Optimization of the optical properties and γ-buildup factors of Na₂O–CaO–SiO₂ glasses reinforced with Cd²⁺ and Fe³⁺ ions: potential use in optical and radiation shielding applications

Sodium calcium silicate glasses with CdO and Fe₂O₃ heavy transition metals in the 16Na₂O–(34 − x) CaO − xCdO–(50 − y) SiO₂–yFe₂O₃ compositions (x = 8.50, and 17.0 mol %, and y = 2.5, 5, and 10 mol%) have been prepared using traditional melting technique. The optical properties of the prepared glasses were investigated using a UV–Visible spectrophotometer. Gamma-ray buildup factors were calculated using Phy-X/PSD software. The results of X-ray diffraction exhibited the amorphous nature for all synthesized glasses. The effect of the CdO/CaO and Fe₂O₃/SiO₂ replacements on the linear optical properties and γ-ray buildup factors along with different mean free path values (0.5–40 mfp) of the prepared glasses has been examined. The values of the direct optical gap (E_g(d)) varied from 5.035 ± 0.001 eV to 3.94 ± 0.001 eV. The Urbach's energy E_U varied randomly when using CdO and Fe₂O₃ instead of CaO and SiO₂, which confirms a change in structural disorder in the investigated glasses. The refractive index (n) of the glass samples increased from 2.666 ± 0.001 to 3.174 ± 0.001 with the introduction of CdO and Fe₂O₃ into the glass matrix. The sample 16Na₂O–17CaO–17CdO–47.5SiO₂–2.5Fe₂O₃ possessed the highest values of the equivalent atomic number (Z_eq) at high photon energies. In terms of exposure (EBF) and energy absorption (EABF) buildup factors, the sample coded as D6 had the lowest EBF and EABF values among all the samples examined. Overall, the findings indicate that CdO/CaO and Fe₂O3/SiO₂ replacements improve enhancing optical and radiation shielding abilities. Finally, these findings have the potential to position these newly prepared glasses as promising optical and shielding materials with the lowest fabrication cost for various protective applications in different fields.