Stony Brook University, Stony Brook, New York, USA
BNL, Upton, Long Island, New York, USA
The RHIC Beam Permit System (BPS) monitors the anomalies occurring in the collider and restores the machine to a safe state upon fault detection. The reliability of the BPS thus directly impacts RHIC availability. An analytical multistate reliability model of the BPS has been developed to understand the failure development and propagation over store length variation. BPS has a modular structure. The individual modules have joint survival distributions defined by competing risks with exponential lifetimes. Modules differ in functionality and input response. The overall complex behavior of the system is analyzed by first principles for different failure/success states of the system. The model structure changes according to the type of scenario. The analytical model yields the marginal survival distribution for each scenario versus different store lengths. Analysis of structural importance and interdependencies of modules is also examined. A former Monte Carlo model* is used for the verification of the analytical model for a certain store length. This work is next step towards building knowledge base for eRHIC design by understanding finer failure characteristics of the BPS.
*P. Chitnis et al., 'A Monte Carlo Simulation Approach to the Reliability Modeling of the Beam Permit System of Relativistic Heavy Ion Collider (RHIC) at BNL', Proc. ICALEPCS'13, San Francisco, CA.
