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A precise instrument to determine the Planck constant, and the future kilogram

Published

Author(s)

Darine El Haddad, Frank C. Seifert, Leon S. Chao, David B. Newell, Jon R. Pratt, Carl J. Williams, Stephan Schlamminger, Shisong Li

Abstract

A precise instrument, called a watt balance, compares mechanical power measured in terms of the meter, the second and the kilogram to electrical power measured in terms of the volt and the ohm. A direct link between mechanical action and the Planck constant is established by the practical realization of the electrical units derived from the Josephson and the quantum Hall effects. We describe in this paper the fourth generation watt balance at the National Institute of Standards and Technology (NIST), and report our initial determination of the Planck constant obtained from data taken in late 2015 and beginning of 2016. A comprehensive analysis of the data and the associated uncertainties led to the SI value of the Planck constant h = 6.626 069 85(23) 10-34 J s. The relative standard uncertainty associated with this result is 34 x 10-9.
Citation
Review of Scientific Instruments

Citation

El, D. , Seifert, F. , Chao, L. , Newell, D. , Pratt, J. , Williams, C. , Schlamminger, S. and Li, S. (2016), A precise instrument to determine the Planck constant, and the future kilogram, Review of Scientific Instruments, [online], https://doi.org/10.1063/1.4953825 (Accessed October 23, 2021)
Created June 21, 2016, Updated October 8, 2019