An Apparatus for Measurement of Thermal Conductivity of Solids at Low Temperatures

A description is given of an apparatus used for determining the t hermal conductivities o f solids in t he temperature range 4° K to 300° K. The apparatus is especially suited to the determination of thermal conductivity over a la rge temperature interval , enabling coverage of t he temperatures between t he normal boil ing points of liquefied gases. Illustrati ve results are given for an insulator, poiytetrafiuoro ethylene, and for a high-conduct ivity commerci al coalesced copper. The thermal conductivity of the insulator increases monotonically from 0.56 milliwatt per centimeter p er degree K at 5° K , to 2.32 at 80° K. The t hermal conductiv ity of the copper has a maximum of 24.9 watts per centimeter per degr ee K at 21 ° K , and a value of 8. 15 at 5° K. The m ethods of data analys is a nd est imat ion of errors are given.