Improvements in the NIST Johnson Noise Thermometry System

Author

Benz, Samuel P. ; Qu, Jifeng ; Rogalla, Horst ; White, D. Rod ; Dresselhaus, Paul D. ; Tew, Weston L. ; Nam, Sae Woo

Author_Institution

Nat. Inst. of Stand. & Technol., Boulder, CO

Volume

58

Issue

4

fYear

2009

fDate

4/1/2009 12:00:00 AM

Firstpage

884

Lastpage

890

Abstract

We have developed a Johnson noise thermometry (JNT) system that is calibrated by precision waveforms synthesized with a quantized voltage noise source (QVNS). Improvements to the QVNS and the cross-correlation measurement electronics have significantly reduced systematic errors and measurement uncertainty. We describe in detail a number of these improvements, such as amplifier performance and frequency response. We also show details of recent measurements that characterize the nonlinearities and distortion properties of the measurement electronics. Finally, we present an uncertainty analysis and discuss the potential for the QVNS-JNT technique to contribute to the redefinition of Boltzmann´s constant.

Keywords

Boltzmann equation; calibration; noise measurement; thermal noise; thermometers; Boltzmann constant; Johnson noise thermometry system; cross-correlation measurement electronics; measurement electronics; measurement uncertainty; quantized voltage noise source; systematic errors; uncertainty analysis; Boltzmann´s equation; Josephson arrays; correlation; digital–analog conversion; digital–analog conversion; measurement units; noise measurement; quantization; signal synthesis; standards; temperature;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/TIM.2008.2007027

Filename

4685882