CERN starts replacing LHC magnets for high-luminosity upgrade
CERN has begun dismantling sections of the Large Hadron Collider to install stronger superconducting magnets for the High-Luminosity upgrade. The new inner triplet magnets will produce fields about 40% stronger, allowing tighter beam focusing and more collisions. The first new quadrupole is expected in the tunnel in early 2029.
The LHC's 27-kilometer ring uses a variety of magnet types, each with a specific role in steering beams. The inner triplets, composed of three quadrupoles, are crucial for focusing beams just before collisions at the ATLAS and CMS detectors. The upgrade replaces these with niobium-tin coils, achieving 11.3 tesla fields—a 40% increase over the current niobium-titanium magnets.
This work occurs during the third long shutdown (LS3). The operation involves removing 28 superconducting magnets and installing 16 cryostats and 28 cryo-assemblies. The first new quadrupole is slated for tunnel arrival in early 2029. While ATLAS and CMS get the new triplets, ALICE and LHCb will retain their existing magnets but still receive upgrades to benefit from the overall luminosity increase.
The High-Luminosity upgrade could dramatically expand the dataset for particle physics, potentially revealing rare processes or new particles that reshape fundamental theories. This may lead to breakthroughs in understanding dark matter or the Higgs boson, but such gains are indirect and long-term. Society could benefit from technological spin-offs in superconducting materials and cryogenics, as well as renewed public interest in science. However, the project's high cost and extended timeline mean tangible societal returns remain uncertain, affecting taxpayers and research funding priorities.