Skip to main content
U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Comparison of two methods for determining the sorption correction for a vacuum-realized kilogram



Patrick J. Abbott, Corey A. Stambaugh, Edward C. Mulhern, Eric C. Benck, Zeina J. Kubarych


The International System of Units (SI) is expected to be revised in 2018, and in this new system, the unit of mass, the kilogram, will be realized in a vacuum environment. In order to transfer the vacuum realization to atmospheric pressure air, the effects of the sorption of atmospheric contaminants must either be corrected for or eliminated. NIST has constructed a system that directly compares a mass in vacuum to a mass in air, thereby eliminating the need for sorption correction. We describe the operation of this system and compare results to those obtained from sorption corrections.
Proceedings Title
CPEM 2016 Conference Digest
Conference Dates
July 10-15, 2016
Conference Location
Ottawa, -1
Conference Title
CPEM 2016


revised SI, mass metrology, kilogram, vacuum, sorption correction
Created August 11, 2016, Updated November 10, 2018