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Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.
Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12
Times Cited Count：6 Percentile：51.19(Geosciences, Multidisciplinary)The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.
Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Kawamata, Hiroshi*; Saito, Yoshio*; Baba, Hiroshi*
Proceedings of 25th International Linear Accelerator Conference (LINAC 2010) (CD-ROM), p.521 - 523, 2010/09
The fabrication of a new RFQ has been started as a backup machine for the J-PARC linac. The RFQ cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes, those are brazed together. A one-step vacuum brazing of a unit tank was adopted to unite these four vanes together with the flanges and ports. At the first tank brazing, the vacuum leak has been occurred due to the non-uniform temperature rise during the heating. Repair of this leakage and the results of the improved brazing of the second tank are reported.
Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Kawamata, Hiroshi*; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Saito, Yoshio*; Baba, Hiroshi*
Proceedings of 25th International Linear Accelerator Conference (LINAC 2010) (CD-ROM), p.518 - 520, 2010/09
The fabrication of a new RFQ has been started in the J-PARC linac. The RFQ cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes, those will be brazed together. To reduce the costs and periods to develop the special formed bite for the modulation machining, a numerical controlled machining using a conventional ball-end-mill was adopted for the vane modulation cutting instead of the wheel shape cutter. The dimension accuracy was confirmed by cutting test pieces. Moreover, the obtained surface seems smooth enough for the operation. Results of the ball-end-mill machining for the vanes are described.
Hasegawa, Kazuo; Kobayashi, Tetsuya; Kondo, Yasuhiro; Morishita, Takatoshi; Oguri, Hidetomo; Hori, Yoichiro*; Kubota, Chikashi*; Matsumoto, Hiroshi*; Naito, Fujio*; Yoshioka, Masakazu*
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.621 - 623, 2010/05
The J-PARC RFQ accelerates a negative hydrogen beam from 50 keV to 3 MeV. Beam commissioning of the J-PARC linac started in November 2006 and the linac has delivered beams to the 3 GeV synchrotron since September 2007. Trip rates of the RFQ, however, unexpectedly increased in September 2008. We tried to recover by tender conditioning, improvement of vacuum properties, etc. User operations for the Material and Life Experimental Facilities were successfully carried out at 20 kW in June 2009, and the beam power was increased to 120 kW in November. The high power operation at 300 kW for one hour was also demonstrated. Status and improvement of the J-PARC RFQ are presented.
Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Kawamata, Hiroshi*; Saito, Yoshio*; Baba, Hiroshi*
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.783 - 785, 2010/05
The J-PARC RFQ (length 3.1 m, 4-vane type, 324 MHz) accelerates a negative hydrogen beam from 0.05 MeV to 3 MeV toward the following DTL. The stability of the operating RFQ decreased for a few months at the end of 2008, then, we started a preparation of a new RFQ as a backup machine in the case of RFQ problem. The beam dynamics design of the new RFQ is the same as the current cavity for a quick resumption of operation, however, the engineering and RF designs are changed to improve stability. The processes of the vane machining and the surface treatments have been carefully considered to reduce the discharge problem. The vacuum brazing technique has been chosen for vane jointing. The design of the new RFQ and the fabrication progress is descried in this proceeding.
Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Hori, Yoichiro*; Kawamata, Hiroshi*; Saito, Yoshio*; Baba, Hiroshi*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1047 - 1049, 2010/03
The beam commissioning of J-PARC linac has been started since November 2006. After the scheduled shutdown in summer 2007, the beam is successfully delivered from the linac to the RCS. Since then, a stable beam provision was emphasized. However, the trip in the RFQ was increased at the end of Sept. 2008, then, the stability of the beam operation decreased. To improve this situation, we started to prepare a new RFQ cavity as a backup machine. The basic concept of the engineering design is the simplicity and the effective vacuum pumping aiming at the stable operation. A 3m long cavity is divided into 3 modules longitudinally. A numerical control machining with ball-end mill is chosen for a vane machining. Four vanes are vacuum brazed each other after machining. Each modules are aligned on the platform using a linear motion guide. A basic design of the key components on machining and brazing are described in this proceeding.
Morishita, Takatoshi; Kondo, Yasuhiro; Hasegawa, Kazuo; Naito, Fujio*; Matsumoto, Hiroshi*; Hori, Yoichiro*
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1050 - 1052, 2010/03
The beam commissioning of J-PARC linac has been started since November 2006. After the scheduled shutdown in summer 2007, the beam is successfully delivered from the linac to the RCS. Since then, a stable beam provision to RCS was emphasized. However, the trip in the RFQ was increased at the end of Sept. 2008, then, the stability of the beam operation decreased. To improve this situation, we started to prepare a new RFQ cavity as a backup machine. The RF simulation is underway for the design of this backup RFQ. A basic estimation on the key components on RF properties such as a tuner, a dipole stabilizer, and a local field correction at the vacuum port are described in this proceeding.
Hasegawa, Kazuo; Morishita, Takatoshi; Kondo, Yasuhiro; Oguri, Hidetomo; Kobayashi, Tetsuya; Naito, Fujio*; Yoshioka, Masakazu*; Matsumoto, Hiroshi*; Kawamata, Hiroshi*; Hori, Yoichiro*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.693 - 695, 2010/03
The J-PARC RFQ (length 3.1m, 4-vane type, 324 MHz) accelerates a beam from the ion source to the DTL. The beam test of the linac was started in November 2006 and 181 MeV beam was successfully accelerated in January 2007. Since then, the linac has been delivered beams for commissioning of the linac itself, downstream accelerators and facilities. Trip rates of the RFQ, however, suddenly increased in Autumn 2008, and we are suffering from this issue for user run operation. We tried to recover by tender conditioning, modification of RF control, improvement of vacuum and so on. We manage to have beam operation. In this report, we describe the status of the RFQ.
Futakawa, Masatoshi; Kogawa, Hiroyuki; Hasegawa, Shoichi; Naoe, Takashi; Ida, Masato; Haga, Katsuhiro; Wakui, Takashi; Tanaka, Nobuatsu*; Matsumoto, Yoichiro*; Ikeda, Yujiro
Journal of Nuclear Science and Technology, 45(10), p.1041 - 1048, 2008/10
Times Cited Count：32 Percentile：87.37(Nuclear Science & Technology)The life time of mercury target will be reduced by the cavitation damage induced by pressure waves. Micro-bubble injection into mercury is one of prospective technologies to mitigate the pressure waves. We have carried out damage tests using mercury loop with an impact generator to evaluate the bubbling effect on the pressure response and cavitation damage. The impulsive pressure was hardly changed but the damage was reduced remarkably by the micro-bubble injection. Numerical simulation was performed to investigate the bubbling effects. It was understandable that micro bubbles suppressed cavitation inception.
Futakawa, Masatoshi; Kogawa, Hiroyuki; Hasegawa, Shoichi; Ikeda, Yujiro; Riemer, B.*; Wendel, M.*; Haines, J.*; Bauer, G.*; Naoe, Takashi; Okita, Kohei*; et al.
Journal of Nuclear Materials, 377(1), p.182 - 188, 2008/06
Times Cited Count：28 Percentile：85.1(Materials Science, Multidisciplinary)no abstracts in English
Ida, Toshikazu*; Suyama, Kenya; Shimazu, Yoichiro*; *; Matsumoto, Hideki*; Shiraki, Takako*
Nihon Genshiryoku Gakkai-Shi, 42(9), p.903 - 906, 2000/09
no abstracts in English
Sato, Junya; Kuramochi, Ryo*; Shimizu, Koki; Matsumoto, Saori; Taniguchi, Takumi; Kuroki, Ryoichiro; Osugi, Takeshi
no journal, ,
no abstracts in English
