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Improving the Electron Microscope

Improving the Electron Microscope. So we can see just a few more nanometers. Electron Optics. Based on the principles of DeBroglie Electrons and other particles have wave properties Magnetic fields are analogous to optical lenses. Basics of Electron Microscopy.

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Improving the Electron Microscope

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  1. Improving the Electron Microscope So we can see just a few more nanometers

  2. Electron Optics • Based on the principles of DeBroglie • Electrons and other particles have wave properties • Magnetic fields are analogous to optical lenses

  3. Basics of Electron Microscopy

  4. Types of Electron Microscopes • Scanning Electron Microscope (SEM) • Tunneling Electron Microscope (TEM) • Scanning Transmission Electron Microscope (STEM)

  5. Limitations • Target sample must be modified to maintain in a high vacuum • Target sample must be conductive. • Electron Scattering

  6. Causes of Poor Resolution • General Electron Diffraction • Electro-Optical Aberrations

  7. Fixing Diffraction • Quite simple… • It actually doesn’t need a whole slide to explain.

  8. Scherzer ‘s Theory • Non trivial • Scherzer’s Theory states that aberration will always occur if the following conditions are met: • (i) There is a rotationally symmetrical lens present • (ii) The beam is acted upon by a static field • (iii) The beam does not reverse its velocity

  9. Correcting Electro-Optical Aberrations • 1995 Researchers Have worked on Breaking symmetry on lenses. • Resolution improved from 20nm to about 6nm by 1995 • Today We can achieve about .075nm resolution

  10. Correcting Electro-Optical Aberrations

  11. Correcting Electro-Optical Aberrations • Time varying Fields • Very complicated dealing with complex analysis • As of now, no one has been able to decrease aberration by implementing a time varying field

  12. Ende’

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