ATLAS tracking at the super-LHC

Abstract

Replacement of the ATLAS tracker is necessitated by the plans to extend LHC running and to greatly increase the luminosity after a long shutdown starting in the middle of the next decade. The proposed luminosity upgrade will require replacement of the tracker to achieve the higher granularity and greatly increased radiation hardness that an order of magnitude more collisions per beam crossing will imply. Not only will this render the current straw-tube-based tracker at outer radii (the TRT) inoperable, it will also require use of even more advanced radiation hard technologies than in the current semiconductor tracker (SCT). The use of an all-silicon tracker is regarded by most as the only viable solution using new advances in substrate technology and lower temperature operation as appropriate. Additionally, the upgrade will require minimal disturbance to the rest of the experiment and be obliged to use much of the existing services infrastructure. The many challenges posed by both the extreme environment and the severe constraints coming from the very tight tracker construction timescale are discussed in this paper.