A comparison on three neutron-gamma discrimination methods used with NE213, UGLLT and UGAB scintillators.

Liquid organic scintillators are widely used in radiation measurements. NE213 (or its equivalent, BC-501A) in neutron-gamma discrimination (NGD) and two new scintillators, UGLLT and UGAB, in alpha-beta discrimination are two common examples. In this paper, the NGD capabilities of these three scintillators were studied and their figure-of-merits (FoMs) were measured for comparison. The three different NGD methods used in this study were zero-cross method (ZCM), charge integration method (CIM) and filtered charge integration method (FCIM), where ZCM was analog and the two other methods were digital. A 1.1 μCi point 22Na gamma ray source and 100 mCi cylindrical 241Am–Be neutron source (3.5 cm diameter by 5 cm length) were used for the energy calibration and the NGD, respectively. The FoM values for NE213, UGLLT and UGAB at 100 keVee discrimination bias (i.e. , the preset threshold voltage, generally expressed in keVee unit, upon which the generated pulse-heights are recorded) using ZCM, CIM and FCIM methods were (1.060 ± 0.037, 1.430 ± 0.040, 1.70 ± 0.054), (0.910 ± 0.029, 1.270 ± 0.018, 1.460 ± 0.027) and (0.890 ± 0.027, 1.200 ± 0.020, 1.460 ± 0.026), respectively. Although UGAB scintillator exhibits the least discrimination quality, one can choose an appropriate neutron-gamma discrimination method to improve its FoM. The low-temperature flammability, toxicity and high-evaporation properties of NE213 scintillator may motivate some researchers to use UGLLT and UGAB scintillators as alternatives to NE213, however, by selecting the most efficient discrimination method. [ABSTRACT FROM AUTHOR]