Optimization of integration limit in the charge comparison method based on signal shape function

A novel method is proposed to analyze neutron and gamma-ray signal shapes in liquid scintillation detectors. Specifically, the signal shape functions for a BC501 detector were characterized and a statistical model was used to analyze the discrimination of neutrons and gamma rays. The model varied the starting points of tail integration in the charge comparison method (CCM), and an optimized starting point was determined. Experimental measurements were performed to verify the model, and the results indicated good agreement. For a BC501 scintillator with 8.07 ns and 74.63 ns decay time constants we found optimal time to start the tail integration at 24 ns past the decay maximum.