Phase-contrast X-ray imaging system with sub-mg/cm3 density resolution

We improved the mechanical stability of the optical components of a two-crystal X-ray interferometer used in a phase-contrast X-ray imaging system. A branch beamline was dedicated to the system to suppress the rotation caused by the thermal drift, and the feedback system for stabilizing the interferometer was renewed to speed up the feedback frequency. An interference pattern with 80% visibility was successfully generated using a 17.8-keV synchrotron X-ray. The mechanical stability of the optical components attained was 12 prad over 10 hours, and the rotational accuracy was less than 50 prad by using the new feedback systems. Fine observations of biomedical and organic material samples were successfully performed. We achieved a density resolution of the sectional image of about 0.3 mg/cm3.