Stony Brook University, Stony Brook, New York, USA
BNL, Upton, Long Island, New York, USA
The RHIC Beam Permit System (BPS) monitors the health of RHIC subsystems and takes active decisions regarding beam-abort and magnet power dump, upon a subsystem fault. The reliability of BPS directly impacts the RHIC downtime, and hence its availability. This work assesses the probability of BPS failures that could lead to substantial downtime. A fail-safe condition imparts downtime to restart the machine, while a failure to respond to an actual fault can cause potential machine damage and impose significant downtime. This paper illustrates a modular multistate reliability model of the BPS, with modules having exponential lifetime distributions. The model is based on the Competing Risks Theory with Crude Lifetimes, where multiple failure modes compete against each other to cause a final failure, and simultaneously influence each other. It is also dynamic in nature as the number of modules varies based on the fault trigger location. The model is implemented as a Monte Carlo simulation in Java, and analytically validated. The eRHIC BPS will be an extension of RHIC BPS. This analysis will facilitate building a knowledge base rendering intelligent decision support for eRHIC BPS design.
Stony Brook University, Stony Brook, New York, USA
BNL, Upton, Long Island, New York, USA
The RHIC Beam Permit System (BPS) plays a key role in safeguarding against the anomalies developing in the collider during a run. The BPS collects RHIC subsystem statuses to allow the beam entry and its existence in the machine. The building blocks of BPS are Permit Module (PM) and Abort Kicker Module (AKM), which incorporate various electronic boards based on VME specification. This paper presents a quantitative Fault Tree Analysis (FTA) of the PM and AKM, yielding the hazard rates of three top failures that are potential enough to cause a significant downtime of the machine. The FTA helps tracing down the top failure of the module to a component level failure (such as an IC or resistor). The fault trees are constructed for all module variants and are probabilistically evaluated using an analytical solution approach. The component failure rates are calculated using manufacturer datasheets and MIL-HDBK-217F. The apportionment of failure modes for components is calculated using FMD-97. The aim of this work is to understand the importance of individual components of the RHIC BPS regarding its reliable operation, and evaluate their impact on the operation of BPS.