Star intercomparison of sealed triple-point cells filled with cryogenic gases



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L. Wolber, B. Fellmuth

Star intercomparison of sealed triple-point cells filled with cryogenic gases

ISBN: 978-3-95606-046-5   |   Erscheinungsjahr: 2013    |    Auflage: 1
Seitenzahl: 30   |    Einband: Broschur    |    Gewicht: 116 g
Lieferzeit: 2-3 Tage
9,50 €
Inkl. 7% MwSt., zzgl. Versandkosten bei Auslandsbestellungen

The realisation of the triple points of the cryogenic gases hydrogen, neon, oxygen and argon as temperature fixed points at the highest level of accuracy requires the consideration of special properties of these fixed-point substances. In particular, their very small thermal conductivity caues problems in measuring the temperature of the solid-liquid interface, which represents the true fixed-point temperature. Thus, a detailed measurement protocol has been developed. The protocol contains recommendations in different directions: determination of the thermal parameters of the sealed cells containing the fixed-point substance and of the apparatus, measurement conditions, series of measurements, reporting of data, establishment of an uncertainty budget, especially the reliable estimation of static and dynamic temperature-measurement errors. The protocol was first applied in a star intercomparison of sealed fixed-point cells perfomed at PTB, and with slight improvements also in the framework of a European project. Considering the newest developments, the state-of-the-art level of the realisation of the low-temperature fixed points is considered in this report.

PTB Th-4