The Design and Development of a Tabletop Kibble Balance at NIST

Abstract

A global paradigm shift to redefine the International System of Units (SI) from a system based on seven fundamental units to seven fundamental constants is well under way. More specifically, the unit of mass, the kilogram, will be realized via a fixed value of the Planck constant $h$ and a Kibble balance (KB) serves as a method of achieving this. Over the past few decades, national metrology institutes around the world have invested in developing KBs, the majority aimed at realizing the unit of mass at the I-kg level with uncertainties on the order of a few parts in 108. However, upon fixing the Planck constant, mass can be directly realized at any level, deeming the kilogram only a historically unique benchmark. At the National Institute of Standards and Technology (NIST), a tabletop-sized Kibble balance (KIBB-gI) designed to operate at the gram-level range with uncertainties on the order of a few parts in 106 is currently under development.