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Gamma Radiation

  1. Sep 2, 2012 #1
    Making it short : Do gamma rays ALWAYS accompany a nuclear reaction??

    I was thinking, since there are only three types of radioactive decay, alpha, beta and gamma. I don't quite understand how gamma radiation will always occur. Isn't it going to be just ONE of the three types?

    /Help :)
  2. jcsd
  3. Sep 2, 2012 #2


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    Staff: Mentor

    Gamma rays are (very) high energy electromagnetic radiation carrying away some of the energy produced by the decay. So just about any reaction can produce some amount of gamma radiation - all that's necessary is that the reaction release enough energy.

    If you want an analogy: You can burn many different fuels in many different chemical reactions and end up with many different combustion byproducts, but you'll likely always get some amount of heat as one of the outputs.
  4. Sep 2, 2012 #3
    So there aren't any reaction not accompanied by the release of gamma rays? I was having a hard understanding these concepts. Thanks for replying.

    EDIT: I'm asking since your word likely always was kind of vague. So, when are the times that gamma radiation will not occur?

    EDIT 2: I also saw it here: http://www.ndt-ed.org/EducationResources/CommunityCollege/Radiography/Physics/gamma.htm
    in the animation, it also says Gamma Decay / radiation ALMOST ALWAYS accompany alpha and beta decay. Same thing I'm not understanding: When does it not accompany nuclear decay processes?
    Last edited: Sep 2, 2012
  5. Sep 2, 2012 #4


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    An interesting question. I want to say that no, not all nuclear reactions cause gamma rays. For example, take Tritium, the unstable isotope of Hydrogen. It decays by beta decay and is used in products like gun sights to make them glow. I don't know for sure, but I would think that there would be little to no gamma radiation, otherwise it wouldn't be a safe product.

    There are more than three types of decay. See here: http://en.wikipedia.org/wiki/Decay_mode#Decay_modes_in_table_form
    Gamma radiation is defined as EM radiation emitted from the nucleus of an atom. An atom can easily decay and release more than one type of radiation. This can occur if the nucleus remains in an excited state after the decay, releasing a gamma ray photon when it makes the transition from the excited to the ground state.
  6. Sep 2, 2012 #5
    ^Thanks. Giving the Tritium example made me understand it better.. :)

    I also searched on the Tritium case and found out that after an electron is ejected, a small difference in energy with both sides of the equation (see website) exists. I can't really explain in that well but the website kinda does a great job explaining. Here's the quote I'm saying:

    As you said, the proton has slightly less mass than the neutron. The mass of the electron makes up for this somewhat, but if you do the math, you'll see that there's still some mass "missing" from the right side of the reaction. Energy takes up the slack: the electron comes out moving very fast, i.e., with lots of kinetic energy.

    In other reactions, the "leftover" energy sometimes manifests itself in different ways. For example, the nucleus that comes out is sometimes in an excited state--the remaining protons and neutrons have more energy than usual. The atom eventually gets rid of this extra energy by giving off a gamma ray.

    So, I kinda "get" where ALMOST ALWAYS came from. It's because the "excess" energy can be given to the ejecting particle, accelerating it, making the particle eject faster, OR the excess energy can be given off as a GAMMA RADIATION. So, there's really two possibilities, but GAMMA RADIATION happens more often.

    Thanks for the help! :)

    http://www.colorado.edu/physics/2000/isotopes/radioactive_decay.html [Broken]
    http://www.colorado.edu/physics/2000/isotopes/mass_conservation.html [Broken]
    Last edited by a moderator: May 6, 2017
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