High quantum yield Tb3+ doped glass scintillator based on Ta2O5 and La2O3 in mixed glass former for synchrotron and medical x-rays imaging applications

Abstract

In this work, high quantum yield glass scintillator based on Ta₂O₅ and La₂O₃ in mixed glass former (SiO₂+B₂O₃) for synchrotron and medical x-rays imaging applications were developed. Glasses were fabricated by conventional melt quenching method in the ratio of xTb₂O₃ - 10Ta₂O₅– 20La₂O₃ - 10SrO – 10SiO₂ - (50-x)B₂O₃ (x = 0, 1, 3, 5, 7, 9, 11, 13, 15). The results indicated that an increase in Tb₂O₃ content enhanced the density, refractive index, molar volume, ion concentration, and effective atomic number of the glass, thereby making it heavier and more interaction with x-rays. Additionally, the reduced inter-ionic distance implies that the Tb³⁺ ions are closer together. The closer ion concentration leads to quenching of photoluminescent light at 7.0 % mol of Tb₂O₃ and a decrease in decay time value. The quantum yield achieved a maximum value of 77.5 % at the same concentration of Tb₂O₃. Absorption spectra clearly showed peaks at 486, 1903, and 2201 nm, indicating Tb³⁺ ion in the glass matrix. The seven emission peaks were observed correspond to electron transitions from the ⁵D₄ level to the ⁷F_{j (j=0,1,2,3,4,5,6)} states, respectively. Scintillation light was studied through radioluminescence spectra, and similar patterns were observed in photoluminescence. Scintillation decay times were measured using pulse x-ray excitation and results comparable to photoluminescence decay times in the millisecond range were obtained. High-quality images with maximum spatial resolution of 10 lp/mm were demonstrated using synchrotron and medical x-rays with the developed glass scintillator. The glass developed with 7.0 % mol of Tb₂O₃ has properties that make it suitable for use as a scintillator in high-resolution X-ray imaging devices.