Edge illumination X-ray multi-contrast imaging without mask displacement

The Edge illumination (EI) multi-contrast imaging technique has emerged as a research focus in the fields of X-ray imaging due to its capability of simultaneously retrieving absorption, phase, and scattering images. For the classical EI method, it is essential to displace the mask in a direction perpendicular to the slits with submicron-level accuracy to obtain multiple images from which contrast information can be derived. However, this mask displacement not only adds to the complexity of the motion-control subsystems (which could also be a possible source of mechanical instability) but also increases the overhead time required for mechanical displacement, thus limiting the optimal imaging efficiency. In this study, we propose an EI imaging method that relies on electromagnetic focus displacement (EI-EFD) rather than mechanical mask displacement. Through detailed analysis, it is demonstrated that the X-ray focus displacement and the mask displacement are equivalent for sampling the illumination curve for each detector pixel under certain reasonable conditions. By utilizing an X-ray tube source with its focus position controlled by an external electromagnetic field produced by a homemade solenoid coil, we successfully captured multi-contrast images of a frozen hairtail, a pen, and a plastic rod. We believe that this proposed method will enhance the practicality of EI systems and facilitate their broader application.