ATLAS beam vacuum assembly enters retirement

After more than a decade of service, one of the LHC’s key components for guiding particle beams through the ATLAS experiment has been removed, making way for the High-Luminosity LHC era.

Installed during Long Shutdown 1, this 5.8-metre-long aluminium assembly connected the ATLAS big muon wheel to the endcap toroid, providing the vacuum environment the particle beams needed to travel between them. It replaced an earlier stainless-steel design, helping to reduce radiation exposure and minimise unwanted background signals in the ATLAS experiment.

Extracting the 300 kg assembly was a delicate operation. Suspended from the surface hall crane over 80 metres above it, the assembly had to be carefully manoeuvred through the experiment with only a few centimetres of clearance from surrounding components, all while teams worked in a radiologically challenging environment.

As this second-generation assembly retires, a new design developed for the High-Luminosity LHC will take its place. Its removal marks the end of a successful chapter for both ATLAS and the LHC, celebrating more than a decade of the assembly’s reliable operation and the efforts of the many people who brought it from design to reality.