Design of beam halo monitor for CMS

Styliani Orfanelli, Anne Dabrowski, Rob Loos, Fabrizio Fabbri, Alessandro Montanari, Nicolo Tosi, Alexey Finkel, Roger Rusack, David P. Stickland

Research output: Contribution to journalConference articlepeer-review


A fast and directional monitoring system for the CMS experiment is designed to provide an online, bunch-by-bunch measurement of beam background induced by beam halo interactions, separately for each beam. The background detection is based on Cherenkov radiation produced in synthetic fused silica read out by a fast, UV sensitive photomultiplier tube. Twenty detector units per end will be azimuthally distributed around the rotating shielding of CMS, covering ∼408 cm2 at 20.6m from the interaction point, at a radius of ∼180 cm. The directional and fast response of the system allows the discrimination of the background particles from the dominant flux in the cavern induced by pp collision debris, produced within the 25 ns bunch spacing. A robust multi-layered shielding will enclose each detector unit to protect the photomultiplier tube from the magnetic field and to eliminate the occupancy from low energy particles. The design of the front-end units is validated by experimental results. An overview of the new system to be integrated in CMS during the current shutdown of LHC will be presented, and its perspective for monitoring in High Luminosity LHC.

Original languageEnglish (US)
Article number352
JournalProceedings of Science
StatePublished - 2014
Event3rd Technology and Instrumentation in Particle Physics Conference, TIPP 2014 - Amsterdam, Netherlands
Duration: Jun 2 2014Jun 6 2014

All Science Journal Classification (ASJC) codes

  • General


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