Nuclide identification for pure beta-emitting radionuclides with very similar beta end-point energies using a liquid scintillation spectrometer

Pure-beta emitting radionuclides with very similar beta end-point energies can be identified by using a liquid scintillation pulse height analysis. Besides a liquid scintillation spectrometer, quenched sample sets for the nuclides to be analyzed are all that are required for this technique. It is important to determine the optimal channel settings in order to detect the slight difference in the scintillation pulse height distributions of the nuclides.In this study, the technique has been applied to the nuclide identification for 14C and 35S, and the lower detection limit with 95% confidence level was estimated to be 0.3 Bq/ml based on 5 ml activity sample and 60 min counting time.