In 2010, NIST measured the Boltzmann constant k with an electronic technique that measured the Johnson noise of a 100 Ω resistor at the triple point of water (TPW) and used a voltage waveform synthesized with a quantized voltage noise source (QVNS) as a reference. In this paper, we present measurements of k using a 200 Ω sense resistor and an appropriately modified QVNS circuit and waveform. Preliminary results show agreement with the previous value within the statistical uncertainty. Analysis is presented that identifies the largest source of uncertainty, which is the frequency dependence in the linear term of the two-parameter fit.
Citation: IEEE Transactions on Instrumentation and Measurement
Pub Type: Journals
Boltzmann equation, Josephson junction, measurement units, noise measurement, standards, temperature.