Gamma ray shielding behavior of Li${}_2$O-doped PbO-MoO${}_3$-B${}_2$O${}_3$ glass system

In this work, five glasses for radiation shielding applications in the composition of (30 + x) PbO-5 MoO${}_3$-(25 - x) Li${}_2$O-40 B${}_2$O${}_3$ (where x = 0, 5, 10, 15 and 20 mol%) have been prepared. The density increases from 4.354 to 6.578 g cm${}^{-3}$ and the molar volume decreases from 25.144 to 22.520 cm${}^3$ with the replacement of Li${}_2$O by PbO. The indirect and direct band gap energies decrease from (2.2870-2.2297) eV and (2.9619-2.8660) eV, respectively, as lead content increases from 30 to 50 mol%. In addition, the refractive index of the samples lies between 2.6214 and 2.6429. Geant4 simulation code has been used to evaluate the gamma photon transmission through the prepared samples. Pb50Li5 sample has lower transmission fraction among the studied glasses. For the 2-cm glass thickness, the transmission fraction of Pb30Li25 sample was found to be 0.433 while at the same thickness the transmission fraction of Pb50Li5 sample is 0.265. At 1173 keV, the HVL values were found to be 1.752 cm for Pb50Li5 and 2.693 cm for Pb30Li25 glasses. At the same photon energy, the MFP values were calculated to be 2.529 cm and 3.886 cm for the Pb50Li5 and Pb30Li25 samples, respectively. Due to the higher Pb content existing in the Pb50Li5 glass, this glass effectively blocks the gamma rays compared to the other samples.