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particles generated by residual gas stripping in the Japan Proton Accelerator Research Complex linacTamura, Jun; Futatsukawa, Kenta*; Kondo, Yasuhiro; Liu, Y.*; Miyao, Tomoaki*; Morishita, Takatoshi; Nemoto, Yasuo*; Okabe, Kota; Yoshimoto, Masahiro
Nuclear Instruments and Methods in Physics Research A, 1049, p.168033_1 - 168033_7, 2023/04
Times Cited Count：1 Percentile：68.31(Instruments & Instrumentation)The Japan Proton Accelerator Research Complex (J-PARC) linac is a high-intensity accelerator in which beam loss is a critical issue. In the J-PARC linac, H
beams are accelerated to 191~MeV by a separated drift tube linac (SDTL) and subsequently to 400~MeV by an annular-ring coupled structure (ACS). Because there are more beam loss mechanisms in H linacs than in proton linacs, it is imperative to investigate the beam loss circumstances for beam loss mitigation. Electron-stripping phenomena, which generate uncontrollable H particles, are characteristic beam loss factors of H linacs. To clarify the beam loss causes in the J-PARC linac, a new diagnostic line was installed in the beam transport between the SDTL and ACS. In this diagnostic line, H particles were separated from the H beam, and the intensity profiles of the H particles were successfully measured by horizontally scanning a graphite plate in the range where H particles were distributed. By examining the intensity variation of the H particles with different residual pressure levels, we proved that half of the H particles in the SDTL section are generated by the residual gas stripping in the nominal beam operation of the J-PARC linac.
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
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：5 Percentile：87.42(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.
Yamamoto, Kazami; Hatakeyama, Shuichiro; Otsu, Satoru*; Matsumoto, Tetsuro*; Yoshimoto, Masahiro
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.494 - 498, 2021/10
J-PARC 3 GeV Rapid Cycling Synchrotron (RCS) provides more than 700 kW proton beam to the neutron target. In order to investigate the influence of the radiation, we intend to evaluate the radiations such as the neutron and gamma-rays, which are generated due to the proton beam loss. If the amount of beam loss is excessive, it becomes difficult to identify the individual neutron and gamma ray. Therefore, we investigated the signal rate of the extraction point of RCS. Preliminary result indicated that we can enough distinguish the neutron and gamma-ray by the liquid scintillator.
Yamamoto, Kazami
EPJ Web of Conferences, 153, p.07022_1 - 07022_6, 2017/09
Times Cited Count：1 Percentile：61.03(Nuclear Science & Technology)The J-PARC 3 GeV Rapid Cycling Synchrotron (RCS) delivers a 1-MW, high-intensity beam to the following facilities. In such high-intensity accelerator, the operational beam intensity is limited to keep the exposure to the workers by the residual dose within acceptable tolerances. Therefore we continue to commission the accelerator system to reduce the beam loss. In order to achieve further high-intensity operation, the J-PARC accelerator system was drastically upgraded (Increment of the injection energy of RCS and peak current of Linac) over the past two years. After the upgrade, the beam loss was decreased by the commissioning. The output power was increased; nevertheless the residual doses were kept same level or decreased. Since we replaced the broken collimator which was higher activated, we kept the exposure to the workers within acceptable level.
Hotchi, Hideaki; Harada, Hiroyuki; Kato, Shinichi; Kinsho, Michikazu; Okabe, Kota; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Tani, Norio; Watanabe, Yasuhiro; et al.
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.61 - 65, 2016/11
After the RF power supply upgrade, the J-PARC 3-GeV RCS restarted a 1-MW beam test in October 2015. In the beam test in October, we successfully removed longitudinal beam loss by beam loading compensation as well as minimized space-charge induced beam loss by injection painting. In addition, in this beam test, beam instability was also well suppressed by controlling the tune and the chromaticity. Furthermore, in the following beam test, the transverse painting area was successfully expanded by introducing both quadrupole correctors and anti-correlated painting scheme, by which a foil scattering part of beam loss during charge-exchange injection was further reduced. By these recent efforts, the 1-MW beam operation is now estimated to be established within a permissible beam loss level. This paper presents recent progresses of 1-MW beam tuning with particular emphasis on our approaches to beam loss issues.
Sakamoto, Shinichi; Meigo, Shinichiro; Fujimori, Hiroshi*; Harada, Masahide; Konno, Chikara; Kasugai, Yoshimi; Kai, Tetsuya; Miyake, Yasuhiro*; Ikeda, Yujiro
Nuclear Instruments and Methods in Physics Research A, 562(2), p.638 - 641, 2006/06
Times Cited Count：8 Percentile：50.27(Instruments & Instrumentation)Materials and Life Science Facility of Japan Proton Accelerator Research Complex (J-PARC) is an experimental facility where neutron and muon beams are provided as powerful probes. They are generated with high-intensity proton beam supplied through a 3-GeV proton beam transport (3NBT) line. Its beam optics and components were designed to transport the proton beam of large emittance with extremely low loss rate. The 3NBT accommodates an intermediate target that causes large beam loss. The scheme of the cascade target system was carefully devised to overcome difficulties due to high radiation.
Kinsho, Michikazu
AIP Conference Proceedings 773, p.45 - 49, 2005/06
JAERI and KEK have been working on the J-PARC project for a high intensity proton accelerator. The accelerator complex consists of a 400MeV linac, a 3GeV rapid cycle synchrotron, and a 50GeV synchrotron ring. The major requirements for the accelerator are summarized as follows, (1) The accelerator should provide the 1MW beam with a repetition rate of 25 Hz and a pulse length less than 1 us to the full use of pulsed spallation neutrons. (2) It should provide the several ten GeV beams with a beam power of 0.75MW for nuclear and particle physics experiments. As for the design of such a high intensity proton accelerator, from the experience of the past accelerator operation, the average beam loss should be kept at an order of 1W/m with a view to hands-on maintenance. Accordingly, there are several kinds of beam collimator in each accelerator and beam transport lines to minimize and localize the beam loss. We reported mainly the design concept and simulation results of the beam loss for each section.
Sugimoto, Masayoshi
Proc. of 2nd Int. Topical Meeting on Nuclear Applications of Accelerator Technology (AccApp'98), p.566 - 571, 1998/00
no abstracts in English
Minehara, Eisuke; *; Sugimoto, Masayoshi; Sawamura, Masaru; Nagai, Ryoji; Kikuzawa, Nobuhiro; Nishimori, Nobuyuki
Proc. of 11th Symp. on Accelerator Sci. and Technol., p.444 - 445, 1997/00
no abstracts in English
; ; Kobayashi, Yasuhiko; ; Watanabe, Hiroshi
JAERI TIARA Annual Report, Vol. 1, 0, p.159 - 162, 1992/00
no abstracts in English
Nakamura, Yoshiteru; Arakawa, Kazuo; Mizuhashi, Kiyoshi; Yokota, Wataru; Kamiya, Tomihiro; Fukuda, Mitsuhiro; Nara, Takayuki; Agematsu, Takashi; Okumura, Susumu; Ishibori, Ikuo; et al.
Proc. of the 8th Symp. on Accelerator Science and Technology, p.194 - 196, 1991/00
no abstracts in English
; ; Abe, Shinichi; ; ; Horie, Katsuzo; Hanashima, Susumu
Review of Scientific Instruments, 58(2), p.215 - 219, 1987/02
Times Cited Count：1 Percentile：38.08(Instruments & Instrumentation)no abstracts in English
; ; Araki, Masanori; ; ; ; ; ; Matsuda, Shinzaburo; ; et al.
Review of Scientific Instruments, 55(3), p.332 - 337, 1984/00
Times Cited Count：19 Percentile：86.94(Instruments & Instrumentation)no abstracts in English
; Araki, Masanori; ; ; ; ; ; Matsuda, Shinzaburo; ; *; et al.
Review of Scientific Instruments, 53(12), p.1864 - 1869, 1982/00
Times Cited Count：20 Percentile：87.85(Instruments & Instrumentation)no abstracts in English
