• DOI:10.1109/TIM.2003.811686
• Corpus ID: 31209802

Johnson noise thermometry measurements using a quantized voltage noise source for calibration

@article{Nam2003JohnsonNT,
  title={Johnson noise thermometry measurements using a quantized voltage noise source for calibration},
  author={Sae Woo Nam and Samuel P. Benz and Paul D. Dresselhaus and Weston L. Tew and Rod White and John M. Martinis},
  journal={IEEE Trans. Instrum. Meas.},
  year={2003},
  volume={52},
  pages={550-554}
}

• S. Nam, S. Benz, +3 authors J. Martinis
• Published 5 June 2003
• Physics
• IEEE Trans. Instrum. Meas.

We describe a new approach to Johnson noise thermometry (JNT) that exploits recent advances in Josephson voltage standards and digital signal processing techniques. Currently, high-precision thermometry using Johnson noise is limited by the nonideal performance of electronic measurement systems. By using the perfectly quantized voltage pulses from a series array of Josephson junctions, any arbitrary broadband waveform can be synthesized and used as a calculable noise source for calibrating the cross-correlation electronics used in JNT systems. With our prototype JNT system, we have found agreement to two parts in 10/sup 3/ with a 1/spl sigma/ uncertainty of 1/spl times/10/sup -3/ between the voltage noise of a 100-/spl Omega/ resistor in a triple-point Ga cell (T/sub 90/= 302.916 K) and a pseudo-noise waveform with the same average power that is synthesized by a quantized voltage noise source. We estimate the temperature of the resistor to be 302.5 K/spl plusmn/0.3 K (1/spl sigma/ uncertainty based on the uncertainty from the cross-correlation). With better characterization of our JNT system, we expect to achieve relative accuracies of parts in 10/sup 5/ for arbitrary temperatures in the range between 270 and 1000 K.