Phase objects in synchrotron radiation hard x-ray imaging

TLDR

Phase objects are easily imaged by Fresnel diffraction in hard X‑ray beams from third‑generation synchrotron sources because of their very small angular size, yet they can also produce spurious contrast in crystal topographs. The study aims to eliminate this spurious contrast by employing random phase plates to tailor the source angular size. The authors use random phase plates to adjust the source size and experimentally investigate this simple technique for imaging phase objects in hard X‑ray beams. The method proves promising, as shown on a human vertebra sample, and may be extended to phase tomography.

Abstract

Phase objects are readily imaged through Fresnel diffraction in the hard x-ray beams of third-generation synchrotron radiation sources such as the ESRF, due essentially to the very small angular size of the source. Phase objects can lead to spurious contrast in x-ray diffraction images (topographs) of crystals. It is shown that this contrast can be eliminated through random phase plates, which provide an effective way of tailoring the angular size of the source. The possibilities of this very simple technique for imaging phase objects in the hard x-ray range are explored experimentally and discussed. They appear very promising, as shown in particular by the example of a piece of human vertebra, and could be extended to phase tomography.