The total hemispherical emittance measurement is based on a variation of ASTM C 835. For the specific heat measurement, the reference sample with the known specific heat and the sample to be measured are surface painted with a layer of graphite so that they have the same total hemispherical emittance dependence of the temperature. When doing test, the sample is thermally isolated from its surroundings so that all heat transfer to and from it is by radiation. The effective emittance can be determined by the testing on the reference sample. Then the specific heat of the measured sample can be obtained with the effective emittance.
Measurements is conducted under high vacuum.
This system provides an approach to measure thermal conductivity, thermal diffusivity, and specific heat of thin films. A thin NiCr metal strip is used to apply a periodic heating signal to the front surface of the thin film sample that is dielectric and deposited on a suitable substrate. The thermal properties of the substrate material must be known. A periodic temperature fluctuation is produced at the front surface and is detected by a HgCdTe infrared detector cooled to liquid nitrogen temperatures. The phase is measured between the heating signal and the temperature response.