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Homework Help: Neutron beam hitting Uranium 238 foil

  1. Apr 5, 2009 #1
    1. The problem statement, all variables and given/known data[/b]
    A high energy beam of neutrons of intensity 10^6 s^-1 transverses a target of 238 U of thin foil whose density per unit area is 10^-1 kg m^-2. If the elastic and in elastic cross-sections are 1.4 and 2.0 b, respectively, calculate(a) the attenuation of the beam(b) the rate of elastic reactions and(C) the flux of elastically scattered neutrons 5 m from the target, averaged over all scattering angles.
  2. jcsd
  3. Apr 5, 2009 #2


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    Given the microscopic cross-section, σ, one should be able to determine the macroscopic cross-section, Σ, with knowledge of the atomic density, N or n.

    Then what is the formula for attentuation based on Σ?

    Note that one has σi (inelastic) and σe (elastic). Both contribute to attenuation, but parts b and c ask about elastically scattered neutrons.
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