Study on the applicability of the integral counting method for the determination of226Ra in various sample forms using a liquid scintillation counter

Abstract

A new counting method was developed to determine226Ra in environmental samples by separating the equilibrated222Rn into a liquid scintillator. The integral counting method, which was originally developed for isolated individual radionuclides, was extended to the mixture of222Rn and its daughters in equilibrium. The optimum measurement conditions were established by examining the energy spectrum, counting time and quenching effect. An absolute counting was practiced by extrapolating the integral counting rate-bias voltage curve with the highest gain to zero bias. The detection limit thus obtained was 3 to 4·10−13 Ci.