Adaptive collimator design for future particle accelerators

The function of collimators in the Large Hadron Collider (LHC) is to control and safely dispose of the halo particles that are produced by unavoidable beam losses from the circulating beam. Even tiny proportions of the 7TeV beam have the stored energy to quench the superconducting magnets or damage parts of the accelerator if left unchecked. Particle absorbing Low-Z material makes up the active area of the collimator (jaws). Various beam impact scenarios can induce significant temperature gradients that cause deformation of the jaws. This can lead to a reduction in beam cleaning efficiency, which can have a detrimental effect on beam dynamics. This has led to research into a new Adaptive Collimation System (ACS). The ACS is a re-design of a current collimator already in use at CERN, for use in the HL-LHC. The ACS will incorporate a novel fibre-optic-based measurement system and piezoceramic actuators mounted within the body of the collimator to maintain jaw straightness below the 100µm specification. These two systems working in tandem can monitor, and correct for, the jaw structural deformation for all impact events. This paper details the concept and technical solutions of the ACS as well as preliminary validation calculations.