Fusors and p-B11

TallDave · Post by **TallDave** » Wed Oct 01, 2008 3:14 pm

Int,

Depends how much fusion you want, and how much you're willing to spend. You'll never get anyhere near Q, of course. It might be possible to get measurable p-B11 fusions out of a fusor before it melts/shorts/ablates/etc into nonfunctionality, but I don't think anyone's done it yet, which suggests it's not easy.

Keep in mind, if I'm understanding the fusor design correctly, the inner grid not only has to hold a huge negative charge but also gets hit by some percentage of those extremely energetic p and B11 ions.

Has anyone ever run a fusor at 200 kEv drive? Not sure what the technical challenges are there.

MSimon · Post by **MSimon** » Wed Oct 01, 2008 3:22 pm

Munchausen wrote:
The polywell will face similar trade-offs but may come to a different conclusion. In particular, if the thermal load is (as is the dream) primarily bremsstrahlung radiation and alpha particles, the erosion process will be very different from that due to the high-power, low-temperature plasma in a tokamak divertor.

This sounds like expensive and time consuming technical development? Isnt it better to aim for an esier fuel (D-Doch D-T) and steam cycle energy extraction in the first place? If the polywell contraption should show any signs of life.

The trade off is protecting the superconductors from high neutron flux. I have a proposed design which might be workable (water cooling/moderation B10 neutron absorption) but it will increase the reactor volume some. Also the neutron flux will deposit about 2.8 MeV per neutron absorbed by the B10. That is in the same ball park as alpha impingement.

At the 100 MW level two paths may be useful (D-D and pB11) to get to a "final" reactor design. The engineering problems are significantly different once you get past the basics.

MSimon · Post by **MSimon** » Wed Oct 01, 2008 3:27 pm

TallDave wrote:Int,

Depends how much fusion you want. You'll never get anyhere near Q, of course. It might be possible to get measurable p-B11 fusions out of a fusor before it melts/shorts/etc, but I don't think anyone's done it yet, which suggests it's not easy.

Has anyone ever run a fusor at 200 kEv drive? Not sure what the technical challenges are there.

If you go for the resonance peak 70KV should be adequate (includes well losses). Well within current high end fusor designs.

No need to run a fusor til it melts to get experimental results.

TallDave · Post by **TallDave** » Wed Oct 01, 2008 3:45 pm

Resonance certainly wouldn't hurt. This is the POPS compression we're talking about here, right? How difficult/expensive is that?

I do wonder if current fusor grids would have a problem with the heavier B11 ions hitting them vs. the usual D or T.

MSimon · Post by **MSimon** » Wed Oct 01, 2008 4:22 pm

TallDave wrote:Resonance certainly wouldn't hurt. This is the POPS compression we're talking about here, right? How difficult/expensive is that?

I do wonder if current fusor grids would have a problem with the heavier B11 ions hitting them vs. the usual D or T.

POPS compression would add a few hundred dollars at hobby levels.

The big problem with pB11 experiments is alpha detectors.

Simon

TallDave · Post by **TallDave** » Wed Oct 01, 2008 5:19 pm

Heh, I guess maybe that's one reason no one's done this: there are certainly easier ways to get a few alphas.

classicpenny · Post by **classicpenny** » Wed Oct 01, 2008 5:47 pm

MSimon wrote:
The big problem with pB11 experiments is alpha detectors.

Simon

I did not realize this was a problem. I guess I was assuming that we would look for helium in the spectra of the gases removed from the chamber after a trial.

Bill Flint

MSimon · Post by **MSimon** » Thu Oct 02, 2008 4:50 am

classicpenny wrote:
MSimon wrote:
The big problem with pB11 experiments is alpha detectors.

Simon
I did not realize this was a problem. I guess I was assuming that we would look for helium in the spectra of the gases removed from the chamber after a trial.

Bill Flint

To be sure of fusion and not trace gases or side reactions you want to look for alphas of a specific energy.

So the detectors will need to be in the vacuum.