Design and installation of the MSE septum system in the new LSS4 extraction channel of the SPS

For the extraction of the beam from the Super Proton Synchrotron (SPS) to ring 2 of the Large Hadron Collider (LHC) and the CERN Neutrino to Gran Sasso (CNGS) facility, a new fast-extraction system has been installed in the long straight section LSS4 of the SPS. Besides extraction bumpers, enlarged aperture quadrupoles and extraction kicker magnets (MKE), six conventional DC septum magnets (MSE) are used. These magnets are mounted on a single mobile retractable support girder, which is motorised in order to optimise the local SPS aperture during setting up. The MSE septa are connected by a so-called plug-in system to a rigid water-cooled bus bar, which itself is powered by water-cooled cables. In order to avoid destruction of the septum magnet coils by direct impact of the extracted beam, a dilution element (TPSG) has been placed immediately upstream of the first septum coil. The whole system is kept at the required vacuum pressure by ion pumps attached to separate modules (MP). In this note we present the design features of the main equipment elements, describe the control and comprehensive interlock system requirements, and finally report on the details of the magnet cooling system.