Electron microscopes

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Electron microscopes

Electron microscopes use electrons instead of light to form and images and they have a maximum resolution of 0.0001 micrometers, wiich is about 2000 times higher than light microscopes. There are two different types of electron microscopes.

Transmission electron microscores (TEM's)

  • They use electromagnets to focus a beam of electrons, which is then transmitted through the specimen.
  • Denser parts of the specimen absorb more electrons, which make them look darker on the image.
  • TEM's produce high resolution images but they can only be used on thin specimens.

Scanning electron microscopes (SEM's)

  • SEM's scan a beam of electrons across the specimen, this knocks off electrons from the specimen which are gathered in a cathode tube ray to form an image.
  • The image shows the surface of the specimen and they can be 3D.
  • SEM's can be used on thick spacimens but the give a lower resolution than TEM's.
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