Wire, hybrid, and laser-cut X-pinches as Talbot–Lau backlighters for electron density diagnostics
Wire, hybrid, and laser-cut X-pinches as Talbot–Lau backlighters for electron density diagnostics
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DOI：
10.1088/1361-6587/ac4b95
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发表时间：
2022-01
影响因子：
2.2
通讯作者：
M. Valdivia;G. Collins IV;F. Conti;F. Beg
中科院分区：
文献类型：
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作者：
M. Valdivia;G. Collins IV;F. Conti;F. Beg
Talbot-Lau x射线偏转仪（TXD）为高能量密度物理实验提供了基于折射成像的方法，因此，它的研究和发展目标是诊断与惯性约束和磁线性惯性聚变相关的等离子体。x- pinch以可靠地产生快速（~ 1 ns），小（~ 1 μ m） x射线源而闻名，在小型电流驱动发生器上驱动，用于烧蚀结构和内爆研究（~ 200 kA, 150 ns），作为TXD的潜在背光源。考虑到不同的X-pinch结构作为x射线产生负载各有优缺点，研究了三种不同的铜X-pinch结构：导线X-pinch、混合X-pinch和激光切割X-pinch。根据8 keV TXD系统的特定背光源要求：空间和时间分辨率、光源数量、发射时间、光谱和再现性，对每种配置的Cu k壳发射进行了表征和分析。提出了今后实验改进和应用的建议。从通过TXD获得的moir<s:1>图像中提取静态物体的电子密度。这使得计算静态样品的质量密度在激光切割x -捏缩期望值的4%以内，这被发现是TXD的最佳x -捏缩配置，因为它们具有高重复性，小源尺寸（≤5µm），持续时间短（~ 1 ns），峰值功率高达106 W，接近8 keV光子能量。等离子体负荷首次使用激光切割X-pinch背光通过TXD成像。实验图像与x射线波前传播代码的模拟结果进行了比较，结果表明TXD可以作为一种基于x射线折射的诊断方法来诊断密集的z箍缩载荷。描述了在脉冲功率环境下塔尔博特-劳干涉诊断的未来计划。
Talbot–Lau x-ray deflectometry (TXD) enables refraction-based imaging for high-energy-density physics experiments, and thus, it has been studied and developed with the goal of diagnosing plasmas relevant to inertial confinement and magnetic liner inertial fusion. X-pinches, known for reliably generating fast (∼1 ns), small (∼1 µm) x-ray sources, were driven on the compact current driver generator for ablation structure and implosion studies (∼200 kA, 150 ns) as a potential backlighter source for TXD. Considering that different X-pinch configurations have characteristic advantages and drawbacks as x-ray generating loads, three distinct copper X-pinch configurations were studied: the wire X-pinch, the hybrid X-pinch, and the laser-cut X-pinch. The Cu K-shell emission from each configuration was characterized and analyzed regarding the specific backlighter requirements for an 8 keV TXD system: spatial and temporal resolution, number of sources, time of emission, spectrum, and reproducibility. Recommendations for future experimental improvements and applications are presented. The electron density of static objects was retrieved from Moiré images obtained through TXD. This allowed to calculate the mass density of static samples within 4% of the expected value for laser-cut X-pinches, which were found to be the optimal X-pinch configuration for TXD due to their high reproducibility, small source size (⩽5 µm), short duration (∼1 ns), and up to 106 W peak power near 8 keV photon energy. Plasma loads were imaged through TXD for the first-time using laser-cut X-pinch backlighting. Experimental images were compared with simulations from the x-ray wave-front propagation code, demonstrating that TXD can be a powerful x-ray refraction-based diagnostic for dense Z-pinch loads. Future plans for Talbot–Lau interferometry diagnostics in the pulsed-power environment are described.