Multi-Energy Radioscopy - An X-Ray Technique for Materials Characterization
Multi-energy radioscopy with normalization to a reference material is basically an easy-to-realize method with no special requirements to the equipment. Investigations as described above can be done with any radioscopic system. It is possible to identify a material by the comparison of two radioscopic images obtained at different accelerating voltages. In order to evaluate composite materials and to characterize material layers which are covered by a surrounding medium three irradiation energies are necessary. Therefore, the images obtained at three accelerating voltages should be imaged as color radioscopic images and evaluated by means of color image processing. Experiments and simulation calculations showed that this technique also allows the identification of materials in layered systems. An important result of simulation calculations is the fact that in many cases signal noise and digitalization errors are critical due to the little differendes in the gray-scali valued of two norm alized images. Therefore, low-noise images, i.e. the application of high integration times and an improved gray-scale value resolution (12-16 bit), are necessary. The practical advantage of this technique is the testing of components which can't be accessed wiht conventional analytical methods. This is especially a problem for the characterization of inner layers in layered structures. Multi-Energy Radioscopy can alos be applied to composite materials.