A New 3ω Technique for the Measurement of Thermal Conductivity and Diffusivity of Cryogenic Helium and Hydrogen and their Mixtures

Abstract We present new advances on a method known as the confined 3-omega thermal conductivity measurement technique for measuring the thermal conductivity and diffusivity of cryogenic fluids. Previous work with this device showed potential for good measurements but significant uncertainty remained in the measurement. In this work, we discuss the refinement of the physical model of the device and demonstrate the ability to measure the thermal conductivity to better than 4% accuracy for hydrogen and helium. We then use this device to measure the thermal conductivity and diffusivity of hydrogen-helium mixtures from 35-100 K and 1-40 bar.