Author: De Cataldo, G.
Paper Title Page
WEPMU026 Protecting Detectors in ALICE 1122
 
  • M. Lechman, A. Augustinus, P.Ch. Chochula, G. De Cataldo, A. Di Mauro, L.S. Jirdén, A.N. Kurepin, P. Rosinský, H. Schindler
    CERN, Geneva, Switzerland
  • A. Moreno
    Universidad Politécnica de Madrid, E.T.S.I Industriales, Madrid, Spain
  • O. Pinazza
    INFN-Bologna, Bologna, Italy
 
  ALICE is one of the big LHC experiments at CERN in Geneva. It is composed of many sophisticated and complex detectors mounted very compactly around the beam pipe. Each detector is a unique masterpiece of design, engineering and construction and any damage to it could stop the experiment for months or even for years. It is therefore essential that the detectors are protected from any danger and this is one very important role of the Detector Control System (DCS). One of the main dangers for the detectors is the particle beam itself. Since the detectors are designed to be extremely sensitive to particles they are also vulnerable to any excess of beam conditions provided by the LHC accelerator. The beam protection consists of a combination of hardware interlocks and control software and this paper will describe how this is implemented and handled in ALICE. Tools have also been developed to support operators and shift leaders in the decision making related to beam safety. The gained experiences and conclusions from the individual safety projects are also presented.  
poster icon Poster WEPMU026 [1.561 MB]  
 
THBHAUST02 The Wonderland of Operating the ALICE Experiment 1182
 
  • A. Augustinus, P.Ch. Chochula, G. De Cataldo, L.S. Jirdén, A.N. Kurepin, M. Lechman, O. Pinazza, P. Rosinský
    CERN, Geneva, Switzerland
  • A. Moreno
    Universidad Politécnica de Madrid, E.T.S.I Industriales, Madrid, Spain
 
  ALICE is one of the experiments at the Large Hadron Collider (LHC), CERN (Geneva, Switzerland). Composed of 18 sub-detectors each with numerous subsystems that need to be controlled and operated in a safe and efficient way. The Detector Control System (DCS) is the key for this and has been used by detector experts with success during the commissioning of the individual detectors. With the transition from commissioning to operation more and more tasks were transferred from detector experts to central operators. By the end of the 2010 datataking campaign the ALICE experiment was run by a small crew of central operators, with only a single controls operator. The transition from expert to non-expert operation constituted a real challenge in terms of tools, documentation and training. In addition a relatively high turnover and diversity in the operator crew that is specific to the HEP experiment environment (as opposed to the more stable operation crews for accelerators) made this challenge even bigger. This paper describes the original architectural choices that were made and the key components that allowed to come to a homogeneous control system that would allow for efficient centralized operation. Challenges and specific constraints that apply to the operation of a large complex experiment are described. Emphasis will be put on the tools and procedures that were implemented to allow the transition from local detector expert operation during commissioning and early operation, to efficient centralized operation by a small operator crew not necessarily consisting of experts.  
slides icon Slides THBHAUST02 [1.933 MB]  
 
MOPKN015 Managing Information Flow in ALICE 124
 
  • O. Pinazza
    INFN-Bologna, Bologna, Italy
  • A. Augustinus, P.Ch. Chochula, L.S. Jirdén, A.N. Kurepin, M. Lechman, P. Rosinský
    CERN, Geneva, Switzerland
  • G. De Cataldo
    INFN-Bari, Bari, Italy
  • A. Moreno
    Universidad Politécnica de Madrid, E.T.S.I Industriales, Madrid, Spain
 
  ALICE is one of the experiments at the Large Hadron Collider (LHC), CERN (Geneva, Switzerland). The ALICE detector control system is an integrated system collecting 18 different subdetectors' controls and general services and is implemented using the commercial SCADA package PVSS. Information of general interest, beam and ALICE condition data, together with data related to shared plants or systems, are made available to all the subsystems through the distribution capabilities of PVSS. Great care has been taken during the design and implementation to build the control system as a hierarchical system, limiting the interdependencies of the various subsystems. Accessing remote resources in a PVSS distributed environment is very simple, and can be initiated unilaterally. In order to improve the reliability of distributed data and to avoid unforeseen dependencies, the ALICE DCS group has enforced the centralization of the publication of global data and other specific variables requested by the subsystems. As an example, a specific monitoring tool will be presented that has been developed in PVSS to estimate the level of interdependency and to understand the optimal layout of the distributed connections, allowing for an interactive visualization of the distribution topology.  
poster icon Poster MOPKN015 [2.585 MB]  
 
MOPKN018 Computing Architecture of the ALICE Detector Control System 134
 
  • P. Rosinský, A. Augustinus, P.Ch. Chochula, L.S. Jirdén, M. Lechman
    CERN, Geneva, Switzerland
  • G. De Cataldo
    INFN-Bari, Bari, Italy
  • A.N. Kurepin
    RAS/INR, Moscow, Russia
  • A. Moreno
    Universidad Politécnica de Madrid, E.T.S.I Industriales, Madrid, Spain
  • O. Pinazza
    INFN-Bologna, Bologna, Italy
 
  The ALICE Detector Control System (DCS) is based on a commercial SCADA product, running on a large Windows computer cluster. It communicates with about 1200 network attached devices to assure safe and stable operation of the experiment. In the presentation we focus on the design of the ALICE DCS computer systems. We describe the management of data flow, mechanisms for handling the large data amounts and information exchange with external systems. One of the key operational requirements is an intuitive, error proof and robust user interface allowing for simple operation of the experiment. At the same time the typical operator task, like trending or routine checks of the devices, must be decoupled from the automated operation in order to prevent overload of critical parts of the system. All these requirements must be implemented in an environment with strict security requirements. In the presentation we explain how these demands affected the architecture of the ALICE DCS.  
 
MOPMS031 Did We Get What We Aimed for 10 Years Ago? 397
 
  • P.Ch. Chochula, A. Augustinus, L.S. Jirdén, A.N. Kurepin, M. Lechman, P. Rosinský
    CERN, Geneva, Switzerland
  • G. De Cataldo
    INFN-Bari, Bari, Italy
  • A. Moreno
    Universidad Politécnica de Madrid, E.T.S.I Industriales, Madrid, Spain
  • O. Pinazza
    INFN-Bologna, Bologna, Italy
 
  The ALICE Detector Control System (DCS) is in charge of control and operation of one of the large high energy physics experiments at CERN in Geneva. The DCS design which started in 2000 was partly inspired by the control systems of the previous generation of HEP experiments at the LEP accelerator at CERN. However, the scale of the LHC experiments, the use of modern, "intelligent" hardware and the harsh operational environment led to an innovative system design. The overall architecture has been largely based on commercial products like PVSS SCADA system and OPC servers extended by frameworks. Windows has been chosen as operating system platform for the core systems and Linux for the frontend devices. The concept of finite state machines has been deeply integrated into the system design. Finally, the design principles have been optimized and adapted to the expected operational needs. The ALICE DCS was designed, prototyped and developed at the time, when no experience with systems of similar scale and complexity existed. At the time of its implementation the detector hardware was not yet available and tests were performed only with partial detector installations. In this paper we analyse how well the original requirements and expectations set ten years ago comply with the real experiment needs after two years of operation. We provide an overview of system performance, reliability and scalability. Based on this experience we assess the need for future system enhancements to take place during the LHC technical stop in 2013.  
poster icon Poster MOPMS031 [5.534 MB]  
 
WEPKN019 A Programmable Logic Controller-Based System for the Recirculation of Liquid C6F14 in the ALICE High Momentum Particle Identification Detector at the Large Hadron Collider 745
 
  • I. Sgura, G. De Cataldo, A. Franco, C. Pastore, G. Volpe
    INFN-Bari, Bari, Italy
 
  We present the design and the implementation of the Control System (CS) for the recirculation of liquid C6F14 (Perfluorohexane) in the High Momentum Particle Identification Detector (HMPID). The HMPID is a sub-detector of the ALICE experiment at the CERN Large Hadron Collider (LHC) and it uses liquid C6F14 as Cherenkov radiator medium in 21 quartz trays for the measurement of the velocity of charged particles. The primary task of the Liquid Circulation System (LCS) is to ensure the highest transparency of C6F14 to ultraviolet light by re-circulating the liquid through a set of special filters. In order to provide safe long term operation a PLC-based CS has been implemented. The CS supports both automatic and manual operating modes, remotely or locally. The adopted Finite State Machine approach minimizes the possible operator errors and provides a hierarchical control structure allowing the operation and monitoring of a single radiator tray. The LCS is protected against anomalous working conditions by both active and passive systems. The active ones are ensured via the control software running in the PLC whereas the human interface and data archiving are provided via PVSS, the SCADA framework which integrates the full detector control. The LCS under CS control has been fully commissioned and proved to meet all requirements, thus enabling HMPID to successfully collect the data from the first LHC operation..  
poster icon Poster WEPKN019 [1.270 MB]