Hydrogen Maser KIT! Update #1
Jim,
On 11/03/2014 12:42 AM, Jim Lux wrote:
On 11/2/14, 3:09 PM, Magnus Danielson wrote:
Bob,
Yes, but your Q will suffer.
Yes, I've dug out aged papers. I was sad to see that JPLs server was
taken down before I got to download their wealth of papers. Naturally it
happen just after I found out it also had a hydrogen maser section, but
also Chuck's papers was lovely to have collected in that form.
which server was that? I know they rearranged a lot of the technical
report servers, and then there was that "we don't know if it's export
controlled, so take it off line until we figure it out" episode.
meterology.jpl.nasa.gov as far as my memory goes. I think it was
killed of in a raid against old servers, at least that is what you said
was likely when we talked about it some time back.
It's a pitty, as it was a neat collection of articles. Such sets on a
particular topic is a useful way of finding them, even if the articles
is still available in some large archive system, you need to know what
search terms will turn out good.
These articles where already published at various places, so it should
have already been passed through review and been approved for publication.
I don't want to bother Chuck to send me EVERYTHING, even if I would
like to have the full set.
It might still be there, but at a different URL. There's been a
significant amount of reorganization within JPL over the past couple
years. The same people are probably in the same offices and working
with the same colleagues, but the name of the group and/or it's number
might have changed.
Along with this, there's been a general reorganization of websites to
make them more consistent, but it's a "when we have time and someone to
do it" kind of thing for most sections/groups. If you get lucky,
there's someone in the group who gets ambitious and does it.
Yes. The pitty was that someone had already been doing that work, and it
was scrapped. Even if the physical machine can be scrapped, the site
could continue as just a small side-kick to the larger sites.
The clock guys are in Section 335 (which also does stuff like GPS and
measuring the Earth's rotation, and science done with GPS propagation)
Still not been walking those halls, knocking those doors.
A bit of googling did not find a public org chart.. there ARE org charts
for some of the other sections, but "he/she who runs the website has to
get the approvals for public release" and some sections/groups are more
enthusiastic about this than others. The websites are not done by some
centralized organization.
And, the org charts aren't necessarily up to date (by years, in some cases)
Organization charts aside, it was a nice little site and I miss it. It
was good PR for the good work being done.
Cheers,
Magnus
Hi
On Nov 2, 2014, at 6:59 PM, John Miles john@miles.io wrote:
Yes, but your Q will suffer.
Ok, so it might / might not work depending on how high a Q it needs to start
functioning. I think I might try it before I went crazy coating he bulb. There will
be a lot of weird things to debug and associated tear downs to find them.
Having a fragile bulb coating to deal with on top of everything else might just
be more than can be dealt with.
With lower Q, you should still be able to get some usable discriminator action in passive mode. In that scenario an external 1420 MHz pump signal is needed to maintain the stimulated-emission process while new H atoms are coming into the storage bulb. I imagine you'll want to try that at first, in any event, just so you can observe the hardware actually doing something. You should see some signs of frequency discrimination long before you observe self-sustaining radiation, if I understand the process right.
Once the line width is narrow enough, through a combination of the right inlet pressure, bulb coating, cavity Q, and intercession from St. Ramsey, thermal energy is enough to sustain the "chain reaction." In other words, photons from random spontaneous-emission occurrences will be retained in the cavity rather than lost, leading to coherent stimulated emission without any outside help. But the odds of getting all of those factors right the first time don't seem good.
Yes, exactly. Way to many variables to expect it all to “just come together”. To many things like an un-noticed 60 Hz field to mess you up. Not that anyone I know has ever had that problem ….. (in the last say week …).
Bob
-- john, KE5FX
Miles Design LLC
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I would think that making the teflon coating would be pretty easy.
What I would try is to put a nichrome boat, and some teflon into the
vessel, and pull it down to a good vacuum. Then heat up the boat,
and the teflon should sublime, and condense on the walls of the
vessel.
The nichrome boat could be something as simple as wrapping the nichrome
into a solenoid form around some teflon rod.
-Chuck Harris
Bob Camp wrote:
Hi
It’s been way too many years since my last Maser play session …
Will it fire up without the Teflon coating on the bulb? Yes it works better
with the Teflon (less wall interaction). Getting the bulb re-coated might be a
major pain. It does look ugly in it’s current state. I’m wondering about just
stripping the bulb and then seeing what works and what does not.
Bob
In retrospect, it looks like their teflon coating is even simpler
done. It looks like what they did is take very finely sectioned
teflon powder, and make a slurry in probably acetone.
They cleaned the vessel very well first with acetone and second,
probably a little distilled water to etch the glass slightly,
and then put the teflon/acetone slurry in the bulb, slooshed it
around a bit to cover the walls, and then drained it all out.
When the acetone evaporated, the teflon powder would remain on
the walls.
I've seen a nearly identical coating every time I take a can of
teflon spray lubricant/mold release, and spray it on something.
-Chuck Harris
I would think that making the teflon coating would be pretty easy.
What I would try is to put a nichrome boat, and some teflon into the
vessel, and pull it down to a good vacuum. Then heat up the boat,
and the teflon should sublime, and condense on the walls of the
vessel.
The nichrome boat could be something as simple as wrapping the nichrome
into a solenoid form around some teflon rod.
-Chuck Harris
Bob Camp wrote:
Hi
It’s been way too many years since my last Maser play session …
Will it fire up without the Teflon coating on the bulb? Yes it works better
with the Teflon (less wall interaction). Getting the bulb re-coated might be a
major pain. It does look ugly in it’s current state. I’m wondering about just
stripping the bulb and then seeing what works and what does not.
Bob
Hi
On Nov 2, 2014, at 9:49 PM, Chuck Harris cfharris@erols.com wrote:
In retrospect, it looks like their teflon coating is even simpler
done. It looks like what they did is take very finely sectioned
teflon powder, and make a slurry in probably acetone.
They cleaned the vessel very well first with acetone and second,
probably a little distilled water to etch the glass slightly,
and then put the teflon/acetone slurry in the bulb, slooshed it
around a bit to cover the walls, and then drained it all out.
When the acetone evaporated, the teflon powder would remain on
the walls.
If it’s that simple, then going crazy over the coating as I was suggesting isn’t really needed.
Bob
I've seen a nearly identical coating every time I take a can of
teflon spray lubricant/mold release, and spray it on something.
-Chuck Harris
I would think that making the teflon coating would be pretty easy.
What I would try is to put a nichrome boat, and some teflon into the
vessel, and pull it down to a good vacuum. Then heat up the boat,
and the teflon should sublime, and condense on the walls of the
vessel.
The nichrome boat could be something as simple as wrapping the nichrome
into a solenoid form around some teflon rod.
-Chuck Harris
Bob Camp wrote:
Hi
It’s been way too many years since my last Maser play session …
Will it fire up without the Teflon coating on the bulb? Yes it works better
with the Teflon (less wall interaction). Getting the bulb re-coated might be a
major pain. It does look ugly in it’s current state. I’m wondering about just
stripping the bulb and then seeing what works and what does not.
Bob
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and follow the instructions there.
I guess I have to wonder why Corby felt it necessary to remove
the coating. I think it was always motley looking.
And,
If it was very easy to remove, and I suspect it would be, it
is probably equally easy to apply.
-Chuck Harris
Bob Camp wrote:
Hi
On Nov 2, 2014, at 9:49 PM, Chuck Harris cfharris@erols.com wrote:
In retrospect, it looks like their teflon coating is even simpler
done. It looks like what they did is take very finely sectioned
teflon powder, and make a slurry in probably acetone.
They cleaned the vessel very well first with acetone and second,
probably a little distilled water to etch the glass slightly,
and then put the teflon/acetone slurry in the bulb, slooshed it
around a bit to cover the walls, and then drained it all out.
When the acetone evaporated, the teflon powder would remain on
the walls.
If it’s that simple, then going crazy over the coating as I was suggesting isn’t really needed.
Bob
On Mon, 03 Nov 2014 00:39:24 +0100
Magnus Danielson magnus@rubidium.dyndns.org wrote:
It is worth knowing that active masers have a span for how the hydrogen
in-flux will make it oscillate or not. Too little or too high, and the
oscillation will die off. It may be one of the things to tune up if you
got an older one which needs a bit of good old Love, Tender and Care.
BTW: I always ment to ask, what makes H-Masers stop when there is
too much hydrogen? I can understand too little H causes the system
not having enough atoms to probe (or not getting enough energy into
the system for active masers), but i don't understand the "too many" case.
Attila Kinali
--
I pity people who can't find laughter or at least some bit of amusement in
the little doings of the day. I believe I could find something ridiculous
even in the saddest moment, if necessary. It has nothing to do with being
superficial. It's a matter of joy in life.
-- Sophie Scholl
On Sun, 02 Nov 2014 21:49:34 -0500
Chuck Harris cfharris@erols.com wrote:
They cleaned the vessel very well first with acetone and second,
probably a little distilled water to etch the glass slightly,
Distilled water etches glass? Really?
Attila Kinali
--
I pity people who can't find laughter or at least some bit of amusement in
the little doings of the day. I believe I could find something ridiculous
even in the saddest moment, if necessary. It has nothing to do with being
superficial. It's a matter of joy in life.
-- Sophie Scholl
Yes, really.
Ever see a double pane insulated glass door that looks white
and frosted on the inside? That is due to water vapor that
found its way between the panes, and condensed. Because the
inside glass is about as clean and free of dirt (minerals) as
the manufacturer could make it, the condensed (distilled) water
leaches out silicon, etching the glass.
Nature abhors a vacuum.
In the case of putting a teflon coating inside of the bottle,
you want the sides of the bottle to have lots of nooks and
crannies (at a molecular level) for the teflon to mechanically
grip onto... So, it helps to etch it a little bit. HF will do
the job very quickly, but if you have a source of well polished
distilled/dionized water, you can etch it that way as well...
it just takes a little longer.
-Chuck Harris
Attila Kinali wrote:
On Sun, 02 Nov 2014 21:49:34 -0500
Chuck Harris cfharris@erols.com wrote:
They cleaned the vessel very well first with acetone and second,
probably a little distilled water to etch the glass slightly,
Distilled water etches glass? Really?
Attila Kinali
I would presume the usual reason is you want enough hydrogen
to resonate at the desired microwave frequency, but not so much
that you wreck the Q (spread the line width) with excess collisions.
-Chuck Harris
Attila Kinali wrote:
On Mon, 03 Nov 2014 00:39:24 +0100
Magnus Danielson magnus@rubidium.dyndns.org wrote:
It is worth knowing that active masers have a span for how the hydrogen
in-flux will make it oscillate or not. Too little or too high, and the
oscillation will die off. It may be one of the things to tune up if you
got an older one which needs a bit of good old Love, Tender and Care.
BTW: I always ment to ask, what makes H-Masers stop when there is
too much hydrogen? I can understand too little H causes the system
not having enough atoms to probe (or not getting enough energy into
the system for active masers), but i don't understand the "too many" case.
Attila Kinali