[time-nuts] Zeeman freq question

Tom Van Baak tvb at LeapSecond.com
Sat Jul 19 23:01:23 EDT 2008

> I noticed that all the Zeeman freqs seem to be specified
> to 10 Hz resolution.  Were the systems designed with the
> c-field set to make this happen or are more precise values
> available?  It seems that such an important value would be
> specifed with greater precision.  I have my FEI-5650A
> program set up to generate these standard Zeeman values.
> I can get 0.01 Hz resolution if more accurate values are available...

Right, but the precision of the Zeeman frequency has but
a small effect on the accuracy of the Cs resonance.

As one example, based on the formula under Figure 10 in:

f = 9192631770 + 8.7026x10-10fz2

a 10 Hz Zeeman difference at 42.82 kHz makes only a
0.000745 Hz difference out of 9192631770 Hz, or 8.1e-14.
Given that these old standards are only spec'd parts in ten
to the 11th to maybe 12th in accuracy the 10 Hz margin for
the Zeeman input would appear more than adequate.


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