Frankfurt 2014 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 21: Instrumentierung

HK 21.1: Gruppenbericht

Dienstag, 18. März 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.