Premium
Simulation of atomic image profiles in dark field electron microscopy
Author(s) -
Korn Alex P.
Publication year - 1984
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1984.tb00539.x
Subject(s) - optics , dark field microscopy , tilt (camera) , aperture (computer memory) , physics , lens (geology) , beam (structure) , scattering , resolution (logic) , microscopy , geometry , artificial intelligence , computer science , mathematics , acoustics
SUMMARY One‐dimensional atomic image profiles have been calculated for the fixed beam dark field mode of electron microscopy. They were generated by applying the lens‐related phase shifts to the complex electron‐atom scattering amplitude function for mercury. The dark field geometries simulated were beam stop, aperture shift, beam tilt and combination beam tilt‐aperture shift. It was shown that the correct defocus is 20–30 nm. However, using an aperture incompatible with the resolution limit dictated by the lens related phase shift function leads to an apparent optimum defocus that, while yielding maximum intensity and sharpness, increases the chance of interference artefacts. Provided that a compatible aperture is used, dark field in a beam tilt geometry does not create severe asymmetries in the profile nor a change in the resolution as compared to the beam stop method.