The world’s most powerful particle accelerator, the Large Hadron Collider (LHC), will suspend operations starting Monday for a planned four-year upgrade aimed at significantly enhancing its ability to probe fundamental questions about the universe, including the nature of dark matter.

Located at the CERN laboratory near Geneva, the LHC is a 27-kilometer circular tunnel straddling the French-Swiss border where protons are accelerated to near light speeds and collided using superconducting magnets and advanced accelerating structures. The facility is renowned for its 2012 discovery of the Higgs boson, a particle critical to understanding the origin of mass.

Beginning this week, the collider will cease all experiments as engineers replace key components along 1.2 kilometers of the tunnel. The upgrade, which will transform the LHC into the High Luminosity LHC (HL-LHC), involves installing new superconducting magnets that can focus particle beams more precisely. This will boost the collider’s "luminosity," or collision frequency, by a factor of 10 compared to current levels.

Once complete, the HL-LHC is expected to restart operations in June 2030 and run for about a decade. The enhanced collider will enable between 140 and 200 collisions each time particle bunches intersect within the detectors, compared to around 60 collisions today. Over its run, the HL-LHC could generate up to 100 times more data than its predecessor.

“This is a very important moment. From Monday, we will be entering a new phase,” HL-LHC project chief Markus Zerlauth said. He emphasized the upgrade’s potential to tackle unresolved physics questions and to open the door to many new discoveries.

The extensive renovation is slated to cost approximately 1.2 billion Swiss francs (around $1.5 billion). Funding will be provided primarily through CERN membership fees, supplemented by in-kind contributions from member states, including the United States, Japan, Canada, and China, which are expected to cover 10-15 percent of the total budget.

The increase in collision rates poses a challenge for data storage and analysis, as the collider will produce billions of events per second. To manage this, real-time event selection will be conducted using artificial intelligence systems designed to identify and retain the most scientifically valuable collisions while discarding less relevant data.

The HL-LHC upgrade represents a major step forward in particle physics research, providing a more powerful tool to investigate the universe’s fundamental structure and potentially shed light on elusive phenomena such as dark matter.