Characterization of the in-line x-ray phase contrast imaging beam line developed at ALLS and based on laser driven betatron radiation

The 200TW ALLS laser system (30 fs, 5J) is used to accelerate electrons through laser wakefield and generate betatron emission in the 10keV range. Single shot phase contrast images of a series of nylon fibers with diameter ranging from 10μm to 400μm have been obtained in different geometries and are interpreted with a comprehensive model of x-ray propagation integrating the properties and geometries of the imaging beam line. A simple figure of merit, which can give indication on the interface sharpness of a phase object, is used to assess the quality of the imaging beam line.