Hello Time-Nuts, For the past several months I have been investigating the change in aging rate of a rubidium oscillator with change in pressure. This has been done with an operating oscillator in a temperature controlled vacuum chamber.
Obviously, the frequency changes (a lot) with pressure changes due to 'oil canning' of the rubidium cell. What I have been interested in is the behavior of the change in frequency (aging) with pressure. If an inflection point can be found or the aging minimized there is potential to have an oscillator that performs very well. The only 'change in aging' mechanism that I have run across is helium permeation of the rubidium cell. FEI has a paper published when the oscillators for the first GPS satellites were being developed. Temex/Spectratime is the only company that I have seen that addresses this in their specifications. So far, I have been operating in the 10-50 Torr range and have seen a very definite trend on aging with pressure. But there is much more research to do. My big question is - what pressure related mechanism might affect aging? I would think that helium permeation would have a somewhat longish time constant. I'm wondering if anyone from the group has some experience in this area? Thanks in advance for any help. Regards, Skip Withrow _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
