Instrument Function of a Cylindrical Electron Energy Analyzer

Abstract

The instrument function describing the broadening of the spectral lines due to the energy analyzer is treated as the convolution product of the calculated partial energy distributions arising from the angular divergence, the widths of the slits, and the nonradial motion of the electrons. The cases of first order focusing, second order focusing, and minimum trace width are considered. The nonradial motion of electrons in the electric field caused by emission from outside the symmetry axis is calculated numerically without making approximations in the analytical expressions. The analysis leads to results different from those published earlier. The calculations show that combinations of electron optical parameters can be found for which the effect of nonradial motion is very small. When these combinations of parameters are used, the electron source can be made comparatively large in the transverse direction.