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Prime candidates are even numbered elements with an odd number of neutrons. This is because subtracting or adding a neutron produces an even-even nucleus, and these tend to be stable. The reactions that yield the most energy would use a neutron source where the neutron is only bound loosely. Here is a table with some isotopes and the binding energy of the odd neutron (the lower the binding energy, the easier it is to remove):- Isotope Energy (MeV) ppm of the element in the Earth's crust D 2.2 ! Li7 7.25 13 ! Be9 1.573 1.5 C13 4.946 200 Mg25 7.331 32000 ! Si29 8.474 267700 ! Ca43 7.933 52900 ! Ti47 8.88 5400 ! Ti49 8.142 " ! Ge73 6.783 1.6 Se77 7.419 0.05 Sr87 8.428 260 Zr91 7.194 100 Mo95 7.369 1 Mo97 6.821 " Pd105 7.094 0.001 Cd111 6.976 0.098 Sn117 6.943 2.5 Sn119 6.483 " Ba135 6.973 250 Ba137 6.90 " The most useful isotopes are likely to be those of low atomic number, high abundance, and reasonably large isotopic percentage of the element in question. These have been indicated with an "!". In particular, Mg25 may be an opportunity that has been missed so far. It is interesting both because of it's abundance, and because of the neutron binding energy comparable to that of Lithium. Possible interesting reaction:- 25Mg + 25Mg => 26Mg + 24Mg + 3.763 MeV Furthermore the energy is divided over two nuclei of almost equal mass, hence each gets about half (1.9 MeV), so this could be a very clean reaction. Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
