137 Cs - test source . The radioactive material is located in the two shiny metallic bodies, each of which represents the enclosed radiator. The yellow covers are transport containers made of lead.
Partial section of a capsule typically used in radiation therapy: A. Radiation protection container according to international standards (mostly lead) B. Bracket C. Radiation source consisting of D. a welded steel container E. Steel lid F. and an inner shield, mostly made of a uranium or tungsten alloy, which surrounds the G. cylinder with radioactive material, often cobalt-60. The diameter of the inner cylinder is 30 mm.
An enclosed radioactive substance , also an enclosed emitter , is defined under nuclear law as a radioactive substance that is encased or embedded in such a way that the escape of radioactive substance is prevented with certainty in the event of normal operational stress. The object in which the material is encased or in which it is embedded must measure at least 2 mm in one dimension so that it is difficult to incorporate the object.
Sealed radioactive substances are to be differentiated from open radioactive substances , which are defined as all radioactive substances that are not enclosed.