In:
Metrologia, IOP Publishing, Vol. 56, No. 4 ( 2019-08-01), p. 045006-
Abstract:
We report speed of sound measurements in helium at 273.16 K and at eight temperatures in the range between 236 K and 430 K. These results determine the difference ( T − T 90 ) between the thermodynamic temperature T and its approximation T 90 by the International Temperature Scale of 1990 (ITS-90). The uncertainty of our measurements of ( T − T 90 ) spans between a minimum of 0.25 mK near 247 K and a maximum of 0.89 mK at the freezing point of indium (429.75 K) with comparable contributions from the uncertainty of our acoustic determination of T and from the uncertainty of our laboratory realization of ITS-90. On the overlapping temperature ranges these results are consistent with other recent acoustic determinations of ( T − T 90 ). We also present evidence that ( T − T 90 ) can be determined with comparably small uncertainties by the alternative, time-saving procedure of measuring the speed-of-sound in helium using only a single, judiciously-chosen, pressure on each isotherm.
Type of Medium:
Online Resource
ISSN:
0026-1394
,
1681-7575
DOI:
10.1088/1681-7575/ab29a2
Language:
Unknown
Publisher:
IOP Publishing
Publication Date:
2019
detail.hit.zdb_id:
1460891-1
SSG:
11
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