TEMStrain    

Strain

The package can be seen as a tool for the determination of lattice parameters. However, due to the ambiguity problem (the same pattern can be simulated with different lattice parameters) it is more convenient to see this as a determination of small deviations from reference lattice parameters. Such deviations are formally described by the strain tensor. This representation has the advantage of straightforward manipulation between different coordinate systems. All components of the tensor can be determined if multiple patterns are used, and it is easy to get the lattice parameters from the tensor. In case of a single pattern, only certain components of strain tensor in a specific coordinate systems can be determined, and there is no unique solution in term of the lattice parameters. The package provides three different ways of analysing patterns. One is suitable for a single pattern. The other two are applicable to multiple patterns; one approach is to calculate specified strain components in the crystal coordinate system, and - in the other one - plane stress in the foil is assumed.