Radon leakage problem in determination of radon by liquid scintillation

The paper presents briefly the experimental data on radon leakage from liquid scintillation vials in measurement of radon with liquid scintillation counter. Seal tests of vials of three kinds have been made. Results show that all tested caps of the vials made of glass can not meet the needs to seal radon in the vial. The problem was basically solved by putting a layer of rubber (bicycle inner tube, 1 mm thick) and a layer of aluminized polyester (0.01 mm thick) between the vial and the cap as cushion in place of the polyethylene inner cap or other types of gasket. It is suggested that seal ability to radon of vials be tested before using a new brand of commercial scintillation vials for radon determination and remedial action, if necessary, be taken to guarantee the accuracy of analytical results