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X射线数字成像检测是工业无损检测的新技术。非胶片实时数字成像检测以其高效率、低成本 ,特别是数字图像的可交换性和存储方便等特点成为射线检测的发展趋势。通常使用的由射线像增强器、视频摄像机、图像采集卡和计算机组成的系统成像质量差且只能在低能X射线下使用 ,作者经过反复研究和实验 ,研制了基于单晶闪烁屏和科学级CCD相机的可用于高、低能X射线高分辨率、高对比灵敏度数字成像检测系统。介绍了整个检测系统的组成 ,设计了科学级制冷CCD相机、预处理电路、A/D转换电路、微机EPP方式快速数据采集电路和软件等。给出了某铝铸件 (厚 1 5 0mm)在加速器高能X射线下的成像结果。实验证明该系统比普通像增强器和视频相机组成的系统具有适应射线能量范围宽和成像质量好的优点 (成像时间长一些 )。系统的空间分辨率大于 3lp/mm ,检测物体 5 0mm(等效钢厚 )以上时 ,对比度灵敏度小于 1 %。
X-ray digital imaging detection is a new technology for industrial NDT. Non-film real-time digital imaging detection with its high efficiency, low cost, especially the interchangeability of digital images and storage convenience has become the trend of ray detection. The commonly used imaging system consisting of a ray image intensifier, a video camera, an image acquisition card and a computer has poor imaging quality and can only be used under low-energy X-rays. After repeated research and experiments, the author developed a single-crystal scintillation screen and a scientific-grade CCD camera can be used for high and low energy X-ray high-resolution, high contrast sensitivity digital imaging detection system. The composition of the whole detection system is introduced. The design of a scientific grade refrigeration CCD camera, preprocessing circuit, A / D conversion circuit, PC EPP fast data acquisition circuit and software are introduced. The imaging results of an aluminum casting (thickness 150 mm) under high energy X-ray accelerator are given. Experiments show that the system has the advantages of wide energy range and good imaging quality (imaging time is longer) than ordinary image intensifier and video camera system. The spatial resolution of the system is greater than 3lp / mm and the contrast sensitivity is less than 1% for objects above 50mm (equivalent steel thickness).