 |
|||
|
|
|||
|
|
|||
| ||||||||||
|
|  Radiological Assessor Training
DOE-HDBK-1141-2001
Student's Guide
For some operations, the size of the useful
beam must be adjusted by the operator. An
adjustable collimator is essentially a set of
movable lead sheets. Two sheets restrict the
width of the beam, and two sheets restrict the
length of the beam. The operator can then
adjust the size of the beam to any desired
combination of length and width.
Often, the lowest energy x-rays are not desired
in the beam. The low energy x-rays can be
filtered out by placing absorbing material (called
filters) in the path of the beam. Aluminum or
copper is commonly used, depending on the
energy of the machine. The addition of filters
increases the average energy of the beam, since
the lower energy x-rays are removed from the
beam when they are absorbed by the filters.
D. Common uses and hazards
X-ray machines are most commonly used for
radiography, or the examination or inspection of
the structure of materials by non-destructive
means.
X-ray machines used in medicine are fairly
standardized in appearance, and in the way they
are installed. That is not true of x-ray machines
used for industrial applications. X-ray machines
may be fixed installations, mobile units, or
completely enclosed cabinet systems. The
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.
Module 12 - 4
|
|
Privacy Statement - Press Release - Copyright Information. - Contact Us |
Click
here for thousands of PDF manuals