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Defect production / neutron radiation

  1. Oct 27, 2014 #1
    I have been told, that neutron radiation, rather than electron or proton radiation, is used to produce defects in solids. And the reason is that electron has a small mass comparing to the nucleus of an exerted atom, thus can not really displace it, and concerning protons, that most of their energy goes to the electron excitation.

    1. Why neutrons don't excite electrons, and why most of protons energy goes to electron excitation rather than atom displacement?

    2. Do I understand correctly, that excitation of electron due to the massive particle is a result of massive collision of it with some incident particle, thus transferring kinetic energy from this particle to the electron internal energy?

    Thank you.
     
    Last edited: Oct 27, 2014
  2. jcsd
  3. Nov 1, 2014 #2
    Thanks for the post! Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
     
  4. Nov 2, 2014 #3
    Neutrons don't carry an electric charge. Therefore they interact weakly (only through spin) with electrons. Neutron diffraction experiments typically are sensitive only to the positions of the nuclei, and the magnetic structure of the electrons.

    Protons and electrons, on the other hand, are charged and therefore interact strongly with the electrons in the solid.

    The electric field of the nucleus in the solid is strongly screened by the electrons, which are distributed throughout the solid. For low energy electrons and protons, the interaction is mostly with the electrons. For high energy charged particles, interactions with the nucleus are important, as shown in the famous Rutherford gold foil experiment.

    http://en.wikipedia.org/wiki/Geiger–Marsden_experiment

    It is not quite clear to me how this is related to the creation of defects. Neutrons can be used in isolated cases to dope a solid, essentially by inducing a nuclear reaction like Si + n --> P + e-

    http://www.frm2.tum.de/en/technik/irradiation-equipment/silicon-doping-installation/index.html [Broken]
     
    Last edited by a moderator: May 7, 2017
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