Low Temperature Thermal Diffusivity and Conductivity Measurements under an Identical Experimental Setup.

Abstract

A thermal diffusivity measuring system employing a closed cycle helium refrigerator was de veloped, which also enabled the thermal conductivity measurement under an identical experimen tal setup. The diffusivity was measured by a discretional heating method and the conductivity was measured by a steady-state heat flow method. The errors and the accuracy in measurements were evaluated by measuring the diffusivities of an austenitic stainless steel standard sample (SRM 1460), a Pyrex glass (Corning #7740) and a high purity copper between 12 to 200K. The diffusivity ranging from 10-3 to 2cm2/s could be determined with an uncertainty of 3%.