Program package for the computation of lenses and deflectors

In this paper a set of computer programs for the design of electrostatic and magnetic electron lenses and for the design of multipoles for electron microscopy and lithography is described. The two-dimensional field computation is performed by the finite-element method. In order to meet the high demands on accuracy, the programs include the use of a variable step in the fine mesh made with an automeshing procedure, improved methods for coefficient evaluation, a fast solution procedure for the linear equations, and modified algorithms for computation of multipoles and electrostatic lenses. They allow for a fast and accurate computation of electron optical elements. For the input and modification of data, and for presentation of results, graphical menu driven programs written for personal computers are used. For the computation of electron optical properties axial fields are used. (orig.)