Application of immersion objective lens aberration properties for secondary electrons energy analysis

The results of numerical simulation and experimental study show that in the field of vision of an electrostatic immersion objective there exist three regions: the region of paraxial electrons, the region of peripheral electrons and the transition region. They differ in electron optical characteristics. The abnormal high coefficient of spherochromatic aberration in the transition region allows the immersion objective to be used as an input energy filter in the energy analyser with retarding field, the slope of S-curve being increased by a factor of 4–5. The implementation of energy analysers requires additional feedbacks to control the immersion objective electrodes.