Plate Nº 50 · recorded October 13, 2026
PhysicsReported finding
CERN Begins Replacing 28 LHC Magnets in HiLumi Overhaul
On 7 September 2026, CERN cut the first magnet interconnections at ATLAS and CMS, launching a multi-year replacement of 28 superconducting magnets for the High-Luminosity LHC upgrade.
By Marcus Bennett2 min read493 words
In brief
- 7 September 2026: CERN cut the first LHC magnet interconnections for HiLumi replacement
- 28 superconducting magnets will be removed around the ATLAS and CMS detectors
- New niobium-tin inner triplets generate 11.3 tesla, about 40% stronger than current niobium-titanium units
- First new quadrupole scheduled for tunnel delivery at the start of 2029
- Current inner triplets were installed between 2005 and 2007, after roughly twenty years of operation
CERN technicians cut the first magnet interconnections on 7 September, beginning a multi-year teardown of 28 superconducting magnets that frame the ATLAS and CMS detectors inside the 27-km Large Hadron Collider (LHC). Director-General Mark Thomson walked the tunnel on 17 September to mark the start of the work.
What do these magnets actually do?
Inner triplets are sets of three quadrupole magnets — the most precise focusing elements in the LHC. They sit on each side of the four main experiments and squeeze the circulating proton beams down to a tight point at the collision point.
The tighter the squeeze, the higher the chance two protons meet. That rate, called luminosity, sets the ceiling on how much data the experiments can record each second. Higher luminosity means more collisions, and more collisions mean more chances to spot rare processes.
Takeaway: Inner triplets govern how tightly beams meet, and luminosity governs how much physics each run produces.
Why pull them out now?
The replacements belong to CERN's High-Luminosity LHC, or HiLumi LHC, project and form part of Long Shutdown 3 (LS3). The current triplets have operated since installation between 2005 and 2007 — roughly twenty years of beam time behind them.
"The replacement of these magnets with the new HiLumi LHC inner triplets is crucial for the coming high-luminosity years," said Jean-Philippe Tock, head of the LS3 Coordination Team. "The first quadrupole of the new triplets should arrive in the tunnel at the start of 2029. In total, 16 cryostats and 28 cryo-assemblies will be installed — a major undertaking."
The new triplets swap niobium-titanium coils for niobium-tin superconducting coils. Niobium-tin tolerates stronger fields: the new magnets generate 11.3 tesla, about 40% more than the units they replace.
Takeaway: Twenty-year-old magnets come out for niobium-tin versions that push the field 40% higher.
Which experiments get the upgrade?
ATLAS and CMS, the two general-purpose detectors at the heart of the LHC physics programme, will receive the new triplets. ALICE and LHCb, which study heavy-ion collisions and b-physics respectively, will keep their current units — engineers will still improve them so they benefit from the wider luminosity increase.
"Today's event is a major milestone for CERN, especially for the HiLumi LHC project team," said Markus Zerlauth, HiLumi LHC Project Leader. "After nearly twenty years of operation, they will give way to a new generation of even more powerful magnets. It's truly remarkable to witness such a handover from one generation of innovation to the next."
Thomson toured the tunnel alongside Oliver Brüning, Director for Accelerators and Technology, Zerlauth, and Tock. The first new quadrupole reaches the tunnel in early 2029; the rest of the HiLumi hardware follows through the long shutdown, with higher collision rates waiting on the other side of LS3.
Takeaway: ATLAS and CMS get the new triplets; ALICE and LHCb stay on upgraded versions of their originals.
via CERN News (Source)
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News editor covering regulation, policy and their impact on general science news at SciBeat.
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