Dynamical effects in Bragg coherent x-ray diffraction imaging on finite crystals

摘要

We present simulations of Bragg Coherent X-ray Diffractive Imaging (CXDI)data from finite crystals in the frame of the dynamical theory of x-raydiffraction. The developed approach is based on numerical solution of modifiedTakagi-Taupin equations and can be applied for modeling of a broad range ofx-ray diffraction experiments with finite three-dimensional crystals ofarbitrary shape also in the presence of strain. We performed simulations fornanocrystals of a cubic and hemispherical shape of different sizes and provideda detailed analysis of artifacts in the Bragg CXDI reconstructions introducedby the dynamical diffraction. A convenient way to treat effects of refractionand absorption supported by analytical derivations is described. Our resultselucidate limitations for the kinematical approach in the Bragg CXDI andsuggest a natural criterion to distinguish between kinematical and dynamicalcases in coherent x-ray diffraction on a finite crystal.