Münster 2011 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 32: Schwerionenkollisionen und QCD Phasen - Poster
HK 32.1: Poster
Mittwoch, 23. März 2011, 14:00–16:00, Foyer Chemie
Online track reconstruction in the CBM experiment — Ivan Kisel1, Igor Kulakov2,3, Irina Rostovtseva4, and •Maksym Zyzak2,3 — 1GSI Helmholtzzentrum für Schwerionenforschung GmbH — 2Goethe-Universität Frankfurt am Main — 3National Taras Shevchenko University of Kyiv, Ukraine — 4ITEP-Institute for Theoretical and Experimental Physics, Russia
The CBM experiment at FAIR is being designed to study heavy-ion collisions at extremely high interaction rates. For selection purposes full online event reconstruction is required; in this respect, both the speed of the reconstruction algorithms and their efficiency are crucial. The Cellular Automaton (CA) based track finder is used both for the online and offline reconstruction; it is based on the local reconstruction and therefore is robust, fast and easily parallelizable. The algorithm is optimized for the complicated geometry of the detector and takes into account detector inefficiencies. Performed tests have shown robustness of the algorithm against inefficiencies. The CA track finder package includes Kalman filter based track fitter and smoother and deterministic annealing filter. Since modern CPU's are designed for parallel calculations, parallel programming is considered now as one of the most effective ways to increase the speed of programs. The CA based track finder implementation uses SIMD instruction set and multithreading. This allows the utilization of the potential of modern many-core CPU's. Using a Nehalem CPU with 8 cores the CA based track finder demonstrates the maximum throughput of 150 central or 1100 minimum bias events/s.