ABSTRACT
T o fit the numerous applications for radiation processing in research, industry and other fields, irradiators conform to a variety of designs and
methods of operation. Because of the variety of designs, four general categories of irradiators have been established to facilitate preparation of standards [80-83]. Category I irradiators are self-contained, dry source storage irradiators. In this type of irradiator, the sealed source is completely contained in a dry container that is constructed of solid materials. The sealed sources are shielded at all times. Human access to the sealed source and the volume undergoing irradiation is not physically possible in its designed configuration. Category II irradiators are panoramic, dry source storage irradiators. In this type of irradiator, human access to the irradiation chamber is allowed whenever the shielded source, which is contained in a dry container that is constructed of solid materials, is not in use. The sealed source is fully shielded when not in use. The shielded source is exposed within the irradiation chamber that is rendered inaccessible during use by an entry control system. Category III irradiators are self-contained, wet source storage irradiators. In this type of irradiator, the sealed source is contained in astorage pool (usually water), and the source is shielded at all times. Human access to the scaled source and the volume undergoing irradiation is physically restricted. Category IV irradiators are panoramic, wet source storage irradiators. In this type of irradiator, human access to the irradiation chamber is allowed whenever the sealed source is fully shielded in the storage pool. The sealed source is exposed within the irradiation chamber that is maintained inaccessible during use by an entry control system.
