Correlation analysis between precipitation, soil radon gas and gamma exposure rate at rainfall case

Gamma exposure rate is an important measurement parameter for environment radiation monitoring. Usually, an HPIC (High Pressure Ionization Chamber) or an NaI(Tl) scintillation detector is used in order to measure the gamma exposure rate. The contributors of the gamma exposure rate were known to be composed of the cosmic rays and the crust radiations of Earth. Many studies were conducted to explain the reason of radiation field changes including studies of radon gas in soil. In this study, to analyze the correlation between the gamma exposure rate and soil radon concentration at rainfall, an active radon detector (RAD7) and 3x3 inch NaI(Tl) scintillation detector were set up at the monitoring post at Daegu. And the data of gamma exposure rate retrieved from IERNet (Integrated Environmental Radiation Monitoring Network) of Korea Institute of nuclear safety was analyzed. In this paper, the relation between the gamma exposure rate, the soil radon gas concentration and the amount of precipitation were studied for ERMS monitoring post in Daegu, in the case of rainfalls. As result of the analysis, the increase of radon concentration is strongly correlated with cumulative precipitation with R-squared of 0.927, while the increase in gamma exposure rate is somewhat weakly correlated with cumulative precipitation with R-squared of 0.741.