Comparisons of some NIST fixed-point cells with similar cells of other standards laboratories

摘要

In this paper we present results of international comparisons of fixed-point cells of some of the defining fixed-point materials of the International Temperature Scale of 1990. These comparisons involved cells from seven national laboratories, although in some cases only one type of fixed-point material was compared. Except for silver cells, the agreement among cells of the same defining fixed-point material from the various laboratories was to within 1 mK. The expanded uncertainties (k=2) of the comparison measurements were 12 μK for Ga, 18 μK for H_(2)O, 27 μK for Sn, 35 μK for In, 37 μK for Zn, 42 μK for Al, and 55 μK for Ag.