Accurate Thermal Diffusivity Instrument for Foil-like Samples with Systematic Uncertainty Quantification

Abstract

We report an accurate thermal diffusivity measurement system for relative short samples (on the order of 10 mm) in ambient conditions using a modified Ångström’s method. As compared to the original Ångström’s method, which requires the heat conduction medium to be semi-infinite, the modified Ångström’s method is applicable for short samples. In previous studies involving Ångström’s method, temperatures were typically measured in vacuum. In this work, we measured temperatures in ambient conditions, which were more convenient as compared to vacuum conditions but were also noisier. In order to quantify and reduce uncertainties from measurement noise, we developed a Bayesian framework and Metropolis algorithm for statistical analysis. We validated our instrument using a silver foil (25.0 mm × 7.0 mm × 76.5 μm ), and the measured thermal diffusivity ( 1.62 − 1.66 cm2/s) matched measurement results in previous studies (1.61 − 1.70 cm2/s).