Crystal growth, luminescence and scintillation properties of Eu2+:CeBr3 crystals

Eu2+:CeBr3 crystals were grown by vertical Bridgman growth method and slight aliovalent doping of Eu2+ in the CeBr3 crystal did not change the crystal structure. The X-ray stimulated luminescence, photoluminescence, decay kinetics and scintillation properties were investigated at room temperature. The X-ray stimulated luminescence spectra exhibited wide broad emission bands from 3.54 eV to 2.95 eV in the Eu2+:CeBr3 crystal with high content of 620 ppm of Eu2+, which were the overlap of the emission bands ascribed to 5d → 4f transition of Ce3+ and 4f65 d1 → 4f7 transition of Eu2+, respectively. When the content of Eu2+ was decreased to 70 ppm, another emission band centered at 2.29 eV was observed. The photoluminescence spectra showed the energy transfer from Ce3+ to Eu2+. This decreased the Ce3+ emission intensity but enhanced the Eu2+ emission intensity. The photoluminescence decay time of Ce3+ emission decreased from 14 ns to 10 ns when the content of Eu2+ increased from 70 ppm to 620 ppm. The decay time of the emission of 525 nm did not change with the excitation wavelength and Eu2+ content, which could be assigned to the excitons that were bound on Eu2+ related centers. The light output of the Eu:CeBr3 crystal under the excitation of 241Am radioactive source was less than 20.2% of Tl:NaI crystal.