Thread: Pair production
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Apr29-09, 06:32 PM
Sci Advisor
P: 6,104
Quote Quote by malawi_glenn View Post
it can become when its energy is above twice the particle mass.

e.g. pair production of electron + positron is possible when the photon has energy above 2*m_e = 1022keV
Your description is somewhat incomplete. In order for pair production to take place the photon has to interact with a nucleus so that momentum conservation will hold. Alternatively if two photons collide (such as just after the big bang) pair production will also be possible.