Uncertainty evaluation for linking a bilateral key comparison with the corresponding CIPM key comparison

摘要

A method for evaluating the uncertainty in linking a bilateral key comparison to another key comparison with several participants is presented theoretically and demonstrated with an actual comparison. Equations are derived for the uncertainties of the unilateral and mutual degrees of equivalence for the linked participant in the bilateral comparison. It is shown that the uncertainty components related to uncorrelated effects in the measurements of the linking participant play a critical role in determining the additional uncertainties due to the linking process. As a practical example, the results are applied to a bilateral comparison of the spectral irradiance scales of MIKES (Finland) and NIMT (Thailand) in the spectral range from 290 nm to 900 nm.