Light Output Studies of the Barrel Timing Layer Sensors for the MIP Timing Detector

To prepare for the increase in number of particle collision interactions per bunch crossing within the high luminosity version of the Large Hadron Collider (HL-LHC), the MIP Timing Detector (MTD) will be added to the CMS detector. The Barrel Timing Layer (BTL) of the MTD will have modules of LYSO:Ce scintillating crystals read out by silicon photomultipliers (SiPMs). With ~30 ps timing resolution, these modules will allow CMS to distinguish tracks by their time of arrival. One key characteristic of the modules is the light yield (photons/MeV), which directly impacts the time resolution of the module. This talk will describe the setup and analysis used to measure the light yield and summarize results from the ongoing light output testing of the BTL prototype sensor modules.