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Re: An easier way to make a reactor? The K40

Posted: Tue Mar 13, 2012 3:20 pm
by Doug Browning
There is no attempt to do fusion here. You are calculating the wrong kind of cross section. The nuclei do not have to fuse. The nuclear barrier does not have to be fully breached. Just an impact. All those failed close encounters in fusion are just the ticket here. Two nuclei that bounce off each other are a failure in fusion. Fusion needs a direct head on collision. This has a much larger parameter space. If they just impart angular momentum from a glancing encounter here it may be a succes. You just need an interaction where the nuclei are deflected off course to impart angular momentum.

Re: An easier way to make a reactor? The K40

Posted: Tue Mar 13, 2012 3:38 pm
by Richard Hull
Most of the knowledgeable "flame throwers" you are relying on to hone your effort are staying out of this discussion.

Finally, you glibly note that all you have to do is separate the K40 from normal potassium. You are really a babe in the woods on this point. Statements like this tag the entire effort as one of futility. Nuff said.

Richard Hull

Re: An easier way to make a reactor? The K40

Posted: Tue Mar 13, 2012 4:03 pm
by Doug Browning
I didn't say laser isotope separation would be easy. It requires tuneable lasers operating on the gaseous phase and electrostatic separation of the ionized species. Uranium enrichment requires three separate lasers. Fortunately, K40/K39 has twice the isotopic effect of U238/U235, and we have cheap Erbium optical amplifiers available now. I already have quartz windows in the vacuum system. I did mention earlier that some investigation of the potassium system would be required (finding optical transitions of merit).

But if no one wants to participate in the discussion, I'll be happy to keep my ideas to myself. I thought the point of this forum was to put heads together to make useful progress and further the education of all the subscribers.

Re: An easier way to make a reactor? The K40

Posted: Tue Mar 13, 2012 4:25 pm
by Carl Willis
Richard's right, we probably do need to hang up this topic at this point.

My gauge for whether "useful progress" can be made in a discussion here is the extent to which the idea can reasonably be approached in practice in an amateur laboratory (my recent FAQ for this forum makes that point). A great number of far-flung schemes come up here. There has to be some standard for keeping the stuff grounded in reality and relevant to an amateur audience. Enriching K-40 and doing something nuclear with it afterwards strikes me as the longest of long shots for an avocational project, so let's only revisit this thread if there is a practical direction WE can take with it.


Re: An easier way to make a reactor? The K40

Posted: Tue Mar 13, 2012 4:37 pm
by Doug Browning
OK, I can take the hint.
Not trying to be S-A about it, but I do seem to recall a considerable amount of separated hydrogen isotopes being mentioned here already. No one has replied to my question of whether there are any isotope supply sources out there, so I cannot say whether K40 can be bought off the shelf. A small sputtering source added to a fusor is all that would be required in that case to try this in a fusor. Separation by electrolysis or electrophoresis would likely be impractical or at least beyond the realm of average patience. One long shot might be some utilization of the differential pumping capacity of a turbo on a gaseous form. Hmm, actually electrophoresis of KF looks like it might be workable and cheap (single isotope of F19). Just need a very uniform gel diffusion media to keep it coherent until the spots separate. Forget the lasers. Solved.

Re: An easier way to make a reactor? The K40

Posted: Tue Mar 13, 2012 5:52 pm
by John Futter
Next time I have a K beam up in our implanter I'll try to place K40 near the surface @ 10kV then turn up the energy to 40kV and whack those already implanted K40's with further K40's
I fear no resulting energy

Re: An easier way to make a reactor? The K40

Posted: Tue Mar 13, 2012 6:13 pm
by Doug Browning
That would be excellent!
Either it swims or it sinks.
Gamma/Beta ray detector and shielding?

There must be some ballpark calc'd estimate that can be done to estimate a minimum interaction energy. I have to think about it some more. Maybe an estimate of how much max. angular momentum the departing electron or positron could remove if emitted at the periphery of the nucleus. Problem is that, that may just give the amount over what is stable as the end product, and what is needed is the delta from ground state to the unstable level.

Gets further complicated when including the atomic electrons, but thats probably just a loss mechanism plus a small adjustment to any nuclear barrier, maybe just ignore them plus add some 10 Kev fudge factor or so. Although the electron cloud may absorb a large part of the angular momentum from a near miss collision, if it doesn't get expelled altogether. Cross section likely has to have the nuclei pass at least within the inner electron orbital radius, probably more like a tenth of that, maybe as bad as 1/137 ot that.

By the way, where can I get some K40? I may have to do some electrophoresis to get it.

late edit:
I see listed on Wikipedia a metastable K40 state with 336 nSec lifetime:
40mK 1643.639 keV 336 ns
That 1643.639 keV figure sounds very worrisome! But that also seems to be around the same keV level as the decay products, so maybe this is not so informative. It also gives spin states for K40 and 40mK which are -4 and 0 respectively. That may be a useful clue. But it may also just be representative of what the decay products took away. I'll have to see what semi-classical energy a -4 spin state would represent over a 0 state.

Re: An easier way to make a reactor? The K40

Posted: Tue Mar 13, 2012 8:04 pm
by Carl Willis
Electrophoresis? This is making less and less sense the more I read.

John can run his implanter with potassium (if he finds that to be a rewarding use of his resources) and in principle there might be something interesting to come of it. But the idea that something nuclear might happen under the circumstances has as much basis in mainstream theory or observation as a claim that yodeling attracts unicorns.

For now, we are going to close the thread...