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

## TL;DR

This paper develops a numerical simulation approach based on dynamical diffraction theory to analyze artifacts in Bragg CXDI reconstructions of finite crystals, highlighting limitations of the kinematical approximation.

## Contribution

It introduces a dynamical theory-based simulation method for Bragg CXDI of finite crystals, accounting for strain, shape, and artifacts, advancing understanding of diffraction effects.

## Key findings

- Dynamical effects cause artifacts in Bragg CXDI reconstructions.
- The developed model can simulate diffraction for arbitrary crystal shapes.
- A criterion to distinguish between kinematical and dynamical regimes is proposed.

## Abstract

We present simulations of Bragg Coherent X-ray Diffractive Imaging (CXDI) data from finite crystals in the frame of the dynamical theory of x-ray diffraction. The developed approach is based on numerical solution of modified Takagi-Taupin equations and can be applied for modeling of a broad range of x-ray diffraction experiments with finite three-dimensional crystals of arbitrary shape also in the presence of strain. We performed simulations for nanocrystals of a cubic and hemispherical shape of different sizes and provided a detailed analysis of artifacts in the Bragg CXDI reconstructions introduced by the dynamical diffraction. A convenient way to treat effects of refraction and absorption supported by analytical derivations is described. Our results elucidate limitations for the kinematical approach in the Bragg CXDI and suggest a natural criterion to distinguish between kinematical and dynamical cases in coherent x-ray diffraction on a finite crystal.