Utilization of STEM nanodiffraction data
| Autor: | John H. Konnert, Peter D'Antonio |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Conventional transmission electron microscope
Diffraction Microscope business.industry Chemistry Resolution (electron density) Scanning confocal electron microscopy Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials law.invention Optics law Scanning transmission electron microscopy Energy filtered transmission electron microscopy business Instrumentation Beam (structure) |
| Zdroj: | Ultramicroscopy. 38:169-179 |
| ISSN: | 0304-3991 |
| Popis: | A scanning transmission electron microscope (STEM) designed to simultaneously record all of the diffraction data at each beam position is necessary to fully utilize the imaging potential of a STEM. However, analysis of this large quantity of data requires considerable computation that should be undertaken only with the assurance that the data were collected under near optimum conditions from the desired region of the sample. This paper develops equations for the total elastic scattering produced with a small, coherent electron beam incident on a thin sample. These equations are used as the basis for simulations which indicate that high-angle annular-dark-field (ADF) images may be used to indicate the quality of the diffraction data. When the microscope is adjusted such that the portion of the data falling within a high-angle annulus forms a real-time high-resolution image with 2.5A˚resolution or better, the simultaneously recorded nanodiffraction data are suitable for the reconstruction of images possessing 1A˚resolution or better. While the resolution of the ADF image is determined by the electron beam size, the coherent nanodiffraction data contain structural information for each beam position to the resolution limit of the diffraction pattern. |
| Databáze: | OpenAIRE |
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