First two years operational experience with LEP

The authors summarize the experience over the first two years of LEP (Large Electron-Positron colliding beam accelerator) operation giving typical and peak performance figures. During 1989 a beam of positrons was injected into LEP from the SPS (Super Proton Synchrotron) and the first full turn was completed. Experiments detected their first Z/sup 0/ particles. The machine was operated in a mixed mode of machine studies and operation for physics. At the end of this period a total of over 1.7 inverse picobarns of integrated luminosity had been recorded per experiment, resulting in a total of more than 70000 Z/sup 0/s detected. The energy of each fill was varied, and half the number of fills were at the Z/sup 0/s peak. During 1990, LEP was operated in the same way as in 1989; 12.1 inverse picobarns and three quarters of a million Z/sup 0/s were produced. Physics fills of 6-h duration in 1989 were increased to 10-12 h in 1990 as the lifetimes of the beams increased with the steadily improved vacuum in the ring.< >