Computer simulations are utilized to show how to use a transmission electron microscope which has an objective lens with an adjustable coefficient of spherical aberration to determine the three spatial coordinates of a single heavy atom embedded in a crystal. This information can be obtained by forming an image with only those electrons that have been scattered through a large angle by the crystal. By using a high-angle annular dark-field aperture the atoms can be considered as independent scatterers, in contrast with imaging with low-angle coherent scattering. In addition, by reducing the aberration coefficients of the lens, the effective outer radius of the aperture can be made large, thereby leading to a small depth of focus. Calculations show that this form of imaging produces detectable contrast with currently available aberration correctors, sources and detectors. [References: 24]
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