Design and realization of a coded-aperture based X-ray phase contrast imaging for homeland security applications

X-ray phase contrast imaging solves the basic problem of conventional X-ray imaging, i.e. low image contrast arising from small absorption differences. For years X-ray phase contrast imaging was thought to be restricted to synchrotron radiation facilities, but a new approach was recently developed at UCL which makes synchrotron-like phase effects achievable with conventional sources, by introducing two separate sets of appropriately designed coded-apertures at either side of the imaged object. gh most proposed applications of X-ray phase contrast imaging are focused on medical aspects, substantial advantages can be gained in other fields, including security inspections. In this case the system has to be based around higher X-ray energies, which has an impact on the system design. This paper describes such a design. A previously developed and experimentally validated simulation program was used to estimate the image contrast that can be expected from a range of details of interest in security inspections imaged under various conditions, including beam spectrum, detector characteristics, coded-aperture design, source-to-sample and sample-to-detector distances, etc.—while taking into account the interplay between these different parameters. The conditions providing maximum image contrast were chosen and used in the ultimate system design.