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Search Publications by: Weston L. Tew (Fed)

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Displaying 76 - 100 of 151

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