  The movable temperature profiler is a 7 m vertical array of 24 sensors that
measures cryogenic temperatures with a precision of a few mK. This precision is
necessary to monitor the efficiency of re-circulation and purification of
liquid-argon inside large liquid-argon based neutrino detectors. Liquid argon
temperature impacts electron (signal) drift velocity, flow, purity distribution
and thus the overall energy calibration. The temperature profiler is motorized
and moves vertically, while in the detector, and cross-calibrates neighboring
sensors. The temperature offsets between each sensor cancel the effects of
electromagnetic noise. This poster reports on the temperature measurements and
such in-situ cross-calibrations at ProtoDUNE (single phase) at CERN.
