If you take a large amount of ultracold neutrons and confine them in a bottle would they then decay into protons and then fuse because they are so tightly condensed that the protons, once neutrons, bypass the coulomb barrier?
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one would have to do actual calculations, no? actual temperature , pressure, density etc. https://en.wikipedia.org/wiki/Nuclear_binding_energy#Nuclear_binding_energy_curvearios After all one does have a number of bound states – anna v Jun 22 '19 at 08:34
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The neutrons would decay alright, with a half life of about 10.5 mins. but the resulting mixture of protons and neutrons wouldn't fuse. Cold fusion was discredited about 25 years ago. The easiest way to get a flask or a bottle full of neutrons is to fill the bottle with liquified tritium or a mixture of tritium and deuterium. This is what the Americans did at Elugulab Island in the Eniwetok atoll, Marshal Islands, in 1952. A powerful refrigerator was needed to freeze and liquefy the hydrogen isotopes, but a fission bomb was needed to create the temperature at which they would fuse. The resulting multi-megaton explosion wiped the island off the map, but it certainly wasn't a case of cold fusion. This first thermonuclear explosion wasn't a bomb, because no aeroplane could carry it, so it was called a 'device'.
Michael Walsby
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though cold fusion has a different meaning now https://en.wikipedia.org/wiki/Cold_fusion – anna v Jun 22 '19 at 10:34
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"but the resulting mixture of protons and neutrons wouldn't fuse." Nonsense. This simply isn't what is meant by cold fusion. Further we regularly put free neutrons in the presence of matter and they do fuse. This behavior is part of the working mechanism of anti-neutrino detectors. – dmckee --- ex-moderator kitten Jun 22 '19 at 15:19
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It may not be what's meant by cold fusion,but it is cold fusion nevertheless. Maybe Pons and Fleischman should have tried it. Are you sure your anti-neutrinos don't come from the decay of neutrons? – Michael Walsby Jun 22 '19 at 15:34
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Yes, anti-neutrinos are generated in beta decay. Then we detect them when they generate so-called "inverse beta decay" events. And part of that detection scheme uses the fact that the free neutrons generated by the inverse beta decay on hydrogen in the target subsequently fuse with other nuclei in the detector. In KamLAND most such fusions were with protons and the time-scale for neutron capture was a couple hundred microseconds. – dmckee --- ex-moderator kitten Jun 22 '19 at 15:58
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And Pons and Fleischman didn't bother with free neutron-proton fusion for the same reason that everybody else ignores it: it is easy to do, but in the absence of some reliable natural source of free neutrons its costs you energy in the long run.. – dmckee --- ex-moderator kitten Jun 22 '19 at 16:02
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Cold fusion is about the fusion of 2 positively charged nuclei, repulsing each other. Protons regularly fuse with neutrons in light water nuclear reactors, what is the reason they need enriched uranium, in contrary to heavy water reactors, where fusion of deuterons with neutrons is much less probable. – Poutnik Jun 24 '19 at 05:21