Photopyroelectric thermal wave setup for the absolute measurement of the thermal conductivity of low density gases

Abstract

A photopyroelectric setup for the accurate absolute measurement of the thermal conductivity of dilute gases is presented. The technique results from a modification of our previously described [Rev. Sci. Instrum. 69, 2452 (1998)] technique for the simultaneous measurement of absolute values of specific heat capacity and thermal conductivity of liquids. Measurement results are presented for different gases at room temperature and at one atmosphere as well as for the dilute Knudsen gas regime at reduced pressure. It is also demonstrated that the setup can be operated as a sensitive pressure gauge with adaptable sensitivity range.