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Nakanoya, Takamitsu; Yoshimoto, Masahiro; Saha, P. K.; Takeda, Osamu*; Saeki, Riuji*; Muto, Masayoshi*
Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.937 - 941, 2023/11
In the J-PARC 3GeV Rapid Cycling Synchrotron (RCS), the 400MeV H
beam is changed to H+ beam by a charge exchange foil and accelerated to 3GeV. So far, RCS had used two types of charge exchange foil. One is the HBC (Hybrid Boron mixed Carbon) foil and the other is the Kaneka GTF (Graphene Thin Film). HBC foil is a patented deposition method developed at KEK for the stable production of thick carbon foil. Initially, the RCS used HBC foil produced atKEK. However, in 2017, JAEA had started HBC foil production and has been using it since then. Recently, we have succeeded in depositing thick pure carbon foil, which had been considered difficult to produce by the arc deposition method. As a new challenge, this pure carbon foil was used in the user operation from March 2023. As a result, Pure carbon foils showed less deformation and more stable charge exchange performance than HBC and GTF.
Nakanoya, Takamitsu; Yoshimoto, Masahiro; Saha, P. K.; Takeda, Osamu*; Saeki, Riuji*; Muto, Masayoshi*
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.629 - 633, 2023/01
In the J-PARC 3-GeV Rapid Cycling Synchrotron (RCS), a 400 MeV H- beam injected from the linac is exchange to an H+ beam by a charge exchange foil and accelerated to 3 GeV. The charge exchange foils mainly used in the RCS are HBC foil (Hybrid Boron mixed Carbon stripper foil), which are made by adding a small amount of boron to carbon rods and using them as electrodes by the arc deposition method. Since 2018, foils produced by JAEA have been used for user operation. So far, no major problems have occurred due to the foils. Meanwhile, the beam power of the RCS has been gradually increased from 500 kW to 830 kW since 2018. As beam power increases, the foil issues were identified to achieve the RCS design power of 1 MW. In this paper, we will report on the recent foil usage status and issue in the user operation.
Autsavapromporn, N.*; Suzuki, Masao*; Funayama, Tomoo; Usami, Noriko*; Plante, I.*; Yokota, Yuichiro; Muto, Yasuko*; Ikeda, Hiroko; Kobayashi, Katsumi*; Kobayashi, Yasuhiko; et al.
Radiation Research, 180(4), p.367 - 375, 2013/10
Times Cited Count：58 Percentile：89.5(Biology)We investigated the role of gapjunction intercellular communication (GJIC) in the propagation of stressful effects in confluent normal human fibroblast cultures wherein only 0.036-0.144% of cells in the population were traversed by primary radiation tracks. Confluent cells were exposed to graded doses from X ray, carbon ion, neon ion or argon ion microbeams in the presence or absence of an inhibitor of GJIC. After 4 h incubation, the cells were assayed for micronucleus (MN) formation. Micronuclei were induced in a greater fraction of cells than expected based on the fraction of cells targeted by primary radiation, and the effect occurred in a dose-dependent manner with any of the radiation sources. Interestingly, the inhibition of GJIC depressed the enhancement of MN formation in bystander cells from cultures exposed to high-LET radiation but not low-LET radiation. The results highlight the important role of radiation quality and dose in the observed effects.
Muto, K.; Koakutsu, Masayuki; Nakazawa, Osamu; Hayafune, Hiroki; Kato, Hiroshi
Saikuru Kiko Giho, (24), 71 Pages, 2004/00
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
