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Sakashita, Koichi; Arakawa, Yuto; Masuyama, Koichi; Sato, Koichi; Seki, Kazunari; Kasugai, Yoshimi; Ishii, Tetsuro
Radiation Safety Management, 23, p.7 - 15, 2025/03
Yamamoto, Kazami; Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Kinsho, Michikazu; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Yoshimoto, Masahiro; Nakane, Yoshihiro; et al.
Progress in Nuclear Science and Technology (Internet), 4, p.238 - 242, 2014/04
A 3 GeV rapid cycling synchrotron (RCS) at J-PARC was commissioned in October 2007. Afterwards, the beam intensity was increased through a beam study, and the RCS has continuously provided a proton beam 
100 kW to the neutron target since October 2009. With renewed efforts brought about by beam commissioning, we have reduced losses in the RCS and achieved low-loss operation. We present the history of the operational beam power and the residual dose distributions after operation.
Murata, Mikio; Noguchi, Hiroshi; ; ; Okoshi, Minoru; Seki, Kazunari; ; Amano, Hikaru; Ueno, Takashi; Kasai, Atsushi
JAERI-M 88-232, 83 Pages, 1988/11
no abstracts in English
Saito, Fumihiro; Kasugai, Yoshimi; Seki, Kazunari; Nakane, Yoshihiro; Tani, Norio; Sato, Koichi; Yamazaki, Hirohito*; Bessho, Kotaro; Numajiri, Masaharu
no journal, ,
no abstracts in English
Nakashima, Hiroshi; Shibata, Tokushi; Sawahata, Kei; Miyamoto, Yukihiro; Nakane, Yoshihiro; Masukawa, Fumihiro; Seki, Kazunari; Sato, Koichi; Oguri, Tomomi*; Hirayama, Hideo*; et al.
no journal, ,
Aiming at studies on the latest basic science and the advancing nuclear technology, the J-PARC (Japan Proton Accelerator Research Complex) project is in progress, and the high-energy proton accelerator complex of the world highest intensity is under construction. Because of its very high beam power and its energy as well as the large-scale accelerator complex, we have encountered some difficult radiation problems in the radiation safety design. This paper reviews the radiation safety policy and methods for the design to overcome the problems on the radiation safety and the status of the radiation safety estimation for licensing of J-PARC.
Saito, Fumihiro; Masukawa, Fumihiro; Seki, Kazunari; Kasugai, Yoshimi; Miyamoto, Yukihiro
no journal, ,
no abstracts in English
Hg in J-PARC Materials & Life Science Experimental FacilitySato, Koichi; Masuyama, Koichi; Tajima, Takahiro; Yoshino, Koji; Seki, Kazunari; Kasugai, Yoshimi; Miyamoto, Yukihiro
no journal, ,
Various kinds of experiments on material and biological science have been carried out using neutrons and muons generated by bombarding the mercury and muon target with high-energy (3 GeV) and high-intense (1MW) protons in the Materials and Life Science Experimental Faculty (MLF) of Japan Proton Accelerator Complex (J-PAPC). It was found that radioactive nuclide of Hg induced in the mercury target during the beam operation was released to the environment via the ventilation system from the stack at specific times during maintenance periods. The weekly-average concentrations of Hg in the stack were 2.4 
10
1.5 10
Bq/cm
, which was much less than the legal limit by a factor of 1/10,000. The release behavior of Hg will be reported in the presentation.
Masuyama, Koichi; Sato, Koichi; Yoshino, Koji; Tajima, Takahiro*; Seki, Kazunari; Kasugai, Yoshimi; Miyamoto, Yukihiro
no journal, ,
The mercury target vessel used in the Materials and Life Science Experimental Facility (MLF) in the Japan Accelerator Research Complex (J-PARC) needs to be replaced periodically. The replacement work, which is conducted in the hot cell, associates with release of radioactive materials produced via spallation reactions between protons and mercury. Therefore we monitored radioactivity of dust and air samples in the hot cell. By the monitoring, we newly found peculiar phenomena on the behavior of radioactive products, which is important for radiation control. In this work, we will show the monitoring data and the new observation.
Kasugai, Yoshimi; Sato, Koichi; Masuyama, Koichi; Seki, Kazunari; Miyamoto, Yukihiro; Kai, Tetsuya; Harada, Masahide; Haga, Katsuhiro; Takada, Hiroshi
no journal, ,
no abstracts in English
Seki, Kazunari; Otsuka, Norikazu; Miyamoto, Yukihiro
no journal, ,
no abstracts in English
Sakashita, Koichi; Kasugai, Yoshimi; Harada, Masahide; Seki, Kazunari; Sato, Koichi; Kato, Saori; Arakawa, Yuto
no journal, ,
no abstracts in English
