NIST Delivers Advanced Quantum Voltage Standard to BIPM
NIST has delivered a state-of-the-art Programmable Josephson Voltage Standard (PJVS) to the International Bureau of Weights and Measures (BIPM) in Paris. This compact, portable system will serve as BIPM’s primary transfer standard for voltage comparisons with national metrology institutes worldwide.
The new PJVS, developed by NIST’s Quantum Electronics and Photonics Division, offers improved ease of use and measurement capabilities while maintaining the lowest uncertainties currently achievable. It represents the first traveling PJVS system designed with compact electronics for easy transportation between countries’ national measurement laboratories.
The system was constructed and tested at NIST’s Boulder labs, where it was found to agree with a second PJVS system to within 2.6 parts in 10^11, with a total combined uncertainty of 3.4 parts in 10^11. This is the smallest combined uncertainty achieved to date when comparing two PJVS systems.
The PJVS technology is based on the Josephson effect, a phenomenon discovered by Welsh physicist Brian Josephson in 1962. This effect exhibits an invariable, quantized relationship between voltage and current across a Josephson junction between two superconductors. The first Josephson voltage standard systems were able to calibrate single dc voltages, while the newer PJVS systems can be rapidly programmed to produce any direct current (DC) voltage between +10V and -10V, allowing them to calibrate sine waves with frequencies up to 500 Hz.
The BIPM system, optimized for traveling, includes a lightweight synthesizer and advanced filtering that improves performance and protects the chip from electrical discharges. It will be used to conduct comparisons with other national metrology institutes in the coming years.
Source: https://www.nist.gov/news-events/news/2013/10/quantum-voltage-standard-delivered-bipm
Keywords: Josephson, Metrology, Superconductors, Voltages, Standardization
