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Range of Validity - Restrictions

  The energy range of primary electrons, for which the hybrid model is valid, is equal to the one of the single scattering model (approximately between 1 and 50 keV). Also the appropriate overvoltage range for the simulation of x-radiation corresponds to the single scattering model (approximately between 1 and 30).

The main differences between the hybrid model and the single scattering model are:

  1. The hybrid model calculates actual inner shell ionizations at a well defined locations, at which the ionizations take place in the sample. In contrast to the single scattering model, in which just the probability of an inner shell ionization is calculated, the hybrid model calculates the actual, discreet number of ionizations of the investigated shell.
  2. The hybrid model allows the user to simulate high energy secondary electrons. This is possible, because of the energy loss calculation after an inner shell ionization is using random numbers to get the new properties of the primary and secondary electron. Therefore the energy and the direction of the primary and the secondary electron are known. Due to the inaccuracy of the ionization cross section, only secondary electrons, which have been generated by inner shell ionizations, can be simulated.


Horst Wagner
Tue Mar 19 10:24:55 MET 1996