Performance of superconducting cavities for CEBAF

The Continuous Electron Beam Accelerator Facility (CEBAF) consists of approximately 160 m of 5-cell niobium cavities manufactured from high thermal conductivity niobium with residual resistance ratio (RRR) values >250. After an initial six month period of first article manufacturing at a rate of three cavities per month, the full production rate of twelve cavities per month was reached in October 1990. These cavities are chemically treated at CEBAF, assembled into hermetically sealed cavity pairs, and tested in a vertical configuration prior to installation in the accelerator. The performance of all cavities received from the manufacturer and tested at CEBAF has exceeded CABAF´s design criteria for Q values >2.4*10/sup 9/ at 2 K and accelerating gradients E/sub acc/ >5, MV/m. Q/sub 0/ values as high as 10/sup 10/ and accelerating gradients of E/sub acc/ 18 MV/m have been achieved.<>