Studies on potential use and needs of a wideband feedback system for the HL-LHC

Transverse feedback systems are one of the crucial and fundamental devices needed in high brightness proton synchrotrons to ensure a reliable and stable operation. They are used to lock the beam to the reference orbit during injection transient, and also while it is circulating, and thus secure the maintenance of a high beam quality. In particular, the latter use has been important for many of the machines at CERN to prevent single and coupled bunch instabilities from being triggered by impedances or electron clouds. Present systems at CERN are bandwidth limited to 20 MHz at max and are therefore unsuited to be used against the full spectrum of instabilities encountered at the CERN synchrotrons. This report will discuss the ongoing efforts in the R&D of a new class of transverse feedback systems with a widely enlarged bandwidth that should be able to cope with all types of instabilities up to frequencies of several GHz