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 (μl, μm) at different photon energies. In addition, the theoretical values of μm for γ-Al2O3 micro-particles were calculated using the WinXCom computer program and compared with the experimental values of μm for NPs of γ-Al2O3. Furthermore, in order to evaluate the impact of γ-irradiation on these NPs, the experimental values of μl and μm for γ-Al2O3 NPs, before and after receiving 20 kGy dose of γ-irradiation, were investigated. It was observed that μm 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.