 What
is Radiation?
Types
of Radiation
Ionizing/Non-ionizing
Radioactive
Decay
Fission
or Nuclear Fission
All material is composed of atoms. Atoms are
made up of various parts -- the nucleus that contains minute
particles called protons and neutrons and an outer shell made up
of other particles called electrons. The nucleus carries a
positive electrical charge, the electrons a negative electrical
charge. As electrons are bound to the nucleus of the atom, so
are the particles within the nucleus. These forces within the
nucleus work toward a strongly stable balance. The process by
which the nuclei of atoms work toward becoming stable is to get
rid of excess energy. Unstable nuclei may emit a quantity of
energy, or they may emit a particle. This emitted atomic energy
or particle is what we call radiation.
Types of
Radiation
There are two basic kinds of radiation: One
kind of radiation is tiny fast-moving particles that have both
energy and mass (weight) known as particle radiation. The other
kind of radiation is pure energy with no weight. This kind of
radiation is like vibrating or pulsating waves of electrical and
magnetic energy. The radiation waves are called electromagnetic
waves or electromagnetic radiation.
Ionizing/Non-Ionizing
Ionization is the process of removing
electrons from atoms, leaving two electrically charged particles
(ions) behind. Some forms of radiation like visible light,
microwaves, or radio waves do not have sufficient energy to
remove electrons from atoms and, hence, are called non-ionizing
radiation. The negatively charged electrons and positively
charged nuclei may cause changes in living tissue.
Radioactive Decay
Large unstable atoms can become more stable by
emitting radiation. This process is called radioactive decay.
This radiation can be emitted in the form of a positively
charged alpha particle, a negatively charged beta particle, or
gamma rays.
Fission
or Nuclear Fission
Some elements can split as a result of
absorbing an additional neutron. This is called fission or
nuclear fission. Such isotopes are called fissile isotopes. One
particular fissile isotope is uranium-235. This is the isotope
used in commercial nuclear reactors. When a nucleus fissions,
three important events occur that result in the release of
energy. These events are release of radiation, release of
neutrons (usually two or three), and formation of two new nuclei
(fission products).
Source: U.S. Nuclear Regulatory
Commission
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