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HK: Fachverband Physik der Hadronen und Kerne
HK 49: Poster
HK 49.31: Poster
Thursday, March 15, 2007, 16:00–17:00, P
Particle identification via engergy loss measurement of the HADES multi-wire drift chambers — •Alexander Schmah1,3, Jochen Markert2, Christian Müntz2, and Joachim Stroth1,2 for the HADES collaboration — 1Gesellschaft für Schwerionenforschung (GSI), Darmstadt — 2Johann Wolfgang Goethe Universität Frankfurt am Main — 3Technische Universität Darmstadt
The HADES tracking system consists of 24 trapezoidal, planar 6-layered low-mass
multi-wire drift chambers (MDC) symmetrically arranged in six sectors, forming
four tracking planes (I-IV) of increasing size.
A method has been developed to derive the energy loss deposited in the drift
cell from the drift signals Time-over-Threshold
ToT. Special attention has to be paid to the unfolding of the
dependencies of the ToT from the track topology, the electric field
and the different cell geometry thus allowing to average over all drift cells
taking part in a reconstructed trajectory. An energy loss resolution of about
10 % is achieved for minimum ionizing particles and 7−8 % for strong
ionizing particles. In combination with the measured momentum it is possible to use
the corrected energy loss signal to directly identify protons and pions. Furthermore
one can use the method to reduce the background in order to select charged kaons.
Mass spectra are presented showing the ability to reconstruct and identify Λ0 and
K+-, K−-, KS0-, φ- mesons by using a combination of time of flight and
energy loss information.
Supported by BMBF