Application of the X-ray tracing method to powder diffraction line profiles

An X-ray tracing program was developed to simulate the instrument function of a high-resolution X-ray powder diffractometer. The optics of this laboratory instrument consist of a conventional X-ray tube, a single flat Ge monochromator, slits, the powder sample and finally a curved position-sensitive detector. Such a setup provides an interesting case study in order to assess X-ray tracing, which has seldom been used in the case of laboratory equipment. The simulation reported in this paper covers different aspects of optics simulation, ranging from straightforward kinematic diffraction to dynamic diffraction by single crystals or learned detector response function. The comparison between the simulation and the profiles measured using the NIST line profile standard SRM 660a LaB6 shows a good agreement. This result provides the basis for discussing the opportunity of using X-ray tracing in diagram-retinement software.