In early October, ATLAS teams at the SLAC National Assembly Facility in California, USA, successfully loaded detector modules onto the first ring of the Inner Tracker (ITk) Pixel Inner System. This marks an important step in the assembly of ITk, a next-generation tracker that will transform the way the ATLAS experiment detects particle collisions for the High-Luminosity LHC.

The ring will be located closer to the LHC beampipe than any other part of the ATLAS experiment, lying right at the heart of the detector. It consists of silicon pixel detector modules mounted on lightweight carbon-fibre supports, together with the power, data and cooling services required for operation.

The modules on the first side of the ring are now in place, with the second side scheduled for loading this week. Initial metrology measurements confirm that the modules are correctly positioned, providing an encouraging start to this stage of assembly.

Learn more

• About High-Luminosity ATLAS
• ATLAS enters the high-luminosity era, ATLAS Press Statement, June 2026
• Read more HiLumi ATLAS upgrade stories