Research Equipment Grant: Diagnostics of Hot Capillary Discharge Plasmas for Efficient Soft X-Ray Sources

美国科罗拉多州立大学电子工程系提出了一种x射线条纹相机/柱状光谱仪组合的构建，作为一种强大的诊断工具，用于开发基于快速毛细管放电的高效新型x射线辐射源。重要的技术和科学应用需要开发高效和紧凑的x射线辐射源。科罗拉多州立大学最近进行的实验结果表明，毛细管通道的极快放电激励，其上升时间为10ns数量级，可以产生电子温度为几百eV的致密等离子体柱，其电流比在太瓦脉冲功率机中产生热等离子体的电流小一个数量级以上。这种通过直接放电激发有效产生小直径（=200um）等离子体柱的能力为实现紧凑高效的软x射线激光器提供了一条新的途径。此外，将电储存的能量直接转移到可再生的小直径热毛细管等离子体中，可以产生紧凑而有效的非相干x射线源。该仪器将毛细管放电发出的软x射线成像成具有高空间分辨率和光谱分辨率的平面场。放置在柱头摄谱仪焦平面上的x射线照相机将提供必要的时间分辨率，以便在一次拍摄中绘制软x射线辐射的演变图。这种组合将构成一种强大的仪器来识别线放大以及表征这些有前途的等离子体的动力学，这些等离子体目前比激光产生的等离子体要少得多。提出的仪器的新设计还将使其快速重新配置为两种额外的互补操作模式，以产生：a)同时获得的空间分辨光谱集和b)电子记录的等离子体针孔图像。* * *

9412106 Rocca The Department of Electrical Engineering at Colorado State University proposed the construction of an x-ray streak camera/stigmatic spectrograph combination to be utilized as a powerful diagnostics tool in the development of efficient new sources of x-ray radiation based on fast capillary discharges. Important technological and scientifiv applications require the development of efficient and compact sources of x-ray radiation. Results of recent experiments conducted at Colorado State University show that very fast discharge excitation of capillary channels with risetimes of the order of 10ns can generate dense plasma columns with electron temperatures of a few hundred eV utilizing currents that are more than an order of magnitude smaller than those utilized to generate hot plasmas in Terawatt pulse power machines. Such capability for efficiently generating plasma columns of small diameter (=200um) by direct discharge excitation could provide a new route towards compact and efficient soft x-ray lasers. Also, the direct transfer of electrically stored energy into reproducible hot capillary plasmas of small diameters could result in a compact and efficient source of incoherent x-rays. The proposed instrument will image into a flat field with high spatial and spectral resolution the soft x-ray radiation emitted by the capillary discharge. An x-ray camera, placed in the focal plane of the stigmatic spectrograph will provide for temporal resolution necessary to map the evolution of the soft x-ray radiation in a single shot. This combination will constitute a powerful instrument to identify line amplification as well to characterize the dynamics of these promising plasmas which are presently significantly less understood than laser created plasmas. The novel design of the proposed instrument will also for rapidly reconfiguring it into two additional complementary modes of operation to generate: a) sets of simultaneously acquired spatially resolved spectra and b) electronically reco rded pinhole images of the plasma. ***