The Super Proton Synchrotron

The Super Proton Synchrotron (SPS) is the second-largest machine in CERN’s accelerator complex. Measuring nearly 7 kilometres in circumference, it takes particles from the Proton Synchrotron and accelerates them to provide beams for the Large Hadron Collider, the NA61/SHINE and NA62 experiments, the COMPASS experiment and the CNGS project.

The SPS became the workhorse of CERN’s particle physics programme when it switched on in 1976. Research using SPS beams has probed the inner structure of protons, investigated nature’s preference for matter over antimatter, looked for matter as it might have been in the first instants of the universe and searched for exotic forms of matter. A major highlight came in 1983 with the Nobel-prize-winning discovery of W and Z particles, with the SPS running as a proton-antiproton collider.

The SPS operates at up to 450 GeV. It has 1317 conventional (room-temperature) electromagnets, including 744 dipoles to bend the beams round the ring. The accelerator has handled many different kinds of particles: sulphur and oxygen nuclei, electrons, positrons, protons and antiprotons.