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Elastic scattering of neutrons with hydrogen

  1. Feb 22, 2012 #1
    I am new to nuclear engg., i want to know the phenomenon of elastic scattering of neutrons.

    Resources available in the net suggest that in materials containing atoms of low atomic mass(hydrogen), neutrons of all energies can lose a significant fraction of their energy in a single elastic collision. As i understand, collision of a neutron, which has mass of 1, with a 1H nucleus could result in the neutron losing virtually all of its energy in a single head-on collision.

    Here i want to know what happens to hydrogen which absorbs neutron energy. please clarify.
    If there are any related links pls let me know..

    Thank you.
  2. jcsd
  3. Feb 22, 2012 #2


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    If a particle strikes another particle of approximately the same mass, then the target particle could absorb most of the energy (kinetic) and momentum and move off. In the case of a proton (nucleus of a hydrogen atom), it would simple travel and ionize the atoms in the medium through which it travels.

    An example of elastic collision between objects of the same or similar mass.

    If a proton combines with (absorbs) a neutron, it forms a deuteron (the nucleus of a deuterium atom).

    It would be rare to have an exact head on collision. In most cases, it is a glancing collision, so the neutron loses some, but not all, energy.
  4. Feb 23, 2012 #3
    do protons also ionise atoms..?
    Thank you for ur quick reply Mr. Astronuc.
    Here i did not understand the following part of ur reply " In the case of a proton (nucleus of a hydrogen atom), it would simple travel and ionize the atoms in the medium through which it travels".
    As i know the ionisation process is by loss or gain of "electrons", do protons also ionise atoms..?
    If we take a unit mass of a hydrogenous material (polyethylene), and assume collision was with a particular hydrogen nucleus, would this travel in this mass and tries to ionise the atoms/molecules.?
  5. Feb 23, 2012 #4


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    Charged particles interact with atomic electrons in the medium through which they travel. Protons, alpha particles, beta particles (electrons and positrons) cause significant ionization. Photons (X-rays and gamma rays) also ionize atoms through the Compton (scattering) and photoelectric effects.

    At some point, the proton would sufficiently slow down and recombine with an electron to form a hydrogen atom. It could become part of an organic molecule or a hydride in a metal, or part of a hydroxyl ion if it enounters an oxygen atom.

    In most cases, ions recombine with electrons.
  6. Feb 23, 2012 #5
    Thank you Mr. Astronuc,

    discussion with you was great and has cleared lot of my doubts.
    Santhosh Malkapur
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