Valence state of dopant and scintillation properties of Ce-doped Sr ₃Y(BO₃)₃ crystal

A transparent Ce:SYB crystal was grown by employing the floating zone method in a dry-air atmosphere, and the growth rate was 1 mm/h. The feed/seed rods were formed by sintering raw powder at 1000 °C for 24 h. The Ce content in the grown crystal was measured by electron probe microanalysis and was found to be very low (approximately 0.1 at%). Ce LIII XANES measurement showed that 90% of the Ce in the sintered powder was quadrivalent. On the other hand, approximately 80% of the Ce in the grown crystal was trivalent. Emission bands centered at 415 nm corresponding to the 5d-4f transition of Ce³⁺ were observed when the excitation wavelength was 365 nm. The decay time under this condition was approximately 12.26±0.45 ns. The light yield strength excited by an α-source was approximately ∼6% of that from the Li-glass.