Abstract: A radioactive source holder for use in radiation absorption gauging is disclosed. The radiation source holder includes a housing body having a cavity therein through a first surface for receiving a plurality of radioactive sources. The radioactive sources are permanently retained in the housing by epoxy or tape. A shipping container for the radioactive source holders is also provided. The shipping container includes first and second cylindrical members formed from lead which are disposed adjacent to the first surface of the housing body and a second opposite surface. The container bodies are attached to the housing body by a retainer such as bolts. Further, a radioactive source assembly is disclosed which includes a plurality of radioactive source holders along with an end shield which are attached to a mounting plate which may be received on a mounting bracket associated with the radiation absorption gauging system.