Optical, photon interaction, and radiation shielding performance of Ho2O3-doped borate glasses modified with ZnO and CaO

In this work, a series of Ho₂O₃-doped borate-based glasses modified with ZnO and CaO were synthesized using the melt-quenching technique and systematically investigated. The experimental mass density increased from 2.98 g/cm³ to 3.29 g/cm³ with modifiers, directly enhancing photon interaction probability. The Tauc plot analysis showed a decrease in optical band gap from 3.879 to 3.739 eV. Geant4 Monte Carlo simulations agreed well with XCOM predictions, with deviations below 4 %, further validated by the Kolmogorov-Smirnov test (D_max < 0.89 %, p ∼1). At 0.5 MeV, linear attenuation coefficient ($\mu$) ranged from 0.260 cm^-1 to 0.287 cm^-1, surpassing several standard shielding materials. Different shielding parameters have also been calculated and assessed in this study. SRIM analysis showed stopping powers peaking at low energies, with alpha particles exhibiting higher −dE/dx and shorter ranges than protons. Overall, the combination of high transparency, density-driven photon attenuation, and rare-earth contributions make these glass systems promising for optical devices, medical windows, and radiation protection.