> My understanding is that the precise cesium hyperfine transition energy, > and hence microwave frequency, is dependent upon the applied C-field, > and the field setting to select a particular transition is the same for > all clocks (which is why these are primary standards). The C-field is > set by applying an LF signal at the correct frequency to cause Zeeman > splitting, and optimizing the C-field to peak the splitting.
It's the same for all cesium tubes of the same design but over the decades a number of different tubes have been designed. 42.82 kHz (older model 5061) 70.40 kHz (model 5062c) 53.53 kHz (newer 5061A/B and 5071A) See this 2005 time-nuts posting: http://www.mail-archive.com/time-nuts@febo.com/msg00233.html The Zeeman shift would also be different among the one of a kind cesium standards that national laboratories build. But the key is that based on the beam design the zeeman shift can be calculated and thus compensated for. What makes a standard primary is if all the frequency shifts can be calculated (not measured) as well as the magnitude of all error sources. For a great example of this read: http://www.boulder.nist.gov/timefreq/general/pdf/1497.pdf including table 3 and table 4. > So, shouldn't the Zeeman frequency always be 42.82 Khz, which is what > I've seen in every reference? But, my 5061A with a high-performance tube > has a sticker that says 'Zeeman freq 53.53 Khz'. I can indeed get Zeeman > splitting at that frequency with a C-field setting of 3.45, but is this > correct? If so, why? (BTW - I don't seem to be able to get any splitting > at 42.82 Khz) > > Confused, > Bill There's also a nice description here: http://www.leapsecond.com/museum/hp5062c/theory.htm Homemade plots of the 7 cesium hyperfine peaks here: http://www.leapsecond.com/pages/cspeak/ /tvb _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.