Crystal growth and luminescence characterizations of halide scintillators K2LaBr5:Eu2+

Abstract

Recent researches have shown that Eu2+ ion heterovalently doped rare earth halide scintillators attract the attention of researchers. In this paper, the transparent K2LaBr5 scintillation crystals of centimeter size doped with heterovalent Eu2+ were successfully grow by the vertical Bridgman technique. X-ray powder diffraction analysis shows that the crystal has an orthonormal structure with space group Pnma(62). A small amount of Eu2+ doping does not change the internal structure of the crystal.The transmittance, the UV–visible excited spectrum and emission spectrum, X-ray excited luminescence spectrum, Photoluminescence decay time and scintillation pulse decay time have been measured at room temperature. The results show that the crystal has strong luminescence intensity, and the maximum emission peak is about 430 nm. The photoluminescence decay time of K2LaBr5:xmol.%Eu2+(x = 0.5, 1, 2) are 5.56 μs, 5.67 μs and 7.03 μs, respectively. The decay time of K2LaBr5:Eu2+ crystal under 137Cs 662 keV radiation is nanosecond, indicating that the K2LaBr5:Eu2+ crystal has fast decay characteristics and excellent time resolution performance.