Energy transfer from Gd³⁺ to Sm³⁺ and luminescence characteristics of CaO–Gd₂O₃–SiO₂–B₂O₃ scintillating glasses

In this work, density, optical, photoluminescence and x-ray scintillation properties of calcium gadolinium silicoborate glass (CaO:Gd₂O₃:SiO₂:B₂O₃) have been investigated. Glasses were prepared by the conventional melt quenching technique. The results show that the density of glass increased with increasing of Sm₂O₃. The optical spectra of glass shows eleven discrete absorption bands at 360, 373, 403, 475, 944, 1077, 1225, 1368, 1468, 1520 and 1586 nm which are due to the transitions of ⁶H_5/2 to ⁴D_3/2, ⁶P_7/2, ⁶P_3/2, ⁴I_11/2, ⁶F_11/2, ⁶F_9/2, ⁶F_7/2, ⁶F_5/2, ⁶F_3/2, ⁶H_15/2 and ⁶F_1/2, respectively. The emission spectra were observed and assigned to 312, 563, 600, 646 and 703 nm by excitation at 275 nm. The emission intensity of Sm³⁺ increased with increasing of Sm₂O₃ concentration until 0.25 mol%, while decay time decrease with increasing of Sm₂O₃ content. For results of the radioluminescence (RL), they perform four emission peaks with the strongest emission at 598 nm. Glass doped with 0.35 mol% Sm₂O₃ show the highest RL emission. The integral scintillation efficiency of 0.35 mol% Sm₂O₃ doped glass was determined as 25% of commercial BGO scintillator crystal.