Hi The outer can is at best only “sort of” sealed.
Bob > On Mar 22, 2017, at 10:58 AM, jimlux <jim...@earthlink.net> wrote: > > On 3/22/17 4:28 AM, Bob Camp wrote: >> Hi >> >> In this case, the vacuum might work against you. You change the pressure >> outside >> the package and you get a flex. Flex translates to dimensional changes. That >> gives you >> a frequency shift. People make absolute pressure sensors this way :) Rb’s >> are by no >> means the only frequency standard impacted by this effect. Precision OCXO’s >> have the >> same issue. >> >> If you had enough room inside the package, you could do a “can in a can” >> sort of approach. >> The outer vacuum sealed can flexes. The inner vacuum sealed can does not see >> anything. >> You don’t eliminate the sensitivity this way, you do attenuate it quite a >> bit with each layer. >> The question then becomes - is is worth the increase in size? Since the >> pressure sensitivity >> is well below many other environmental factors …. probably not. >> > > The CSAC is a can within a can (or more properly, the physics package is > inside a sealed can) but I don't know if there's vacuum inside the can. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
