And cryo means ultra high purity helium. I learned about that the hard way. They don't like pumping gravel (solidified trace amounts of oxygen, argon, etc.)
-Bob On Wed, Sep 1, 2010 at 5:37 PM, J. Forster <j...@quik.com> wrote: > Yup. If you do use oil, you need an LN2 trap. > > -John > > =============== > > > Hi > > > > My guess is that you either need a cryo pump or ion pumps and a very good > > seal. > > > > Bob > > > > > > > > On Sep 1, 2010, at 5:15 PM, Robert Darlington <rdarling...@gmail.com> > > wrote: > > > >> You can pickup oil diffusion pumps pretty inexpensively. They're not > >> quite > >> ion pumps but they get you way down there and they're fast. With proper > >> traps you don't really have to worry about coating your experimental > >> physics > >> package with oil. They're cheap to run and easy to maintain. Ion pumps > >> are > >> about as simple as things get and could probably be made very easily by > >> some > >> of us "vacuum-nuts" but I never had the need. Turbo pumps probably > >> won't do > >> the job and they're expensive and unforgiving. Not only did one of mine > >> crash, it crashed when a sputtering gun melted through. 80,000 RPM > >> spinning > >> foil blades don't like hitting the gun cooling water very much! > >> > >> Good luck! > >> > >> -Bob > >> > >> On Wed, Sep 1, 2010 at 2:30 PM, Chris Howard <ch...@elfpen.com> wrote: > >> > >>> > >>> > >>> Given the quality of vacuum the manual seems to imply, I'm guessing > >>> this > >>>> wont cut it. I'll bet that even low impurity Teflon has a long > >>>> bakeout > >>>> period. > >>>> > >>>> > >>> Too bad they don't have some kind of "getter" to allow lower vacuum > >>> specs. > >>> I expect they thought of that. > >>> > >>> The thing does sound like a giant hydrogenated vacuum tube. > >>> > >>> > >>> > >>> _______________________________________________ > >>> 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. > _______________________________________________ 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.