Bonn 2010 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 30: Instrumentierung V
HK 30.4: Talk
Tuesday, March 16, 2010, 17:30–17:45, HG VIII
ALICE TRD GTU Tracking and Trigger Performance with First Data — •Stefan Kirsch and Felix Rettig — Kirchhoff-Insitute for Physics, University of Heidelberg
The Transition Radiation Detector of the ALICE experiment is designed
to provide fast trigger contributions for different signature classes as well as
full event information for offline analysis.
A total of 1.2 million analog channels is processed massively parallel
in more than 65 000 multi-chip modules of the front-end electronics.
Pattern matching algorithms are applied to find and parametrize short
stiff track segments.
Up to several thousand track segments are transferred to the second
stage, the Global Tracking Unit (GTU), via 1 080 optical fibres.
The GTU consists of 109 dedicated FPGA-based processing nodes
forming a three-level hierarchy. 90 Track Matching Units perform
online 3D track reconstruction and momentum calculation
based on the track segments within 1.2 µs.
Track information is then forwarded to 18 Supermodule Units for trigger computation.
The top-level Trigger Generation Unit finally delivers the overall
TRD trigger contributions within 6 µs after the collision.
A first analysis of the online tracking performance of the GTU with
early data taken at the LHC and a comparison to detailed hardware simulations
is presented. The performance of first implementations of a single high-pt particle
trigger as well as a jet trigger is evaluated.