Study On Key Technology Of X-ray Imaging For Plasmas Based On Spherically Bent Crystal

It can be produced the inexhaustible and clean energy by Inertial confinementfusion (ICF), whose physical phenomena are similar to hydrogen bomb implosion andastrophysics. The research on ICF is important significance for our country energysustainable development, the defense security and astrophysics research.In the field of inertial confinement fusion, Physics experiments and Plasmasdiagnostics are very important research section. Since a large number of problems exit(i.e., the theoretical analysis and numberical simulation, technology of the targetfabrication and limited output power of the high power laser devices), the developmentof ICF diagnostic technology has more important scientific and outstanding practicalsignificance. It can be obtained X-ray spectral information of high-temperature plasmaand monochrome X-ray spatial information of ICF target implosion by the X-rayimaging system based on spherically bent crystal. These informations can reveal theplasma characteristics and behavior of ICF target, understand the energy absorptionmechanism of laser beam and provide the theory basis for the optimum coupling designof the drive and target. It can be used to evaluate the driven symmetry and uniformity oflaser radiation, analyse the promote layer motor process of target implosion andestablish the theoretical model of ICF radiation driven. The research of X-ray imagingsystem with spherically bent crystal is supported by the National Natural ScienceFoundation of China-NSAF (No:10976033). In the work, We researched the imagingtheory of spheically bent crystal; the imging system based on spheically bent crystalwas build up; the X-ray spectral imaging and monochrome X-ray backlight imagingexperiments were carried out. The main research content include:1) Using the X-ray Bragg diffraction theory and the Rowland circle property, thetheory of Johann spectrometer is analysed; Based on the theory of Johann spectrometer,the theory of the imaging based on spherically bent crystal is further studied. The X-raybacklight imaging theory and property of spherically bent crystal with the Bragg angleat normal incidence and far away normal incidence are analyzed. Using the diffractiontheory of crystal and the Bragg angle deviation, the relation of imaging systemparameters and the reflected energy of spherically bent crystal for the source on theRowland circle and the source positon not on Rowland circle are analyzed. Theseper-working establish the theoretical foundation for the investigation of spherically bent crytal system.2) When the X-ray arrives at the crystal surface, if the X-ray fulfill the Braggdiffraction and the Bragg angle inside the Darwin width, the crystal is considered as a“mirror-like”system, which means that the each ray is reflected at the crystal surfacefollowing the laws of specular reflection. Based on the imaging approximate, theimaging simulation platform for spherically bent crystal is established using the raytracing software SHADOW. The imaging simulation of the X-ray backlight imagingsystem based on spherically bent crystal with the Bragg angle far away normalincidence is studied with the imaging simulation platform to verify the imaging systemimaging. In addition, using the imaging simulation platform, the relationships betweensystem parameters and imaging performance are studied. These simulation worksprovide the theory and reference for the actual application of the X-ray system based onspherically bent crystal.3) The X-ray imaging system based on spherically bent crystal is developed,according to the imaging property of spherically bent crystal and experimental condition.The performances of imaging system key components are analyzed. Using the X-rayattenuation theory, the transmissivity of the filter is studied and the transmissivity of Al,Be and Ti filter are compared. According to the alignment of the crystal imaging systemand the effective detection area of different detectors, two practical alignmenttechnologies are proposed.4) The spectral imaging experiment is performed with the X-ray imaging systembased on spherically bent crystal to obtain the spectral resolution. The X-ray spectralimaging test experiment is carried out with spherically bent Quartz crystal. The resultindicates that the spectral resolution of the imaging system is1027; the imaging systemmeets the demand of spectrum diagnosis. The X-ray spectral imaging experiment ofhigh-temperature plasma is carried out on “yang” accelerator with spherically bentQuartz crystal. The diagnostic result shows that the spectral resolution of the imagingsystem is1092, which is consistent with the spectral resolution theoretical model.5) The monochrome X-ray backlight imaging experiment is carried out based onspherically bent crystal. In the X-ray backlight imaging test experiments, the imagingsystems with Quartz and Mica crystal are capable of the two-dimensional, spatially-resolved, monochromatic backlight mesh imaging. The experimental results show thatthe imaging systems provide83μm and86μm spatial resolutions respectively, whichare adequate for monochromatic X-ray backlighting imaging diagnosis. The X-ray backlight imaging experiments of high-temperature plasma using the imaging systemswith spherically bent Quartz crystal for the first time are performed on the SG-IIIprototype facility and on the “Yang” accelerator at the Chinese Academy of EngineeringPhysics. The diagnostic results demonstrate that the spatial resolution of the imagingsystem on “Yang” accelerator is75μm and on the SG-III prototype facility is5μm.