[time-nuts] GSP clock stabilitiy, Rb vs Cs

[Scott McGrath]

A joke I think :-) referring to dihydrogen monoxide fountains

Sent from my iPhone

On May 7, 2013, at 12:49 AM, Magnus Danielson <magnus at rubidium.dyndns.org> wrote:

> Rather the opposit. They will be really compact and can have long observationtime.
> Cheers
> Magnus
> 
> -------- Originalmeddelande --------
> Från: Bob Camp <lists at rtty.us> 
> Datum:  
> Till: Discussion of precise time and frequency measurement <time-nuts at febo.com> 
> Rubrik: Re: [time-nuts] GSP clock stabilitiy, Rb vs Cs 
> 
> Hi
> 
> Fountain's don't work very well in zero G….:)
> 
> Bob
> 
> On May 6, 2013, at 12:23 AM, Magnus Danielson <magnus at rubidium.dyndns.org> wrote:
> 
>> On 05/06/2013 02:29 AM, Mike S wrote:
>>> On 5/4/2013 2:40 PM, Attila Kinali wrote:
>>>> Can anyone shed some light on why the GPS Cs beams have a worse stability
>>>> than the Rb vapor clocks?
>>> 
>>> I don't know, but it makes me wonder about things like
>>> 
>>> 1) How sensitive is each to C-field tuning - i.e. for the same change in
>>> C-field, by how much does each type change in relative frequency? (or
>>> maybe it's exactly the same, I know nothing about the Zeeman effect) I'd
>>> think there would be orbital changes in frequency, after all, it's
>>> orbiting a big magnet.
>> 
>> Rubidium is more sensitive to C-field than Caesium.
>> 
>>> 2) How tight a lock can be obtained on each? i.e. might the physical
>>> realizations of Rb clocks have a higher Q-factor?
>> 
>> The Q-value depends on the observation time, and for a Cs-beam this translates into beam-length assuming constant speed. Foutains has much better Q since they have longer observation time. H-masers started as a beam with a "bounce-box" to prolong the observation time.
>> 
>> Cheers,
>> Magnus
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