AN AUTOMATIC RADON SENSOR FOR BOREHOLE MEASUREMENTS

The understanding of radon migration in the earth's crust is important in many applications, such as radiation protection in residential bui ldings, uranium ore prospecting, or earthquake prediction. Recent stud ies also show correlations of radon exhalation with short-periodic roc k stresses induced by tidal forces. The borehole radon sensor presente d can be used to investigate subsurface radon migration in situ. It is capable of measuring the concentration of both radon and thoron in ai r with a time resolution of less than an hour and a detection limit of approximately 1 Bq m(-3), even in volumes as small as 100 ml. The sen sor is fully automated and can be calibrated in situ. (C) 1997 America n Institute of Physics.