Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How are positrons made?

  1. Mar 15, 2013 #1
    Hi awesome physicists!
    I'm interested in particles and particle accelerators. I've been wondering about how anti-matter is made. I've researched (using the infinite power of google) and have discovered that positrons (or anti-electrons) can be made by firing an electron at a heavy element, which, when the electron changes path and gives off high-energy photons which supposedly can spontaneously turn into a positron-electron pair. This sounds wierd to me as I don't understand this spontaneous change stage.
    What really goes on here?

    Thanks,
    Joe
     
  2. jcsd
  3. Mar 15, 2013 #2

    QuantumPion

    User Avatar
    Science Advisor
    Gold Member

    The phenomenon you are referring to is called pair production, where by a photon of energy greater than two times the rest mass of an electron, when interacting with a nucleus, can turn into an electron and positron pair.
     
  4. Mar 16, 2013 #3
    Thanks. And with regard to the experiment I referred to earlier (when electrons are fired at a heavy element etc), if a cold cathode was used to fire the electrons, would the experiment be successful in the sense that an electron-positron pair would be created? And if so, would the amount of gamma radiation produced be harmful if a human was standing next to it as it happened?
     
  5. Mar 21, 2013 #4

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    If you accelerate the electrons sufficiently, sure.
    That just depends on the intensity.
     
  6. Mar 21, 2013 #5
    Can I make a silly post and say

    Sorry, I'll just shut up
     
  7. Mar 25, 2013 #6
    Cool. Could anyone tell me how many electrons produce how many antiparticle pairs (theoretically)?
     
  8. Mar 25, 2013 #7

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    That really depends on the energy. High-energetic electrons in matter can produce many (10, 100, 1000, ... just depends on the energy) electron/positron pairs in their showers.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: How are positrons made?
  1. How is antimatter made (Replies: 9)

  2. Manufacture of positrons (Replies: 21)

Loading...