Bonn 2020 – wissenschaftliches Programm
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HK 51.9: Poster
Donnerstag, 2. April 2020, 16:30–18:30, Zelt
Quality Assurance and Spark Detection of GEMs for the ALICE-TPC-Upgrade. — •Thomas Block, Philip Hauer, Markus Ball, and Bernhard Ketzer — University of Bonn, Helmholtz-Institut für Strahlen- und Kernphysik, Bonn, Germany Germany
The MWPC-based readout of the ALICE-TPC is limited to a trigger rate of 3.5 kHz. In order to make full use of the increased luminosity after the Long Shutdown 2, which will result in a minimum-bias interaction rate of 50 kHz, currently an upgrade of the TPC to GEM-based readout chambers is being performed.
For the upgrade more than 800 GEM foils were produced. A rigorous quality assurance scheme was developed and followed to guarantee an excellent quality of the GEMs.
In this poster a summary of the production, the QA scheme, the yields and the most common defects found during chamber construction are presented.
In order to simplify high-voltage tests of GEM foils a webcam-based Spark Detection System (SDS) was developed in Bonn. Discharges, recorded optically with a webcam, can give information about manufacturing defects or dust remnants, which may result in an increased number of discharges and ultimately in short circuits. The design and capabilities of the SDS used for the large ALICE-TPC-GEMs and of a 3D-printable SDS for 10 × 10 cm2 GEMs is presented.
Supported by BMBF.