Sensitivity analysis of the geometrical misalignments of X-ray computed tomography systems on dimensional measurements

X-ray computed tomography (XCT) is increasingly used in dimensional metrology. However, the accuracy enhancement of XCT-based measurements still represents a major challenge due to the large number of influence factors. This work focuses on the enhancements that are achievable by monitoring and correcting the system geometry, through the inspection of parameters describing the relative position and orientation between the hardware components. The work is part of a research project aiming at (i) achieving a complete understanding of the geometry-dependent effects on XCT measurement results and (ii) developing a fast and easy-to-implement procedure per the system geometry characterization and correction. At the scope, a simulation-based sensitivity analysis was designed to investigate the relationship between the deviation of geometrical parameters from the optimal/aligned configuration and the accuracy of dimensional measurements, with the aim of identifying the most critical parameters to be examined and corrected. The effect of each type of geometrical misalignment was tested separately. The study was carried out using a dedicated reference geometry, specifically designed for the purpose.