Discrimination of neutron and gamma spectrum using a method based on digital filters

In this study, the Monte Carlo based simulation code, Geant4, was used to model the 2-inch NE-213 detector and Am-Be source available in Sharif University Faculty of Energy and the neutron and gamma spectrum for this source in the NE-213 detector could be achieved. Furthermore, a circuit based on analogue Constant Fraction Method (CFM) was used in laboratory to get the neutron and gamma spectrum of the same source to be used for further comparisons. For next step, three digital filters named as Triangular, Trapezoidal and Flat Top Cusp were scripted in MATLAB not only to see how each filter performs in discrimination of these two spectrums, but also to find the optimum values for the effective parameters in each of the filters by comparing the filter outputs with the results obtained from constant fraction method in lab. As it appeared, in triangular filter for k=11, trapezoidal filter for k=10 and L=5 and in the flat top cusp filter for k=10 and L=20, best results were obtained. By comparing the results for these values in each filter, it was shown that the trapezoidal filter performed the best in spectrum discrimination.