NIST Broadens Collaboration with BIPM to Enhance Voltage Standards

The National Institute of Standards and Technology (NIST) has expanded its comparison program with the Bureau International des Poids et Mesures (BIPM) and the South Korea Metrology Institute (KRISS) to enhance the precision and reliability of electrical measurements globally. This collaboration focuses on Josephson voltage standards, which produce quantum-based voltages used for calibrating many instruments. 

Staff from BIPM visited the NIST Boulder laboratories to compare the BIPM transportable Programmable Josephson Voltage Standard (PJVS) with the NIST Josephson Arbitrary Waveforms Synthesizer (JAWS). The JAWS is a primary standard that produces high-purity periodic signals in the hertz to megahertz range up to 2 V. The BIPM PJVS was tested in various configurations using the stable and reproducible signals produced by the NIST JAWS. This testing pushed the reliability of the BIPM PJVS to its limits and achieved a Type A uncertainty of a few parts in 10^9 for a 10 Hz sinewave at 2 V rms. The protocol for this new BIPM comparison was established by a group of CCEM experts and released in June 2023. This pilot study was the last verification of the protocol before the start of official AC voltage measurements. 21 NMIs expressed interest in participating in the coming years, with 16 interested in AC measurements. 

Based on the Josephson effect discovered in 1962, the Josephson voltage standards have revolutionized how nations calibrate their measurement systems for voltage, ensuring consistency and reliability across global industries. This technology plays a crucial role in various applications, from the calibration of test and measurement equipment to the development of cutting-edge electronics and precision engineering. 

The expanded program between NIST and BIPM aims to combine expertise, enhance measurement reliability, and further harmonize the Josephson voltage standards, facilitating a more seamless international framework for electrical measurements. By comparing and validating their respective standards, the two organizations endeavor to eliminate discrepancies and foster a unified approach to measurement accuracy using quantum-based voltage standards. 

The Bureau International des Poids et Mesures, headquartered in Sèvres, France, is an international organization that works with member states to promote and maintain global uniformity in measurements. Its partnership with NIST underscores a shared commitment to upholding the highest metrological standards. 

As the program progresses, NIST and BIPM will continue sharing insights and findings with the international metrology community, reinforcing the global scientific and industrial measurement network.