Enhancing gamma-ray shielding with Bi2O3-Enriched BTBi glasses: Optimal balance of attenuation and glass transparency

A host glass of barium-magnesium-boro-tellurite (BTBi0) was produced and reinforced with 10, 20, 30, and 40 mol% of Bi2O3 (BTBi1, BTBi2, BTBi3, and BTBi4) to enhance its gamma rays shielding efficiency. The structural, optical, and attenuation properties of the produced BTBi glass series were studied. Penetration of Bi2O3 up to 30 mol% into the proposed host network enriches it with non-bridging oxygens (NBO) units, while the glass containing 40 mol% was enriched with bridging oxygens (BOs) units, which arose as a result of the role of the Bi3+ ion in disrupting the borate network, leading to the BO4⇋BO3 conversion. The conversion role of Bi2O3 was clearly evident in the behavior of the molar volume, oxygen packing density, and packing density. The results of Raman shift showed the formation of the structural units of the boro-tellurite network and BiO6 units within the glass network. The compositional changes brought about by Bi2O3 agreed perfectly with the results of the optical properties of the studied glass. The red shift in optical absorption spectra, the reduction in the optical band gap, and the augmentation of Urbach energy up to 30 mol% of Bi2O3 occurred mainly as a result of the formation of NBOs units. In contrast, at 40 mol% of Bi2O3, the continuation of the red shift, the decrease in the optical band gap, and the increase in the Urbach energy, despite the increase in BOs compared to the NBOs, are attributed to the high polarizability of Bi3+ and the formation of BiO6 units. The transparency of the glass increased to about 85 % with increasing Bi2O3 up to 30 mol%, but decreased to 70 % at 40 mol%. The ability of the considered glasses to attenuate gamma rays was examined using Phy-X/PSD software. The results showed that the attenuation ability improved significantly with increasing Bi2O3 concentrations, where the required thickness to attenuate gamma rays was reduced by 48.505–77.134 % at 40 mol% of Bi2O3. Based on the high attenuation ability and transparency of the studied BTBi glasses, they can be used as a protective shield against gamma rays in nuclear applications that require visual monitoring.