by Doug Coulter » Fri Apr 08, 2011 11:51 am
Who knows? I sort of doubt it, but...
Here's why I think that. It's long mean free path at low pressures. With the uWave ion source, you get an extremely long path, due to the cyclotron effect on the electrons whirling around in there till they hit something -- could be miles long paths for them. Whereas with a source (I'd pick an alpha source myself) you've only got the tank-size worth of path, and at low pressures, not many gas molecules to hit. I just don't think you get enough current to run a fusor easily that way. Probably enough for a beam on target device, which uses a lot less. Even for that, I'd pick the uWave source if I could get it integrated. Due to other limitations, right now my next BOT thing will need split supplies, and floating a magnetron 60kv off ground doesn't sound real practical...
But those limits won't obtain later on, we have a nifty new supply on the way supposedly (1 ma, 160kv, zowie). The design in the Phillips chapter I keep linking gets it done with just a penning source at reasonable pressures for a sealed off borehole tube, pretty simple if not completely ideal.
It's probably worth a test, however. I have a bunch of hot alpha sources (alphas plow the gas much better than other things), and I could try it on some fusor once I have one really stable, and see if it lets me stay "lit" to lower pressures. The big system is in fine tune just now, so perhaps as soon as I get some nice baseline data into my database, I can shove those sources in there and compare. Till then, I'm not opening that door!
But even a pretty hot source is very low "current". Even a whole curie is only 107 decays/second, which sounds big until you realize that an amp second of electrons is 1019 or so. Even assuming multiple ionizations per decay....not that nifty. It could be you only need a little to trigger a process that creates more (like a fusor) however, and this would be a lot more reliable than cosmic rays, which is why they do that in the first place. Heck, I've got one Bill found that has Ra in it, and that sucker sets off geiger counters from across the room. Bill says he can get more, and I might just encourage that, as they are also useful as is -- they were main switches in a radar, not T/R, but the switch for main magnetron power, and they trigger at 2kv -- a few in series might be really nice for a marx generator, a tesla coil, or other pulsed things.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.