Recent LHC SR Interferometer Simulations and Experimental Results

At the CERN Large Hadron Collider (LHC), among the different systems exploiting Synchrotron Radiation (SR) for beam diagnostics, interferometry is under study as a non-invasive technique for measuring absolute beam transverse sizes. Extensive numerical simulations, recently completed for characterising the spatial coherence of the LHC SR source, facilitated the optimisation of the LHC interferometer design and the existing prototype system tested in the past has been refurbished to include the new simulation findings. This contribution describes the simulation specificity and then focuses on first measurements performed at the beginning of the LHC run 3. Such experiments allowed to obtain a first validation of the expected system performance at the injection energy of 450 GeV. A complete benchmark of the simulations will be carried out in 2022 as soon as the LHC will reach its top energy of 6.8 TeV.