Electron trajectories in twisted electrostatic deflection yokes

A mathematical analysis is carried out for electron motion in a cylindrical electrostatic deflection yoke which is twisted around its axis and immersed in a uniform axial magnetic field to form a twisted focus projection and scanning (FPS) deflection system. The yoke has an arbitrary twist angle, and is a generalization of yokes with π/2 rad of twist recently used in FPS vidicons. New modes of operation are found which eliminate shading caused by off-normal beam landing at the target, while providing improved deflection sensitivity, increased resolution, and reduced power consumption in the focusing solenoid as compared with the untrusted shading-free mode previously reported by Schlesinger, Wagner, and Saldi [1]-[3]. The theoretical predictions are supported by data from experimental devices.