Electron Microscopes

Description of functions of Transition and Scanning electron microscopes.

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  • Created by: Joanna S
  • Created on: 18-09-13 21:45
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  • Electron Microscopes
    • Transition electron microscope
      • TEM
      • Electrons pass through the sample depending on the density
        • Like in an X-Ray
        • The sample has to be specially prepared and this takes a lot of skill and practise
        • Electrons pass through denser parts of the sample less easily which provides contrast
      • x500 000
      • 2D images
    • Scanning electron microscope
      • SEM
      • The electron beam is directed onto a sample and bounces off
        • The beam doesn't pass through
      • 3D images
      • x100 000
    • Magnification = Size of image / Actual Size
    • The specimen has to be dead in order to be viewed
      • This is because the specimen is stained with a heavy metal
        • This is usually osmium or lead
    • Magnets are used to focus the beam of electrons
    • The maximum resolution is 0.2 nm
    • Projected onto paper
      • This paper is called micrograph
    • These microscopes are really expensive and take up a lot of space
      • They usually cost a few million pounds


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