In recent years, the rapid advancement of nuclear energy and technology has led to the expanded utilization of special nuclear materials in more applications. In the pursuit of enhancing nuclear materials monitoring capability, extensive research has been dedicated to fast neutron multiplicity measurement systems based on liquid scintillation detector. However, these detectors are predominantly manufactured by foreign companies, such as Eljen and Saint-Gobain.

This study aims to evaluate the performance of a self-developed neutron detector based on EJ301 liquid scintillator.

First of all, a 7.62 cm-diameter, 5.08 cm-thick liquid scintillator was applied to the development of neutron detector named EJ301-Z liquid scintillator detector, and ²²Na and ⁶⁰Co gamma sources were employed to calibrate this detector for establishing the relationship between incident particle energy and deposited energy. Subsequent tests on the neutron-gamma discrimination performance of the detector were conducted with a ²⁵²Cf neutron source, and figure-of-merit (FOM) values at different energy thresholds were calculated based on the charge comparison method. Then, comparison of the neutron-gamma discrimination performance of the detector with Eljen's EJ301 and Saint-Gobain's BC501A liquid scintillation detectors were conducted to evaluate the detector's performance relative to these commercially available models. Finally, the results obtained using the time-of-flight method were used to validate the results of the charge comparison method, providing an assessment of the absolute neutron-gamma discrimination performance of the liquid scintillator detector.

The experimental results show that, the EJ301-Z detect outperforms both Eljen EJ301 and Saint-Gobain BC501A detectors in terms of neutron-gamma discrimination, with an energy threshold of 150 keV, the rate of gamma mis-discrimination (RGMD) of EJ301-Z detector with the charge integration method is as low as 0.1‰.

The developed detector of this study demonstrates superior neutron-gamma discrimination performance compared to commercially available models from Eljen and Saint-Gobain.