The Study Of The Portable High-resolution X-ray CCD Camera

X-ray imaging technology has the large potential applications and gets more and more attention from people, such as medical diagnosis, industrial non-destructive, safety inspection and so on. This paper mainly focused on designing a kind of X-ray Charge Coupled Device(CCD) camera with high resolution, low cost and low dose which is being suitable for some areas about dental diagnosis, printed circuit board inspection and other imaging detection of small parts.The main research content was that depending on the existing development situation of X-ray imaging devices, choosing high-resolution gadolinium oxysulfide(Gd2O2S) screen, first generation image intensifier, fiber optic taper and the CCD camera as the component. In the existing experimental conditions by using the method of optical fiber coupling, the image intensifier with X-ray Photosensitive screen and the CCD camera were coupled. Because of the low cost and high conversion efficiency, we used the Gd2O2 S as the conversion material and prepared the screen with thin coating layer thickness to meet the requirements of low dose X-ray irradiation and high resolution. In order to obtain high resolution at the cost of reducing the luminous brightness, in addition, the image intensifier can make up for the loss by enhancing optical image information. And the enhanced optical images were compliance with the CCD imaging conditions.This paper came up with a better coupling method that is attempting to make output screen of the image intensifier directly formed on a facet of the light cone, then coupled another facet of the light cone with CCD camera. This method not only can reduce costs but also improve the resolution of the system. Next, coupling the big end of fiber optic light cones with output end of image intensifier to simulate the above ideas, and then coupling the small end of fiber optic light cones with photo surface of CCD, finally the principle prototype was prepared and its resolution reached 13 LP/mm, realized the demand of high resolution.By adjusting the voltage and current of X-ray tube to control the X-ray luminous flux, the changes of image quality under different doses properly was analyzed. When taken the X-ray imaging testing, because of the difference of thickness and its internal material, radiation absorption coefficient of detected objects is also different. In order to obtain high contrast and clear image quality, selecting suitable X-ray dose is also one of the most important contents of this thesis.Using copper target X-ray tube as a source of radiation, for some real-time image information of imaging detection such as the fishbone of small yellow croaker, small leaves, chip card, row needle and row line, box-packed staple, the results clearly showed the veins of the leaves, the fishbone of small yellow croaker, and the architecture of chip card and so on which was satisfied the purpose of imaging detection. In addition, considering that this kind of X-ray CCD camera has certain quantum efficiency for deep ultraviolet(DUV), and using the DUV light-emitting diode(LED) light source for fingerprint detection, can observe the clear structure of the fingerprint.In a word, this method that directly coupling X-ray photosensitive screen with the input facet of first generation image intensifier, and then coupling the image intensifier with CCD by using the method of optical fiber coupling, realized the high resolution imaging under low dose. Ensuring the photosensitive screen is under the condition of high resolution, through image enhancement effect of the image intensifier, the contradiction between high resolution and quantum efficiency is overcame. This is a compromised technology for processing the image quality. In a certain extent, it provides a good direction for realizing the quantity production of products by using this technology.