The influence of γ-irradiation on molecular structure and mass attenuation coefficients of γ-Al2O3 nanoparticles.

In this research, γ-Al₂O₃ nanoparticles (NPs) were synthesized by using the sol–gel process. The photon attenuation properties of these NPs were obtained by measuring the linear and mass attenuation coefficients (μ_l, μ_m) at different photon energies. In addition, the theoretical values of μ_m for γ-Al₂O₃ micro-particles were calculated using the WinXCom computer program and compared with the experimental values of μ_m for NPs of γ-Al₂O₃. Furthermore, in order to evaluate the impact of γ-irradiation on these NPs, the experimental values of μ_l and μ_m for γ-Al₂O₃ NPs, before and after receiving 20 kGy dose of γ-irradiation, were investigated. It was observed that μ_m of γ-Al₂O₃ NPs decreases after receiving γ-irradiation because of increasing the photon's energy, which indicates the changes in the molecular structure of NPs after γ-irradiation. Moreover, the structural properties of NPs were evaluated by UV–Vis spectroscopy, x-ray diffraction patterns, and scanning electron microscopy images. UV–Vis spectroscopy showed an absorption peak at 212.5 nm before γ-irradiation, and the absorption peak of NPs disappeared when γ-irradiation was started. The average crystalline size was determined to be 3.65 nm in the sample before γ-irradiation and 9.29 nm in the sample with the maximum dose of 20 kGy. The results of scanning electron microscopy show an increase in particle size from 6.5 nm in a non-irradiated sample up to 9 nm in a sample with the highest γ-irradiation dose. [ABSTRACT FROM AUTHOR]