[time-nuts] Zeeman frequencies

Tom Van Baak tvb at leapsecond.com
Wed Jan 12 20:58:29 EST 2005


> I just got off the phone with Corby Dawson who was helping me through 
> the power-up of my newly acquired 5061A.  (The replacement FTS tube had 
> slipped during shipment, breaking the HV connector for the ion pump.  
> It's fixed now, and I have a nice green "Continuous Operation" light.)

Good news on your FTS. And now John now joins the
"green light" club!

> Anyway, I asked him about the Zeeman frequency for an FTS vs HP tube.  
> His answer was that the proper frequency depends on the electronics in 
> the chassis, not the tube.  HP specified two different frequencies, 
> 42.82 (in the early manuals) and 53.53kHz.  Either one will work, but 
> the higher frequency gives slightly better accuracy (maybe a sharper 
> peak, so better resolution?).  The 5061B manual says that 100Hz of 
> Zeeman offset is equal to 1x10e-12.

Thanks for the 53.53 kHz number. And your 100 Hz ~ 1e-12
quote approximately agrees with the 1% ~ 3.6e-12 number
I gave earlier. So any signal generator good to 3 digits ought
to be sufficient to tune the Cs tube to 1e-12.

/tvb






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