Bismuth's role in quaternary thulium doped tellurite glasses: Achieving optical clarity and radiation shielding

This study explores the impact of bismuth oxide (Bi 2 O 3 ) on the optical and radiation shielding properties of transparent, lead-free thulium-doped bismuth borotellurite radiation shielding glass. The investigated glass composition follows the formula [(TeO 2 ) 75 (B 2 O 3 ) 25 ] 98- x (Bi 2 O 3 ) x [Tm 2 O 3 ] 2 , where x = 0 mol%, 5 mol%, 10 mol%, 15 mol%, 20 mol%, 25 mol% and 30 mol%. All glass samples remain transparent, with an optical bandgap ( ) exceeding 3.1 eV, ensuring visible light transmission. Radiation shielding data from Phy-X and XCom reveal interactions of the photoelectric effect, Compton scattering, and pair production, with minimal relative difference in mass attenuation coefficient ( ) which is between 0.05 to 0.56. At 0.662 MeV photon energy, the 20 mol% and 25 mol% Bi 2 O 3 glasses exhibit significantly higher Phy-X values than other samples, except RS 520 glass, which contains 71% PbO. Despite incorporating only up to 25 mol% Bi 2 O 3 , these glasses outperform others in density, half-value layer ( ), and mean free path ( ). Correlating and , the 20 mol% Bi 2 O 3 glass is the best candidate for transparent radiation shielding glass due to its wide optical bandgap which prevents ionization of trapped holes. Significantly, the linkage between and molar refraction was also discovered based on the particle size influence on both parameters.