The variation of multi-layer shell capsule in implosion process is the most important part of inertial confinement fusion.Phase contrast imaging which relies on gradients of the refractive index and wave interference is proposed to characterize the typical implosion capsule.The experiments are performed on the ShenguangⅡlaser facility.The point-like X-ray source at 4.75 keV can be efficiently produced from laser interactions with Ti target and observed by pinhole-point backlight technique.The phase contrast images obtained with point-like X-ray source provide complementary information about the multi-layer shell capsule,and the spatial resolution is better than 10μm.The X-ray phase contrast imaging shows more detailed features than absorb imaging,and good agreement with one-dimensional numerical simulations.%内爆压缩过程中多层球壳靶丸变化规律的研究是惯性约束聚变的核心内容.利用相衬成像技术可以提高低Z材料分界面成像衬度的特点在神光Ⅱ大型激光装置上开展了相关研究.实验通过激光打Ti靶和针孔点背光的方式产生4.75 keV的X射线微点源,针对内爆压缩过程中的靶丸样品投影成像获得了清晰的多层球壳靶丸图像,空间分辨率优于10μm.同时利用一维流体力学数值模拟程序分析了球壳运动的过程,实验结果与数值模拟结果符合较好.表明了X射线相衬成像技术在高能量密度物理环境下仍然能够提高低Z材料分界面的衬度,获得高质量的物理图像,能够广泛应用于可控聚变能源、天体物理等前沿科学领域.
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