[volt-nuts] DIY JJ was Re: HP 3458A

[Marvin E. Gozum]

I too.  But to raise a skeptics eye, the fundamentals of design is 
one of material chemistry and requires a different skill set.

 From NIST papers, a JJ would require IC style fabrication, in order 
to get the sandwich of super and nonsuperconducting material to the 
right dimensions.  Building a simple transistor would be an exercise 
for the JJ, and since Lilienfeld's FET, from 1925 to Shockley in 
1949, DIY transistors have only recently been attempted and if 
successful, are far inferior in capability than any 20c 2n2222 you 
can get at Radio Shack.  It suggests to me the success rate of 
getting high tolerance layers are fairly slim.

http://en.wikipedia.org/wiki/Josephson_Effect

Looking even at the venerable work at time nuts, folks maintain 
purchase standards, not hand build from raw materials, then most of 
the discussion is product maintenance and calibration.

At volt nuts, most of the discussions of DIY volt center around 
purchasing and maintaining surplus Fluke standards or similar zener 
or band gap style reference, and maintaining them too.

This suggests that a volt nuts JJ would likely be when someone 
produces a JJ in a box that, like a Cs or Rb clock, still requires 
substantial upkeep and maintenance just as the surplus clocks are 
maintained by the time nutters, or Fluke standards maintained here.

http://www.wired.com/science/discoveries/multimedia/2007/12/gallery_time_hackers?slide=9&slideView=10


A realistic possibility is awaiting when salvaged 'high temperature' 
N2 cooled SQUID devices are available and design a JJ around it.


At 07:06 PM 8/8/2011, Chuck Harris wrote:
>Volt-nuts is to voltage measurement and standards as time-nuts is to
>time measurement and standards.  It should include everyone with an
>interest in maintaining voltage (current/resistance) standards.
>
>I, for one, would like to learn about making JJ voltage standards in
>a volt-nut setting.
>
>-Chuck Harris



Sincerely,



Marv Gozum
Philadelphia, PA