• S. Wagner, R. Nibali
  ETH, Zurich
• R. Schmidt, J. Wenninger
  CERN, Geneva

The design and operation of the LHC Machine Protection System (MPS) implicates the trade-off between machine safety and beam availability, defined by MPS reliability in terms of missed emergency beam dumps and false dumps. A generic methodology, including almost 5000 MPS components modeled as individual objects and Monte Carlo simulation, has proved feasible and useful to address that trade-off*. The resulting MPS reliability numbers allow for the comparison of different system configurations with regard to safety and availability. In search of a solution to reduce the simulation time needed for addressing the rare events involved, an analytical description of the model has been developed. Its numerical solution provides an advanced verification of the simulation results and the basis for a rare event approach. The paper introduces the analytical description and the verification of the reliability numbers resulting from the simulations. It specifies to which extent the simulations can be replaced by the analytical model description and where the latter reaches its limits. Furthermore, the meaning of the analytical description as a basis for simulation time reduction is discussed.

*S.Wagner, Balancing Safety and Availability for an Electronic Protection System, ESREL08; S.Wagner, Reliability Analysis of the LHC Machine Protection System: Terminology and Methodology, EPAC08