title: Thermodynamic temperature assignment to the point of inflection of the melting curve of high-temperature fixed points.
abstract: The thermodynamic temperature of the point of inflection of the melting transition of Re-C, Pt-C and Co-C eutectics has been determined to be 2747.84 ± 0.35 K, 2011.43 ± 0.18 K and 1597.39 ± 0.13 K, respectively, and the thermodynamic temperature of the freezing transition of Cu has been determined to be 1357.80 ± 0.08 K, where the ± symbol represents 95% coverage. These results are the best consensus estimates obtained from measurements made using various spectroradiometric primary thermometry techniques by nine different national metrology institutes. The good agreement between the institutes suggests that spectroradiometric thermometry techniques are sufficiently mature (at least in those institutes) to allow the direct realization of thermodynamic temperature above 1234 K (rather than the use of a temperature scale) and that metal-carbon eutectics can be used as high-temperature fixed points for thermodynamic temperature dissemination. The results directly support the developing mise en pratique for the definition of the kelvin to include direct measurement of thermodynamic temperature.
authors.affiliation: National Physical Laboratory (NPL), Hampton Road, Teddington TW11 0LW, UK emma.woolliams@npl.co.uk.
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authors.affiliation: Research Institute for Physical Measurement, National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563, Japan Division of Thermophysics and Process Measurements, National Institute of Metrology (NIM), No. 18 Bei San Huan Dong Lu, Beijing 100029, People's Republic of China.
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authors.affiliation: High Temperature Metrology Department, Laboratoire commun de métrologie (LNE-Cnam), 61 rue du Landy, Saint Denis 93210, France.
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authors.affiliation: National Physical Laboratory (NPL), Hampton Road, Teddington TW11 0LW, UK.
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authors.affiliation: Centro Español de Metrologia, C/del Alfar, 2, Tres Cantos 28760, Spain.
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authors.affiliation: Division of Thermophysics and Process Measurements, National Institute of Metrology (NIM), No. 18 Bei San Huan Dong Lu, Beijing 100029, People's Republic of China.
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authors.affiliation: All-Russian Research Institute for Optical and Physical Measurements (VNIIOFI), Ozernaya 46, Moscow 119361, Russia.
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authors.affiliation: National Physical Laboratory (NPL), Hampton Road, Teddington TW11 0LW, UK.
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authors.affiliation: Division of Thermophysics and Process Measurements, National Institute of Metrology (NIM), No. 18 Bei San Huan Dong Lu, Beijing 100029, People's Republic of China.
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authors.affiliation: National Physical Laboratory (NPL), Hampton Road, Teddington TW11 0LW, UK.
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authors.lastname: McEvoy
authors.affiliation: High Temperature Metrology Department, Laboratoire commun de métrologie (LNE-Cnam), 61 rue du Landy, Saint Denis 93210, France.
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keywords: eutectics; high-temperature fixed points; kelvin; temperature scale; thermodynamic temperature; thermometry