| DOI | Resolve DOI: https://doi.org/10.1063/1.1627201 |
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| Author | Search for: Ma, C. K. |
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| Sponsor | Search for: AIP |
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| Format | Text, Article |
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| Conference | Eighth International Temperature Symposium, October 21-24, 2002, Chicago, Illinois, United States |
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| Abstract | In the precise realization of the freezing point of copper, it is necessary to account for the temperature drop across the wall of the cavity of the copper‐freezing‐point blackbody. This temperature drop (∼1 mK) is difficult to measure and is usually estimated by theoretical calculations. We envision that it may be measurable after accentuation in a suitably devised experiment. This paper is an account of our endeavor to measure the temperature drop. In our first experiment we constructed a number of cylindrical cavities, each having a circular base of non‐uniform thickness. During freezing or melting we anticipated that the temperature distribution of the base would reflect the varying temperature drop due to the varying thickness. Results show that the effect of the non‐uniform surface condition dominates over that of the varying thickness, making the latter undetectable. In our second experiment we constructed four atypical copper‐freezing‐point blackbodies which are practically identical to one another except that the wall thickness is uniform but different from one another. We compare the melting points of these blackbodies with the melting point of a reference blackbody. Results generally show an increase of temperature drop with increasing wall thickness. We apply the results to a more typical copper‐freezing‐point blackbody and estimate the temperature drop at the centre of the base to be 1.1 ± 0.6 mK (1 σ). A comparable figure for a similar cavity, based on the upper and lower limits calculated by detail balancing of radiative and conductive heat flows in opposing limiting conditions, is 1.2 ± 0.5 mK. |
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| Publication date | 2003-09-29 |
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| Publisher | AIP Publishing LLC |
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| Series | |
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| Language | English |
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| Peer reviewed | Yes |
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| NRC number | NRC-INMS-223 |
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| NPARC number | 5763819 |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | 732324ae-d648-4856-8f7a-0138f7e7f56e |
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| Record created | 2009-03-29 |
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| Record modified | 2024-02-14 |
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