Design of a microengineered electrostatic quadrupole lens

The design of a miniature quadrupole lens based on metallized glass electrodes mounted in two anisotropically etched silicon mounts that are separated by precision spacers is described. The analysis of conventional quadrupole lenses is first reviewed. The fabrication process is then described, and the analysis techniques are applied to the new geometry. The potential distribution near the axis is first calculated using a finite difference method. Expansion into solutions of Laplace's equation in cylindrical coordinates is then used to determine the potential distortion introduced by the microengineered mount. Design rules are given for a mount and an electrode radius that achieve minimal distortion.