An electron energy spectrometer of double-stage retarding field type, 1

Paraxial electron trajectories in a given retarding field has been numerically computed, from which the focusing properties as an electron energy analyzer are derived. However, this analyzer exhibits at least two pronounced peaks even for mono-energetic electrons. By applying the same treatment to a spectrometer of the double-stage retarding field type, expressions for the line profile and energy resolution have been obtained. In order to improve the double-peaking characteristic, it seems effective to impose slightly unbalanced retarding potentials. (auth.)