Luminescent properties of Tb3 +-activated B2O3–GeO2–Gd2O3 scintillating glasses

Tb3 +-activated 25B2O3–40GeO2–(35 − x)Gd2O3–xTb2O3 scintillating glasses were prepared by melt-quenching method. Their structure and luminescent properties were characterized by transmittance, Raman, photoluminescence and X-ray excited luminescence (XEL) spectra in details. A high Gd2O3 content is necessary to ensure borogermanate glass with density up to 5.7 g/cm3. Energy transfer efficiency from Gd3 + to Tb3 + ions, and critical distances for both Gd3 +-Tb3 + and Tb3 +-Tb3 + ion pairs were calculated, respectively. The optimal concentration of Tb3 +-activated borogermanate scintillating glass under both ultraviolet and X-ray excitation is determined. It reveals that the integral scintillation efficiency is about 30% of the standard Bi4Ge3O12 (BGO) scintillating crystal.