title: Bent perfect crystals as X-ray focusing polychromators in symmetric Laue geometry.
abstract: The focusing properties of cylindrically bent crystals in symmetric Laue geometry are discussed using the formalism of Fresnel diffraction and the analytical solution of the Takagi-Taupin equations for a point source on the entrance surface. The existence of a focal shift in the dynamical focusing effect is pointed out and discussed. The present theoretical framework is applied to experiments performed at the energy-dispersive X-ray absorption spectroscopy beamline of the European Synchrotron Radiation Facility concerning the position and the size of the focal spot obtained from a polychromatic source at a large distance from the bent crystal.
authors.affiliation: European Synchrotron Radiation Facility, Grenoble, France. guigay@esrf.fr
authors.forename: J P
authors.initials: JP
authors.lastname: Guigay
authors.forename: C
authors.initials: C
authors.lastname: Ferrero
authors.forename: D
authors.initials: D
authors.lastname: Bhattacharyya
authors.forename: O
authors.initials: O
authors.lastname: Mathon
authors.forename: S
authors.initials: S
authors.lastname: Pascarelli