Publication Citation (NIST authors in bold)
Authors:	Tang, Y. , Miller, W. B., Pardo, L. P.
Title:	A Direct Josephson Voltage Standard Comparison between NIST and Lockheed Martin Mission Services for Supporting NCSLI Intercomparison
Published:	September 01, 2009
Abstract:	To support the 8th JVS Interlaboratory Comparison (ILC) in 2008, sponsored by the National Conference of Standard Laboratories International (NCSLI), a direct Josephson Voltage Standard (JVS) comparison using the NIST compact JVS (CJVS) was carried out in March 2008 between NIST and Lockheed Martin Mission Services (LMMS). LMMS is the pilot laboratory for the JVS ILC 2008. A comparison between NIST and LMMS will provide all of the JVS ILC participating laboratories with a link to NIST. A protocol designed for the JVS direct comparison is described in the paper. It is possible to use a direct JVS comparison to detect JVS system errors associated with the frequency measurement, cryoprobe leakage correction and the Josephson junction array. These errors are small in magnitude and are not normally detectable by other types of JVS comparisons, such as the Zener Measurement Assurance Program (MAP). The difference between the LMMS JVS and the NIST CJVS at 10 V was found to be 0.71 nV with an expanded uncertainty of 6.87 nV (k = 2) or a relative uncertainty of 6.87 parts in 1010, which is a factor of 4 improvement compared to that of the in situ indirect JVS comparisons implemented in the NCSLI JVS ILC 2005 and a factor of about 40 improvement compared to the results from the NCSLI JVS ILC 2002. This comparison has verified the LMMS JVS and also has confirmed that LMMS is well prepared to serve as the pivot lab for the NCSLI JVS ILC 2008.
Citation:	Measure: The Journal of Measurement Science
Volume:	4
Issue:	3
Pages:	pp. 28-32
Keywords:	Compact Josephson voltage standard (CJVS), direct JVS comparison, interlaboratory comparison (ILC), uncertainty
Research Area:	Standards, Quantum Electrical Measurements;
PDF version:	Click here to retrieve PDF version of paper (221 K)