A waveform synthesizer adopting a superconductor–normal metal–superconductor junction array has been developed, which can generate arbitrary stepwise waveforms with number of quantum-voltage steps up to 1 V level amplitude. As an application the synthesizer, we have built sampling voltmeter that measures differential voltages between sinusoidal produced by semiconductor-based ac source and Josephson waveforms. We carried out extensive measurements for 50 Hz sine wave amplitude, applying...

We report on the realization of 10 quantum Hall devices in series fabricated using epitaxial graphene silicon carbide. Precision measurements with a resistance bridge indicate that quantized across an array at filling factor 2 is equivalent to 5he2 within measurement uncertainty approximately 4 × 10−8. A phase diagram for shows metrological quantization can be achieved magnetic field 6 T and temperature K. This experiment demonstrates possibility timely unchangeable reference various ranges...

We report precision measurements of a 1 MΩ quantum Hall resistance array made GaAs/AlGaAs heterostructure. The quantized at filling factor 2 is directly compared with the standard cryogenic current comparator bridge relative measurement uncertainty 17 × 10−9 95% confidence level. robustness quantization in systematically investigated respect to temperature, magnetic field, and excitation current. observe through repeated thermal cycles that almost unchanged within uncertainty, reflecting...

Abstract A single electron pump was incorporated with a quantum Hall resistance and Josephson voltage for the current evaluation in framework of Ohm’s law. The about 60 pA level amplified by stable amplifier gain 10 3 to induce mV across 1 MΩ array, which compared voltage. calibrated cryogenic comparator bridge. For two different drive frequencies repeated thermal cycles, comparisons demonstrated that averaged over first plateau equal ef within combined uncertainty 0.3 × −6 ( k = 1).

Abstract This paper describes the calibration of a 10 nF capacitance standard traced to DC quantum Hall resistance primary using multi-purpose digital impedance bridge. The bridge can directly compare unlike impedances in fully (FD) mode, so be calibrated by direct comparison against AC standard. measurement ability FD mode was evaluated various angles, and voltage dependencies were improved selecting appropriate for high current arms also an additional injection circuit. Thereby, accuracy...

Two terminal dual source impedance bridge was configured using commercial voltage calibrators. The performance evaluated by measuring 1 to resistance ratio at kHz kΩ and 10 resistors. same used for the (R) inductor (L) capacitor (C) measurements adjusting phase between sources. Then, AC value found from R : C ratio. This simple two proved its reliable versatile measurement capability.

A national traceability chain from dc quantum Hall resistance (QHR) to capacitance has been established at Korea Research Institute of Standards and Science using various impedance standards coaxial bridges. An ac–dc calculable standard nominal value 12.9 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{k}\Omega $ </tex-math></inline-formula> was used as a transfer ac the frequency 1.541 kHz. Two...

A digitally assisted (DA) coaxial bridge, mainly consisting of a ratio transformer and digital voltage sources, was set up in four-terminal-pair (4-TP) configuration for precision impedance measurements. 10:1 capacitance then measured the range 1 pF- μ at kHz using 4-TP DA results were compared to those from existing two-terminal-pair (2-TP) three-terminal (3-T) bridges. The deviations between measurements obtained by different bridges lie few parts 10 <sup...

The Cheongyang (CYG) observatory has been built to measure earth's magnetic field and study prediction of earthquake space weather. equipments the CYG are a 3-axis fluxgate magnetometer, an overhauser effect proton declination/inclination magnetometer data logger. A Cs- <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> He atomic resonance was used correct measured obtained by magnetometer. All measurement were calibrated using standard...

We developed an electron-counting technique for a self-referenced single-electron quantized current source of single-electron-pump system and investigated the fidelity our whole measurement process, including pumping electron counting by transistor (SET) with charge-lock feedback loop. The device was fabricated monolithically using two-dimensional GaAs/AlGaAs hetero-junction. In addition to probability transfer, we also measured noise spectrum SET, from which its charge power Sq derived....

A digital coaxial bridge was evaluated for its frequency extension up to 100 kHz using impedance standards with known reference values. The can be configured in different modes of what are as digitally assisted (DA) or fully (FD) modes, and both were studied. measurement results showed that the FD cannot reach an accuracy below × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-6</sup> at kHz, even 1:1 comparison, unlike DA bridge. Thus,...

This work introduces a switched integration amplifier (SIA)-based photocurrent meter for femtoampere (fA)-level current measurement, which enables us to measure 107 dynamic range of spectral responsivity photometers even with common lamp-based monochromatic light source. We described design considerations and practices about operational amplifiers (op-amps), switches, readout methods, etc., compose stable SIA low offset in terms leakage gain peaking detail. According the design, we made six...

A low DC current source based on the method of charging a capacitor using linear voltage ramp was built for calibration picoammeters and metrological features setup were tested. The measurement uncertainty improved by offset compensation galvanic isolation between personal computer generator via opto-coupling. Using this setup, low-current meter calibrated in range from 10 pA to 1 fA with an 3×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...

The ac/dc magnetic-flux-density (MFD) standard systems were developed for the calibration of magnetometers and test sensors materials. dc MFD is maintained to cover range from 20 µT 2.5 T with expanded uncertainties (k = 2) 4 µT/T 80 µT/T. uncertainty ac 0.2 % in 1 Hz kHz. We had been participated international key comparison achieve equality mutual agreement between institutes results calibrations tests.

This paper describes system setup, based on a Josephson sampling voltmeter for precision power calibration. The waveforms generated by voltage and current sources, which are applied to meter under test, transformed 1-V level signals measured single with uncertainty (k = 2) less than 0.5 μV/V.

We report our progress in the Josephson arbitrary waveform synthesis system KRISS. The is based on pulse-driven junction array, and currently we routinely produce waveforms up to 100 mVrms amplitude with distortions smaller than dBc. Precision results are presented. Our future works will include AC-DC thermal transfer measurement quantum noise source for Johnson thermometry.

The reversal technique in electrical measurements has been generally used to obtain a genuine value of an interesting physical quantity without unwanted signal offset. In the present work, we developed novel cryo-switch made gates on GaAs heterostructure and demonstrate current-reversal operation for single-parameter electron pump. precision measurements, confirmed that current values (i.e., approximately ±12.817 pA) being generated by pump at T = 4.2 K agree well with each other deviation...