A quantum-voltage-calibrated Johnson-noise thermometer was developed at NIM, which measures the Boltzmann constant k through comparing the thermal noise across a 100 sense resistor at the temperature of the triple point water to the comb-like voltage waveform synthesized with a bipolar-pulse-driven quantum-voltage-noise source. A measurement with integration period of 10 hours and bandwidth of 640 kHz results in a relative offset of 0.5x10^-6 from the current CODATA value of k, and a type A relative standard uncertainty of 23x10^-6. Benefiting from closely matched noise power and transmission line impedances, small nonlinearities in the cross-correlation electronics, and some other possible reasons, the derived k shows self-consistent values and standard uncertainties for different measurement bandwidths.
Proceedings Title: Temperature: Its Measurement and Control in Science and Industry, Vol. 8
Conference Dates: March 19-23, 2012
Conference Location: Anaheim, CA
Conference Title: 9th International Temperature Symposium (ITS9)
Pub Type: Conferences
Boltzmann constant, Correlation, Josephson junction arrays, Noise, Quantization, Thermometry