Size matters: Radiation shielding superiority of borate glasses with nano vs. micro ZnO

In this study, the melt quenching technique was used to fabricate the glass samples have the general formula: 20PbO-15BaO-(65-x)B 2 O 3 -xZnO, x = 5, 10 and 15 mol%. For each composition, two types of glasses were fabricated: the first using micro-ZnO and the other one using nano-ZnO. The LAC "linear attenuation coefficient" values are determined experimentally between 0.0595 and 1.333 MeV. According the data, it is seen that the LAC enhances with incorporation of ZnO (regardless the ZnO is in micro- or nano-sized). Therefore, adding ZnO into the given glasses improves their shielding effectiveness. On other hand, when comparing the impact of ZnO particle size on the LAC values, the results demonstrated that nano-ZnO exhibits a greater LAC than micro-ZnO. For instance, at 0.662 MeV, the RSE “radiation shielding efficiency” for the glass with 5 mol% micro- and nano-ZnO are 53.29 and 54.43 % respectively, while they are 54.37 and 55.96 % for 10 mol% micro- and nano-ZnO. The results demonstrate that the TVL “tenth value layer” values for the samples with micro-ZnO are higher than those for the glass with nano-ZnO. For example, at 0.059 MeV, the TVL for the glass with 5 % micro-ZnO and nano-ZnO are 0.150 and 0.142 cm, respectively, while at 0.662 MeV, they are 6.050 and 5.859 cm, respectively. Accordingly, ZnO nanoparticles serve as an effective radiation shield.