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Nuetron activation

  1. Nov 27, 2013 #1
    Co-60 is produced from Co-50 through neutron activation. Neutron flux 10^18 nuetrons/(s*m^2). cross section is 20 barns and the mass of Co-50 40mg. How many Co-60 are produced in one week?

    My attempt:
    I multiplied the flux by the seconds in one week and by 20 barns in m^2 and got 0.0122 neutrons. Then found how many atoms are in the 40mg of CO-50 which was 4.08598x10^20 atoms. Then i multiplied the amount of atoms by the number of neutrons in Co-59 and add to the number of neutrons found by the flux and then divided by 33 neutrons for how many are in C0-60. This gave me the number of nuclei of Co-60 found which was not the right answer.
  2. jcsd
  3. Nov 27, 2013 #2


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    I think C-50 should be C-59 everywhere.

    Careful, the unit is more like "neutrons per atom".

    The reaction involves the whole nucleus, and the cross-section is "per nucleus".

    Again, why?
  4. Nov 27, 2013 #3
    I assumed that if i had the total number of neutrons of the CO-59 and added it to the number of neutrons that came from the flux, i could find the total number of Co-60 neutrons and then find how many nuclei from that.
  5. Nov 27, 2013 #4


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    Staff: Mentor

    You don't have the total number of neutrons in the beam, and you don't need it.
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