Design, synthesis, and characterization of Pb-free tellurite glasses for radiation shielding applications

The melt and quench technique was used to create a new TeO2-Li2O-MoO3 glass system with the objective of providing alternative and new shielding materials for radiation safety purposes. The synthesized glasses were studied by means of their physical, thermal, and radiation shielding characteristics. It was demonstrated using Raman and FTIR spectroscopy that the insertion of Li2O and MoO3 resulted in a superimposed reduction of all Te units, including TeO3+1 and TeO3 with non-bridging oxygen, via the formation of Te(short)-O-Mo and a coordination change from MoO4 to MoO6. The densities of the prepared glasses were relatively high, having values between 4.48 and 5.11 g/cm3. Compared with TeO2-pure glass, the values for Tg and Tx substantially decrease with Li2O and MoO3 insertion. However, among prepared samples, there is only a small fluctuation in both characteristic temperatures, suggesting high thermal/composition stability. FLUKA simulations were used to estimate the photon, proton, electron, alpha-particle, and carbon ion shielding parameters for beam energies ranging from 15 to 15,000 keV. With changes in the chemical designation of the synthesized glasses, the mass attenuation coefficient of photons and stopping powers of charged radiation changed, gradually increasing with glass density and decreasing with Li2O and MoO3 insertion. In addition, the ability of the glasses to moderate fast neutrons declined with increases in the MoO3 and Li2O weight contents. On the contrary, the total cross section of thermal neutrons improved as glass density decreased and Li2O and MoO3 content increased. The synthesized glasses, through the evaluated parameters, showed better radiation shielding capacity compared to existing shields such as concrete and commercial RS-series glass shields.