A hybrid radioassay technique for multiple beta-emitter mixtures using liquid and NaI(Tl) scintillation spectrometers

Multiple pure-beta and beta-gamma emitter mixtures can be reliably radioassayed using a combination of a liquid and a NaI(Tl) scintillation spectrometer. The method of least squares has been applied to the radioassay of relatively low-activity samples. This system removes the difficulty of analysing beta-emitter mixtures with very similar liquid scintillation pulse height distributions, such as 3H, 51Cr and 125I. All that is required for the technique is a quenched standard sample set of the nuclides to be analyzed and calibration standard samples for the gamma-emitters.