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G Machin - One of the best experts on this subject based on the ideXlab platform.
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estimates of the difference between Thermodynamic Temperature and the international Temperature scale of 1990 in the range 118 k to 303 k
Philosophical Transactions of the Royal Society A, 2016Co-Authors: R Underwood, G Sutton, M De Podesta, L Stanger, R L Rusby, P M Harris, Paul Morantz, G MachinAbstract:Using exceptionally accurate measurements of the speed of sound in argon, we have made estimates of the difference between Thermodynamic Temperature, T , and the Temperature estimated using the International Temperature Scale of 1990, T 90 , in the range 118 K to 303 K. Thermodynamic Temperature was estimated using the technique of relative primary acoustic thermometry in the NPL-Cranfield combined microwave and acoustic resonator. Our values of ( T − T 90 ) agree well with most recent estimates, but because we have taken data at closely spaced Temperature intervals, the data reveal previously unseen detail. Most strikingly, we see undulations in ( T − T 90 ) below 273.16 K, and the discontinuity in the slope of ( T − T 90 ) at 273.16 K appears to have the opposite sign to that previously reported.
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evaluation and selection of high Temperature fixed point cells for Thermodynamic Temperature assignment
International Journal of Thermophysics, 2015Co-Authors: Yoshiro Yamada, K Anhalt, P Bloembergen, M. Battuello, B. B. Khlevnoy, G Machin, M Matveyev, M Sadli, A D W Todd, T. WangAbstract:A multi-partner project to determine the Thermodynamic Temperatures of a selected set of high-Temperature fixed points based on metal-carbon eutectics is underway as a working group activity within the Comite International des Poids et Mesures. The investigation focuses on four fixed-point types, namely, the three metal-carbon eutectic points of Re-C \((2474\,^{\circ }\hbox {C})\), Pt-C \((1738\,^{\circ }\hbox {C})\), and Co-C \((1324\,^{\circ }\hbox {C})\), and the Cu point \((1084.62\,^{\circ }\hbox {C})\). This paper describes the construction, pre-evaluation, and screening stage of the cells prior to their Thermodynamic Temperature determinations. The construction of the HTFP cells was undertaken by nine national metrology institutes (NMIs) according to instructions laid out in a pre-agreed protocol that ensures production of best quality cells. Four NMIs conducted the evaluation, each for a certain fixed-point type, and screened out cells that did not meet pre-determined selection criteria while assuring sufficient variety in the sources of the cells in the final selected sets. In autumn 2012, the selected cells were successfully passed on to the final stage of the project, the Thermodynamic Temperature measurement, and assignment.
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progress report for the cct wg5 high Temperature fixed point research plan
TEMPERATURE: ITS MEASUREMENT AND CONTROL IN SCIENCE AND INDUSTRY VOLUME 8: Proceedings of the Ninth International Temperature Symposium, 2013Co-Authors: G Machin, K Anhalt, P Bloembergen, Yoshiro Yamada, M Sadli, Emma R WoolliamsAbstract:An overview of the progress in High Temperature Fixed Point (HTFP) research conducted under the auspices of the CCT-WG5 research plan is reported. In brief highlights are: Provisional long term stability of HTFPs has been demonstrated. Optimum construction methods for HTFPs have been established and high quality HTFPs of Co-C, Pt-C and Re-C have been constructed for Thermodynamic Temperature assignment. The major sources of uncertainty in the assignment of Thermodynamic Temperature have been identified and quantified. The status of absolute radiometric Temperature measurement has been quantified through the circulation of a set of HTFPs. The measurement campaign to assign low uncertainty Thermodynamic Temperatures to a selected set of HTFPs will begin in mid-2012. It is envisaged that this will be complete by 2015 leading to HTFPs becoming routine reference standards for radiometry and high Temperature metrology.
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a comparison of the its 90 among npl nim and cem above the silver point using high Temperature fixed points
International Journal of Thermophysics, 2010Co-Authors: G Machin, W Dong, M. J. Martín, Z. Yuan, D Lowe, Tao Wang, X. LuAbstract:A prototype comparison of the ITS-90, as realized by NPL, NIM, and CEM, using high-Temperature fixed points (HTFPs) of Co-C (1324 °C), Pt-C (1738 °C), and Re-C (2474 °C), is reported. The local realizations of ITS-90 Temperatures were assigned by NPL, NIM, and CEM to their own set of HTFPs. NIM and CEM then transported their cells to NPL, and the ITS-90 Temperatures of all three sets of cells were measured using a linear pyrometer. From these measurements, a comparison reference value (CRV) was derived. At the Co-C and Pt-C points, the deviation from the CRV was <0.1 °C for all three institutes; at the Re-C point, the deviation was <0.4 °C. These deviations are significantly less than the scale realization uncertainties ascribed by the individual institutes indicating that these uncertainty estimates are conservative and could be revised to smaller values. In addition, Thermodynamic Temperatures were determined for these HTFPs using the current value of the Thermodynamic Temperature for the copper point, namely, 1357.82 K. Given the consistent performance of the HTFPs, they should be seriously considered as scale comparison artifacts of choice when comparing primary realizations of the ITS-90 and of the Thermodynamic Temperature.
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Thermodynamic Temperature determinations of co c pd c pt c and ru c eutectic fixed point cells
Metrologia, 2006Co-Authors: Klaus Anhalt, G Machin, M Sadli, J T Hartmann, D Lowe, Yoshiro YamadaAbstract:Thermodynamic Temperatures during the melt and the freeze of Co?C, Pd?C, Pt?C and Ru?C metal?carbon fixed-point cells manufactured by LNE?INM/CNAM, NMIJ and NPL were determined by absolutely calibrated filter radiometers traceable to the PTB cryogenic radiometer and a radiance comparison method using an IKE LP3 radiation thermometer. The measurement uncertainties were below 400?mK at Temperatures up to 2250?K. The results are in agreement within the combined uncertainties with a study on relative Temperature differences of the same set of fixed-point cells. For the fixed-point cells manufactured by NPL the results are compared with a previous Thermodynamic Temperature measurement.
Klaus Anhalt - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic Temperature assignment to the point of inflection of the melting curve of high Temperature fixed points
Philosophical Transactions of the Royal Society A, 2016Co-Authors: Emma R Woolliams, S. Briaudeau, Mark Ballico, F Bourson, D Del Campo, Klaus Anhalt, P Bloembergen, J Campos, W Dong, M R DuryAbstract: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.
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Thermodynamic Temperature by primary radiometry
Philosophical Transactions of the Royal Society A, 2016Co-Authors: Klaus Anhalt, Graham MachinAbstract:Above the freezing Temperature of silver (1234.93 K), the International Temperature Scale of 1990 (ITS-90) gives a Temperature, T 90 , in terms of a defining fixed-point blackbody and Planck9s law of thermal radiation in ratio form. Alternatively, by using Planck9s law directly, Thermodynamic Temperature can be determined by applying radiation detectors calibrated in absolute terms for their spectral responsivity. With the advent of high-quality semiconductor photodiodes and the development of high-accuracy cryogenic radiometers during the last two decades radiometric detector standards with very small uncertainties in the range of 0.01–0.02% have been developed for direct, absolute radiation thermometry with uncertainties comparable to those for the realization of the ITS-90. This article gives an overview of a number of design variants of different types of radiometer used for primary radiometry and describes their calibration. Furthermore, details and requirements regarding the experimental procedure for obtaining low uncertainty Thermodynamic Temperatures with these radiometers are presented, noting that such radiometers can also be used at Temperatures well below the silver point. Finally, typical results obtained by these methods are reviewed.
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Thermodynamic Temperature determinations of co c pd c pt c and ru c eutectic fixed point cells
Metrologia, 2006Co-Authors: Klaus Anhalt, G Machin, M Sadli, J T Hartmann, D Lowe, Yoshiro YamadaAbstract:Thermodynamic Temperatures during the melt and the freeze of Co?C, Pd?C, Pt?C and Ru?C metal?carbon fixed-point cells manufactured by LNE?INM/CNAM, NMIJ and NPL were determined by absolutely calibrated filter radiometers traceable to the PTB cryogenic radiometer and a radiance comparison method using an IKE LP3 radiation thermometer. The measurement uncertainties were below 400?mK at Temperatures up to 2250?K. The results are in agreement within the combined uncertainties with a study on relative Temperature differences of the same set of fixed-point cells. For the fixed-point cells manufactured by NPL the results are compared with a previous Thermodynamic Temperature measurement.
Graham Machin - One of the best experts on this subject based on the ideXlab platform.
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dissemination of Thermodynamic Temperature above the freezing point of silver
Philosophical Transactions of the Royal Society A, 2016Co-Authors: Mohamed Sadli, S. Briaudeau, Graham Machin, K Anhalt, F Bourson, D Del Campo, A Diril, O Kozlova, D Lowe, J Mantilla M AmorAbstract:The mise-en-pratique for the definition of the kelvin at high Temperatures will formally allow dissemination of Thermodynamic Temperature either directly or mediated through high-Temperature fixed ...
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Thermodynamic Temperature by primary radiometry
Philosophical Transactions of the Royal Society A, 2016Co-Authors: Klaus Anhalt, Graham MachinAbstract:Above the freezing Temperature of silver (1234.93 K), the International Temperature Scale of 1990 (ITS-90) gives a Temperature, T 90 , in terms of a defining fixed-point blackbody and Planck9s law of thermal radiation in ratio form. Alternatively, by using Planck9s law directly, Thermodynamic Temperature can be determined by applying radiation detectors calibrated in absolute terms for their spectral responsivity. With the advent of high-quality semiconductor photodiodes and the development of high-accuracy cryogenic radiometers during the last two decades radiometric detector standards with very small uncertainties in the range of 0.01–0.02% have been developed for direct, absolute radiation thermometry with uncertainties comparable to those for the realization of the ITS-90. This article gives an overview of a number of design variants of different types of radiometer used for primary radiometry and describes their calibration. Furthermore, details and requirements regarding the experimental procedure for obtaining low uncertainty Thermodynamic Temperatures with these radiometers are presented, noting that such radiometers can also be used at Temperatures well below the silver point. Finally, typical results obtained by these methods are reviewed.
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Erratum to: Experimental assessment of Thermodynamic Temperature dissemination methods at the highest Temperatures
17th International Congress of Metrology, 2015Co-Authors: Mohamed Sadli, S. Briaudeau, Graham Machin, K Anhalt, F Bourson, D Del Campo, A Diril, O Kozlova, D Lowe, J Mantilla M AmorAbstract:Due to problems that have occurred during the conversion of the article into PDF format, and the resulting loss of many special characters, a new correct version of the article is published below. In the frame of the European Metrology Research Programme (EMRP)-funded joint research project “Implementing the new kelvin” one work package is devoted to the assessment of two different methods of dissemination of the Thermodynamic Temperature. These two methods are the dissemination via high Temperature fixed points (HTFP) with assigned Thermodynamic Temperatures and the dissemination by radiometers or radiation thermometers calibrated in terms of Thermodynamic Temperature. To achieve a thorough assessment of these two distinct dissemination methods two dissemination exercises were organised in the form of comparisons. In one case the circulating artefacts were off-the-shelf high-Temperature fixed point cells with transition Temperatures ranging from 1324 °C to 2474 °C, in the other case absolutely calibrated pyrometers and filter radiometers were compared in the Temperature range 1000 °C to 2500 °C. This work showed that both schemes offered suitable routes for dissemination with competing advantages and drawbacks and would most probably help disseminating Thermodynamic Temperature in the future at the level of 1 K to 2 K uncertainty over the whole Temperature range.
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Experimental assessment of methods of dissemination of the Thermodynamic Temperature at the highest Temperatures
17th International Congress of Metrology, 2015Co-Authors: Mohamed Sadli, S. Briaudeau, Graham Machin, K Anhalt, F Bourson, D Del Campo, A Diril, D Lowe, J Mantilla M Amor, M. J. MartínAbstract:In the frame of the European Metrology Research Programme (EMRP)-funded joint research project “Implementing the new kelvin” one work package is devoted to the assessment of two different methods of dissemination of the Thermodynamic Temperature. These two methods are the dissemination via high Temperature fixed points (HTFP) with assigned Thermodynamic Temperatures and the dissemination by radiometers or radiation thermometers calibrated in terms of Thermodynamic Temperature. To achieve a thorough assessment of these two distinct dissemination methods two dissemination exercises were organised in the form of comparisons. In one case the circulating artefacts were off-the-shelf high-Temperature fixed point cells with transition Temperatures ranging from 1324 °C to 2474 °C, in the other case absolutely calibrated pyrometers and filter radiometers were compared in the Temperature range 1000 °C to 2500 °C. This work showed that both schemes were achievable with competing advantages and drawbacks and would most probably help disseminating Thermodynamic Temperature in the future at the level of 1 K to 2 K uncertainty over the whole Temperature range.
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Construction of high-Temperature fixed-point cells for Thermodynamic Temperature assignment
2013Co-Authors: Yoshiro Yamada, Mohamed Sadli, Graham Machin, K Anhalt, P Bloembergen, M. Battuello, M Matveyev, B. Khlevnoy, T. WangAbstract:A multi-partner project is currently being conducted within Working Group 5 (Radiation thermometry) of the CIPM Consultative Committee for Thermometry (CCT), which aims at assigning Thermodynamic Temperatures to a selected set of high-Temperature fixed-points (HTFPs) based on metal-carbon eutectics. A work package of this project (WP2) consists in producing sets of HTFP cells to serve the final phase of the project, assignment of definitive Thermodynamic Temperatures (WP5). The four fixed-point types are the metal-carbon eutectic points, Re-C (2474 °C), Pt-C (1739 °C), and Co-C (1324 °C), and the Cu point (1084.62 °C). The first phase of the WP2 work treats the construction of HTFP cells, which were carried out by eight National Metrology Institutes (NMIs). The cells were constructed in accordance to instructions laid out in the WP protocol, based on years of experience of WG5 member NMIs. Cells constructed in this way should, in principle, have the required performance in terms of the realized Temperature, reproducibility, and long term stability. The constructed cells were then evaluated for their performance in the second phase of the WP. The WP aims at identifying at least four cells of each of the four fixed-point types to be supplied to WP5 of the CCT-WG5 research plan for final Thermodynamic Temperature assignment. This paper describes the first phase of the WP2. Details of the cell construction conditions and procedures are presented.
R Underwood - One of the best experts on this subject based on the ideXlab platform.
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progress towards the determination of Thermodynamic Temperature with ultra low uncertainty
Philosophical Transactions of the Royal Society A, 2016Co-Authors: R M Gavioso, Daniele Madonna Ripa, P P M Steur, Christof Gaiser, T Zandt, B Fellmuth, Michael De Podesta, R Underwood, G Sutton, Laurent PitreAbstract:Previous research effort towards the determination of the Boltzmann constant has significantly improved the supporting theory and the experimental practice of several primary thermometry methods based on the measurement of a Thermodynamic property of a macroscopic system at the Temperature of the triple point of water. Presently, experiments are under way to demonstrate their accuracy in the determination of the Thermodynamic Temperature T over an extended range spanning the interval between a few kelvin and the copper freezing point (1358 K). We discuss how these activities will improve the link between Thermodynamic Temperature and the Temperature as measured using the International Temperature Scale of 1990 (ITS-90) and report some preliminary results obtained by dielectric constant gas thermometry and acoustic gas thermometry. We also provide information on the status of other primary methods, such as Doppler broadening thermometry, Johnson noise thermometry and refractive index gas thermometry. Finally, we briefly consider the implications of these advancements for the dissemination of calibrated Temperature standards.
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estimates of the difference between Thermodynamic Temperature and the international Temperature scale of 1990 in the range 118 k to 303 k
Philosophical Transactions of the Royal Society A, 2016Co-Authors: R Underwood, G Sutton, M De Podesta, L Stanger, R L Rusby, P M Harris, Paul Morantz, G MachinAbstract:Using exceptionally accurate measurements of the speed of sound in argon, we have made estimates of the difference between Thermodynamic Temperature, T , and the Temperature estimated using the International Temperature Scale of 1990, T 90 , in the range 118 K to 303 K. Thermodynamic Temperature was estimated using the technique of relative primary acoustic thermometry in the NPL-Cranfield combined microwave and acoustic resonator. Our values of ( T − T 90 ) agree well with most recent estimates, but because we have taken data at closely spaced Temperature intervals, the data reveal previously unseen detail. Most strikingly, we see undulations in ( T − T 90 ) below 273.16 K, and the discontinuity in the slope of ( T − T 90 ) at 273.16 K appears to have the opposite sign to that previously reported.
K Anhalt - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic Temperature of High-Temperature Fixed Points Traceable to Blackbody Radiation and Synchrotron Radiation
International Journal of Thermophysics, 2017Co-Authors: M. Wähmer, K Anhalt, V. R. Gavrilov, R. D. Taubert, Jörg Hollandt, Roman Klein, Reiner Thornagel, I. Grigoryeva, B. B. KhlevnoyAbstract:Absolute spectral radiometry is currently the only established primary thermometric method for the Temperature range above 1300 K. Up to now, the ongoing improvements of high-Temperature fixed points and their formal implementation into an improved Temperature scale with the mise en pratique for the definition of the kelvin, rely solely on single-wavelength absolute radiometry traceable to the cryogenic radiometer. Two alternative primary thermometric methods, yielding comparable or possibly even smaller uncertainties, have been proposed in the literature. They use ratios of irradiances to determine the Thermodynamic Temperature traceable to blackbody radiation and synchrotron radiation. At PTB, a project has been established in cooperation with VNIIOFI to use, for the first time, all three methods simultaneously for the determination of the phase transition Temperatures of high-Temperature fixed points. For this, a dedicated four-wavelengths ratio filter radiometer was developed. With all three thermometric methods performed independently and in parallel, we aim to compare the potential and practical limitations of all three methods, disclose possibly undetected systematic effects of each method and thereby confirm or improve the previous measurements traceable to the cryogenic radiometer. This will give further and independent confidence in the Thermodynamic Temperature determination of the high-Temperature fixed point’s phase transitions.
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dissemination of Thermodynamic Temperature above the freezing point of silver
Philosophical Transactions of the Royal Society A, 2016Co-Authors: Mohamed Sadli, S. Briaudeau, Graham Machin, K Anhalt, F Bourson, D Del Campo, A Diril, O Kozlova, D Lowe, J Mantilla M AmorAbstract:The mise-en-pratique for the definition of the kelvin at high Temperatures will formally allow dissemination of Thermodynamic Temperature either directly or mediated through high-Temperature fixed ...
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Erratum to: Experimental assessment of Thermodynamic Temperature dissemination methods at the highest Temperatures
17th International Congress of Metrology, 2015Co-Authors: Mohamed Sadli, S. Briaudeau, Graham Machin, K Anhalt, F Bourson, D Del Campo, A Diril, O Kozlova, D Lowe, J Mantilla M AmorAbstract:Due to problems that have occurred during the conversion of the article into PDF format, and the resulting loss of many special characters, a new correct version of the article is published below. In the frame of the European Metrology Research Programme (EMRP)-funded joint research project “Implementing the new kelvin” one work package is devoted to the assessment of two different methods of dissemination of the Thermodynamic Temperature. These two methods are the dissemination via high Temperature fixed points (HTFP) with assigned Thermodynamic Temperatures and the dissemination by radiometers or radiation thermometers calibrated in terms of Thermodynamic Temperature. To achieve a thorough assessment of these two distinct dissemination methods two dissemination exercises were organised in the form of comparisons. In one case the circulating artefacts were off-the-shelf high-Temperature fixed point cells with transition Temperatures ranging from 1324 °C to 2474 °C, in the other case absolutely calibrated pyrometers and filter radiometers were compared in the Temperature range 1000 °C to 2500 °C. This work showed that both schemes offered suitable routes for dissemination with competing advantages and drawbacks and would most probably help disseminating Thermodynamic Temperature in the future at the level of 1 K to 2 K uncertainty over the whole Temperature range.
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Experimental assessment of methods of dissemination of the Thermodynamic Temperature at the highest Temperatures
17th International Congress of Metrology, 2015Co-Authors: Mohamed Sadli, S. Briaudeau, Graham Machin, K Anhalt, F Bourson, D Del Campo, A Diril, D Lowe, J Mantilla M Amor, M. J. MartínAbstract:In the frame of the European Metrology Research Programme (EMRP)-funded joint research project “Implementing the new kelvin” one work package is devoted to the assessment of two different methods of dissemination of the Thermodynamic Temperature. These two methods are the dissemination via high Temperature fixed points (HTFP) with assigned Thermodynamic Temperatures and the dissemination by radiometers or radiation thermometers calibrated in terms of Thermodynamic Temperature. To achieve a thorough assessment of these two distinct dissemination methods two dissemination exercises were organised in the form of comparisons. In one case the circulating artefacts were off-the-shelf high-Temperature fixed point cells with transition Temperatures ranging from 1324 °C to 2474 °C, in the other case absolutely calibrated pyrometers and filter radiometers were compared in the Temperature range 1000 °C to 2500 °C. This work showed that both schemes were achievable with competing advantages and drawbacks and would most probably help disseminating Thermodynamic Temperature in the future at the level of 1 K to 2 K uncertainty over the whole Temperature range.
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evaluation and selection of high Temperature fixed point cells for Thermodynamic Temperature assignment
International Journal of Thermophysics, 2015Co-Authors: Yoshiro Yamada, K Anhalt, P Bloembergen, M. Battuello, B. B. Khlevnoy, G Machin, M Matveyev, M Sadli, A D W Todd, T. WangAbstract:A multi-partner project to determine the Thermodynamic Temperatures of a selected set of high-Temperature fixed points based on metal-carbon eutectics is underway as a working group activity within the Comite International des Poids et Mesures. The investigation focuses on four fixed-point types, namely, the three metal-carbon eutectic points of Re-C \((2474\,^{\circ }\hbox {C})\), Pt-C \((1738\,^{\circ }\hbox {C})\), and Co-C \((1324\,^{\circ }\hbox {C})\), and the Cu point \((1084.62\,^{\circ }\hbox {C})\). This paper describes the construction, pre-evaluation, and screening stage of the cells prior to their Thermodynamic Temperature determinations. The construction of the HTFP cells was undertaken by nine national metrology institutes (NMIs) according to instructions laid out in a pre-agreed protocol that ensures production of best quality cells. Four NMIs conducted the evaluation, each for a certain fixed-point type, and screened out cells that did not meet pre-determined selection criteria while assuring sufficient variety in the sources of the cells in the final selected sets. In autumn 2012, the selected cells were successfully passed on to the final stage of the project, the Thermodynamic Temperature measurement, and assignment.
