Do Alexandre, Pickworth Louisa A, Kozioziemski Bernard J, Angulo Adrianna M, Hall Gareth N, Nagel Sabrina R, Bradley David K, Mccarville Tom, Ayers Jay M
Appl Opt. 2020 Dec 1;59(34):10777-10785. doi: 10.1364/AO.408569.
The study of Rayleigh-Taylor (RT) and Richtmyer-Meshkov (RM) instabilities in a planar geometry at high energy densities at the National Ignition Facility (NIF) requires high spatial resolution imaging. We demonstrate the potential of Fresnel zone plates (FZPs) to achieve resolution that would unlock such studies. FZPs are circular aperiodic gratings that use diffraction to focus x rays and produce an image with high spatial resolution. Taking into account the NIF's challenging environment, we have designed a specific array of five FZPs for a zinc backlighter to take a radiograph of a target with 9 keV x rays. We measured a mean resolution for the FZP of 1.9µ±0.5µ and a ±1 depth of focus at an x-ray calibration facility as well as a 2.3µ±0.4µ resolution on a resolution wire mesh shot on the NIF. We also performed an in-depth analysis of the image quality to assess the capability to resolve the small features present in RT and RM instabilities.
在国家点火装置（NIF）中，对平面几何结构下高能量密度的瑞利 - 泰勒（RT）和里希特迈尔 - 梅什科夫（RM）不稳定性进行研究需要高空间分辨率成像。我们展示了菲涅耳波带片（FZP）实现能够开启此类研究的分辨率的潜力。菲涅耳波带片是圆形非周期光栅，利用衍射来聚焦X射线并产生具有高空间分辨率的图像。考虑到NIF具有挑战性的环境，我们为锌背光源设计了一个由五个菲涅耳波带片组成的特定阵列，用于用9keV的X射线拍摄靶标的射线照片。我们在X射线校准设施中测量了菲涅耳波带片的平均分辨率为1.9µ±0.5µ以及±1的焦深，并且在NIF上对分辨率金属丝网拍摄时测量到分辨率为2.3µ±0.4µ。我们还对图像质量进行了深入分析，以评估分辨RT和RM不稳定性中存在的小特征的能力。
