Joseph Chikva wrote:
dkfenger wrote:I think a lower bound on muon production in the 400MeV range seems reasonable.
Reasonable but impossible.
And why I should concider deuterium cycle?
50-100 D-D events produce about 200-400 MeV
Actually, D-D reactions can produce more energy than the ~ 3 MeV per D-D fusion. I'm skeptical of the 40 MeV number, but still a lot more energy than 3 MeV. If you take 6 deuteriums, fuse 4 of them, you get one T, one He3 and ~ 6 MeV. Then fuse the last two D with the T and He3 and you get ~ 20 MeV and 12 MeV (estimates from memory). This adds up to ~ 38 MeV, but remember that this needs 4 separate fusion events to obtain. The average per fusion would be ~ 9-10 MeV/ fusion. Higher yields would come from burning D-T directly, but then you have to produce the tritium first.
Also note that the tritum and He3 would leave have to be moderated (slowed) befor reacting further (we are talking about liquid hydrogen temperatures). This would eat through the Muon aviable life time. If one muon could catalyze 100 reactions before it decayed, then it could at best catalyze 25 of the above chain reactions (100/4). This would dampen any advantage. One chain completed with ~ 35 to 40 MeV yield vs 4 D-D fusions with ~ 12 MeV. There is a possible advantage, but much less than was suggested, even without any time penalties that I suspect would be significant.
The reason liquid hydrogen temperatures are needed because high densities are needed to get usefull fusion rates with the short lived muons.
I supose you could approach this with a super DPF machine if you could synchronize everything, though the pinch (high density) only lasts for a fraction of a microsecond. Though with the time necessary for the creation and transfer of the muons, this time may be reasonable. But if it takes a significant fraction of the muons lifetime to get into place in the fusion reaction space, the possible number of fusions per muon goes down.
Creating muons in a particle accelerator can and has been done. But we are talking about a few . Perhaps a few dozen or a few million muons per second may be produced in the accelerator.
To produce ~ 1 MW, you need ~ 10^18 fusions per second . This divided by 100 fusions per muon means you would need ~ 10^16 surviving muons per second output from the particle accelerator. This would probably require a CERN on steroids accelerator*. That is why I said the total system size would even put ITER to shame. If there is some possibility of success you might need to scale up considerably to break even from a financial perspective. You might have a plant that produces 10-100 GW and a final size that would put a whole farm of ITER tokamaks to shame.
Of course if you have a secrete recipe for making muons in situ in the fusion chamber cheaply and in great profusion, then the story is different. Maybe Rossi should be put on the project!
*Actually a much smaller accelerator would be needed to produce a few muons, but it is not a question of making muons, but of making muons in relatively tremendously huge quantities. And the efficiencies may be much lower than stated. Making muons at one percent efficiency (energy in vs muon energy out) may be optimistic.
To error is human... and I'm very human.