Krypton⁸⁵: A radioactive fission product. It has a ten year half-life and emits an electron of average energy 0.2 million volts and a 0.5 million volt gamma ray.
Leukemia: A usually fatal disease in which white blood cells are overproduced.
Local fallout: Radioactive fallout in the neighborhood of a nuclear explosion.
Megaton: The amount of energy released by a million tons of TNT.
Meson: A particle intermediate in weight between the electron and the proton. Actually, there are two kinds of mesons, called pi and mu. The pi meson weighs 276 times as much as the electron and is connected with the forces that hold the nucleus together. The mu meson weighs 212 times as much as the electron and contributes appreciably to the cosmic radiation.
Microsecond: One millionth of a second. It takes light 5 microseconds to go a mile.
Million volt particle: Short for million electron-volt particle.
Moderator: A material used in nuclear reactors to reduce the speed of neutrons.
Molecule: A combination of atoms held together chemically.
Mutation: A genetic change, which is transmitted to offspring and affects hereditary characteristics. Such changes in genes may be caused by radiation as well as chemical and thermal agents.