Study of MAPS silicon detector prototypes for ALICE ITS3 upgrade.

The ALICE experiment at CERN has planned an upgrade of the Inner Tracking System (ITS), named ITS3, for the LHC Long Shutdown 3, in 2025. The cornerstone of the upgrade is a new CMOS pixel sensor built in $65 {nm}$ technology and in bent-cylindrical configuration, replacing the inner layers of the existing detector. The ITS3 will reach unprecedented tracking and vertexing performance, thanks to the improved spatial resolution and the much-reduced material budget. Results of data collected at beam tests using both bent ALPIDE chips and APTS Source Follower, a flat analog pixel sensor prototype, will be reported. The performance in terms of their total efficiency and spatial resolution in different experimental configurations will be discussed.