[volt-nuts] DIY JJ was Re: HP 3458A
cfharris at erols.com
Tue Aug 9 13:07:47 UTC 2011
It is the conversation about JJ's that I wanted to stimulate. I think
each and every one of us would like to have a JJ standard to feed and
nurture, just like the time-nuts all want C-beams, or H-masers.
Standard cells are nice, but just not very satisfying, being stable,
but always wrong in ways we cannot predict. Without access to a real
standards lab, we simply cannot find anything resembling a standard
volt from our standard cells.
Today, a bog ordinary EE student, at any engineering college, can get
just about any chip he wants made using the facilities of this-or-that
fab, using the MOSIS, and other interchange standards. If we knew
enough about what we needed in our JJ array, could we too get them made
for a not too painful price?
And remember, the first guy that did this most probably relied more on
his tenacity in building the JJ than he did in the fab finesse of an
intel, or motorola.
I truly like the idea of an optically pumped peltier stabilized JJ.
With something like that, we could at least calculate how the
voltage we have created relates to the JJ that defines the volt.
Poul-Henning Kamp wrote:
> In message<184.108.40.206.2.20110809070749.04f33918 at jefferson.edu>, "Marvin E. Gozum"
>> 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.
> The one thing I have never sat down and tried to calculate, is if
> there is any reason in a high-temp superconductor JJ standard or
> if the increase in thermal noise will make it a pointless exercise.
> The reason I wonder is that the present standards have a very low
> per "cell" voltage and therefore operates with thousands of cells
> in series to get to 10V.
> One way to counter that, would be to increase the stimulation
> frequency from the current ~75GHz into the optical regime, since
> (at least as far as I understand it) the voltage per cell is
> proprotional with the stimulation frequency.
> Then it starts to get interesting: A frequency stabilized semiconductor
> laser (like in the CSAC) hitting a peltier-stabilized super-conductor.
> If that is even possible, it would be considerably more amateur
> friendly than liquid Helium and 75GHz waveguides.
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