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HK: Fachverband Physik der Hadronen und Kerne

HK 35: Instrumentation XI

HK 35.7: Vortrag

Mittwoch, 28. Februar 2018, 15:30–15:45, Audimax H1

A model of charge-transfer processes in GEM foils — •Viktor Ratza, Jonathan Ottnad, Markus Ball, and Bernhard Ketzer for the ALICE collaboration — Universität Bonn, Helmholtz-Institut für Strahlen- und Kernphysik, Bonn, Germany

Tracking detectors based on GEM foils are widely used in ongoing experiments and are the choice for numerous upgrades in the near future. An example is the ALICE TPC upgrade at the LHC of CERN where the use of GEM foils will allow the TPC to be employed in a high-rate environment.
In order to optimize and predict the performance of GEM detectors in terms of gain, energy resolution and ion backflow, a good and quantitative understanding of charge-transfer processes of electrons and ions between the individual GEM foils is mandatory. Based on two–dimensional analytic electric flux calculations a model has been established to describe the charge-transfer for GEM foils in terms of the GEM geometry (hole size, pitch and thickness) and the applied electric potentials. Recent advances allow us to calculate the efficiencies in the full range of charge density configurations and as functions of the applied electric fields. Additionally, first three–dimensional approaches will be presented and compared to simulations.

Supported by BMBF.