Erlangen 2026 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 17: Instrumentation III

HK 17.3: Talk

Tuesday, March 17, 2026, 17:00–17:15, PHIL A 301

Drift-field distortion corrections of the ALICE TPC in LHC Run 3 — •Janis Jäger for the ALICE Germany collaboration — Institut für Kernphysik, Goethe-Universität Frankfurt

At CERN’s Large Hadron Collider (LHC), the Time Projection Chamber (TPC) of the ALICE experiment provides an excellent tracking and particle identification performance. For LHC Run 3, the Multiwire Proportional Chambers (MWPCs) were replaced with stacks of four Gas Electron Multiplier (GEM) foils to cope with the high interaction rates of up to 50 kHz and enabling a continuous data acquisition. Despite the low intrinsic ion-backflow properties of the 4-GEM setup, a residual amount of ions, produced during the amplification process, drift back into the active volume of the TPC, leading to space-charge distortions of the drift field. Further effects such as geometric imperfections and interaction rate variations lead to additional static and time-dependent drift-field distortions. These drift-field distortions need to be corrected to preserve the intrinsic particle tracking precision of the ALICE TPC.

This talk will give an overview of the observed drift-field distortions in the ALICE TPC in Run 3, together with the correction procedure and its precision.

Supported by BMFTR and the Helmholtz Association.

Keywords: ALICE; TPC; Drift-field distortions