Application of superconducting RF to linear colliders

A workshop on a TeV energy superconducting linear accelerator (TESLA) is described. Parameter sets for five machines were generated, from 0.1 TeV to 1.5 TeV CM, including Z/sup 0/ and Top factories. Linear colliders have the advantage that the length can be extended periodically while using progressively higher gradients from 15 MeV/m to 40 MeV/m. The major challenges are to increase the gradients from the 5-10 MeV/m possible today and to lower the costs. Recently, at 1.5 and 3 GHz, several labs have provided existence proofs for Eacc>15 MeV/m in multicell structures. With specially developed heat-treatment techniques to reduce field emission, 1-cell Nb cavities regularly reach fields corresponding to Eacc=25 MeV/m. Many ideas were advanced at the workshop for lowering structure costs.<>