ATLAS ITk Pixel Pre-production Planar Sensor Characterisation for the HL-LHC Upgrade

In the ATLAS detector upgrade for the High-Luminosity LHC (HL-LHC), the current Inner Detector will be replaced with an all-silicon Inner Tracker (ITk), to operate under higher occupancy (instantaneous luminosity $7.5\times10^{34}\;\rm cm^{-2}s^{-1}$, which corresponds to about 200 inelastic pp collisions per bunch crossing) and radiation damage (particle fluence up to $2\times10^{16}\;\rm n_{eq}/cm^2$). The data taking is planned to start in 2029 and last for 10\,years. The innermost part of the ITk will be equipped with pixel modules, consisting of pixel sensors and novel ASICs, implemented in 65\,nm CMOS technology. The ITk project is currently in pre-production stage. To assure that specifications will be met during production, sensors and test structures from different vendors were sent to different sites for irradiation, hybridisation and follow-up testing. This paper presents the results of the characterisation of the pre-production planar sensor for ITk.