Effect of gamma irradiation on the structure characteristics and mass attenuation coefficient of MgO nanoparticles

Abstract

Abstract In this work, the structure properties and mass attenuation coefficient of MgO nanoparticles were studied before and after gamma irradiation. The as-synthesized samples of MgO nanoparticles by sol–gel method were analyzed by XRD which suggested the double phase; cubic and hexagonal structures of the material. Crystal defects produced in the cubic and hexagonal lattice were studied before and after exposure to 20 kGy gamma irradiation in order to investigate the changes in the structure properties and mass attenuation coefficients of MgO nanoparticles. XRD data of gamma-irradiated and non-irradiated MgO nanoparticles show that the crystal size of MgO nanoparticles increases after radiation exposure. SEM images after irradiation indicated significant changes in the morphology. The UV-Visible absorption spectra of the nanoparticles were taken and the results of optical band gap of the MgO nanoparticles before and after irradiation show that the value of band gap has changed slightly due to gamma irradiation. The results of comparing experimental values of mass attenuation coefficient for non-irradiated MgO nanoparticles with theoretical values of mass attenuation coefficient for MgO microparticles calculated using the NIST XCOM show that the mass attenuation coefficient not only depends on the effective atomic number but also depends on the size of the particles. Also, it is observed that the mass attenuation coefficient of MgO nanoparticles decreases after the irradiation which shows that by increasing the size of the nanoparticles, the mass attenuation coefficient decreases. It could be because the cross-section of photon interaction with materials depends on the surface to volume ratio of nanoparticles. The experimental results also show that the linear and mass attenuation coefficient of MgO nanoparticles decrease with increasing the photon energy.