Tailoring bismuth borate glasses by incorporating PbO/GeO2 for protection against nuclear radiation

Nuclear radiation shielding capabilities for a glass series 20Bi(2)O(3)-xPbO-(80-2x)B2O3-xGeO(2) (where x=5, 10, 20, and 30 mol%) have been investigated using the Phy-X/PSD software and Monte Carlo N-Particle transport code. The mass attenuation coefficients (mu(m)) of selected samples have been estimated through XCOM dependent Phy-X/PSD program and MCNP-5 code in the photon-energy range 0.015-15 MeV. So obtained mu(m) values are used to calculate other gamma-ray shielding parameters such as half-value layer (HVL), mean-free-path (MFP), etc. The calculated mu(m) values were found to be 71.20 cm(2)/g, 76.03 cm(2)/g, 84.24 cm(2)/g, and 90.94 cm(2)/g for four glasses S-1 to S-4, respectively. The effective atomic number (Z(eff))values vary between 69.87 and 17.11 for S-1 or 75.66 and 29.11 for S-4 over 0.05-15 MeV of photon-energy. Sample S4, which has a larger PbO/GeO2 of 30 mol% in the bismuth-borate glass, possesses the lowest MFP and HVL, providing higher radiation protection efficiency compared to all other combinations. It shows outperformance while compared the calculated parameters (HVL and MFP) with the commercial shielding glasses, different alloys, polymers, standard shielding concretes, and ceramics. Geometric Progression (G-P) was applied for evaluating the energy absorption and exposure buildup factors at energies 0.015-15 MeV with penetration depths up to 40 mfp. The buildup factors showed dependence on the MFP and photon-energy as well. The studied samples' neutron shielding behavior was also evaluated by calculating the fast neutron removal cross-section (Sigma(R)), i.e. found to be 0.139 cm(-1) for S-1, 0.133 cm(-1) for S-2, 0.128 cm(-1) for S-3,S- and 0.12 cm(-1) for S-4. The results reveal a great potential for using a glass composite sample S4 in radiation protection applications.