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.