Re: [time-nuts] Team of physicists repeats tvb Project GREAT

[Bob kb8tq]

Hi

> On Feb 15, 2018, at 9:03 AM, jimlux  wrote:
> 
> On 2/14/18 6:51 PM, Tim Lister wrote:
>> On Feb 14, 2018 19:47, "Chris Caudle"  wrote:
>> On Wed, February 14, 2018 7:06 pm, jimlux wrote:
>>> At substantially more expense, and with an experimental lattice clock,
>> Does that schematic figure in the paper imply that the "transportable"
>> strontium and ytterbium clocks are built into trailers instead of the
>> traditional rack enclosure?
>> Actually now that I look more closely it looks like maybe two trailers.
>> Doesn't seem like something that Jim is going to be flying any time soon.
>> Yes. From the Nature article text:
>> "The transportable 87Sr lattice clock is (compared with laboratory clocks)
>> designed to be compact, with robust optical parts12
>> . The physics
>> package is less than 0.6 m3 in size, and we use laser breadboards with
>> mechanical stress-resistant fibre couplers21
>> . All
>> components except the reference cavity of the interrogation laser are
>> rigidly mounted in a car trailer (size 2.2 m × 3 m × 2.2 m), and vibration
>> isolation is provided by rubber dampers. The trailer interior is
>> temperature stabilized, while the small volume of the trailer hinders air
>> exchange and generates hot spots with more than 10 K temperature rise.
>> However, the optics and the physics package are placed apart and shielded
>> from these and are stable to within 0.4 K after an initial temperature rise
>> of about 1 K. The transportable ultrastable reference cavity for the clock
>> interrogation lasers is rigidly mounted to endure transport12
>> . It was placed
>> next to the trailer to avoid its performance being degraded by vibrations
>> induced in the trailer’s air conditioning system. The vibration amplitudes
>> in the trailer are a factor of ten larger than under typical laboratory
>> conditions, leading to a corresponding increase in clock instability. A
>> reference resonator with lower acceleration sensitivity or an active
>> feed-forward system may in the future remedy this inconvenience22
>> ."
> 
> 
> We have discussed the desirability of suitable caves for operation of high 
> quality clocks many times on this list.
> Clearly this is another instance.

Search the archives for “swimming pool full of mercury” for one go around on 
this.

Bob



> 
> With respect to flying such things in space - this is the continual challenge 
> - DSAC (the trapped mercury ion clock) was a couple of benches in a special 
> time keeping lab when I first saw it, oh, a decade ago?. It will fly later 
> this year and it's probably about the size of an airplane carry-on.
> https://www.jpl.nasa.gov/missions/deep-space-atomic-clock-dsac/
> 
> Cold Atom Laboratory basically takes several optical benches operated by a 
> team of post-docs that makes Bose Einstein Condensates (BEC) and turns it 
> into a box the size of a dorm refrigerator that goes "ping" when you press a 
> button and makes a BEC (in either Rb or K, as you choose).
> 
> https://coldatomlab.jpl.nasa.gov/mission/
> 
> Just as a rule of thumb, I've found that it takes about 10-20 times the cost 
> to get from "benchtop prototype"(TRL 5) to "flyable unit" (TRL 6), as it cost 
> to get from idea to benchtop prototype.
> 
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Re: [time-nuts] Team of physicists repeats tvb Project GREAT

[jimlux]

On 2/14/18 6:51 PM, Tim Lister wrote:

On Feb 14, 2018 19:47, "Chris Caudle"  wrote:

On Wed, February 14, 2018 7:06 pm, jimlux wrote:

At substantially more expense, and with an experimental lattice clock,


Does that schematic figure in the paper imply that the "transportable"
strontium and ytterbium clocks are built into trailers instead of the
traditional rack enclosure?
Actually now that I look more closely it looks like maybe two trailers.
Doesn't seem like something that Jim is going to be flying any time soon.


Yes. From the Nature article text:
"The transportable 87Sr lattice clock is (compared with laboratory clocks)
designed to be compact, with robust optical parts12
. The physics
package is less than 0.6 m3 in size, and we use laser breadboards with
mechanical stress-resistant fibre couplers21
. All
components except the reference cavity of the interrogation laser are
rigidly mounted in a car trailer (size 2.2 m × 3 m × 2.2 m), and vibration
isolation is provided by rubber dampers. The trailer interior is
temperature stabilized, while the small volume of the trailer hinders air
exchange and generates hot spots with more than 10 K temperature rise.
However, the optics and the physics package are placed apart and shielded
from these and are stable to within 0.4 K after an initial temperature rise
of about 1 K. The transportable ultrastable reference cavity for the clock
interrogation lasers is rigidly mounted to endure transport12
. It was placed
next to the trailer to avoid its performance being degraded by vibrations
induced in the trailer’s air conditioning system. The vibration amplitudes
in the trailer are a factor of ten larger than under typical laboratory
conditions, leading to a corresponding increase in clock instability. A
reference resonator with lower acceleration sensitivity or an active
feed-forward system may in the future remedy this inconvenience22
."




We have discussed the desirability of suitable caves for operation of 
high quality clocks many times on this list.

Clearly this is another instance.

With respect to flying such things in space - this is the continual 
challenge - DSAC (the trapped mercury ion clock) was a couple of benches 
in a special time keeping lab when I first saw it, oh, a decade ago?. 
It will fly later this year and it's probably about the size of an 
airplane carry-on.

https://www.jpl.nasa.gov/missions/deep-space-atomic-clock-dsac/

Cold Atom Laboratory basically takes several optical benches operated by 
a team of post-docs that makes Bose Einstein Condensates (BEC) and turns 
it into a box the size of a dorm refrigerator that goes "ping" when you 
press a button and makes a BEC (in either Rb or K, as you choose).


https://coldatomlab.jpl.nasa.gov/mission/

Just as a rule of thumb, I've found that it takes about 10-20 times the 
cost to get from "benchtop prototype"(TRL 5) to "flyable unit" (TRL 6), 
as it cost to get from idea to benchtop prototype.


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Re: [time-nuts] Team of physicists repeats tvb Project GREAT

[jimlux]

On 2/14/18 6:46 PM, Chris Caudle wrote:

On Wed, February 14, 2018 7:06 pm, jimlux wrote:

At substantially more expense, and with an experimental lattice clock,


Does that schematic figure in the paper imply that the "transportable"
strontium and ytterbium clocks are built into trailers instead of the
traditional rack enclosure?
Actually now that I look more closely it looks like maybe two trailers.
Doesn't seem like something that Jim is going to be flying any time soon.


nor will tvb's brother-in-law be wearing it as a wristwatch
http://www.leapsecond.com/pages/atomic-bill/
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Re: [time-nuts] Team of physicists repeats tvb Project GREAT

[Scott McGrath]

Well it will fit in a C-130 or any commercial cargo plane by the looks of the 
trailer.So it could be a flying clock.

Content by Scott
Typos by Siri

On Feb 15, 2018, at 1:02 AM, Michael Wouters  wrote:

Sorry, missed the last character in the URL:

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.073601

On Thu, 15 Feb 2018 at 4:42 pm, Michael Wouters 
wrote:

> There's a photo here:
> 
> https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.07360
> 
> Cheers
> Michael
> 
> On Thu, 15 Feb 2018 at 1:47 pm, Chris Caudle 
> wrote:
> 
>>> On Wed, February 14, 2018 7:06 pm, jimlux wrote:
>>> At substantially more expense, and with an experimental lattice clock,
>> 
>> Does that schematic figure in the paper imply that the "transportable"
>> strontium and ytterbium clocks are built into trailers instead of the
>> traditional rack enclosure?
>> Actually now that I look more closely it looks like maybe two trailers.
>> Doesn't seem like something that Jim is going to be flying any time soon.
>> 
>> --
>> Chris Caudle
>> 
>> 
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>> 
> 
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Re: [time-nuts] Team of physicists repeats tvb Project GREAT

[Michael Wouters]

Sorry, missed the last character in the URL:

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.073601

On Thu, 15 Feb 2018 at 4:42 pm, Michael Wouters 
wrote:

> There's a photo here:
>
> https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.07360
>
> Cheers
> Michael
>
> On Thu, 15 Feb 2018 at 1:47 pm, Chris Caudle 
> wrote:
>
>> On Wed, February 14, 2018 7:06 pm, jimlux wrote:
>> > At substantially more expense, and with an experimental lattice clock,
>>
>> Does that schematic figure in the paper imply that the "transportable"
>> strontium and ytterbium clocks are built into trailers instead of the
>> traditional rack enclosure?
>> Actually now that I look more closely it looks like maybe two trailers.
>> Doesn't seem like something that Jim is going to be flying any time soon.
>>
>> --
>> Chris Caudle
>>
>>
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>
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Re: [time-nuts] Team of physicists repeats tvb Project GREAT

[Michael Wouters]

There's a photo here:

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.07360

Cheers
Michael

On Thu, 15 Feb 2018 at 1:47 pm, Chris Caudle  wrote:

> On Wed, February 14, 2018 7:06 pm, jimlux wrote:
> > At substantially more expense, and with an experimental lattice clock,
>
> Does that schematic figure in the paper imply that the "transportable"
> strontium and ytterbium clocks are built into trailers instead of the
> traditional rack enclosure?
> Actually now that I look more closely it looks like maybe two trailers.
> Doesn't seem like something that Jim is going to be flying any time soon.
>
> --
> Chris Caudle
>
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
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Re: [time-nuts] Team of physicists repeats tvb Project GREAT

[Tim Lister]

On Feb 14, 2018 19:47, "Chris Caudle"  wrote:

On Wed, February 14, 2018 7:06 pm, jimlux wrote:
> At substantially more expense, and with an experimental lattice clock,

Does that schematic figure in the paper imply that the "transportable"
strontium and ytterbium clocks are built into trailers instead of the
traditional rack enclosure?
Actually now that I look more closely it looks like maybe two trailers.
Doesn't seem like something that Jim is going to be flying any time soon.


Yes. From the Nature article text:
"The transportable 87Sr lattice clock is (compared with laboratory clocks)
designed to be compact, with robust optical parts12
. The physics
package is less than 0.6 m3 in size, and we use laser breadboards with
mechanical stress-resistant fibre couplers21
. All
components except the reference cavity of the interrogation laser are
rigidly mounted in a car trailer (size 2.2 m × 3 m × 2.2 m), and vibration
isolation is provided by rubber dampers. The trailer interior is
temperature stabilized, while the small volume of the trailer hinders air
exchange and generates hot spots with more than 10 K temperature rise.
However, the optics and the physics package are placed apart and shielded
from these and are stable to within 0.4 K after an initial temperature rise
of about 1 K. The transportable ultrastable reference cavity for the clock
interrogation lasers is rigidly mounted to endure transport12
. It was placed
next to the trailer to avoid its performance being degraded by vibrations
induced in the trailer’s air conditioning system. The vibration amplitudes
in the trailer are a factor of ten larger than under typical laboratory
conditions, leading to a corresponding increase in clock instability. A
reference resonator with lower acceleration sensitivity or an active
feed-forward system may in the future remedy this inconvenience22
."

Cheers,
Tim


--
Chris Caudle


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Re: [time-nuts] Team of physicists repeats tvb Project GREAT

[Chris Caudle]

On Wed, February 14, 2018 7:06 pm, jimlux wrote:
> At substantially more expense, and with an experimental lattice clock,

Does that schematic figure in the paper imply that the "transportable"
strontium and ytterbium clocks are built into trailers instead of the
traditional rack enclosure?
Actually now that I look more closely it looks like maybe two trailers.
Doesn't seem like something that Jim is going to be flying any time soon.

-- 
Chris Caudle


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