Module 1: Radiological Fundamentals
2) It is a highly charged particle (charge of plus two) that is
emitted from the nucleus of an atom.
EO6 Identify the four basic
types of ionizing radiation
and the following for each:
a. Physical characteristics
d. Biological hazards
3) The positive charge causes the alpha particle (+) to strip
electrons (-) from nearby atoms as it passes through the
material, thus ionizing these atoms.
1) The alpha particle deposits a large amount of energy in a short
distance of travel.
2) This large energy deposit limits the penetrating ability of the
alpha particle to a very short distance.
3) Range in air is about 1-2 inches.
Most alpha particles are stopped by a few centimeters of air, a sheet
of paper, or the dead layer (outer layer) of skin.
1) Alpha particles are not considered an external radiation hazard.
This is because they are easily stopped by the dead layer of
2) Internally, the source of the alpha radiation is in close contact
with body tissue and can deposit large amounts of energy in a
small volume of living body tissue.
(Insert facility-specific information.)