Steady State Heat Transfer Characteristics in He I and He II with a Copper Surface
Steady-state heat transfer in He I and saturated He II has been measured. The bath temperatures are 4.20 K, 1.90 K and 1.78 K in saturated pressure. The sample is an oxygen free copper cylinder 20mm in diameter. It is mounted in a vacuum chamber for thermal insulation with an exposed surface facing upward into the He coolant. The heat transfer surface is polished by 0.5 μm alumina powder or oxidized by the chemicals. A thermofoil heater is attached on the opposite side of the heat transfer surface. The surface temperature is estimated by a temperature gradient in the cylinder. The temperatures are measured by calibrated germanium resistance temperature sensors. Dependence of the heat transfer characteristics from the copper surfaces to He I and He II on the surface treatment are discussed.
KeywordsHelium Epoxy Boiling Germanium Flange
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