Scintillation properties of Eu and alkaline metal co-doped LiCaAlF₆

Very low amount of Eu and alkali metal (Na, K, Rb and Cs) co-doped LiCaAlF₆ crystal scintillators were prepared by using the micro-pulling down method to investigate the origin of the light yield enhancement and the fast luminescence of LiCaAlF₆-based scintillators. In X-ray and α-ray induced scintillation spectra, the host and Eu²⁺ 5d-4f transition emission appeared around 300–500 nm as a broad shape and 370 nm as a sharp line, respectively. At a synchrotron facility (UVSOR), the excitation spectra under vacuum ultra violet (VUV) photons excitation were investigated, and the results confirmed new excitation bands around 80–90 nm as well as the band gap of LiCaAlF₆ (~113 nm). Fast luminescence with the lifetime of few ns was confirmed in K, Rb and Cs doped samples under VUV and X-ray excitations. The detector property was tested, and K co-doping improves the pulse shape discrimination performance.