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Artificially Induced subcritical Heavy Ion fission

  1. Feb 22, 2010 #1
    This is an idea I had and felt it worth publishing. The reason fusion is so difficult is because the particles are so light, small, and have difficulty overcoming the coulomb barrier. Well I got to thinking and noticed that it'd be a lot easier to get heavy nuclei to fuse, but naturally they'd be incredibly unstable. Then it hit me, incredible instablility is a GREAT thing! When two heavy nuclei collide and neutrons/protons join or fall off, an unstable ion is inevitably created. Think about it, each atom on the periodic table, including isotopes, is usually stable for the most part, even radioactive elements(stable in terms that they dont randomly explode into several different atoms). When two lead atoms for instance are ionized and accelerated towards each other, the inertia alone would be enough to overcome the coulomb forces, not to mention increased chance of impact due to size. While the collision products are almost completely incalculable, the resulting instability will inevitably result in fission to more stable elements. What's even better is that even these reaction products, radioactive or not, can be reused and accelerated again into something like a lead atom.

    An example of how this works would be to think of a rock atop a tall cliff. The rock at this point has a lot of potential energy, but it isn't near the cliff and thus no energy will be produced. The process I speak of is equivalent to pushing the rock to the edge, increasing the chances of falling and thus a much higher chance to reach a ground state(releasing energy in the process). Lead is a stable atom, but only slightly so, a couple more protons or neutrons and it becomes unstable and fissions. I'm not sure what sort of radiations or reaction products it'd give off, but I do have an experimental setup in mind to make it happen. I'd like to see some responses to this topic, and maybe a reason why I don't see ideas like this anywhere else. Thanks for reading.


    P.S. If this didn't make sense please say something. I'm not great at explaining things =P
    Last edited: Feb 23, 2010
  2. jcsd
  3. Feb 24, 2010 #2
    This sounds to me very much the basic idea used to produce superheavy elements in various accelerators worldwide. For example to produce element 114, plutonium-242 atoms are bombarded with calcium-48 ions. The cross section for this reaction (probability of a reaction) is however very small and it takes a six weeks experiment to produce a single atom of element 114. For more information see the section on superheavy elements in http://www.nucleonica.net/poster.aspx
    Last edited by a moderator: Apr 24, 2017
  4. Feb 24, 2010 #3
    The difference is that the scientists doing those experiments are specifically trying to create one element, and even one proton missing will completely ruin the whole collision. (thus it takes weeks) The purpose of my idea is to purposely induce an unstable isotope through partial fusion. The odds of a stable isotope formed through fusions of heavy atoms is almost non-existent, that's another reason why it takes so long to get the specified atom. Anyway, when the unstable isotope inevitably forms, no energy is released, it's only when the instability actually fissions the atom that it releases the energy. I hope this kinda cleared things up, and please tell me what you think, I'm just bouncing ideas around.

  5. Feb 26, 2010 #4
    I understand your idea, but I don't think the numbers are practical. The methods we have for producing fast moving ions are very inefficient (converting from electrical energy to kinetic energy). I don't think that you would ever get sufficient energy out to produce net usable energy.

    Accelerators have been used to produce fusion in light element, the issue has always been that it take more usable energy to make it happen than can be extracted from the reaction.

    You could run the numbers to figure out the required minimum collision energies for heavy nuclei to over come the coulomb barrier. That would give a starting point to see what kind of acceleration device you would need to achieve those energies. Then you could look at the efficiency of those systems.
  6. Feb 26, 2010 #5


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    Actually, it is rather difficult to 'fission' elements below Th. In most cases, one will get a spallation reaction, and usually more energy is put in per reaction than obtained form the subsequent reaction. Fission systems work because of the neutrons which do not need energy input from an accelerator.
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