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|  Radiological Assessor Training
DOE-HDBK-1141-2001
Instructor's Guide
D. Common uses and hazards
Obj. 3
Identify the most common use of x-rays.
X-ray machines are most commonly used for
The energy of the x-rays required will
radiography, or the examination or inspection of
depend on the density, thickness, and
the structure of materials by non-destructive
atomic number of the objects or structures
means.
to be imaged, or examined. Dense, thick,
high atomic number objects or structures
require more energetic x-rays.
X-ray machines used in medicine are fairly
standardized in appearance, and in the way they
Show OT 12.7.
are installed. That is not true of x-ray machines
used for industrial applications. X-ray machines
Obj. 4
may be fixed installations, mobile units, or
Identify the potential hazard associated
completely enclosed cabinet systems. The
with x-rays.
cabinet x-ray systems are commonly used for
security applications (e.g., baggage inspection
units).
The major hazard from x-ray machines is the
external dose hazard to machine operators and
other people in the vicinity. No one should ever
be exposed to the primary (or useful) beam.
Exposure to leakage radiation (from the housing)
and scatter radiation should be reduced by
appropriate controls.
Show OT 12.8.
IV. Analytical x-ray machines
A. Fluorescence analysis
Characteristic x-rays that result from ionization of
atoms can be used to identify atoms, since the
characteristic x-rays will have energies that are
unique to that element. This forms the basis for
x-ray fluorescence spectroscopy. A sample to
be analyzed is irradiated by a beam of high-
intensity x-rays. The x-rays ionize atoms in the
sample, which emit characteristic x-rays when
the electron shell vacancies created by
ionization are filled.
Module 12 7
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