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Oda, Chie; Honda, Akira; Takase, Hiroyasu*; Ozone, Kenji*; Sasaki, Ryoichi*; Yamaguchi, Kohei*; Sato, Tsutomu*
Nendo Kagaku, 51(2), p.34 - 49, 2013/02
Proposed TRU repository designs for geological disposal envisage the use of a bentonite buffer to limit the migration of radionuclides by impeding groundwater flow. Under highly alkaline conditions due to cementitious materials could cause a complex series of coupled changes in the porewater chemistry, mineralogy and, ultimately, the mass transport properties of the bentonite buffer. To elucidate the consequences of these coupled changes, reactive-transport model analyses have been conducted for eight bentonite alteration test cases using different combinations of secondary minerals that could form in the bentonite buffer. It was found that after 100,000 years the amount of dissolved bentonite was at a maximum when metastable secondary minerals precipitated. It was also found that the diffusion and hydraulic coefficients after 100,000 years in all test cases were on the same order of magnitude as the initial values.
Odaka, Hirokazu*; Ichinohe, Yuto*; Takeda, Shinichiro*; Fukuyama, Taro*; Hagino, Koichi*; Saito, Shinya*; Sato, Tamotsu*; Sato, Goro*; Watanabe, Shin*; Kokubun, Motohide*; et al.
Nuclear Instruments and Methods in Physics Research A, 695, p.179 - 183, 2012/12
Times Cited Count：23 Percentile：82.34(Instruments & Instrumentation)We have developed a new Si/CdTe semiconductor double-sided strip detector (DSD) Compton camera. The camera consists of a 500-
m-thick Si-DSD and four layers of 750-m-thick CdTe-DSDs all of which have common electrode configuration segmented into 128 strips on each side with pitches of 250m. In order to realize high angular resolution and to reduce size of the detector system, a stack of DSDs with short stack pitches of 4 mm is utilized to make the camera. Taking advantage of the excellent energy and position resolutions of the semiconductor devices, the camera achieves high angular resolutions of 4.5 degrees at 356 keV and 3.5 degrees at 662 keV. To obtain such high resolutions together with an acceptable detection efficiency, we demonstrate data reduction methods including energy calibration using Compton scattering continuum and depth sensing in the CdTe-DSD. We also discuss imaging capability of the camera and show simultaneous multi-energy imaging.
-ray cameraTakeda, Shinichiro*; Ichinohe, Yuto*; Hagino, Koichi*; Odaka, Hirokazu*; Yuasa, Takayuki*; Ishikawa, Shinnosuke*; Fukuyama, Taro*; Saito, Shinya*; Sato, Tamotsu*; Sato, Goro*; et al.
Physics Procedia, 37, p.859 - 866, 2012/10
Times Cited Count：25 Percentile：98.53(Physics, Applied)By using new Compton camera consisting of silicon double-sided strip detector (Si-DSD) and CdTe-DSD developed for the ASTRO-H mission, an experiment was conducted to study its feasibility for advanced hotspot monitoring. In addition to hotspot imaging already provided by commercial imaging systems, the identification of the variety of radioisotopes is realized thanks to the good energy resolution given by the semiconductor detectors. Three radioisotopes of 
Ba (356 keV), 
Na (511 keV) and 
Cs (662 keV) were individually imaged by applying event selection in the energy window and the -ray images was correctly overlapped by an optical picture. The detection efficiency of 1.68
10
(effective area: 1.710 cm
) and angular resolution of 3.8
were obtained by stacking five detector modules for 662 keV -ray. The higher detection efficiency required in a specific use can be achieved by stacking more detector modules.
Yamaguchi, Hiroyasu*; Shimizu, Akemi*; Hase, Yoshihiro; Degi, Konosuke*; Tanaka, Atsushi; Morishita, Toshikazu*
Euphytica, 165(1), p.97 - 103, 2009/01
Times Cited Count：29 Percentile：74.89(Agronomy)We compared the effects of ion-beam and -ray irradiation on mutation induction in axillary buds of chrysanthemum, and analyzed the chimeric structure of the resulting mutants. Axillary buds were irradiated with carbon ions (mean LET 122 keV/m), helium ions (9 keV/m), and rays. The lower five nodes of shoots elongating from the irradiated buds were cut one by one, and new shoots were allowed to grow. This procedure was repeated twice and flower color mutation was investigated. Chimeric structure was analyzed by comparing the flower color of mutants to that of plants regenerated from the roots. All the flower color mutants induced with rays were periclinal chimeras. In contrast, some mutants obtained with ion beams had the same flower color as that of the plants derived from the roots. This suggests that they were solid mutants, where both LI and LIII tissues were derived from the same mutated cell.
-rays; Guineagrass and sorghumNakagawa, Hitoshi*; Inafuku, Masashi*; Kusaba, Makoto*; Yamaguchi, Hiroyasu*; Morishita, Toshikazu*; Morita, Ryohei*; Nishimura, Minoru*; Hoeman, S.*; Yokota, Yuichiro; Hase, Yoshihiro; et al.
JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 72, 2008/03
no abstracts in English
rayMorita, Ryohei*; Morishita, Toshikazu*; Nakagawa, Hitoshi*; Nishimura, Minoru*; Yamaguchi, Hiroyasu*; Yokota, Yuichiro; Hase, Yoshihiro; Tanaka, Atsushi
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 78, 2007/02
no abstracts in English
rays with irradiation to rice seedYamaguchi, Hiroyasu*; Hase, Yoshihiro; Tanaka, Atsushi; Shikazono, Naoya; Degi, Konosuke*; Shimizu, Akemi*; Morishita, Toshikazu*
no journal, ,
no abstracts in English
Morita, Ryohei*; Yamaguchi, Hiroyasu*; Yokota, Yuichiro; Hase, Yoshihiro; Nishimura, Minoru*
no journal, ,
no abstracts in English
ray irradiation to lateral buds of chrysanthemumYamaguchi, Hiroyasu*; Shimizu, Akemi*; Hase, Yoshihiro; Tanaka, Atsushi; Degi, Konosuke*; Morishita, Toshikazu*
no journal, ,
no abstracts in English
rays irradiation in rice plantNishimura, Minoru*; Morita, Ryohei*; Kusaba, Makoto*; Yamaguchi, Hiroyasu*; Hase, Yoshihiro
no journal, ,
no abstracts in English
ray irradiation to lateral buds of chrysanthemumYamaguchi, Hiroyasu*; Shimizu, Akemi*; Hase, Yoshihiro; Tanaka, Atsushi; Degi, Konosuke*; Morishita, Toshikazu*
no journal, ,
no abstracts in English
Oda, Chie; Yamaguchi, Kohei; Savage, D.*; Benbow, S.*; Watson, C.*; Takase, Hiroyasu*
no journal, ,
Mudstones containing smectite have been altered under mildly alkaline conditions (9 
pH 10) at Searles Lake. This natural alteration has been investigated using reaction-transport modelling. These data demonstrate that smectite alteration will be controlled by the kinetics of dissolution-precipitation reaction and the salinity of the pore fluid.
irradiation in riceMorita, Ryuhei*; Kusaba, Makoto*; Yamaguchi, Hiroyasu*; Yokota, Yuichiro; Hase, Yoshihiro; Nishimura, Minoru*
no journal, ,
no abstracts in English
-rays and ion beamsNishimura, Minoru*; Morita, Ryuhei*; Yamaguchi, Hiroyasu*; Hase, Yoshihiro
no journal, ,
no abstracts in English
Okamura, Masachika*; Momose, Masaki*; Umemoto, Naoyuki*; Toguri, Toshihiro*; Tanaka, Atsushi; Hase, Yoshihiro; Yamaguchi, Hiroyasu*; Morishita, Toshikazu*
no journal, ,
no abstracts in English
-rays and ion beamsNishimura, Minoru*; Morita, Ryuhei*; Yamaguchi, Hiroyasu*; Hase, Yoshihiro
no journal, ,
no abstracts in English
rays in rice plantNishimura, Minoru*; Morita, Ryohei*; Yamaguchi, Hiroyasu*; Hase, Yoshihiro
no journal, ,
no abstracts in English
rays and ion beams irradiationMorishita, Toshikazu*; Shimizu, Akemi*; Yamaguchi, Hiroyasu*; Degi, Konosuke*; Mukasa, Yuji*; Aii, Jotaro*; Hase, Yoshihiro; Shikazono, Naoya; Tanaka, Atsushi; Miyazawa, Yutaka*; et al.
no journal, ,
no abstracts in English
raysMorita, Ryohei*; Morishita, Toshikazu*; Nakagawa, Hitoshi*; Nishimura, Minoru*; Yamaguchi, Hiroyasu*; Yokota, Yuichiro; Hase, Yoshihiro; Tanaka, Atsushi
no journal, ,
no abstracts in English
ray; Guinea grass and sorghumNakagawa, Hitoshi*; Inafuku, Masashi*; Kusaba, Makoto*; Yamaguchi, Hiroyasu*; Morishita, Toshikazu*; Morita, Ryohei*; Nishimura, Minoru*; Hoeman, S.*; Yokota, Yuichiro; Hase, Yoshihiro; et al.
no journal, ,
no abstracts in English
