New muonium HFS measurements at J-PARC/MUSE

Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12

https://doi.org/10.1007/s10751-016-1331-4

A Development of super radiation-hardened power electronics using silicon carbide semiconductors; Toward MGy-class radiation resistivity

Hijikata, Yasuto*; Mitomo, Satoshi*; Matsuda, Takuma*; Murata, Koichi*; Yokoseki, Takashi*; Makino, Takahiro; Takeyama, Akinori; Onoda, Shinobu; Okubo, Shuichi*; Tanaka, Yuki*; et al.

Proceedings of 11th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-11) (Internet), p.130 - 133, 2015/11

Radioactive waste management in O-arai Research and Development Center

Maeda, Atsushi; Kowata, Koichi; Yamazaki, Yasuo; Takahashi, Kozo; Okubo, Toshiyuki; Miyazaki, Hitoshi

Dekomisshoningu Giho, (33), p.58 - 66, 2006/03

http://www.randec.or.jp/publish/documents/gihou/Decommissioning%20gihou_33.pdf

By the Japan Atomic Energy Agency (JAEA), designed decommissioning of nuclear facility and the treatment and disposal of radioactive waste will be carried out systematically and efficiently as responsibility as the installer of the nuclear power facility and generator of radioactive waste. This paper shows the present status of radioactive waste management in O-arai Research and Development Center, one of the research and development bases of JAEA. The management of low-level radioactive waste, including those accepted from outside operator of O-arai district, is carried out by the major premise of ensuring safety at O-arai Waste Management Facility. Treatment related to volume reduction and stabilization by means such as incineration and compression of solid waste, and solidification of liquid, as well as waste storage management is steadfastly promoted, so that these substances may be adequately stored and managed until they are disposed of.

Wether investigation report

Torii, Tatsuo; OKUBO, Koichi; Okuyama, Shinichi

JNC TN4420 2004-002, 14 Pages, 2004/05

JNC-TN4420-2004-002.pdf:0.36MB

none

Monju

Iwama, Toshiro; Okubo, Koichi; Okuyama, Shinichi

JNC TN4420 2003-003, 30 Pages, 2004/03

JNC-TN4420-2003-003.pdf:2.18MB

none

Quasi-two dimensional electronic state of the antiferromagnet UPtGa

Ikeda, Shugo; Tokiwa, Yoshifumi*; Haga, Yoshinori; Yamamoto, Etsuji; Okubo, Tomoyuki*; Yamada, Mineko*; Nakamura, Noriko*; Sugiyama, Kiyohiro*; Kindo, Koichi*; Inada, Yoshihiko*; et al.

Journal of the Physical Society of Japan, 72(3), p.576 - 581, 2003/03

https://doi.org/10.1143/JPSJ.72.576

no abstracts in English

Electrical properties of SiC MOSFETs irradiated with -rays at elevated temperature

Matsuda, Takuma; Yokoseki, Takashi; Mitomo, Satoshi; Murata, Koichi; Makino, Takahiro; Takeyama, Akinori; Onoda, Shinobu; Okubo, Shuichi*; Tanaka, Yuki*; Kandori, Mikio*; et al.

no journal, , 

Silicon carbide (SiC) is expected to be applied to Metal-Oxide-Semiconductor (MOS) FETs used in harsh radiation environments to decommission TEPCO Fukushima Daiichi nuclear reactors. To develop radiation resistant SiC MOS FETs, clarification of their radiation response under elevated temperature is required. We measured capacitance-voltage (C-V) characteristics of SiC MOSFETs irradiated with -rays at 423 K in nitrogen atmosphere. The samples were vertical power 4H-SiC MOSFETs with the blocking voltage of 1200 V and the rated current of 20 A with the gate oxide thickness of 45 nm. Typical C-V curve of a SiC MOSFET irradiated even up to 5 kGy was shifted to negative voltage side, suggesting that the positive charges generated in gate oxide by irradiation. While, no significant change in the slope of the curve was observed, indicating that interface traps between the gate oxide and SiC were merely generated. The radiation response of SiC MOS FETs under elevated temperature predominantly depends on the amount of positive charges generated in the gate oxide.

Influence of gate bias on -ray radiation response of SiC MOSFETs

Takeyama, Akinori; Murata, Koichi*; Mitomo, Satoshi*; Matsuda, Takuma*; Yokoseki, Takashi*; Makino, Takahiro; Onoda, Shinobu; Okubo, Shuichi*; Tanaka, Yuki*; Kandori, Mikio*; et al.

no journal, , 

Deterioration of electrical property of SiCMOSFETs due to irradiation was reduced compared with no biased ones, when the SiC MOSFETs with switching bias were irradiated. In order to clarify this mechanism, SiCMOSFETs were irradiated up to 50 kGy with switching bias applied to gate oxide from 4.5 to 0 V. As a result, the large negative shift of threshold voltage V due to irradiation with positive bias significantly recovered in the cases that the bias switched to zero. It shows electrical property of SiCMOSFETs were immediately relieved when applied bias was removed by switching.

Development of position assessment methods for atmospherically-released radioactivity, 2; Implementation for higher count rate situations

Takata, Takushi*; Ishizuka, Akihiro; Nozaki, Tatsuo; Kokubun, Yuji; Okubo, Koichi; Torii, Tatsuo; Kume, Kyo*; Otani, Nobuo*; Hasegawa, Takashi*

no journal, , 

The assessment methods of a radioactivity distribution unexpectedly released to atmosphere from nuclear power plants have been studied using a single channel analyzing technique. A combination of this single channel analyzing technique and a detector sensitive to a solid angle of an incident -ray was examined to assess the same purpose.

R&D project on irradiation damage management technology for structural materials of long-life nuclear plant; R&D of irradiation damage indicator and irradiation damage management

Wakai, Eiichi; Takada, Fumiki; Takaya, Shigeru; Kato, Shoichi; Kitazawa, Sin-iti; Okubo, Nariaki; Suzudo, Tomoaki; Fujii, Kimio; Yoshitake, Tsunemitsu; Kaji, Yoshiyuki; et al.

no journal, , 

no abstracts in English