[time-nuts] Used Hydrogen Maser

[Michael Wouters]

about 20 years ago, JPL was operating a Hg ion clock at the  Tidbinbilla
tracking station just outside Canberra, Australia. I think they installed a
few at various nodes in the Deep Space Network at the time. It operated for
a few years but never reliably enough to be a useful UTC clock ( we were
submitting the data to BIPM). I don’t know what happened to it.

Cheers
Michael

On Thu, 11 Jul 2019 at 3:01 am, jimlux <jimlux at earthlink.net> wrote:

> On 7/10/19 6:10 AM, Azelio Boriani wrote:
> > Tom Van Baak said on Aug 29, 2013:
> >
> >> The pursuit of precision tends to be exponential rather than linear.
> > ...
> >> As a rough example in the ADEV world:
> >> - for 1e-11, you can buy almost any XO, TCXO, or risky OCXO for $10.
> >> - for 1e-12, you can find a reputable OCXO on eBay for under $100.
> >> - for 1e-13, you can find an old but maybe working cesium clock for 1
> k$.
> >> - for 1e-14, spend 10 k$ and get a certified working hp 5071A.
> >> - for 1e-15, spend 100 k$ and find a used active H-maser.
> >> - for 1e-16, spend 1 M$ to hire physicists and build a Cs fountain.
> >> - for 1e-17, spend 10 M$ to fund a national research institute to build
> ion or
> >> optical clocks.
> >
> >
> > Add the 1k USD running cost per year just to keep the active maser
> running.
> > I think that chances of finding an active H-maser used are near 0.
> > Better to stick with GPSDOs: they bring into your home the stability
> > and accuracy of the USNO UTC (well, close to...).
> >
>
>
> I wonder what it would cost to build a trapped Hg ion clock - I don't
> think it's $10M, but it might be in the range of $500k-1M if you pay
> people to do the work.  Things like the quadrupole trap and ion sources
> are catalog items.  The whole vacuum system, including a turbo pump, is
> probably in the $10k range (looking at the Cole Parmer catalog, first
> hit on google), maybe another $5k in various vacuum plumbing bits and
> pieces.
>
> back in 2005-2006 (published in 2007), Prestage et al had a lab version
> https://ieeexplore.ieee.org/document/4319251
>
> pumped, backfilled with Ne, then sealed
>
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