Hi Ole, What does 'EFOS' mean? I hadn't heard the term before.
I think I've heard the one-second lifetime figure before. I do hear mixed reports about where the conversion to atomic H occurs, and consider the jury to still be out on that question. I had thought that the volume of the storage bulb was much smaller in out maser, perhaps in the pint to quart range. For a frequency of ~1420 MHz, I guess it would take a cavity that is operating in a somewhat higher than fundamental mode if the volume is in the gallon regime as you suggest. But with the narrow gain profile width of this transition, I supposed there'd be no risk of the thing running in the wrong mode. Dana On Tue, Nov 21, 2017 at 8:14 AM, Ole Petter Ronningen <[email protected] > wrote: > On Tue, Nov 21, 2017 at 2:50 PM, Attila Kinali <[email protected]> wrote: > > > [...] The advantage of the platinum valve > > system is that it "generates" single atom Hydrogen, as required > > by the maser. > > > Picking nits here.. It was my understanding that the splitting of molecular > hydrogen into atomic hydrogen happens using RF in the dissociator - not in > the platinum leak valve. Is my understanding incorrect? > > > > Within the cavity there is a small glass bulb that keeps the atoms > > in the right position of the cavity field. > > > 4.5 liters in EFOS type masers - so not *that* small. I believe other > masers are the same order of magnitude. > > > > Yes, IIRC normal numbers are several 10s to 100s of wall collisions > > before the atom loses its state due to wall colisions and without > > contributing to the signal. > > > > Lifetime ~1 second I think > > > > > I've long wondered what causes the slow frequency drift, typically > > amounting > > > to about 3E-14 over a time span of several months. > > > > Mostly changes in the wall coating leading to a different wall collision > > shift and mechanical changes of the cavity dimension (think air pressure > > and creep) leading to a different cavity pulling. To a lesser extend > > it's the changes in the quality of the vacuum and number of Hydrogen > atoms > > in the cavity. > > > Also aging of electronic components - coarse tuning of the cavity is done > by temperature, and any drift if the temperature-sensor/amplifiers etc will > result in drift. At least for EFOS type masers. > > Ole > _______________________________________________ > 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. > _______________________________________________ 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.
