Digital pulse shape algorithms for scintillation-based neutron detectors

We discuss the application of digital pulse shape algorithms to n/γ pulse shape discrimination (PSD) in a boron-enriched liquid scintillator, where the use of digital techniques has potential applications for neutron monitors. High-speed flash analogue-to-digital converters (ADCs) have opened up new possibilities for scintillator detector systems based upon digital event-by-event data acquisition. Using an 8-bit 1 GS/s waveform digitiser, we sampled the scintillation detector signals with nanosecond time resolution to extract event parameters such as pulse height and rise time. Hence we have studied the variations in pulse shape and risetimes for gamma rays and neutrons and the quality of separation of these events. Even using a simple 10-90% risetime algorithm, we observe good gamma/neutron separation, and we present the PSD figure-of-merit obtained using this digital technique. Significant PSD between gamma events and the charged particles events produced from neutron capture was not observed.