The cms trigger supervisor: control and hardware monitoring system of the cms level-1 trigger at cern
- Autores: Ildefons Magrans de Abril
- Directores de la Tesis: Claudia-elisabeth Wulz (dir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2008
- Idioma: español
- Tribunal Calificador de la Tesis: Peter Wesley-Smith (presid.), David Beltrán Chiva (secret.), Jorge Fernández de Troconiz (voc.), Basile Getie (voc.), Andreu Pacheco Pages (voc.)
- Materias:
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- Resumen
The experiments CMS (Compact Muon Solenoid) and ATLAS (A Toroidal LHC Apparatus) at the Large Hadron Collider (LHC) are the greatest exponents of the rising complexity in High Energy Physics (HEP) data handling instrumentation. Tens of millions of readout channels, tens of thousands of hardware boards and the same order of connections are figures of merit. However, the hardware volume is not the only complexity dimension, the unprecedented large number of research institutes and scientists that form the international collaborations, and the long design, development, commissioning and operational phases are additional factors that must be taken into account.
The Level-1 (L1) trigger decision loop is an excellent example of these difficulties. This system is based on a pipelined logic destined to analyze without deadtime the data from each LHC bunch crossing occurring every 25 ns, using special coarsely segmented trigger data from the detectors. The L1 trigger is responsible for reducing the rate of accepted crossings to below 100 kHz. While the L1 trigger is taking its decision the full high-precision data of all detector channels are stored in the detector front-end buffers, which are only read out if the event is accepted. The Level-1 Accept (L1 A) decision is communicated to the sub-detectors through the Timing, Trigger and Control (TTC) system. The L1 decision loop hardware system was built by more than ten research institutes with a development and construction period of nearly ten years, featuring more than fifty VME crates, and thousands of boards and connections.
In this context, it is mandatory to provide software tools that ease integration and the short, medium and long term operation of the experiment. This research work proposes solutions, based on web services technologies, to simplify the implementation and operation of software control systems to manage hardware devices for HEP experiments. The main contribution of this work is the design and development of a hardware management system intended to enable the operation and integration of the L1 decision loop of the CMS experiment (CMS Trigger Supervisor, TS).
The TS conceptual design proposes a hierarchical distributed system which fits the web services based model of the CMS Online Software Infrastructure (OSWl) well. The functional scope of this system covers the configuration, testing and monitoring of the L1 decision loop hardware, and its interaction with the overall CMS experiment control system and the rest of the experiment. Together with the technical design aspects, the project organization strategy is discussed.
The main topic follows an initial investigation about the usage of the extended Markup Language (XML) as uniform data representation format for a software environment to implement hardware management systems for HEP experiments. This model extends the usage of XML beyond the boundaries of the control and monitoring related data and proposes its usage also for the code. This effort, carried out in the context of the CMS Trigger and Data Acquisition project, improved the overall team knowledge on XML technologies, created a pool of ideas and helped to anticipate the main TS requirements and architectural concepts.
