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Oshima, Katsumi; Oda, Yasuhisa; Takahashi, Koji; Terakado, Masayuki; Ikeda, Ryosuke; Hayashi, Kazuo*; Moriyama, Shinichi; Kajiwara, Ken; Sakamoto, Keishi
JAEA-Technology 2015-061, 65 Pages, 2016/03
JAEA-Technology-2015-061.pdf:24.28MB
In JAEA, an ITER relevant control system for ITER gyrotron was developed according to Plant Control Design Handbook. This control system was developed based on ITER CODAC Core System and implemented state machine control of gyrotron operation system, sequential timing control of gyrotron oscillation startup, and data acquisition. The operation of ITER 170 GHz gyrotron was demonstrated with ITER relevant power supply configuration. This system is utilized for gyrotron operation test for ITER procurement. This report describes the architecture of gyrotron operation system, its basic and detailed design, and recent operation results.
Oda, Yasuhisa; Oshima, Katsumi; Nakamoto, Takashi*; Hashimoto, Yasunori*; Yamamoto, Tsuyoshi; Hayashi, Kazuo*; Ikeda, Yukiharu; Ikeda, Ryosuke; Kajiwara, Ken; Takahashi, Koji; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 90(7), p.365 - 373, 2014/07
no abstracts in English
traps in 6H-SiC studied with Laplace deep level transient spectroscopyKoizumi, Atsushi*; Markevich, V. P.*; Iwamoto, Naoya; Sasaki, Sho*; Oshima, Takeshi; Kojima, Kazutoshi*; Kimoto, Tsunenobu*; Uchida, Kazuo*; Nozaki, Shinji*; Hamilton, B.*; et al.
Applied Physics Letters, 102(3), p.032104_1 - 032104_4, 2013/01
Times Cited Count：11 Percentile：44.13(Physics, Applied)Iwamoto, Naoya*; Koizumi, Atsushi*; Onoda, Shinobu; Makino, Takahiro; Oshima, Takeshi; Kojima, Kazutoshi*; Koike, Shumpei*; Uchida, Kazuo*; Nozaki, Shinji*
Materials Science Forum, 717-720, p.267 - 270, 2012/05
Times Cited Count：1 Percentile：54.7(Materials Science, Multidisciplinary)In this study, we carried out an attempt to identify the defects responsible for the degraded charge collection efficiency of the 6H-SiC p
n diode irradiated with 1 MeV electrons by the alpha particle induced charge transient spectroscopy. To form defects in the SiC crystal, one of the diodes was irradiated with 1 MeV electrons at a fluence of 1
10
/cm
. Collected charges of the diodes were measured in room temperature using 5.486 MeV alpha particles from 
Am source. After the electron irradiation, the collected charge of the diode at a reverse bias of 100 V decreased to 84% of its initial value. In order to investigate the relationship between degradation of collected charge and defects in detail, time-dependent collected charges of the diodes were measured in temperature ranges from 170 K to 310 K. As a result, two distinct peaks labeled X
and X
are found for the electron-irradiated diode, and their activation energies are estimated to be 0.30 and 0.47 eV, respectively. These two peaks are considered to correspond to the defect levels introduced by the electron irradiation. In particular, when the diodes are used in room temperature, X is more critical to the charge collection than X.
n diode irradiated with high-energy electronsIwamoto, Naoya; Koizumi, Atsushi*; Onoda, Shinobu; Makino, Takahiro; Oshima, Takeshi; Kojima, Kazutoshi*; Koike, Shumpei*; Uchida, Kazuo*; Nozaki, Shinji*
IEEE Transactions on Nuclear Science, 58(6), p.3328 - 3332, 2011/12
Times Cited Count：5 Percentile：38.65(Engineering, Electrical & Electronic)no abstracts in English
Iwamoto, Naoya; Onoda, Shinobu; Makino, Takahiro; Oshima, Takeshi; Kojima, Kazutoshi*; Koizumi, Atsushi*; Uchida, Kazuo*; Nozaki, Shinji*
IEEE Transactions on Nuclear Science, 58(1), p.305 - 313, 2011/02
Times Cited Count：10 Percentile：60.88(Engineering, Electrical & Electronic)no abstracts in English
n diodes measured using alpha particlesIwamoto, Naoya; Onoda, Shinobu; Makino, Takahiro; Oshima, Takeshi; Kojima, Kazutoshi*; Koizumi, Atsushi*; Uchida, Kazuo*; Nozaki, Shinji*
Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.222 - 225, 2010/10
N diodes degraded by low-energy electron irradiationIwamoto, Naoya; Onoda, Shinobu; Oshima, Takeshi; Kojima, Kazutoshi*; Koizumi, Atsushi*; Uchida, Kazuo*; Nozaki, Shinji*
Materials Science Forum, 645-648, p.921 - 924, 2010/00
Electron irradiation effects on the charge collection efficiency (CCE) of the 6H-SiC pn diodes were investigated. The diodes were irradiated with electrons at energies from 100 keV to 1 MeV. The value of CCE of the diodes using alpha particles compared before and after the electron irradiations. In the case of 100 keV electron, no significant change in CCE was observed. On the other hand, above 200 keV, the values of CCE decreased with increasing fluence. The degradation was larger with increasing incident electron energy.
Oshima, Takeshi; Lee, K. K.; Ishida, Yuki*; Kojima, Kazutoshi*; Tanaka, Yasunori*; Takahashi, Tetsuo*; Yoshikawa, Masahito; Okumura, Hajime*; Arai, Kazuo*; Kamiya, Tomihiro
Materials Science Forum, 457-460(Part2), p.1405 - 1408, 2004/06
The electrical characteristics of cubic silicon carbide (3C-SiC) Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) with the current direction in the inversion layer perpendicular to [-110] ([-110]-perpendicular MOSFETs) were compared to those of 3C-SiC MOSFETs with the current direction in the inversion layer parallel to [-110] ([-110]-parallel MOSFETs). The threshold voltage (V
) for both MOSFETs shows -0.5 V although enhancement type MOSFETs were designed. The values of channel mobility which was estimated from linear region of drain current (I
) - drain voltage (V) curves are 230 cm/Vs for [-110]-perpendicular MOSFETs and 215 cm/Vs for [-110]-parallel MOSFETs, indicating no significant difference between both MOSFETs. The value of I for [-110]-perpendicular MOSFETs is of order of 10-8 A at V = 10V and gate voltage (V
) of -2V. However, for [-110]-parallel MOSFETs, I shows of order of -10-6 A at V = 10V and V = -2V.
Oshima, Takeshi; Lee, K. K.; Ishida, Yuki*; Kojima, Kazutoshi*; Tanaka, Yasunori*; Takahashi, Tetsuo*; Yoshikawa, Masahito; Okumura, Hajime*; Arai, Kazuo*; Kamiya, Tomihiro
Japanese Journal of Applied Physics, Part 2, 42(6B), p.L625 - L627, 2003/06
Times Cited Count：39 Percentile：77.43(Physics, Applied)The n-channel Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs) were fabricated on cubic silicon carbide (3C-SiC) epitaxial layers grown on 3C-SiC substrates. The gate oxide of the MOSFETs was formed using pyrogenic oxidation at 1100
C. The 3C-SiC MOSFETs showed enhancement type behaviors after annealing at 200C for 30 min in argon atmosphere. The maximum value of the effective channel mobility of the 3C-SiC MOSFETs was 260 cm/Vs. The leakage current of gate oxide was of a few tens of nA/cm at an electric field range below 8.5 MV/cm, and breakdown began around 8.5 MV/cm.
Nakanishi, Yasuo*; Wakahara, Akihiro*; Okada, Hiroshi*; Yoshida, Akira*; Oshima, Takeshi; Ito, Hisayoshi; Nakao, Setsuo*; Saito, Kazuo*; Kim, Y. T.*
Nuclear Instruments and Methods in Physics Research B, 206, p.1033 - 1036, 2003/05
Times Cited Count：18 Percentile：74.43(Instruments & Instrumentation)Photo luminescence properties of GaN implanted with Eu ions were studied. The GaN was epitaxialy grown on sapphire substrate. Multiple-implantation at RT was done to form box profile of Eu at a mean Eu concentration from 2.810
to 2.810
/cm
. Samples were annealed in NH
, N at 900-1050C for 5-30 min after implantation. As the result, sharp emission peaks around 621nm which is assigned as 4f-4f transition were observed. The intensity of peaks increases with increasing Eu concentration and saturate at Eu concentrations around 2.810/cm.
Shinohara, Nobuo; Kono, Nobuaki; Suyama, Kenya; Inagawa, Jun; Nakahara, Yoshinori; Kurosawa, Setsumi; Watanabe, Kazuo; Usuda, Shigekazu; Oshima, Masumi; Katsuta, Hiroji; et al.
Radiochimica Acta, 89(3), p.135 - 138, 2001/05
Times Cited Count：2 Percentile：19.66(Chemistry, Inorganic & Nuclear)no abstracts in English
Shimizu, Michio; Iwamatsu, Shigemi; Takada, Fumiki; Sozawa, Shizuo; Kawamata, Kazuo; Oshima, Kunio; Tsuchiya, Kunihiko; Yamaura, Takayuki; Matsui, Yoshinori; Iwai, Takashi; et al.
JAERI-Tech 2000-029, p.48 - 0, 2000/03
JAERI-Tech-2000-029.pdf:9.26MB
no abstracts in English
Saido, Masahiro; Fukuda, Mitsuhiro; Arakawa, Kazuo; Tajima, Satoshi; Sunaga, Hiromi; Yotsumoto, Keiichi; Kamiya, Tomihiro; Tanaka, Ryuichi; Hirao, Toshio; Nashiyama, Isamu; et al.
Proceedings of 1999 IEEE Nuclear and Space Radiation Effects Conference, p.117 - 122, 1999/00
no abstracts in English
Ikeda, Norio*; Sasaki, Nobuyuki*; Oshima, Kazuo*; Yamaguchi, Kohei*; Saito, Shigeyuki*; Abe, Yoriyuki*; Katano, Takashi*; Ueda, Akira*
JNC TJ7440 2005-071, 122 Pages, 1998/03
no abstracts in English
Shimono, Masato*; Motoshima, Takayuki*; Ijiri, Yuji*; Otsu, Hiroyasu*; Sakai, Ryosuke*; Sakai, Kazuo*; Sato, Toshinori; Mikake, Shinichiro
no journal, ,
It is considered that the uncertainty of construction cost due to geological heterogeneity is quite large. Therefore, it is crucial to make a long-term consistent budget plan for a construction period of tens years and to have engineering strategies for reducing a total budget. In this study, a risk management approach for construction in a heterogeneous fractured rock is developed. In this approach, methodologies of calculating construction costs for excavating drifts and taking countermeasures at high-hydrostatic pressured fracture zones in a heterogeneous rock are established. The cost for excavating drift is calculated from the heterogeneity of rock strength estimated from a geostatistical modeling approach. The cost for taking countermeasures is calculated from the heterogeneity of large fracture zone estimated from a probabilistic discrete fracture network modeling approach. In addition, a risk for a construction is assessed by a risk cost curve commonly used in the financial business.
-ray irradiation on electrical characteristics of SiC schottky barrier diodeKinoshita, Akimasa*; Tanaka, Yasunori*; Tanaka, Tomoyuki*; Fukuda, Kenji*; Arai, Kazuo*; Oshima, Takeshi; Hishiki, Shigeomi
no journal, ,
no abstracts in English
Iwamoto, Naoya; Onoda, Shinobu; Oshima, Takeshi; Kojima, Kazutoshi*; Koizumi, Atsushi*; Uchida, Kazuo*; Nozaki, Shinji*
no journal, ,
no abstracts in English
Iwamoto, Naoya; Onoda, Shinobu; Oshima, Takeshi; Kojima, Kazutoshi*; Koizumi, Atsushi*; Uchida, Kazuo*; Nozaki, Shinji*
no journal, ,
no abstracts in English
Iwamoto, Naoya; Onoda, Shinobu; Makino, Takahiro; Oshima, Takeshi; Kojima, Kazutoshi*; Koike, Shumpei*; Koizumi, Atsushi*; Uchida, Kazuo*; Nozaki, Shinji*
no journal, ,
no abstracts in English
