Cryocooled primary voltage standard system

Tang, Yang; Hunt, Richard A.; Robertazzi, R. P.; Fisher, M.; Coughlin, J.; Patt, R.; Track, E.K.; Potenziani, E.

doi:10.1109/19.571826

Cited by 20 publications

(4 citation statements)

References 1 publication

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“…The following non-exhaustive list gives the composition of jj that have been studied for the realization of JVS. SIS arrays were realized with Nb/NbO x /PbInAu (A) [15,17,[24][25][26][27][28][29]. The first 1 V array had a total of 1474 PbInAu/PbO x /PbAu (B) SIS jj driven at 90 GHz [30].…”

Section: Materials and Geometrymentioning

confidence: 99%

“…Most junctions are made of niobium for the superconducting layers and thus have to be operated below 9 K independent of the nature of the material used for the insulator or normal layer. Usually liquid helium is used as a cryogen but some experiments have shown very good agreement with cryocoolerbased systems for which the temperature set point can be higher or lower than the equilibrium temperature of liquid helium [23,25]. Stacked SNS junctions have exhibited useful Shapiro steps at 6 K [22].…”

Section: Temperaturementioning

confidence: 99%

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A review of Josephson comparison results

Wood

Solve

2009

Metrologia

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In March 2009, the Consultative Committee for Electricity and Magnetism (CCEM) reviewed and re-endorsed its recommendations originally proposed during its 25th meeting (April 2007) for changes in the SI electrical units (Recommendation E-1). Among its considerations, the document stated that the representation of the volt using the Josephson effect and the conventional value of the Josephson constant, K J−90 , has provided practical, accessible, reproducible, low noise and highly linear references worldwide since 1990. We summarize the measurement results of comparisons between Josephson voltage standards that help support this statement, especially concerning the accuracy and the simplicity of the Josephson relationship between voltage and frequency. We also detail a list of influence parameters and the ranges over which the Josephson relationship has been tested.

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Section: Materials and Geometrymentioning

confidence: 99%

Section: Temperaturementioning

confidence: 99%

A review of Josephson comparison results

Wood

Solve

2009

Metrologia

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“…Conventional Josephson voltage standards based on drycooled hysteretic Josephson junctions (JJs) are in use for many years [1,2] and there were efforts to apply such cooling also for programmable Josephson voltage standards (PJVS) [3]. These arrays are very attractive for ac calibrations due to the programmable output voltage.…”

Section: Introductionmentioning

confidence: 99%

A dry-cooled AC quantum voltmeter

Schubert

Starkloff²,

Peiselt

et al. 2016

Supercond. Sci. Technol.

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The paper describes a dry-cooled AC quantum voltmeter system operated up to kilohertz frequencies and 7 V rms. A 10 V programmable Josephson voltage standard (PJVS) array was installed on a pulse tube cooler (PTC) driven with a 4 kW air-cooled compressor. The operating margins at 70 GHz frequencies were investigated in detail and found to exceed 1 mA Shapiro step width. A key factor for the successful chip operation was the low on-chip power consumption of 65 mW in total. A thermal interface between PJVS chip and PTC cold stage was used to avoid a significant chip overheating. By installing the cryocooled PJVS array into an AC quantum voltmeter setup, several calibration measurements of dc standards and calibrator ac voltages up to 2 kHz frequencies were carried out to demonstrate the full functionality. The results are discussed and compared to systems with standard liquid helium cooling. For dc voltages, a direct comparison measurement between the dry-cooled AC quantum voltmeter and a liquid-helium based 10 V PJVS shows an agreement better than 1 part in 1010.

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“…[3][4][5][6][7] Output voltage from a JJ array or a programmable JJ array, in principle, has quantum accuracy and is used as quantum standard of voltage, because the induced voltage (U) is directly proportional to frequency (f) of microwave: U = n o f, where o = h/2e 2.067 × 10 −15 Wb, h is Planck's constant, e is the elementary charge, and n is an integer. [8][9][10][11][12][13][14][15] They can be used as DACs, however, ratio of maximum output voltage to voltage interval or dynamic range for these devices is around 50 000 because the interval or least significant bit is not easily adjustable.…”

mentioning

confidence: 99%

Note: Increasing dynamic range of digital-to-analog converter using a superconducting quantum interference device

Nakanishi

2014

Review of Scientific Instruments

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Responses of a superconducting quantum interference device (SQUID) are periodically dependent on magnetic flux coupling to its superconducting ring and the period is a flux quantum (Φo = h/2e, where h and e, respectively, express Planck's constant and elementary charge). Using this periodicity, we had proposed a digital to analog converter using a SQUID (SQUID DAC) of first generation with linear current output, interval of which corresponded to Φo. Modification for increasing dynamic range by interpolating within each interval is reported. Linearity of the interpolation was also based on the quantum periodicity. A SQUID DAC with dynamic range of about 1.4 × 10(7) was created as a demonstration.

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Cryocooled primary voltage standard system

Cited by 20 publications

References 1 publication

A review of Josephson comparison results

A review of Josephson comparison results

A dry-cooled AC quantum voltmeter

Note: Increasing dynamic range of digital-to-analog converter using a superconducting quantum interference device

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