The electronic fluctuations in voltage and current that exist in a normal conductor are a fundamental measure of thermodynamic temperature. Many challenging metrology and electronic design problems must be solved in order to fully exploit Johnson Noise as an accurate primary thermometer. Opportunities exist for experimental investigations into advanced techniques in Johnson Noise Thermometry (JNT) both as an absolute method and a relative temperature scaling technique. In the former case the data result in a determination of the Boltzmann constant, while in the latter case a thermodynamic noise temperature is compared to the current international temperature scale, the ITS-90. The established uncertainty benchmark for absolute JNT is 12 ppm at the triple point of water (273.15 K) with more recent measurements achieving statistical uncertainties of 3 ppm. New absolute JNT results impact the formulation of the new International System (SI) of Units. For temperatures in the range 505 K to 933 K, the current benchmarks for relative JNT are 26 ppm to 35 ppm. Results in this range directly impact our knowledge of the platinum reference function which is the basis for all international temperature dissemination between 13.8 K and 1234 K.

The NIST JNT research efforts are a collaboration between the Sensor Science Division in Gaithersburg, MD and the Quantum Electromagnetics Division in Boulder, CO. Possible JNT research topics for opportunities in Gaithersburg, MD include applying state of the art methods to new determinations of the Boltzmann constant, or thermodynamic realizations at high temperatures. Other possible topics include development and application of new signal processing technologies and methods. New JNT research opportunities are also available in Boulder, Co and are described under a separate posting. See postings listed for NRC advisor Benz, Samuel P.

 

key words

Digital signal processing; Electronic design; Johnson noise; Noise correlation; Noise thermometry;

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral applicants