Year
2016
Abstract
Neutron detection technologies are at the forefront of the effort to support objectives of the interdiction, search, and characterization of special nuclear materials. Pulse shape discrimination (PSD) is an efficient approach of distinguishing between simultaneously detected neutrons and gamma rays. In this study, a wavelet-based PSD was used. The discrete wavelet transform is implemented using Matlab in the time domain of a single waveform, and the resulting set of coefficients is converted into the power of the waveform, which is further analyzed with numerical integration. For each waveform, partial integrals are calculated on different sections of the coefficients’ curve, and a radiation identification value (RID) is calculated as their ratio. The RID serves as a threshold value for neutron-gamma discrimination. Beyond the RID threshold, the signal is categorized as a neutron event; below it, the signal is categorized as a photon event. The PSD algorithm and the Matlab code were developed and tested on a set of neutron and photon waveforms measured with the CLYC detector. The measured figure of merit (FOM) for CLYC, which quantifies the PSD quality, indicates efficient neutron-gamma separation.