FPGA-based fast track reconstruction for the conceptual design of STCF MDC trigger

Abstract

The Super Tau-Charm Facility (STCF) is a future high luminosity electron-positron collider proposed in China, with a peak luminosity greater than 0.5× 1035 cm2s-1 at center-of-mass energy of 4.0 GeV. The main drift chamber (MDC) is designed as the central tracker, which provides the charged particle information for the level-1 trigger. This paper presents an FPGA-based fast trigger algorithm with the function of finding the charged particle tracks and reconstructing their transverse momentum and azimuthal angle. It adopts a two-stage lookup-table-based pattern matching architecture. The prototype trigger logic was implemented in a Xilinx XCKU060 FPGA. Test results with simulated data suggest that the trigger efficiency of J/Ψ events is better than 96%, and the resolution in the reconstructed track's azimuthal angle at the interaction point is better than 12 mrad. The overall dead time is 24 ns and the total latency is 339 ns. All these performances meet the requirements of the MDC trigger in the current conceptual design stage of STCF project.