Argüelles-Delgado, CarlosPrainito, Christopher2026-06-2420262026-06-242026Prainito, Christopher. 2026. Design of a Cosmic-Ray Muon-Tagged Water-Cherenkov Calibration Facility for IceCube Optical Modules. Bachelors Thesis, Harvard University Engineering and Applied Sciences.32575824https://dash.harvard.edu/handle/1/42742194The IceCube Neutrino Observatory detects astrophysical neutrinos with 5,160 optical modules frozen into South Pole ice. The recently deployed IceCube Upgrade and the planned IceCube-Gen2 extension introduce modules with richer angular acceptance and more complex timing response than the original Digital Optical Module (DOM), yet once frozen into a borehole, a module becomes permanently inaccessible. Thorough pre-deployment characterization is therefore essential. This thesis presents the design of a laboratory-scale calibration facility that uses naturally occurring cosmic-ray muons as a tagged Cherenkov source. An external three-layer scintillator telescope, composed of 3 x 3 arrays of 200 mm EJ-200 tiles with dual-ended silicon-photomultiplier (SiPM) readout, reconstructs the trajectory of each downgoing muon above a black-polypropylene water tank (approximately 2 m diameter, 0.9 m height) containing the module under test. A custom Geant4-based simulation framework, TankSim, incorporating the Cosmic-ray Shower Library (CRY) and ROOT-based analysis, guided the optimization through a 180-configuration parameter scan and high-statistics confirmation runs of 200,000 events. The key finding is that calibration accuracy is governed primarily by timing fidelity rather than by raw spatial granularity: a dedicated jitter sweep shows that reconstruction degrades rapidly above approximately 200 ps RMS of added electronics jitter, setting a concrete timing budget for the readout chain. The practical baseline achieves 145.5 mm bottom-of-tank position uncertainty (p68) and 4.56 degree angular resolution with 54 SiPM channels. A three-board readout architecture (SiPM carrier, tile controller with fast discriminators, and FPGA-based layer controller) was developed to preserve this timing information from scintillator to digital timestamp.application/pdfenCosmic-Ray MuonsIceCubeOptical Module CalibrationScintillationSilicon PhotomultipliersWater-CherenkovParticle physicsElectrical engineeringMechanical engineeringThesis or Dissertation2026-06-240000-0002-4429-7956