[time-nuts] Cesium vs H Maser clocks

[Mike S]

At 08:20 PM 11/28/2008, Tom Van Baak wrote...
>If you really get into the details of the physics, remember that no
>commercial or laboratory Cs clock actually resonates at precisely
>9 192 631 770.000 Hz. There are corrections for magnetic fields,
>velocity of atoms, temperature, cavity design, even for gravity; a
>whole bunch of interesting effects.

Isn't the temperature the _only_ thing to correct for?

The definition of the second is "...the duration of 9 192 631 770 
periods of the radiation corresponding to the transition between the 
two hyperfine levels of the ground state of the cesium 133 atom." (and 
affirmed by the CIPM in 1997 that this definition refers to a cesium 
atom in its ground state at a temperature of 0 K)

That other factors can change the relative frequency of different Cs 
clocks is a problem with the definition, not an indication that any 
particular one is better than another. If a magnetic field changes the 
relative frequency, but that isn't reflected in the definition, is it 
not the definition which is faulty, and not the timepiece? The second 
is imprecise in this regard.