[time-nuts] OCXO sensitive to gravity

Magnus Danielson magnus at rubidium.dyndns.org
Fri Aug 14 07:52:14 UTC 2009


Rick Karlquist wrote:
> Tom Duckworth wrote:
>> The orientation change is due more to the earth's magnetic flux effect on
>> the oscillator, and less so from gravity.
>>
>> Tom
>> Tom Duckworth
>> tomduck at comcast.net
> 
> Sorry, this is simply incorrect.  Magnetic flux from the
> earth has no effect on quartz oscillators.  There is no
> mechanism there.  Acceleration definitely affects quartz.
> 
> Magnetic flux could have an effect on atomic standards,
> but they normally have magnetic shielding to mitigate
> this effect.  Orientation (or at least acceleration)
> can affect cesium beam standards because the atoms
> are flying.  Len Cutler put in a fix to mitigate against
> this in the 5071A CBT.  AFAIK, orientation doesn't affect
> Rb standards.

Magnetic flux do influence rubidium standards as well, infact they are 
more sensitive than cesium. Again, magnetic sheilding is used, but to a 
less excessive level than cesium and hydrogen. All atomic clocks do in 
their physics depend on the magnetic field, and modern cesium clocks use 
  nearby sidebands (mf=-1 and mf=+1) which has much higher dependence on 
magnetic flux as gears to steer the magnetic flux for the center (mf=0) 
pidestal.

However, rubidiums optically pumped gas cells (which is a more accurate 
description of what we call "normal" rubidium clocks) has a number of 
severe limitations, which makes excess shielding pointless.

A rubidium fontain however... now that is a different matter altogether.

Cheers,
Magnus




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