CCD Based High Energy Large Field X-ray Digital Radiographic System

摘要

For high energy radiography and radioscopy of large objects, we usually use systems based on 2D scintillating screen and silicon intensified target (SIT) video camera. The SIT camera disadvantages and the imaging field size limitations (about 0.12 m~2) leads us to develop a new system based on a high sensitivity CCD camera optically coupled to a large field (about 0.5 m~2) Gd_2O_2S:Tb converter screen. In this communication, the design of the camera will be presented together with the constraints due to the large magnification factor required and to the sensitivity of the CCD camera to scattered radiation. The performance of the system will be illustrated on experimental results. This system has a field of view of 0.48 m~2 and a pixel pitch of 0.64 mm. The geometric resolution obtained at 8 MeV is close to 0.5 lp/mm and the sensitivity is close to 2% through 30 cm of concrete. The maximum speed of acquisition is 9 images/sec. Application of this high energy camera in the field of nuclear waste are presented.