Author/Authors :
Andronic، نويسنده , , A. and Appelsh?user، نويسنده , , H. -P Blume، نويسنده , , C. and Braun-Munzinger، نويسنده , , P. and Bucher، نويسنده , , D. Shallin Busch، نويسنده , , O. and C?t?nescu، نويسنده , , V. and Ciobanu، نويسنده , , M. and Daues، نويسنده , , H. and Emschermann، نويسنده , , D. and Fateev، نويسنده , , O. and Foka، نويسنده , , Y. and Garabatos، نويسنده , , C. and Gunji، نويسنده , , T. and Herrmann، نويسنده , , N. and Inuzu، نويسنده ,
Abstract :
Using prototype modules of the ALICE Transition Radiation Detector (TRD) we investigate space-charge effects and the dependence of the pion rejection performance on the incident angle of the ionizing particle. The average pulse height distributions in the drift chambers operated with the Xe,CO2(15%) mixture provide quantitative information on the gas gain reduction due to space charge accumulating during the drift of the primary ionization. Our results demonstrate that the pion rejection performance of a TRD is better for tracks which are not at normal incidence to the anode wires. We present detailed simulations of detector signals, which reproduce the measurements and lend strong support to our interpretation of the measurements in terms of space-charge effects.
Keywords :
Transition radiation detector , Electron/pion identification , Drift chambers , Pulse height measurements , Space charge
