Mesh refinement for finite element field computations in electron optics

This paper presents a structured mesh refinement technique for the finite element method in electron optics. The technique is based upon using equipotential and flux lines on a trial potential distribution to generate the refinement mesh. For rotationally symmetric electron lenses, the method provides greater continuity of the axial field distribution derivatives than other mesh refinement techniques. For three dimensional electrostatic structures, the results show that the structured mesh refinement method can be used to improve the accuracy of field computations at points close to curved metal boundaries.