Protons back with a splash
After a three-year hiatus, protons are once again circulating in the LHC, as physicists make final preparations for the start of Run 3. At the beginning of October, a beam of 450 GeV protons made its way from the Super Proton Synchrotron (SPS) down the TI2 beamline towards Point 2, where it struck a dump block and sprayed secondary particles into the ALICE experiment (see image). Beam was also successfully sent down the TI8 transfer line, which meets the LHC near to where the LHCb experiment is located.
Today, counter-rotating protons were finally injected into the LHC, marking the latest milestone in the reawakening of CERN’s accelerator complex, which closed down at the end of 2018 for Long Shutdown 2 (LS2). Two weeks of beam tests are planned, along with first low-energy collisions in the experiments, before the machine is shut down for a 3-4 month maintenance period. Meanwhile, the experiments are continuing to ready themselves for more luminous Run-3 operations.