Design and actual performance of J-PARC 3 GeV rapid cycling synchrotron for high-intensity operation

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

https://doi.org/10.1080/00223131.2022.2038301

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.

A Failure investigation of the beam collimator system in the J-PARC 3 GeV rapid cycling synchrotron

Okabe, Kota; Yamamoto, Kazami; Kamiya, Junichiro; Takayanagi, Tomohiro; Yamamoto, Masanobu; Yoshimoto, Masahiro; Takeda, Osamu*; Horino, Koki*; Ueno, Tomoaki*; Yanagibashi, Toru*; et al.

Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.853 - 857, 2017/12

http://www.pasj.jp/web_publish/pasj2017/proceedings/PDF/WEP0/WEP021.pdf

The most important issue is to reduce the uncontrolled beam loss in the high intensity hadron accelerator such as J-PARC proton accelerators. The J-PARC 3 GeV Synchrotron (RCS) has a collimator system which narrows a high intensity beam in the RCS. After startup of RCS in 2007, the collimator system of the RCS worked well. However, in April 2016, vacuum leakage at the collimator system occurred during the maintenance operation. To investigate a cause of the failure, we took apart iron shields of the collimator reducing exposed dose of operators. As a result of inspection, we succeeded to identify the cause of the vacuum leakage failure. In this presentation, we report the failure investigation of the beam collimator system in the RCS.

Study on radionuclide analysis of rubble and plants for decommissioning of Fukushima Daiichi Nuclear Power Station

Seki, Kotaro; Sasaki, Takayuki*; Akimoto, Yuji*; Tokunaga, Takahito; Tanaka, Kiwamu; Haraga, Tomoko; Ueno, Takashi; Ishimori, Kenichiro; Hoshi, Akiko; Kameo, Yutaka

JAEA-Technology 2016-013, 37 Pages, 2016/07

JAEA-Technology-2016-013.pdf:2.09MB

In this study, based on the simple and rapid analytical method established from the wastes from research facilities, we created analytical schemes which is applicable to rubble and plants collected at Fukushima Daiichi, then transported to Nuclear Science Research Institute of JAEA. We examined the applicability, and confirmed quantifiability of radioactivity concentration with high recovery rate without being affected by fission products such as Sr and Cs.

New injection bump power supply of the J-PARC RCS

Takayanagi, Tomohiro; Ueno, Tomoaki*; Horino, Koki; Tobita, Norimitsu; Hayashi, Naoki; Kinsho, Michikazu; Irie, Yoshiro*; Okabe, Kota; Tani, Norio; Naito, Shingo*; et al.

Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1169 - 1174, 2015/09

http://www.pasj.jp/web_publish/pasj2015/proceedings/PDF/THP0/THP073.pdf

The new injection bump power supply for the shift bump magnet of the beam injection sub-systems at the J-PARC (Japan Proton Accelerator Research Complex) 3-GeV RCS (Rapid Cycling Synchrotron) has been developed and manufactured. The power capacity of the new power supply was more than doubled with the injection beam energy upgrading of the LINAC (Linear Accelerator) from 181 MeV to 400 MeV. Furthermore, the low ripple noise on the output current was required to prevent the resonance of the RF shield loop at the ceramic duct with the excitation magnetic field. The power supply newly adopted a capacitor commutation method to form the trapezoid waveform pattern (bump waveform). This paper reports characteristic about the new power supply.

Development and present status of new horizontal shift bump power supply for injection bump at the J-PARC RCS

Takayanagi, Tomohiro; Ueno, Tomoaki; Horino, Koki; Hayashi, Naoki; Kinsho, Michikazu; Okabe, Kota; Irie, Yoshiro*

Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1139 - 1142, 2014/10

http://www.pasj.jp/web_publish/pasj2014/proceedings/PDF/SUP0/SUP059.pdf

The new shift bump (SB) power supply which doubled power supply capacity has been developed and manufactured according to upgrading of 400MeV injection beam energy of the LINAC (Linear accelerator) in J-PARC (Japan Proton Accelerator Research Complex) 3-GeV RCS (Rapid-Cycling Synchrotron). The power supply adopted a capacitor commutation method to form the trapezoid waveform pattern (bump waveform) by the IGBT (Insulated Gate Bipolar Transistor) switch. The test operation was started in January, 2014. However, the trouble of a diode in the FT-unit (Flat top unit) was frequent and the user operation of the J-PARC was started without the FT-unit. As a result, the flat-top part of the bump waveform was became a downward, and it has been to a formation defectiveness wave pattern. Therefore, using a horizontal paint bump magnet and a pulse steering magnet, the beam injection point of the RCS was fixed. This paper will be reported the characteristic, the trouble and the user operation about the new shift bump power supply.

Efficiency testing of the control and cooling systems of JRR-2

Kambara, Toyozo; Shoda, Katsuhiko; Hirata, Yutaka; Shoji, Tsutomu; Haginoya, Kinichi; Kohayakawa, Toru; Yamaki, Jikei; Yokota, Mitsuo; Horiki, Oichiro; Yuhara, Shunichi; et al.

JAERI 1023, 120 Pages, 1962/09

JAERI-1023.pdf:8.67MB

no abstracts in English

Critical experiments and characteristic measurement for JRR-2

JRR-2 Critical Experiments Group; Kambara, Toyozo; Shoda, Katsuhiko; Hirata, Yutaka; Shoji, Tsutomu; Kohayakawa, Toru; Morozumi, Minoru; Kambayashi, Yuichiro; Shitomi, Hajimu; Kokanezawa, Takashi; et al.

JAERI 1025, 62 Pages, 1962/03

JAERI-1025.pdf:4.6MB

no abstracts in English

Troubleshooting of new injection shift-bump power supply of J-PARC RCS

Takayanagi, Tomohiro; Hayashi, Naoki; Kinsho, Michikazu; Ueno, Tomoaki*; Horino, Koki; Okabe, Kota; Irie, Yoshiro*

no journal, , 

New injection shift-bump (SB) power supply of the 3-GeV Rapid-Cycling Synchrotron (RCS) at Japan Proton Accelerator Research Complex (J-PARC) has been developed and manufactured. The power supply adopted a capacitor commutation method to form the trapezoid waveform pattern (bump waveform) at 32 kA peak by the Insulated Gate Bipolar transistor (IGBT) switch. However, in the test operation, the diodes of the DC charger for the capacitor in the Flat-top unit (Ft-unit) were frequently damaged. It is found the delay of the risetime for the current feedback loop is the cause of the overvoltage across the diodes. This paper reports the characteristic and troubleshooting of the SB power supply.

Injecting painting improvements in the J-PARC RCS

Kato, Shinichi; Harada, Hiroyuki; Hotchi, Hideaki; Saha, P. K.; Okabe, Kota; Takayanagi, Tomohiro; Horino, Koki; Ueno, Tomoaki; Tobita, Norimitsu*; Kinsho, Michikazu

no journal, , 

In the J-PARC 3GeV RCS, the injection painting is essential method for the reduction of the space charge force. In this method, the H beam from Linac is arranged on the large phase space area of the ring orbit during multiple turns. To implement this method, painting magnets form the time variable beam orbit. Therefore, the precise output current control of the magnet power supply is required. Because the power supply controlled by mainly feedforward signal is operated, we developed the iterative tuning method for the optimum feedforward parameter determination. As a result, we could reduce the tracking error of the current compared to before. Furthermore, to improve the accuracy of the painting area size, we applied the output readjustment additionally. Because the current monitor value of the power supply was different from the actual magnetic field due to the delay in the circuit and the leakage field, we corrected the tracking of the current based on the measured painting area size determined by the analysis of the measured COD. As a result, we achieved the precise injection painting. This talk presents these improvement results of the injection painting in the RCS.

Upgrading of RANS time-of-flight neutron diffraction measurement technique

Iwamoto, Chihiro*; Takamura, Masato*; Ueno, Kota*; Kurihara, Ryo*; Xu, P. G.; Suzuki, Hiroshi; Otake, Yoshie*

no journal, , 

no abstracts in English

Novel methodological study for neutron diffraction stress measurement using compact accelerator-driven neutron source RANS

Iwamoto, Chihiro*; Takamura, Masato*; Ueno, Kota*; Kataoka, Minami*; Kurihara, Ryo*; Xu, P. G.; Otake, Yoshie*

no journal, ,