The Application On ICF Multi-shell Capsule Diagnose Using Phase Contrast Imaging

During the research on inertial confinement fusion (ICF) and high energy density physics (HEDP) are developing,there is crying for a diagnostic technique aim at low Z materials. Because of the weak absorption or no absorption of the low Z materials, the traditional X-ray imaging method based on absorption have very low contrast. A novel imaging technique, X-ray phase contrast imaging based on phase shift from a completely different way to solve the low Z materials imaging problem.In this thesis, the main purpose is to diagnose the multi-layer capsule shell used in-line phase contrast imaging. Our work respectively unfolds in synchrotron radiation facility, micro-focus X-ray source, SG-II laser facility. The results show that phase contrast imaging is a new way for the precise diagnose on ICF and HEDP research, it is worth further study.The main contents of this paper as follows:1. Review and sort out the development of phase contrast imaging. Introduce the theory,the most widely used in-line phase contrast imaging method. Respectively, the theory are transport of intensity equation(TIE)theory,contrast transfer function(CTF)theroy,general theoretical formalism (GTF) theory. And we propose an approach to obtain the optimum contrast and spatial resolution in phase contrast imaging.2. The simulation work is proposed for the current design of multi-layer shell capsule. It's based on CTF theory and under the refraction of geometrical optics. The results showed that phase contrast imaging can distinguish the hydrocarbon (CH) and polystyrene (PS) and absorption imaging is difficult to distinguish them.3. The research on multi-layer shell capsule using phase contrast imaging carried out with parallel light source and spherical light source. The experiment develop on Beijing Synchrotron Radiation Facility(BSRF) 4W1A beam line,Tongji University boer laboratory micro-focus X-ray source and BSRF micro-CT machine. Large number of experimental results obtained the best spatial resolution access to 2um, contrast 12%. Phase contrast imaging compared with absorption imaging has obvious advantages. the work has filled the domestic gap in this field4. The black-white fringe in phase contrast imaging has been found, named it phase contrast halo zone and dark zone. Define the width of halo zone and dark zone as an important part of image quality.5. The research on pinhole-aperture point-projection backlit imaging carried out in SG-II laser facility. Through the protection of ablation debris, through the research on ablation plasma effect, through the improved signal to noise ratio and so on. The imaging system spatial resolution can be achieved 7 um.6. The research on phase contrast imaging carried out with Laser-driven backlit X-ray source on SG-II laser facility. The spatial resolution achieved 7um, contrast 16.7%.In particular, obtained a preliminary dynamic multi-layer shell capsule imaging. The work is world's first using phase contrast imaging in high energy density physics (HEDP) environment.