Measurement of radon concentration in water using direct dpm method of liquid scintillation counter

摘要

For measuring radon (~(222)Rn) concentration in water with a direct method, a two-layer sample is measured by a liquid scintillation counter (LSC). A calibration factor for an LSC is generally evaluated by a comparison measurement of a radium (~(236)Ra) standard. However, it is difficult to use the ~(236)Ra standard in Japan. Thus, we studied a direct dpm method based on the integral counting method for a two-layer sample. The optimized window values of three efficiency tracing points for the direct dpm method were determined to be 50-2000, 75-2000, and 100-2000 keV. It was determined that a calibration factor of 5 could be used with an LSC.