Mirage-effect measurement of thermal diffusivity. Part II: theory

Abstract

A three-dimensional theory of a mirage-effect technique for measuring thermal diffusivity of solids is presented. A formula that incorporates sizes and separations of the heating and probe beams; the height of the probe beam above the sample surface; the thermal properties of the sample, the gas, and the backing; and the thickness of the sample is developed. The results are compared with experiments on a bulk sample and on thin slabs of various thicknesses.