Testing 220Rn Injection into Liquid Argon for LArTPC Detector Calibrations

Liquid Argon Time Projection Chambers (LArTPCs) are detectors used in neutrino experiments to record ionization charge and scintillation light from charged particles produced in neutrino interactions. LArTPCs enable detailed 3D reconstruction of charged particle interactions and precise measurements of quantities such as particle energy. Calibrating these detectors is critical to ensure accurate and precise measurements. Novel calibration techniques are necessary for large LArTPC detectors located deep underground, such as the Deep Underground Neutrino Experiment (DUNE), because they are exposed to a low rate of cosmic rays often used for calibrating LArTPC detectors located on the surface. 220Rn is a short-lived radioactive gas that can be injected into a LArTPC to aid in calibrations. It produces a sequence of radioactive decays in the detector that include beta decays with well-characterized ionization charge spectra and alpha decays that provide a substantial amount of scintillation light for reconstructing the decay time. This poster describes initial tests of injecting 220Rn into liquid argon in the CATS (Colorado Argon Test Stand) setup at Colorado State University; plans for scaling up the tests at the DUNE near detector "2x2" prototype at Fermilab are also presented.