Super Proton Synchrotron

Super Proton Synchrotron. The Super Proton Synchrotron is a major particle accelerator located at the CERN laboratory near Geneva. It began operation in 1976 and was the first machine to provide proton-proton collisions at energies high enough to produce the W and Z bosons. As a critical component of CERN's accelerator complex, it has served both as a collider in its own right and as the injector for larger machines like the Large Electron–Positron Collider and the Large Hadron Collider.

History and development

The project was approved by the CERN Council in the early 1970s, with construction led by Director-General John B. Adams. Its design was heavily influenced by the success of the Proton Synchrotron and aimed to push proton energies into a new regime. The machine was built in a circular tunnel spanning the France–Switzerland border, with civil engineering works beginning in 1972. Key figures in its development included Simon van der Meer, whose work on stochastic cooling was vital for accumulating dense particle beams. The accelerator achieved its first beam in 1976, marking a significant leap for European particle physics and establishing CERN as a world leader in high-energy research.

Technical specifications

The machine is a circular synchrotron with a circumference of 6.9 kilometres, situated approximately 40 metres underground. It was originally designed to accelerate protons to an energy of 400 GeV, later upgraded to 450 GeV. The ring employs 1,317 bending dipole magnets and 460 focusing quadrupole magnets to steer and contain the particle beams. It can also accelerate other particles, including antiprotons, electrons, positrons, and heavy ions like lead. For its role as an injector, it receives protons from the Proton Synchrotron and further boosts their energy before sending them to the Large Hadron Collider. The vacuum system maintains an ultra-high pressure to minimize beam interactions with residual gas molecules.

Scientific discoveries and experiments

The most celebrated discovery made directly using this accelerator was the experimental confirmation of the W and Z bosons by the UA1 and UA2 collaborations in 1983, a feat for which Carlo Rubbia and Simon van der Meer received the Nobel Prize in Physics in 1984. It also hosted the NA31 experiment which made precise measurements of CP violation in the kaon system. Later, as a fixed-target machine, experiments like COMPASS studied the spin structure of the nucleon and the spectrum of hadrons. The NA62 experiment continues to investigate rare decays of kaons, searching for signs of physics beyond the Standard Model.

Upgrades and future prospects

The machine has undergone several major upgrade programs to meet the demands of new physics experiments and its role as an injector. A significant enhancement was the installation of the SPS as a heavy-ion injector for the LHC's ALICE experiment. The ongoing High-Luminosity Large Hadron Collider project requires further upgrades to its injection systems to provide higher-intensity beams. Future plans within CERN's long-term strategy, as outlined in the European Strategy for Particle Physics, consider the accelerator as a potential key component for new facilities, such as a high-intensity proton source for a Fixed-Target Facility or as part of a complex feeding a future Future Circular Collider.

See also

* Large Hadron Collider * Proton Synchrotron * CERN * Particle accelerator * W and Z bosons

Category:Particle accelerators Category:CERN