earticle

영어

Background: Liquid scintillation counters (LSCs) are commonly used as an analytical method for detecting 222Rn in groundwater because they involve a simple sample pretreatment and allow high throughout with an autosampler. The Quantulus 1220 is the best-selling LSC in Korea, but its production was stopped. Recently, a new type of LSC, the 300SL, was introduced. In this study, the 300SL was compared with the Quantulus 1220 in order to evaluate the ability of each apparatus to detect 222Rn in groundwater. Materials and Methods: The Quantulus 1220 and 300SL were used to detect the presence of 222Rn. Radon gas was extracted from a groundwater sample using a water-immiscible cocktail in a LSC vial. The optimal analytical conditions for each LSC were determined using a 222Rn calibration source prepared with a 226Ra source. Results and Discussion: The optimal pulse shape analysis level for alpha and beta separation was 80 for the Quantulus 1220, and the corresponding pulse length index was 12 in the 300SL. The counting efficiency of the Quantulus 1220 for alpha emissions was similar to that of the 300SL, but the background count rate of the Quantulus 1220 was 10 times lower than that of the 300SL. The minimum detectable activity of the Quantulus 1220 was 0.08 Bq·L-1, while that of the 300SL was 0.20 Bq·L-1. The analytical results regarding 222Rn in groundwater were less than 10% different between these LSCs. Conclusion: The 300SL is an LSC that is comparable to the Quantulus 1220 for detecting 222Rn in groundwater. Both LSCs can be applied to determine the levels of 222Rn in groundwater under the management of the Ministry of Environment.