Measurements made in the SPS with a Rest Gas Profile Monitor by collecting Electrons

Measurements have regularly been performed during the 1999 run, using the Rest Gas Monitor installed in the SPS. The exploited signal resulted from electrons produced by ionisation of the rest gas during the circulating beam passage. A magnetic field parallel to the electric extraction field was applied to channel the electrons. Proton beam horizontal transverse distributions were recorded during entire SPS acceleration cycles, between 14 GeV/c and 450 GeV/c and for different beam structures and bunch intensities. The influence of several parameters on the measured beam profiles was investigated. Results are presented and analysed in order to determine the performance that can be expected.