Abstract: Gd³⁺-sensitized Tb³⁺-doped scintillating silicate glasses with Gd₂O₃ and Tb₂O₃ concentrations up to 45wt% were prepared. Effects of different Gd₂O₃ and Tb₂O₃ concentrations on the density, refractive index and luminescence properties under UV and X-ray excitations were investigated and the energy transfer mechanisms between Gd³⁺ and Tb³⁺ analyzed and discussed. The results show that, with the increasing concentrations of Tb³⁺ and Gd³⁺, a monotonic increase in the energy transfer efficiencies from Gd³⁺∶⁶P_7/2 to Tb³⁺∶⁵H₇ is observed followed by enhanced emissions centered at 620, 583, 541 and 496nm under 273nm UV excitation. However, with X-ray excitation, the incorporation of a large amount of Tb³⁺ weakens the luminescence emission due to the increase of point defects in glass.

Key words: terbium ions, gadolinium ions, scintillating glasses, energy transfer