Assembly and Study of Different Mercury Cells with Known Impurity Content and Isotopic Composition

Campo, D. del; Chimenti, V.; Reyes, Jesús; Castrillón, J. A. Rodríguez; Moldován, Mariella; Alonso, J. Ignacio García

doi:10.1007/s10765-007-0344-2

Cited by 7 publications

(12 citation statements)

References 7 publications

(8 reference statements)

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“…If the variations in natural abundance are correlated with the fractionation factors (as they usually are), then there could be as much as 100 µK variation between cells due to isotopic effects. Preliminary results for mercury suggest any effect is probably below 100 µK [22], but further work is required for both tin and mercury.…”

Section: Isotopic Effectsmentioning

confidence: 98%

Uncertainties in the SPRT Subranges of ITS-90: Topics for Further Research

White¹,

Ballico

Campo

et al. 2010

Int J Thermophys

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The CCT has completed the guide summarizing the uncertainties in the realization of the SPRT subranges of ITS-90 between the triple point of neon (24.5561 K) and the freezing point of silver (961.78 • C). This article identifies aspects of standard platinum resistance thermometry where either data or models are lacking and further research is required. In the calibration of SPRTs, the two main concerns are the need for data on liquidus slopes for the different impurities in the fixed points and improved understanding of the impact of the thermal environment of the fixed point on the realized temperature. In the use of SPRTs, the two largest sources of uncertainty are Types 1 and 3 non-uniqueness and oxidation. The causes of Type 3 non-uniqueness are not yet understood, especially at low temperatures, and there is a paucity of data for the high-temperature subranges. In respect of oxidation, there is a need for validation of the models developed in the 1980s, especially in light of the reduced partial pressure of oxygen used in modern SPRTs. A range of other effects including vacancy effects in SPRTs, isotopic effects in fixed points, and improved statistical methods are discussed.

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Section: Isotopic Effectsmentioning

confidence: 98%

Uncertainties in the SPRT Subranges of ITS-90: Topics for Further Research

White¹,

Ballico

Campo

et al. 2010

Int J Thermophys

Self Cite

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“…We also used information provided by our mercury supplier (Almaden mine) and the results of chemical analysis of previous assembled cells [4]. The binary phase diagrams of Hg with all these metals are also useful tools in this experiment [5].…”

Section: Doping Proceduresmentioning

confidence: 99%

“…The second choice was Ag due to the fact that it is the most dominant impurity found in the mercury samples analyzed in our laboratory [4]. Before starting the doping process, the binary Hg-Zn phase diagram [6] and the Hg-Ag phase diagram [7] were studied.…”

Section: Doping Proceduresmentioning

confidence: 99%

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Doping Experiments in Mercury Triple-Point Cells

2011

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Mercury is one of the fixed points that can be obtained with higher purity, and it also can be measured with high accuracy; this turns impurities into one of the dominant sources of uncertainty. This article summarizes the first steps that CEM has carried out to start an exhaustive study of the influence of impurities on the triplepoint-of-mercury temperature by means of doping experiments. The basis to choose the doping elements are stated, the procedure to dope the cells is described together with the careful performance of the weighing of the alloy components, and the results obtained for Zn and Ag are also shown.

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“…After cleaning the borosilicate cell material, each cell has been filled by the pour-and-pump method. The details regarding cleaning and fabrication can be found in [4], and some photographs taken during pumping and sealing of the mercury cell are shown in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Methods for Determining the Impurity Concentration in Mercury Cells

2011

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The uncertainty arising from chemical impurities is the principle contribution in the uncertainty budget of primary level temperature measurements. Impurities in any substance generally decrease the freezing (or triple) point temperature of a substance, and their influence is governed primarily by their behavior at low concentrations in the host material. The depression in temperature due to impurities is theoretically expressed by Raoult's law which, at final analysis, expresses the linearity between T (T observed − T pure ) and the inverse of the melted fraction (1/F). Recently, TUBITAK UME carried out a new project on the construction of new reference mercury fixed-point cells. Within the scope of this study, three different sets of mercury cells with different purity values were fabricated. Three methods were employed to assess the impurity concentration in the cells. The first method is known as the mole fraction sum of impurity components, and the chemical assays form the basis for this kind of assessment. The second method of evaluation is based on a 1/F versus T curve, and the slope values obtained from these curves are important. The final method is to directly compare the new cells with a national (or reference) standard mercury cell. The results obtained from three methods of evaluation showed consistency in terms of qualitative analysis.

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Assembly and Study of Different Mercury Cells with Known Impurity Content and Isotopic Composition

Cited by 7 publications

References 7 publications

Uncertainties in the SPRT Subranges of ITS-90: Topics for Further Research

Uncertainties in the SPRT Subranges of ITS-90: Topics for Further Research

Doping Experiments in Mercury Triple-Point Cells

Assessment of Methods for Determining the Impurity Concentration in Mercury Cells

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