Forward Modeling Neutron Diffraction Intensity on HIDRA with Sinpol

We extend Sinpol, originally a single-crystal-to-polycrystal neutron transmission simulator for textured and strained materials into a forward-modeling framework that predicts pixel-resolved diffraction intensity for the High Intensity Diffractometer for Residual Stress Analysis (HIDRA) at the High Flux Isotope Reactor. The upgraded method computes coherent elastic scattering cross sections for grains sampled from user-defined orientation, grain-size, and strain distributions. It then projects scattered intensity onto HIDRA’s detector geometry and integrates over the instrument-defined gauge volume to produce detector-level diffraction patterns directly comparable with experiment. We simulate diffraction intensity for multiple grain-size distributions and systematically model strain effects on HIDRA peaks, reproducing peak shifts, anisotropic broadening, and line-shape evolution. These results provide quantitative links between microstructure and instrument response. By combining texture-aware scattering physics with realistic detector projection and attenuation, the framework enables predictive, high-throughput residual stress analysis in complex engineering components, supports experiment design and optimization, and accelerates data interpretation through forward comparisons and sensitivity studies. Overall, the HIDRA-focused capability strengthens the connection between microstructure, processing, and measured diffraction signals.

This research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by Oak Ridge National Laboratory.