From: "John Franke" <[EMAIL PROTECTED]> Subject: Re: [time-nuts] Home built Ammonia cell std !! / Home built cesiumclocks??? Date: Sun, 29 Jun 2008 12:20:28 -0400 Message-ID: <[EMAIL PROTECTED]>
> Now that is something I am interested in doing. I finally secured use of a > diffusion pump at a local university and expect to be making my first sealed > all-glass absorption cells this fall. The ammonia pressure needs to be > around 8-10 microns. I will be trying for a double pass cell giving a pass > length between 10 and 12 feet. The first ammonia atomic clock used a path > length of 33 feet. The cell was made from waveguide and did not hold a > charge due to leaks or the ammonia reacting with the gold plated waveguide. > I believe the best ammonia based standard was only good to 10 ^ -8 in > frequency stability. More like 5E-11 both in cavity pulling and collision effects. Cavity pulling was reduced in 1961 by means of automatic cavity tuning. Recall that you do state-selection on the ammonia beam. An electrostatic quadrapole configuration was used. Just like a Hydrogen maser. Cheers, Magnus _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
