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Shobuda, Yoshihiro; Harada, Hiroyuki; Saha, P. K.; Takayanagi, Tomohiro; Tamura, Fumihiko; Togashi, Tomohito; Watanabe, Yasuhiro; Yamamoto, Kazami; Yamamoto, Masanobu
Physical Review Accelerators and Beams (Internet), 26(5), p.053501_1 - 053501_45, 2023/05
Times Cited Count:0 Percentile:0.02(Physics, Nuclear)At the Rapid Cycling Synchrotron (RCS) in Japan Proton Accelerator Research Complex (J-PARC), theoretical predictions have indicated that the kicker-impedance would excite the beam-instability. A 1 MW beam with large emittance can be delivered to the Material and Life Science Experimental Facility (MLF) through suppression of the beam instabilities by choosing the appropriate machine parameters. However, we require other high-intensity and high-quality smaller emittance beams (than the 1 MW beam) for the Main Ring (MR). Hence, we proposed a scheme for suppressing the kicker-impedance by using prototype diodes and resistors, thereby demonstrating the effect on the kicker impedance reduction. However, the J-PARC RCS must be operated with a repetition rate of 25 Hz, which urged us to consider special diodes that are tolerant to heating. After developments, we have demonstrated that the special diodes with resistors can suppress the beam instability by reducing the kicker impedance. Enhanced durability of the prototype diodes and resistors for the 25 Hz operation was also realized. Moreover, the new diodes and the resistors have negligible effect on the extracted beam from the RCS. From a simulation point of view, the scheme can be employed for at least 5 MW beam operation within the stipulated specifications.
Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
Times Cited Count:3 Percentile:80.29(Nuclear Science & Technology)In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.
Shobuda, Yoshihiro; Irie, Yoshiro*; Takayanagi, Tomohiro; Togashi, Tomohito; Yamamoto, Masanobu; Yamamoto, Kazami
Journal of Physics; Conference Series, 1067, p.062007_1 - 062007_8, 2018/10
Times Cited Count:2 Percentile:68.57The present four-terminal kicker at the Rapid Cycling Synchrotron (RCS) at the Japan Proton Accelerator Research Complex (J-PARC) has the power-saving benefit due to the doubled excitation currents by shorting two-terminals. On the other hand, beam instabilities are excited by the kicker impedances. In this report, we describe a scheme to reduce the kicker impedances using diodes (nonlinear devices) with resistors, while retaining the benefit of the doubled kicker excitation currents.
Shobuda, Yoshihiro; Chin, Y. H.*; Hayashi, Naoki; Irie, Yoshiro*; Takayanagi, Tomohiro; Togashi, Tomohito; Toyama, Takeshi*; Yamamoto, Kazami; Yamamoto, Masanobu
Physical Review Accelerators and Beams (Internet), 21(6), p.061003_1 - 161003_15, 2018/06
Times Cited Count:4 Percentile:36.63(Physics, Nuclear)no abstracts in English
Shobuda, Yoshihiro; Saha, P. K.; Hotchi, Hideaki; Harada, Hiroyuki; Takayanagi, Tomohiro; Tamura, Fumihiko; Tani, Norio; Togashi, Tomohito; Toyama, Takeshi*; Watanabe, Yasuhiro; et al.
Proceedings of 8th International Particle Accelerator Conference (IPAC '17) (Internet), p.2946 - 2949, 2017/05
no abstracts in English
Hayashi, Naoki; Harada, Hiroyuki; Horino, Koki; Hotchi, Hideaki; Kamiya, Junichiro; Kinsho, Michikazu; Saha, P. K.; Shobuda, Yoshihiro; Takayanagi, Tomohiro; Tani, Norio; et al.
Proceedings of 4th International Particle Accelerator Conference (IPAC '13) (Internet), p.3833 - 3835, 2014/07
no abstracts in English
Watanabe, Masao; Hayashi, Naoki; Shobuda, Yoshihiro; Suganuma, Kazuaki; Takayanagi, Tomohiro; Togashi, Tomohito; Toyama, Takeshi*
Proceedings of 3rd International Particle Accelerator Conference (IPAC '12) (Internet), p.3629 - 3631, 2012/05
Stable operation is required for RCS at J-PARC. In the kicker system at extraction section of RCS, there had been many troubles for unstable operation of the thyratrons switches of the power supply just after 25 pps operation started in February 2009. However, the operation was improved by handling thyratrons in appropriate manner in October 2010. After the grate earthquake on 11 March 2011, injection and extraction magnets, power supplies, cables and bus-duct were checked. The results of the measurements and the checks were all not in the problem. We have to reach extraction beam power of 1 MW in RCS in the near future. Kicker impedance is most severe among other impedance sources. The matching resistor and newly developed diodes are connected at the power supply to reduce the impedance. We confirmed that reduced voltages and stable operation of accelerator.
Haga, Takahisa*; Gunji, Kazuhiko; Fukaya, Hiroyuki; Sonoda, Takashi; Sakazume, Yoshinori; Sakai, Yutaka; Niitsuma, Yasushi; Togashi, Yoshihiro; Miyauchi, Masakatsu; Sato, Takeshi; et al.
JAERI-Tech 2004-005, 54 Pages, 2004/02
Criticality experiments using uranyl nitrate solution fuel are being conducted at STACY (the Static Experiment Critical Facility) and TRACY (the Transient Experiment Critical Facility) in NUCEF (the Nuclear Fuel Cycle Safety Engineering Research Facility). Chemical analyses of the solution have been carried out to take necessary data for criticality experiments, for treatment and control of the fuel, and for safeguards purpose at the analytical laboratory placed in NUCEF. About 300 samples are analyzed annually that provide various kinds of data, such as uranium concentration, isolation acid concentration, uranium isotopic composition, concentration of fission product (FP) nuclides, tri-butyl phosphoric acid (TBP) concentration, impurities in the solution fuel and so on. This report summarizes the analytical methods and quality management of the analysis for uranyl nitrate solution relating to the criticality experiments.
Uchiyama, Gunzo; Watanabe, Kazuo; Miyauchi, Masakatsu; Togashi, Yoshihiro; Nakahara, Yoshinori; Fukaya, Hiroyuki; Inagawa, Jun; Suzuki, Daisuke; Sonoda, Takashi; Kono, Nobuaki; et al.
Journal of Radiation Research, 42(Suppl.), p.S11 - S16, 2001/10
no abstracts in English
Togashi, Yoshihiro; Miyauchi, Masakatsu; Sonobe, Tamotsu; Niitsuma, Yasushi; Nakajima, Takayuki; Haga, Takahisa*; Tanoue, Takahiro; Fukaya, Hiroyuki; Sonoda, Takashi; Sakazume, Yoshinori; et al.
JAERI-Tech 2000-032, p.25 - 0, 2000/03
no abstracts in English
Fujine, Sachio; Murata, Mikio; Abe, Hitoshi; Takada, Junichi; Tsukamoto, Michio; Miyata, Teijiro*; Ida, Masaaki*; Watanabe, Makio; Uchiyama, Gunzo; Asakura, Toshihide; et al.
JAERI-Research 99-056, p.278 - 0, 1999/09
no abstracts in English
Sonoda, Takashi; Togashi, Yoshihiro; Miyauchi, Masakatsu; Okazaki, Shuji*
JAERI-Tech 99-043, 16 Pages, 1999/05
no abstracts in English
Togashi, Yoshihiro; *; *
IMechE Conf. Trans., Int. Conf. on Nuclear Decommissioning, 0, p.29 - 39, 1995/00
no abstracts in English
; Kanazawa, Hiroyuki; Togashi, Yoshihiro; ; Nishino, Yasuharu; ; Nakata, Masahito; Amano, Hidetoshi;
JAERI-Research 94-008, 20 Pages, 1994/08
no abstracts in English
; ; M.W.A.Stewart*; Tsuboi, Takashi; *; E.R.Vance*; K.P.Hart*; Togashi, Yoshihiro; Kanazawa, Hiroyuki; C.J.Ball*; et al.
Journal of the American Ceramic Society, 77(9), p.2255 - 2264, 1994/00
Times Cited Count:30 Percentile:80.45(Materials Science, Ceramics)no abstracts in English
Togashi, Yoshihiro;
JAERI-M 93-077, 12 Pages, 1993/03
no abstracts in English
; ; K.P.Hart*; *; E.R.Vance*; Tamura, Yukito; Togashi, Yoshihiro; White, T. J.*
Journal of the American Ceramic Society, 75(2), p.392 - 400, 1992/02
Times Cited Count:25 Percentile:76.01(Materials Science, Ceramics)no abstracts in English
Togashi, Yoshihiro; *;
JAERI-M 91-177, 9 Pages, 1991/11
no abstracts in English
; ; *; White, T. J.*; *; Togashi, Yoshihiro; ; ; D.M.Levins*;
Journal of the American Ceramic Society, 73(11), p.3433 - 3441, 1990/11
Times Cited Count:10 Percentile:56.08(Materials Science, Ceramics)no abstracts in English
; Togashi, Yoshihiro; ; *; Tamura, Yukito;
Applied Radiation and Isotopes, 41(9), p.839 - 845, 1990/09
no abstracts in English