[time-nuts] HP 5061Cs reference question

[Magnus Danielson]

Tom,

On 12/06/2014 06:04 PM, Tom Van Baak wrote:
> Paul,
>
> There are 7 peaks total, about 40 kHz apart (on my 5061A). If you're talking about just the central peak, there are two smaller peaks on either side, about 1 kHz apart. The exact value depends on internal magnetic field, which is specific to each beam tube design.
>
> For some measurements of all the peaks, have a look at:
> http://leapsecond.com/pages/cspeak/

These are the 7 Zeeman pedestals, and on top of them you have the Ramsay 
fringes. You can indeed lock onto the wrong Ramsey-fringe, but they too 
have amplitude differences. For a normal tube, they are quite 
significant, but if you look at the Ramsay fringes on the NIST-F1, they 
are much denser and looses amplitude much slower, so you need to pay 
more details of which fringe you use. The density of the Ramsay fringes 
is due to the observation time, which has been one of the driving forces 
to develop hydrogen masers and cesium fountains, but for a simple cesium 
tube, it's a few dm of distance and the average speed of the cesium steam.

> You can play with the C-field in addition to playing with peaks:
> http://leapsecond.com/images/cfield.gif  (578 x 4610 pixels)

Which is a good illustration. It would be good.

> For more details search the archives for the word Zeeman. For example:
> https://www.febo.com/pipermail/time-nuts/2005-April/018171.html
>
> A nice description from hp how a cesium beam standard works:
> http://leapsecond.com/museum/hp5062c/theory.htm

Do check the FTS-4065C manual as I just uploaded. Good complementary 
information.

Cheers,
Magnus