Gamma ray shielding and thermoluminescence investigation of bismuth added heavy metal oxide glasses

Nowadays, as a replacement for lead which is a toxic element, bismuth glasses are explored extensively due to their higher density for radiation attenuation applications. This work is an attempt to portray the radiation shielding and thermoluminescence response of bismuth in the borosilicate glasses of composition (60-x) B2O3- 20SiO(2)- xBi(2)O(3)- 12ZnO- 8BaO with x = 0, 2, 4, 6, 8, 10 and 12 mol% coded as ZBiB glasses. The estimation of theoretical values of gamma ray shielding parameters with Cs-137 gamma source such as mass attenuation coefficient, effective atomic number, half value layer and mean free path was carried out using Photon Shielding and Dosimetry software and compared with experimental results. The data naturally showed high attenuation values for ZBiB-12 glass. Higher bismuth samples were observed to possess dark brown colour and opaque nature. The applicability of such glasses for gamma dosimetry using thermoluminescence (TL) property was also examined by irradiating the glasses with 3 kGy of 1.25 MeV gamma radiation from Co-60 source. The radiation created defect centers by breaking Zn-O, Bi-O, Si-O, B-O and Si-O-B bonds resulting in high intensity TL peaks. The role of Bi as thermoluminescence quenching agents has been evaluated in the present investigation. Computer Glow Curve Deconvolution was done for the TL curves to get the information regarding trapped charges such as activation energy, half-life and frequency factor. Among the high bismuth incorporated glasses, ZBiB-8 sample exhibited comparably higher TL intensity at 576.1 K with half-life of 23 years.