[time-nuts] 12.6GhZ Yb clock - was Cs tube pics

Bob Stewart bob at evoria.net
Wed Nov 2 16:54:42 EDT 2016

Hi Michael,
I've got a dumb question about the need for a really good flywheel oscillator for the 12.6Ghz Yb clock:  What is the signal that is locking that oscillator?  Is it a 1PPS, or is it something in the RF domain, such as 10MHz or higher?
I still hope to make a modern version of the old water-hydrogen generator from the 40s or whatever it was.  But, my copious free time seems to be taken up now that I have the time to do it.

Bob - AE6RV -----------------------------------------------------------------


      From: Michael Wouters <michaeljwouters at gmail.com>
 To: Discussion of precise time and frequency measurement <time-nuts at febo.com> 
 Sent: Wednesday, November 2, 2016 3:42 PM
 Subject: Re: [time-nuts] Cs tube pics
I worked on a trapped ion frequency standard 20 years ago, a 12.6Ghz Yb
clock. It's still in the lab across from me and looking at it, and the
electronics, I think it is the sort of thing that a physicist might
contemplate building in his/her garage but ...

Building it took about 10 man years of concentrated effort so the time you
would need for a project like this would be the killer, assuming you could
buy the spectroscopic lasers and UHV equipment you needed at a price that
didn't require refinancing your mortgage.

One other vital component is the flywheel oscillator you need to take
advantage of the fabulous stability you now have at hand.We had a cryogenic
sapphire oscillator for our (microwave) clock.

For an optical clock, you're also going to need a frequency comb to get
back into the RF domain.



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