Dictionary Indexing of Electron Channeling Patterns.
The dictionary-based approach to the indexing of diffraction patterns is applied to electron channeling patterns (ECPs). The main ingredients of the dictionary method are introduced, including the generalized forward projector (GFP), the relevant detector model, and a scheme to uniformly sample orientation space using the "cubochoric" representation. The GFP is used to compute an ECP "master" pattern. Derivative free optimization algorithms, including the Nelder-Mead simplex and the bound optimization by quadratic approximation are used to determine the correct detector parameters and to refine the orientation obtained from the dictionary approach. The indexing method is applied to poly-silicon and shows excellent agreement with the calibrated values. Finally, it is shown that the method results in a mean disorientation error of 1.0° with 0.5° SD for a range of detector parameters.
Department of Materials Science and Engineering,Carnegie Mellon University,5000 Forbes Avenue,Pittsburgh,PA 15213,USA.
Saransh
S
Singh
Department of Materials Science and Engineering,Carnegie Mellon University,5000 Forbes Avenue,Pittsburgh,PA 15213,USA.
Marc
M
De Graef
ECP; dictionary matching; dynamical electron scattering; electron channeling pattern