Neutron/gamma-ray pulse shape discrimination with liquid scintillation detectors based on average pulses

In this paper, we present a new pulse shape discrimination (PSD) method that is based on detailed knowledge of the average detector response to radiation. Traditionally, PSD has been performed using standard methods such as charge integration. In this work, average pulses were obtained for several pulse height regions separately for neutrons and gamma rays. The average neutron and gamma-ray pulses were used in the new PSD algorithm for classification of a large number of measured pulses. This new PSD approach proves to be more accurate than the standard chargeintegration PSD for neutron and gamma rays under 70 keVee (keV electron equivalent; 450 keV neutron energy). Specifically, the improvement is approximately 40 percent for neutrons in the smallest pulse height bin considered, which was between 23 and 30 keVee (corresponding to approximately 175 keV and 225 keV neutron energy, respectively). For this pulse height bin, approximately 66 percent of the neutrons were correctly classified. The average number of correctly classified neutrons is approximately 82 percent for the average-pulses PSD method between 23 and 100 keVee (corresponding to approximately 175 keV and 670 keV neutron energy, respectively).