Effect of mechanical ball milling on the microstructure and radiation shielding performance of nano-PbO

Abstract

This study probes the shielding efficacy of nano-PbO, examining the effects of milling on its microstructure and the consequences on X- and gamma-ray absorption. Characterization techniques, including XRD, Raman spectroscopy, TEM, and positron annihilation spectroscopy of commercial (milled for 10, 20, and 40 h) samples, as well as the synthesized PbO, reveal that milling induces a partial phase transformation from orthorhombic to tetragonal, alters particle morphology, and increases pore volume. Notably, milling does not significantly affect X-ray attenuation. The growing particle size with lower surface area, reduction of vacancy-type defects, and expanded pore size resulting from ball milling negatively influenced the probability of interaction of gamma-rays (<250 keV). Principal component analysis highlights the interplay between particle size, surface area, defect density, and pore size in determining shielding efficacy. This investigation underscores the importance of considering multiple parameters, beyond particle size, to optimize the radiation shielding performance of any material.