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Homework Help: Nuclear reaction cross section

  1. Sep 15, 2008 #1
    Suppose we consider a beam of neutrons incident upon a thin target with an intensity of 10^12 neutrons/(cm^2.s). Suppose further that the total cross section for the nuclei in this target is 4 b. Using this information, determine how long one would have to wait, on the average, for a given nucleus in the target to suffer a neutron interaction.


    The way i approached this is to get a rate from Intensity*cross section = rate
    this gives

    10^12 neutrons/(cm^2 sec) * 4.0 × 10^-24 cm^2 = 4 × 10-12 s^-1

    Then taking 1/rate should give the length of time...but this gives an extraordinarily long time of course which leads me to believe something is wrong?
    how should this be approached
     
  2. jcsd
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