[time-nuts] Confused about Rubidium oscillators
John Ackermann N8UR
jra at febo.com
Wed Nov 14 17:03:01 UTC 2012
From what's been reported here, the mechanism isn't consumption of the
Rb, but rather deposition of material on inside of the bulb, reducing
its intensity, and that can sometimes be reversed by tricks that some
time-nuts have reported -- it's more of a maintenance rather than a
wear-out issue.
I think that's quite different from a Cesium tube, where the cesium is
actually depleted as it is ionized and sent down the beam.
Otherwise, there are failure modes that result from components running
at elevated temperatures for many years. I'd also consider those
maintenance.
John
----
On 11/14/2012 11:56 AM, Bob Smither wrote:
> Do Rb oscillators wear out? I have found:
>
> "There are no “wear-out” or “use-up” mechanisms in a Datum
> Efratom Rubidium oscillator."
> -- Datum - Note About Rubidium Oscillators
>
> and
>
> "Atomic Vapor Oscillators have no wear out mechanism."
> -- FEI - Precison Oscillator Overview, 2007, p19.
>
> But also:
>
> "Unlike a quartz crystal oscillator which has no clearly-defined "wear out"
> period and, if well-designed, can actually improve as time goes on, a Rubidium
> reference has a definite lifetime associated with its lamp: As the unit
> operates, the Rubidium within the lamp is gradually consumed and eventually, too
> little vapor is available for the atomic resonance to be detected and the unit
> fails."
> -- http://www.ka7oei.com/10meg_rubidium1.html
>
> and
>
> The page at:
> http://www.oscilent.com/esupport/TechSupport/ReviewPapers/IntroQuartz/vigcomp.htm
> also mentions a wear out mechanism.
>
> and
>
> "These OCXOs maintain performance characteristics comparable to Rubidium
> oscillators without their high cost and inherent wear out,"
> --
> http://www.microwavejournal.com/articles/2301-an-ocxo-with-rubidium-oscillator-performance
>
> Finally I found:
>
> "Problems with rubidium cell wear-out have been solved and manufacturers now
> offer essentially unlimited warranties against cell failure."
> --http://www.endruntechnologies.com/frequency-standard-oscillators.htm
>
> so maybe both points of view are correct?
>
> I recall seeing something about rejuvenating Rb oscillators on this list, so I
> suspect Clint is correct.
>
> Whose right? As a time-nut, do you leave your Rb oscillators on 24/7?
>
> Thanks,
>
>
>
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