Modeling and metrological analysis of an X-ray diffractometer for crystal-assisted collimation in particle accelerator

A FEM model of a double-crystal diffractometer and its metrological analysis is proposed for a complete characterization of bent crystals involved in the process of particles collimation in the Large Hadron Collider at CERN, in terms of miscut, bending and torsion angles. The model reproduces the laboratory measurement procedure based mainly on a 2D scanning algorithm and a π rad flip of the crystal under test. In this paper, we briefly present a physical analysis of the diffractometer, uncertainty sources definition, and their effect on the final results. The final goal is to reach a measurement uncertainty of 1 μrad with a coverage factor k = 3.