Time Dependent Structure and Spill Measurements of Proton Beams at the CERN SPS

Abstract

For fixed target operation the proton beam is extracted at 14 GeV over 5 successive turns of each 2.1µs from the CPS and injected into the SPS. The current from a secondary emission monitor is sampled every 0.1µs by a charge coupled device. The stored signal is afterwards scanned at a lower frequency and provides an accurate profile evolution during injection. For slow proton beam extraction at 450 GeV a new type of detector has been developed. It uses the properties of the transition radiation created by the beam when traversing a thin aluminium foil. Accurate transverse profiles are obtained by such a detector. The disturbances to the beam are an order of magnitude less than with a classical secondary emission monitor.