[time-nuts] Exact Rubidium frequency

Brooke Clarke brooke at pacific.net
Sat Jun 30 21:49:44 EDT 2007

Hi Hal:

The Zeeman effect.
See page 6 at:

Both the HP 5060 and the FTS4060 have a jack to allow you to feed an audio 
frequency sweep into the tube.  By monitoring the beam current you can see a 
peak (or dip, I forget which) when the Zeeman effect takes place.

You need to know the specifics of the physics package to know what the Zeeman 
frequency is supposed to be.  Then you can feed that to your Cs standard and 
tweak the C field for the peak (dip?) and it will be on frequency.

Have Fun,

Brooke Clarke

Hal Murray wrote:
>>I have also seen the frequency of a Hydrogen Maser given as both
>>1,420,405,751 Hz and ...752 Hz.  I would be very surprised if the
>>frequency was an exact whole number of Hertz different from Caesium,
>>so perhaps this is just rounded for convenience as again it can be
>>steered to anywhere you like? 
> If Hydrogen and Rubidium clocks can be tweaked slightly, I assume Cesium can 
> be too.
> How do people who build Cesium clocks know what the "right" value is?

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