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The TEM and its Optics

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Abstract

The transmission electron microscope (TEM) has become the premier tool for the microstructural characterization of materials. In practice, the diffraction patterns measured by x-ray methods are more quantitative than electron diffraction patterns, but electrons have an important advantage over x-rays; electrons can be focused easily. By focusing the electron beam, diffraction patterns as discussed in Chapter 1 can be measured from microscopic regions, and it is often possible to select a single microcrystal for a diffraction measurement. The optics of electron microscopes can be used to make images of the electron intensity emerging from the sample. For example, variations in the intensity of electron diffraction across a thin specimen, called “diffraction contrast,” is useful for making images of defects such as dislocations, interfaces, and second phase particles. Beyond diffraction contrast microscopy, which measures the intensity of diffracted waves, in “high-resolution” transmission electron microscopy (HRTEM or HREM) the phase of the diffracted electron wave is preserved and interferes constructively or destructively with the phase of the transmitted wave. This technique of “phase-contrast imaging” is used to form images of columns of atoms. High-resolution images of atom columns are also possible with electron nanobeams incident on the sample, and electron scattering at high angles to minimize electron interference behavior (a method called “high-angle annular dark-field imaging”).

Keywords

Optic Axis Objective Lens Select Area Diffraction Select Area Diffraction Pattern Spherical Aberration 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Further Reading

  1. M. De Graef: Introduction to Conventional Transmission Electron Microscopy (University Press, Cambridge 2003).Google Scholar
  2. J. W. Edington: Practical Electron Microscopy in Materials Science, 1. The Operation and Calibration of the Electron Microscope (Philips Technical Library, Eindhoven 1974).Google Scholar
  3. P. J. Goodhews and F. J. Humphreys: Electron Microscopy and Microanalysis (Taylor & Francis Ltd., London 1988).Google Scholar
  4. P. Grivet: Electron Optics, revised by A. Septier, translated by P. W. Hawkes (Pergamon, Oxford 1965).Google Scholar
  5. P. B. Hirsch, A. Howie, R. B. Nicholson, D. W. Pashley, and M. J. Whelan: Electron Microscopy of Thin Crystals (R. E. Krieger, Malabar, Florida 1977).Google Scholar
  6. D. C. Joy, A. D. Romig, Jr. and J. I. Goldstein, Eds.: Principles of Analytical Electron Microscopy (Plenum Press, New York 1986).Google Scholar
  7. R. J. Keyse, A. J. Garratt-Reed, P. J. Goodhew and G. W. Lorimer: Introduction to Scanning Transmission Electron Microscopy (Springer BIOS Scientific Publishers Ltd., New York 1998).Google Scholar
  8. M. H. Lorretto: Electron Beam Analysis of Materials (Chapman and Hall, London 1984).Google Scholar
  9. L. Reimer: Transmission Electron Microscopy: Physics of Image Formation and Microanalysis, 4th Ed. (Springer-Verlag, New York 1997).Google Scholar
  10. F. G. Smith and J. H. Thomson: Optics, 2nd Ed. (John Wiley & Sons, New York 1988).Google Scholar
  11. G. Thomas and M. J. Goringe: Transmission Electron Microscopy of Materials (Wiley-Interscience, New York 1979).Google Scholar
  12. D. B. Williams and C. B. Carter: Transmission Electron Microscopy: A Textbook for Materials Science (Plenum Press, New York 1996).Google Scholar

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© Springer-Verlag Berlin Heidelberg 2008

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