Test Beam Studies of Barrel and End-Cap Modules for the ATLAS ITk Strip Detector before and after Irradiation

ATLAS is preparing for the HL-LHC, that will deliver a total integrated luminosity of up to 4000fb-1 in about ten years of operation, with a peak luminosity five times higher than that which was reached before the current LHC shutdown. To cope with the higher radiation levels and pile up, the ATLAS experiment will replace the current tracking system with an all silicon detector, the Inner Tracker (ITk), consisting of inner pixel layers and outer strip layers. The strip system will be built from modules, consisting of one n+-in-p sensor, and one or two PCB hybrids containing the front-end electronics glued directly onto the active sensor surface. Several prototypes have been tested at DESY-II and CERN SPS, built from rectangular ATLAS17LS barrel sensors and annular ATLAS12EC sensors, designed for the innermost ring (R0) of the Endcap regions. A carbon-fibre based support, with two R0 modules positioned back-to-back has been measured, as well as two separates irradiated R0s. We present results of the module performance, incl. charge collection, noise occupancy, detection efficiency, and tracking performance. The good tracking resolution allows for detailed studies of various sensor features. The results give confidence that the ITk strip detector will meet the HL-LHC requirements.