Studies on Nonlinear Post-linac Protection for CLIC

The post-linac energy collimation system of CLIC is designed to fulfill an essential function of protection of the Beam Delivery System (BDS) against miss-steered beams generated by failure modes in the main linac. Guaranteeing the collimator survivability in case of direct beam impact is very challenging, if we take into account the need to deal with an unprecedented transverse beam energy density per beam of the order of GJ/mm². This translates into a high damage potential of uncontrolled beams. In this paper we present an alternative nonlinear energy collimation system as a potential solution to guarantee the survival of the collimators. The performance and error tolerances of this system are studied by means of beam tracking simulations, and compared with those of the conventional baseline CLIC energy collimation system.