title: Hard X-ray nanofocusing at low-emittance synchrotron radiation sources.
abstract: X-ray scanning microscopy relies on intensive nanobeams generated by imaging a highly brilliant synchrotron radiation source onto the sample with a nanofocusing X-ray optic. Here, using a Gaussian model for the central cone of an undulator source, the nanobeam generated by refractive X-ray lenses is modeled in terms of size, flux and coherence. The beam properties are expressed in terms of the emittances of the storage ring and the lateral sizes of the electron beam. Optimal source parameters are calculated to obtain efficient and diffraction-limited nanofocusing. With decreasing emittance, the usable fraction of the beam for diffraction-limited nanofocusing experiments can be increased by more than two orders of magnitude compared with modern storage ring sources. For a diffraction-limited storage ring, nearly the whole beam can be focused, making these sources highly attractive for X-ray scanning microscopy.
authors.affiliation: Institut für Strukturphysik, Technische Universität Dresden, 01062 Dresden, Germany.
authors.forename: Christian G
authors.initials: CG
authors.lastname: Schroer
authors.affiliation: Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Falkenberg
keywords: X-ray nanofocus; X-ray optics; diffraction-limited storage ring