Design of an Accelerating Structure for a 500 GeV CLIC using ACE3P

An optimized design of the main linac accelerating structure for a 500 GeV first stage of CLIC is presented. A similar long-range wakefield suppression scheme as for 3 TeV CLIC based on heavy waveguide damping is adopted. The accelerating gradient for the lower energy machine is 80 MV/m. The 500 GeV design has larger aperture radius in order to increase the maximum bunch charge and length which is limited by the short-range wakefields. The cell geometries have been optimized using a new parametric optimizer for Ace3P and details of the RF cell design are described. Field parameters for the full structure are calculated using a power flow equation.