CERN cools giant 20-ton magnets at -456°F for 10x particle collision

CERN is nearing completion of a critical test facility for the High-Luminosity Large Hadron Collider (HL-LHC), an upgrade designed to increase the accelerator’s luminosity—the number of particle collisions—by a factor of ten. The facility includes a 95-meter-long test stand replicating new magnet segments weighing between 10 and 20 tons, which must operate at an ultra-cold temperature of -456°F (-271°C) using superfluid helium to achieve superconductivity. These advanced magnets, made from a novel niobium-tin alloy, can generate magnetic fields of 11.3 tesla, significantly stronger than the current 8.3-tesla magnets, enabling denser particle beams and more precise collision experiments. The test stand, known as the “IT String,” serves as a full-scale rehearsal to validate the integration and performance of these components under extreme conditions before installation in the main LHC tunnel. This phase involves managing complex electrical circuits carrying over 100,