Speaker
Description
The ALICE experiment underwent significant upgrades during the LHC Long Shutdown 2 (2019–2021), including the installation of the new Inner Tracking System (ITS2). ITS2 comprises seven layers with 12.5 billion pixels spanning 10 m², based on the ALPIDE CMOS Monolithic Active Pixel Sensors (MAPS), which offer an intrinsic spatial resolution of approximately 5 µm. Designed to handle Pb-Pb collisions at interaction rates of up to 50 kHz, ITS2 delivers enhanced tracking performance, particularly in terms of impact-parameter resolution and efficiency at low transverse momentum. This improvement is achieved through its increased granularity, low material budget of 0.36% X0 per layer in the innermost layers, and the placement of the first layer at a radial distance of 23 mm from the interaction point.
ITS2 became operational at the start of LHC Run 3 and has since demonstrated excellent performance in both proton-proton and heavy-ion collisions. This contribution will present an overview of ITS2's operational experience and recent results, with a particular focus on detector calibration and tracking performance. Additionally, operational insights gained from ITS2 will be shared, highlighting lessons learned, including beam background mitigation, from which the development of future detectors like ITS3 and ALICE 3 will profit.
