X-Ray Interferometry at ESRF Using Two Coherent Beams from Fresnel Mirrors.

Using two small flat mirrors under grazing incidence, we have produced interference patterns from partially coherent x-ray beams at the European Synchrotron Radiation Facility. By piezoelectrically orienting one mirror around the horizontal plane, both the vertical and horizontal transverse coherence distances of the radiation have been measured. The experimental setup can be used to characterize the coherence properties along x-ray synchrotron beamlines.