Electron microscopy
 
Range of Energy Losses of Various EELS Signals
- Practical Electron Microscopy and Database -
- An Online Book -
Microanalysis | EM Book                                                                                   http://www.globalsino.com/EM/        

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Table 3166a lists the main characteristics (energy loss and scattering semiangle) of the four most common energy-loss processes when an incident electron beam is interacting with materials. However, in general, the intensities of all the energy-loss processes decrease with increase of scattering semiangles θ.

Table 3166a. Main characteristics of the four most common energy-loss processes.

Process
Energy loss (eV)
Scattering semiangle (mrads)
Phonon excitation
~0.03 5-40
Inter/intra-band transitions
5-25 5-10
Plasmon excitation
~5-30 <~0.1
Inner-shell ionization
~30-2000 1-20

For EELS measurements, inelastic scattering events with energy losses up to ~2 keV are experimentally intense enough to be useful.

Table 3166b. Properties of various EELS energy ranges.

Energy range Properties
~50 - 2000 eV K and L core loss edges corresponding to chondritic elements
284-532 eV Extremely favorable energy region, where C, N and O possess K-edges
> 500 eV Edge visibility is compromised due to the rapidly decaying spectrum intensity

 

 

 

 

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