At 10:25 a.m., Swiss time, the LHC team used remote controls to remove the last collimator that blocked one of the LHC’s two beam pipes. One minute later, accelerator experts sent a beam of protons clockwise into the pipe at an energy of 450 billion electronvolts. Traveling at close to the speed of light, the protons completed their first turn around the ring. The CERN Control Centre documented the historic event in this electronic logbook.
A beam screen near the injection point recorded the beam’s passage right after its injection and after its first round trip (two orange dots in the center left graph). Beam position monitors throughout the ring reported the vertical and horizontal positions of the beam (center right graph).
A few minutes later, after making some adjustments, the LHC team injected another proton beam that traveled around the ring twice. Four and a half hours later, the team succeeded in sending a beam of protons around the LHC’s second beam pipe in the opposite direction.
