Effect of the response delay of the measuring system on thermal diffusivity measurement using the flash method

This work investigates the effect of the response delay of a measuring syst em on a thermal diffusivity measurement. A model of an m th-order delay in the measuring system is introduced, and a general expression for the output of the system with temperature response as input is derived. The effect on the temperature response caused by such a system is discussed. As a practi cal example, a third-order measuring system is considered. The measured tem perature responses of stainless steel foils are compared with those calcula ted with the model of a third-order delay system. Good agreement between th e two results is shown.