Nemoto, Fumiya*; Kofu, Maiko; Nagao, Michihiro*; Oishi, Kazuki*; Takata, Shinichi; Suzuki, Junichi*; Yamada, Takeshi*; Shibata, Kaoru; Ueki, Takeshi*; Kitazawa, Yuzo*; et al.
Journal of Chemical Physics, 149(5), p.054502_1 - 054502_11, 2018/08
Maebara, Sunao; Sukegawa, Keiichi*; Tadano, Shuya*; Kasugai, Atsushi; Suzuki, Hiromitsu; Abe, Kazuhiko*; Oku, Ryuji*; Sugimoto, Masayoshi
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1140 - 1142, 2015/09
For the IFMIF/EVEDA accelerator prototype RFQ linac, the operation frequency of 175MHz was selected to accelerate a large current of 125mA. The driving RF power of 1.28MW by 8 RF input couplers has to be injected to the RFQ cavity for CW operation mode. For each RF input coupler, nominal RF power of 160kW and maximum transmitted RF power of 200kW are required. For this purpose, an RF input coupler with cooling functions was designed, based on a 6 1/8 inch co-axial waveguide, and the RF coupler was manufactured by way of trial. For the trial RF coupler, high-power tests using a high voltage standing wave on a high-Q load circuit wave were carried out, and a 200kW-14 sec CW operation were performed after four days of RF aging. No RF contact defects, unnecessary low-Q value and extraordinary outgassing were observed. This report describes the high-power tests of the RF input coupler.
Knaster, J.*; Ibarra, A.*; Ida, Mizuho*; Kondo, Keitaro; Kikuchi, Takayuki; Ohira, Shigeru; Sugimoto, Masayoshi; Wakai, Eiichi; Watanabe, Kazuhito; 58 of others*
Nuclear Fusion, 55(8), p.086003_1 - 086003_30, 2015/08
The International Fusion Materials Irradiation Facility (IFMIF), presently in its Engineering Validation and Engineering Design Activities (EVEDA) phase under the frame of the Broader Approach Agreement between Europe and Japan, has accomplished in summer 2013, on schedule, its EDA phase with the release of the engineering design report of the IFMIF plant, which is here described. Many improvements of the design from former phases are implemented, particularly a reduction of beam losses and operational costs thanks to the superconducting accelerator concept. In the Test Cell design, the separation of the irradiation modules from the shielding block gaining irradiation flexibility and enhancement of the remote handling equipment reliability and cost reduction. The released IFMIF Intermediate Engineering Design Report, which could be complemented if required concurrently with the outcome of the on-going EVA carried out since the entry into force of IFMIF/EVEDA in June 2007, will allow the decision making on its construction and/or serve as the basis for the definition of the next step, aligned with the evolving needs of our fusion community.
Wakai, Eiichi; Kondo, Hiroo; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; Watanabe, Kazuyoshi; Ida, Mizuho*; Ito, Yuzuru; Niitsuma, Shigeto; Edao, Yuki; et al.
Fusion Science and Technology, 66(1), p.46 - 56, 2014/07
Tobita, Norimitsu; Yoshimoto, Masahiro; Yamazaki, Yoshio; Saeki, Riuji; Okabe, Kota; Kinsho, Michikazu; Takeda, Osamu*; Muto, Masayoshi*
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.915 - 919, 2014/06
The charge conversion foil used with a J-PARC 3GeV synchrotron (RCS: Rapid Cycling Synchrotron) is a thin film made from carbon about 1 micrometer thick, and it radioactivates it by continuing being irradiated with a beam. Moreover, generally it is thought that degradation progresses and foil itself breaks easily. However, when dealing with the foil after irradiation, the measure against the danger of the contamination and the contamination in the living body by foil dispersing is one of the subjects. So, in RCS, the foil exchange booth for collecting the radioactivated foil safely and certainly was installed. Even when dispersing foil temporarily, the radioactivated foil can be shut up only in Booth and a worker's contamination and contamination of work area could be prevented. Moreover, when it sees from a viewpoint of the performance gain of foil, analysis and observation of the collected foil are one of the important issues. Then, in order to observe the radioactivated foil after beam irradiation, the transparent protective case which can be sealed with a foil frame simple substance was developed. In this announcement, the equipment developed in order to collect the charge conversion foil after beam irradiation, and the established technique are announced in detail.
Saeki, Riuji; Yoshimoto, Masahiro; Yamazaki, Yoshio; Tobita, Norimitsu; Okabe, Kota; Kinsho, Michikazu; Takeda, Osamu*; Muto, Masayoshi*
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.523 - 526, 2014/06
RCS has loaded with the foil of 15 sheets including a reserve into equipment so that it can exchange in a short time, when foil is damaged also in a beam operating period. It is difficult for foil to be made of a thin film about 1 micrometer thick, and to treat as it is. Then, foil is fixed to the frame which stuck the SiC fiber, and foil is not touched, but only a frame is held, and it enabled it to operate it. The following preparations are needed as new foil exchange work. (1) Exfoliation and recovery of foil which have been vapor-deposited to glass substrate. (2) Dryness and logging of exfoliative foil. (3) Preparation of SiC wire, and attachment on frame. (4) Fix foil to a frame. (5) Although charge on a magazine-rack was performed manually altogether until now, there were many work man days, and the quality of the prepared foil had variation. Then, equipment required in order to secure reproducibility was developed. The technique for working efficiently simultaneously was established. In this announcement, the technique established until now and the developed jigs are announced in detail.
Tamura, Jun; Ao, Hiroyuki; Asano, Hiroyuki; Ikegami, Masanori*; Maruta, Tomofumi; Miura, Akihiko; Morishita, Takatoshi; Oguri, Hidetomo; Ouchi, Nobuo; Sawabe, Yuki*; et al.
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.377 - 380, 2013/08
In the J-PARC linac, almost all the cavities and magnets have been precisely aligned because the accelerator tunnel has been deformed by the 2011 Tohoku Earthquake. In the beam transport line called MEBT2 and A0BT at the downstream of the drift tube linac, the beam duct has been roughly aligned after the precise alignment of the quadruple doublets. During the first beam operation after the earthquake, remarkable beam loss and residual radiation have been recognized at the MEBT2 and A0BT. As the result of the duct position measurement, the misalignement including over 10 mm shift from the beam axis was found. By conducting the beam duct realignment, the beam loss and the residual radiation were successfully decreased. In this paper, the procedure of the beam duct alignment and the beam loss due to the misalignment are described.
Wakai, Eiichi; Kim, B. J.; Nozawa, Takashi; Kikuchi, Takayuki; Hirano, Michiko*; Kimura, Akihiko*; Kasada, Ryuta*; Yokomine, Takehiko*; Yoshida, Takahide*; Nogami, Shuhei*; et al.
Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 6 Pages, 2013/03
Yoneda, Yasuhiro; Kohara, Shinji*; Ito, Masayoshi*; Abe, Hiroshi; Takeuchi, Mitsuaki*; Uchida, Hirohisa*; Matsumura, Yoshihito*
Transactions of the Materials Research Society of Japan, 38(1), p.109 - 112, 2013/03
We performed local structure analysis of SmFe and TbFe in the crystallization process from amorphous by using synchrotron X-ray pair-distribution function (PDF) method. The giant mangetostrictive materials of these compounds can be controlled its property by ion irradiation. In amorphous TbFe and SmFe, the mosaic block size was small and the short-range order structure owing to Fe-Fe network maintained. In crystalline SmFe, a rigid long-range order structure of Fe-Fe and Sm-Sm network coexisted and it had a large mosaic block size. On the other hand, in crystalline TbFe, Fe-Fe network degraded by Tb-Tb network owing to its lattice tolerance.
Wakai, Eiichi; Kondo, Hiroo; Sugimoto, Masayoshi; Fukada, Satoshi*; Yagi, Juro*; Ida, Mizuho; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; Watanabe, Kazuyoshi; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 88(12), p.691 - 705, 2012/12
no abstracts in English
Katagiri, Hiromi; Okuno, Hiroshi; Sawahata, Masayoshi; Ikeda, Takeshi; Sato, Sohei; Terakado, Naoya; Nagakura, Tomohiro; Nakanishi, Chika; Fukumoto, Masahiro; Yamamoto, Kazuya; et al.
JAEA-Review 2011-037, 66 Pages, 2011/12
When a Nuclear emergency occurs, Nuclear Emergency Assistance & Training Center (NEAT) of JAEA gives technical advice and information, dispatch specialists as required, supplies emergency equipment and materials to the National Government and local governments. NEAT provides various lectures and training courses concerning nuclear disaster prevention for those personnel taking an active part in emergency response organizations at normal time. NEAT also researches on nuclear disaster prevention and cooperates with international organizations. Concerning about the assistance to the Accident of Fukushima No.1 Nuclear Power Station caused by the Great East Japan Earthquake at 11 March, 2011, JAEA assisted activities including environmental radiation monitoring, environmental radioactivity analyses, resident public consulting etc., with its full scale effort. NEAT served as the center of these supporting activities of JAEA.
Shibata, Yoshihide*; Watanabe, Kiyomasa*; Ono, Noriyasu*; Okamoto, Masaaki*; Isayama, Akihiko; Kurihara, Kenichi; Oyama, Naoyuki; Nakano, Tomohide; Kawano, Yasunori; Matsunaga, Go; et al.
Plasma and Fusion Research (Internet), 6, p.1302136_1 - 1302136_4, 2011/10
no abstracts in English
Shibata, Yoshihide*; Watanabe, Kiyomasa*; Okamoto, Masaaki*; Ono, Noriyasu*; Isayama, Akihiko; Kurihara, Kenichi; Nakano, Tomohide; Oyama, Naoyuki; Kawano, Yasunori; Matsunaga, Go; et al.
Nuclear Fusion, 50(2), p.025015_1 - 025015_7, 2010/01
no abstracts in English
Li, M.*; Nagashio, Kosuke*; Ishikawa, Takehiko*; Mizuno, Akitoshi*; Adachi, Masayoshi*; Watanabe, Masahito*; Yoda, Shinichi*; Kuribayashi, Kazuhiko*; Katayama, Yoshinori
Acta Materialia, 56(11), p.2514 - 2525, 2008/06
Co-61.8 at.% Si (CoSe-CoSi) eutectic alloys were solidified on an electromagnetic levitator (EML) and an electrostatic levitator (ESL) at different undercooling levels. The results indicated that there is only a single recalescence event at low undercooling with the CoSi intermetallic compound as primary phase, which is independent of processing facilities, on either an EML or an ESL. The microstructure, however, is strongly dependent on the processing facility. On high undercooling, double recalescence takes place regardless of levitation condition. In situ X-ray diffraction of alloys solidified on the EML demonstrates that the CoSi compound becomes the primary phase upon the first recalescence, and the CoSi intermetallic phase crystallizes during the second recalescence. In addition to phase identification, real-time diffraction patterns can also provide additional evidence of the fragmentation of the primary phase.
Sasao, Mamiko*; Kusama, Yoshinori; Kawano, Yasunori; Kawahata, Kazuo*; Mase, Atsushi*; Sugie, Tatsuo; Fujita, Takaaki; Fukuda, Takeshi*; Fukuyama, Atsushi*; Sakamoto, Yoshiteru; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 83(9), p.779 - 782, 2007/09
This is a report of highlights from 2007 spring meetings of seven Topical Groups (TG) of International Tokamak Physics Activity (ITPA). In each meeting, high priority issues in physics of International Thermonuclear Experimental Reactor (ITER) and other burning plasma experiments have been discussed and investigated. Twenty-seven scientists from Japan have participated in those meetings. Dates and places of the meetings are shown below. (1) Diagnostics TG: 26-30 March, Princeton (USA), (2) Transport Physics TG: 7-10 May, Lausanne (Switzerland), (3) Confinement Database and Modeling TG: 7-10 May, Lausanne (Switzerland), (4) Edge Pedestal Physics TG: 7-10 May, Garching (Germany) (5) Steady State Operation TG: 9-11 May, Daejeon (South Korea), (6)MHD TG: 21-24 May, San Diego (USA), (7) Scrape-off-layer and Divertor Physics TG: 7-10 May, Garching (Germany).
Takahashi, Kenji*; Sakai, Shingo*; Tezuka, Hiroaki*; Hiejima, Yusuke*; Katsumura, Yosuke; Watanabe, Masayoshi*
Journal of Physical Chemistry B, 111(18), p.4807 - 4811, 2007/05
Takamura, Shuichi*; Kado, Shinichiro*; Fujii, Takashi*; Fujiyama, Hiroshi*; Takabe, Hideaki*; Adachi, Kazuo*; Morimiya, Osamu*; Fujimori, Naoji*; Watanabe, Takayuki*; Hayashi, Yasuaki*; et al.
Kara Zukai, Purazuma Enerugi No Subete, P. 164, 2007/03
no abstracts in English
Kawahata, Kazuo*; Kawano, Yasunori; Kusama, Yoshinori; Mase, Atsushi*; Sasao, Mamiko*; Sugie, Tatsuo; Fujita, Takaaki; Fukuda, Takeshi*; Fukuyama, Atsushi*; Sakamoto, Yoshiteru; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 83(2), p.195 - 198, 2007/02
no abstracts in English
Nagashio, Kosuke*; Adachi, Masayoshi*; Higuchi, Kensuke*; Mizuno, Akitoshi*; Watanabe, Masahito*; Kuribayashi, Kazuhiko*; Katayama, Yoshinori
Journal of Applied Physics, 100(3), p.033524_1 - 033524_6, 2006/08
Grain refined microstructure is often obtained spontaneously in the solidification of metals and semiconductors from the undercooled melt without any external forces. Although it has been reported that the grain refinement is mainly caused by the fragmentation of the dendrites, the dynamic process of the fragmentation of dendrites has not been fully understood because the microstructure after the solidification has been analyzed. Here, we present a time-resolved 2- dimensional X-ray diffraction experiment on the solidification of Si from the undercooled melt. The number of diffraction spots observed at low undercoolings (100K) did not increase at the plateau stage, while the diffraction pattern at medium undercoolings (100K200K) changed from the spots with the tail to rings with the lapse of time. Both this result and high speed video imaging suggested that the high-order arms of the dendrites mostly detached from the main stems because nucleation could not be expected at the melting point after recalescence. The several spots observed at low undercoolings drastically changed to rings at high undercoolings (200K), which indicated the complete fragmentation of dendrite main stem as well as high-order arms. This complete fragmentation resulted in the grain refined microstructure.
Asakura, Nobuyuki; Kato, Takako*; Nakano, Tomohide; Takamura, Shuichi*; Tanabe, Tetsuo*; Iio, Shunji*; Nakajima, Noriyoshi*; Ono, Yasushi*; Ozeki, Takahisa; Takechi, Manabu; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 82(7), p.448 - 450, 2006/07
no abstracts in English