A Laue-Bragg monolithic beam splitter for efficient X-ray 2-beam imaging

Newly emerging techniques for probing matter simultaneously by two spatially and angularly separated X-ray beams require efficient and versatile beam splitting. We present a Laue-Bragg monolithic crystal beam splitter in the form of an L-shaped monolithic Si crystal. By simultaneous Laue and Bragg diffractions the X-ray beam is split into a transmitted polychromatic and a diffracted monochromatic branch with a spatial separation of tens of millimeters. The energy spectrum of the transmitted branch can be tuned via diffraction on a second crystal re-creating a beam intersection on the sample. We propose three multi-modal imaging setups exploiting the large angular separation of the two intersecting beams provided by the proposed optics. Photon efficiency and dual-energy operation are the main assets of our scheme as compared to other existing setups. The theoretical description for an energy range between 10 keV and 30 keV was developed. (C) 2012 Elsevier B.V. All rights reserved.