Activity Measurement of 90Sr using the Liquid Scintillation TDCR Method

90Sr is a pure β decay nuclide，but because its decay progeny 90Y half-life is only 64 hours，it will have an impact on the accurate determination of 90Sr activity，given its own nature，the analysis method of 90Sr is relatively complex，the liquid scintillation triple-to-double coincidence ratio method (TDCR) is used to measure the 90Sr radioactivity activity，in the state of equilibrium of the 90Sr-90Y daughter. The total counts of 90Sr and 90Y were measured，and the calculation of the total TDCR efficiency will be calculated according to the sum of the two nuclide efficiencies. The calculation of the TDCR efficiency was first performed by using the BataShape program to calculate the 90Sr and 90Y energy spectra，and the efficiency of counting β-particles in the scintillating liquid based on the free-parameter model by using the efficiency calculation program written and obtaining the efficiency curves of 90Sr/90Y，combined with the experimental results of the TDCR values and efficiency curves are combined to achieve the absolute measurement of 90Sr activity with a relative standard uncertainty of 0.36%，which provides a reliable tool for environmental monitoring and nuclear safety fields.