Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: Cylindrical or Axial flow IEC - Good Reference
Date: Jan 20, 10:59 pm
Poster: Blair Bromley

On Jan 20, 10:59 pm, Blair Bromley wrote:

>>Sure, this seems easier, but from the paper, I think it takes a bunch more voltage to get significant neutron production. Is the goal here to make an easy, simple, cheap thing that does fusion or a neutron source (in which case the spherical geometry is probably better), or to produce neutrons period or what..
>>If all you want to do is make neutrons using fusion, an electrostatic potential drop accelerator producing 200 keV deuterons hitting a deuterium target (heavy water ice?) is probably the easiest route.

Actually, this has been done, except that the
target is usually a metal hydride that is heavily
doped with tritium. These systems are pretty
handy for neutron production, but the drawback
is that you have to replace the target and
you must operate at the higher voltages to get
the necessary ion penetration into the target,
along with the higher cross sections.

IEC devices, if successful, could supercede
these AST (accelerator solid target) neutron
sources in neutron production at a lower

>I think we are missing the point about axial flow. What I was trying to say was that axial flow IEC's like the one at U of I seem easier to make and seem to have the potential to be focused with just some minor modifications to the current scheme.
>I don't know if anyone has noticed but in an axial flow IEC that puts you less than an inch away from the reaction zone, pretty convenient for research purposes. Try that in a spherical device.
>Counting cylindrical IEC's out of the fusion game is just as foolish as counting any other IEC out of the fusion game. Axial flow seems to have the potential to focus the ions better than a spherical IEC.
>As for neutron counts, if I'm not wrong Blair stated that the U of I unit could reach pretty high neutron rates, high enough to impress Richard Hull. If we are trying to do better than the pros or break even than good luck, I doubt any amateur will ever do that.
>Either way, I still think Axial flow IEC's have a lot of potential for some real fun.
From an engineering point of view, the axial-cylindrical IEC is much easier to construct, and hence the cost for doing a series of experimental studies in which you try a variety of different electrode designs, spacings, diameters, etc. will be much more economical. Whether or not the axial-cylindrical device is suitable for approaching a break-even fusion device remains to be seen.

One reference that I came across, almost by accident, presents a summary of some excellent research done on a high-voltage glow-discharge
device operating with deuterium back in 1961. I think it would be excellent if someone who has the resources and ambition to repeat and extend the experimental work of this researcher. It appears to have some relevance to IEC technology.

Here's the reference:

G.W. McClure, "High Voltage Glow Discharges in D2 Gas Part I. Diagnostic Measurements, Physical Review, Volume 124, Number 4, November 15, 1961,
pp. 969-982.

You should be able to get this at any university physics library.

Best Regards,