Amplification of the phase contrast signal at very high x-ray energies.

X-ray phase contrast imaging is increasingly being used in several fields, both at synchrotron facilities and with laboratory sources, due to its increased sensitivity compared to conventional x-ray methods. One important problem is the development of methods to make it suitable for use at very high x-ray energies, needed in many applications. We show how the edge illumination concept, which stands at the basis of the coded-aperture method, allows achieving hyperintense phase signals at energies close to 100 keV, by showing images of both weak phase objects and highly absorbing fossils with a high iron content.