What are radioactive sources examples?
In this article:
- Radioactive sources used in industrial radiography include both natural and artificial isotopes, selected for their radiation intensity, half-life, and suitability for imaging dense materials.
- Natural sources like radium and mesothorium emit very hard radiation, making them effective for inspecting thick objects, though they are costly and difficult to miniaturize.
- Artificial radioactive sources, such as cobalt-60 (Co-60), iridium-192 (Ir-192), and selenium-75 (Se-75), are produced in nuclear reactors and offer high purity and compact size for precise non-destructive testing (NDT).
- Source selection depends on factors like radiation wavelength, intensity, and specific activity, which influence image quality and safety in industrial applications.
- Modern NDT practices favor artificial isotopes due to their controllable properties, availability, and compatibility with portable radiographic equipment.
Natural radioactive sources:
The elements from this group which have been used for the purposes of industrial radiography are radium and mesothorium. These give a very hard radiation, making them particularly suitable for examining very thick objects. A disadvantage of natural sources, next to their high cost, which it is not possible to make them in dimensions small enough for good quality images and still give sufficient activity.
Artificial radioactive sources:
Artificial radioactive sources for NDT are obtained by irradiation in a nuclear reactor. Since 1947, it has been possible to produce radioactive isotopes this way in relatively large quantities and in a reasonably pure state and particularly of sufficiently high concentration; the latter being extremely important in NDT because the size of the source has to be as small as possible. Among the many factors deciding a source suitability for non-destructive testing are the wavelength and intensity of its radiation, its half-life and its specific radiation. In fact, only a few of the many artificial radio-isotopes available have been found to be suitable for industrial radiography.