Heidelberg 2015 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 2: Instrumentation 1

HK 2.7: Vortrag

Montag, 23. März 2015, 16:15–16:30, M/HS1

Characterization of a hybrid GEM-Micromegas detector with respect to its application in a continuously operating TPC — •Viktor Ratza, Markus Ball, Bernhard Ketzer, and Jonathan Ottnad — Helmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Germany

In the context of the upgrade of the LHC during the second long shutdown the interaction rate of the ALICE experiment will be increased up to 50 kHz for Pb-Pb collisions. As a consequence, a continuous operation of the Time Projection Chamber (TPC) will be required. To handle the expected increase of space-charge distortions without a gating grid, the ion backflow of the charge amplification system has to be significantly reduced, maintaining at the same time an excellent detector performance and stability. As default solution an amplification system with four Gaseous Electron Multipliers (GEM) has been selected. As an alternative approach a hybrid micropattern gaseous detector consisting of two GEMs and a Micromegas (MM) is under investigation. Due to the geometric and electrostatic structure of the MM the ion backflow suppression capability is superior to a single GEM. The two GEM stages in front of the MM are installed to further reduce the ion backflow and to keep the discharge probability of the device at a reasonable level. The current results and the status of the study will be presented.

Supported by BMBF and EU.