Atom
which decays radioactively. In the context of non-destructive testing,
this is understood to mean preparations for radiographic examination,
usually radiography. Th type and therefore the energy level (gamma
radiation) is chosen depending on the case (material and workpiece
thickness). The most important radionuclides in the non-destructive
testing of components are cobald60, iridium192 and selenium75.
Furthermore,
the size and activity determine the exposure time which should be
chosen in a recording situation. The activity of the radionuclide, i.e.
the radioactive decay per unit of time, decreases as time passes
(half-life period). These are different depending on the type (cobalt60
5.3 years, iridium192 74 days).
The
radioactive substances are welded in capsules which are stored shielded
in appropriate transportation containers or devices for working with
isotopes.