Scintillating tile and silicon photomultiplier characterization for the LFHCal of the ePIC experiment

Characterization of the performance of the 565,760 plastic scintillating tiles which will comprise the ePIC Longitudinal Forward Hadronic Calorimeter (LFHCal) is critical for the science mission of the experiment, allowing for precise measurements of the fragmentation products of the proton or heavy ion. Uniformity of response of machined and injection-molded tiles (which have different tolerances in size, thickness, and dimple size as well as different light yields) to incident radiation from radioactive sources and cosmic rays is tested. In a novel design, tiles are placed directly on silicon photomultipliers (SiPMs) attached to printed circuit boards. Optimal operating parameters of the SiPMs, such as the bias voltage and ADC threshold are found. Tiles with various defects are also studied to determine the effect of imperfections due to the manufacturing, transportation, storage, installation, and data-taking processes. Yale University is preparing to play a leading role in testing of these tiles and SiPMs. In this talk, we present these studies and plans for future tile characterization.