CERN has started pulling out 28 magnets installed when the collider was built

CERN has begun taking apart the sections of the Large Hadron Collider on either side of the ATLAS and CMS experiments, with the goal of removing 28 superconducting magnets that went into the machine between 2005 and 2007. Teams started dismantling on 7 September, and the first magnet interconnection was cut in the week CERN announced the milestone on 17 September.

The magnets are the focusing quadrupoles known as inner triplets, and their replacements are built from a different superconductor and are about 40% stronger. The swap is the physical core of the High-Luminosity LHC upgrade.

Inner triplets and the 28 magnets

In CERN’s own report on the disconnection, an inner triplet is defined as a set of three quadrupoles sitting on either side of one of the four big experiments. Their job is to squeeze the proton beams to a tiny cross-section just before the particles meet, which raises luminosity, the rate of collisions that produces data. The 28 magnets being removed include the inner triplets on both sides of ATLAS and CMS, and CERN’s article says teams are pulling the surrounding machine sections apart in order to reach them.

ALICE and LHCb keep their present triplets. According to CERN, those two experiments do not need the same jump in instantaneous luminosity, so their triplets will be improved rather than replaced, letting both benefit from the higher collision rate.

Twenty years of service and a generational handover

Markus Zerlauth, the HiLumi LHC project leader, framed the moment as a passing of the torch. The current inner triplets date back to the construction of the LHC and were installed between 2005 and 2007, he said, and after nearly twenty years of operation they will give way to a more powerful generation of magnets. He called it truly remarkable to witness such a handover from one generation of innovation to the next, and described the day as a major milestone for CERN and especially for his project team.

CERN’s Director-General, Mark Thomson, visited the tunnel to mark the start of the disconnection, according to the same report. The accelerator side of the operation is run by the Long Shutdown 3 coordination team under Jean-Philippe Tock, who said that replacing the old magnets with the new HiLumi LHC inner triplets is crucial for the coming high-luminosity years.

Niobium-tin coils and the 2029 schedule

The new triplets use niobium-tin superconducting coils in place of the niobium-titanium used in the original magnets, and they reach a field of 11.3 tesla, about 40% stronger, a point ScienceDaily’s republication of the CERN text restates. Niobium-tin tolerates higher fields, which lets the quadrupoles focus the beams harder inside the same tunnel. CERN says 16 cryostats and 28 cryo-assemblies will be installed in total, which it calls a major undertaking.

Nothing new goes in for a while, and the gap is deliberate. Tock said the first quadrupole of the new triplets should arrive in the tunnel at the start of 2029, so the removal work now under way is followed by years of preparation, cleaning and testing in the emptied sections before the replacement hardware shows up. The long lead time reflects the scale CERN itself describes: 16 cryostats and 28 cryo-assemblies. The upgrade as a whole, Tech Times reports, covers about 1.2 kilometers of accelerator infrastructure and is priced at roughly $1.5 billion, with Thomson, who became Director-General on 1 January 2026, describing it as a chance to explore the universe in ways not possible before.

The upgrade these magnets belong to

The disconnection follows the end of the collider’s third run. Tech Times reported that Run 3 ended on 27 June 2026, that the shutdown is planned to last four years, and that the machine is due back in June 2030. CERN’s High-Luminosity LHC page sets the aim as a tenfold increase in integrated luminosity beyond the original design, and at least 15 million Higgs bosons per year compared with around three million from the LHC in 2017.

The project’s own description calls it a decade-long endeavor, approved by the CERN Council in the 2015 Medium Term Plan and built with niobium-titanium and niobium-tin magnets, with critical components developed largely by the LARP program run from the United States. It also warns that more collisions place unprecedented demands on vacuum, cryogenics and machine protection, which is part of why the old hardware has to come out cleanly before anything new is installed. Oliver Brüning, CERN’s Director for Accelerators and Technology, is quoted in that coverage saying the LHC has exceeded every expectation. The 28 magnets now being cut free are the ones that sat at the heart of that run, and the first of their successors is not due in the tunnel until early 2029.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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