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.