TUNNELING THERMOMETER

A design is presented for a tunneling thermometer that will not require calibration to temperature standards (ITS-90), but can be directly calibrated with respect to more convenient and accurate mechanical and time standards (kg, m, Hz). The proposed thermometer converts the energy of thermal oscillations of a cantilevered quartz beam of submillimeter size into an electrical signal through tunneling-current modulation. The tunneling sensor can operate in the temperature range 200-1300 K with a calibration accuracy of 10(-4)-10(-6) and has a lifetime stability of 10(-6)-10(-7) after initial calibration. This thermometer is simply constructed (sensor head, electronic module and computer interface) and can be built as a portable or remote-operated unit. It can be applied as a virtually drift-free portable temperature reference.