Pandemic-inspired construction of radon measurement field for testing a new alpha imaging detector

Morishita, Yuki   ; Kearfott, K.*; Wakaida, Ikuo ; Miyabe, Masabumi   

The author has been developing a new alpha imaging detector for decommissioning the Fukushima Daiichi Nuclear Power Plant. COVID-19 restricted business travel within and outside the country, making it difficult to test the developed detectors. So, inspired by the Prof. Kearfott's lab in the University of Michigan, the author has been building his own radon measurement field near his office. The author measured the radon concentration in several places near his office using Rn monitor (AlphaGUARD Bertin Technologies, Montigny-le-Bretonneux, France), and found that the radon concentration was high in the underground space of the concrete building. The Rn concentration was about 200 Bq/m. When the measurement was carried out with a Rn progeny detector (poCAMon: Personal Continuous Air Monitor (CAM), SARAD GmbH, Dresden, Germany), the peaks of Po: 6.0 MeV alpha particles and Po: 7.7 MeV alpha particles of Rn progeny were clearly observed. Because there is little ventilation in this underground space, the Rn concentration is relatively constant and suitable for detector testing. Even with the COVID-19's restriction on travel, the author was able to proceed with experiments with the construction of its own experimental environment. The author will use the built environment to test various new alpha imaging detectors.