Dresden 2013 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 22: Instrumentation

HK 22.6: Vortrag

Montag, 4. März 2013, 18:15–18:30, HSZ-405

ALICE TRD GTU Online Tracking Performance in √s = 7 − 8 TeV pp collisions — •Rettig Felix, Kirsch Stefan, and Lindenstruth Volker — Frankfurt Institute for Advanced Studies, University of Frankfurt

The Transition Radiation Detector provides fast trigger contributions for electron and jet signatures to the ALICE experiment at CERN.

More than 65,000 custom multi-processor modules on-detector identify and parametrize short stiff track segments for a total of 1.2 million analog channels. Within 3µs up to several thousand track segments per event are forwarded to the TRD Global Tracking Unit (GTU).

The GTU consists of 109 FPGA-based processing nodes arranged in three levels. 90 nodes receive data at an aggregate bandwidth of up to 2.16 TBit/s. They perform an online 3D track reconstruction and p_T estimation within 1.2µs. Track information is pushed to 18 sector-level nodes, which run trigger algorithms for single electrons and jets. A top-level node provides the TRD trigger contributions to the central ALICE trigger system within 6µs.

In the past years of continuous operation the TRD online tracking performance was studied for pp and Pb-Pb collisions. A p_T resolution of better than 15-20% over the range from 2 to 10 GeV/c was achieved. In 2012 the jet trigger was put into operation, later two single-electron triggers for heavy flavor and quarkonia studies. Based on the data from pp collisions at √s=7−8 TeV we present the performance of the online tracking and a technical overview of the triggers.