<scp> <scp>Eu</scp> </scp> ³⁺ ‐Activated Borogermanate Scintillating Glass with a High <scp> <scp>Gd</scp> </scp> ₂ <scp> <scp>O</scp> </scp> ₃ Content

Abstract

Eu 3+ ‐activated borogermanate scintillating glasses with compositions of 25 B 2 O 3 –40 GeO 2 –25 Gd 2 O 3 –(10− x ) La 2 O 3 – x Eu 2 O 3 were prepared by melt‐quenching method. Their optical properties were studied by transmittance, photoluminescence, Fourier transform infrared ( FTIR ), Raman and X‐ray excited luminescence ( XEL ) spectra in detail. The results suggest that the role of Gd 2 O 3 is of significance for designing dense glass. Furthermore, energy‐transfer efficiency from Gd 3+ to Eu 3+ ions can be near 100% when the content of Eu 2 O 3 exceeds x = 4, the corresponding critical distance for Gd 3+ – Eu 3+ ion pairs is estimated to be 4.57 Å. The strongest emission intensities of Eu 3+ ions under both 276 and 394 nm excitation are simultaneously at the content of 8 mol% Eu 2 O 3 . The degree of Eu – O covalency and the local environment of Eu 3+ ions are evaluated by the value of Ω t parameters from Judd–Ofelt analysis. The calculated results imply that the covalency of Eu – O bond increases with the increasing concentration of Eu 3+ ions in the investigated borogermanate glass. As a potential scintillating application, the strongest XEL intensity under X‐ray excitation is found to be in the case of 6 mol% Eu 2 O 3 , which is slightly different from the photoluminescence results. The possible reason may be attributed to the discrepancy of the excitation mechanism between the ultraviolet and X‐ray energy.