Introduction to Nuclear
Radiation¾ Definitions
and
Terminology Handout
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Radioactivity- the emission of energy in the form of particles or
electromagnetic waves as a by-product of a nuclear reaction (i.e. nuclear
fission or fusion) or by spontaneous radioactive decay.
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Radiation- energy given off when certain substances undergo either
radioactive decay or some other nuclear reaction.
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Radioactive Decay- the spontaneous breakdown of an unstable atomic
nucleus.
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Nuclear Reaction Equations- utilize atomic symbols to describe a
nuclear process.
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Similar to chemical reaction equations
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Conserve charge and number of nucleons
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Example:
5. Nuclear Fission- splitting of an atomic
nucleus into two smaller nuclei of approx. equal mass, during which energy
is released.
6. Nuclear Fusion- joining of two atomic
nuclei of smaller masses to form a single nucleus of larger mass.
7. Types of Radiation:
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Gamma (g )- electromagnetic waves of
very short wavelength, high energy, and high penetrating ability¾
several cm. of lead to stop them.
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Alpha (a ) - charged particle consisting
of 2 protons and 2 neutrons; large relative size and charge give alpha
a low penetrating ability¾ skin, paper
or cloth can stop them. Very damaging to live human tissue inside the human
body.
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Beta (b ) - fast moving electrons or
positrons; small size and charge combine to give beta a penetrating ability
greater than alpha but less than gamma¾
a few mm. of aluminum can stop them.
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Neutron (n) - fast moving neutrons; penetrating ability and damaging
effects depend upon the neutron's energy.
8. Types of Radioactive Decay:
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Gamma - radioactive decay in which a gamma ray is given off.
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Alpha - radioactive decay in which an alpha particle is given off.
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Beta - radioactive decay in which a beta particle is given off.
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Two types: Beta minus decay and beta plus decay.
Beta Minus Decay
Beta Plus Decay
Go Back to Radioactivity Home Page
Copyright 1999, Thomas McNulty
Last updated 9 August 1999