Author: Magnin, N.
Paper Title Page
WEPMU019 First Operational Experience with the LHC Beam Dump Trigger Synchronisation Unit 1100
  • A. Antoine, C. Boucly, P. Juteau, N. Magnin, N. Voumard
    CERN, Geneva, Switzerland
  Two LHC Beam Dumping Systems (LBDS) remove the counter-rotating beams safely from the collider during setting up of the accelerator, at the end of a physics run and in case of emergencies. Dump requests can come from 3 different sources: the machine protection system in emergency cases, the machine timing system for scheduled dumps or the LBDS itself in case of internal failures. These dump requests are synchronised with the 3 μs beam abort gap in a fail-safe redundant Trigger Synchronisation Unit (TSU) based on Digital Phase Lock Loops (DPLL), locked onto the LHC beam revolution frequency with a maximum phase error of 40 ns. The synchronised trigger pulses coming out of the TSU are then distributed to the high voltage generators of the beam dump kickers through a redundant fault-tolerant trigger distribution system. This paper describes the operational experience gained with the TSU since their commissioning with beam in 2009, and highlights the improvements which have been implemented for a safer operation. This includes an increase of the diagnosis and monitoring functionalities, a more automated validation of the hardware and embedded firmware before deployment, or the execution of a post-operational analysis of the TSU performance after each dump action. In the light of this first experience the outcome of the external review performed in 2010 is presented. The lessons learnt on the project life-cycle for the design of mission critical electronic modules are discussed.  
poster icon Poster WEPMU019 [1.220 MB]  
WEPMU023 External Post-Operational Checks for the LHC Beam Dumping System 1111
  • N. Magnin, V. Baggiolini, E. Carlier, B. Goddard, R. Gorbonosov, D. Khasbulatov, J.A. Uythoven, M. Zerlauth
    CERN, Geneva, Switzerland
  The LHC Beam Dumping System (LBDS) is a critical part of the LHC machine protection system. After every LHC beam dump action the various signals and transient data recordings of the beam dumping control systems and beam instrumentation measurements are automatically analysed by the eXternal Post-Operational Checks (XPOC) system to verify the correct execution of the dump action and the integrity of the related equipment. This software system complements the LHC machine protection hardware, and has to ascertain that the beam dumping system is ‘as good as new’ before the start of the next operational cycle. This is the only way by which the stringent reliability requirements can be met. The XPOC system has been developed within the framework of the LHC “Post-Mortem” system, allowing highly dependable data acquisition, data archiving, live analysis of acquired data and replay of previously recorded events. It is composed of various analysis modules, each one dedicated to the analysis of measurements coming from specific equipment. This paper describes the global architecture of the XPOC system and gives examples of the analyses performed by some of the most important analysis modules. It explains the integration of the XPOC into the LHC control infrastructure along with its integration into the decision chain to allow proceeding with beam operation. Finally, it discusses the operational experience with the XPOC system acquired during the first years of LHC operation, and illustrates examples of internal system faults or abnormal beam dump executions which it has detected.  
poster icon Poster WEPMU023 [1.768 MB]