Tests on S-Band Superconducting Niobium Prototype Accelerator Structures

The fabrication, processing, and measurement of two S-band niobium prototype electron accelerator structures are discussed. Maximum surface magnetic fields were typically between 250 and 550 Oe, corresponding to average energy gradients between 4.6 and 6.5 MeV/m, with Q0 values typically greater than 5 × 109. The structures which were electropolished gave more reproducible results than those which were chemically polished.