The 127° Electrostatic Analyzer: Performance as a Spectrometer

Abstract

The basic design and performance characteristics of a 127° electrostatic analyzer are derived from an exact solution of the potential within a bounded two-dimensional cylindrical sector. The results are compared with those found from radial field theory, to show that transmission is nonsymmetric in both energy and incident angle about the 'tuning' and 'normal' values respectively. Except for normally incident particles the usual radial-field calibration equation cannot be relied upon unless the analyzer design is altered to minimize end aberrations. Modified beam entry conditions are given to optimize the performance of the analyzer.