Superconducting superstructure for the TESLA collider: A concept

We discuss a new layout of a cavity chain (called superstructure) allowing, we hope, a significant cost reduction due to a simplification of the rf system of the TESLA linear collider. The proposed scheme increases the fill factor and thus makes an effective gradient of the accelerator higher. In this paper computations and preliminary measurements on existing copper models of the TESLA Test Facility accelerating structures are presented. A new copper model of the scheme has been ordered, made of four 7-cell standing wave cavities, which according to the results of computations and measurements seems to be the most promising version. Experiments with a beam will be necessary to prove that the proposed layout can be used for the acceleration.