Crystal Collimation of 20 MJ Heavy-Ion Beams at the HL-LHC

The concept of crystal collimation at the Large Hadron Collider (LHC) relies on the use of bent crystals that can deflect halo particles by a much larger angle than the standard multi-stage collimation system. Following an extensive campaign of studies and performance validations, a number of crystal collimation tests with Pb ion beams were performed in 2018 at energies up to 6.37 Z TeV. This paper describes the procedure and outcomes of these tests, the most important of which being the demonstration of the capability of crystal collimation to improve the cleaning efficiency of the machine. These results led to the inclusion of crystal collimation into the LHC baseline for operation with ion beams in Run 3 as well as for the HL-LHC era. A first set of operational settings was defined.