[time-nuts] Hydrogen Maser KIT! Update #1

Mark Kahrs mark.kahrs at gmail.com
Tue Nov 4 08:54:04 EST 2014

There's been a  fair number of papers from Hahvahd about bulb coating for
masers.  Interestingly enough, here's a patent:


from 1972.

I had to figure this out, but Yuri is referring to flourophosgene a.k.a.
carbonyl flouride.

If you'd like to read a really nice detailed paper on bulb coating for Rb
cells, try this one out:


On Mon, Nov 3, 2014 at 3:46 PM, Chuck Harris <cfharris at erols.com> wrote:

> Hi Yuri,
> It would be a very good idea to keep the temperature of
> the nichrome wire low, and that might be the biggest problem
> with the vacuum deposition technique... the wire could get
> too hot in some places, and stay too cool in others.
> A really uncontrolled experiment, aka: a thermal wire stripper,
> gets covered with white snow from the teflon vapor released
> while stripping teflon wire.
> -Chuck Harris
> Yuri Ostry wrote:
>> Hello,
>> Monday, November 3, 2014, 5:40:30, Chuck Harris wrote:
>> C> I would think that making the teflon coating would be pretty easy.
>> C> What I would try is to put a nichrome boat, and some teflon into the
>> C> vessel, and pull it down to a good vacuum.  Then heat up the boat,
>> C> and the teflon should sublime, and condense on the walls of the
>> C> vessel.
>> C> The nichrome boat could be something as simple as wrapping the nichrome
>> C> into a solenoid form around some teflon rod.
>> C> -Chuck Harris
>> Teflon decomposes at high temperatures, releasing some sublimate and a
>> lot of really nasty chemicals, like fluorfosgen. There is a chance
>> that really thin even coating can be produced this way, but a lot of
>> experimentation would be needed.
>> I would try to take samples of PTFE-insulated hookup wire (from different
>> manufacturers, say white Alfa or Belden wire and russian MGTF wire that
>> use
>> slightly different PTFE formula) and try to make coating inside glass
>> tube samples, using copper wire as heater by itself.
>> I doubt that there will be good results, though. "Classic" way with
>> thin slurry application and heating to teflon melt point to make solid
>> film may be more "realistic".
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.

More information about the time-nuts mailing list