Low Energy Beam Tracking Under Scattering for a Cold Electron Source in Manchester

High quality electron beams, with high spatial and tempo- ral resolution, have an important use in electron diffraction experiments to probe and study the constituents of matter. A cold electron source is being developed based on elec- tron ionisation from an atom cloud trapped by using AC magneto-optical methods in the University of Manchester. The technique will produce bunches of electrons well suited for high precision and single shot electron diffraction. In this paper issues of modelling at low energies for this state of art electron source with very low energy spread are presented, with a focus on newly developed tools to model the scat- tering in the meshes used to support the extraction electric fields. The dependence on emittance growth on mesh wire thickness is studied.