Study of the performance of the CMS Phase 2 Upgrade Silicon Outer Tracker modules

The Large Hadron Collider at CERN is entering its High-Luminosity phase (HL-LHC). To cope with the new challenges posed by increased collision rates and harsher radiation environments, the Compact Muon Solenoid (CMS) experiment will undergo a significant upgrade, including a complete redesign of its tracker. One of the main advancements in the new Outer Tracker is its ability to select particles based on a transverse momentum (pt) threshold. To achieve this, two novel silicon modules have been designed: the 2S module and the PS module, collectively referred to as pt-modules. These consist of two closely spaced silicon sensors (pixel-strip in the PS and strip-strip in the 2S) and, through dedicated front-end electronics, enable the selection of particles according to a pt threshold. This thesis presents the characterization of a PS module in its final design, identical to the version that will be deployed during data taking, with a focus on validating its performance under conditions replicating the HL-LHC environment. A dedicated test beam campaign was conducted at Fermilab in 2023, where the module's performance was evaluated before and after irradiation at fluence levels equivalent to the end-of-life conditions expected for a PS module at the conclusion of the HL-LHC phase. The analysis includes measurements of particle detection efficiency, spatial resolution, and the module's capability to select particles based on transverse momentum, which is critical for data reduction under high-luminosity conditions. The results demonstrate that the PS modules meet the required performance metrics, ensuring the CMS Outer Tracker's readiness for the HL-LHC phase and enabling precision measurements and searches for new physics beyond the Standard Model.