Dynamical Electron Backscatter Diffraction Patterns. Part I: Pattern Simulations

Abstract

A new approach for the simulation of dynamic electron backscatter diffraction (EBSD) patterns is introduced. The computational approach merges deterministic dynamic electron-scattering computations based on Bloch waves with a stochastic Monte Carlo (MC) simulation of the energy, depth, and directional distributions of the backscattered electrons (BSEs). An efficient numerical scheme is introduced, based on a modified Lambert projection, for the computation of the scintillator electron count as a function of the position and orientation of the EBSD detector; the approach allows for the rapid computation of an individual EBSD pattern by bi-linear interpolation of a master EBSD pattern. The master pattern stores the BSE yield as a function of the electron exit direction and exit energy and is used along with weight factors extracted from the MC simulation to obtain energy-weighted simulated EBSD patterns. Example simulations for nickel yield realistic patterns and energy-dependent trends in pattern blurring versus filter window energies are in agreement with experimental energy-filtered EBSD observations reported in the literature.

Point-group sensitive orientation mapping of non-centrosymmetric crystals

“…6,7 Because of the increased information content which is provided by dynamical electron diffraction in EBSD Kikuchi patterns, the detailed simulation and analysis of the respective effects is becoming more and more important. 8 Typical applications include EBSD-based lattice strain analysis, 9 EBSD image segmentation, 10,11 and the analysis of orientation relationships in phase transformations. 12 Moreover, EBSD-based chirality determination was recently demonstrated.…”

EBSD image segmentation using a physics-based forward model

“…The quality of this model is demonstrated in [10], where it produces simulated patterns close to experimental patterns. For each orientation, the process consists of three steps.…”

Automated Acquisition and Analysis of Selected Area Electron Channeling Patterns in an FEG-SEM

“…Because of the potentially small size of this selected area, local changes to the lattice parameters can be identified by observing changes in the positions of HOLZ lines. Prior work has established a dictionary-based mapping technique for SACPs, which is used to identify an orientation for any given SACP based on the imaging parameters as well as the sample structure and composition [1].Dictionary indexing of SACPs is accomplished by simulating patterns for all possible Euler angle combinations, with some finite step size in orientation space, and taking the dot product of experimental and simulated patterns [2]. The maximum value of this dot product is then taken to be the best fit for the experimental pattern.…”

“…Dictionary indexing of SACPs is accomplished by simulating patterns for all possible Euler angle combinations, with some finite step size in orientation space, and taking the dot product of experimental and simulated patterns [2]. The maximum value of this dot product is then taken to be the best fit for the experimental pattern.…”