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Zero‐loss energy‐filtered imaging of frozen‐hydrated proteins: model calculations and implications for future developments
Author(s) -
Schröder R. R.
Publication year - 1992
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.1365-2818.1992.tb01537.x
Subject(s) - monte carlo method , resolution (logic) , electron diffraction , electron , diffraction , electron scattering , computational physics , scattering , range (aeronautics) , work (physics) , acceleration voltage , materials science , transmission electron microscopy , energy (signal processing) , optics , molecular physics , physics , atomic physics , cathode ray , computer science , nuclear physics , thermodynamics , statistics , mathematics , quantum mechanics , artificial intelligence , composite material
SUMMARY Energy‐filtered transmission electron microscopes operating in zero‐loss mode are used increasingly to study biological material in frozen‐hydrated conditions. The contrast enhancement and improved structural resolution obtainable by this method have been studied using Monte‐Carlo model calculations for the scattering processes occurring in such samples. Three models representing typical situations have been analysed, each normalized to minimal beam damage. It is shown that for proteins in thin layers of ice an optimal signal‐to‐noise ratio is achieved in the 80–120‐keV electron energy range. For proteins which have to be embedded in thicker ice layers, a considerably higher acceleration voltage is required. In particular, electron energies above 200 keV would be desirable for electron diffraction work on microcrystals.