The positron is the antiparticle of the electron. The positron has the same mass as an electron, an electric charge of +1, and a spin of 1/2. When a low-energy positron collides with a low-energy electron, there is mutual annihilation, which results in the production of two gamma ray photons. Positrons can be generated by positron emission radioactive decay, or by pair production from a sufficiently energetic photon. The positrón was discovered by Carl David Anderson in 1932 when he studied the cosmic ray.