Problem of x-ray synchrotron beam collimation by zone plate

We present the first results of collimating the synchrotron radiation beam by zone plate located at the long distance from the source. Zone plate (ZP) has been fabricated from silicon crystal. We observe the interference fringes due to existence of various orders of focusing. We record experimentally an amplification of synchrotron beam intensity up to four times by means of ZP. The experimental measurements have been performed at the beam line BM-5 of the European Synchrotron Radiation Facility (ESRF) for the energy interval from 8 to 17.5 keV. The fringes were discussed on the base of analytical theory as well as were studied by means of computer simulation. The radial distribution of intensity is determined as a convolution of the zone plate transmission function and the Kirchhoff propagator in paraxial approximation.