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 Ta<inf>2</inf>O<inf>5</inf> and La<inf>2</inf>O<inf>3</inf> in mixed glass former (SiO<inf>2</inf>+B<inf>2</inf>O<inf>3</inf>) for synchrotron and medical x-rays imaging applications were developed. Glasses were fabricated by conventional melt quenching method in the ratio of xTb<inf>2</inf>O<inf>3</inf> - 10Ta<inf>2</inf>O<inf>5</inf>– 20La<inf>2</inf>O<inf>3</inf> - 10SrO – 10SiO<inf>2</inf> - (50-x)B<inf>2</inf>O<inf>3</inf> (x = 0, 1, 3, 5, 7, 9, 11, 13, 15). The results indicated that an increase in Tb<inf>2</inf>O<inf>3</inf> 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 Tb<inf>2</inf>O<inf>3</inf> and a decrease in decay time value. The quantum yield achieved a maximum value of 77.5 % at the same concentration of Tb<inf>2</inf>O<inf>3</inf>. 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 ⁵D<inf>4</inf> level to the ⁷F<inf>j (j=0,1,2,3,4,5,6)</inf> 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 Tb<inf>2</inf>O<inf>3</inf> has properties that make it suitable for use as a scintillator in high-resolution X-ray imaging devices.