Laboratory-based X-ray phase-contrast imaging with misaligned optical elements

Abstract

We report on a laboratory X-ray phase-contrast imaging technique based on the edge illumination principle that substantially relaxes the existing limitations on system set up and data acquisition, allowing an increase in tolerance of misalignments by at least two orders of magnitude. The robustness of this approach was systematically studied by means of experiments with our prototype. Numerical simulations were also performed in order to assess the dependence of the image quality on the data acquisition scheme. The results show that errors in the positioning of the masks within a 1° range for all the angles, and within 1 mm range of translation, do not noticeably affect image quality. We also show that, if the misalignment does not exceed few tens of micrometers, three intensity projections are sufficient to effectively retrieve the three representations of the sample, allowing for optimization of dose or time efficiency even with a non-ideal system.