Pair Production
Electromagnetic radiation interacts with matter in different ways. One way is Pair Production where a photon creates 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.
Can a \(2 \; [\text{MeV}]\) photon create an electron-positron pair?
The incident photon energy must be larger than the total rest mass energy:
\(E_{min} = 2m_e = 2\cdot0.511\)
\(E_{min} = 1.022 \; [\text{MeV}]\)
Therefore, we can determine the photon has sufficient energy to create an electron-positron pair.
Calculate the kinectic energy of the electron-positron pair made from a \(2 \; [\text{MeV}]\) photon.
The kinectic energy of the electron-positron pair can be determined as such:
\(KE = E - 2m_e\)
\(KE = 2 - 2\cdot0.511\)
\(KE = 978 \; [\text{keV}]\)
Therefore, we can determine the kinetic energy of the electron-positron pair is \(\boldsymbol{978 \; [\textbf{keV}]}\).