| Article | |
| Title | Performance and operational experience of ALICE ITS2 in LHC Run 3 |
| Author(s) | Liu, J (Liverpool U.) |
| Collaboration | ALICE Collaboration |
| Publication | 2025 |
| Number of pages | 9 |
| In: | JINST 20 (2025) C07021 |
| In: | 20th Anniversary ”Trento” workshop on Advanced Silicon Radiation Detectors, Trento, It, 4 - 6 Feb 2025, pp.C07021 |
| DOI | 10.1088/1748-0221/20/07/C07021 |
| Subject category | Particle Physics - Experiment ; Nuclear Physics - Experiment ; Detectors and Experimental Techniques |
| Accelerator/Facility, Experiment | CERN LHC ; ALICE |
| Abstract | The ALICE experiment underwent major 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 covering 10 m^2, based on the ALPIDE CMOS Monolithic Active Pixel Sensors (MAPS), which offer a 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% X$_{0}$ per layer in the innermost layers, and the closer placement of the first layer at a radial distance of 22.4 mm from the interaction point.ITS2 became fully operational at the beginning of LHC Run 3 and has demonstrated excellent performance in both proton–proton and heavy-ion collisions. This paper presents a summary of the operational experience and performance of ITS2, with a particular focus on detector calibration and tracking performance. Lessons learned from ITS2 operation, including beam-induced background mitigation strategies, are also discussed in the context of guiding the development of next-generation tracking systems such as ITS3 and the ALICE 3 vertex detector. |
| Copyright/License | CC-BY-4.0 publication: © 2025-2026 The Author(s) |
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Záznam vytvorený 2025-07-19, zmenený 2025-12-09
