Investigation of the dew-point temperature scale maintained at the MIKES

For the investigation of the dew-point temperature scale realized by the MIKES primary dew-point generator, a two-pressure generator and a dew-point indicator based on condensation in a cooled coil were constructed and tested. In addition, a chilled mirror hygrometer was validated by means of an uncertainty analysis. The comparison of these systems was focused on the dew-point temperature range from -40°C to -20°C but measurements were made up to +75°C. The generator systems were compared using a dew-point comparator based on two relative humidity sensors. According to the results of the comparisons, the differences between the measurement systems were less than 0.05°C, while the expanded uncertainty of the MIKES generator was between ±0.05°C and ±0.08°C. The uncertainty of the other systems was from ±0.04°C to ±0.14°C. It was concluded that the dew-point temperature scale was not dependent on the realization method.