Published: September 09, 2015
Michael R. Moldover, Roberto M. Gavioso, David B. Newell
We review correlated uncertainties among the accurate determinations of the Boltzmann constant kB that used the techniques of primary acoustic gas thermometry (AGT). We consider uncertainty contributions from four sources: (1) resonator-dependent uncertainties of the acoustic and microwave measurements, (2), gas-dependent uncertainties from the uncertain chemical and isotopic compositions of the test gases, (3), literature data for the gas properties, and (4), approximations in the theory of AGT. Resonator-dependent uncertainties are correlated when the same cavity was used for more than one measurement. Gas-dependent uncertainties are correlated among those measurements that used argon with isotopic abundances determined using an isotopic standard prepared at KRISS in 2006. All the AGT measurements have small correlated uncertainties from their use of literature data for the Avogadro constant, and for the thermal conductivity and the higher acoustic virial coefficients of helium or argon.
Pub Type: Journals
Boltzmann Constant, Gas Constant, Acoustic Thermometry, Fundamental Constants, Thermometry
Created September 09, 2015, Updated November 10, 2018