Long trace profiler downward- and sideways-facing measurement simulations

Maintaining optimal x-ray beam quality in accelerator-based light-sources requires mirrors with exceptional shape and surface precision. In practice, mirrors are often mounted in diverse orientations—such as in Kirkpatrick–Baez systems—where gravitational and mechanical effects may differ significantly from upward-facing metrology configurations. In this study, we use optical ray tracing to investigate alternative metrology geometries suitable for measuring side-facing and downward-facing mirrors. We propose a modified profilometry approach for use with the European Synchrotron Radiation Facility long trace profiler, in which beam folding optics are integrated beneath the scanning head to redirect the measurement beam. The approach combines a detailed optical model of the instrument implemented using ray-tracing, enabling accurate evaluation of the impact of motion-induced errors under realistic acquisition conditions. For downward-facing configurations, a promising solution was found experimentally, then characterized, and investigated with an analysis of the impact of alignment tolerance. While preliminary insights are provided for the side-facing setup, all proposed configurations exhibited sensitivity to motion errors of the scanning head, highlighting challenges for robust implementation.