Milligram mass metrology using an electrostatic force balance

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

Research output: Contribution to journalArticlepeer-review

57 Citations (SciVal)
200 Downloads (Pure)


Although mass is typically defined within the International System of Units (SI) at the kilogram level, the pending SI redefinition 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. An integrated 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 mg and 20 mg artifacts show the same or lower uncertainty than similar experiments performed by subdividing the kilogram. The measurement is currently limited by the stability of the materials that compose the mass artifacts and the changes in adsorbed layers on the artifact surfaces as they are transferred from vacuum to air.
Original languageEnglish
Pages (from-to)A86-A94
Number of pages9
Issue number5
Publication statusPublished - 28 Sept 2016


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