A New Damped and Tapered Accelerating Structure for CLIC, these proceedings

The main performance limits when designing acceler-ating structures for the Compact Linear Collider (CLIC) for an average accelerating gradient above 100 MV/m are electrical breakdown and material fatigue caused by pulsed surface heating. In addition, for stable beam operation, the structures should have low short-range transverse wake-fields and much-reduced transverse and longitudinal long-range wakefields. Two damped and tapered accelerating structures have been designed. The first has an accelerat-ing gradient of 112 MV/m with the surface electrical field limited to 300 MV/m and the maximum temperature in-crease limited to 100 oC. The second, with an accelerat-ing gradient of 150 MV/m, has a peak surface electrical field of 392 MV/m and a maximum temperature increase of 167 oC. Innovations to the cell and damping waveguide geometry and to the tapering of the structures are presented, and possible further improvements are proposed.