The Large Hadron Collider (LHC), the world-famous particle accelerator which was used to discover the Higgs boson particle in 2012, has restarted after a three-year break to perform maintenance and upgrades. The accelerator can now resume its work to uncover more about the constituent particles of the universe.
The LHC is housed in a 17-mile circumference tunnel beneath the border of France and Switzerland and was built by the European Organization for Nuclear Research (CERN). On Friday, 22 April, it shot two beams of protons at each other with an energy of 450 billion electronvolts (450 GeV).
“These beams circulated at injection energy and contained a relatively small number of protons,” said Rhodri Jones, the head of CERN’s Beams Department, in a statement. “High-intensity, high-energy collisions are a couple of months away. But first beams represent the successful restart of the accelerator after all the hard work of the long shutdown.”
The three year maintenance period, called Long Shutdown or LS2, began in December 2018 and included improvements to the accelerators which should allow even higher energy beams to be produced, of up to 6.8 TeV per beam. The magnets that direct and focus the particle beams have been fitted with an improved electrical insulation system as well, and some of the magnets have been replaced.
Overall, the improvements to the LHC will allow the particle accelerator to work at higher energies, and also to perform more frequent collisions. The researchers working with the accelerator hope this will enable them to learn more about the Higgs boson particle and to further test the Standard Model of physics which describes three of the four fundamental forces: Electromagnetic, weak nuclear, and strong nuclear forces.
“The machines and facilities underwent major upgrades during the second long shutdown of CERN’s accelerator complex,” said Mike Lamont, CERN’s Director for Accelerators and Technology. “The LHC itself has undergone an extensive consolidation program and will now operate at an even higher energy and, thanks to major improvements in the injector complex, it will deliver significantly more data to the upgraded LHC experiments.”