Measurement of Thermal Diffusivity in a Sample with a Certain Thickness by an AC-Calorimetric Distance-Variation Method: IV. Requirements for Measuring by Spot Heating

Abstract

An ac-calorimetric distance-variation method has a variety of applications in thermal diffusivity measurement of a plate like material. In this method, there are some ac heating configurations. For a periodic band heating and a periodic line heating, we have proposed the requirements for the precise measurement in our previous papers. In this paper, we analyze temperature wave propagation in a plate like sample for a periodic spot heating under the condition in which heat loss between a sample and a heat sink takes place. In such a case, the requirements for measuring thermal diffusivity by spot heating within an accuracy of AE1% are proposed. For the precise measurement, we analyze the requirements in detail for the cases using only the phase of the periodic temperature and both the phase and the amplitude, because these two methods have individual merits.