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Homework Help: Triplet Production

  1. Jan 7, 2008 #1
    I have a question I am working on for which I need some help.

    "Using E^2 - p^2c^2 = invariant, calculate the thresholds for pair production and triplet production."

    This is what I have for pair production:

    Pair Production
    E^2 – p^2c^2 = invariant
    therefore, E > pc, for each electron produced, where E is the photon energy hv
    E > 2[m0 v c (excess KE of electron) + m0 c^2 (rest mass of an electron)] = 2 m0 c^2 , since v = 0 for minimum photon energy
    E > (2)(9.1E-31 kg)(2.998E8 m/s)2
    E > 1.636E-13 J / 1.602E-13 J/MeV
    E > 1.02 MeV

    I am stuck on the triplet production. I found one reference that has the KE transferred to the stationary electron with the excess photon momentum = me-c^2, m sub e-

    Any help or critique would be appreciated. Thanks.
    Last edited: Jan 7, 2008
  2. jcsd
  3. Jan 8, 2008 #2


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    what have you tried? It is hard to give you critique when dont show what you have tried.
  4. Jan 8, 2008 #3
    I was speaking of critiquing pair production and maybe and idea where to start on the triplet. I think I will start on conservation of energy and post tonight.

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