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Yamamoto, Kazami; Yamamoto, Masanobu; Yamazaki, Yoshio; Nomura, Masahiro; Suganuma, Kazuaki; Fujirai, Kosuke; Kamiya, Junichiro; Nakanoya, Takamitsu; Hatakeyama, Shuichiro; Yoshimoto, Masahiro; et al.
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.277 - 281, 2023/01
The J-PARC 3GeV Rapid Cycling Synchrotron (RCS) is aiming to provide the proton beam of very high power for neutron experiments and the main ring synchrotron. We have continued the beam commissioning and the output power from RCS have been increasing. In recent years, we have been trying continuous supply of 1-MW high-intensity beam, which is the design value, to a neutron target. We tried to operate continuously for over 40 hours in June 2020. However, some trouble occurred and the operation was frequently suspended. In June 2021, we tried again 1-MW operation but it was suspended due to deterioration of the cooling water performance. Last summer shutdown period, we recovered performance of the cooling water system and retried in this June. In the final case, the outside temperature became extremely high. We could not keep 1-MW power, whereas 600 kW beam was delivered in stable.
Takada, Hiroshi
JAEA-Conf 2017-001, p.51 - 56, 2018/01
A pulsed spallation neutron source of Japan Proton Accelerator Research Complex (J-PARC) is aimed at promoting a variety of cutting-edge materials researches at state-of-the-art neutron instruments with neutrons generated by a 3-GeV proton beam with a power of 1-MW at a repetition rate of 25 Hz. In 2015, for the first time it received 1-MW equivalent proton beam pulse, and the beam power for user program was ramped up to 500 kW. The moderator system of the neutron source was optimized to use (1) 100% para-hydrogen for increasing pulse peak intensity with decreasing pulse tail, (2) cylindrical shape with 14 cm diam. 
12 cm long for providing high intensity neutrons to wide neutron extraction angles of 50.8 degrees, (3) neutron absorber made from Ag-In-Cd alloy to make pulse widths narrower and pulse tails lower. As a result, it gives highest intensity pulsed neutrons per incident proton in the world. Towards the goal to achieve the target operation at 1-MW for 5000 h in a year, efforts to mitigate cavitation damages at the target vessel front with injecting gas micro-bubbles into the mercury target are under way. Also, improvement of structural target vessel design is an urgent issue since there was failure twice at the water shroud of the mercury target due to the thermal stress during operating periods at 500 kW in 2015.
Meigo, Shinichiro; Noda, Fumiaki*; Ishikura, Shuichi*; Futakawa, Masatoshi; Sakamoto, Shinichi; Ikeda, Yujiro
Nuclear Instruments and Methods in Physics Research A, 562(2), p.569 - 572, 2006/06
Times Cited Count：19 Percentile：77.5(Instruments & Instrumentation)no abstracts in English
Ikeda, Yujiro
Hamon, 15(1), p.6 - 9, 2005/01
The design status of the 1 MW spallation neutron source (JSNS) in the J-PARC project is to be described with an emphasis of the particular features in terms of structural components which form the central part of target station, Also, this article is expected to give a guide of which following sections are treating in specific technical issues such as spallation reactions, moderator neutronics and its technology, and radiation shielding.
Sakamoto, Shinichi; Meigo, Shinichiro; Konno, Chikara; Kai, Tetsuya; Kasugai, Yoshimi; Harada, Masahide; Fujimori, Hiroshi*; Kaneko, Naokatsu*; Muto, Suguru*; Ono, Takehiro*; et al.
JAERI-Tech 2004-020, 332 Pages, 2004/03
JAERI-Tech-2004-020.pdf:17.93MB
One of the experimental facilities in Japan Proton Accelerator Research Complex (J-PARC) is the Materials and Life Science Experimental Facility (MLF), where high-intensity neutron beams and muon beams are used as powerful probes for materials science, life science and related engineering. The neutrons and muons are generated with high-intensity proton beam from 3-GeV rapid cycling synchrotron (RCS). The high-intensity proton beam has to be effectively transported, and a neutron production target and a muon production target have to be also properly irradiated. The principal design of the 3-GeV proton beam transport facility (3NBT) is systematized.
Materials & Life Science Experimental Facility Construction Team
JAERI-Tech 2004-001, 1171 Pages, 2004/03
JAERI-Tech-2004-001-Part1.pdf:80.84MBJAERI-Tech-2004-001-Part2.pdf:43.14MB
This report summarizes conceptual design study up to March, 2003, relevant to the Materials & Life Science Experimental Facility construction which is one of the major user facilities to be constructed under the J-PARC project of High Intensity Proton Accelerator. The first chapter corresponds to the design manual, and the followings stand for the technical parts giving the design principle and detailed results for the studies. As the project is evolving day by day, some of studies have been advanced since the moment of this summary in one hand, and some of parts are close to final stage of design. Including those, more comprehensive and updated version of the technical designs are to be reported accordingly.
Nakagawa, Tatsuo*; Mihara, Yorichika*; Komurasaki, Kimiya*; Takahashi, Koji; Sakamoto, Keishi; Imai, Tsuyoshi
Journal of Spacecraft and Rockets, 41(1), p.151 - 153, 2004/02
Times Cited Count：40 Percentile：88.62(Engineering, Aerospace)A launching experiment of a microwave-boosted vehicle model was carried out using the 110GHz, 1MW gyrotoron and a propulsive inpulse to lift up the vehicle was measured. The rf power and pulse was 1MW and 0.175 
0.8msec. The launching mechanism is as follows. Plasma is produced in the nozzle of the vehicle model when the rf beam is injected toward it. The plasma heated by the rf beam can produce a shock wave that gives a propulsive impulse to the vehicle. Maximum momentum coupling coefficient from the impulse to the vehicle is 395N/MW which is comparable to that of a laser boosted vehicle. The rf pulse was 0.175msec. The coupling coefficient is limitted by the gyrtron operation in pulse length and can increase if the pulse length is shorter than 0.175msec.
Ikeda, Yujiro
Proceedings of ICANS-XVI, Volume 1, p.13 - 24, 2003/07
no abstracts in English
Takada, Hiroshi; Maekawa, Fujio; Honmura, Shiro*; Yoshida, Katsuhiko*; Teraoku, Takuji*; Meigo, Shinichiro; Sakai, Akio*; Kasugai, Yoshimi; Kanechika, Shuji*; Otake, Hidenori*; et al.
Proceedings of ICANS-XVI, Volume 3, p.1115 - 1125, 2003/07
no abstracts in English
Oda, Yasuhisa*; Nakagawa, Tatsuo*; Matsui, Makoto*; Komurasaki, Kimiya*; Takahashi, Koji; Sakamoto, Keishi; Imai, Tsuyoshi
Dai-47-Kai Uchu Kagaku Gijutsu Rengo Koenkai Koenshu (CD-ROM), p.1067 - 1069, 2003/00
no abstracts in English
Matsui, Makoto*; Mihara, Yorichika*; Nakagawa, Tatsuo*; Mori, Koichi*; Komurasaki, Kimiya*; Takahashi, Koji; Sakamoto, Keishi; Imai, Tsuyoshi
Uchu Yuso Shimpojiumu (Heisei-14-Nendo) Koenshu, p.300 - 303, 2003/00
no abstracts in English
Meigo, Shinichiro; Harada, Masahide; Konno, Chikara; Ikeda, Yujiro; Watanabe, Noboru; Sakamoto, Shinichi*; Muto, Suguru*; Miyake, Yasuhiro*; Nishiyama, Kusuo*; Shimomura, Koichiro*; et al.
JAERI-Conf 2001-002, p.314 - 324, 2001/03
no abstracts in English
Noda, Fumiaki*;
JAERI-Conf 2001-002, p.274 - 284, 2001/03
no abstracts in English
Minehara, Eisuke
JAERI-Conf 2000-019, p.115 - 116, 2001/02
no abstracts in English
Kasugai, Atsushi; Takahashi, Koji; Sakamoto, Keishi; *; Mitsunaka, Yoshika*; ; Ikeda, Yoshitaka; Tsuneoka, Masaki; Imai, Tsuyoshi
Proc. of 13th Topical Conf. on Applications of Radio Frequency Power to Plasmas, p.449 - 452, 1999/00
no abstracts in English
Mitsunaka, Yoshika*; Hirata, Yosuke*; Hayashi, Kenichi*; Ito, Yasuyuki*; Sakamoto, Keishi; Kasugai, Atsushi; Takahashi, Koji; Imai, Tsuyoshi
22nd International Conference on Infrared and Millimeter Waves Conference Digest, p.19 - 20, 1997/00
no abstracts in English
Maebara, Sunao; Tsuneoka, Masaki; Yokokura, Kenji; Honda, Masao; Sawahata, Masayuki; Sakamoto, Keishi; Seki, Masami; Ikeda, Yoshitaka; Miyake, Setsuo*
Plasma Devices and Operations, 1(2), p.141 - 154, 1991/10
no abstracts in English
; ; ; ; ; ; ; Saigusa, Mikio; ; ; et al.
Fusion Engineering and Design, 5, p.101 - 115, 1987/00
Times Cited Count：24 Percentile：88.58(Nuclear Science & Technology)no abstracts in English
Yamamoto, Kazami
no journal, ,
An accelerator system of Japan Proton Accelerator Research Complex (J-PARC) operated since May 2008 for neutron experiments. The accelerator system consists Linac, Rapid Cycling synchrotron (RCS) and Main Ring. The original design of RCS injection energy is 400 MeV, but first operation was started by 181 MeV for budget reason. New acceleration cavities were installed in J-PARC linac summer shutdown of 2013, and user operation to Material and Life science Facility (MLF) with 400 MeV injection energy was started from February 2014. Owing to the beam commissioning with 400 MeV injection energy, the amount of the beam loss was enough small and we established 300 kW continuous operation. In this paper, we report the present status and future plan of J-PARC linac and RCS.
