Bochum 2018 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 50: Instrumentation XV

HK 50.6: Talk

Thursday, March 1, 2018, 15:30–15:45, Audimax H1

Understanding leakage current of GEMs - quality assurance of GEM foils for the ALICE TPC upgrade — •Pascal Becht for the ALICE collaboration — GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany

The scheduled upgrade of the LHC at CERN, which will result in a higher luminosity and thus a higher heavy-ion interaction rate, made an upgrade of the ALICE experiment’s Time Projection Chamber (TPC) mandatory. During the long shutdown 2 (2019 - 2020) the current Multiwire Proportional Chamber (MWPC) readout will be replaced by Gas Electron Multiplier (GEM) based readout chambers, which are able to provide a continuous readout at rates up to 50 kHz in Pb-Pb collisions.

For that reason the chamber production has already started and makes progress. There an indispensable issue is the extensive quality assurance (QA) done on the GEM foils before they finally get assembled in the chambers. One parameter to quantify the foil’s quality is the leakage current through the foil.

This talk will present the procedure of leakage current tests, done at GSI. Furthermore, the investigation of determining factors of the leakage current through a GEM foil, such as area, pitch size and the hole size, will be discussed.