CERN shuts down Large Hadron Collider for $1.5B upgrade

CERN shut down the Large Hadron Collider on Monday, ending 18 years of operations that included the landmark 2012 discovery of the Higgs boson.phys+1
The $1.5 billion upgrade will transform the machine into the High-Luminosity LHC, increasing the rate of particle collisions by up to tenfold.interestingengineering+1
The revamped collider is scheduled to begin operations in 2030, expanding the search for dark matter and phenomena beyond the Standard Model.phys+1

The world's most powerful particle accelerator fell silent on Monday as CERN switched off the Large Hadron Collider, marking the beginning of Long Shutdown 3 — a four-year overhaul that will transform the machine into the High-Luminosity LHC.phys+2

End of an Era

The shutdown, planned years in advance, brings to a close 18 years of operations for the LHC in its current form. During that span, the collider delivered landmark results, most notably the 2012 discovery of the Higgs boson by the ATLAS and CMS collaborations. The machine's final physics season began in March 2026, with proton collisions at 13.6 TeV running through the end of June.facebook+4

The upgrade is expected to cost 1.2 billion Swiss francs, roughly $1.5 billion. Thousands of experts will work across CERN's sites and tunnels, replacing all components within a 1.2-kilometer section of the 27-kilometer ring. The work includes installing new 11-12 tesla superconducting magnets and superconducting "crab" cavities designed to increase collision rates at the ATLAS and CMS detectors.interestingengineering+2

What Comes Next

The revamped machine, known as the HiLumi LHC or HL-LHC, is scheduled to begin operations in 2030 and run for approximately a decade. It will increase luminosity — the rate of particle collisions — by up to a factor of ten, dramatically expanding the volume of data available to physicists.theregister+3

That additional data will enable more precise measurements of the Higgs boson's properties and broaden the search for phenomena beyond the Standard Model, including dark matter. The upgrade is also expected to extend the discovery range for new particles by 20 to 30 percent compared to the current LHC.physicsworld+2

A Planned Transition

CERN emphasized that the shutdown is not the end of the accelerator but a transformation. "It's a big upgrade and a good investment," physicist Lucio Rossi, the HL-LHC project leader, said when construction began in 2018. "It will double the lifetime of the LHC up to 2040."physicsworld

Parts of the broader accelerator complex and experimental facilities will begin resuming operation from mid-2028 onward, while the full HL-LHC is prepared for its 2030 start. Data analysis from the LHC's final run will continue throughout the shutdown period.home+1

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