Research on Improvement of Receiving-Detecting Circuit for Digital Radiographic Systems with Advanced Spatial Resolution

Abstract

Radiographic inspection is among the most reliable methods for inspection of pipelines and metals. The worldwide trend of transition from film radiography to digital radiography requires developmentof advanceddigital radiography systems (DRS). The main task in developmentof DRS is the improvement of spatial resolution (SR). The pixel size of the X-ray film is several microns while solid-state detector pixels have dimensions of several hundred to several thousand microns. For the most common detectors of “scintillator-photodiode” (S-PD) type, it is impossible in principle to obtain the film pixel sizes. However, the detecting ability for substances that differ by their density and atomic number achieved using “scintillator-photodiode” detectors is by several orders higher. Using the known method of digital radiography with a standard experiment scheme, but with dual-energy detector arrays, this study aimed at showing that it could be possible to substantially increase the accuracy of separation of substances in the inspected object by their atomic number.The sensitivity of the method was increased by using a multi-energy approach and detectors that have substantially different sensitivity in the low- and high-energy range of the X-ray emitter spectrum. Using the developed instruments and software, dual energy CT and 3D imaging of different objects such as welding, fragment of bone and tissue, and bags containing potentially hazardous items can be performed.