In: Physics
(2) Explain the concept of pair production and pair annihilation
PAIR PRODUCTION
Conversion of a photon into an electron-positron pair on its interaction with the strong electric field surrounding a nucleus is called pair production. Pair production refers specifically to a photon creating an electron–positron pair near a nucleus.For pair production to occur, the incoming energy of the interaction must be above a threshold of at least the total rest mass energy of the two particles, and energy and momentum should also be conserved in that situation.
PAIR ANNIHILATION
The converse of pair production in which an electron and positron
combine to produce two photons is known as annihilation of
matter. In the pair annihilation, the
electron and positron in the stationary state combine with each
other and annihilate. For the momentum conservation, the
most frequent process in pair annihilation is making two photons
that have exactly opposite direction and the same amount of
momentum.