Computational model of alpha-decay damage accumulation in zircon

Atomic-scale computer simulations are used to study defect accumulation and amorphization due to alpha decay in zircon (ZrSiO4). The displacement cascades, which represent U-234 recoil nuclei from alpha decay of Pu-238 in zircon, are generated using a crystalline binary collision model. The stochastic production of defects in the crystal lattice, recombination of defects, and the identification of amorphous regions are followed within the framework of a kinetic Monte Carlo simulation. Within the model, amorphous regions are identified as those having a critical density of Zr vacancies. The simulation predicts the interstitial content and amorphous fraction as functions of dose that are consistent with experimental data at 300 K for Pu-238-doped zircon, which indicates that the simulation model for behavior in zircon at 300 K is reasonable. (C) 2004 Elsevier B.V. All rights reserved.