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Revision as of 22:22, 13 March 2005
Muon-catalyzed fusion is a process that allows fusion at room temperature. Although it can be produced reliably with the right equipment and has been much studied, it does not currently provide anywhere close to breakeven energy. It is sometimes known as cold fusion; this term, however, is no longer often used, as it can create confusion with other scientifically unestablished forms of room-temperature fusion.
In muon-catalyzed fusion, deuterium and tritium nuclei form atoms with muons, which are essentially heavy electrons. The muons orbit very close to the nuclei, shielding the positive charge of the nuclei so the nuclei can move close enough to fuse.
Andrei Sakharov and F. C. Frank predicted the effect on theoretical grounds before 1950.
The practical problem with muon-catalyzed fusion is that muons are unstable (decaying in two microseconds); hence, there needs to be some cheap means of producing muons, and the muons so produced must be arranged to catalyze as many reactions as possible before decaying. As J.D. Jackson recognized in his seminal 1957 paper, "Catalysis of Nuclear Reactions between Hydrogen Isotopes by Mesons," Physical Review, Vol. 106, No. 2, April 15, 1957, the real problem with muon-catalyzed fusion is that there is a non-vanishing probability (about 1%, actually) that the muon would "stick" to the alpha particle (a Helium-4 nucleus) that results from the deuterium and tritium fusion, removing the muon from the catalysis process. Even if the muon were absolutely stable, it could only catalyze, on average about 100 fusions before sticking, about one fifth the number needed to produce breakeven energy.
Mesons," Physical Review, Vol. 106, No. 2, April 15, 1957, the real problem with muon-catalyzed fusion is that there is a non-vanishing probability (about 1%, actually) that the muon would "stick" to the In 1999, Takahiro Matsumoto reported in JP Patent No. 3073741 that the alpha-sticking probability as low as 0.03% was achieved by injecting muons to porous silicon with a deuterium and tritium terminated surface. According to the patent, a muon can catalyze more than 1000 deuterium-tritium fusions on the porous silicon surface at room temperature, and more than 1500 fusions at 500K.
References
- Rafelski, Johann and Steven E. Jones (1987). "Cold Nuclear Fusion". Scientific American, v. 257 #1, pp. 84–89.
See also
nuclear fusion, Antimatter catalyzed nuclear pulse propulsion
External links
- JP Patent No. 3073741 (Japanese)
- English Abstract of Patent