Digital pulse shape discrimination technique for liquid scintillation detector EJ-301

Abstract

A digital pulse shape discrimination (PSD) system has been built using a high speed digital oscilloscope NI-5772 and tested with an EJ-301 liquid scintillation detector. The sampling frequency of this system is 1.6 Gs/s. In this work, the charge comparison method, the rise time method and the zero-crossing time method are used to perform neutron-gamma discrimination. Experimental results show that the studied digital PSD algorithms can discriminate neutron and gamma rays in mixed radiation fields. The digital rise time method shows the optimal neutrongamma discrimination with integration parameter RC of 10000 ns. Moreover, the zero-crossing time method is investigated through CR-R 1 C 1 and CR-R 1 C 1 -R 2 C 2 shaping networks. It is found that for the same pair of values for the two kinds of network, the CR-R 1 C 1 -R 2 C 2 shaping network presents better neutron-gamma discrimination with R 2 C 2 of 5 ns. In addition, through the investigation of the distribution of neutron and gamma peaks for different energy regions, the relationship between the ionization density of liquid scintillation detector and the contribution of slow component in the light outputs is demonstrated. K: Digital signal processing (DSP); Particle identification methods; Scintillators, scintillation and light emission processes (solid, gas and liquid scintillators) 1Corresponding author.