惯性约束聚变靶丸高精度X射线数字成像

为了实现惯性约束聚变(ICF)靶丸几何尺寸的高精度、高效率检测,开展了靶丸X射线数字化成像系统的设计与研制。首先,分析了X射线直接投影成像和X射线透镜耦合显微成像的适用范围,根据ICF靶丸尺寸小、吸收衬度弱的特点,确定了基于X射线透镜耦合显微成像的技术路线。然后,分析了影响系统成像分辨率、图像衬度和测量效率的关键因素,确定了低几何放大成像,低电压、小焦点、高功率X射线源及高分辨CCD探测的总体技术方案,该方案能够有效抑制相衬效应和半影误差,解决了现有X射线数字成像设备测量靶丸时边缘扩展严重、尺寸测量误差大的问题。最后,对系统的性能进行了分析测试,实验结果表明,系统成像衬度良好,成像效率较高,分辨率优于0.5μm。靶丸几何尺寸的测量不确定度可达0.9μm(k=2),满足ICF靶丸几何尺寸高精度、高效率的检测需求。

High precision X-ray digital imaging of inertial confinement fusion capsules

To realize high-precision and high-efficiency measurements of the geometric dimensions of inertial confinement fusion(ICF)capsules,an X-ray digital imaging system applied to characterize the geometric dimensions of capsules was designed and developed.First,the X-ray direct-projection imaging and X-ray lens coupled microimaging were theoretically analyzed and a technical approach based on X-ray lens coupled microimaging was chosen due to its small size and the weak-absorption contrast of ICF capsules.Then,the key factors affecting the imaging resolution,image contrast,and measurement efficiency of the system were analyzed.A technical scheme of low geometric magnification imaging,a low voltage X-ray source,a small focus,and high power and high-resolution charge-coupled device(CCD)detection was determined.Utilizing this scheme,the phase-contrast effect and penumbra error can be suppressed effectively and the problems of serious edge expansion and large measurement error,which exist in X-ray digital imaging equipment used to measure the capsules,can be solved.Finally,the system performances were tested and the experimental results illustrate that the system has an excellent imaging contrast,high efficiency,and high resolution better than 0.5μm.The measurement uncertainty of the geometric dimensions of ICF capsules is approximately 0.9μm(k=2),meeting the high-precision and high-efficiency measurement needs of ICF capsules.