The ALICE TPC upgrade - From R&D to Installation

by Dr Markus Ball (University of Bonn)

Thursday 6 Jun 2019, 14:00 → 15:00 Portugal

Sala de Conferências (Departamento de Física)

With the ongoing upgrade of the ALICE (A Large Ion Collider Experiment at CERN) Time Projection Chamber the current readout technology is replaced by a Gas Electron Multiplier (GEM) - based readout technology. This allows a continuous operation at high interaction rates up to 50kHz in Pb-Pb collisions. A stack of four GEM stages with specific field field configuration was chosen to achieve a suppression of the ion backflow below 1 %, while maintaining a sufficient energy resolution below 12 % for a Fe-55 source. The discharge probability was shown to be comparable to standard triple GEM detectors in low discharge settings. From 2017 to 2018 the production of 40 Inner Readout Chambers (IROC) and 40 Outer Readout Chambers has taken place.
The work flow of the chamber production contained the production of GEM foils, their quality assurance, the framing of the GEMs as well as the assembly and quality assurance of the Readout Chambers. Several chambers were tested under LHC conditions in close vicinity of the ALICE experiment. Currently the the installation and the replacement of the MWPC with GEM chambers is ongoing.
In early 2021 the TPC will be brought back into the experiment. The new data taking will start then in 2022.