Examination of radiation effects on Cs2LiYCl6:Ce3+ scintillators using a 100 MeV proton beam

Cs2LiYCl6:Ce3+ scintillator is worthwhile to study, since it has good pulse shape discrimination capability which lead to thermal or fast neutron detection based on the reactions of the constituent elements of Li and Cl. In this study, the effects of proton dose on the scintillation performance of CLYC were measured to check its feasibility for space exploration. A 100 MeV proton beam generated by the Korean Multi-Purpose Accelerator Complex (KOMAC) was used for irradiation of the crystal. The pulse shape discrimination (PSD) for gamma-rays and thermal neutrons as a function of protons dose was used as a standard method for evaluation. After removing gamma-rays background from neutron signal by PSD, we examined the effect of the proton dose on the scintillator based on the electron equivalent energy induced by thermal neutron. When a proton beam was irradiated on the CLYC scintillator at 1 krad, we found a decrease in the light yield by approximately 50% and a rapid increase in the background radiations. Therefore, the detector for gamma-ray measurements was considered unsuitable in high-level proton fields, such as in a low-Earth orbit, owing to the activation problem in CLYC scintillators. However, given that the neutrons can be separated from gamma-rays by the PSD, conducting in situ calibrations using the peaks of the thermal neutron channels up to the maximum dose of the order of several krad through a neutron spectrometer is possible.