ATLAS Tracker Upgrade: Silicon Strip Detectors for the sLHC

It is foreseen to increase the luminosity of the Large Hadron Collider (LHC) at CERN around 2020 by about an order of magnitude to the sLHC. As the existing silicon tracking in ATLAS (pixel and strip detectors) is designed to withstand the radiation doses of the LHC only, the tracking detector (Inner Detector or ID) will need to be replaced. In order to cope with the order of magnitude increase in pile-up backgrounds at the higher luminosity, an all-silicon tracking detector is being designed. The new strip detector will use significantly shorter strips than the current Semiconductor Tracker (SCT) in order to keep the occupancy low enough. As the increased luminosity will mean a corresponding increase in radiation dose, a new generation of extremely radiation hard silicon detectors is required. A number of ATLAS R&D projects aimed at developing the sLHC layout of the ID, silicon sensors with sufficient radiation hardness, radiation-hard front-end electronics, and readout systems are ongoing to cope with the challenges of higher radiation levels and data rates. Starting from the projected layout of the ATLAS Tracker Upgrade, we will report on the achievements of the R&D projects for the upgrade and outline the available options for sufficiently radiation hard silicon sensors. Recent results from the prototype detectors under study, both before and after irradiation to sLHC fluences, will be discussed in detail. C oncepts for highly-integrated detector modules, where sensors and read-out electronics get mounted on a light-weight carbon structure with integrated services will also be shown.