What are radioactive sources?
Radioactive sources are used throughout the world for a wide variety of peaceful and productive purposes in industry, medicine, research and education, and in military applications. These sources utilize radioactive materials that are firmly contained or bound within a suitable capsule or housing; although some sources involve radioactive materials in an unsealed form. Until the 1950s, only radionuclides of natural origin, particularly radium-226, were generally available for sources. Since then, radionuclides produced artificially in nuclear facilities and accelerators have become widely available, including cobalt-60, strontium-90, caesium-137 and iridium-192. Radioactive sources vary widely in physical size and properties, the amount of radiation they emit, and type of encasing. Some are portable instruments, such as gauges for taking measurements, while others are fixed pieces of equipment, such as a radiotherapy machine for cancer treatment. The IAEA has categorized radioactive so
