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TitleInvestigation of low-temperature fixed points by an international star intercomparison of sealed triple-point cells
Publication TypeJournal Article
Year of Publication2012
AuthorsFellmuth, B., Wolber L., Head D.I., Hermier Y., Hill K.D., Nakano T., Pavese F., Peruzzi A., Rusby R.L., Shkraba V., Steele A.G., Steur P.P.M., Szmyrka-Grzebyk A., Tew W.L., Wang L., and White D.R.
Pagination257 - 265
Date Published2012
ISSN00261394 (ISSN)
KeywordsArgon, Experimental equipments, Filling technologies, Fixed points, Gas sources, hydrogen, Intercomparisons, International Temperature Scale of 1990, Low temperatures, Measurement programs, Melting curves, Neon, Source separation, Stars, Temperature, Thermal behaviours, Triple points
AbstractAn overview of the results of an international star intercomparison of low-temperature fixed points is given. Between 1997 and 2005, 68 sealed triple-point cells (STPCs) of the twelve laboratories represented by the authors were investigated at PTB. The STPCs are used to realize the triple points of hydrogen, neon, oxygen and argon as defining fixed points of the International Temperature Scale of 1990, ITS-90. The melting curves (MCs) of all STPCs have been measured on the same experimental equipment, adhering strictly to a single measurement program. This protocol enables separation of the effects influencing the MCs and direct comparison of the thermal behaviour of the STPCs, which are quite different with respect to design, age, gas source and filling technology. In the paper, special emphasis is given to the spread of the liquidus-point temperatures and to the uncertainty of their determination. Connections between the star intercomparison and completed and ongoing international activities are also discussed. © 2012 BIPM & IOP Publishing Ltd.

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