The Assembly and Testing of the Barrel Timing Layer of the HL-LHC Upgrade for the CMS Experiment

The Large Hadron Collider (LHC) is preparing to enter its High-Luminosity era, in which more densely packed proton bunches will greatly increase the collision rate. The upgrade to the collider will enable experiments to make precise measurements of Higgs boson properties and direct searches for physics beyond the Standard Model by collecting a data sample corresponding to 4,000 fb^-1 of integrated luminosity. To fully exploit this large dataset, more precise timing information is required to maintain efficiency, resolution, and background rejection. The CMS experiment will be upgraded with the MIP Timing Detector (MTD), designed to provide precision timing of charged minimum ionizing particles (MIPs). The MTD will reduce the time spread of collisions within a bunch crossing, improving the ability to associate tracks from charged particles to the correct vertices. A key component of the MTD is the Barrel Timing Layer (BTL). The BTL is made of scintillating LYSO crystals coupled to silicon photomultipliers, organized into Sensor Modules, which are packaged together into Detector Modules and deployed in trays that will tile the inner surface of the support cylinder of CMS. In this poster I will present how each of these components are assembled and discuss how quality assurance testing is performed to ensure precise detector performance at the HL-LHC.