Background RadiationFilling all space, e.g. the radiation from the early, hot universe.
becquerelThe special name for the unit that expresses a measure of activity. One becquerel corresponds to one disintegration per second of any radionuclide.
beta particleA high-speed electron or positron, emitted in radioactive decay.
Beta particle (beta radiation, beta ray)An electron of either positive charge (ß+) or negative charge (ß-), which has been emitted by an atomic nucleus or neutron in the process of a…