Dynamic Temperature Profiler in ProtoDUNE

Precise monitoring of the liquid argon temperature is crucial for large neutrino detectors such as the Deep Underground Neutrino Detector (DUNE) ploying liquid argon time projection chamber (LarTPC) technology. Liquid argon temperature impacts the ionization electron drift velocity, liquid argon flow, purity distribution and thus the overall energy calibration. The dynamic temperature profiler is a 7 m vertical array of 24 sensors which measure cryogenic temperatures with a precision of a few mK. The profiler is motorized and moves vertically, while in the detector, and cross-calibrates neighboring sensors. The high precision allows monitoring of the recirculation efficiency and purification of liquid argon while providing input to the fluid flow simulations. This talk reports on the operation of the dynamic temperature profiler in the ProtoDUNE experiment at CERN.