A simplified γ-γ coincidence method to measure the activity of radionuclide

A simplified γ-γ coincidence method for activity measurement when a sample containing multiple γ-ray emitters is proposed. This method can be applied when a γ-γ cascade process occurs in the radionuclide of low detection efficiency. And the activity can be calculated from the full-energy peak count rate of the cascade particles in each detector and the corresponding full-energy-full-energy coincidence count rate. To verify this simplified method, it was compared with numerous γ-γ coincidence methods using Monte Carlo simulation . Limitations and applicability of these methods are discussed. In addition, to validate this method in real environments, a digital coincidence measurement system using two NaI(Tl) detectors was developed. The measurements were performed on a standardized 60 Co source and a standardized 60 Co source in the presence of a 137 Cs standardized source. • Proposed a simplified method based on 2-D coincidence spectrum to measure the activity of nuclide which a γ-γ cascade process exists. • The method was verified by Monte Carlo simulation and experimental measurements.