[time-nuts] MIT 2 inch cesium fountain, optically pumped
Jim Lux
jimlux at earthlink.net
Thu Nov 20 07:40:37 EST 2014
On 11/19/14, 9:17 PM, Magnus Danielson wrote:
> Hi Rick,
>
> They did not mention the complexity of the laser system they needed,
> especially considering that the optical bench of a fountain isn't all
> that small, and also because they want to de-tune lasers. While they
> seems to have an idea, they didn't touch on that subject.
>
> Nice to see that people think in a different way thought.
>
> Looking forward to see the progress on this one.
>
> Cheers,
> Magnus
>
> On 11/20/2014 05:24 AM, Richard (Rick) Karlquist wrote:
>> See:
>>
>> http://newsoffice.mit.edu/2014/portable-atomic-clocks-1112
>>
>> Any comments?
>>
And, of course, the article being cited in the news release is behind a
paywall..
I'm always a bit cynical when I see the words like
"We have a path toward making a compact, robust clock that’s better than
CSACs by a couple of orders of magnitude, and more stable over longer
periods of time.”"
and "potentially the size of a Rubik’s cube."
That "path towards"....
Having watched the progress of the SpaceClock/1 Liter Atomic Clock/Deep
Space Atomic Clock (all names for the Hg ion clock).. it's a long long
way from "concept sort of demonstrated in the lab" to "device I can buy
with a large-ish check"
Just reading the abstract, which doesn't give much detail about how "lab
bench" this is, I'm going to guess this is at TRL 3 - basic principle
demonstrated on a lab bench.
The press release is talking about applications at TRL 8 or 9. A
finished product..
It's probably 20-30 years away, and getting from lab full of equipment
to "Rubik's Cube" (i.e. a liter) is going to be a lot more challenging
than those authors think, I suspect.
That said, it's neat to see folks pushing in different directions.
The other day I was down in a lab under my office and saw a "breadbox
sized" unit that can cool some atoms down to 100 picoKelvins in a few
seconds with the push of a button.
http://coldatomlab.jpl.nasa.gov/
And not too long ago(1995), that was lab full of gear and a team of
researchers struggling for days to get it to sometimes, maybe work.
http://jilawww.colorado.edu/bec/BEC_for_everyone/
"The current experimental systems were designed by people with a
tremendous amount of knowledge and experience in experimental atomic
physics, and until now producing a BEC without expertise in ultracold
atom trapping has been a daunting task" from
http://jilawww.colorado.edu/bec/CornellGroup/JLTP_Lewandowski2003.pdf
so, from
first demo in a lab in 1995 - which got them a Nobel
to cookbook for grad students and post docs and $300k in 2003
to one-off box that has a pushbutton and fits in a locker on ISS in 2015
http://coldatomlab.jpl.nasa.gov/news/CalTest/ has a picture of the box
on the shaker table
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