Heidelberg 2015 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 13: Instrumentation 5

HK 13.7: Talk

Monday, March 23, 2015, 18:45–19:00, M/HS2

Charge transfer in Gas Electron Multipliers — •Jonathan Ottnad, Markus Ball, Bernhard Ketzer, Viktor Ratza, and Cina Razzaghi — HISKP, Bonn University, Nussallee 14-16, D-53115 Bonn

In order to efficiently employ a Time Projection Chamber (TPC) at interaction rates higher than ∼ 1 kHz, as foreseen e.g. in the ALICE experiment (CERN) and at CB-ELSA (Bonn), a continuous operation and readout mode is required. A necessary prerequisite is to minimize the space charge coming from the amplification system and to maintain an excellent spatial and energy resolution. Unfortunately these two goals can be in conflict to each other.

Gas Electron Multipliers (GEM) are one candidate to fulfill these requirements. It is necessary to understand the processes within the amplification structure to find optimal operation conditions. To do so, we measure the charge transfer processes in and between GEM foils with different geometries and field configurations, and use an analytical model to describe the results. This model can then be used to predict and optimize the performance.

The talk will give the present status of the measurements and describe the model.

Supported by BMBF and DFG.