Compositional impacts of high CdO content on the structure and radiation shielding efficiency of CoO–Na2O–B2O3 glass system

Abstract

Here, this study investigated the structural changes and radiation shielding efficiency of a borate glass host modified by varying cadmium oxide (CdO) concentrations. The glass composition consisted of boron oxide (B2O3; 80:56 mol%), sodium oxide (Na2O; 19.6 mol%), and cobalt oxide (CoO; 0.4 mol%), with cadmium oxide (CdO; 0:24 mol%). The glass structure was analyzed utilizing mass density and FT-infrared spectroscopy (FTIR) in the 400 to 1600 cm−1 range, while radiation shielding properties were investigated utilizing the online Phy-X software in the 0.284–1.333 MeV energy window. Notably, the addition of CdO significantly impacted the glass density, increasing it by approximately 93 % as the added CdO concentration rose from 0 to 24 mol% (i.e., from 2.507 g/cm3 to 4.849 g/cm3). FTIR analysis revealed a concurrent increase in BO4 structural units with increasing CdO/B2O3 ratios. This observation was supported by the calculated N4BO4/(BO3+BO4) ratio, which increased from 40.73% for the CdO-free sample to 52.00% for the highest CdO content. This increase in BO4 units, denser than BO3 units, explains the observed density increase. Conversely, the concentration of non-bridging oxygens decreased from 10.14% to 4.34% with increasing CdO contents, indicating a more tightly packed glass network. Radiation shielding studies demonstrated that increasing CdO concentration from 0 to 24 mol% enhanced the shielding efficiency, evidenced by a decrease in the half-value layer parameter (HVL). The radiation protection efficacy (RPE) also increased from 0.214 to 0.426 for the CdO-free sample to the sample containing 24 mol% CdO at the investigated energy level. This finding highlights the superior shielding capability of the CdO-rich sample. Furthermore, the transmission factor (TF) was investigated for a constant thickness of 0.75 cm for glasses. The CdO-rich sample exhibited a lower TF compared to the CdO-free sample, particularly at lower energies. This finding confirms that, for a given thickness and energy, raising the cadmium oxide content in the current composition leads to an observed mitigation in the transmitted radiation.