Or you could try playing with this, http://www.teachspin.com/instruments/optical_pumping/index.shtml and make your own. Only about $15K Robert G8RPI.
--- On Sun, 21/3/10, John Miles <jmi...@pop.net> wrote: From: John Miles <jmi...@pop.net> Subject: Re: [time-nuts] HP 5065A performance vs. others To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Date: Sunday, 21 March, 2010, 22:58 > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on > Behalf Of Bob Voelker > Sent: Sunday, March 21, 2010 1:59 PM > To: time-nuts@febo.com > Subject: [time-nuts] HP 5065A performance vs. others > > > As several postings have indicated, the performance of the HP > 5065A is better > than many of the other rubidium standards. What enables the HP 5065A to > achieve better performance?--Is it the physics package or the particular > control system implemented in electronics? Would it be possible to > achieve the HP 5065A's performance by modifying a more commonly > available rubidium such as the LPRO? Would an ensemble of LPROs > match a single HP 5065A in performance? > > Bob I think those are all open questions, because it's not immediately clear what limits the performance of the smaller telecom-grade physics packages, or what low-hanging fruit might be left on the tree. For instance, how important is the length of the path the light takes through the filter cell and/or resonance cell? It's obviously a lot longer in a 5065A. Or is it HP's proprietary buffer-gas mixture that makes most of the difference? Is there something special about HP's lamp? Is their microwave synthesizer that much better? HP's temperature stabilization is better than the LPro's -- so maybe it would help if you just moved the LPro's Rb assembly into an outer oven, separate from the rest of the electronics. How important is all that mu-metal shielding on the 5065A, given that most people these days would care more about stability than absolute accuracy (thanks to GPS)? Someone with more free time should tackle these questions. :) F. G. Major's book would be a good starting point, and this paper on laser-pumped Rb clocks also has a lot of hints about what limits the performance of ordinary sources: http://tf.nist.gov/general/pdf/1219.pdf . They used the cell from a commercial Rb standard in their experiment, although they didn't say which one. If nothing else, you can infer from this paper that the path length through the resonance cell isn't a huge deal. -- john, KE5FX _______________________________________________ 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.