Bonn 2010 – wissenschaftliches Programm
HK 30.1: Gruppenbericht
Dienstag, 16. März 2010, 16:30–17:00, HG VIII
First Collisions with the ALICE High-Level Trigger — •Jochen Thäder — Frankfurt Institute for Advanced Studies, Universität Frankfurt
The High-Level Trigger (HLT) for the heavy ion experiment ALICE is a high performance PC cluster of several hundreds of nodes, which has to reduce the data rate of up to 25 GB/s to at most 1.25 GB/s before permanent storage. In the 2008/2009 shutdown the HLT has finalized the hardware setup for proton proton (pp) collisions. The first 200 nodes have been installed and all ALICE sub detectors have been connected. Furthermore the installation of the full GigaBit Ethernet network and the InfiniBand backbone network has been completed and the first GPU co-processors have been installed.The HLT was running full on-line reconstruction during the ALICE commissioning with cosmics. Furthermore the HLT cosmics trigger has been exercised to enhance the L0 cosmic triggers and reduce the amount of stored raw data. During the first collisions of the LHC as well as in the normal pp data-taking the HLT was also performing full on-line reconstruction and vertex finding to give a fast feedback on the beam position.
The ALICE HLT performance results obtained during the commissioning phase and during the first ALICE data taking with beam at the LHC will be presented in this talk.
Work on the ALICE High-Level Trigger has been financed by the German Federal Ministry of Education and Research (BMBF) as part of its program "Förderschwerpunkt Hadronen- und Kernphysik - Großgeräte der physikalischen Grundlagenforschung".