[time-nuts] Crystal Ageing

Rick Karlquist richard at karlquist.com
Tue Oct 9 20:20:13 EDT 2007

I was the person who posted the original comments.  My comments
were based on discussions with notable crystal guru, Jack Kusters,
who was merely an inventor of the SC cut.  He didn't have much
confidence in the various FCS papers Jeffrey was referring to.
Basically, he was aware of all those effects and if there were
any consistency to the proposed treatments, the HP crystal fab
would have been doing them.  For instance, the idea that, if
only you polish the crystal well enough, it won't age has been
debunked.  Some people currently making high quality crystals
learned much of what they are doing from Jack in the first place.
If any of them go beyond what Jack taught them, they might
publish at FCS.  Or they might not and keep it as a trade secret.

Rick Karlquist

(these are my personal opinions, and do not represent the official
position of Jack or HP.).

effrey Pawlan wrote:
> ); SAEximRunCond expanded to false
> Errors-To: time-nuts-bounces+richard=karlquist.com at febo.com RETRY
> It was Rick who wrote about crystal aging. It is not predictable whether
> the
> crystal will go higher or go lower in frequency and there is no guarantee
> that
> it will age at a linear rate. The worst-case is when a crystal erratically
> jumps.
> I had attended a conference of the Frequency Control Symposium of the IEEE
> in
> which the causes were discussed. There was disagreement among the experts.
> Some
> thought it was owing to the physical stress or surface imperfections
> caused by
> grinding and lapping. Others thought it may be partially a result of the
> etching. Others thought it was caused by microscopic impurities in the
> quartz.
> Others talked about the effects of plating. Rick wrote about the
> microcrystalline structural defects. Perhaps all of these contribute and
> it is
> unpredictable how they will add together.
> 73,
> Jeffrey Pawlan  WA6KBL
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