Asymmetrically cut crystals as optical elements for coherent synchrotron radiation conditioning

Abstract

ABSTRACT Perfect crystals with asymmetric surface cut were studied to evaluate their influence on the coherence of x-rays. An analysis of single- and double-crystal setups in both Bragg and Laue geometries is presented. The Bragg case was studied experimentally. The experiments were performed at Optics Beamline BM5 of the European Synchrotron Radiation Facility.A virtual source created by an asymmetric crystal was probed using an interferometry technique based on fringe analysis,which were produced by boron fiber. The conditions required to preserve coherence in a double-crystal setup are obtainedtheoretically, and proved experimentally in case of Bragg diffraction.Keywords: asymmetric crystal, x-ray diffraction, spatial coherence, synchrotron radiation. 1. INTRODUCTION High degree of coherence of x-ray radiation is an exceptional feature of the synchrotron facilities of third generation. Thisgave rise to development of new techniques like phase contrast topography, holography, and tomography. Until now an