Fabrication and Characterization of Ce-Doped LiCaAlF6–CaF2–Li3AlF6 and CaF2–LiF–Li3AlF6 Scintillators for Thermal Neutron Detection

In this study, we developed and characterized novel scintillators with Ce: LiCaAlF6–CaF2–Li3AlF6 and Ce: CaF2–LiF–Li3AlF6 ternary systems for thermal neutron detectors. The eutectics were grown by the vertical Stochbarger-Bridgman (VB) technique, and their constituent phases were identified using powder X-ray diffraction and scanning electron microscopy. Radioluminescence spectra irradiated under an Ag-target X-ray tube and confirmed the 5d-4f and self-trapped exciton luminescence derived from Ce3+. Scintillation decay and pulse height measurements were performed using 252Cf and 60Co sources. The Ce: CaF2–LiF–Li3AlF6 sample exhibited approximately 5.6 times higher effective neutron sensitivity compared with a Ce: LiCaAlF6 single crystal. A favorable decrease in the neutron discrimination threshold level (Qth) due to reduced γ-ray emission was observed. 6Li-enriched Ce: CaF-based scintillators hold potential for nuclear decommissioning applications.