CERN’s accelerators at the dawn of a new mandate

Beam is back in the injectors after a stunning effort in Long Shutdown 2 under difficult circumstances. Linac4 is now fully operational and delivering beam to the downstream accelerators. The LHC Injectors Upgrade (LIU) leaves the injectors with many new systems and improvements, and the first benefits are already visible with the recent historic milestones: H- charge exchange injection into the Booster and 2 GeV injection into the PS. More is to come with the restart of the SPS, with the new RF power system, protection devices and numerous other measures paving the way for the proton and ion beams required for the High-Luminosity LHC (HL-LHC).

These achievements are the culmination of more than a decade’s effort in hardware development, prototyping, accelerator physics studies, simulations, controls development, construction, procurement, planning, installation, commissioning and testing of hardware.

And it is a real triumph for the dedication and professionalism of the teams involved and the exercise of technical expertise in conception, construction and operation, as well as the belief that an incredibly challenging large-scale technical set-up such as this can be mastered intellectually. As those involved will testify, it’s not easy, it takes time, and it takes collaboration.

Linac4, the Booster and the PS are highlighted here, but the same approach can be seen across the SPS, AD/ELENA, ISOLDE, n_TOF, the North Area and, of course, the LHC itself, which has seen major programmes of upgrades, maintenance and consolidation, allowing us to look forward to pushing the main dipoles to 7 TeV and a productive Run 3. Getting back to full-scale operation across the complex, and the steady delivery of beams to the extensive user communities, is set to be a great psychological boost following the pandemic.

With the HL-LHC, CERN is looking to secure the high-energy frontier in the medium term, extending the life of the LHC for nearly two decades. The HL-LHC’s 18 work packages draw on expertise across the whole sector and well beyond, with a huge range of technological innovations covering areas as diverse as collimation and crab cavities, cold powering and cryogenics. Key components are the inner triplet quadrupole magnets. The existing triplets have a limited lifespan due to the high level of radiation they receive from luminosity debris.   Their replacement sees the pioneering use of niobium-3 tin (Nb3Sn), a technology that has been developed over the last decade, both at CERN and in the United States, from R&D and prototyping through to series production.

The update of the European Strategy for Particle Physics has entrusted us with exploration of long-term strategic accelerator options, and the associated accelerator R&D. This is quite a programme, covering an FCC feasibility study, an ambitious long-term high-field magnet programme, an international Muon Collider study, and the continued development of CLIC accelerator technology and other high-gradient accelerating structures. AWAKE remains CERN’s flagship in the plasma wakefield acceleration domain, and Physics Beyond Colliders will continue to explore and help develop novel possibilities. Execution of the programme will require careful marshalling of resources and full-scale collaboration with our partners around the world.

It’s hard in a few lines to do justice to the diverse technical capabilities of the Accelerators and Technology sector (ATS).  Deep understanding, experience, expertise, innovation, facilities and manufacturing capability are all present and reflected in a wide-ranging global network of collaborations with institutes and industry. As the importance of sustainability and societal impact grows, we will also continue to incorporate them into our mission. It’s an exciting and challenging time for ATS, and it is an honour for me to lead the sector for the coming five years.

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