Heidelberg 2015 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 3: Instrumentation 2
HK 3.4: Talk
Monday, March 23, 2015, 15:30–15:45, M/HS2
Online 4-Dimensional Event Reconstruction in the CBM Experiment — •Valentina Akishina1,2,3 and Ivan Kisel1,2,4 for the CBM collaboration — 1Goethe-Universität Frankfurt, Frankfurt am Main, Germany — 2GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany — 3Joint Institute for Nuclear Research, Dubna, Russia — 4Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
The heavy-ion experiment CBM will focus on the measurement of rare probes at interaction rates up to 10 MHz with data flow of up to 1 TB/s. The free-running data acquisition, delivering a stream of untriggered detector data, requires full event reconstruction and selection to be performed online not only in space, but also in time. The First-Level Event Selection package consists of several modules: track finding, track fitting, short-lived particles finding, event building and event selection.
For track reconstruction the Cellular Automaton (CA) method is used, which allows to reconstruct tracks with high efficiency in a time-slice and perform event building. The time-based CA track finder allows to resolve tracks from a time-slice in event-corresponding groups. The algorithm is intrinsically local and the implementation is both vectorized and parallelized between CPU cores. The CA track finder shows a strong scalability on many-core systems. The speed-up factor of 10.6 on a CPU with 10 hyper-threaded physical cores was achieved.
Supported by FIAS, HICforFAIR and HGS-HIRe for FAIR.