Determination of Dose Distributions by High-energy Electrons in Alumina Pellets Using Monte Carlo Simulations

Abstract

Electron beam accelerators are broadly used to study the effects of ionizing radiation on the properties of materials. These accelerators are also used to study radiation effects in some important ceramics such as alumina. The produced high-energy electrons at MeV energies will deposit doses that are typically non-uniformly distributed within the entire material. Such distributions provide valuable information regarding the degree of internal and surface changes owing to the irradiation. In the present study, the Monte Carlo (MC) method was used to obtain the dose distributions of high-energy electrons to alumina ceramic in pellet form. The distributions obtained via MCNP5 (Monte Carlo N-Particle version 5) were normalized by experimental values. For the energy of the simulated electrons, both monoenergetic and polyenergetic source electron energies were evaluated. The distributions of the depth-dose, depth-energy, and the top and bottom surface 2D dose mesh were obtained. Results showed that either assumption of monoenergetic or polyenergetic source electron energies resulted in similar depth-dose curves. The depth-energy results showed a larger spread in energy distributions for polyenergetic as compared to monoenergetic source electrons; nonetheless, the average doses for both were similar. The 2D dose maps showed a uniform dose distribution at the top pellet surface and a significantly non-uniform distribution at the bottom of the pellet. These results emphasize the effectiveness of the MC method in determining non-uniform doses within materials, which can be used in quantifying the changes in the material properties at each separate area of the electron irradiated object.