Keyword: collider
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MOD3I01 Bayesian Reliability Model for Beam Permit System of RHIC at BNL hardware, framework, operation, factory 1
 
  • P. Chitnis
    Stony Brook University, Stony Brook, New York, USA
  • K.A. Brown
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Bayesian Analysis provides a statistical framework for updating prior knowledge as observational evidence is acquired. It can handle complex and realistic models with flexibility. The Beam Permit System (BPS) of RHIC plays a key role in safeguarding against the faults occurring in the collider, hence directly impacts RHIC availability. Earlier a multistate reliability model* was developed to study the failure characteristics of the BPS that incorporated manufacturer and military handbook data. Over the course of its 15 years of operation, RHIC has brought forth operational failure data. This work aims towards the integration of earlier reliability calculations with operational failure data using Bayesian analysis. This paper discusses the Bayesian inference of the BPS reliability using a two-parameter Weibull survival model, with unknown scale and shape parameters. As the joint posterior distribution for Weibull with both parameters unknown is analytically intractable, the Markov Chain Monte Carlo methodology with Metropolis-Hastings algorithm is used to obtain the inference. Selection criteria for the Weibull distribution, prior density and hyperparameters are also discussed.
*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. of ICALEPCS'13, San Francisco, CA.
 
slides icon Slides MOD3I01 [3.929 MB]  
 
MOPGF129 Understanding the Failure Characteristics of the Beam Permit System of RHIC at BNL simulation, ion, kicker, controls 1
 
  • P. Chitnis, T.G. Robertazzi
    Stony Brook University, Stony Brook, New York, USA
  • K.A. Brown
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
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.
 
poster icon Poster MOPGF129 [1.326 MB]  
 
WEPGF036 Data Categorization And Storage Strategies At RHIC Linux, network, operation, real-time 1
 
  • S. Binello, K.A. Brown, T. D'Ottavio, R.A. Katz, J.S. Laster, J. Morris, J. Piacentino
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
This past year the Controls group within the Collider Accelerator Department at Brookhaven National Laboratory replaced the Network Attached Storage (NAS) system that is used to store software and data critical to the operation of the accelerators. The NAS also serves as the initial repository for all logged data. This purchase was used as an opportunity to categorize the data we store, and review and evaluate our storage strategies. This was done in the context of an existing policy that places no explicit limits on the amount of data that users can log, no limits on the amount of time that the data is retained at its original resolution, and that requires all logged data be available in real-time. This paper will describe how the data was categorized, and the various storage strategies used for each category.
 
poster icon Poster WEPGF036 [0.337 MB]