RF Group Annual Report 2011

The highest priority for the RF group in 2011 was to contribute to a successful physics run of the LHC. This comprises operation of the superconducting 400 MHz accelerating system (ACS) and the transverse damper (ADT) of the LHC itself, but also all the individual links of the injector chain upstream of the LHC – Linac2, the PSB, the PS and the SPS – don’t forget that it is RF in all these accelerators that truly accelerates! A large variety of RF systems had to operate reliably, often near their limit. New tricks had to be found and implemented to go beyond limits; not to forget the equally demanding operation with Pb ions using in addition Linac3 and LEIR. But also other physics users required the full attention of the RF group: CNGS required in 2011 beams with very short, intense bunches, AD required reliable deceleration and cooling of anti-protons, Isolde the post-acceleration of radioactive isotopes in Rex, just to name a few. In addition to the supply of beams for physics, the RF group has a number of projects and studies to look after: CLIC studies the feasibility of a normal-conducting linear collider and probes feasibility of extreme high-gradient X-band acceleration as well as a number of novel concepts, SPL is a superconducting linear proton or H˗ accelerator with large average beam power, HIE-Isolde is extending the reach of Isolde to even higher energy for radioactive isotopes with superconducting (SC) quarter-wave resonators. For HL-LHC, the LHC luminosity upgrade project, the RF group looks at novel, compact crab cavities required to bring colliding bunches well on top when using a crossing angle, Linac4 is the on-going project for a 160 MeV H˗ injector to eventually replace Linac2 and LIU, the LHC Injector Upgrade project, focuses on targeted upgrades of the other identified RF bottle-necks of the injectors, in particular in the PSB and the SPS. Many of the CERN accelerators are very old – older than the people operating them; to keep them running reliably requires substantial maintenance and consolidation work, which has to be taken very seriously. Taking good care of these old machines and teaching them new tricks, adapting them to a changing environment and concepts nicely fits between operation and maintenance on one side, upgrades and new projects on the other.