REDUCTION OF RADIATION ERRORS IN THERMAL-CONDUCTIVITY MEASUREMENTS ABOVE 100-K

A steady-state method for thermal conductivity measurements above 100 K on poor conductors is described. Radiation errors are made negligible using a closely fitting shield with a temperature profile matched along its length to that of the sample. Calculations show that for a typical geometry, the radiation error at room temperature is two or three orders of magnitude lower than for a shield kept at the sink temperature. The experimental setup is described and measurements on PMMA are reported. The results agree with measurements reported by other authors who use completely different methods.