Exploring the Creation of Positrons for Aspiring Physicists"

[tinypositrons]

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 weird to me as I don't understand this spontaneous change stage.
What really goes on here?

Thanks,
Joe

 

[QuantumPion]

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.

 

[tinypositrons]

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?

 

[mfb]

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?

If you accelerate the electrons sufficiently, sure.

And if so, would the amount of gamma radiation produced be harmful if a human was standing next to it as it happened?

That just depends on the intensity.

 

[Kevin2341]

Can I make a silly post and say

When a mommy electron and a daddy photon get really excited...

Sorry, I'll just shut up

 

[kaseron]

Cool. Could anyone tell me how many electrons produce how many antiparticle pairs (theoretically)?

 

[mfb]

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.