Single Crystal Growth, Optical Properties and Neutron Response of Ce3+ Doped LiCaAlF6

Ce2% : (LiCaAlF6)-Li-6 ((6)LiCAF) single crystal (nominal composition) with 2 mm in diameter and 50 mm in length was grown by the micro-pulling-down method. Emission from the perturbed Ce3+ centers was observed in an alpha-ray excited radioluminescence. The neutron response was compared with Li-glass (GS20, Saint-Gobain) using Cf-252. The scintillation decay time of Ce2% : (6)LiCAF is 38 nsec, which is twice as short as that of GS20. Using Hamamatsu photomultiplier H7416 the photoelectron yield about a half of that of GS20 has been measured for the Ce : (6)LiCAF single crystal. Considering the light yield of GS20 (6000 phot/neutron) and the spectral correction due to the different emission peak position in both materials, the light yield of Ce : (6)LiCAF single crystal is estimated about 4200 phot/neutron.