Development of FTK architecture: a fast hardware track trigger for the ATLAS detector

TL;DR

The FTK architecture is a high-speed hardware track trigger system for the ATLAS detector, capable of reconstructing high-quality tracks in approximately one millisecond using massively parallel associative memories and FPGA technology.

Contribution

This paper presents the design and simulation of a novel FTK architecture that achieves real-time track reconstruction at Level-1 trigger rates using advanced parallel processing techniques.

Findings

FTK can process all tracks in an event within about one millisecond.

The system maintains high reconstruction quality comparable to offline algorithms.

FTK operates continuously at Level-1 rates without deadtime.

Abstract

The Fast Tracker (FTK) is a proposed upgrade to the ATLAS trigger system that will operate at full Level-1 output rates and provide high quality tracks reconstructed over the entire detector by the start of processing in Level-2. FTK solves the combinatorial challenge inherent to tracking by exploiting the massive parallelism of Associative Memories (AM) that can compare inner detector hits to millions of pre-calculated patterns simultaneously. The tracking problem within matched patterns is further simplified by using pre-computed linearized fitting constants and leveraging fast DSP's in modern commercial FPGA's. Overall, FTK is able to compute the helix parameters for all tracks in an event and apply quality cuts in approximately one millisecond. By employing a pipelined architecture, FTK is able to continuously operate at Level-1 rates without deadtime. The system design is defined and studied using ATLAS full simulation. Reconstruction quality is evaluated for single muon events with zero pileup, as well as WH events at the LHC design luminosity. FTK results are compared with the tracking capability of an offline algorithm.