利用多波长单色X射线成像技术绘制激光辐照氩气射流的电离状态图。

Mapping the ionization state of laser-irradiated Ar gas jets with multiwavelength monochromatic x-ray imaging.

作者信息

Kugland N L, Döppner T, Kemp A, Schaeffer D, Glenzer S H, Niemann C

机构信息

Department of Physics, University of California, Los Angeles, Los Angeles, California 90095, USA.

出版信息

Rev Sci Instrum. 2010 Oct;81(10):10E526. doi: 10.1063/1.3491221.

DOI:10.1063/1.3491221

PMID:21034054

Abstract

Two-dimensional monochromatic images of fast-electron stimulated Ar Kα and He-α x-ray self-emission have recorded a time-integrated map of the extent of Ar(≈6+) and Ar(16+) ions, respectively, within a high density (10(20) cm(-3) atomic density) Ar plasma. This plasma was produced by irradiating a 2 mm wide clustering Ar gas jet with an ultrahigh intensity (10(19) W/cm(2), 50 TW) Ti:sapphire laser operating at 800 nm. Spherically bent quartz crystals in the 200 (for Kα) and 201 (for He-α) planes were used as near-normal incidence reflective x-ray optics. We see that a large (830 μm long) region of plasma emits Kα primarily along the laser axis, while the He-α emission is confined to smaller hot spot (230 μm long) region that likely corresponds to the focal volume of the f/8 laser beam. X-ray spectra from a Bragg spectrometer operating in the von Hamos geometry indicate that the centroids of the Kα and He-α emission regions are separated by approximately 330 μm along the laser axis.

摘要

快速电子激发氩的Kα和氦的α射线自发射的二维单色图像，分别记录了高密度（原子密度为10²⁰ cm⁻³）氩等离子体中氩（≈6⁺）离子和氩（16⁺）离子范围的时间积分图。该等离子体是通过用波长为800 nm、超高强度（10¹⁹ W/cm²，50 TW）的钛宝石激光照射宽2 mm的团簇氩气射流产生的。在200平面（用于Kα）和201平面（用于氦的α射线）中的球形弯曲石英晶体被用作近垂直入射反射式X射线光学元件。我们发现，一个大的（长830μm）等离子体区域主要沿激光轴发射Kα射线，而氦的α射线发射局限于较小的热点区域（长230μm），该区域可能对应于f/8激光束的焦斑体积。在冯哈莫斯几何结构中运行的布拉格光谱仪的X射线光谱表明，Kα和氦的α射线发射区域的质心沿激光轴相距约330μm。