Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Recent Progress in Noise Thermometry at 505 K and 693 K Using Quantized Voltage Noise Ratio Spectra

Published

Author(s)

Weston L. Tew, Paul D. Dresselhaus, Kevin J. Coakley, H Rogalla, D. R. White, J Labenski

Abstract

We report on technical 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). The temperatures are derived in a series of separate measurements comparing the spectral power 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 power ratio spectra which are close to unity in the low-frequency limit. Three-parameter models are used to account for differences in impedance-related time constants. Direct comparison of noise temperatures to ITS-90 is achieved in a comparison furnace with standard platinum resistance thermometers. We report on the observed noise temperatures determined by operating the noise thermometer in both absolute and relative modes, and related statistics together with estimated uncertainties. 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 T90 =+4 +/- 18 mK for temperatures near the zinc freezing point. These new results achieve a lower uncertainty than that of our earlier efforts and we compare the present value of T T90 to other published determinations from noise thermometry and other methods.
Citation
International Journal of Thermophysics
Volume
31
Issue
8-9

Keywords

ITS-90, Johnson Noise Thermometry, Synthesized Noise, Temperature

Citation

Tew, W. , Dresselhaus, P. , Coakley, K. , Rogalla, H. , White, D. and Labenski, J. (2010), Recent Progress in Noise Thermometry at 505 K and 693 K Using Quantized Voltage Noise Ratio Spectra, International Journal of Thermophysics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=905427 (Accessed October 24, 2021)
Created September 6, 2010, Updated February 19, 2017