A new determination of 79Se half-life

A new value of 79Se half-life was determined by the means of inductively coupled plasma mass spectrometry (ICP-MS) and liquid scintillation counting (LSC) on a sample source isolated from a nuclear reprocessing solution. The procedure used to extract Se from the complex sample solution consisted in liquid–liquid extraction and ion exchange chromatographic methods. The concentration of 79Se was measured using ICP-MS coupled with electro-thermal vaporisation to eliminate potential isobaric interferences. The activity was measured using LSC after γ-ray spectrometry to check the contribution of residual radioactive contaminants. From these results, the half-life of 79Se was found to be 3.77 (19)×105a.