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Positron Emission

  1. Apr 7, 2014 #1
    • Member advised to use the homework template for posts in the homework sections of PF.
    Hi, i have a question here, but i dont know how to write a lengthened answer on it. I just know what happens and thats about it.

    Questions: A positron can be produced by pair production or by positron emission from a proton rich nucleus.

    a) Describe the changes that take place in a proton rich nucleus when it emits a positron.

    A nucleus with too many Protons will be unstable, so some of the protons will turn into neutrons, and a positron will be emitted as a result I want to be able to write a more detailed answer, because say for example that was a 2 or 3 mark question in an exam paper, i dont think i will get the full marks.

    I also cannot think of a second point for this question:

    b) State two ways in which pair production of a positron and an electron differs from positron emission.

    -In pair production, an electron is produced along with a positron
    -(i cant think of a second way)

  2. jcsd
  3. Apr 7, 2014 #2


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    For (a), can you be more specific than "some"? Only one event will happen at a time. Is there more than one kind of event? Is anything else emitted? You could say something about elements.
    For (b), the elaboration of (a) may suggest some aspects. Also, for pair formation, is anything else required to be present for the event to occur?
  4. Sep 18, 2016 #3
    You were almost there.
    For anyone still wondering:
    (a) A nucleus with too many protons (proton-rich) will be unstable, so a proton will turn into a neutron and emit a positron as a result. This is called beta + decay (opposite of normal beta decay).

    (b) 1: Pair production: positron created by two photons colliding. Positron emission: positron created by beta + decay.
    2: Pair production: An electron is also created. Positron emission: no electron is created (no other products)
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