Abstract
The radioactive source ytterbium-169 emits a 52-kev characteristic x-ray and various gamma rays with energies from 65 kev to 310 kev. Ytterbium sources in small exposure units weighing about 20 pounds are useful for radiography of castings, weldments, assemblies, and other forms of various materials, such as aluminum, magnesium, iron, plastics, and wood. Radiography with Yb169 produces no hazard from electrical shock or explosion. Radiation scattered from air, the object, and surrounding materials is less with Yb169 than with conventional x-ray sources, Ir192, or Co60. Therefore, portable radiographic applications can be made with less difficulty in protection of personnel.