An efficient attenuator for gamma rays and slow neutrons of elastic and transparent lead sodium zinc calcium borate glass

Aiming to produce a multifunctional efficient shield for gamma rays and slow neutrons simultaneously, a host glass of 30B₂O₃–10CaO–10ZnO–50Na₂O (BCZNPb1) was prepared and reinforced by increasing the PbO and B₂O₃ concentrations simultaneously to produce three developed glassy materials containing 10 and 35 (BCZNPb2), 20 and 40 (BCZNPb3), and 30 and 45 (BCZNPb4) mol% of PbO and B₂O₃. Significant structural changes appeared as a result of the incorporation of PbO and B₂O₃ into the proposed host glass (BCZNPb1), as the network became overcrowded with the four-coordinate tetrahedral units BO₄ and PbO₄. The structural changes were extensively studied using X-ray diffraction, density and density-based parameters, and Fourier Transform Infrared spectra. Mechanically, the formed BO₄ and PbO₄ units increased the covalent bonds and the crosslinking density within the glass network, which reflected positively on the improvement of the elastic moduli (modulus of longitudinal, shear, bulk, and Young) and the hardness of the considered glasses. The results of the optical transmittance spectra showed that the produced glassy materials had high transparency, exceeding 70%. The optical band gap and Urbach energy results confirmed the reduction of disorder within the glass network, which resulted from the formation of BO₄ and PbO₄ units. The attenuation of gamma rays and slow neutrons results showed a significant improvement with increasing the PbO and B₂O₃ concentrations, as the required half-value layers to attenuate gamma rays decreased by 61.540, 57.790, and 56.699% for the studied gamma ray energies of 661.64, 1173.23, and 1132.51 keV at 30 mol% of PbO (BCZNPb4 glass), respectively, while the required half-value layer for slow neutrons decreased by 61.409% at 45 mol% of B₂O₃ (BCZNPb4 glass). Accordingly, the produced BCZNPb4 glass has suitable mechanical properties, high transparency, and high attenuation efficiency for gamma rays and slow neutrons, making it a desirable shield in many nuclear domains.