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Re: RF ion source, modified, with deuterium (a couple "glassblowing" pics)

Posted: Sun Nov 09, 2008 12:06 am
by Starfire

Re: RF ion source, modified, with deuterium (a couple "glassblowing" pics)

Posted: Sun Nov 09, 2008 2:16 am
by Steven Sesselmann
Carl,

I like that oxy generator..

By the way, are you getting a brown build up inside the glass tubes after prolonged use?

If so, will it affect the function of the source?

Steven

Re: RF ion source, modified, with deuterium (a couple "glassblowing" pics)

Posted: Mon Nov 10, 2008 5:24 pm
by David Rosignoli
Carl,

Nice work. Did you find yourself either pre-heating or post-heating the glass to prevent stress fractures? How did you rotate the glass - by hand? cool stuff.
Dave

Re: RF ion source, modified, with deuterium

Posted: Tue Sep 21, 2010 12:54 pm
by chab
Carl-

Where did you find a 19 mm test tube, either quartz or pyrex? All I can find is plastic. I am trying to dup your gun, with mods, and need only the tube, but I am at a loss.

Thanks,

Charlie Habekost

Re: RF ion source, modified, with deuterium

Posted: Tue Sep 21, 2010 1:30 pm
by Doug Coulter
Boy, I want to see this baby in action, either fusor or beam-target. Great work *again*, Carl!
In my own work, I've found that getting this part right is key to the rest.

As Carl shows (y'all listen up) glass work is all about getting ready -- jigs, the right tools, and even a dry run before anything gets hot are key to success. That's not all that primitive a setup. We use graphite tooling too, and jig blocks, in our case made of that foamy-type kiln firebrick that has almost no thermal mass. Looks like we learned out of the same book.

I'm sure if Carl isn't annealing his work now, he will be at some point. Technique on that varies from just turning off the O2 and coating the piece with soot to using a heat treat oven, and it really helps, as does paying attention to tempcos of the things involved when using unlike materials. I like the oven if you have one available (I do, originally for heat treating steels) and Kohl's book gives all the times and temps for a bunch of materials.

We built a simple thing that lets you put your work between crossed polarizers, with a light source, to see remaining stresses, and it's a great learning tool for anyone getting going. After awhile, you don't need it so much, but at first it's really a help -- and we just used cheapo polarizing film and a CCFL bulb (nice lines in the spectrum make the picture easier to see).

Electrode-less discharges like this are the best it gets in all our testing here. With ECR resonance, we can make ours run down to really low pressures (e-5 mbar and below) for work that wants that -- and need no differential pumping, a bonus. In ours, we let in the gas through the discharge, which may help it run at lower *tank* pressures, as there is some pressure drop between the discharge and the tank proper. Usable pressure differential tends to go up as mean free path does, as in moleclular flow, the gas has trouble getting out of the ion source unless it's ionized and the extractor pulls it out.

At this moment, the original RF source I posted on this forum many months back is still working, no noticeable degradation at all -- it ran yesterday at the flip of the power switch and has needed zero maintenance for a year of running some just about every day. It is the way to go, whatever the implementation details.

Looks like Carl has a real winner here.

Re: RF ion source, modified, with deuterium

Posted: Tue Sep 21, 2010 9:43 pm
by Carl Willis
Hi Charles,

I got my 19mm glass as standard-wall Pyrex tubing from a local scientific glassblower. It can also be ordered online.

19mm test tubes are not as common as some other sizes, but I still have a box of these from eBay auctions. 3/4" is very close...I can't remember if I have used those, but they should probably work.

Good luck, let me know how your ion source turns out.

-Carl

Re: RF ion source, modified, with deuterium

Posted: Wed Sep 22, 2010 1:13 am
by chab
Carl-

Thanks for the tip. I will get some 19 mm pyrez tube and blow a dome.

Charlie

Re: RF ion source, modified, with deuterium

Posted: Wed Feb 23, 2011 7:37 am
by steve_rb
Spend a few hours trying to do a rough 2D simulation of this Ion source to check how Siglo-2D works. results are attached. Seems at least it can show some sensable results.