E×B Mass-Separator Design

Abstract

The equations of motion are developed and solved for ion trajectories inside an E×B type mass separator. Curves are presented which illustrate the focusing of the undeflected ion beam, the trajectories along which ions of different mass species disperse inside the separator channel, and the exit slopes of mass species leaving the separator, as functions of a separator strength parameter. For strong separators, beam focusing is significant and is shown to be nonaxisymmetric when the electric and magnetic fields are uniform and orthogonal. A method of correcting the astigmatism by tilting the magnetic pole pieces is presented.