Alpha particle Ð Is a
positively charged atom that is released in the disintegration of radioactive
elements and that consists of two protons and two neutrons
Background Radiation Ð The
nuclear radiation that arises naturally from cosmic rays and from radioactive
isotopes in the soil and air.
Beta particle Ð A charged
electron emitted during certain types of radioactive decay, such as beta decay.
Critical Mass Ð The minimum
mass of a fissionable isotope that provides the number of neutrons needed to
sustain a chain reaction.
Fission Ð The process by
which a nucleus splits into two or more fragments and releases neutrons and
energy.
Fusion Ð The process in which
light nuclei combine at extremely high temperatures. Forming heavier nuclei and
releasing energy
Gamma Ray Ð the high-energy
photon emitted by a nucleus during fission and radioactive decay
Hal-life the time required
for half of a sample of a radioactive substance to disintegrate by radioactive
decay or by natural processes.
Nuclear Chain Reaction Ð A
continuous series of nuclear fission reactions.
Nuclear Radiation Ð The
particles that are released from the nucleus during radioactive decay.
Radioactivity Ð The process by which an unstable nucleus emits one or more particles or energy in the form of electromagnetic radiation
Radioactive tracer Ð A radioactive material that is added to a substance so that its distribution can be detected later.
Rem Ð The quantity of ionizing radiation that does as much damage to human tissue as I roentgen of high-voltage x rays does.