Radon in water measurement system based on the membrane-based air-water separation method

Radon is a natural radionuclide that can cause cancer of the lungs and stomach upon inhalation and ingestion, respectively; therefore, the radon content in groundwater needs to be continuously monitored. If the concentrations are high, it may take a long time to stabilize the detector contaminated with radon daughters. To overcome this problem, a radon in water measurement system based on the membrane-based air-water separation method is proposed to reduce the waiting time between measurements. The system consists of a water separation part, mixer, and radon measurement part, and it separates radon from water and controls the radon concentration. In this study, the behavior of radon was theoretically evaluated, and the separation and mixing of radon were tested. By analyzing the radioactivity of the water sample and the amount of radon separated within a certain period, it was determined that 86% of the radon was separated from the water and measured by the detector. The count rate of the air-mixing experiment was in good agreement with the theoretical model with coefficients of determination of 0.97, 0.91, and 0.95 for mixtures with ratios of air from water to external air as 1:0, 1:1, and 1:3, respectively.