Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Interpretation of Cross Section of p,n reaction mb or mb/MeV

  1. Nov 29, 2013 #1
    Dear Forum :

    I'm reading a cross section data of 20MeV proton + 16O reaction from ICRU 63.
    ( as attachment and link http://ppt.cc/qf-9 )
    The total cross setion of (p,n) reaction is 4.372mb
    However, the cross section of emitting neutron of energy between 0 to 1.5MeV is 0.91 mb / MeV.
    The cross section of emitting neutron between 1.5 to 2.5 MeV is 2.3 mb / MeV .

    But how can the cross section be written as 0.91 or 2.3 mb / MeV, because as 20 MeV proton, it would give a
    cross section of 18.2 and 46 mb, which is larger than the total (p,n) reaction
    Is it the correct or just the traditional way to present the cross section as mb / MeV ?
     

    Attached Files:

  2. jcsd
  3. Nov 29, 2013 #2

    mfb

    User Avatar
    2017 Award

    Staff: Mentor

    I think the MeV refers to the neutron energy.
    So you have (1.5*0.91)mb for a neutron between 0 and 1.5 MeV (is there a factor 10 missing?).
     
  4. Nov 29, 2013 #3
    thanks mfb,

    (1.5*0.91)mb for a neutron between 0 and 1.5 MeV should be correct.
    Summation of (1.5*0.91) + 2.3 + 0.75 equals to the total (p,n) reaction cross section.
    BTW, which part of factor 10 missing?
     
  5. Nov 29, 2013 #4

    mfb

    User Avatar
    2017 Award

    Staff: Mentor

    Oh, I did not see the "-1". 0.91 is fine.
     
  6. Nov 29, 2013 #5
    Thanks a lot
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook