Testing the ATLAS Phase-II MDT Trigger Processor with Cosmic-Ray Muons.

The first-level trigger of the ATLAS experiment processes up to 40 million events per second in real time using fast, dedicated hardware. It collects data from various detector components, including calorimeters and muon detectors such as Resistive Plate Chambers (RPCs) and Thin Gap Chambers (TGCs).

With the upgrade of the LHC to the High-Luminosity phase (HL-LHC), the number of simultaneous collisions (pile-up) per bunch crossing is expected to increase from around 65 to 200. To cope with these demanding conditions, the entire ATLAS detector and its trigger system will undergo a major upgrade as part of the so-called Phase-II upgrade. This term refers to the comprehensive improvements of the ATLAS detector and data acquisition system scheduled to be operational when the HL-LHC starts.

In particular, precise spatial information from the Monitored Drift Tubes (MDTs) will be incorporated into the first-level trigger to enhance muon identification and reduce the rate of misidentified muons. This is made possible through the MDT Trigger Processor (MDT-TP), which is a key component of the Level-0 muon trigger. The MDT-TP receives hit information from the MDT chambers in real time, reconstructs track segments with high precision, and forwards the results to the global trigger system. The MDT-TP relies on on-detector electronics, namely the Time-to-Digital Converters (TDCs) and Chamber Service Modules (CSMs).

Within this broader context, this project focuses on a test setup composed of three MDT chambers, along with two scintillators and the associated Phase-II on-detector electronics. The goal is to match scintillator coincidences with MDT hits and reconstruct the trajectories of cosmic ray muons using the Legendre transform, in line with the developments for the MDT-TP.