Jim
I am sorry to say thats the wrong clock picture.
That picture is of 2 glass coffee tables and a toaster in between.
I see you can order that art om ebay. Item number 142657nottoday3245
Regards
Paul
WB8TSL

On Fri, Oct 31, 2014 at 1:36 PM, Jim Lux jimlux@earthlink.net wrote:

Hi

Either my mag coil “do it in your head” math is off or that’s a pretty low field Helmholtz setup. Skinny coils….

Bob

Humor aside. I did dig deeper. It seems that this technology could be
commercialized in larger volumes and might land in the same cost as a good
CS does today. Technically it looks reasonable.
Regards
Paul
WB8TSL

On Fri, Oct 31, 2014 at 1:45 PM, paul swed paulswedb@gmail.com wrote:

On 10/31/14, 5:05 PM, Bob Camp wrote:

Just to cancel earth's field or to simulate maybe Jovian fields.

Or, just to evaluate the sensitivity.

And, of course, it's all about Ampere Turns.. Maybe those are special
room temperature superconducting coils carrying kiloamperes?

We could always send an email to Bob and ask him..

Hi

Trapped ion clocks have been the “obvious successor” to a Cs tube for at least 30 years. There is a lot of very fancy work involved in getting from 10 MHz up to a very specific light wavelength with low ADEV and good phase noise…..

Rocket science indeed. Time Nuts rocket science, but tough to do none the less.

Bob

Hi

….. or the test only needs to run for a very short time…..

I guess I’ll have to ask Mr Wikipedia what Jupiter’s mag field looks like …

Bob

Hi Bob:

I suspect that inside a screen room like that one, where I'm guessing the walls are iron/steel, there's not much of the
Earth's mag field left to null.
Mail_Attachment --
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Bob Camp wrote:

Some papers by Todd Ely, PI for DSAC..
3E-15 at tau of 86,400 seconds

https://www.researchgate.net/publication/260036335_Expected_Performance_of_the_Deep_Space_Atomic_Clock_Mission

http://trs-new.jpl.nasa.gov/dspace/handle/2014/43016

On 10/31/14, 10:36 AM, Jim Lux wrote:

In message 54544287.3000805@pacific.net, Brooke Clarke writes:

That would be very counter productive, because you would invariably
get a very complex mag field which owuld be much harder to cancel out.

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG        | TCP/IP since RFC 956
FreeBSD committer      | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

Hi Bob,

The traditional Hg ion clock with it's 40,5 GHz frequency is doable, but
it would be interesting if it could be commercialized at a (time-nuts)
friendly price.

The modern optical clock got much easier to work with when the frequency
comb was invented. The frequency comb and stable lasers is now
commercialized, but not cheap, not cheap at all.

Cheers,
Magnus

On 11/01/2014 02:27 AM, Bob Camp wrote:

Magnus,
But for a time-nut how can price even enter into the conversation? Plus it
only draws 10s of watts. A green super duper clock. Other comment I read is
that there is no part that will wear out. Granted I suspect over many years
something happens, but its not the typical CS depletion. I might speculate
the glass windows fog or something or on earth the evacuated chamber
ultimately leaks or the metal in the vacuum release stuff.
No idea but pretty sure I won't be putting a watch on ebay any time soon.
Regards
Paul
WB8TSL

On Sat, Nov 1, 2014 at 6:42 AM, Magnus Danielson <magnus@rubidium.dyndns.org

Paul,

You mean, as all time-nuts already have redundant sites with at least 4
5071As with high-performance tubes, redundant cesium and rubidium
fointains, set of active hydrogen masers, with everything in tight
temperature, humidity and pressure control, UPS and diesel-engines,
GPS/GLONASS/GALILEO receiver on temperature-stabilized piller and
antenna, do TWSTFT to major labs... since money is no issue, right?

The main problem with cesium tubes as I recall it is really the ionizer
in the mass-spectrometer being poluted with cesium, this then creates
bad S/N before running out of cesium in the oven.

Yes, I agree it would be a great clock to have, but practical limits in
cost is a challenge for most, so it would be interesting to look at it
and ask how cheap it could be done.

Cheers,
Magnus

On 11/01/2014 03:21 PM, paul swed wrote:

Absolutely! but it's not just the price of the hardware. The clock has mercury
in it. Horrors! So the paperwork involved with the EPA, OSHA, and who knows
what other agency will cost more than the hardware. Best stick with a hydrogen
clock, just stick an icepick in it when you want to get rid of it; pfffft and
it's done. Safer than your old refrigerator. :-)

seriously, tn's, see:
http://www.microsemi.com/document-portal/doc_view/133441-rubidium-devices-material-safety-data-sheet

Don

paul swed

--
"The power of accurate observation is commonly called cynicism by those who
have not got it."
-George Bernard Shaw

Dr. Don Latham AJ7LL
Six Mile Systems LLC
17850 Six Mile Road
Huson, MT, 59846
mail:  POBox 404
Frenchtown MT 59834-0404
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Skype: buffler2
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www.sixmilesystems.com

On 11/1/14, 9:08 AM, Magnus Danielson wrote:

Having been to a few of the design reviews and such for the DSAC, and
before, when it was called the 1 liter atomic clock, etc.

I think one could build one if you have a fairly wide collection of
skills, and you weren't hung up on it being tiny and low power, and zero
maintenance.

For instance, building a perfectly sealed physics package that is space
flight compatible is non-trivial. Most of us don't have e-beam welding
equipment sitting around (nor does JPL.. we contract that kind of stuff
out).  As Prestage points out in the article below, they started looking
at how they build long life Traveling Wave Tubes for space (another
precision ion optics device), and having spent some time in various TWT
factories over the past 15 years: there is a lot of art in the
manufacturing process.

http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/41329/1/07-2003.pdf
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/41395/1/08-0610.pdf

However, if you were happy with "lab grade" construction, and you have
the Kurt Lesker and Duniway catalogs as bedside reading, I think you'd
have a chance.

The ion trap and such is a fairly straightforward thing, from what I
understand: you need the usual vacuum pumps and such to build one.  If
you don't want it to run for years without servicing, then issues of the
mercury content are less important.
(BTW, the space clock uses thermal dissociation of HgO to get the mercury)

The PMT is an off the shelf thing. Check out the amateur built fusion
reactor (fusor) websites on where to get PMTs and amplifiers (they're
used behind a scintillator)

The 40 GHz stuff these days is not nearly as exotic as it used to be.
The challenge might be test equipment when you're debugging your 40 GHz
synthesis chain.

I don't think it would be easy, but I think doable, and nothing in the
system is particularly expensive or that exotic.  It's sort of like
telescope building.. The raw materials to make a 18" reflector telescope
aren't all that expensive, nor is there some secret sauce: it's just
time to grind the mirror (and recover from mistakes) and build the system.

Magnus I would say that yes I do have various backups and none as good as
any of this discussion. Agreeing with Jim much of this appears to me to be
semi-reasonable and in particular in a amateur lab environment. But I am
afraid thats just about how far I am going to get on the project. Its right
behind the H maser. Any day now. Recovering the Frankenstein CS was about
my real limit. I haven't seen any tubes show up on ebay lately. :-) Such is
life.
Regards
Paul
WB8TSL

On Sat, Nov 1, 2014 at 12:49 PM, Jim Lux jimlux@earthlink.net wrote:

Jim,

On 11/01/2014 05:49 PM, Jim Lux wrote:

Ah, yes, most time-nuts is not aiming to shoot their clocks into deep
space. We are satisfied to stay in geostationary orbit or lower ;-)

Yes. I guess a bit of baking out the build is also to be recommended.
I guess most of us don't do vacuum in our labs, so there is a challenge
in itself, as there is many beginners mistakes to be done there.

Have tou cared to get the right isotope or do you use the natural
abundance spreading? Hg-199 has an abundance of 16,87%.

Ah yes. Got a NaI(Tl) scintilator with about 1 cm copper filter and a
matching PMT. No amp thought, but then again, I do not know what I
should measure with it. :)

I was thinking the same, especially when consider optical clocks, then
40 GHz isn't as esoteric. Traditional cesiums and rubidiums use a pair
of synthesized frequencies being then sent into a step-recover diode
inside a tuned cavity which then does the mixing and selects the right
combination.

Would be a fun project to do, things to be learned.

Cheers,
Magnus

Paul,

The lack of hydrogen masers here is disturbing. So is better cesiums
tanked up and fresh.

Will see what I can do with what I got.

Fixing up rubidiums and cesiums is currently how far this lab goes.

Cheers,
Magnus

On 11/01/2014 06:23 PM, paul swed wrote:

On 11/1/14, 11:05 AM, Magnus Danielson wrote:

I haven't done high vacuum in quite a few years, but it is fascinating
and frustrating. These days, quite a bit of surplus gear is out there
that does make life easier (e.g. turbo molecular pumps).  A Hg Ion
system isn't real huge, and doesn't have a big gas load, so a
straightforward LN2 sorption pump would probably work as a batch
mode(e.g. a bunch of the right material, plunged into a LN bath, and it
the gas molecules just stick right to the material.. )

Interesting, I don't know if they go out and sort it, or if they set up
the system so that it's basically a mass spec, and the wrong isotope
doesn't make it through the quadrupole filter.  I'll bet the latter. No
matter how good your offline enrichment process is, there will always be
some other "stuff" in there.  For all I know, the actual ion trap is
specific to the mass of the ions.

You can measure radiation from common household objects like bananas

Same scheme might work here. Next time I'm talking to one of the DSAC
folks, I'll ask how they do the synthesis chain.

For when you get tired of counting femtoseconds..

Hi

Don’t in any way discount the amount of effort in getting that filter to work “right”.

Can you get this all done with 40 GHz as your “top” frequency?

Then you need to build a second one to check the first one with.

Bob