Diffuse X-ray scattering from ion-irradiated materials: a parallel-computing approach

Abstract

A computational method for the evaluation of the two-dimensional diffuse X-ray scattering distribution from irradiated single crystals is presented. A Monte Carlo approach is used to generate the displacement field in the damaged crystal. This step makes use of vector programming and multiprocessing to accelerate the computation. Reciprocal space maps are then computed using GPU-accelerated fast Fourier transforms. It is shown that this procedure speeds up the calculation by a factor of ∼190 for a crystal containing 109unit cells. The potential of the method is illustrated with two examples: the diffuse scattering from a single crystal containing (i) a non-uniform defect depth distribution (with a potentially bimodal defect size distribution) and (ii) spatially correlated defects exhibiting either long-range or short-range ordering with varying positional disorder.