Effects of Eu concentration control on crystal growth and scintillation properties for Eu:LiSrAlF6 crystals

Eu doped LiSrAlF6 (Eu:LiSAF) crystals with various Eu concentrations were grown by a micro-pulling-down (μ-PD) method and the effects of Eu concentration control on crystal growth and scintillation properties for Eu:LiSAF crystals were investigated as a neutron scintillator. As-grown Eu0.3%:LiSAF crystal had no visible inclusion while milky parts were observed in the crystals with higher Eu contents. The secondary phases with the chemical composition of EuF2 or EuF3 in the Eu:LiSAF matrix were observed for the crystals with high Eu contents while the secondary phase couldn’t be observed in the powder XRD patterns. In the radioluminescence spectra of Eu:LiSAF crystals under α-ray irradiation, emission peaks around 375 nm originated from 5d–4f transition of Eu2+ ion were observed. The light yields systematically increased with an increase of actual Eu contents in the crystals and the decay times were 1490–1620 ns.