针孔辅助点投影诊断方法实验研究

针孔辅助点投影背光成像是近几年国外新兴的等离子体诊断技术,在惯性约束聚变相关物理实验诊断中具有重要的应用前景.为验证这一诊断方法的实用性,在神光Ⅱ第九路平台上开展了演示实验.利用激光驱动平面Ti靶获得约4.7 keV的Ti K壳层X射线,在十几微米的针孔约束下作为次级点源并对Au栅格样品投影成像,并用CCD记录.实验成功获得了清晰的样品二维空间分辨的时间积分图像,空间分辨力优于16.1 μm.实验结果表明针孔辅助点投影具有较高的空间分辨力、较大的视场、较高的图像对比度,将成为瑞利泰勒不稳定性研究、激光状态方程研究等物理实验的重要诊断方法之一.

Experimental Research on Pinhole-Assisted Point Projection Diagnostic Scheme

Pinhole-assisted point projection (PAPP) backlight scheme is a newly developed diagnostic technique for laser-plasma experiments in foreign laboratories, which will play an important role in diagnostic experiments of inertial confinement fusion (ICF) physics. Experiments have been carried out on the additional beam of “Shenguang-Ⅱ” laser facility, to test the practicability of PAPP scheme. The K-shell X rays (～4.7 keV) emitted from laser-produced planar Ti targets pass through the pinhole aperture with diameter of 10～40 μm, then cast the shadow of the Au sample on CCD. Time-integrated two-dimensional (2D) pictures of the samples are obtained in the experiments with the resolution better than 16.1 μm. The merits, such as high resolution, large field-of-view, high contrast, have been found in the experimental results, and PAPP will become one of the most important diagnostic methods for Rayleigh-Taylor instability research, equation of state (EOS) research and so on.