Study on measuring Neutrino interactions with the ICARUS detector and addressing its cosmic ray background.

Abstract

The Short Baseline Neutrino (SBN) program at Fermilab is the world's most sensitive research environment where to search for sterile neutrinos at the electronvolt mass scale. The program makes use of three liquid argon time projection chambers sequentially positioned along the Booster Neutrino Beam, in this setup ICARUS serves as the far detector. The primary goal of the program is to prove or disprove anomalous results from previous experiments that imply the existence of sterile neutrinos. ICARUS was moved from its original deep underground location at LNGS in Italy to Fermilab. At Fermilab ICARUS is installed on the surface introducing a new challenge to its physics program in the form of cosmic ray contamination. To meet this challenge a Cosmic Ray Tagger (CRT) system was designed and implemented with a 4pi coverage. This thesis presents a comprehensive examination of the CRT system design, implementation, and performance, demonstrating its critical role in enabling precision neutrino physics measurements in surface environments. The thesis also presents the application of the combined ICARUS detector and CRT system capabilities for neutrino-argon cross-section measurements using the off-axis NuMI neutrino beam, focusing on the muon neutrino charged-current inclusive channel. The integration of advanced cosmic ray rejection techniques with high-resolution liquid argon imaging technology establishes important precedents for future surface-based neutrino detectors and contributes essential measurements for understanding neutrino-nucleus interactions relevant to long-baseline oscillation experiments.