title: Invited Article: A precise instrument to determine the Planck constant, and the future kilogram.
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 the 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 83(22) × 10(-34) J s. The relative standard uncertainty associated with this result is 34 × 10(-9).
authors.affiliation: National Institute of Standards and Technology (NIST), 100 Bureau Drive Stop 8171, Gaithersburg, Maryland 20899, USA.
authors.forename: D
authors.initials: D
authors.lastname: Haddad
authors.affiliation: National Institute of Standards and Technology (NIST), 100 Bureau Drive Stop 8171, Gaithersburg, Maryland 20899, USA.
authors.forename: F
authors.initials: F
authors.lastname: Seifert
authors.affiliation: National Institute of Standards and Technology (NIST), 100 Bureau Drive Stop 8171, Gaithersburg, Maryland 20899, USA.
authors.forename: L S
authors.initials: LS
authors.lastname: Chao
authors.affiliation: National Institute of Standards and Technology (NIST), 100 Bureau Drive Stop 8171, Gaithersburg, Maryland 20899, USA.
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.affiliation: National Institute of Standards and Technology (NIST), 100 Bureau Drive Stop 8171, Gaithersburg, Maryland 20899, USA.
authors.forename: D B
authors.initials: DB
authors.lastname: Newell
authors.affiliation: National Institute of Standards and Technology (NIST), 100 Bureau Drive Stop 8171, Gaithersburg, Maryland 20899, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Pratt
authors.affiliation: National Institute of Standards and Technology (NIST), 100 Bureau Drive Stop 8171, Gaithersburg, Maryland 20899, USA.
authors.forename: C
authors.initials: C
authors.lastname: Williams
authors.affiliation: National Institute of Standards and Technology (NIST), 100 Bureau Drive Stop 8171, Gaithersburg, Maryland 20899, USA.
authors.forename: S
authors.initials: S
authors.lastname: Schlamminger