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Pshenichnikov, A.; Nagae, Yuji; Kurata, Masaki
no journal, ,
Takahashi, Yuya*; Omori, Takashi*; Yamashita, Yu*; Kaneko, Masaaki*; Asano, Kazuhito*; Morita, Keisuke; Suzuki, Hideya*; Matsumura, Tatsuro
no journal, ,
no abstracts in English
Kitayama, Yoshiharu; Terasaka, Yuta; Sato, Yuki; Torii, Tatsuo
no journal, ,
To ensure the safety of workers working at the Fukushima Daiichi Nuclear Power Station (FDNPS), a technology to measure the distribution of radioactive materials in the working environment is required. In order to develop a new gamma-ray imager that can compensate for the shortcomings of existing gamma-ray imagers, the feasibility of a gamma-ray detector that does not require a shield was examined by simulation. There are pinhole cameras and a Compton camera as a technology for imaging radioactive material distribution. Since the pinhole camera can identify the source direction in one event, the image reconstruction is easy, and there is a possibility that it can be applied to quantitative measurement. However, the total weight is too heavy to be suitable for remote measurement because a shield is required. Since the Compton camera does not require a shield, it is small and light, and remote measurement is possible. However, multiple events are required to estimate the source direction, and the cone drawn at that time becomes noise, and the S/N ratio of the image is lowered. We propose a novel gamma-ray imager such as a pinhole camera that does not require shields. In this study, we verified the principle of a directional gamma-ray detector that does not require a shield.
Koshigoe, Koki*; Sato, Isamu*; Miyahara, Naoya*; Suzuki, Eriko; Osaka, Masahiko; Matsuura, Haruaki*
no journal, ,
For the waste management of radioactive concrete in the Fukushima Daiichi Nuclear Power Station, the Cs penetration behavior into concrete focused on the effects of aggregates was investigated by small-scale leaching tests of concrete with various contents of aggregates into CsI or CsCl dissolved water solution. The distribution in depth direction and chemical state of Cs were measured by using XRF and EXAFS, respectively. It was found that the Cs concentration and coordination number of O with Cs changed according to the content of aggregates. These results suggested importance of the effect of content of aggregates.