CERN’s Large Hadron Collider was first turned on in 2008 , with the first beam of protons circulating on 10 September 2008. CERN’s current shutdown for upgrades began on 29 June 2026 , and the High-Luminosity LHC is expected to start up in 2030.

Quick context

  • The LHC is CERN’s main particle accelerator near Geneva.
  • Its 2026 shutdown is for the third long maintenance and upgrade period, not because of any safety issue.
  • The next major phase, the High-Luminosity LHC, is planned to come online in 2030.

Timeline

  • 1954 : CERN was officially founded.
  • 2008 : the LHC was first switched on.
  • 2026 : the LHC was switched off for upgrades.
  • 2030 : the upgraded High-Luminosity LHC is scheduled to begin operation.

If you meant CERN itself rather than the LHC, CERN began in 1954.