Improved electronic measurement of the Boltzmann constant by Johnson noise Thermometry

Published

August 19, 2015

Author(s)

Weston L. Tew, Samuel P. Benz, Horst Rogalla, Alessio Pollarolo, David R. White, Jifeng Qu, Kunli Zhou

Abstract

The unit of thermodynamic temperature, the kelvin, will be redefined in 2018 by fixing the value of the Boltzmann constant, k. The present CODATA recommended value of k is determined predominantly by acoustic gas-thermometry results. To provide a value of k based on different physical principles, purely electronic measurements of k were performed by using a Johnson noise thermometer to compare the thermal noise power of a 200 Ω sensing resistor immersed in a triple-point-of-water cell to the noise power of a quantum-accurate pseudo-random noise waveform of nominally equal noise power. Measurements integrated over a bandwidth of 550 kHz and a total integration time of 33 days gave a measured value of k = 1.3806514(57)×10-23 J/K, for which the relative standard uncertainty is 4.1×10-6 and the relative offset from the CODATA 2010 value is +1.9×10-6.

Citation

Metrologia

Volume

52

Issue

5

Pub Type

Journals

Download Paper

https://doi.org/10.1088/0026-1394/52/5/S242

Keywords

Boltzmann Constant, Johnson Noise Thermometry, Josephson Junction, Quantized Voltage Noise Source

Citation

Tew, W. , Benz, S. , Rogalla, H. , Pollarolo, A. , White, D. , Qu, J. and Zhou, K. (2015), Improved electronic measurement of the Boltzmann constant by Johnson noise Thermometry, Metrologia, [online], https://doi.org/10.1088/0026-1394/52/5/S242 (Accessed October 20, 2025)