Contrast by electron microscopy in thick biological specimens.

ABSTRACT: The contributions of coherent bright-field phase and incoherent dark-field amplitude contrast are investigated for thick biological specimens. A model for a T4 phage is constructed and images simulated for both TEM and STEM phase contrast using a multislice code. For TEM, the fraction of the illumination intensity available for phase contrast imaging is limited by the fraction of electrons in the zero loss peak, the plasmon peak, or the Landau distribution peak for very thick specimens. These were measured from electron energy loss spectra recorded from various thicknesses of vitreous ice. The incoherent amplitude contrast is simulated using the Penelope Monte Carlo code. Noise limits the features that can be distinguished under the low-dose conditions required for cryo-EM, even for high e

SUBMITTER: Rez P 

PROVIDER: S-EPMC12637017 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature