Evaluation of gamma-ray exposure buildup factors and neutron shielding for bismuth borosilicate glasses

Gamma-ray exposure buildup factor (EBF) values and neutron shielding effectiveness of bismuth borosilicate (BBS) glass systems in composition (50-x)SiO2:15B(2)O(3):2Al(2)O(3):10CaO:23Na(2)O:xBi(2)O(3) (where x=0, 5, 10, 15 and 20 mol%) were calculated. The EBF values were computed for photon energy 0.015-15 MeV up to penetration depths of 40 mfp (mean free path) by the geometrical progression (G-P) method. The EBF values were found dependent upon incident photon energy, penetration and bismuth molar concentration. In low- and high-energy photon regions, the EBF values were minimum whereas maximum in the intermediate-energy region. The fast neutron removal cross sections for energy 2-12 MeV were calculated by the partial density method. The BBS glass with 20 mol% Bi2O3 is found to be superior gamma-ray and neutron transparent shielding. The EBF values of the BBS glasses were compared with steel-magnetite concrete and lead. The investigation was carried out to explore the advantages of the BBS glasses in different radiation shielding applications. (C) 2013 Elsevier Ltd. All rights reserved.