• A. Nordt, B. Dehning, E. Effinger, J. Emery, E.B. Holzer, D.K. Kramer, E. Lebbos, M. Sapinski, M. Stockner, C. Zamantzas
  CERN, Geneva

The LHC beam loss monitoring system is a safety critical system and ~ 4000 monitors are installed around the ring in order to prevent the superconducting magnets from quenches and protect the machine components from damage. Two different types of beam loss monitors are used: an ionization chamber (IC) and a secondary emission monitor (SEM). The response functions and expected signals have been simulated using Geant4 as well as FLUKA and have been validated and verified with measurements. The Geant4 model of the beam loss monitors has been tested with protons, gammas, neutrons, muon and mixed field beams for steady state and instantaneous losses. Results from the simulations compared to measurement results will be presented. The expected signals for several events (e.g. direct beam impact on collimators, over-injection, high intensity injection) have been checked against real data being taken during the LHC runtime in 2009 and 2010. The very good performance of the system and the agreement with previous simulations will be shown and discussed.