Electron microscopy
 
EELS Spatial Resolution Depending on Specimen Thickness
- Practical Electron Microscopy and Database -
- An Online Book -
Microanalysis | EM Book                                                                                   http://www.globalsino.com/EM/        


=================================================================================

 

The spatial resolution of the EELS measurement in STEM mode can be estimated by the diameter of the probe irradiation on the specimen. Assuming the thickness of the specimen is t, then the spatial resolution is given by (see Figure 1307a):
          Spatial Resolution due to Specimen Drift -------------------------------- [1307]
where,
          α -- The convergence semiangle.

Diameter of the probe irradiation with specimen thickness t

Figure 1307a. Diameter of the probe irradiation with specimen thickness t.

For instance, Figure 1307b shows the spatial resolutions at convergence semiangles 7 and 15 mrad, respectively, based on Equation 1307. Note that such convergence semiangles are used in many TEM systems.

Examples of drift effect on spatial resolution
Figure 1307b. Spatial resolutions at convergence semiangles 7 and 15 mrad, respectively, based on Equation 1307.

 

 

=================================================================================