[time-nuts] quartz / liquid nitrogen

Dana Whitlow k8yumdoober at gmail.com
Mon Apr 2 16:30:39 EDT 2018

Is the thermal noise generated in the loss in a quartz resonator a
significant part
of the overall phase noise picture?  I would have not thought so.  I'd
think that a
greater benefit ought to be derived from chilling the other parts in the
such as the active devices.  Unless, of course, chilling the quartz
actually improves
the Q significantly, which I don't know about.

If cooling (whatever) by just a modest amount helps much, then one could
consider using Peltier cooling.  It doesn't really get things very cold,
but is a
lot more convenient than either dry ice or LN2.  But then you don't get the
that you do when playing with LN2, either.


On Mon, Apr 2, 2018 at 2:46 PM, Tom Van Baak <tvb at leapsecond.com> wrote:

> 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. Would that dramatically lower
> temperature improve phase noise & short-term performance? Is there a
> crystal cut that could be optimized for 77 K instead of ~25 C (room) or 60
> C (oven)?
> If not Nitrogen, how about dry ice (-109F -78C)?
> /tvb
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