Fast neutron response of Li-6 enriched CLYC and CLLB scintillators within 0.9-5.2 MeV

The performance of two Li-6 enriched elpasolite scintillators Cs2LiYCl6 : Ce3+ (CLYC) and Cs2LiLaBr6 : Ce3+ (CLLB) were investigated using mono-energetic fast neutrons generated by a 3 MV tandem accelerator. The Pulse Shape Discrimination (PSD) ability, response and energy resolution to fast neutrons and scattered slow neutrons were studied. The 6Li enriched CLYC had excellent discrimination ability between neutron and gamma rays with the Figure of Merit (FOM) value better than 2.4. An Artificial neural network (ANN) model could discriminate fast neutrons and scattered slow neutrons effectively with an accuracy of 97%, which render the Li-6 enriched CLYC capable to detect thermal neutrons with high efficiency and the energy spectrum of fast neutrons simultaneously. The quenching factors are calculated to be 0.92 and 0.48 for the Cl-35(n, p)S-35 and Cl-35 (n,)P-32 reaction, while the detection efficiency is about 0.1%-0.75% for fast neutrons within the energy range of 0.9-5.2 MeV. Unlike CLYC, CLLB was only sensitive to slow neutrons, and the discrimination ability between neutrons and gamma rays is worse than CLYC, while the ANN model exhibit better performance which has an accuracy of 97%.