Selected-area diffraction and spectroscopy in LEEM and PEEM

This paper addresses the effects of spherical and chromatic aberration of the objective lens, as well as chromatic dispersion of magnetic prism arrays, on the ability to perform selected area Low Energy Electron Diffraction, as well as (Angle Resolved) Photo Electron Spectroscopy experiments in today's advanced cathode lens microscopy instruments.

► Aberrations of the cathode lens affect SA diffraction and spectroscopy experiments in LEEM/PEEM.
► In LEEM the problem can be overcome by inserting the SA aperture in the illuminating path.
► In PEEM for selected areas smaller than 2–4 μm aberration correction becomes a necessity.
► Chromatic dispersion in the magnetic prism array commonly can be neglected in most cases.