Improved physics in SIMNRA 7

SIMNRA is an analytical code for the simulation of ion beam analysis energy spectra obtained by Rutherford backscattering, non-Rutherford scattering, elastic recoil detection analysis, and nuclear reaction analysis. Improvements of the simulation physics in SIMNRA version 7 include among others the skewness of all energy spread distributions, improved handling of scattering or reaction cross-sections with structure, generalized layer roughness, and sample porosity.