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Performance of a Cryocooled Nb DC Programmable Voltage Standard at 4 K

Published

Author(s)

Robert J. Webber, Charles J. Burroughs, Masoud Radparvar

Abstract

We report on the performance of a 1 Volt DC programmable Josephson voltage standard (PJVS) operating on a commercially available Gifford-McMahon (G-M) cryocooler at 4 K. The NIST-fabricated niobium superconductor-normal metal-superconductor (SNS) junction chip has been shown to operate successfully as integrated with this cryopackage, generating 1.229 V at the maximum operating frequency of 19.364 GHz with Shapiro steps at constant voltage which are flat to within <100nV. Because of the large operating margin (>1mA), these steps were highly stable and immune from noise. Differences in behavior of the PJVS in liquid helium (LHe) and on the cryocooler are discussed. This demonstration paves the way towards automated warming and cooling of the Josephson device and a fully automated voltage standard system.
Citation
IEEE Transactions on Applied Superconductivity
Volume
17
Issue
4

Keywords

cryocooler, dc voltage, Josephson voltage standard, SNS Josephson junctions

Citation

Webber, R. , Burroughs, C. and Radparvar, M. (2007), Performance of a Cryocooled Nb DC Programmable Voltage Standard at 4 K, IEEE Transactions on Applied Superconductivity (Accessed July 23, 2024)

Issues

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Created December 2, 2007, Updated October 12, 2021