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
- This is because the specimen is stained with a heavy metal
- 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
- Transition electron microscope
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