3D calculations of a fixed field alternating gradient synchrotron magnet

A spallation neutron source for materials science studies is being designed at Argonne and requires a fixed field alternating gradient (FFAG) synchrotron magnet. Electrostatic field calculations in three dimensions were made to obtain the unsaturated magnet pole shape. Details of these calculations are given concerning such things as: size of the problem and how to split it up, the number and shape of the finite elements, choosing the electrostatic potential correctly and selecting the potential of the desired pole.