Investigation on the luminescent properties of Eu3Â +-activated dense oxyfluoride borogermanate scintillating glasses

Eu3 +-activated dense B2O3-GeO2-BaF2-10LaF3-(37-x)Gd2O3-xEu2O3 (0 ≤ x ≤ 12.5) scintillating glasses were synthesized by melt-quenching method. Their optical properties were characterized by transmittance, excitation and emission spectra, and X-ray excited luminescence (XEL) spectra in detail. The total content of Gd2O3 and LaF3 rare-earth agents is as high as 47 mol% in borogermanate glass, which ensures glass density exceed 6.0 g/cm3. Energy transfer from Gd3 + to Eu3 + ions is verified by excitation and emission spectra. High efficiency of this transfer process is confirmed by both Gd3 + emission intensity and the average distances for Gd3 +-Eu3 + ion pairs. The degree of Eu-O covalency and the local environment of Eu3 + ions are evaluated by the value of Ωt parameters from the Judd-Ofelt analysis. It is found that the covalency of EuO bond increases with increasing Eu3 + concentration. The optimal concentration of Eu3 +-activated borogermanate scintillating glass under both ultraviolet and X-ray excitation is determined. It reveals that the integral scintillation efficiency is about 4% of the standard Bi4Ge3O12 (BGO) scintillating crystal.