The performance of the SPS as LEP injector

The injection of positrons into the first octant of the LEP (Large Electron Positron Collider) during the LEP injection tests in 1988, required the SPS (Super Proton Synchrotron) to operate as an injector for the LEP. Positrons were accelerated in the SPS from an energy of 3.5 GeV to about 18 GeV and extracted into LEP during the one-week test. This test, as well as the further commissioning of the SPS with leptons, could be made without perturbation to the physics program. The leptons were accelerated in three cycles, interleaved between the proton cycles, and four bunches of positrons or electrons were accelerated on each of them. Bunches with intensities exceeding the design value of 0.8×10¹⁰ were accelerated. Following preliminary studies, countermeasures against various collective effects allowed the acceleration of up to 2.6×10¹⁰ particles per bunch. The required momentum for LEP injection of 20 GeV could also be achieved