Crystal growth and scintillation characterizations of mixed halide scintillators K2LaBr5-xIx: Ce (x = 0, 1, 2)

Abstract

The purpose of this research is to investigate the luminescence and scintillation properties of mixed halide scintillators K2LaBr5-xIx. The crystals of K2LaBr5-xIx:2% Ce (x = 0, 1, 2) have been synthesized by high-temperature solid-phase method and grown by vertical Bridgman method. The crystals are measured by X-ray induced luminescence spectra, optical transmittance photoluminescence spectrum, photoluminescence decay time, and pulse height spectrum. Under the UV and X-ray excitation, all of the crystal samples have typical Ce3+ double peaks corresponding to the energy level shifts of 5d1→2F5/2 and 5d1→2F7/2, with emission centers ranging from 350 to 400 nm. The photoluminescence decay time of the three crystals of K2LaBr5-xIx: Ce is about 20 ns. Under 662 keV γ-rays excitation from a 137Cs source, the energy resolution is 8.2%, 15% and 10% (FWHM), respectively.