Speaker
Description
The MIP Timing Detector (MTD) is a new subsystem being developed for the Phase-2 upgrade of the Compact Muon Solenoid (CMS) experiment at the CERN LHC. It is designed to measure the time of arrival of charged particles with a precision of 30–60 ps. This precise timing information will significantly mitigate the effects of the high pileup expected at the High-Luminosity LHC (HL-LHC), thereby enhancing the overall event reconstruction capabilities of CMS. The central region of the MTD, known as the Barrel Timing Layer (BTL), employs LYSO:Ce scintillating crystal bars coupled to silicon photomultipliers (SiPMs). In this talk, we present an overview of the BTL design and report on the latest results from the 2025 CERN test beam campaign, which used final module prototypes read out with the final-design front-end electronics. We will also discuss the performance of modules with variations in light yield, gluing quality and energy resolution, and provide new insights into the expected operation of the detector under realistic experimental conditions.