Minimum Image Size in a Parallel Plate Electrostatic Spectrograph

Abstract

Previous analysis of the focusing properties of a parallel plate electrostatic spectrograph has shown that second order focusing can be achieved. In the present paper it is demonstrated that as a corollary, there exists an optimum focal line in which the angular aberrations are reduced to one quarter of their values on the normal focal line, as is the case in optical systems. Results of computations of the line shapes are also presented.