Applications of a post-column imaging filter in biology and materials science.

We have developed an energy-selecting imaging filter which can be attached to most transmission electron microscopes, and is capable of operating at primary energies of up to 400 keV. We review the filter's design and operation, and illustrate them with several applications including imaging of thick biological materials, energy-filtered diffraction, energy-filtered high-resolution imaging, and elemental mapping. We conclude the paper with a discussion of the areas of transmission electron microscopy in which the filter is likely to make especially significant contributions.