Determination of the illuminating angle and defocus spread in transmission electron microscopy

Abstract
SUMMARY: In high resolution electron microscopy the beam divergence and defocus spread are important factors determining the resolution limit of the microscope. In this paper a straightforward method is proposed to estimate the illuminating angle (beam divergence) and the parameter of defocus spread using optical diffraction patterns from a through focal series of electron micrographs of a thin amorphous film.