Beam tracking approach for single–shot retrieval of absorption, refraction, and dark–field signals with laboratory x–ray sources

We present the translation of the beam tracking approach for x–ray phase–contrast and dark–field imaging, recently demonstrated using synchrotron radiation, to a laboratory setup. A single absorbing mask is used before the sample, and a local Gaussian interpolation of the beam at the detector is used to extract absorption, refraction, and dark–field signals from a single exposure of the sample. Multiple exposures can be acquired when high resolution is needed, as shown here. A theoretical analysis of the effect of polychromaticity on the retrieved signals, and of the artifacts this might cause when existing retrieval methods are used, is also discussed.