The simultaneous formation of an electron and a positron as a result of the interaction of a photon of sufficient energy (> 1.02 MeV) with the field of a particle.
Source:
PAC, 1982, 54, 1533. 'Glossary of terms used in nuclear analytical chemistry (Provisional)' on page 1547 (https://doi.org/10.1351/pac198254081533)