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I have a problem with units

  1. Sep 17, 2007 #1
    I have a problem with units....

    I have been looking at energy loss of muons in matter (from both ionizations and radition processes like bremsstrahlung). I have used an equation for the mean energy loss (for a muon of specified energy in a specified material) which gives an answer in units of g/cm^2/MeV. I am ok with converting this to cm/MeV I think (just divide by the density), but my problem is what does the 'per MeV' bit mean?

    I have 50GeV muons going into concrete and from what I have read the mean range is ~45m. The equation I am using gives me an answer of 6.58cm/MeV (or 16.44g/cm^2/MeV) and I'm puzzling over how this gets converted into 45m.

    Any help?
  2. jcsd
  3. Sep 17, 2007 #2


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    MeV is million electron volts. Electron volts is the energy to raise a electron of charge through 1 volt and so 1ev= 1.6E-19J ( ie the charge on the electron in Coloumbs)
    It is a more convenient sized unit of energy and mass when dealing with particles.
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