pyDFXM: A Python simulator for dark-field X-ray microscopy (DFXM)

This is a Python simulator for dark-field X-ray microscopy (DFXM). It is based on the MATLAB implementation of the formulation in the Poulsen et al. (2021) paper and Poulsen et al. (2017) paper.

References:

1. H. F. Poulsen, A. C. Jakobsen, H. Simons, S. R. Ahl, P. K. Cook, and C. Detlefs, X-Ray Diffraction Microscopy Based on Refractive Optics, J Appl Crystallogr 50, 1441 (2017).
2. H. F. Poulsen, L. E. Dresselhaus-Marais, M. A. Carlsen, C. Detlefs, and G. Winther, Geometrical-Optics Formalism to Model Contrast in Dark-Field X-Ray Microscopy, J Appl Crystallogr 54, 1555 (2021).

Installation

The simulator requires the following Python packages:

• numpy (tested on 1.21)
• scipy (tested on 1.4)
• matplotlib (tested on 3.4.3)

Code structure

The code (Supplementary material of the Poulsen et al., 2021 paper) can be separated into three distinct parts:

• The resolution function (res_fxn_q)
• Displacement gradient of edge dislocation (edge_disl_helper)
• DFXM forward model (forward_model_setup)

We will test them separately in the following example cases and write necessary notes to help the users to better understand how to use and modify the code.

Example cases

The following example cases are provided:

• test_res_fn.py: Test and visualize the reciprocal-space resolution function of the simulator.
• test_forward_shear.py: Simulate the DFXM image of a simple shear stress field. One strain component is enforced in a sphere of radius R.
• test_dispgrad_edge.py: Simulate the DFXM image of a single straight edge dislocation.