To date, it is no longer necessary to demonstrate the contribution and the usefulness of field evaporation simulation to understand and to interpret atom probe tomography (APT) analyses [1, 2]. In addition, recently, simulation has been also used to perform APT data reconstruction [3]. There are many commonly used simulation models, from sub-atomic scale [4, 5] up to atomic scale [2], according to the specific studied phenomena. Nevertheless, it appears today a need to have simulation models at lower scale (ie mesoscopic scale), such as level set methods [6]. Even if, these models show qualitative agreement with experimental data in 2D simulation [7], it is no completely the case in 3D, where some improvements remain to be performed [8]. In this paper, a new field evaporation simulation in 3D at the mesoscopic scale is presented. The aptitude of this new approach to reproduce APT experimental observations, while maintaining low computational and memory resources, is demonstrated through the simulation of analyses of complex microstructures under laser irradiation.

In this model, the surface is defined by an assembly of meshes, which amounts to perform a surface triangulation (figure 1. a). This step introduced the mesoscopic approach of the simulation. Furthermore, it is realized in such ways that each mesh has the same surface (editable simulation parameters), at the initial step of the simulation. It is then possible to adjust the scale of the simulation to features of interest. To reflect the experimental evaporation rate, all the meshes vertices are continuously displaced. For each vertex, the displacement direction is estimated using the normal direction of its surrounding meshes and the amplitude, using the evaporation probability, also from its surrounding meshes (Pj), defined as follow: