A major upgrade of the collimation system of the Large Hadron Collider (LHC) began during the first long shutdown of CERN’s accelerator complex (LS1, 2013–2015) and continued during LS2 (2019–2021), in preparation for the High-Luminosity LHC (HL-LHC). As its name suggests, the HL-LHC will surpass the LHC in terms of luminosity, i.e. the number of collisions that take place within the LHC experiments. The accelerator’s equipment therefore requires enhanced protection, which is where the collimation system comes in. What is a collimator? Collimators are movable blocks made of materials that can absorb particles. Shaped like jaws, they close tightly around the beam to clean up particles that stray from their path. The materials used for these jaws and their various components are capable of withstanding extremes of pressure and temperature, as well as high levels of radiation. Why do beams need cleaning? Particles that stray from the beam path could collide with sensitive accelera