Reduction of energy non-linearity of hemispherical deflection analyzers when used with multidetectors

A “3-dimensional” computational study has been carried out on the energy non-linearity of a hemispherical deflection analyzer (HDA) used in conjunction with a multidetector. It is found that the energy non-linearity can be minimised by keeping the multidetector and its mounting at a single potential and not attempting to correct the fringing field to reproduce the field of the “perfect” HDA. The values of energy aberrations and the position of the focal plane are computed for a range of values of the ratio of the radii of the two hemispheres.