NSLS-II Seminar

Modern focusing optics is able to deliver x-ray beams of the size of 100 nm and smaller for a variety of applications based on scattering and diffraction techniques. Meanwhile, diffraction of focused beams from crystals requires detail theoretical and experimental analysis. Theory predicts that a focused x-ray beam Bragg diffracted from a perfect crystal has a fine structure which depends on the size of the beam, thickness of the crystal and diffraction conditions. In this talk, I will present first experimental results allowing for a detailed comparison with theory and outline possible practical applications.
Experiments were performed at the APS and the ESRF by using zone plates and refractive lenses as focusing optics. New experimental setup in which high-resolution detector is placed in the focus and crystal is positioned between the focusing optics and the focus was proposed and utilized. The broadening of the focused beam by crystals due to extinction effect and the evolution of fine spatial structure with angle were experimentally observed and analyzed. Experimental images recorded from real crystals and semiconductor structures demonstrate that this experimental setup can be used as a new imaging technique that combines spatial locality and depth sensitivity.