Specific heat measurement at low temperature by thermal radiation calorimetry

Heat capacity of a disk-shaped specimen was measured in the temperature range from 150 to 310 K by means of a technique of thermal radiation calorimetry. The specimen is heated and cooled by a cylindrical heater in a vacuum chamber kept at liquid nitrogen temperature. Surfaces of the heater and the specimen were blackened with powder chemicals mixed with Bi(2)O(3) and MgO to achieve the high and constant hemispherical surface emissivity. The temperature dependence of the emissivity was derived from the spectral emissivity in the wavelength range from 3 to 200 mu m. Results of the measurements on Ni and fused quartz specimens were discussed.