Neutron/gamma discrimination performance test for self-developed plastic scintillation detectors

Abstract

BackgroundPlastic scintillators have potential for application in neutron detection. Two sizes (ø2.54 cm×2.54 cm, ø5.08 cm×5.08 cm) of plastic scintillators are self-developed by scientific research team in the school of physics, Sichuan University.PurposeThis study aims to experimental test the neutron/gamma (n-) discrimination performance for two self-developed plastic scintillators.MethodsA photomultiplier tube (PMT) was used to build detection systems, and high speed oscilloscope (LECROY HDO6104A) was employed to sample signal of detector for the energy calibration of the self-developed plastic scintillator. The pulse amplitude spectrum of 137Cs γ radiation source was measured and compared with the MCNP5 simulation spectrum to obtain the position information of the Compton edge and accurately calibrate the energies of γ rays. The data obtained from a 241Am-Be neutron source were analyzed using the charge integration method, and parameters such as the figure of merit (FOM), peak-to-valley ratio for neutrons, and the proportion of leaked neutrons over all neutron events were used to quantify the n-γ discrimination in different energy zones. The detection efficiencies of two self-developed plastic scintillators relative to the Commercial off-the-Shelf (COTS) EJ-299-33A were determined.ResultsThe results show that the FOM of ø2.54 cm×2.54 cm self-developed plastic scintillator is higher that of ø5.08 cm×5.08 cm self-developed plastic scintillator, and the detection efficiency of two self developed plastic scintillators relative to EJ-299-33A is about 0.49 and 1.0, respectively.ConclusionsThe performance of the ø5.08 cm×5.08 cm self-developed plastic scintillator is comparable to that of the COTS plastic scintillator EJ-299-33A with near the same discrimination ability.

Keywords

• plastic scintillator
• energy calibration
• n-γ
• discrimination ability quantification