Performance of Irradiated RD53A 3D Pixel Sensors

The ATLAS experiment at the LHC will replace its current inner tracker system for the HL-LHC era. 3D silicon pixel sensors are being considered as radiation-hard candidates for the innermost layers of the new fully silicon-based tracking detector. 3D sensors with a small pixel size of (50 x 50) mu m(2) and (25 x 100) mu m(2) compatible with the first prototype ASIC for the HL-LHC, the RD53A chip, have been studied in beam tests after uniform irradiation to 5 x 10(15) n(eq)/cm(2). An operation voltage of only 50V is needed to achieve a 97% hit efficiency after this fluence.