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Search Publications by: Weston L. Tew (Fed)

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Displaying 26 - 50 of 74

Johnson-noise thermometry based on a quantized-voltage noise source at NIST

September 11, 2013
Author(s)
Alessio Pollarolo, Tae H. Jeong, Samuel Benz, Paul Dresselhaus, Horst Rogalla, Weston L. Tew
Johnson Noise Thermometry is an electronic approach to measuring temperature. For several years, NIST has been developing a switching-correlator-type Johnson-noise thermometer that uses a quantized voltage noise source as an accurate voltage reference

The Residual Resistance Ratio of High-Purity Platinum

August 22, 2011
Author(s)
Weston L. Tew, William E. Murdock, Michal J. Chojnacky, Dean C. Ripple
High-purity platinum wire is produced for use in both Standard Platinum Resistance Thermometers (SPRTs) and type S and type R thermocouples. The resistance ratio W(T90) and thermoelectric characteristics of the wire are a function of chemical purity and

An electronic measurement of the Boltzmann constant

March 30, 2011
Author(s)
Samuel P. Benz, Alessio Pollarolo, Jifeng Qu, Horst Rogalla, Chiharu Urano, Weston L. Tew, Paul D. Dresselhaus, D. R. White
The Boltzmann constant was measured by comparing the Johnson noise of a resistor at the triple point of water with a quantum-based voltage reference signal generated with a superconducting Josephson-junction waveform synthesizer. The measured value of k =

Improvements in the NIST Johnson Noise Thermometry System

April 1, 2009
Author(s)
Samuel P. Benz, Jifeng Qu, Horst Rogalla, D. R. White, Paul D. Dresselhaus, Weston L. Tew, Sae Woo Nam
We have developed a Johnson noise thermometry (JNT) system that is calibrated by precision waveforms synthesized with a quantized voltage noise source (QVNS). Significant improvements to the QVNS and the cross-correlation measurement electronics have

Measurement Time and Statistics for a Noise Thermometer With a Synthetic-Noise Reference

August 1, 2008
Author(s)
David R. White, Samuel Benz, J Labenski, Sae Woo Nam, Jifeng Qu, H Rogalla, Weston L. Tew
This paper describes methods for reducing the statistical uncertainty in measurements made by noise thermometers using digital cross correlators, and in particular, for thermometers using pseudorandom noise for the reference signal. First, a discrete

Adjustments to the NIST Realization of the ITS-90 from 5 K to 24.5561 K

May 1, 2008
Author(s)
Weston L. Tew, Christopher W. Meyer
Recent clarifications issued by the Consultative Committee on Thermometry (CCT) for the definitions of the equilibrium hydrogen (e-H2) triple points (TPs) and vapor-pressure points (VPs) have resulted in adjustments to the NIST-disseminated ITS-90 (T90) in

Resistance-Based Scaling of LF-and MF-Band Thermal Noise Powers

April 1, 2007
Author(s)
John Labenski, Weston L. Tew, Sae Woo Nam, Samuel P. Benz, Paul D. Dresselhaus, Charles J. Burroughs
A conventional technique for scaling thermal noise power in Johnson Noise Thermometry (JNT) is via resistance ratios. We describe measurements in the low to medium frequency (LF/MF) bands using this approach via correlation methods in the frequency domain

Acoustic Thermometry: New Results From 273 K to 77 K and Progress Towards 4 K

January 1, 2006
Author(s)
Laurent Pitre, Michael R. Moldover, Weston L. Tew
We used a quasi-spherical cavity as an acoustic and microwave resonator to measure the thermodynamic temperatures T of the triple points of mercury, argon, neon, and equilibrium hydrogen, and to measure the difference T - T90, in the range 7 K to 273 K.

Isotopic and Other Influences of the Realization of the Triple Point of Hydrogen

August 1, 2005
Author(s)
B Fellmuth, L Wolber, Y Hermier, F Pavese, PPM Steur, I Peroni, A Szmyrka-Grzebyk, L Lipinski, Weston L. Tew, H Nakano, H Sakurai, O Tamura, D I. Head, K D. Hill, A G. Steele
Within an international collaboration of the eight metrological institutes represented by the authors, the dependence of the triple-point tmeperature of equilibrium, hydrogen on the deuterium content at low concentrations has been precisely determined so

Progress on Johnson Noise Thermometry using a Quantum Voltage Noise Source for Calibration

April 1, 2005
Author(s)
Sae Woo Nam, Samuel P. Benz, Paul D. Dresselhaus, Charles J. Burroughs, Weston L. Tew, D. R. White, John M. Martinis
We describe our progress towards a high-precision measurement of temperature using Johnson noise. Using a Quantized Voltage Noise Source (QVNS) based on the Josephson effect as a calculable noise source, we have been able to measure the ratio of the

CCT Key Comparison No 1 (CCT-K1): Realisations of the ITS-90, 0.65 K to 24.5561 K, Using Rhodium-Iron Resistance Thermometers

June 1, 2004
Author(s)
R L. Rusby, Christopher W. Meyer, Weston L. Tew, D I. Head, K D. Hill, O Tamura, P A. de Groot, B Fellmuth, A Storm, A Peruzzi, J Engert, D N. Astrov, Y Dedikov, G A. Kytin
At its meeting in 1996 the CCT initiated five Key Comparisons to test the equivalence of realisations of the ITS-90 between National Measurement Institutes. CCT-K1 covers the temperature range from 0.65 K to 24.5561 K, in which the ITS-90 is defined by

Johnson Noise Thermometry Using a Quantum Voltage Noise Source for Calibration

June 1, 2004
Author(s)
Sae Woo Nam, Samuel P. Benz, Paul D. Dresselhaus, Weston L. Tew, D. R. White, John M. Martinis
We describe our progress towards a high-precision measurement of temperature using Johnson noise. Using a Quantized Voltage Noise Source (QVNS) based on the Josephson effect as a calibrated noise source, we have been able to measure the gallium and water

Johnson Noise Thermometry Measurements Using a Quantized Voltage Noise Source for Calibration

April 1, 2003
Author(s)
Sae Woo Nam, Samuel Benz, Paul Dresselhaus, Weston L. Tew, David R. White, John M. Martinis
We describe a new approach to Johnson Noise Thermometry(JNT) that takes advantage of recent advances in Josephson voltage standards and digital signal processing techniques. Currently, high-precision thermometry using Johnson noise is limited by the non