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Shibata, Takanori*; Hirano, Koichiro; Hirane, Tatsuya*; Shinto, Katsuhiro; Hayashi, Naoki; Oguri, Hidetomo
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.417 - 421, 2021/10
In J-PARC linac, the operation of an rf-driven high-intensity H
ion source was initiated in 2014. For plasma ignition, the 2-MHz rf amplifier outputs the power of several tens kW. However the rf amplifier for the ion source and those for the accelerating cavities have not been synchronized. As a result, the wave hights in the beam waveforms were different in shot by shot. Therefore, we have developed an synchronization system between the rf system for the ion source and those for the cavity systems and succeeded the same wave hights in the waveforms.
Fuwa, Yasuhiro; Shinozaki, Shinichi; Chishiro, Etsuji; Hirane, Tatsuya; Fang, Z.*; Fukui, Yuji*; Futatsukawa, Kenta*; Mizobata, Satoshi*; Iwama, Yuhei*; Sato, Yoshikatsu*; et al.
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.611 - 613, 2019/10
In the J-PARC linac, a proton accelerator is operated using 45 units of 324 MHz and 972 MHz klystrons. In the future stabilization and advancement of the accelerator, it is important to acquire the klystron output characteristics near the maximum output accurately. In order to understand this characteristics, measurement of the characteristics of the replaced klystron for some reason such as discharge, as well as the new klystron. However, such measurements have not been performed because of the risk of damage including peripheral equipment due to discharge and the temporal interference with the operation of the accelerator. Therefore, we set up a klystron test stand in the linac building and measured the high-voltage characteristics and input/output characteristics of the klystron under various operating parameters. By using this measurement result, the characteristics of klystron can be obtained before installation, and it becomes possible to determine the optimum operation parameters and make effective plan of klystron replacements. In addition, basic data for predicting the degradation tendency of klystron was acquired by comparing the characteristics of the used and used klystron.
Chishiro, Etsuji; Sagawa, Ryu*; Toriyama, Minoru*
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.400 - 402, 2016/11
Klystron power supplies in the J-PARC have been generated high voltage DC power by chopping 12-phase AC voltage power by thyristors, and boosting the voltage up to 110 kV in step-up transformer and rectifying the voltage in high voltage rectifiers. Some of the high voltage transformers (HVTR), which consist of the step-up transformer and the high voltage rectifier and the reactor, were often broken in the running time of over 30,000 hours. This failure caused the long-term shut down of the J-PARC facility. The high voltage rectifier composed diodes and condensers by a series connection of 66 stages. Investigation of the failed rectifier shows that the capacitors ware applied the overvoltage because the flashover occurred on the ceramic surface. We investigated the mechanisms applying the overvoltage and took measure for the overvoltage to the rectifier. The HVTR with the improved rectifier has been operating for long term to assess the modification effect.
Chishiro, Etsuji; Kawamura, Masato*; Sagawa, Ryu*; Ogawa, Shinichi*
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1091 - 1093, 2014/10
In J-PARC linac, six units of high voltage power supplies for 324 MHz klystrons have operated since 2006, and those running time exceed 35,000 hours. In addition, six units of power supplies for the 972 MHz klystrons have been operation since 2013. In the power supply, various troubles occur under the operation. In some anode modulators, arc discharge in the transformer oil had occurred due to the deterioration of the auxiliary solid insulator. In three modules combining a step-up transformer and a rectifier, the high voltage diode was breakdown because an unexpected overvoltage was applied. And by improving the voltage dividing resistor of the module, high stability cathode voltage was achieved. In this report, we describe the trouble and the improvement that occurred in the equipment.
Chishiro, Etsuji; Hori, Toshihiko*; Kobayashi, Tetsuya; Suzuki, Hiroyuki*; Suganuma, Kazuaki; Yamazaki, Masayoshi*; Anami, Shozo*; Fang, Z.*; Fukuda, Shigeki*; Fukui, Yuji*; et al.
Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.236 - 238, 2005/07
no abstracts in English
Kobayashi, Tetsuya; Chishiro, Etsuji; Anami, Shozo*; Yamaguchi, Seiya*; Michizono, Shinichiro*
Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.320 - 322, 2004/08
J-PARC (Japan Proton Accelerator Complex) linac, which is 300 m long, consists of 324 MHz accelerating section of the upstream and 972 MHz section (as future plan) of the downstream. In the klystron gallery, totally about 60 RF source control stations will stand for the klystrons and solid-state amplifiers. The error of the accelerating field must be within 
1 degree in phase and 1% in amplitude. Thus, the high phase stability is required to the RF reference for all of the low-level RF control systems and the beam monitor systems. This paper presents a final design and the summary of the performance evaluation of the RF reference distribution system including the timing control signal distribution for this linac.
Kobayashi, Tetsuya; Suzuki, Hiroyuki*; Anami, Shozo*; Yamaguchi, Seiya*; Kawamura, Masato*; Fukui, Yuji*; Kadokura, Eiichi*; Kamikubota, Norihiko*; Takagi, Makoto*; Yoshida, Susumu*; et al.
Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.314 - 316, 2004/08
The beam study of the low-energy front of J-PARC linac has been in progress in the KEK site. Last year, DTL1 (the first tank of three DTL's) was installed in addition to RFQ and the Medium Energy Beam Transport line, and the beam commissioning up to 20MeV has been performed successfully. In this paper, the low level RF (LLRF) System for this beam test is summarized and the performance of the RF feed back control system and monitor system of the phase and amplitude of the accelerating fields (324 MHz) is presented. It was found that the feed back system for Bunchers is also necessary to stabilize and to compensate for the beam induced fields.
Hasegawa, Kazuo; High-intensity Proton Accelerator Linac Group
Proceedings of 28th Linear Accelerator Meeting in Japan, p.66 - 68, 2003/08
no abstracts in English
Tezuka, Katsuhiko*; Miyake, Setsuo*; Sakamoto, Mitsunori*; Chishiro, Etsuji; Fukuda, Shigeki*; Kawamura, Masato*; Anami, Shozo*
Proceedings of 28th Linear Accelerator Meeting in Japan, p.372 - 374, 2003/07
no abstracts in English
Kawamura, Masato*; Anami, Shozo*; Fukui, Yuji*; Kubota, Chikashi*; Ono, Masaaki*; Chishiro, Etsuji; Yumino, Yuichi*; Kubo, Hiroshi*
Proceedings of 28th Linear Accelerator Meeting in Japan, p.369 - 371, 2003/07
no abstracts in English
Chishiro, Etsuji*; Touchi, Y.*; Kaneko, H.*; Kusano, Joichi; Hasegawa, Kazuo; Mizumoto, Motoharu
Proc. of 1st Asian Particle Accelerator Conf. (APAC98), p.83 - 85, 1998/00
no abstracts in English
Chishiro, Etsuji*; Takado, H.*; Touchi, Y.*; Kusano, Joichi; Mizumoto, Motoharu
Proceedings of 23rd Linear Accelerator Meeting in Japan, p.243 - 245, 1998/00
no abstracts in English
Moriyama, Shinichi; Fujii, Tsuneyuki; Kimura, Haruyuki; Saigusa, Mikio; Yamamoto, Takumi; Maebara, Sunao; *; *; *
Fusion Technology 1994, 0, p.549 - 552, 1995/00
no abstracts in English
