Frankfurt 2014 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 21: Instrumentierung
HK 21.1: Group Report
Tuesday, March 18, 2014, 14:00–14:30, HZ 8
ALICE TRD On-line Tracking and Trigger Performance — •Felix Rettig1, Jochen Klein2, and Uwe Westerhoff3 for the ALICE collaboration — 1FIAS, Universität Frankfurt — 2Physikalisches Institut, Universität Heidelberg — 3IKP, Universität Münster
The Transition Radiation Detector (TRD) in A Large Ion Collider Experiment (ALICE) at the LHC consists of 6 layers of tracking chambers and covers a pseudo-rapidity range of ±0.9. Presently, 13 out of 18 azimuthal sectors are installed. The completion is planned during the first long LHC shutdown in 2013/14.
We will discuss how a hardware Level-1 trigger, about 8 us after an interaction, is derived by this detector. Chamber-wise track segments from fast on-detector reconstruction are read out with position, angle and PID information. In the Global Tracking Unit, these tracklets are merged to a track and used for the reconstruction of transverse momenta and electron identification of individual tracks. These tracks form the basis for versatile and flexible trigger conditions, s.a. single high-pt hadron, single high-pt electron, di-electron (J/Psi, Upsilon) and at least n close high-pt tracks (jet).
After a period of minimum bias data-taking, rare triggers are now used in ALICE. The TRD contributes a jet trigger and two electron triggers. We will discuss the tracking performance and report on our experience on the TRD-based triggers.