Optical and radiation shielding studies on La2O3-mixed zinc-borovanadate glasses

Abstract

Lead-free glasses of composition, (ZnO)_0.3–(V₂O₅)_0.3-x–(B₂O₃)_0.4–(La₂O₃)_x; x = 0.01–0.05 were made by melt-quenching procedure. Their amorphous nature was established. FTIR studies revealed that functional groups are present in the glasses. Band (indirect) gaps obtained from UV–Vis absorption spectra, increased with increase in La₂O₃ content from 2.505 to 2.828 eV. Urbach energy and refractive index were decreased from 0.397 to 0.292 eV and 2.544–2.440, respectively, with La₂O₃. Various optical parameters have been estimated. These suggest the suitability of these glasses for photoelectronic applications. Using Phy-X/PSD and XCOM softwares, gamma- and neutron-shielding parameters were evaluated for photon energy range of 0.15–15 MeV. Mass and linear attenuation coefficients were found to increase with increase in La₂O₃ mole fractions. Minimum half value and tenth value layers (HVL, TVL) of the glasses at 0.015 MeV, are found to lie between 0.007 and 0.006 cm, and 0.0260 and 0.0211 cm, respectively. Maximum exposure build-up factors (EBF) at 0.4 MeV for 40 mean free path (MFP) were found in the range of 199.37–110.26 and energy absorption build-up factors (EABF) in the range of 407.98–220.11. Removal cross-sections for fast neutrons were estimated to be in the range of 0.1001–0.1036 cm⁻¹. Radiation-shielding parameters, such as HVL, TVL, MFP, Z_eff, Z_eq, EBF and EABF values were found to be lesser and Σ_R values were greater than reported values for several boro-vanadate glasses, commercial glasses, IL, HSC, BM, ordinary concrete and ilmenite concretes. Radiation-protection efficiency of the present glasses was found to increase with La₂O₃ content and decrease with photon energy. Therefore, these glasses are proposed for both gamma- and neutron-shielding applications.