集束实验针孔成像与仿真分析北大核心CSCD

在激光装置实验中,通过小孔成像原理可获取黑腔靶中发射的X光图像的时间积分。提出一种3倍放大的新型成像设备用于集束实验,通过在与靶轴线夹角30°方向安装带多层镜选能的成像设备从而获取低能和高能段的X光时间积分图像,观察腔壁的再辐射现象。开展了用于集束实验针孔相机的研制工作,包括光路设计与结构设计,通过离线进行测试,在线实验进行打靶考核。进行成像光路仿真,模拟计算了两种镜子的选能效果,并通过光路仿真得到了多层镜、滤片和谱分布对成像结果的影响。采用FLASH对实验辐射场分布进行仿真,作为成像仿真的输入。最后,将此设备获取的成像结果与仿真计算得到的结果进行比较,实验结果与仿真结果基本一致,得到了X光信号强度的分布情况,获取了理想的实验数据,加深了对内部物理现象的理解。由此,建立了针孔成像的仿真能力,能够对成像结果进行预判,指导针孔相机的设计。

Simulation and analysis of pinhole imaging in first laser plasma interaction experiments

In the laser device experiment,the time integral of X ray image emitted from black cavity target can be obtained by the principle of keyhole imaging.A new imaging device with triple magnification is proposed for the first laser plasma interaction experiments,where X ray time integral images in the low and high energy segments are obtained by installing the imaging device with multi layer mirror at an angle of 30° to the target axis to observe the re radiation of the cavity wall.The development of a keyhole camera for the first laser plasma interaction experiments is carried out,including optical design and structural design.The system performance is tested off line and experimented online.The imaging optical path and the energy selection effect of two kinds of mirrors are simulated,and the effect of multi layer mirror,filter and spectrum distribution contribution on the imaging results is obtained through the simulation of the optical path simulation.FLASH is used to simulate the experimental radiation field distribution as an input to the imaging simulation.Finally,the imaging results obtained by the device are compared with the results obtained from the simulation calculations.The experimental results are basically consistent with the simulation results,obtaining the distribution of the X ray signal,the ideal experimental data,and deepening the understanding of the internal physical phenomena.Therefore,the simulation capability of pinhole imaging is established,which can predict the imaging results and guide the design of pinhole cameras.