Long-term test of a LEP prototype superconducting cavity in the CERN SPS

Using a superconducting LEP (Large Electron Positron Collider) prototype cavity, an e/sup +/ beam was accelerated at E/sub a/=5.5 MV/m. The SPS (Super Proton Synchrotron) proton accelerator/proton-antiproton collider/LEP injector was chosen for the implementation of the cavity. After 8000 h at 4.5 K E/sub a//sup max/ remained unchanged (7.1 MV/m); the Q-value (5 MV/m) was 2/3*10/sup 9/. No major system failure occurred. RF feedback guaranteed very low fluctuations of the cavity field amplitude and phase.<>