Forschung

This study presents the implementation of a novel data analysis methodology to perform spatially resolved crystallographic texture analyses in bulk specimens at POLDI, the pulsed frame overlap diffractometer at SINQ, Paul Scherrer Institute. The method is based on the determination of several incomplete pole figures. To increase the angular resolution, the POLDI diffraction bank is split into several virtual units of smaller angular coverage. The diffraction data of each virtual unit can then be analyzed individually and used to create experimental pole figures from the Euler angles of the explored sample orientations. Additionally, to help the analyses, a new numerical tool was developed and implemented at POLDI to calculate neutron flight path of each virtual detector as a function of sample size, geometry, and orientation. Leveraging on the SALOME platform’s Geom module (open-source CAD modeler), the tool allows inserting CAD objects into a virtual detailed PODI geometry. This allows to automate sample positioning and orientation within the instrument frame and computes flight path intersections. It serves two main purposes: enhancing texture analysis through precise path calculations and aiding experimental design by visually evaluating orientation feasibility and estimating counting times. Finally, to complete the analysis path from the experiments to the results, the experimental and numerical evaluations are processed together with POLTex (MATLAB-based toolbox) to obtain the orientation distribution functions. To demonstrate the analysis routine, the crystallographic texture of an additively manufactured steel sample and Zircaloy-4 sample were characterized.