Proton Synchrotron Booster

The Proton Synchrotron Booster at CERN is an accelerator made up of four superimposed synchrotron rings that receive beams of protons from the linear accelerator Linac 2 or 4 at 50 MeV and accelerate them to 1.4 GeV for injection into the PS.

For more information, see Wikipedia.