Pure CaF₂ crystal for fast neutron detection

Pure CaF₂ crystals have been widely used for optical functional crystals due to their good optical properties, mechanical properties, and chemical stability. This study discovered the crystal's pulse shape discrimination (PSD), proving it a promising scintillator for fast neutron detection via the ⁴⁰Ca neutron capture reaction. Luminescence emission spectra were studied by X-ray luminescence measurements. The maximum emission peak was observed between 250 and 300 nm, corresponding to self-trap exciton emission. The crystal response to gamma, alpha, and neutron were studied under ¹³⁷Cs, ²⁴¹Am, and ²⁵²Cf radiation sources, respectively. The difference in gamma and alpha decay times enabled the PSD capability of pure CaF₂. Large neutron reaction cross-sections, PSD capability, and good chemical stability make pure CaF₂ crystal candidates for fast neutron beam monitoring detectors. Moreover, the crystal can be used for ⁴⁰Ca(n,p)⁴⁰K and ⁴⁰Ca(n,α)³⁷Ag neutron capture cross-section study.