Universal simulation of absorption effects for X-ray diffraction in reflection geometry.

Area of Science:

• Materials Science
• Crystallography
• Computational Physics

Background:

• X-ray powder diffraction (XPD) experiments require accurate absorption corrections, especially for non-ideal samples.
• Complex sample features like surface roughness, porosity, and multiphase composition necessitate sophisticated mathematical models.
• Existing models struggle to precisely represent the spatial distribution of materials and their impact on X-ray absorption.

Purpose of the Study:

• To develop a practicable computational method for simulating angle-dependent absorption corrections in X-ray powder diffraction.
• To create a versatile ray-tracing algorithm capable of handling diverse sample complexities, including surface roughness, porosity, and multiphase systems.
• To provide a detailed algorithmic framework and validate its performance against experimental data.

Main Methods:

• Formulation of a ray-tracing algorithm using a voxel grid to represent sample geometry and material properties.
• Implementation of a modified shear-warp algorithm to trace X-ray paths and calculate attenuation.
• Modeling of single and multiphase systems with arbitrary surface roughness and porosity distributions.

Main Results:

• Successful simulation of angle-dependent absorption corrections for rasterized sample models.
• Demonstration of the algorithm's capability to model complex sample features, including surface modulations and phase distribution.
• Validation of simulated results against published experimental data for non-ideal samples.

Conclusions:

• The developed ray-tracing algorithm offers a robust and adaptable solution for absorption corrections in X-ray powder diffraction.
• This computational approach enhances the accuracy of diffraction data analysis for challenging, non-ideal sample types.
• The method provides a valuable tool for researchers investigating materials with complex microstructures.