[time-nuts] Cold Rubidium?

[Richard (Rick) Karlquist]

Good questions, Hal.

This reminds me of the HP Cesium Beam Tube useful
life.  The standard tube, at least, is such that it is unlikely
to last long enough to completely use up the cesium.
Then there is the rest of the instrument.

My experience with the HP Rubidium units is that if
you just flood the cell, there is a problem of excess
rubidium condensing in inconvenient places.

A user installable Rb cartridge may be problematical
in that I suspect that they have to pump down the unit
to a high vacuum, then break an Rb capsule, and then fire
a getter, etc.  I can't imagine they would needlessly
saddle the user with having to ship the unit back if
there was a reasonable alternative.

Rick

On 11/7/2019 6:15 PM, Hal Murray wrote:
> 
> p.boven at xs4all.nl said:
>> We were seriously considering the Muquans clock for a radio astronomy
>> project. However, the company explained that the device has to be  returned
>> every 3 to 5 years for re-filling. Given the very remote  location we were
>> going to put these in, that was out of the question for us.
> 
> What's the MTBF of that sort of gear?  How often can you repair it on site?
> 
> Did you ask about a larger container for whatever needs re-filling?
> 
> How big is the unit?  Is whatever needs re-filling removable so you don't have
> to ship the whole thing?  (I'm assuming that you have to swap out technicians
> occasionally so there is occasional transportation to the remote sites.)
> 
>