BLM Threshold Strategy (UFOs and Quenches)

Abstract

The interaction of the LHC’s proton beam with falling macroparticles (dust) in the beam tube causes beam losses with durations ranging from tens of microseconds to several milliseconds. After the long shutdown, the beam energy will be increased from 4 towards 6.5 TeV, as a consequence of which some of these beam-particle interactions, colloquially called “UFOs”, are predicted to cause quenches in superconducting magnets. In-depth experimental and numerical studies have been performed to make the most efficient use possible of the LHCs beam-loss monitoring (BLM) system to minimize the number of quenches, while keeping the number of avoidable beam dumps due to the BLM system to a minimum. The results of these studies are presented here, as well as preliminary strategies for the setting of BLM thresholds for the protection of warm magnets and collimators.