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Nakanoya, Takamitsu; Yoshimoto, Masahiro; Saha, P. K.; Takeda, Osamu*; Saeki, Riuji*; Muto, Masayoshi*
Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.937 - 941, 2023/11
In the J-PARC 3GeV Rapid Cycling Synchrotron (RCS), the 400MeV H
beam is changed to H+ beam by a charge exchange foil and accelerated to 3GeV. So far, RCS had used two types of charge exchange foil. One is the HBC (Hybrid Boron mixed Carbon) foil and the other is the Kaneka GTF (Graphene Thin Film). HBC foil is a patented deposition method developed at KEK for the stable production of thick carbon foil. Initially, the RCS used HBC foil produced atKEK. However, in 2017, JAEA had started HBC foil production and has been using it since then. Recently, we have succeeded in depositing thick pure carbon foil, which had been considered difficult to produce by the arc deposition method. As a new challenge, this pure carbon foil was used in the user operation from March 2023. As a result, Pure carbon foils showed less deformation and more stable charge exchange performance than HBC and GTF.
Watanabe, Masashi; Yokoyama, Keisuke; Imai, Yoshiyuki; Ueta, Shohei; Yan, X.
Ceramics International, 48(6), p.8706 - 8708, 2022/03
Times Cited Count：7 Percentile：75.06(Materials Science, Ceramics)Previous studies have used various methods for sintering of SiC, carbon, and SiC/carbon functionally graded materials (FGM). However, no experimental studies on SiC/graphite FGM manufacturing using the spark plasma sintering (SPS) method have been reported. In this study, a SiC/graphite FGM specimen has been fabricated using SPS. The interface between the adjacent layers of the sintered specimen exhibits no apparent defects such as gaps or delaminations. The SiC and graphite phases in the specimen show no substantial change before and after sintering.
Shinohara, Koji; JT-60 Team
Journal of the Korean Physical Society, 49, p.S56 - S62, 2006/12
The recent results of JT-60, such as the long discharge with the high normalized beta of 2.3 and the pulse length of 22.3 s which was 13 times longer than the current profile relaxation, and the observation of the increase of D
emission and electron density as results of wall saturation will be reviewed. Additionally, the motivation and the design work will be reviewd on an on-going recent project of the ferritic insertion for the reduction of the toroidal field ripple. The pioneering works of JFT-2M in the ferritic insertion will be also reported.
Takenaga, Hidenobu; Nakano, Tomohide; Asakura, Nobuyuki; Kubo, Hirotaka; Konoshima, Shigeru; Shimizu, Katsuhiro; Tsuzuki, Kazuhiro; Masaki, Kei; Tanabe, Tetsuo*; Ide, Shunsuke; et al.
Nuclear Fusion, 46(3), p.S39 - S48, 2006/03
Times Cited Count：18 Percentile：52.46(Physics, Fluids & Plasmas)no abstracts in English
Nakamura, Hirofumi; Higashijima, Satoru
Shinku, 49(2), p.62 - 68, 2006/02
no abstracts in English
Uno, Sadanori; Takayama, Terumitsu*; Koka, Masashi*; Mizuhashi, Kiyoshi
Dai-18-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.133 - 136, 2005/11
no abstracts in English
Masnavi, M.*; Nakajima, Mitsuo*; Sasaki, Akira; Hotta, Eiki*; Horioka, Kazuhiko*
Applied Physics Letters, 87(11), p.111502_1 - 111502_3, 2005/09
Times Cited Count：4 Percentile：17.87(Physics, Applied)no abstracts in English
Oda, Yasuhisa*; Ushio, Masato*; Komurasaki, Kimiya*; Takahashi, Koji; Kasugai, Atsushi; Sakamoto, Keishi
AIP Conference Proceedings 766, p.297 - 302, 2005/04
no abstracts in English
Takenaga, Hidenobu; Asakura, Nobuyuki; Higashijima, Satoru; Nakano, Tomohide; Kubo, Hirotaka; Konoshima, Shigeru; Oyama, Naoyuki; Isayama, Akihiko; Ide, Shunsuke; Fujita, Takaaki; et al.
Journal of Nuclear Materials, 337-339, p.802 - 807, 2005/03
Times Cited Count：14 Percentile：67.84(Materials Science, Multidisciplinary)no abstracts in English
Takenaga, Hidenobu; Nakano, Tomohide; Asakura, Nobuyuki; Kubo, Hirotaka; Konoshima, Shigeru; Shimizu, Katsuhiro; Tsuzuki, Kazuhiro; Ide, Shunsuke; Fujita, Takaaki
Proceedings of 4th IAEA Technical Meeting on Steady-State Operation of Magnetic Fusion Devices and MHD of Advanced Scenarios (Internet), 8 Pages, 2005/02
no abstracts in English
Kusama, Yoshinori; Ishikawa, Masao; Takechi, Manabu; Nishitani, Takeo; Morioka, Atsuhiko; Sasao, Mamiko*; Isobe, Mitsutaka*; Krasilnikov, A.*; Kaschuck, Y.*
Proceedings of Plasma Science Symposium 2005/22nd Symposium on Plasma Processing (PSS-2005/SPP-22), p.395 - 396, 2005/00
The energetic neutral particles have been successfully measured with a natural diamond detector in the neutron and 
ray radiation circumstance of the JT-60U deuterium discharges. The diamond detector was covered with polyethylene and lead in order to reduce the neutron and ray background. The shield has shown expected shielding capability. A rapid increase in neutral particles has been observed at the onset of the Toroidal Alfven Eigenmode (TAE) excited by the negative-ion-based neutral beam injection. The energy range of increased neutral particles has agreed well with that predicted from the resonant interaction between the energetic ions and the TAE.
Masnavi, M.*; Nakajima, Mitsuo*; Sasaki, Akira; Hotta, Eiki*; Horioka, Kazuhiko*
Japanese Journal of Applied Physics, 43(12), p.8285 - 8291, 2004/12
Times Cited Count：5 Percentile：23.97(Physics, Applied)no abstracts in English
Asakura, Nobuyuki
Plasma Physics and Controlled Fusion, 46(12B), p.B335 - B347, 2004/12
Times Cited Count：18 Percentile：51.27(Physics, Fluids & Plasmas)Particle control of the main plasma density and exhaust of impurities ions have been demonstrated using the divertor pumping under saturated divertor condition. In JT-60U, ELMy H-mode operation was recently extended to 30s (with NB heating of 8-14 MW). Total number of injected particles reached (1-4)x1023 to maintain high densities. During the long pulse ELMy H-mode of JT-60U, gas puff rate was decreased from 15 to 3Pam3/s, while pumping rate was relatively constant of ~10 Pam3/s. Thus, the divertor plate was mostly saturated. It was found that 40-50% of the injected D was retained, which are comparable to Tore-Supra long pulse and JET high density ELMy H-mode pulse. Particle balance for long pulse and/or high density plasmas are discussed. Carbon flux generated by the chemical process was increased due to increase in the target temperature. Carbon generation and carbon ion emission were gradually increased in the outer leg of the divertor and the X-point. Shielding effect of the divertor was sustained and increment of the radiation power fraction was small in 30s.
Goto, Yoshitaka*; Arai, Takashi; Yagyu, Junichi; Masaki, Kei; Kodama, Kozo; Miya, Naoyuki
Journal of Nuclear Materials, 329-333(1), p.840 - 844, 2004/08
Times Cited Count：15 Percentile：68.2(Materials Science, Multidisciplinary)TEM and Selected Area Diffraction (SAD) were made on nm-structures of redeposition layers on graphite tiles used in the lower-X-point divertor of JT-60. The tiles were used in the 1988 experimental campaign in which 300 divertor discharges and 1500 limiter discharges were made. TEM observations were made at poloidal and/or toroidal sections at two positions on the inboard side of the inner-separatrix strike point. Layer structures in 0-6micron depths were correlated to the last 40-shots in the campaign. Columnar structures corresponded to divertor discharges of additional heating power below 10MW. Lamellar structures were due to limiter discharges or to the higher power divertor discharges. Carbon-Mo, Ti or carbon-Ni, Fe, Cr, Ti codeposition layers were ascribed to disruptive shots. From analyses on poloidal orientation of the column axes and graphene sheets composing columns, the observed columnar structures were ascribed to both low adatom-migration due to the low deposition temperatures and also to self-shadowing effects due to inclined incidence of carbon impurity ions.
Uno, Sadanori; Tajima, Satoshi; Takada, Isao; Takayama, Terumitsu*; Koka, Masashi*; Moriya, Yoshinori*; Ebina, Tetsuya*
Dai-16-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.75 - 79, 2004/02
no abstracts in English
Okano, Fuminori; Suzuki, Sadaaki
KEK Proceedings 2003-16 (CD-ROM), 4 Pages, 2004/02
A JFT-2M Tokamak auxiliary subsystem consists of a vacuum pumping system, a gas injection system, a leak detection system, a water cooling system, a glow discharge system, a boronization system, and a baking system. Control system of each part except for the baking system was replaced to new one, which utilizes a personal computer (PC), from FY 2000 to FY2002. The controllability of the system and the number of data, which can be recorded, was remarkably improved compared to the old system. This system has enough controllability for various operation condition of JFT-2M, and allows early finding and recovering of troubles. The general view of Tokamak auxiliary subsystem and detailed description of the function of the new control system are given in this report. It should be noted that this report describes detail of the operational procedure especially for He glow discharge system and the boron coating system, and thus, it can be used as an operation instruction.
Takano, Shoji*; Totsuka, Toshiyuki; Yonekawa, Izuru
KEK Proceedings 2003-16 (CD-ROM), 4 Pages, 2004/02
no abstracts in English
Horikawa, Toyohiko*; Kaminaga, Atsushi; Nakamura, Hirofumi; Higashijima, Satoru; Arai, Takashi; Kubo, Hirotaka; Konishi, Satoshi*; Nishikawa, Masabumi*
JAERI-Tech 2003-082, 66 Pages, 2003/12
JAERI-Tech-2003-082.pdf:3.44MB
no abstracts in English
Okano, Fuminori; Suzuki, Sadaaki
JAERI-Tech 2003-059, 57 Pages, 2003/06
JAERI-Tech-2003-059.pdf:11.92MB
no abstracts in English
Ozu, Akira; Ito, Kazunori*
Journal of Applied Physics, 93(12), p.9477 - 9482, 2003/00
Times Cited Count：5 Percentile：24.25(Physics, Applied)no abstracts in English
