A high temperature noise thermometer for accurate thermodynamic temperature measurements

摘要

A new version of a noise thermometer was realized at the Istituto di Metrologia Gustavo Colonnetti (IMGC) to determine the thermodynamic temperature of the melting and freezing points of copper. Low-noise, low-input-capacitance amplifiers, cross-correlating amplifiers, and specially shielded resistive sensors were designed, realized, and tested. They are described and their relevant features are discussed as well as the problems associated with EMI and electrical leakages at high temperatures.