Electron microscopy
 
Descan of Electron Beam in (S)TEM
- Practical Electron Microscopy and Database -
- An Online Book -
Microanalysis | EM Book                                                                                   http://www.globalsino.com/EM/        

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Figure 1765 shows the schematic illustration of a STEM spectrum imaging system. The focused electron probe is scanned across the specimen and a couple of post-specimen coils is used to descan.

Schematic illustration of a STEM spectrum imaging system together with a specially designed spectrometer that has an electrostatic shutter

Figure 1765. Schematic illustration of a STEM spectrum imaging system.

In the technique of precession electron diffraction (PED), to obtain a stationary diffraction pattern instead of ring reflections, a simultaneous descan of the diffracted beam is also needed by means of image shift TEM coils.

 

 

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