SPS Working Point Studies

The values of the betatron tunes (i.e. the working point) of a circular accelerator are a key feature for the machine operation. This report presents systematic studies, carried out in the SPS, aimed at assessing the single particle beam behaviour as a function of the working point, close to the SPS working point for the LHC beam (Qh=26.13, Qv=26.18). A dynamic scan of the horizontal and vertical tunes during the SPS MD segment allowed us to determine the amplitude of the integer resonance stop-band. Transverse beam emittance evolution, beam losses and resonant driving terms were considered as parameters characterizing the different working points. The measurements were performed with the LHC pilot bunch circulating at constant momentum p=26 GeV/c. The description of the measurement setup will be followed by the discussion of the results. Finally we will propose possible improvements for future studies of the same type.