The Large Hadron Collider (LHC) has been churning out groundbreaking science ever since it went into operation in 2010. The giant particle accelerator, perched on the border of France and Switzerland, has gotten several upgrades over the years, and a new project is just getting underway now. CERN has broken ground on the High-Luminosity LHC (HL-LHC), which will result in more particle collisions and more data to help scientists unravel the mysteries of the universe.
The LHC operates by accelerating protons around the 16.8-mile (27-kilometer) ring using cryogenically cooled, superconducting magnets. Some of those protons smack into each other in the detectors at nearly the speed of light. The exotic matter that spills out is short-lived, but the decay products can tell us about the fundamental laws of the universe. With more collisions, you can gather more data on those particles. That’s what the HL-LHC is about.
CERN has planned for this upgrade since shortly after the LHC came online. Currently, the LHC can manage a billion billion proton collisions per second (a one followed by eighteen zeros). The project is called “High-Luminosity” because it’s aimed at increasing the number of particle collisions by as much as seven times. That could mean a 10-fold increase in data collected from collisions. The HL-LHC could determine the properties of known particles like the Higgs boson more accurately, and discover new particles that fill in the gaps in our understanding of the universe.
To make that happen, the LHC is going to need new buildings for cooling and ventilation, shafts in the ground, and underground caverns that house magnets and cryogenic equipment. In all, 1.2 kilometers (almost 4,000 feet) of the ring will be replaced.
The HL-LHC will squeeze the beam of circulating protons even tighter than it is now by passing it them through a new bank of 120 magnets, including 24 superconducting quadrupoles and four superconducting dipoles (see above). The new magnets should have a field strength of 11.5 tesla. The current magnets top out at 8.3 tesla. As part of the upgrade, CERN also intends to make the new components more accessible to speed up future maintenance.
The HL-LHC is a significant upgrade to the instrument, so it won’t be complete until 2026 at the earliest. However, the LHC will continue operating at its current capacity for most of that time. CERN expects two brief shutdowns for maintenance and upgrades before bringing the HL-LHC online. Future shutdowns should be shorter after the revamped instrument is online.