Fabrication and characterization of Er3+-activated BaO–Bi2O3–GeO2 glasses for NIR emitting scintillators

We fabricated bismuth germanate glasses 20BaO–60Bi 2 O 3 –20GeO 2 having various Er 2 O 3 concentrations of 0.1 % (0.1ErBaBiGe), 0.5 % (0.5ErBaBiGe), and 1.0 % (1.0ErBaBiGe) and investigated luminescent characteristics for the fabrication of glass scintillators with near-infrared (NIR) emissions. Luminescent peaks from the transitions between the 4f states in Er 3+ appeared at approximately 532, 547, 673, 862, 989, and 1532 nm upon 520 nm excitation, and the largest quantum yield (43 %) was obtained at the Er 2 O 3 concentration of 0.5 %. They were also detected under excitation by X-rays, and the intensity reached its maximum at the Er 2 O 3 concentration of 1.0 %. A linear dependence of the NIR scintillation intensity on the dose rate was observed from the fabricated bismuth germanate glasses across the 5–50000 mGy h⁻ 1 range by using a lnGaAs photodiode, and the minimum detectable rate (5 mGy h⁻ 1 ) was close to that of Er 3+ -doped Bi 4 Si 3 O 12 and Bi 4 Ge 3 O 12 crystals.