Beam Loss Monitoring for LHC Machine Protection

Eva Barbara Holzer, Bernd Dehning, Ewald Effnger, Jonathan Emery, Viatcheslav Grishin, C. Hajdú, Stephen Jackson, Christoph Kurfuerst, Aurelien Marsili, Marek Misiowiec, Markus Nagel, Eduardo Nebot Del Busto, Annika Nordt, Chris Roderick, Mariusz Sapinski, Christos Zamantzas

Research output: Contribution to journalConference article

3 Citations (Scopus)


The energy stored in the nominal LHC beams is two times 362 MJ, 100 times the energy of the Tevatron. As little as 1 mJ/cm3 deposited energy quenches a magnet at 7 TeV and 1 J/cm3 causes magnet damage. The beam dumps are the only places to safely dispose of this beam. One of the key systems for machine protection is the beam loss monitoring (BLM) system. About 3600 ionization chambers are installed at likely or critical loss locations around the LHC ring. The losses are integrated in 12 time intervals ranging from 40 μs to 84 s and compared to threshold values defined in 32 energy ranges. A beam abort is requested when potentially dangerous losses are detected or when any of the numerous internal system validation tests fails. In addition, loss data are used for machine set-up and operational verifications. The collimation system for example uses the loss data for set-up and regular performance verification. Commissioning and operational experience of the BLM are presented: The machine protection functionality of the BLM system has been fully reliable; the LHC availability has not been compromised by false beam aborts.

Original languageEnglish
Pages (from-to)2055-2062
Number of pages8
JournalPhysics Procedia
Publication statusPublished - Jan 1 2012
Event2nd International Conference on Technology and Instrumentation in Particle Physics, TIPP 2011 - Chicago, United States
Duration: Jun 9 2011Jun 14 2011


  • beam instrumentation
  • beam loss
  • damage protection
  • machine protection
  • quench protection

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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  • Cite this

    Holzer, E. B., Dehning, B., Effnger, E., Emery, J., Grishin, V., Hajdú, C., Jackson, S., Kurfuerst, C., Marsili, A., Misiowiec, M., Nagel, M., Del Busto, E. N., Nordt, A., Roderick, C., Sapinski, M., & Zamantzas, C. (2012). Beam Loss Monitoring for LHC Machine Protection. Physics Procedia, 37, 2055-2062.