| Accessing time scales beyond molecular dynamics (MD) is a crucial extension to simulations of radiation damage in solids. Investigating how damage evolves is central in understanding the ageing processes in nuclear materials, from reactor components to waste-forms. This work augments MD simulations of low energy collision cascades with kinetic Monte Carlo to investigate the mechanisms and time scales of damage recovery. Simulating both the ballistic and recovery phase of radiation events allows for comprehensive analysis of both defect formation and migration. In addition, and more significantly, the time scale for recovery can be determined as a function of incident energy of the impacting particle. As a by-product of the simulations, important quantities such as threshold displacement energies and transition energy barriers are also defined. The subject of this study is rutile TiO2, a widely studied material with applications ranging from photovoltaics to chemical sensing. Its lesser-known use as a nuclear material, present in the Synroc waste form, motivates its use in this work. Additionally, the relatively simple structure rutile provides an ideal test candidate before application to more complex nuclear materials. |
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