Bochum 2009 – scientific programme
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HK: Fachverband Hadronen und Kerne
HK 9: Accelerators and Instrumentation I
HK 9.3: Talk
Monday, March 16, 2009, 14:45–15:00, H-ZO 80
Study of the effect of data compression on the position resolution of the ALICE TRD — •Svenja Wulff — Institut für Kernphysik, WWU Münster, Germany
The Transition Radiation Detector (TRD) of ALICE at the Large Hadron Collider consists of 540 Xe gas-filled drift chambers with a total active area of roughly 700 m2 read out via 1.2 million electronic channels. To keep the readout time as short as possible and to optimize the usage of mass storage the data is compressed on the fly. One method is the so-called ‘zero suppression‘. The Tracklet Processing Chip is the component of the TRD front-end electronics and performs digital filtering of the raw data including baseline subtraction, tail cancellation and corrections of gain variations. For the purpose of zero suppression it is equipped with a mechanism to mark channels for read out based on three criteria to avoid that channels are read out containing fluctuations around the baseline only.
A systematic study of the effect of zero suppression with various sets of criteria on the event size and on the position resolution of the read out chambers will be presented. Cosmic rays have been used for this study.