Speaker
Description
During the long shutdown 2 of the LHC, the ALICE Time Projection Chamber (TPC) was upgraded in order to cope with the increased Pb-Pb interaction rate of 50 kHz planned for Run 3. The MWPC-based amplification system was replaced by Gas Electron Multipliers (GEM). These avoid the long dead time caused by the ion gating grid of the MWPC, and hence allow for a continuous readout. At the same time, also the front-end and readout electronics was replaced.
In August 2020, the TPC was moved back to its position at LHC interaction point 2 and an extensive commissioning program was started. It includes measurements of laser tracks, cosmic particles, the irradiation of the TPC with an X-ray source and the flushing of the chamber with radioactive Kr to carry out a pad-by-pad gain calibration. During this measurement campaign, the TPC operated at nominal conditions and the continuous readout capability was tested successfully.
The talk will summarise the performance and challenges during the commissioning phase. Furthermore, the first results of the operation with p-p collisions and plans for the future will be discussed.
| Primary experiment | ALICE |
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