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Contrast in the electron spectroscopic imaging mode of a TEM

1990; Wiley; Volume: 159; Issue: 2 Linguagem: Inglês

10.1111/j.1365-2818.1990.tb04772.x

1365-2818

L. Reimer, M. Roß‐Meßemer,

X-ray Spectroscopy and Fluorescence Analysis

SUMMARY The ratio of inelastic‐to‐elastic total cross‐sections has been measured in an energy‐filtering electron microscope for different elements. Formulae for the transmission of elastically and inelastically scattered electrons in part I were used to calculate the optimum conditions for a Z ‐ratio contrast in the electron spectroscopic imaging mode. Structure‐sensitive contrast can be observed for all non‐carbon atoms in biological sections when filtering with an energy loss at Δ E ∼ 250 eV below the carbon K edge. Model experiments with evaporated layers of different elements on a carbon film allow measurement of the contrast increase. Filtering with the carbon plasmon loss shows a lower phase contrast than with zero‐loss filtering. This can be explained by calculating contrast transfer functions for inelastically scattered electrons.