Electron Interference: Scanning Electron Microscope

[cragar]

When a scanning electron microscope shoots electrons at the material they wish to observe ,
when the secondary electrons are ejected from the material and then received at the detector
it seems like electron diffraction might affect the image , But it doesn't seem to , or maybe they got around this some how , ?

 

[AJ Bentley]

A scanning electron microscope (SEM) produces an image from electrons that are ejected from the very top atomic layer of the sample. The penetration depth is virtually zero.

Diffraction requires the electrons to travel many lattice units through the sample.

In fact, diffraction studies are normally only performed using a Transmission Electron Microscope (TEM) where the primary beam travels right through and out the other side.

 

[cragar]

what about a reflection grating ,

 

[AJ Bentley]

The electrons don't 'reflect'. It's an inelastic collision with the production of secondary electrons. Phase information is lost

 

[cragar]

ok so why can't the secondary electrons interfere with each other on their way to the detector and produce an interference pattern