The vapour pressure of caesium between 370  C and 660  C

Hill, Kathryn; Gotoh, Masahiko

doi:10.1088/0026-1394/33/4/4

Cited by 11 publications

(6 citation statements)

References 8 publications

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“…This effective area value is only 3.3 ppm larger than the manufacturer-supplied value of the piston effective area from 1991, which itself carried a 13 ppm uncertainty. The acceleration due to gravity at the height of the piston gauge effective reference plane, g gravity , was re-determined in 2016 and found to be 9.8061336(10) m·s −2 , slightly larger than the value previously used for experiments performed in this laboratory [18,23,24]. Combining the new piston effective area and gravitation acceleration values results in a change of the pressure realization of less than 2 ppm relative to that used previously at NRC with the same equipment [23].…”

Section: Cryostat and Thermometrymentioning

confidence: 81%

NRC Microwave Refractive Index Gas Thermometry Implementation Between 24.5 K and 84 K

Rourke

2017

Int J Thermophys

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Vous avez des questions?Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.Access and use of this website and the material on it are subject to the Terms and Conditions set forth at NRC microwave refractive index gas thermometry implementation between 24.5 K and 84 K Rourke, P. M. C. https://publications-cnrc.canada.ca/fra/droits L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site Abstract The implementation of microwave refractive index gas thermometry at the National Research Council between 24.5 K and 84 K is reported. A new gas-handling system for accurate control and measurement of experimental gas pressure has been constructed and primary thermometry measurements have been performed using a quasi-spherical copper resonator and helium gas at temperatures corresponding to three defining fixed points of the International Temperature Scale of 1990 (ITS-90). These measurements indicate differences between the thermodynamic temperature T and ITS-90 temperature T 90 of (T − T 90 ) = −0.60 ± 0.56 mK at T 90 = 24.5561 K, (T − T 90 ) = −2.0 ± 1.3 mK at T 90 = 54.3584 K, and (T − T 90 ) = −4.0 ± 2.9 mK at T 90 = 83.8058 K. The present results at T 90 = 24.5561 K and T 90 = 83.8058 K agree with previously reported measurements from other primary thermometry techniques of acoustic gas thermometry and dielectric constant gas thermometry, and the result at T 90 = 54.3584 K provides new information in a temperature region where there is a gap in other recent data sets.Keywords Primary thermometry · Thermodynamic temperature · T − T 90 · Polarizing gas thermometry · Refractive index gas thermometry · RIGT 1 IntroductionThe International Temperature Scale of 1990 (ITS-90) [1, 2] is a practical temperature scale used worldwide to approximate thermodynamic temperature T by ITS-90 temperature T 90 . The ITS-90 was created based on the best thermodynamic temperature measurements available in 1990, mainly those performed using the constant-volume gas thermometry (CVGT) technique.Since 1990, however, new measurements have indicated that T 90 deviates from T over a broad temperature range [3,4]. The most accurate (T − T 90 ) measurements in which R = N A k B is the molar gas constant, N A is the Avogadro constant, k B is the Boltzmann constant, T is the thermodynamic temperature, and B ρ , C ρ and D ρ are density virial coefficients. The presence of T in Eq. 4 is the key to experimentally determining the thermodynamic temperature of the gas.

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Section: Cryostat and Thermometrymentioning

confidence: 81%

NRC Microwave Refractive Index Gas Thermometry Implementation Between 24.5 K and 84 K

Rourke

2017

Int J Thermophys

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“…A few things still remain to be tested for both Cs-PCHP and Na-PCHP, such as comparison of different wells and testing repeatability of Cs-PCHP upon furnace reheating and checking whether axial temperature homogeneity of Na-PCHP can be further improved upon reheating the chimney to melt any frozen sodium left, to name a few. And although we are still a few experiments away from the bold proposal we put forward in the abstract -namely, having a comparison apparatus in 600 K -1300 K temperature range with an exceptional temperature uniformity, stability and repeatability -the road to it is clear and lies through a better design of the PCHP itself: using Cs-PCHP with a central hole for the temperature equalizing block as in [3] for better axial and radial temperature uniformity and purchasing a one end closed Na-PCHP for better axial temperature uniformity. The new simplified gas handling system used to control the pressure in both Cs-PCHP and Na-PCHP is only the first step in the right direction.…”

Section: Nrc Pressure Controlled Heat Pipe Furnace: Future Workmentioning

confidence: 99%

Caesium- and sodium-filled pressure controlled heat pipe at NRC

Dedyulin

Gotoh

2023

J. Phys.: Conf. Ser.

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What if you could tune the temperature of the fixed point used to calibrate your thermometer continuously between the freezing points of zinc (692.677 K) and silver (1234.93 K) while maintaining the uniform temperature environment (±10 mK) along 20 cm zone for hours at a time and with an uncertainty approaching a fraction of a mK? We are aiming to do exactly that by using a set of caesium- and sodium-filled pressure controlled heat pipes previously established at NRC. The original pressure controlled heat pipe furnaces have been recommissioned with a number of changes to improve their function as a calibration by comparison apparatus. In particular, the new gas handling system capable of controlling the pressure within ±4 ppm was installed side by side with the previously reported one. In this paper, we show the temperature performance of legacy NRC caesium- and sodium-filled pressure controlled heat pipes when connected to the new gas handling system.

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“…This technique delivered outstanding temperature stability and a thermowell immersion gradient of +/-1 mK over 25 cm was realized. The system remained in operation until 1995 and was used for measuring the vapour pressure curve of Na and Cs and for producing the reference tables for platinum-gold thermocouples [40][41][42][43][44].…”

Section: National Research Council Of Canada (Nrc)mentioning

confidence: 99%