[time-nuts] quartz / liquid nitrogen

[Poul-Henning Kamp]

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In message <299B45118C9248498D7B4F3AFE72231E at pc52>, "Tom Van Baak" writes:

>Has anyone tried running a quartz oscillator at liquid nitrogen
>temperatures: -196 C (-321F, 77K)? It's probably impractical
>commercially, but maybe something of value to a time nut.

Whispering gallery sapphire resonators at cryogenic temperatures
is a thing for phase-noise, but those are dielectric (microwave)
resonators, not piezoelectric resonators.

> Would that dramatically lower temperature improve phase noise &
> short-term performance?

Yes it will reduce your thermal noise as a source of PN, and
dramatically so.

But I doubt short and long term performance will improve.

Even if you can find a zero-turnover cut at a convenient temperature,
I don't think anybody know how to produce mK temperature *stability*
at cryogenic temperatures ?

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