Automatic optimization strategy for the design of circular multipolar magnets

This paper presents an optimization procedure for the design of circular magnets of multipolar symmetry in the presence of an iron screen. The procedure is based on the combined use of field calculations and optimization techniques and can be applied when the field is generated either by a distribution of currents or of magnetic materials. The numerical optimization technique uses the positions and/or orientations of the field generating elements as parameters (currents or permanent magnets). The technique has proved to be very effective in obtaining a good uniformity of field in a large fraction of the magnet volume. It should reduce the subsequent shimming operations. The method is almost completely automatic and simpler than other standard methods normally used to design new magnet geometries which are based on field calculation programs and ‘manual’ optimization procedures.