From: "Bill Hawkins" <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Time Nuts at PTTI this past week Date: Sat, 9 Dec 2006 10:11:05 -0600 Message-ID: <[EMAIL PROTECTED]>
> Ah, yes, the C field. A change in magnetic field can change > the clock frequency. Parts in 1e-14 are exceedingly small. If you run a modern clock, it will adjust the C field for the propper feature separation in the measurements. This way, vector sum of the C field applied and the external magnetic sources as they affect the beam will be measured on its feature effect and then the C field is steered to the "propper" separation. As always, there is no perfect cancelation, but some of the external field should be compensated. However, avoidance of strong fields and change of strong fields is allways a good precaution. > Is it necessary to correct for the Earth's magnetic field > when the clock travels? > > Bill Hawkins > > Actually, that's a test that can be done at home with a > couple of 2-3 foot diameter solenoid coils. Be tough to > find an ammeter good to 1e-15, though. The ampmeter does not have to have that accuraccy. For cesium, the frequency shift is 42.745 GHz/T^2. A fairly normal ampmeter will suffice to predict the shift. The actual added DC shift of the magnetic field you acheive on the beam is a much larger error-factor than your amp-meter. But yes, you should certainly be able to measure it at home. I greatly enjoyed measuring the Rabi-Ramsey separations on my Cs beam by inserting my own 12.6 MHz signal which I swept with my network analyzer. I then modulated the detected level through a double-balanced mixer with 12.6 MHz signal and tossed that in on the measurement port. Then I actually had built myself a 9.192 GHz network analyzer. That was pretty fun. :) Cheers, Magnus _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
