SQUIDs for Standards and Metrology

Gallop, John; Piquemal, F.

doi:10.1002/9783527609956.ch9

Cited by 26 publications

(21 citation statements)

References 102 publications

(144 reference statements)

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“…4. generates the full voltage V X , but no flux signal in the SQUID loop. The range-specific κ 0 values are calculated according to (2). The effective weight of a certain bit is finally determined as the difference between the measured κ in case that only this bit is switched ON (DAC at 8000 H ) and κ 0 for the same R L .…”

Section: B Calibrationmentioning

confidence: 99%

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Aspects of Application and Calibration of a Binary Compensation Unit for Cryogenic Current Comparator Setups

Drung

Götz

Pesel

et al. 2013

IEEE Trans. Instrum. Meas.

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We have developed a binary compensation unit for balancing measurement bridges with cryogenic current comparators (CCCs) commonly used in resistance metrology. We present the basic design ideas for the new microcontroller-operated module. It offers balance over a gapless range of resistance ratios of the resistors to be compared. The binary setup allows for convenient calibration when being combined with a binary CCC. The calibration can be performed using the CCC's control electronics and software. Examples of measurements demonstrate the unit's high flexibility and stability of resistance calibration well below one part in 10 9 over a period of 21 hours.

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Section: B Calibrationmentioning

confidence: 99%

“…R ESISTANCE bridges based on cryogenic current comparators (CCCs) are widely used in national metrology institutes [1], [2]. The simplest version of a CCC bridge setup is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Aspects of Application and Calibration of a Binary Compensation Unit for Cryogenic Current Comparator Setups

Drung

Götz

Pesel

et al. 2013

IEEE Trans. Instrum. Meas.

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“…The CCC is a metrological tool with high performance initially developed for the very accurate comparison of resistances. It can be also used as an amplifier with a very accurate known gain (better than 10 −8 ) (Gay,Piquemal and Genevès 2000;Gallop and Piquemal 2006) . It also has an excellent current resolution (around 1 fA/Hz 1/2 in the white noise regime).…”

Section: Experimental Descriptionmentioning

confidence: 99%

The quantum metrology triangle experiment: quantization tests of an electron pump

Sassine

Steck

Feltin

et al. 2010

Sba Controle & Automação

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We present our experimental set-up and discuss the results obtained with the quantum metrological triangle (QMT) experiment. This experiment consists in realizing Ohm's law with the three effects used and investigated in quantum electrical metrology: the Josephson effect (JE), the quantum Hall effect (QHE) and the single electron tunneling effect (SET). The aim is to check the consistency of the phenomenological constants K J , R K and Q X associated with these effects and theoretically expressed with the fundamental constants e and h (elementary charge and Planck constant, respectively). Such an experiment is a contribution for a new definition of electrical units in the International System (SI).

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“…The traceable precision measurement of sub-nA direct currents with room temperature equipment is currently limited to uncertainties of about 10 ppm [5]; an exceptionally low value of 1 ppm was demonstrated with a very sophisticated setup [3]. Up to now, lower uncertainties of the order of 0.1 ppm at 100 pA are believed to be possible only with a cryogenic current comparator (CCC) [6]. CCCs with over 10000 turns were developed for the amplification of currents from SET devices (for example [7,8]).…”

Section: Introductionmentioning

confidence: 99%

“…Basically, a CCC compares two currents with extremely high accuracy [6]. To suppress offset and drift effects, the Applying a CCC to the measurement of a 100 pA direct current lowers the flux linkage drastically; now, the equivalent uncertainty of the zero-flux level should be as low as a few 10 -8…”

Section: Introductionmentioning

confidence: 99%

Ultrastable low-noise current amplifier

Drung

Krause

Becker

et al. 2014

29th Conference on Precision Electromagnetic Measurements (CPEM 2014)

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An ultrastable low-noise current amplifier (ULCA) is presented. The ULCA is a non-cryogenic instrument based on specially designed operational amplifiers and resistor networks. It involves two stages, the first providing a 1000-fold current gain and the second performing a current-to-voltage conversion via an internal 1 MΩ reference resistor or, optionally, an external standard resistor. The ULCA's transfer coefficient is extremely stable versus time, temperature and current amplitude within the full dynamic range of ±5 nA. A low noise level of 2.4 fA/√Hz helps to keep averaging times low at small input currents. A cryogenic current comparator is used to calibrate both input current gain and output transresistance, providing traceability to the quantum Hall effect. Typically, within one day after calibration, the uncertainty contribution from short-term fluctuations of the transresistance is below one part in 10 7 . The long-term stability is expected to be better than one part in 10 5 over a year. A high-precision variant is available that shows a substantially improved stability at the expense of a higher noise level of 7.5 fA/√Hz. The ULCA also allows the traceable generation of small electrical currents or the calibration of high-ohmic resistors.

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SQUIDs for Standards and Metrology

Cited by 26 publications

References 102 publications

Aspects of Application and Calibration of a Binary Compensation Unit for Cryogenic Current Comparator Setups

Aspects of Application and Calibration of a Binary Compensation Unit for Cryogenic Current Comparator Setups

The quantum metrology triangle experiment: quantization tests of an electron pump

Ultrastable low-noise current amplifier

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