Comparison of resistance standards between the National Institute of Metrology (China) and the Electrotechnical Laboratory (Japan)

摘要

The resistance standard maintained at the Electrotechnical Laboratory (ETL, Japan) is based on the resistance of the second plateau of the quantized Hall resistance, R_(H)(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.