For quantitative simulation of characteristic x-ray or Auger electron intensities it is essential to have absolute ionization cross-section values. Although there is a lot of literature extensively dealing with measurements [Pow76] for and calculations of electron impact ionization cross sections, the large deviations between different ICS-measurements as well as the numerous models proposed by various authors show, that a satisfying solution of both measurement and calculation of inner-shell ionization cross-section has not yet been found.
In SESAME, a parameterization of a formula proposed by Hutchins [Hut74] published by Pouchou [Pou93] and a classically calculated expression by Gryzinski [Gry65] are implemented.
The formula by Pouchou is:
with and e is the Euler's constant. The parameters for
the K-shell is:
The parameters for the L-subshells and the M-subshells are:
The expression from Gryzinsky, mainly valid for K-shell ionization, is:
The differential cross section for inner shell ionization, which
describes the energy loss has also been proposed by
Gryzinsky:
Further information about inelastic scattering can be found in the
review papers of Ding [DS89] and Powell [Pow76] and
in the CEC--Vienna Report by Horst Wagner [Wag94]. A
detailed theoretical description of the inelastic scattering
processes may be found in the book of Schattschneider [Sch86].