The ALICE Pixel Readout Upgrade

The ALICE experiment at CERN is developing an upgrade of the three innermost layers of the Inner Tracking System (ITS3) to be installed during the Long Shutdown 3 of the LHC (2026–28). Based on a commercial 65 nm CMOS imaging technology for monolithic active pixel sensors, it consists of truly cylindrical wafer-scale bent stitched detectors that can be installed as close as 18 mm to the interaction point and will dramatically reduce the material budget in the region close to the interaction point to 0.05% X0 per layer. This contribution provides an overview on the development of sensor readout for prototypes based on the 65 nm technology within the context of the ITS3 upgrade R&D;, as well as an outlook on the final readout system, including requirements, plans, and current advancements.