M Nakanishi et al 2002 Metrologia 39 207 doi:10.1088/0026-1394/39/2/8
M Nakanishi, J Kinoshita, T Endo, Z Zhang, H Shao, Q He and B Liang
Show affiliationsThe resistance standard maintained at the Electrotechnical Laboratory (ETL, Japan) is based on the resistance of the second plateau of the quantized Hall resistance, RH(2). A resistance ratio bridge with a cryogenic current comparator (CCC) is used for the measurements. The typical relative standard uncertainty in measuring a 1 Ω resistor is estimated to be about 4 × 10-9. The resistance standard maintained at the National Institute of Metrology (NIM, China) is based on the average value of six wire-wound 1 Ω resistors. It was monitored using the ETL quantum Hall effect (QHE) resistance standard in 1992, 1996 and 2000 by bringing 1 Ω resistors from the NIM to the ETL or from the ETL to the NIM. The drift rate of the standard was measured to be -0.024 µΩ/year. The NIM has developed a CCC bridge. The typical relative standard uncertainty in measuring a 1 Ω resistor using this CCC bridge and the QHE system of the NIM is estimated to be about 7 × 10-9. The NIM QHE system was compared with the ETL QHE resistance standard by bringing three 1 Ω resistors from the ETL to the NIM. Differences in the measurements were (+3.9 ± 8.9) nΩ, (+1.0 ± 9.9) nΩ and (-0.9 ± 9.1) nΩ, respectively.
73.43.Fj Novel experimental methods; measurements
84.30.Qi Modulators and demodulators; discriminators, comparators, mixers, limiters, and compressors
07.20.Mc Cryogenics; refrigerators, low-temperature equipment
Issue 2 (April 2002)
M Nakanishi et al 2002 Metrologia 39 207
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