A Fast hardware Tracker for the ATLAS trigger system

The trigger system at the ATLAS experiment is designed to lower the event rate occurring from the nominal bunch crossing at 40 MHz to less than 1 kHz for a designed LHC luminosity of 1034 cm−2 s−1. The LHC has successfully ran from 2010 to early 2013, routinely exceeding the design luminosity. The LHC is expected to run starting in 2015 with much higher instantaneous luminosities and this will increase the load on the High Level Trigger system. More sophisticated algorithms will be needed to achieve higher background rejection while maintaining good efficiency for interesting physics signals. The Fast TracKer upgrade project is a hardware processor that will provide full scan tracking after every level-1 accept down to a pT threshold of 1 GeV. The Fast TracKer will exploit hardware with massive parallelism combining Associative Memory ASICs, FPGAs and high speed communication links. The Fast TracKer will provide the High Level Trigger system with extensive access to tracking information