Speaker
Description
The High Luminosity program of the Large Hadron Collider (HL-LHC) will improve the performance of the accelerator by increasing the instantaneous luminosity $\mathcal{L}$ up to 7.5$\cdot$ 10$^{34}$ cm$^{-2}$ s$^{-1}$, with an average of 200 proton-proton collisions per beam-crossing. An upgrade of the ATLAS detector is needed to cope with the harsher radiation levels and with a much higher number of tracks. The Inner Tracker (ITk) will be the new all-silicon tracker. The ITk innermost layer will be exposed to a fluence of 1.3$\cdot$10$^{16}$ n$_{eq}$/cm$^2$ at the half at the HL-LHC program when it is scheduled to be replaced. Considering a 1.5 safety factor the sensors placed in this layer need to be qualified up to a fluence of 2$\cdot$10$^{16}$ n$_{eq}$/cm$^2$. Due to their radiation hardness, 3D pixel sensors have been chosen to instrument the innermost layer of the detector. 3D sensors with a pixel cell 25x100 $\mu$m$^2$ have been chosen for the central region of the detector (Barrel) while the 50x50 $\mu$m$^2$ ones will instrument the two side regions (End-Caps). The latter have been characterized in laboratory and in beam tests after irradiation up to a fluence of 1.9$\cdot$10$^{16}$ n$_{eq}$/cm$^2$ during 2022. A summary of their performance before and after irradiation will be presented, with a particular focus on the pixel cell local efficiency.
