Crab cavities enter next phase
Rama Calaga describes the latest progress in building the superconducting radio-frequency “crab” cavities needed to maximise the scientific output of the High-Luminosity LHC.
The imminent start of LHC Run 3 following a vast programme of works completed during Long Shutdown 2 marks a milestone for the CERN accelerator complex. When stable proton beams return to the LHC this year (see LHC Run 3: the final countdown), they will collide at higher energies (13.6 compared to 13 TeV) and with higher luminosities (containing up to 1.8 × 1011 protons per bunch compared to 1.3–1.4 × 1011) than in Run 2. Physicists working on the LHC experiments can therefore look forward to a rich harvest of results during the next three years. After Run 3, the statistical gain in running the accelerator without a significant luminosity increase beyond its design and ultimate values will become marginal. Therefore, to maintain scientific progress and to exploit its full capacity, the LHC is undergoing upgrades that will allow a decisive increase of its luminosity during Run 4, expected to begin in 2029, and beyond.