Abstract

For the past two years, measurements have been performed with a watt balance at the National Institute of Standards and Technology (NIST) to determine the Planck constant. A detailed analysis of these measurements and their uncertainties has led to the value h = 6.626 069 79(30) x 10(-34) J s. The relative standard uncertainty is 45 x 10(-9). This result is 141 x 10(-9) fractionally higher than h(90). Here h(90) is the conventional value of the Planck constant given by h(90) = 4/((KJ-90RK)-R-2-(90)), where KJ-(90) and RK-(90) denote the conventional values of the Josephson and von Klitzing constants, respectively.

Publication Details
Publication Type
Journal Article
Year of Publication
2014
Volume
51
Number of Pages
S15-S24
DOI
10.1088/0026-1394/51/2/s15
Journal
Metrologia
Contributors
Groups