Performance of the SBND Cosmic Ray Tagger

The Short-Baseline Near Detector (SBND), a 112-ton liquid argon time projection chamber (LArTPC), is positioned just 110 meters from the Booster Neutrino Beam (BNB) target at Fermilab, making it well-suited for both neutrino interaction measurements and searches for physics beyond the Standard Model (BSM). The Cosmic Ray Tagger (CRT) is a valuable component of SBND, designed to mitigate the significant cosmic-ray background due to the detector's surface-level location. The CRT is an external tracking system consisting of overlapping plastic scintillator bars surrounding the LArTPC that will provide critical timing and spatial information for any charged particles that enter or exit the TPC volume. With SBND data collection already underway, the optimization of the CRT's time and position resolution will be instrumental in enabling efficient rejection of the cosmic ray backgrounds. The CRT provides accurate timing information which complements SBND's light collection system. Its integration in SBND analyses provides an opportunity to effectively reject cosmic-ray backgrounds with an efficient workflow. In addition, the CRT's ability to tag cosmic ray muons entering the detector provides valuable samples for commissioning and calibrating the other detector systems. This talk will present the installation and commissioning of SBND's CRT, and present the status of its current operations and performance, including an assessment of the detector optimization carried out to ensure ideal operating conditions.