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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.
Kamiya, Junichiro; Nii, Keisuke*; Kabumoto, Hiroshi; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; Matsuda, Makoto; Moriya, Katsuhiro; Ida, Yoshiaki*; et al.
e-Journal of Surface Science and Nanotechnology (Internet), 21(4), p.344 - 349, 2023/05
no abstracts in English
Saha, P. K.; Okabe, Kota; Nakanoya, Takamitsu; Shobuda, Yoshihiro; Harada, Hiroyuki; Tamura, Fumihiko; Okita, Hidefumi; Yoshimoto, Masahiro; Hotchi, Hideaki*
Journal of Physics; Conference Series, 2420, p.012040_1 - 012040_7, 2023/01
Nii, Keisuke*; Ida, Yoshiaki*; Ueda, Hideki*; Yamaguchi, Takanori*; Kabumoto, Hiroshi; Kamiya, Junichiro; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; et al.
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.601 - 604, 2023/01
no abstracts in English
Saha, P. K.; Okabe, Kota; Nakanoya, Takamitsu; Yoshimoto, Masahiro; Shobuda, Yoshihiro; Harada, Hiroyuki; Tamura, Fumihiko; Okita, Hidefumi; Hatakeyama, Shuichiro; Moriya, Katsuhiro; et al.
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1 - 5, 2023/01
Fujita, Manami; Hasegawa, Shoichi; Hosomi, Kenji; Ichikawa, Masaya; Ichikawa, Yudai; Kim, S.; Nanamura, Takuya; Sako, Hiroyuki; Tamura, Hirokazu; Yamamoto, Takeshi; et al.
Progress of Theoretical and Experimental Physics (Internet), 2022(12), p.123D01_1 - 123D01_17, 2022/12
Times Cited Count:0 Percentile:0.01(Physics, Multidisciplinary)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:6 Percentile:84.97(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.
Nanamura, Takuya; Fujita, Manami; Hasegawa, Shoichi; Ichikawa, Masaya; Ichikawa, Yudai; Imai, Kenichi*; Naruki, Megumi; Sato, Susumu; Sako, Hiroyuki; Tamura, Hirokazu; et al.
Progress of Theoretical and Experimental Physics (Internet), 2022(9), p.093D01_1 - 093D01_35, 2022/09
Times Cited Count:5 Percentile:67.44(Physics, Multidisciplinary)Kakimoto, Kazuo*; Takada, Saki*; Ota, Hiroto*; Hayaguchi, Yuya*; Hagihara, Masato; Torii, Shuki*; Kamiyama, Takashi*; Mitamura, Hiroyuki*; Tokunaga, Masashi*; Hatakeyama, Atsushi*; et al.
Journal of the Physical Society of Japan, 91(5), p.054704_1 - 054704_7, 2022/05
Times Cited Count:1 Percentile:28(Physics, Multidisciplinary)Asakura, Kazuki; Shimomura, Yusuke; Donomae, Yasushi; Abe, Kazuyuki; Kitamura, Ryoichi; Miyakoshi, Hiroyuki; Takamatsu, Misao; Sakamoto, Naoki; Isozaki, Ryosuke; Onishi, Takashi; et al.
JAEA-Review 2021-020, 42 Pages, 2021/10
The disposal of radioactive waste from the research facility need to calculate from the radioactivity concentration that based on variously nuclear fuels and materials. In Japan Atomic Energy Agency Oarai Research and Development Institute, the study on considering disposal is being advanced among the facilities which generate radioactive waste as well as the facilities which process radioactive waste. This report summarizes a study result in FY2020 about the evaluation method to determine the radioactivity concentration in radioactive waste on Oarai Research and Development Institute.
Miwa, Koji*; Fujita, Manami; Hasegawa, Shoichi; Hosomi, Kenji; Ichikawa, Yudai; Imai, Kenichi*; Nanamura, Takuya; Naruki, Megumi; Sako, Hiroyuki; Sato, Susumu; et al.
Physical Review C, 104(4), p.045204_1 - 045204_20, 2021/10
Times Cited Count:12 Percentile:89.15(Physics, Nuclear)Nii, Keisuke*; Ida, Yoshiaki*; Ueda, Hideki*; Yamaguchi, Takanori*; Kabumoto, Hiroshi; Kamiya, Junichiro; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; et al.
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.334 - 337, 2021/10
no abstracts in English
Saha, P. K.; Yoshimoto, Masahiro; Okabe, Kota; Harada, Hiroyuki; Tamura, Fumihiko; Hotchi, Hideaki*
Proceedings of 12th International Particle Accelerator Conference (IPAC 21) (Internet), p.590 - 593, 2021/08
Yoshimoto, Masahiro*; Fujita, Manami; Hashimoto, Tadashi; Hayakawa, Shuhei; Ichikawa, Yudai; Ichikawa, Masaya; Imai, Kenichi*; Nanamura, Takuya; Naruki, Megumi; Sako, Hiroyuki; et al.
Progress of Theoretical and Experimental Physics (Internet), 2021(7), p.073D02_1 - 073D02_19, 2021/07
Times Cited Count:13 Percentile:81.3(Physics, Multidisciplinary)Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Kinsho, Michikazu; Okabe, Kota; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Kazami; Yamamoto, Masanobu; et al.
JPS Conference Proceedings (Internet), 33, p.011018_1 - 011018_6, 2021/03
no abstracts in English
Tamura, Fumihiko; Yamamoto, Masanobu; Yoshii, Masahito*; Sugiyama, Yasuyuki*; Hotchi, Hideaki; Saha, P. K.; Yoshimoto, Masahiro; Harada, Hiroyuki
JPS Conference Proceedings (Internet), 33, p.011021_1 - 011021_6, 2021/03
Chopped beam injection is employed in the J-PARC RCS to avoid the longitudinal beam losses. A fast beam chopper is installed in the MEBT section of the linac. The chopper is driven by the gate pulses sent from the LLRF control system of the RCS. The delay from the zero crossing of the RCS rf and the width are set so that the beam pulse is injected into the proper phase position of the rf bucket. A unique feature of the J-PARC chopper gate pulse generation is thinning of the pulses. The thinning is useful to control the beam intensity without changing much the condition of the longitudinal painting. Also, the beam macro pulse can be trimmed down to a single intermediate pulse by setting the parameters. In this poster, we present the overview of the generation of the chopper gate pulse in the LLRF control system and various beam commissioning results utilizing the flexibility of it. Also, we discuss the upgrade of the chopper gate pulse generation.
Yoshida, Junya; Akaishi, Takaya; Fujita, Manami; Hasegawa, Shoichi; Hashimoto, Tadashi; Hosomi, Kenji; Ichikawa, Masaya; Ichikawa, Yudai; Imai, Kenichi*; Kim, S.; et al.
JPS Conference Proceedings (Internet), 33, p.011112_1 - 011112_8, 2021/03
Sakao, Tamao*; Fujita, Manami; Hasegawa, Shoichi; Hosomi, Kenji; Ichikawa, Masaya; Ichikawa, Yudai; Imai, Kenichi*; Nanamura, Takuya; Naruki, Megumi; Sako, Hiroyuki; et al.
JPS Conference Proceedings (Internet), 33, p.011133_1 - 011133_6, 2021/03
Hayakawa, Shuhei; Fujita, Manami; Hasegawa, Shoichi; Hashimoto, Tadashi; Hosomi, Kenji; Ichikawa, Yudai; Imai, Kenichi*; Nanamura, Takuya; Naruki, Megumi; Sako, Hiroyuki; et al.
Physical Review Letters, 126(6), p.062501_1 - 062501_6, 2021/02
Times Cited Count:34 Percentile:95.34(Physics, Multidisciplinary)Gogami, Toshiyuki*; Fujita, Manami; Hasegawa, Shoichi; Hosomi, Kenji; Imai, Kenichi*; Ichikawa, Yudai; Nanamura, Takuya; Naruki, Megumi; Sako, Hiroyuki; Sato, Susumu; et al.
Journal of Physics; Conference Series, 1643, p.012133_1 - 012133_6, 2020/12
Times Cited Count:2 Percentile:84.57(Astronomy & Astrophysics)