1

Plenary Talk Presented at the Applied Superconductivity Conference, 

Denver, CO on Sept. 9, 2016

Video available at Voltage Metrology with Superconductive Electronics -

Voltage Metrology with Superconductive Electronics

S.P. Benz, National Institute of Standards and Technology, Boulder, Colorado, 80305 USA

Contact e-mail: benz@nist.gov

Josephson’s discovery in 1962 of the quantum behavior of superconducting junctions enabled a revolution 

in precision voltage measurement that replaced electrochemical cells, which are artifact standards whose 

behavior depends upon environmental conditions, with quantum-based standards, whose values are 

intrinsically accurate and can be reproduced anywhere. Many technological advances in junction 

fabrication, superconducting integrated circuit technology, bias techniques, and instrumentation were 

required to achieve the present generation of practical ac and dc voltage standard systems. Quantum-based 

10 V programmable Josephson voltage standards and 2 V rms Josephson arbitrary waveform synthesizers are now 

used in a wide range of metrology applications, calibration laboratories and precision measurement experiments. 

For metrology, these systems are used for measuring dc and ac voltage, ac power, and impedance. They are also 

key instruments in precision measurement experiments of mass and temperature to determine more accurate values 

of the Planck and Boltzmann constants. I will review major technological advances with a focus on the 

superconducting devices and circuits and describe the current state-of-the-art research and development in 

superconductive analog and digital circuits that may lead to improved precision measurement of voltage and lowdistortion signals for rf communications.

References

1. B. D. Josephson, “Possible new effects in superconductive tunneling,” Phys. Lett., vol. 1, pp. 251-253, July

1962.

2. J. Niemeyer, “Josephson voltage standards,” in Handbook of Applied Superconductivity, vol. 2, B. Seeber, ed.,

Institute of Physics, Philadelphia, PA, 1998, pp. 1813-34.

3. S. P. Benz, “Synthesizing accurate voltages with superconducting quantum-based standards,” IEEE Instr. 

Meas. Magazine, June 2010, pp. 8-13.

4. H. Yamamori, et al., “A 10V programmable Josephson voltage standard circuit with a maximum voltage of 

20 V”, Supercond. Sci. Technol., vol. 21, 105007-6, July 2008, DOI:10.1088/0953-2048/21/10/105007.

5. F. Müller, et al., “NbSi Barrier Junctions Tuned for Metrological Applications up to 70 GHz: 20 V Arrays for 

Programmable Josephson Voltage Standards,” IEEE Trans. Appl. Supercond., vol. 24, pp. 1101005-5, Feb. 

2014, DOI: 10.1109/TASC.2013.2284834. 

6. A. Rüfenacht, et al., “Cryocooled 10 V programmable Josephson voltage standard,” IEEE Trans. Inst. Meas., 

vol. 64, pp. 1477-1482, June 2015, DOI: 10.1109/TIM.2014.2374697.

7. N. E. Flowers-Jacobs, et al., "Two-volt Josephson arbitrary waveform synthesizer using Wilkinson dividers," 

IEEE Trans. Appl. Supercond., in press, DOI: 10.1109/TASC.2016.2532798.

8. Jifeng Qu, et al., “Improved electronic measurement of the Boltzmann constant by Johnson noise 

Thermometry,” Metrologia, vol. 52, pp. 441-451, June 2015, DOI: 10.1088/0026-1394/50/5/441

9. Urano, et al., “Johnson noise thermometry based on Integrated quantum voltage noise source,” IEEE Trans. 

Appl. Supercond., vol. 26, pp. 1800305-5, April 2016, DOI: 10.1109/TASC.2016.2524472.

Acknowledgements

I thank and recognize all current and former members and guest researchers of the NIST Quantum Voltage Project 

and collaborators and colleagues from national and international measurement institutes and universities, all of 

whom have contributed to this field of research.