Signal Analysis and Detection for the BPMs of the LHC Hollow Electron Lens

The Large Hadron Collider (LHC) at CERN will be equipped with two hollow electron lenses (HEL) for the high luminosity upgrade, which allow for scraping of the LHC proton or ion beams transverse tails by overlapping a coaxial hollow electron beam over a 3 m length. A precise alignment of the two beams is essential for the HEL functionality, the bunched LHC hadron beam of up to 7 TeV beam energy, and the non-relativistic, DC-like electron hollow beam of 10 keV energy. The absolute and relative transverse positions of both beams will be monitored by two stripline beam position monitors (BPM), located in the HEL, and the pickup signal processed by a narrowband signal detection system. This paper summarizes the analysis of the expected proton and electron beam signals, including laboratory measurements, with aim of a narrowband diode-detection read-out electronics as BPM signal processor.