Berlin 2005 – scientific programme
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T: Teilchenphysik
T 509: Trigger und DAQ II
T 509.8: Talk
Tuesday, March 8, 2005, 15:50–16:05, TU H4105-4106
ATLAS HLT Steering — •Andrey Belkin — Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, Staudingerweg 7, 55099 Mainz
The ATLAS experiment is being made at the Large Hadron Collider (LHC) at CERN. The LHC is a proton-proton collider with the center of mass energy √s of 14 TeV. The specific of the intended physics is that we need to select rare predicted processes with high efficiency while rejecting much higher-rate background processes over huge number of channels O(108). Decisions must be taken every 25ns at the bunch-crossing rate of 40 MHz; at design luminosity (1034 cm−2 s−1) each bunch-crossing contains about 23 inelastic pp-interactions. On the other hand, the back-end storage rate is limited to approximately 100 Hz (with the average event size of 1 MB) because of computing limitations.
The ATLAS trigger system deals with the high-rate process selection by the three-stage architecture: Level-1, Level-2, and Event Filter. The last two stages (Level-2 and Event Filter) are called High Level Trigger (HLT).
The HLT implements Steering, which is the mechanism to drive the running of certain algorithms on subsets of data as required by a sequence of steps to classify and select events. The current work on the HLT is to test the implemented prototype, particularly Steering mechanisms, and continue development of the final system.