[volt-nuts] What made a HP3458A so expensive

[Mark Sims]

Some Russian company has a JJ standard that uses high-temp superconductors and liquid nitrogen cooling.  Because of things like grain boundary issues in the HTS,  it is not quite as good as a 4K cooled unit.
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Of course at the
present time given the fact that the JJ has to be cooled to below 4.2 K
makes this idea more than a little impractical