Further investigations of a simple counting technique for measuring mixtures of two pure β-emitting radionuclides

A simple liquid scintillation counting technique to measure the activity composition of a mixture containing two known pure β-emitting radionuclides was recently developed at the NMISA. The method has been applied to various two-component mixtures of 32P, 33P and 35S, primarily to gauge the effect of spectral energy differences on the methodʹs ability to extract the individual activities. Excellent results were obtained for mixtures of 33P and 35S, radionuclides with similar, low β energies. Mixtures containing the high-energy β-emitter 32P were more difficult to resolve, although quenching of the counting sources with CHCl3 improved mixture resolution.