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Kurita, Yoshiyuki; Okazaki, Tsutomu; Maeda, Satoshi; Yoda, Tomoyuki; Saegusa, Jun
no journal, ,
no abstracts in English
Hoshi, Katsuya; Yoshida, Tadayoshi; Tsujimura, Norio; Tsuchiko, Yasuhiro*; Suto, Yudai*; Okada, Kazuhiko
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.
Yoshida, Tadayoshi; Hoshi, Katsuya; Tsujimura, Norio; Okada, Kazuhiko
no journal, ,
no abstracts in English
Tsujimura, Norio; Yoshida, Tadayoshi; Hoshi, Katsuya
no journal, ,
no abstracts in English
Shibamichi, Masaru; Shimomura, Ryohei*; Takeishi, Minoru; Saegusa, Jun
no journal, ,
Conversion method for air dose-rates from inside to outside of a monitoring car was investigated in the Fukushima environment. Two detectors were installed at different height in the car, and Ratio between two different height dose rates in the car and dose rate above 1m height at outside same position were measured at more than 20 locations in the Fukushima environment. Conversion from dose rate in the car to that of outside were evaluated taking into account for the ratio between two dose rates measured in the car. As a result, conversion from dose rate in the car to that at outside were improved.
Harada, Masahide; Oi, Motoki; Sekijima, Mitsuaki; Kai, Tetsuya; Takada, Hiroshi; Kasugai, Yoshimi
no journal, ,
no abstracts in English
Satou, Yukihiko*; Sueki, Keisuke*; Sasa, Kimikazu*; Minowa, Haruka*; Yoshikawa, Hideki; Fujiwara, Kenso; Nakama, Shigeo; Adachi, Koji*; Igarashi, Yasuhito*
no journal, ,
Radioactive particle including high density cesium were released caused by the Fukushima Daiichi nuclear disaster. In this study, we analyzed distribution of radioactive particle and its characteristic about obtained soils and dusts. As a result, radioactive particles were confirmed from soil sample. In particular, 100 micro meter in diameters particles were found at the point of north-northwest direction approximately 7km from the nuclear power plant. Found particles resembled an elementary composition and surface state of the particle found in the 20km northwest from nuclear power plant and Tsukuba.
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.
Maeda, Satoshi; Yoda, Tomoyuki; Okazaki, Tsutomu; Otani, Shuichi; Saegusa, Jun
no journal, ,
no abstracts in English