Optimum angle of deflection electrodes of a cylindrical electrostatic analyzer

Abstract
The optimum deflection angle of the electrodes in a cylindrical electrostatic analyzer with real slits has been discussed on the basis of numerically calculated electron trajectories. The effect of fringing fields has been included exactly in this calculation. The optimum angle is 126.5°, being independent of the gap between the inner and outer electrodes. By this optimization, the first-order angle aberration can be eliminated completely.