Fabrication and Design of the Main Linacs for CLIC with Damped and Detuned Wakefield Suppression and Optimised Surface Electromagnetic Fields

We report on the suppression of long-range wakefields in the main linacs of the CLIC collider. This structure operates with a 120 degree phase advance per cell. The wakefield is damped using a combination of detuning the frequencies of beam-excited higher order modes and by light damping, through slot-coupled manifolds. This serves as an alternative to the present baseline CLIC design which relies on heavy damping. Detailed simulations of both the optimised surface fields resulting from the monopole mode, and from wakefield damping of the dipole modes, are discussed. We report on fabrication details of a structure consisting of 24 cells, diffusion bonded together. This design, known as CLICDDSA, takes into practical mechanical engineering issues and is the result of several optimisations since the earlier CLICDDS designs. This structure is due to be tested for its capacity to sustain high gradients at CERN.