Design and optimization of multipole lens and Wien filter systems

The differential algebra (DA) method has been employed to compute the optical properties and aberrations up to the fifth order of multipole systems containing electrostatic and magnetic round, quadrupole, hexapole and octopole lenses, and Wien filters. A new software package has been developed, which computes the geometrical and chromatic aberrations up to the fifth order by using a single DA ray trace. It also has an optimization module where a weighted set of aberrations can be minimized by the automatic adjustment of a set of user-defined system variables. In this paper, we present our new method for designing and optimizing multipole systems including Wien filters, and illustrate its application with three relevant examples.