Collimation of Plasma-produced X-rays by Spherical Crystals: Ray-tracing Simulations and Experimental Results. M. Sanchez del Rio a), M. Fraenkel b), A. Zigler b), A. Ya. Faenov c) and T. A. Pikuz c) a) European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex 9, France b) Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel c) Multicharged Ions Spectra Data Center of VNIIFTRI, Russian Committee of Standards, Moscow Region, 141570, Russia ABSTRACT Ray-tracing simulations -validated by experimental results- demonstrate that high intensity collimated X-ray beams can be produced from an isotropic X-ray source. A spherically bent Mica crystal was used to collimate and monochromatize X- rays emitted by a femtosecond laser-produced plasma. The result is a short pulse X-ray beam with a high degree of collimation (less than 1 mrad divergence), good spectral resolution (10-2