An alternative approach for simulating the field evaporation process in atom probe tomography is presented. The model uses the electrostatic Robin's equation to directly calculate charge distribution over the tip apex conducting surface, without the need for a supporting mesh. The partial ionization state of the surface atoms is at the core of the method. Indeed, each surface atom is considered as a point charge, which is representative of its evaporation probability. The computational efficiency is ensured by an adapted version of the Barnes-Hut N-body problem algorithm. Standard desorption maps for cubic structures are presented in order to demonstrate the effectiveness of the method.
Keywords: Barnes–Hut algorithm; Robin’s equation; atom probe tomography; meshless simulation; point charge model.