Mainz 2022 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 6: Instrumentation III

HK 6.1: Vortrag

Montag, 28. März 2022, 14:00–14:15, HK-H5

Gain Calibration of the Upgraded ALICE TPC — •Philip Hauer for the ALICE collaboration — Helmholtz-Institut für Strahlen- und Kernphysik – Universität Bonn

For the upcoming Run 3 of the Large Hadron Collider (LHC), the collision rate of lead-lead beams will be increased to 50 kHz. In order to cope with this rate, the TPC was upgraded with a new amplification stage which is now based on Gas Electron Multiplier (GEM) foils. After its re-installation in the experiment, an extensive commissioning and testing program was performed.

One of the main goals of the commissioning program was the calibration of the gain. This comprises a coarse equalisation of the gas gain by fine-tuning the high voltage settings of each GEM foil stack, but also a pad-by-pad gain calibration for each electronic readout channel. In order to achieve this goal, two different types of measurements were conducted. The first one makes use of an X-ray tube which irradiated the active volume of the TPC. The second method is based on the gaseous and meta-stable radioactive isotope Kr-83m which was injected into the TPC.

In this talk, both methods will be explained in more detail. In addition to being indispensible for reaching the desired dE/dx performance of the TPC, the results of the measurements reveal interesting details on stretching issues and edge effects.

Supported by BMBF.