Elektronpardannelsen

Elektronpardannelsen, also known as electron pair formation or electron pair creation, is a fundamental concept in quantum mechanics and atomic physics. It describes the process where an electron and its antiparticle, the positron, are spontaneously created from energy, typically in the form of a high-energy photon. This phenomenon is a direct consequence of Einstein's famous mass-energy equivalence principle, E=mc², which states that energy and mass are interchangeable.

For electron-positron pair creation to occur, the incoming photon must possess a minimum energy equivalent to the combined rest mass energy of an electron and a positron. This threshold energy is approximately 1.022 million electron volts (MeV). If the photon's energy exceeds this minimum, the excess energy is converted into the kinetic energy of the newly formed electron and positron.

This process typically happens when a high-energy photon interacts with the electromagnetic field of an atomic nucleus. The nucleus acts as a catalyst, absorbing some of the photon's momentum to conserve momentum in the interaction. Without the nucleus, the photon would not be able to create a pair because momentum would not be conserved. Electron-positron pair creation is a key process in high-energy astrophysics, playing a role in phenomena like gamma-ray bursts and the environment around black holes. It is also a measurable effect in particle physics experiments. The reverse process, where an electron and a positron annihilate each other to produce photons, is known as annihilation.