ALICE Inner Tracking System: from ITS2 design, construction, and performance to ITS3 advancements

by Jian Liu (University of Liverpool (GB))

Wednesday 21 May 2025, 13:30 → 14:30 Europe/London

Small Lecture Theatre (Poynting)

The new Inner Tracking System (ITS2) of the ALICE experiment at the LHC, installed during Long Shutdown 2 (2019–2021), utilizes ALPIDE CMOS Monolithic Active Pixel Sensors (MAPS). Currently operational in LHC Run 3, ITS2 demonstrates excellent tracking performance, marking the largest-scale implementation of MAPS technology in high-energy physics and its first-ever deployment at the LHC.

 

The forthcoming ITS3 upgrade, scheduled for installation during Long Shutdown 3 (2026–2029), will replace the three innermost layers of ITS2 to further enhance tracking precision and efficiency. ITS3 will feature wafer-scale stitched MAPS fabricated using 65 nm CMOS technology, thinned to 50 µm, and bent into truly cylindrical layers cooled by air, significantly reducing the detector’s material budget.

 

This seminar will provide an overview of the ITS2 detector design, construction, commissioning, operational experience, and key lessons learned, which directly inform the development of next-generation detectors such as ITS3 and ALICE 3. Recent achievements in ITS3 design, sensor characterisation, mechanical integration, and progress towards the final MOSAIX prototype will also be presented.