Two-Dimensional Effects on Measurement of Thermal Diffusivity by AC Calorimetric Method: III. Advantage of Double-Heating Method

Abstract

In our previous paper [F. Takahashi, Y. Hamada and I. Hatta: Jpn. J. Appl. Phys. 38 (1999) 5278], the conditions required for precise thermal diffusivity measurement along the surface of a plate-like sample using an ac calorimetric method was proposed. It was concluded that an ac calorimetric method could be applied to a relatively thick sample. In the present paper, to perform the measurement in a much thick sample, we propose a new measuring system in which ac heat flux is applied to both surfaces of the sample, and analyze the two-dimensional temperature wave propagation. Consequently, the conditions for measuring thermal diffusivity to an accuracy of ±1% are proposed.