Eco-friendly lead-free Yb₂O₃ doped transparent phosphate glasses for radiation shielding applications

Melt-quenched Yb³⁺-doped phosphate glasses with 50P₂O₅-(50 - x)BaO-xYb₂O₃ (x = 0, 0.5, 1.0, 2.0, 3.0, 4.0 mol %) composition have been studied for radiation shielding, photon trajectories, and transport phenomena using theoretical and multipurpose Particle and Heavy Ions Transport System (PHITS). The glasses were initially characterized by x-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, and the absorption edges analyzed through Tauc and Urbach plots. XRD endorsed the amorphous structure of the samples, while FT-IR spectra demonstrated characteristic phosphate network features. Band gap analysis revealed the highest optical band gap energy for 4 mol% Yb₂O₃ (3.69 ±0.05 eV) compared to lower concentrations of Yb₂O₃ and the glass host (3.47 ±0.03 eV) indicating the optimum transparency and insulating nature. Radiation shielding properties were assessed via mass and linear attenuation coefficients, half- and tenth- value layers for gamma-ray attenuation energy range 0.015 to 15 MeV. Moreover, transport properties such as mean free path, effective atomic number, conductivity, and electron density are evaluated. A PHITS simulation study with relative errors is used to compare the parameters estimated from the Phy-X/PSD database. Theoretical and simulation study indicated that Yb³⁺ doping enhances gamma-ray shielding, with the 2 mol% Yb₂O₃-doped glass exhibiting the greater fast neutron removal cross-section. In contrast, the 4 mol% Yb₂O₃ sample showed a better charge particle stopping power and shorter projected ranges for electrons, protons, helium, and carbon ions. Monte Carlo simulations using the PHITS code confirmed that these Yb³⁺-doped barium phosphate host lead-free transparent glasses offer effective and eco-friendly protection against ionizing radiation such as photons, electrons, hadrons, and heavy ions, positioning them as promising alternatives for sustainable radiation shielding solutions.