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TitleProgress in noise thermometry at 505 K and 693 K using quantized voltage noise ratio spectra
Publication TypeJournal Article
Year of Publication2010
AuthorsTew, W.L., Benz S.P., Dresselhaus P.D., Coakley K.J., Rogalla H., White D.R., and Labenski J.R.
JournalInternational Journal of Thermophysics
Pagination1719 - 1738
Date Published2010
ISSN0195928X (ISSN)
KeywordsAverage power, Freezing, Freezing point, International Temperature Scale of 1990, ITS-90, Johnson noise, Johnson noise thermometry, Low frequency, New results, Noise temperature, Noise thermometers, Noise thermometry, Platinum, Power spectral density, Power spectrum, Power-spectra, Present value, Spectral density, Standard platinum resistance thermometers, Synthesized noise, Technical advances, Temperature, Thermometers, Three-parameter models, Time constants, Tin, Uncertainty analysis, Voltage noise, Zinc
AbstractTechnical advances and new results in noise thermometry at temperatures near the tin freezing point and the zinc freezing point using a quantized voltage noise source (QVNS) are reported. The temperatures are derived by comparing the power spectral density of QVNS synthesized noise with that of Johnson noise from a known resistance at both 505 K and 693 K. Reference noise is digitally synthesized so that the average power spectra of the QVNS match those of the thermal noise, resulting in ratios of power spectra close to unity in the low-frequency limit. Three-parameter models are used to account for differences in impedance-related time constants in the spectra. Direct comparison of noise temperatures to the International Temperature Scale of 1990 (ITS-90) is achieved in a comparison furnace with standard platinum resistance thermometers. The observed noise temperatures determined by operating the noise thermometer in both absolute and relative modes, and related statistics together with estimated uncertainties are reported. The relative noise thermometry results are combined with results from other thermodynamic determinations at temperatures near the tin freezing point to calculate a value of T - T 90 = +4(18) mK for temperatures near the zinc freezing point. These latest results achieve a lower uncertainty than that of our earlier efforts. The present value of T - T 90 is compared to other published determinations from noise thermometry and other methods. © Springer Science+Business Media, LLC 2010.

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