München 2006 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 27: Instrumentation und Anwendungen
HK 27.5: Vortrag
Dienstag, 21. März 2006, 18:00–18:15, H
2nd Level Trigger Performance in HADES. — •Camilla Gilardi — II. Physikalisches Institut, Universität Gießen, Gießen, Germany.
The main purpose of the HADES spectrometer at GSI Darmstadt is the measurements of dilepton decays of light vector mesons.
Since the branching ratio of these decays is of the order of 10−5, in order to collect sufficient statistics an online selective mechanism (trigger) is needed to minimize the amount of collected data.
The trigger of HADES is composed of two levels.
The first level trigger (LVL1) selects the most central collisions, while the second level trigger (LVL2) searches for signatures of dilepton decays as lepton candidates in the RICH, TOF and Pre-shower detector.
In order to select events with lepton pairs, the LVL2 trigger performs pattern recognition to find lepton signatures, and combines the position and angle information for each of these signatures into tracks.
To understand the performance of LVL2, the emulation of the behaviour of every board has to be performed as well as the evaluation of fundamental parameters like efficiency, event reduction and enhancement factor.
Results of this analysis for the reaction 1.8 AGeV Ar + KCl will be shown.
This work has been supported by BMBF, EGS, GSI and the DFG.