ACCURACY OF THE SPS TRANSVERSE EMITTANCE MONITORS

A campaign of studies and measurements has been carried out with the aim of establishing the SPS transverse profile monitors resolution, reproducibility and accuracy. The studies regarded systematic dependencies of the SPS Wire Scanner (WS) monitors on the operation setups and on the beam parameters, like beam intensity, bunch spacing and beam size. The emittance increase due to multiple Coulomb scattering during the linear WS operation has been measured and compared with the theoretical model prediction. Numerical simulations estimate the errors introduced by the limited resolution of the imaging systems and by excessive electronic noise of the detectors. The experimental measurements have been carried out with a wide range of beams, from the low intensity pilot bunch to the LHC nominal beam. At first the different SPS WS are compared during simultaneous measurements. The SPS IPM vertical profiles have been compared to the WS while tracking the beam emittance from 26 to 450 GeV. The IPM resolution improvements from 2003 to 2004 are pointed out.