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Masuyama, Koichi; Arakawa, Yuto; Otsuka, Yoshikazu; Yokosuka, Yoshiyuki; Kobayashi, Makoto; Akiyama, Isamu; Shimizu, Isamu
no journal, ,
no abstracts in English
Oi, Motoki; Harada, Masahide; Kai, Tetsuya; Aizawa, Kazuya; Sato, Koichi; Masuyama, Koichi; Kasugai, Yoshimi
no journal, ,
In the J-PARC Materials and Life Science Experimental Facility (MLF), material science experiments using muon and neutron beam are performed. In the MLF, proton beam power was 300KW at May 2014 and it is planning to enhance to 1MW. For proton beam enhancement, we performed evaluation of the shielding performance of the neutron beam instruments. As a result, dose on the shield surface of 16 neutron instruments are sufficiently low for 1MW proton beam operation. However, 4 neutron instruments show high dose rate in particular neutron beam conditions. For these neutron instruments, we have checked the drawings and recalculate the shielding performance and considered a cause. Then based on the measurement results, some shield are added for these four neutron instruments and dose rate are reduced sufficiently to 1MW proton beam operation.
Sato, 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 2.4 101.5 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.
Saito, Hiroyuki*; Higurashi, Koichi*; Masuyama, Daisuke*; Oki, Shigeo; Ohgama, Kazuya; Maeda, Seiichiro
no journal, ,
no abstracts in English
Harada, Masahide; Uchida, Toshitsugu; Sekijima, Mitsuaki; Haga, Katsuhiro; Kogawa, Hiroyuki; Kinoshita, Hidetaka; Takada, Hiroshi; Sato, Koichi; Masuyama, Koichi
no journal, ,
no abstracts in English
Harada, Masahide; Kawakami, Kazuhiro*; Aizawa, Kazuya; Soyama, Kazuhiko; Sato, Koichi; Masuyama, Koichi; Kasugai, Yoshimi
no journal, ,
no abstracts in English
Kasugai, Yoshimi; Sato, Koichi; Masuyama, Koichi; Seki, Kazunari; Miyamoto, Yukihiro; Kai, Tetsuya; Harada, Masahide; Haga, Katsuhiro; Takada, Hiroshi
no journal, ,
no abstracts in English
Masuyama, Koichi; Ishii, Daiki; Taki, Kosei; Kirihara, Yoichi; Nidaira, Atsushi; Tachibana, Haruo; Kawasaki, Katsuya
no journal, ,
no abstracts in English