[time-nuts] Re: Project Great

[Magnus Danielson]

Hi Michael,

Thanks for that plot. I think it sumarizes fairly well what typical 
devices of today achieves.

There is rubidiums and quarts that go into the 1E-14s, but most do not. 
The old plot uses a "span" for the different technologies and that helps 
to avoid the "but this device/product" types of issues.

The optical clocks is not really on there, but the modern cold Rb etc. 
should be there.

One clearly sees the benefit of CSOs and there should not be to 
surprising to see that they are used in other clocks to improve 
performance in that range.

I clearly miss out on having CSOs in my arsenal, otherwise that plot 
illustrates much of my experience of measuring these devices in my lab.

Cheers,
Magnus

Den 2021-12-02 kl. 07:13, skrev Michael Wouters:
> Hello Jim
>
> Here is a relatively up to date plot that I made for the T&F course we give.
> Labels are a bit misaligned courtesy of PowerPoint,
> No CSAC, but there is an SDI cold Rb and a UAdelaide CSO.
> Slightly different perspective to the Schmittberger et al plots that
> Tom B referenced,
>
> Cheers
> Michael
>
> On Mon, Nov 29, 2021 at 9:07 AM Lux, Jim <jim at luxfamily.com> wrote:
>> On 11/28/21 1:06 PM, Marek Doršic wrote:
>>> Hi,
>>>
>>>       I'm also one of those fascinated by Project Great and this was The project inspired me to start with time related stuf.
>>>
>>> Can Cs clock be avoided by prolonged period at high altitudes? Assume you can spend a month at the summit. Is e.g. the Rb drift stable enought to compensate and obtain viable results?
>>>
>>>     .marek
>>
>> Sadly, no...  That's what the Allan Deviation tells you.  It says
>> "here's the best you can do, at this averaging time".  And a lot of
>> sources may have a low flat spot in the curve, but it eventually trends
>> up. Except for primary standards like Cs beam.
>>
>> So if a Rb plateaus at, say, 1E-12, that's the best you're going to do.
>>
>>
>> Speaking of which, does anyone have a link to a "current state of the
>> art" graph.
>>
>> Kind of like this one from Vig, but with specific new technologies like
>> CSAC etc
>>
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