The ATLAS ITk Detector System for the Phase-II LHC Upgrade

The ATLAS experiment is planning a complete replacement of its inner detector with a new all-silicon inner tracker for the high luminosity phase of the LHC. The new detector is designed to cope with the increased pile up, data rates and radiation levels of the HL-LHC, while maintaining or improving the current ATLAS tracking performance. The ITk design and technology R&D have been completed and pre-production of the detector modules is starting. This paper presents the ITk layout, performance and the ongoing transition into production phase.