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Uranium deposit -- location techniques question

  1. Jul 7, 2017 #1
    I read that one can find Uranium for its gamma radiation hence gamma can travel through even dense and thick stuff, but natural Uranium that hasn't gone through fission doesn't emit gamma correct, so I was reading how they find Uranium reserves underground and it says that they use a alpha emitter combined with beryllium which then undergoes spallation and produces neutrons, then it is said that they use these neutrons to see whether there is Uranium in the ground because if there is they can detect some delayed neutrons coming back from the induced fission of the neutrons that came out from the beryllium checking device.
    Here is what I don't quite get, I suppose it is rarely when Uranium deposits simply lie close to ground, under grass or right on top of soil, I assume they are mostly rather deep below ground, now how do these neutrons penetrate deep enough to strike the U deposits and even get back some delayed fission neutrons, how come these neutrons simply don't get lost or scattered or else while they are traveling through the layers of rock and soil and other stuff in the ground?
    Or do they "finetune" the neutron energies so that they don't interact with other elements but only either U 235 or U 2
  2. jcsd
  3. Jul 7, 2017 #2


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    Neutron activation analysis is an active technique. One can use an (α,n) source, or a fusion-based d+t source of neutrons. The neutrons can be thermalized with something like water or polyethylene. U-235 has a higher cross-section for thermal neutrons, so thermal neutrons would react with U-235. One would normally bore a tunnel, or take a coring sample and assay the rock above ground. The technique is used for exploring geological formations bearing minerals.

    U deposits also incorporate beta- and gamma-emitting daughter products, which are detectable by Geiger/proportional counters. This would be a passive method.

    Some deposits are near the surface, but many are not. Where the uranium is deposited has a lot to do with hydrogeology.

    Uranium is often found with other valuable elements, e.g., vanadium.
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