The fast tracker processor for hadron collider triggers

Abstract

Perspectives for precise and fast track reconstruction in future hadron collider experiments are addressed. We discuss the feasibility of a pipelined highly parallel processor dedicated to the implementation of a very fast tracking algorithm. The algorithm is based on the use of a large bank of pre-stored combinations of trajectory points, called patterns, for extremely complex tracking systems. The CMS experiment at LHC is used as a benchmark. Tracking data from the events selected by the level-1 trigger are sorted and filtered by the Fast Tracker processor at an input rate of 100 kHz. This data organization allows the level-2 trigger logic to reconstruct full resolution tracks with transverse momentum above a few GeV and search for secondary vertices within typical level-2 times.

Hadron collider triggers with high-quality tracking at very high event rates

“…W E PROPOSE the use of a dedicated hardware processor, fast-track [1] (FTK), for online pattern recognition of tracker detector data. FTK is an evolution of the Silicon Vertex Tracker (SVT) [2], the tracker now running at the Collider Detector at Fermi Lab (CDF) experiment.…”

“…It can be added even after the baseline has been built, as an upgrade, if the possibility of adding a bypass to spy on the events is included in the DAQ from the beginning. Technical details of the proposed system can be found elsewhere [1].…”

Rare decays of B mesons and baryons at the Tevatron and the LHC

“…If the detector is divided into 8 regions, each processor would receive 23 links, find clusters and organize them into the 24 inputs received by the processor core. In fact there are four inputs [89] for each one of the six FTK input buses. The dual-output HOLA board that drives both the usual DAQ data stream and an identical one to FTK was designed and tested, and passed an ATLAS board review.…”

“…If the this number of region will be considered too high, a feasible option is to operate FTK on only a subset of the Level-1 triggers. A single 9U VME crate would contain the engine core for a detector region, as described in [89]. The core size is dominated by the large bank of pre-calculated hit patterns (pattern bank) used to perform pattern recognition.…”

“…The Fast Track processor (FTK) [89] is a dedicated hardware processor for on-line pattern recognition of tracker detector data. FTK is an evolution of the SVT [90] that has been the crucial tool for reconstruction the channels discussed in this thesis.…”