Proton Synchrotron

The Proton Synchrotron (PS, sometimes also referred to as CPS) is a particle accelerator at CERN. It is CERN's first synchrotron, beginning its operation in 1959. For a brief period the PS was the world's highest energy particle accelerator. It has since served as a pre-accelerator for the Intersecting Storage Rings (ISR) and the Super Proton Synchrotron (SPS), and is currently part of the Large Hadron Collider (LHC) accelerator complex. In addition to protons, PS has accelerated alpha particles, oxygen and sulfur nuclei, electrons, positrons, and antiprotons. Today, the PS is part of CERN's accelerator complex. It accelerates protons for the LHC as well as a number of other experimental facilities at CERN. Using a negative hydrogen ion source, the ions are first accelerated to the energy of 160 MeV in the linear accelerator Linac 4. The hydrogen ion is then stripped of both electrons, leaving only the nucleus containing one proton, which is injected into the Proton Synchrotron Booster (PSB), which accelerates the protons to 2 GeV, followed by the PS, which pushes the beam to 25 GeV. The protons are then sent to the Super Proton Synchrotron, and accelerated to 450 GeV before they are injected into the LHC. The PS also accelerate heavy ions from the Low Energy Ion Ring (LEIR) at an energy of 72 MeV, for collisions in the LHC. The synchrotron (as in Proton Synchrotron) is a type of cyclic particle accelerator, descended from the cyclotron, in which the accelerating particle beam travels around a fixed path. The magnetic field which bends the particle beam into its fixed path increases with time, and is synchronized to the increasing energy of the particles. As the particles travels around the fixed circular path they will oscillate around their equilibrium orbit, a phenomenon called betatron oscillations. In a conventional synchrotron the focusing of the circulating particles is achieved by weak focusing: the magnetic field that guides the particles around the fixed radius decreases slightly with radius, causing the orbits of the particles with slightly different positions to approximate each other.