反射式微焦点X射线管的整体研发

发布时间：2018-08-01 13:15

【摘要】：微焦点X射线管是一种焦斑尺寸在1~100微米的X光管。由于它具有高的空间分辨率,这种光管被广泛用于生物医学,生化动力学,工业无损检测,X射线显微镜以及微型CT等行业。本文围绕反射式X射线管的整体设计展开研究。X射线管阳极,主要包括靶材料、阳极体以及阳极与玻璃外壳的封接部分。本文选用TU1无氧铜作为阳极主体材料、纯钨作为靶材料,阳极与玻璃外壳的连接采用了4J29可伐合金作为过渡结构。设计了一种熔铸方法用于钨靶和铜体的连接成形,研究了可伐合金与K5钼族玻璃在匹配封接过程中封接时间、温度、气氛环境对封接质量的影响。最后提出了一些阳极散热方面的改进意见。X射线管阴极,包括电子发射结构、阴极罩以及阴极与玻璃外壳的连接部分。设计采用纯钨热发射阴极、阴极主体结构选用4J29可伐合金、各结构间采用点焊的连接方式。阴极与玻璃的连接设计了一种可伐柱的过渡结构,该结构可以良好的平衡阴极电位。在射线管的整体装配过程中,重点研究了电子发射系统的原理并通过模拟手段得出了一套针对确定尺寸X光管的对焦手段。电子发射系统是X射线管的关键部分,本文基于MATLAB平台分别使用蒙特卡洛法、有限差分法和龙格库塔法对电子发射系统的热发射、聚焦电场电位分布、电子束轨迹进行了模拟。以自行设计的光管作为模型,分析了模拟数据,得出理论最佳焦距为5.25毫米。最后对试做X光管进行了测试,包括给定输入条件下的反馈电流测试、疲劳测试、图像测试以及焦斑尺寸测试,得出了试做管的焦斑尺寸为长直径60μm、短直径30μm,优于国内同型号产品。分析了测试结果及结果中的不足,提出了一些改进方案。
[Abstract]:The microfocal X-ray tube is an X-ray tube with focal spot size of 1 渭 m. Because of its high spatial resolution, the light tube is widely used in biomedical, biochemical dynamics, industrial nondestructive testing, X-ray microscopy and micro CT. In this paper, the whole design of the reflective X-ray tube is studied. The anode of the X ray tube mainly includes the target material, the anode body and the sealing part between the anode and the glass shell. In this paper, TU1 oxygen-free copper is used as anode material, pure tungsten is used as target material, and 4J29 Kovar alloy is used as transition structure in connection between anode and glass shell. A fusion casting method was designed for the bonding forming of tungsten target and copper body. The effects of sealing time, temperature and atmosphere on sealing quality of Kovar alloy and K5 molybdenum glass during matching sealing process were studied. Finally, some improvements in anodic heat dissipation are proposed. The X ray tube cathode includes the electron emission structure, the cathode cover and the connection part between the cathode and the glass shell. The design adopts pure tungsten thermal emission cathode, the main structure of the cathode is 4J29 Kovar alloy, and each structure is connected by spot welding. A transition structure of thinning column is designed for the connection of cathode and glass. The structure can balance cathode potential well. In the whole assembly process of ray tube, the principle of electron emission system is studied emphatically and a set of focusing means for determining the size of X-ray tube is obtained by means of simulation. Electron emission system is a key part of X-ray tube. Monte Carlo method, finite difference method and Runge-Kutta method are used to simulate the thermal emission, focusing electric field potential distribution and electron beam trajectory of electron emission system based on MATLAB platform. Using the self-designed light tube as the model, the simulation data are analyzed and the theoretical optimum focal length of 5.25mm is obtained. Finally, the X-ray tube was tested, including feedback current test, fatigue test, image test and focal spot size test under given input conditions. The focal spot size of the tube is 60 渭 m in long diameter and 30 渭 m in short diameter, which is superior to the same product in China. The test results and the shortcomings of the results are analyzed, and some improvement schemes are put forward.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN14

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