[time-nuts] Is the lifetime of a Rb standard dependent on operating orientations/

[Richard (Rick) Karlquist]

Surface tension keeps the liquid Rb in place in the short term.
In the long term, the Rb has to be designed to have place
where the Rb was concentrated to be at the lowest temperature.
In the HP10816, this place was the "tip-off" for the cell.
We tried to heat sink the tip-off to cool it off.  The big
problem would be if Rb condensed on the cell and blocked
some of the light, causing a frequency error.

Another issue was the "flooded cell" vs the "starved cell".
There is no liquid Rb in the starved cell.  In 2020 hindsight,
we really didn't know what we were doing, and the 5065 designers
were no longer around to coach us.

Rick

On 7/23/2019 7:45 AM, Dana Whitlow wrote:
> It seems to me that the basic operation of the Rb cell and/or the filter
> cell
> and lamp must all involve the presence of some liquid Rb at normal
> operating temperatures.  Otherwise, temperature regulation would not
> be a viable means of controlling the Rb concentration on the vapor mix.
> 
> If I'm right about this, is there a concern that operating the device in an
> inappropriate orientation might lead to liquid "puddling" in some area
> that is harmful to either operating stability or operating lifetime?
> 
> Or is it that the amount is so small (~100 ug according to what I've
> read) that it just doesn't matter?
> 
> Thanks,
> 
> Dana    K8YUM
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
> 
>