New gammametric systems for nondestructive testing

Gammametric testing in connection with modern computer technique results radiographic images of quality class I. The gammametric method is a well known technique in nondestructive testing. A narrowly defined X-ray or a gamma ray beam traverses a workpiece and is recorded by a gamma radiation detector. As the radiation is attenuated in the specimen, changes of its intensity may indicate discontinuities in the material such as flaws, inclusions or cracks. This commonly used method suffers from the disadvantage that no two-dimensional image is obtained as in radiography or radioscopy, but always a transmission curve of a linear section of the workpiece, yielding a quite difficult interpretation of the measurements. For this reason the gammametric method has been restricted to some special application, such as the inspection of very thick walls or for performing very accurate measurements