[time-nuts] Storage of Rb & Cs standards?

[Poul-Henning Kamp]

In message <4124F77D.8020006 at pacific.net>, Brooke Clarke writes:
>Hi:
>
>The manual for the current Symmetricon 4065 Cs standard says to store it with the ion pump running.  The manual for the HP 4065 Rb standard says to connect a low current source to a couple of wires when it's stored.
>
>Can someone say why you should keep the ion pump ging and what
>happens if you don't?

To keep the vacuum intact.  The ion pump creates a very deep vacuum
very slowly.  Normally it can keep up with any leakage just fine,
but if the tube is stored for long time it can take similarly long
time for the ion pump to evacuate the tube.  HP has a procedure for
thre 5061 where they apply a higher voltage to the ion pump to speed
up the process.

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