The Cosmic Ray Tagger system of the ICARUS detector at Fermilab

The goal of the Short Baseline Neutrino program at Fermilab is to conﬁrm, or deﬁnitely rule out, the existence of sterile neutrinos at the eV mass scale. The program searches for 𝜈 𝑒 appearance and 𝜈 𝜇 disappearance signals from the 𝜈 𝜇 → 𝜈 𝑒 oscillation in the Booster Neutrino Beamline. Neutrino interactions will be observed by two Liquid Argon Time Projection Chamber detectors at near (100 m) and far (600 m) positions from the neutrino source. The Far Detector (ICARUS T600) is a high granularity uniform self-triggering detector with 3D imaging and calorimetric capabilities allowing to reconstruct ionizing events with complex topology. ICARUS T600 is located on surface. A 4 𝜋 Cosmic Ray Tagger system was installed in order to mitigate the background induced by cosmic muons. The Cosmic Ray Tagger will identify muons crossing the detector with a resolution of few ns during the 1 ms drift time window of the Time Projection Chamber. In this paper an overview of the Cosmic Ray Tagger system, its role and performances as a tagger system are presented.