Heat Capacity of Copper

In order to establish the suitability of copper as a low temperature calorimetric standard, the heat capacities of four samples were measured between 1.3 and 20°K with a precision of 0.1%. All samples were at least 99.999% copper. One was a single crystal, one polycrystalline and annealed, one chill cast, and one polycrystalline and cold worked. The heat capacities of the annealed and chill cast samples differ by less than 0.1%. The heat capacity of the single crystal is 0.2% higher. The heat capacity of the cold worked sample is 0.7% higher at low temperatures and 0.3% higher above 10°K. It is concluded that high purity cast copper samples are excellent as low temperature calorimetric standards.