3D pixel modules characterization with RD53A readout for ATLAS ITk Upgrade

The High-Luminosity LHC (HL-LHC) with its large number of collisions per bunch crossing will present a very challenging environment to the particle detectors. To cope with these conditions, the current inner detector of the ATLAS experiment will be replaced with a new all-silicon Inner Tracker (ITk) during the Phase-II upgrade. Due to their superior radiation hardness, it has been chosen to instrument the ITk innermost layer with 3D pixel sensors. In this article the new pixel 3D sensor design and technology are reviewed, together with their characterisation before and after exposition to large radiation dose, close to the one expected for the innermost layer of ITk after 2000 fb −1 of integrated luminosity delivered by HL-LHC.