The Beam Energy Tracking System of the LHC Beam Dumping System

The LHC Beam Dumping System (LBDS) of the Large Hadron Collider (LHC), presently under construction at CERN, will be installed around the straight section 6. It comprises per ring 15 horizontally deflecting extraction kickers, followed by 1 quadrupole, 15 vertically deflecting steel septum magnets, 10 dilution kickers and, in a separate cavern several hundred meters away, an external absorber assembly. A beam dump request can occur at any moment during the operation of the collider, from injection at 450 GeV up to top energy at 7 TeV. The Beam Energy Tracking System (BETS) monitors the deflection strength of each active element of the LBDS with respect to the beam energy in order to guarantee the correct extraction trajectory over the complete operational range and under all operational conditions. Its main functions are the acquisition of the beam energy, the generation of the kick strength reference signals for the extraction and dilution kickers, the continuous checking that the kicker high voltage generator capacitor charging voltages follow their references within predefined tolerance windows fixed by the extraction channel aperture, the continuous surveillance that the quadrupole and septum magnet currents are within predefined tolerance windows and the generation of a dump request after detection of and upcoming tracking fault. The beam energy reference is obtained through look-up tables from redundant real time measurements of the current in the LHC main bend dipoles. This paper describes the BETS reviews in detail its different functionality aspects.