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

Sae Woo Nam, S.P. Benz, P.D. Dresselhaus, W.L. Tew, D.R. White, J.M. Martinis
2003 IEEE Transactions on Instrumentation and Measurement  
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
more » ... ross-correlation electronics used in JNT systems. With our prototype JNT system, we have found agreement to two parts in 10 3 with a 1 uncertainty of 1 10 3 between the voltage noise of a 100-resistor in a triple-point Ga cell ( 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 0.3 K (1 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 5 for arbitrary temperatures in the range between 270 and 1000 K.
doi:10.1109/tim.2003.811686 fatcat:bgimhs6lz5gwtenb2eypltp3vu