皮秒激光驱动的X射线源编码高分辨照相技术

Source-coded radiography technique with high spatial-resolution for X-ray source driven by ps-laser

为实现惯性约束聚变(ICF)内爆燃烧停滞阶段过程中最大压缩时刻的冷燃料面密度分布测量,设计了包含字母客体与针孔阵列的照相客体,通过同一发相同视角测量源分布与客体照相技术,首次建立了皮秒激光驱动的高能X射线源编码照相技术。通过星光Ⅲ实验研究,基于W丝阵靶照相的反演图像空间分辨率5.4μm±0.7μm;激光到X射线(50~200 keV)的能量转换效率,W丝阵靶5.4×10^(−4),与传统Au单丝靶的转换效率(4.8×10^(−4))一致。基于源编码照相解决了传统皮秒激光背光照相中空间分辨率与光源亮度不能兼顾的困难,为强背景干扰下提供高信噪比、高分辨率的ICF靶丸压缩背光图像提供了重要照相方式。

To measure the areal density distribution of cold fuel at the maximum compression time during the stagnation phase of implosion in inertial confinement fusion(ICF),we have established the ps-laser driven high-energy X-ray radiography using source-coded technique.This paper describes the design and employment of the object including character-object and pinhole array.Based on the object,the source distribution and the object radiography was obtained at the same shot and same angle of view,and therefore the source-coded radiography of pslaser driven X-ray has been established in experiments for the first time.From the experimental work on Xingguang-Ⅲ facility,the spatial resolution of the inversion image with W wire-array target is 5.4μm±0.7μm.The efficiency of converting laser energy to high-energy bremsstrahlung(50−200 keV)is 5.4×10^(−4) in W wire-array target and 4.8×10^(−4) in Au single-wire target,respectively.It is possible that the the source-coded radiography of ps-laser driven X-ray in this work could account for overcoming the balance between spatial resolution and brightness in traditional X-ray backlight by ps-laser.The source-coded radiography provides an important method for ICF implosion backlight to get high resolution high signal-to-noise ratio images under the strong background.