Positron

The positron is the antiparticle or the antimatter counterpart of the electron. The positron has an electric charge of +1, a spin of 1/2, and the same mass as an electron. When a positron annihilates with an electron, their mass is converted into energy in the form of two gamma ray photons.

A positron may be generated by positron emission radioactive decay, or the interaction of a photon with a charged particle (such as an atom's nucleus). This process is called pair production, as it generates one electron and one positron from the energy of the photon.