1976: the SPS is commissioned

Measuring 7 km in circumference, the Super Proton Synchrotron (SPS) was the first of CERN’s giant rings. Built in a tunnel, it was also the first accelerator to cross the Franco–Swiss border.

Initially conceived as a proton accelerator with a beam energy of 300 GeV, the SPS operates today at up to 450 GeV, and has handled many different kinds of particles.

When it switched on, the SPS became the workhorse of CERN’s particle physics programme, providing beams to two large experimental areas. 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’s life and searched for exotic forms of matter.

A major highlight of the SPS’s career came in 1983 with the announcement of the Nobel-prize-winning discovery of W and Z particles. This discovery was made with the SPS running as a collider, smashing protons and antiprotons together head-on. Today, the SPS continues to support an experimental programme, and it has a new role, as the last link in the accelerator chain providing beams for the Large Hadron Collider.