Investigation on radioxenon background in Mutsu related to CTBT verification

Kijima, Yuichi ; Yamamoto, Yoichi ; Oda, Tetsuzo

The International Noble Gas Experiment (INGE) is being carried out for global measurement networks of radioactive noble gas (xenon), as part of building of the international verification regime of the Comprehensive nuclear-Test-Ban Treaty (CTBT). Since there are many nuclear facilities and medical institutions in Japan and its neighboring countries, which may be possible sources of radioxenon, it is important to understand the behavior of normal radioxenon background for high-precision detection of underground nuclear tests. Therefore, for the purpose of the investigation on radioxenon background in Northeast Asia region, the measurement of radioxenon was conducted in Mutsu city, Aomori in 2012, and the results showed that radioxenon background in Mutsu was regionally specific and different from that in Takasaki. In 2014, the additional measurement was carried out at the same place for further investigation. This report describes the results of background measurement in Mutsu city in 2014.