三维非相干X射线编码全息成像技术研究

Among the challenges in inertial confinement fusion is diagnosing and understanding the conditions in the hohlraum. Therefore imaging with simultaneous high spatial, high temporal and multidimensional resolution is critical for the future. There have been many attempts to peer inside the hohlraum to see exactly what happens, which can only give two-dimensional imaging information. Theoretically, classical Fresnel zone plate encoded holography enables three dimensional imaging, but the associated problems of out-of-focus artifacts limited its application. In this project, we will study the zone plate coding imaging technology, fully understand the factors restricting its realization of accurate three-dimensional imaging, and study the technology of suppressing non-focus artifacts interference and improving the quality of reconstructed image. Based on binary Gabor band plate, we hope to propose a method that can realize the accurate reconstruction of three-dimensional objects without non-focusing artifacts by single-shot and single-angle coding imaging of the targets. That is the three-dimensional incoherent X-ray coded holographic imaging technology which is suitable for ICF hohlraum three-dimensional imaging. The technology would be demonstrated by theoretical simulation and demonstration experiments. This work would offer new potential opportunities for three dimensional x-ray imaging of hohlraum in inertial confinement fusion research.

在激光驱动惯性约束聚变实验研究中，对内爆过程中黑腔内等离子体膨胀区域和内爆靶丸区域的精密成像具有重要意义。目前通用的诊断设备都只能给出二维的成像信息，这限制了对靶丸内爆辐照均匀性和内爆对称性的更精密诊断。传统的Fresnel编码成像技术可实现三维成像，不过其重建图像会受到较强背景噪声和非聚焦赝像的影响，这限制了其应用。本项目将深入研究波带片编码成像技术，充分了解限制其实现精确三维成像的因素，研究抑制波带片编码成像非聚焦赝像干扰并提高重建图像质量的技术，并基于二值化Gabor波带片提出一种可通过对三维目标的单发次单角度的编码成像、使用特定的重建算法后可实现三维目标的精确重建（无非聚焦赝像和旁瓣干扰）的技术，即适用于ICF黑腔三维成像诊断应用的三维非相干X射线编码全息成像技术。并通过理论模拟和演示实验来验证这一技术。该技术可望用于黑腔内热等离子体区域的高分辨三维成像，促进对内爆过程的精密诊断。

在激光驱动惯性约束聚变实验研究中，对内爆过程中黑腔内等离子体膨胀区域和内爆靶丸区域的精密成像诊断具有重要意义。目前通用的诊断设备都只能给出二维的成像信息，这限制了对靶丸内爆辐照均匀性和内爆对称性的更精密诊断。传统的Fresnel编码成像技术可实现三维成像，不过其重建图像会受到较强背景噪声和非聚焦赝像的影响，这限制了其应用。本项目开展了三维非相干X射线编码全息成像技术理论研究，通过理论研究完善了三维非相干X射线编码全息成像的理论。建立了三维非相干X射线编码全息成像过程数值模拟程序，对三维非相干X射线编码全息成像技术进行了系统性的模拟研究，研究了各类因素对重建图像质量的影响，优化了图像重建算法。设计并制作了二值化Gabor波带片，搭建了应用于可见光波段的三维非相干编码全息成像技术验证平台，开展了原理验证实验，验证了三维非相干X射线编码全息成像技术的可行性。针对惯性约束聚变黑腔内硬X射线发光区域的三维精密成像诊断，设计了三维非相干X射线编码成像系统。本项目研究表明，三维非相干X射线编码全息成像技术在原理和技术上均是切实可行的，后续研究团队将继续推进本技术研究和工程化应用。