Propagation-based x-ray phase imaging using focusing polycapillary optics

Conventional x-ray imaging relies on differences in attenuation in a material to produce image contrast. While useful for differentiating structures with large density variations, the subtle differences in attenuation for low-density materials can be difficult to detect. X-ray phase imaging, on the other hand, relies on differences in phase delay which is typically several orders of magnitude larger than attenuation. However, most methods of producing x-ray phase images rely on specialized synchrotron sources, small and low power microfocus sources or the careful alignment of several precision gratings. We demonstrate that focusing polycapillary optics can produce small focal spots from conventional x-ray sources to enable phase imaging. Moreover, in conjunction with focusing optics, the use of a simple, low cost wire mesh to structure the beam can significantly improve phase reconstructions.