A model for ion-neutral scattering in the nano-aperture source

Abstract

When ions are extracted from the nano-aperture ion source, they inevitably interact with the neutral particles. In this chapter, a model for such interactions is presented. An important finding is that the current and the brightness tend to keep increasing with increasing particle density, despite increasing ion-neutral scattering. Another result is that the spread in energies in the beam can be reduced as a consequence of more ion-neutral scattering. The model developed forms a basis to be used in simulations that also consider coulomb interactions. Besides presenting a model for advanced calculation, simplified analytically expressions are introduced that can help to understand a particular configuration or to quickly estimate the performance.