CVD単結晶合成用の基板としては極めて有望であることを明らかにした。また高品質CVD単結晶ダイヤモンドの合成と評価を行った結果、透明な大面積基板は歩留まりよく合成可能であるものの電気特性向上を狙った合成条件の探求が必要であることがわかった。
二つ目のテーマである電荷捕獲準位同定手法の開発では試料に対する電荷捕獲をあらかじめ行ったうえで、光電流測定を行い、捕獲準位のエネルギー同定を行う測定方法確立の目処を立てた。紫外線とWランプからの単色光を用いた不純物準位の評価技術の開発を行い、超高純度HP/HTダイヤモンド及びCVDダイヤモンドの計測を行った。外気導入による冷却によって試料温度を0℃付近まで下げることで熱雑音を1桁減らし、数100fAの電流計測を可能にした。この方法は従来に無い極めて優れた方法であり、高品質ダイヤモンド合成のために完成を目指すべき手法といえる。
日本学術振興会, 特定領域研究, 北海道大学, 17044001

Development of layered type CVD single aystal diamond radiation detectors
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
2003 - 2004
KANEKO Junichi, SAWAMURA Teruko, ITO Toshimichi, TERAJI Tokuyuki
In this fiscal year, improvement on fabrication of layred type CVD diamond radiation detectors. In the previous year, we tried to fabricate the layred type CVD single diamond radiation detector by using a high-quality boron doped diamond layer that was flat in atom scale. However, this trial was failed because abnormal growth on the boron doped layer. Thus, we applied previously used process for fabrication of boron-doped layer. In this process, we found out that grown diamond layer obtained large influence from surface morphology of a type Ib single diamond substrate. Then, we evaluate a relation between mechanical polishing process and grown diamond layer. In previously used process, type Ib diamond substrate mechanically polished for one direction was used. Recently a diamond substrate supplier changed their way to polish a diamond substrate. The supplier polished a diamond substrate from random directions in order to obtained better optical flatness. However, this process destroyed surface crystal structure, and it resulted in bad quality in grown diamond layer. Then we asked to change the substrate supplier for their polishing process for suitable way to diamond growth, and it resulted in better growth of diamond layer. In addition, we tried to fabricate a layered type CVD diamond radiation detector by using high-quality single diamond substrate. This substrate include only 0.1 to 0.3 ppm of boron impurities and it was semiconductor. Moreover, charge carriers' transport phenomenon measurement system 213 nm UV pulse laser system was developed. Charge carriers' transport phenomenon in the layered type diamond radiation detectors, single and polycrystalline diamond were evaluated by using this system. 14 MeV neutron response function measurements using the layered type CVD single diamond radiation detector was carried out.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 15360498

Development of high efficiency pursed neutron source by using a new material of methane hydrate
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
2002 - 2004
KIYANAGI Yoshiaki, KAMIYAMA Takashi, HIRAGA Fujio, SAWAMURA Teruko, KANEKO Junichi, FURUSAKA Michihiro
Methane hydrate has been expected as a cold neutron moderator material giving higher intensity over wide energy range. We have performed experimental studies mainly. We measured neutron inelastic scattering at ISIS in UK to know the neutron cross-section characteristics. The methane molecule in methane hydrate seemed to rotate freely since the rotational energy level was 1.1meV which is almost same as the energy level of free rotation of methane. We could deduce the translational modes in the small and large ice cages. The ice vibrational mode and librational mode in methane hydrate were almost similar to those of ice In although there existed small distortion. These data suggested that methane hydrate cross section can be simulated linear combination of cross sections of both materials. As a moderator the effect of methane is important but the content of methane is not so high in methane hydrate.
So, we performed moderator experiments to observe the neutronic performance of methane hydrate. We studied a coupled and a decoupled moderators. Methane and hydrogen moderator data were also obtained fro the comparison. In the case of the coupled moderator, the shape of the energy spectrum of methane hydrate was similar to that of ice, the peak energy of methane hydrate moderator was little bit higher than those of other materials of methane and hydrogen. Spectral intensity around the cold neutron region was much lower than other materials. However, around the thermal neutron region the intensity was higher. In the case of the decoupled moderator the spectral intensity was approaching that of hydrogen moderator but much lower than methane. The pulse width of emission time was much wider than other moderators. Therefore, it will be concluded that the methane hydrate moderator does not have so good characteristics as a cold moderator and can give higher intensity at higher energy region.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 14380229

医用原子力　　　　　　　　　　　　　　　
2004
Competitive research funding

Nuclear engineering for radiation therapy and diagnostics　　　　　　　　　　　　　　　
2004
Competitive research funding

中性子散乱実験用高速・高位置分解能二次元中性子検出器開発のための基礎研究
科学研究費助成事業 萌芽研究
2002 - 2003
金子 純一, 片桐 政樹
今年度は前年度行なったGd金属箔の検出効率が思うように上がらなかったことから、Gd系シンチレータの薄膜化とMCPの組み合わせについて実験的に研究を進めた。Gd金属箔からの内部転換電子は1方向へのみ放出された分がMCPに入射可能となる。一方、Gd系シンチレータを使用した場合は、内部転換電子がシンチレータ内で光に変換されるため、光の取り出しを上手く行なうことで4π方向に出た内部転換電子を全て捉えることができる。この方法をもちいた場合、最大の問題となるのがMCPが直接γ線や中性子線と反応することである。この部分については北大ライナックならびに高エネルギー加速器研究機構KENSにおける実験を行い、MCPが直接反応した場合の信号の減衰時間(数ns)とシンチレータの減衰時間(数10ns)程度の違いをもちいて弁別できることを確認した。またシンチレータの薄膜化については、今後さらに進める必要があるものの、焼結手法によって中性子をほぼ100%捕獲し、γ線の影響を最低限に抑えられる30μmの厚さを得るめどを立てた。このシンチレータは焼結条件によって発光強度と透明度が変わることが分かっている。この部分については今後、合成条件の最適化をすすめる必要がある。本研究は今年度で終了するが、Gd系シンチレータとMCPを組み合わせることで、中性子イメージングを行なえる基礎的実証データを積み上げることに成功し、初期の目的を達成することが出来た。今後、さらに100μm以下の位置分解能をもち、残留応力測定等に使える中性子イメージング装置の開発につなげていく必要がある。
日本学術振興会, 萌芽研究, 北海道大学, 14658142

酸化物シンチレータの開発　　　　　　　　　　　　　　　
2001
Competitive research funding

development of oxide scintillators　　　　　　　　　　　　　　　
2001
Competitive research funding

中性子散乱実験用中性子検出器・中性子光学素子の開発　　　　　　　　　　　　　　　
1999
Competitive research funding

Development of neutron detectors and neutron optics　　　　　　　　　　　　　　　
1999
Competitive research funding

人工ダイヤモンド放射線検出器の開発　　　　　　　　　　　　　　　
1994
Competitive research funding

Development of synthetic diamond radiation detectors　　　　　　　　　　　　　　　
1994
Competitive research funding

放射線計測方法及び放射線計測装置
Patent right, 井▲崎▼ 賢二, 森下 祐樹, 山崎 巧, 金子 純一, 樋口 幹雄, 坪田 陽一, 山本 誠一, 石橋 浩之, 国立研究開発法人日本原子力研究開発機構, 国立大学法人北海道大学
特願2015-028396, 17 Feb. 2015
特開2016-151454, 22 Aug. 2016
特許第6524484号, 17 May 2019
201903002078894496

単結晶、放射線検出器及び放射線検出器の使用方法
Patent right, 石橋 浩之, 志村 直明, 金子 純一, 坪田 陽一, 樋口 幹雄, 西山 修輔, 株式会社オキサイド, 国立大学法人北海道大学
特願2014-029357, 19 Feb. 2014
特開2015-151535, 24 Aug. 2015
特許第6303146号, 16 Mar. 2018
201803004677560666

シンチレータプレート、放射線計測装置、放射線イメージング装置およびシンチレータプレート製造方法
Patent right, 金子 純一, 樋口 幹雄, 嶋岡 毅紘, 坪田 陽一, 井崎 賢二, 国立大学法人北海道大学, 国立研究開発法人日本原子力研究開発機構
特願2013-507801, 30 Mar. 2012
特許第5971866号, 22 Jul. 2016
201603007274739059

ダイヤモンド半導体デバイス
Patent right, 金子 純一, 坪田 雅功, 梅澤 仁, 鹿田 真一, 坪内 信輝, 小泉 聡, 国立大学法人北海道大学, 国立研究開発法人産業技術総合研究所, 国立研究開発法人物質・材料研究機構
特願2014-265640, 26 Dec. 2014
特開2016-127088, 11 Jul. 2016
201603014067241039

動的腫瘍の放射線治療装置および動的腫瘍の放射線治療プログラム
Patent right, 金子 純一, 白土 博樹, 藤田 文行, 高田 英治, 国立大学法人北海道大学, 独立行政法人国立高等専門学校機構
特願2009-500232, 21 Feb. 2008
WO2008-102843, 28 Aug. 2008
特許第5113828号, 19 Oct. 2012
201303010798437287

単結晶シンチレーター
Patent right, 上田 俊輔, 石橋 浩之, 蔵重 和央, 金子 純一, 樋口 幹雄, 川村 宗範, 佐伯 掌平, 日立化成工業株式会社, 国立大学法人 北海道大学
特願2008-050385, 29 Feb. 2008
特開2009-074039, 09 Apr. 2009
200903012738634458

入力関数測定装置　　　　　　　　　　　　　　　
Patent right
特許公開２０１１－６４６６１

小型Ｘ線発生装置　　　　　　　　　　　　　　　
Patent right
特許公開２００９－２８３１６９

単結晶シンチレータ　　　　　　　　　　　　　　　
Patent right
特願2008-050385

動的腫瘍の放射線治療装置および動的腫瘍の放射線治療プログラムム(PCT/JP2008/052944)　　　　　　　　　　　　　　　
Patent right
特願2007-041373

中性子線検出器　　　　　　　　　　　　　　　
Patent right
特開２００４－１８４１０４

高速・高位置分解能型中性子検出用ガスカウンタ計測システム　　　　　　　　　　　　　　　
Patent right
特許公開２００２－６２３６０