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.

Search Publications by: Weston L. Tew (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 26 - 50 of 78

Systematic Error Resolved in NIST Johnson Noise Thermometer

August 24, 2014
Author(s)
Alessio Pollarolo, Weston L. Tew, Horst Rogalla, Samuel P. Benz
In the Johnson Noise Thermometry approach, Boltzmann’s constant k is obtained as the ratio of the noise power measured across a sense resistor at the triple point of water and the noise power measured for a synthesized reference waveform. The reference

Improvements to the Johnson Noise Thermometry System for Measurements at 505 – 800 K

September 12, 2013
Author(s)
Weston L. Tew, Kazuaki Yamazawa, Samuel P. Benz, Alessio Pollarolo, Horst Rogalla, Paul D. Dresselhaus
The National Institute of Standards and Technology (NIST) is currently using Johnson noise thermometry (JNT) to determine the deviations of the International Temperature Scale of 1990 (ITS-90) from the thermodynamic temperature in the range of 505–933 K

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