Superconducting Accelerating Cavities for High Energy e+-e--Storage Rings

In electron storage rings the high demand of RF power contributes considerably to both construction and operating costs. A cost optimization shows, that a storage ring with superconducting cavities is smaller and cheaper than one with normal cavities. Exchanging normal into superconducting cavities in an existing storage ring can increase the end energy by about 40%. Open questions like performance, especially in presence of synchrotron radiation, effects of higher order modes and handling of high beam power need tests in an operating storage ring. The preparations and components of a test in DORIS are described.