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.