Erlangen 2001 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 42: Instrumentation und Anwendungen VII
HK 42.6: Vortrag
Donnerstag, 22. März 2001, 15:45–16:15, A
ALICE TRD: Results from Prototype Tests — •Anton Andronic — GSI Darmstadt
The Transition Radiation Detector (TRD) was designed to provide for the ALICE detector at LHC a pion rejection factor of at least one hundred for momenta above 2 GeV/c. It will allow, in conjunction with other ALICE detectors, to study various aspects of dielectron physics, among them the production of quarkonia like J/ψ, ψ′ and the members of the Υ family, as well as the production of open charm and beauty. The TRD has to work in the environment of unprecedented multiplicities expected in Pb+Pb collisions at LHC. Under such conditions, the required parameters of the detector are no less impressive: up to 1.2 million channels will be readout via Flash-ADCs in a specially developed data chain. With six layers covering the interaction point at radial distances between 2.9 and 3.7 meters, the ALICE TRD will be the largest of such detectors for a collider experiment. We have tested a prototype of the TRD composed of a radiator (different types have been studied, made of foils, fibres or foams) and a drift chamber with pad readout, filled with the Xe,CH4(10%) gas mixture. The tests have been performed using the secondary pion beam (with natural electron contamination) at GSI Darmstadt with momenta between 0.6 and 2.0 GeV/c. Different methods of analysis are used for pion rejection studies, with the goal to optimize the final configuration of the detector. Exploiting the information on energy deposit over the drift region of 3 cm in a likelihood method, we have achieved pion rejection factors of about 500 for momenta around 2 GeV/c. The results presented are of general significance for TRDs.