부산 금정구지역의 지하수에 포함된 라돈농도 변화 연구 |
조정숙;이효민;김선웅;김진섭; |
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A Study on the Variation of Rn-222 Concentration in Groundwater at Busan-Geumjeong area |
Cho, Jungg-Sook;Lee, Hyo-Min;Kim, Sun-Woong;Kim, Jin-Seop; |
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ABSTRACT |
In this paper, we measured the variations of radon concentrations in groundwater using low-level Liquid Scintillation Counter (LSC), an instrument for analyzing the alpha and beta radionuclides at its 10 sites around the Kumjung-Gu, north-western of Busan. Optimization of Pulse Shape Analyzer (PSA) to determinate the highest value of figure of merit (FM) was decided using Quantulus 1200 LSC with radium-226 source, the optimal PSA level was shown in the range of 100 to 110. The results show that the Minimum Detectable Activity (MDA) of radon concentrations is 0.61 $Bq{cdot}L^{-1}$ for 20 minutes in PSA level. We find that the average radon concentration in groundwater is high in granitic rock area and low in volcanic rock area. (Biotite granite : 191.39 $Bq{cdot}L^{-1}$, Micro graphic granite : 141.88 $Bq{cdot}L^{-1}$, Adamellite : 92.94 $Bq{cdot}L^{-1}$, Andesite (volcanic) : 35.35 $Bq{cdot}L^{-1}$). No significant seasonal variation pattern is observed from the long-term variation analysis from 10 selected sites. We have not seen the significant correlation of radon concentration to groundwater temperature, atmospheric temperature, atmospheric pressure and rainfall. The concentration variation is probably caused by more complex factors and processes. |
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