Upgrade of the SND@LHC muon detectors with drift tubes

The Scattering and Neutrino Detector (SND@LHC) experiment at CERN can discriminate all neutrino flavors in a previously unexplored energy region. The signal events are interactions of neutrinos with energies between 100 GeV and 1 TeV, produced in the very forward direction from LHC pp collisions in the ATLAS interaction point. Precise muon tracking in SND@LHC is important for a correct measurement of the muon flux, crucial for both the detector operation and the estimate of background in neutrino physics analysis, and for searches of rare events with muons in the final state, such as muon trident production or the dark Higgs dimuon decay. To improve muon identification, in March 2025 two Mini Drift Tubes (MiniDT) modules, miniature versions of CMS Drift Tubes, were added to the SND@LHC muon identification system to provide additional high resolution x-y position and direction measurements. This thesis presents the integration of MiniDTs in the SND@LHC detector, DAQ and control systems, together with the developments of the offline software and results on their commissioning up to September 2025. The MiniDT installed reached a hit efficiency of approximately 97%, in agreement with the performance reported by CMS DT Detector Performance Group. In addition, the MiniDTs were also integrated into the SND@LHC offline software framework, sndsw, allowing common SND@LHC–MiniDT events to be built offline, while a preliminary tracking method based on the Hough Transform is under development to enable the standalone reconstruction of MiniDT tracks.