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Homework Help: Nuclear Photo Reaction + Threshold Energy

  1. Apr 12, 2012 #1
    1. The problem statement, all variables and given/known data

    I am given a scenario where a photon and a nuclei interact and create two daughter nuclei/particles. I won't bother with the full scenario as it would be nice to solve this generally, but we may assume we know the mass of all nuclei involved.

    The question is then what is the threshold energy for the photon for this reaction to occur, assuming that the Q value is negative and known, and that the parent nuclei starts at rest?

    2. Relevant equations

    Conservation of momentum and energy (we assume non-relativistic at least for now)

    3. The attempt at a solution

    So I know that essentially I want to conserve both energy and momentum to work out the kinetic energy of both of the daughter nuclei. This result - the Q value would then be the required photon threshold energy. The problem arises in that I can't find solutions for the daughter kinetic energies in terms of the photon energy without introducing daughter nuclei velocities to my equations, essentially providing more unknown variables.

    A few hints would be greatly appreciated.

  2. jcsd
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