Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Milligram mass metrology using an electrostatic force balance

Published

Author(s)

Gordon A. Shaw, Julian Stirling, John A. Kramar, Alexander D. Moses, Patrick J. Abbott, Richard L. Steiner, Andrew D. Koffman, Jon R. Pratt, Zeina J. Kubarych

Abstract

Although mass is typically defined within the International System of Units (SI) at the Kilogram level, the pending redefinition of the SI provides an opportunity to realize mass at any scale using electrical metrology. We propose the use of an electromechanical balance to realize mass at the milligram level using SI electrical units. The use of a concentric-cylinder vacuum gap capacitor allows us to leverage the highly precise references available for capacitance, voltage and length to generate an electrostatic reference force. Weighing experiments performed on 1 milligram and 20 milligram artifacts show slightly lower uncertainty than similar experiments performed by subdividing the kilogram. The measurement is currently limited by the stability of the materials composing the mass artifacts and the changes in adsorbed layers on the artifact surfaces as they are transferred from vacuum to air.
Citation
Metrologia
Volume
53

Keywords

mass, force, kilogram, milligram, electrostatic force balance, metrology, SI, redefinition
Created September 28, 2016, Updated November 10, 2018