Determination of ⁷⁹Se/⁷⁸Se Ratio in Calibration Standards for ⁷⁹Se Accelerator Mass Spectrometry (AMS) Measurement

Using liquid scintillation counting (LSC) to determine the ratio of ⁷⁹Se/⁷⁸Se in the irradiated sample was reported. Firstly, the γ and β spectrum of irradiated sample was measured to find out the interferefering nuclide. Then, the irradiated sample was heated up to remove the interferefering nuclide from the sample as much as possible. At last, the activity ⁷⁹Se was determined by LSC, and the ratio of ⁷⁹Se/⁷⁸Se was determined to be (5.44±0.23)×10^－5. It provides reliable standard sample for AMS measurement.