Double Focusing of Charged Particles by a System of Two Magnets with Nonuniform Fields

Abstract

Equations are obtained for the focusing by a system of two magnets with nonuniform fields such that n>0 in the first magnet and nn, there is in general one object distance for which double focusing takes place. The theory is also applied to deflecting systems with moderate values of n, and it is shown that the entrance and exit angles can be reduced to values of the order of 20° even for small deflections (20°) of the charged particle.