The CERN SPS Proton-Antiproton Collider

The SPS now operates for about 40% of the time as a proton-antiproton collider at a centre of mass energy of 630 GeV. Towards the end of 1984 the SPS achieved a peak luminosity of 3.6×1029cm-2s-1, with a luminosity lifetime of 28 hours and an average integrated luminosity of 5nb-1 per day. This report reviews the operational experience and limitations of the collider and describes the improvements which will be implemented to increase its luminosity by an order of magnitude.