X-ray Interferometry with the heterodyne nearfield speckles technique for beam size monitoring at FCC-ee

Abstract

By recording the interference pattern between X-ray synchrotron radiation emitted by an electron beam and the tiny portion of radiation scattered by a stochastic distribution of nanoparticles, one can measure the first-order transverse coherence of the radiation. Under the conditions of applicability of the Van Cittert and Zernike theorem, the spatial coherence is linked to the transverse intensity distribution of the source, which can be used for beam diagnostics at the projected Future Circular Collider at CERN.In this work, the method is evaluated theoretically and is furthermore tested by simulating the production of the synchrotron radiation and its propagation through the involved optical elements. The method is then shown to be capable for determining the transverse beam size of the Future Circular Collider on a bunch-per-bunch basis and to be feasible with today's technology.