Final report on EUROMET.T-K4 (EUROMET Project 820): Comparison of the realizations of the ITS-90 at the freezing points of Al (660.323 °C) and Ag (961.78 °C)

Heyer, Dieter; Noatsch, U.; Tegeler, E.; Anagnostou, M.; Turzo-Andras, E.; Antonsen, I.; Augevicius, V.; Bojkovski, Jovan; Bronnum, A.; Chimenti, V.; Ďuriš, Stanislav; Filipe, Eduarda; Gaita, S.; Gray, J.; Head, D I; Grudniewicz, E.; Ivarsson, Jan; Kalemci, M.; Kerkhof, O.; Lobo, Iarley P.; Németh, S. Z.; Pokhodun, A. I.; Ranostaj, J.; Renaot, E.; Rosenkranz, P. W.; Šmíd, Marek; Steur, P. P. M.; Steiner, Anton; Valin, M. H.; Veliki, Tomislav; Weckström, T.

doi:10.1088/0026-1394/45/1a/03003

Cited by 2 publications

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“…The fixed point cells were constructed in accordance with the procedure outlined in [36]. The design has been tested and validated extensively, through good performance as demonstrated by international key comparisons [37,38].…”

Section: Methodsmentioning

confidence: 99%

A systematic evaluation of contemporary impurity correction methods in ITS-90 aluminium fixed point cells

2017

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The fixed points of the International Temperature Scale of 1990 (ITS-90) are the basis of the calibration of standard platinum resistance thermometers (SPRTs). Impurities in the fixed point material at the level of parts per million can give rise to an elevation or depression of the fixed point temperature of order of millikelvins, which often represents the most significant contribution to the uncertainty of SPRT calibrations. A number of methods for correcting for the effect of impurities have been advocated, but it is becoming increasingly evident that no single method can be used in isolation. In this investigation, a suite of five aluminium fixed point cells (defined ITS-90 freezing temperature 660.323 °C) have been constructed, each cell using metal sourced from a different supplier. The five cells have very different levels and types of impurities. For each cell, chemical assays based on the glow discharge mass spectroscopy (GDMS) technique have been obtained from three separate laboratories. In addition a series of high quality, long duration freezing curves have been obtained for each cell, using three different high quality SPRTs, all measured under nominally identical conditions. The set of GDMS analyses and freezing curves were then used to compare the different proposed impurity correction methods. It was found that the most consistent corrections were obtained with a hybrid correction method based on the sum of individual estimates (SIE) and overall maximum estimate (OME), namely the SIE/Modified-OME method. Also highly consistent was the correction technique based on fitting a Scheil solidification model to the measured freezing curves, provided certain well defined constraints are applied. Importantly, the most consistent methods are those which do not depend significantly on the chemical assay.

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Section: Methodsmentioning

confidence: 99%

A systematic evaluation of contemporary impurity correction methods in ITS-90 aluminium fixed point cells

2017

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“…The measurement procedure was based on that stated in the EUROMET.T-K3 [2] and EURAMET.T-K4 [3] regional key comparisons. Before starting measurements at the fixed points, the SPRTs followed two particular stabilization procedures, allowing stabilities better than 0.3 mK for the one calibrated in the argon-zinc range and 0.5 mK for the one calibrated at the aluminum fixed point.…”

Section: Measurement Proceduresmentioning

confidence: 99%

“…The linkage to the CCT comparisons has been made from the differences obtained between CEM and LACOMET and the differences that CEM obtained in the regional comparisons EUROMET.T-K3 [2] and EUROMET.T-K4 [3] that provided linking to the CCT-K3 [4] and CCT-K4 [5] comparisons.…”

Section: Linkage To the Cct Comparisonsmentioning

confidence: 99%

“…In the case of the freezing point of aluminum, the report to the CCT on key comparison EUROMET.T-K4 [3] gives, in its 17th page, information related to the linkage to the CCT-K3 and CCT-K4 comparisons for the aluminum freezing point with their subsequent uncertainties. This information can be used to link the LACOMET results to the corresponding CCT comparisons:…”

Section: Differences Between Lacomet Cct-k3 and Cct-k4mentioning

confidence: 99%

“…7 and 8 together with the information provided in [3], it is possible to evaluate the uncertainty of these differences:…”

Section: Differences Between Lacomet Cct-k3 and Cct-k4mentioning

confidence: 99%

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Bilateral Comparison Between CEM and LACOMET in the Range from 83.8058 K to 933.473 K, Linking to CCT Comparisons

Campo

García

Solano³

2010

Int J Thermophys

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A bilateral comparison between Centro Español de Metrología (CEM) and Laboratorio Costarricense de Metrología (LACOMET) in the range from 83.8058 K to 933.473 K was carried out during 2009, and it is aimed to provide linkage of the CCT key comparisons K3 and K4 to LACOMET. This comparison gives support to the calibration measurement capabilities requested by LACOMET. The participation of CEM in the EURAMET regional comparisons EUROMET-T.K3 and EUROMET-T.K4 is the basis of the link. Two 25 standard platinum resistance thermometers (SPRTs) were used as travelling standards and were hand carried. One of them was used only in the aluminum freezing point while the other one covered the remaining fixed points. At the temperature of the argon triple point (83.8058 K), CEM performed the measurements in an argon triple-point apparatus, but LACOMET calibrated the SPRT at a temperature close to the argon point using a liquid-nitrogen boiling-point apparatus. Both SPRTs were provided by LACOMET, and LACOMET measured them before and after CEM. The SPRTs showed no significant drifts during the comparison. The results for both laboratories agreed within their expanded uncertainties and are summarized. A proposal for the linkage to the results of CCT-K3 and CCT-K4 is presented.

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Final report on EUROMET.T-K4 (EUROMET Project 820): Comparison of the realizations of the ITS-90 at the freezing points of Al (660.323 °C) and Ag (961.78 °C)

Cited by 2 publications

References 0 publications

A systematic evaluation of contemporary impurity correction methods in ITS-90 aluminium fixed point cells

A systematic evaluation of contemporary impurity correction methods in ITS-90 aluminium fixed point cells

Bilateral Comparison Between CEM and LACOMET in the Range from 83.8058 K to 933.473 K, Linking to CCT Comparisons

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