快点火背光照相数值模拟

在激光惯性约束聚变实验研究中，诊断燃料层密度通常利用纳秒激光束辐照金属靶片产生特征X射线作为背光照明光源，对内爆球壳进行瞬态辐射照相，进而推断球壳内爆燃料层的密度。利用蒙特卡罗程序，对快点火X射线背光照相进行了研究，模拟了针孔成像中不同的针孔大小、障板厚度、背光能量对成像质量的影响，对于快点火实验中微米尺寸塑料小球，进行了诊断方案优化。模拟结果表明，综合考虑光通量及成像空间分辨，针孔半径为10 m时成像效果最佳；此时，采用2.7 keV的Mo背光源可以获得最佳的密度分辨。

Monte Carlo simulation on X-ray backlighting imaging in fast ignition research

In fast ignition researches, fuel density is usually diagnosed by X-ray backlighting imaging with an X-ray source produced by laser irradiating metal target. The simulation on the X-ray backlighting imaging has been performed using a Monte Carlo code(MCNPs). The influence on imaging quality induced by the radius and thickness of pinhole, and the energy of X-ray source were investigated. The simulation results show that, the combination of a pinhole with 10 μm radius and a X-ray source with 2.7 keV energy, corresponding to Ka line of Mo, is the optimum choice, when both the luminous flux and the spatial resolution of imaging are concerned.