1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Energy of a gamma particle

  1. Apr 27, 2015 #1
    1. The problem statement, all variables and given/known data

    Fluorine-18 is an isotope of fluorine often used in positron emission tomography, as it undergoes beta negative decay.
    1. a) Determine the decay equation for fluorine-18.

    2. b) If the positron emitted collides with an electron, it annihilates the electron and emits 2 gamma particles in the opposite direction. Determine the energy that one gamma particle has as a result of this collision. m(electron/positron) = 0.000549 u
    2. Relevant equations

    3. The attempt at a solution

    1) 189F---->188O+e-1

    2) Im not too sure about this one. Im assuming it has something to do with e=mc^2 but I'm not sure how to approach it
  2. jcsd
  3. Apr 27, 2015 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    There's a couple of inconsistencies in the stated problem and your solution:

    1) If fluorine-18 is used in PET, shouldn't it give off beta+ particles (positrons) instead of beta- particles (electrons)?

    2) This is not how a beta decay reaction works:

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Discussions: Energy of a gamma particle