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 Shenguang Ⅱ laser 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 10 μm. The X-ray phase contrast imaging shows more detailed features than absorb imaging, and good agreement with one-dimensional numerical simulations.

High flux, Multi-keV X-rays, can be efficiently produced from nano-second laser interaction with metal target. Multi-keV backlight X-ray source is very important in inertial confinement fusion and high-energy density physics research. The one-dimensional numerical simulation results propose a laser plasmas radiation model, and the model is compared well with Shenguang II experimental results. The pinhole-assisted point-projection (PAPP) backlight is improved by the model; the rear-on PAPP backlight for low-Z metal target and the side-on PAPP backlight for middle-Z metal target are developed. The experiment is performed on Shenguang II 9th laser facility. The static stream line obtained with novel PAPP backlight provides high-quality capsule image, and the spatial resolution is better than 10 μm. Results show that novel PAPP backlight has advantages of traditional PAPP in source brightness, spatial resolution and image contrast.

The plastic DD filled capsule implosion experiment is performed on Shenguang III prototype laser facility. One-dimensional hydrodynamic numerical simulations show that the implosion compression ratio can be controlled by changing the capsule ablator thickness. In experiments, two types of capsules are studied and most of important implosion parameters are collected, such as neutron yield, X-ray bang-time, trajectory, and shape of hot core. The comparison between post-simulations and experimental results is performed. In our experiments, the neutron yield is 6.8×107 and YOC1D reaches 34% for low compression ratio implosion; the neutron yield is 6.3×106 and YOC1D is only 2.3% for middle compression ratio implosion. Meantime, the shape of hot core obtains an extra higher Legendre partial (P2 is 18% and P4 is 5%). On another side, the trajectory and bang-time are compared with simulations well.

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Traditional implosion backlight imaging experiment has disadvantages of nonuniform X-ray source, low contrast ablator interface and high requirement for diagnostic device tuning precision. A novel design of multi-point X-ray source combined with phase contrast imaging developed and optimized based on experimental research performed on Shenguang-II facility is presented. The novel design can obtain high-quality experimental result with uniform X-ray source, clear interface between ablator and inner DD gas and large image view. At the same time, the new design using diagnostic silt instead of diagnostic hole improves tuning precision. The experimental result proposes that novel design of laser driven plasma point x-ray source combined with phase contrast imaging has advantage of area X-ray source combined with absorb imaging and can be widely used in inertial confinement fusion and high energy density physics.