[time-nuts] cesium clocks..

[Bruce Griffiths]

Chuck Harris wrote:
> This is a chicken vs egg sort of problem.  When I took apart the oven
> on my 5065A rubidium, it looked to me as though the enamel insulated
> nichrome wire developed a short about 50% into the coil, and wiped out
> the transistor.  It also heated the rubidium lamp hot enough to reflow
> the solder on its circuit board and thoroughly char the PCB's epoxy.
>
> I am not sure how the quartz ovens are wound (I suspect they are the
> same), but with the rubidium ovens, the nichrome wire is wound as a
> bifilar loop.   This is done for two reasons, 1) to cancel the magnetic
> fields, and 2) to make the start and finish wires of the winding happen
> at the end of the oven where the terminals are.
>
> -Chuck Harris
>
>   
An Ayrton-Perry style winding will also have low magnetic field.

Bruce