Hi A cryo pump will get you into reliability issues if run 24/7. It also is doubtful that you will be able to maintain the vacuum level over long periods.
Bob > On Jan 11, 2017, at 12:09 AM, Bruce Griffiths <bruce.griffi...@xtra.co.nz> > wrote: > > One could always use a cryo pump. > The following paper is a summary of the current state of the art for rubidium > vapour frequency > standards:http://www.euramet.org/Media/docs/Repository/A169/IND55/micalizio_02182015.pdf > > Bruce > > On Wednesday, 11 January 2017 5:15 PM, Ole Petter Ronningen > <opronnin...@gmail.com> wrote: > > > Add to this ion-pumps (in the case of EFOS type masers 2 every ~2 years), > plus substantial tooling (turbomolecular vacuum pump, anyone?) to service > the thing - unless you want the manufacturer to do so.. > > Ole > > On Tue, Jan 10, 2017 at 11:12 PM, Dr. David Kirkby (Kirkby Microwave Ltd) < > drkir...@kirkbymicrowave.co.uk> wrote: > >> On 10 January 2017 at 15:35, Ole Petter Rønningen <opronnin...@gmail..com> >> wrote: >> >>> ... having said that, I for one think I'm with Bob on this one. The thing >>> about masers are that they are big. At least active masers. And they >>> require a substantial volume be kept at ultra high vacuum - which is not >>> trivial, especially not in a homeshop. The cavity needs to be kept at a >>> temperature stable to 0.001 degree C. With 4-5 magnetic shields. Add to >>> this costly pumps to keep the vacuum this low even if you succeed at >>> reaching that vacuum.. There's easily 1-2KUSD running cost per year just >> to >>> keep the maser running. >>> >> >> Looking at the Microsemi MHM 2010 Active Hydogen Maser data sheet, the >> maser has a peak power of 150 W and an operating power of 75 W. Based on a >> power consumption of 75 W, that is 657 kW hr / year of energy. I pay around >> £0.20 (GBP) per kW hr for electricity, so that's £131 (GBP) annually. I >> believe electricity is cheaper in the USA than here in the UK, but >> converting £131 (GBP) to USD, that's around $161/year in electricity.. So >> running costs don't seem to be an issue. >> >> But I must admit, the thought of spending a lot of time/money to build >> something I could have bought for a lot less with higher performance is not >> that attractive, although of course there would be a satisfaction from >> building it yourself. >> >> Dave >> _______________________________________________ >> 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. > > > > _______________________________________________ > 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.