Demonstration of X-ray Thomson Scattering on Shenguang-Ⅱ Laser Facility

X-ray Thomson scattering technique for diagnosing dense plasma was demonstrated on Shenguang-Π laser facility.Laser plasma x-ray source of titanium He-α lines (～4.75keV),generated by laser beam (1.5kJ/527nm/2ns) heated titanium thin foil,was used as x-ray probe beam.The x-ray probe was then scattered by cold CH foam column of 1g/cm3 density.The scattered radiation at 90 was diffracted by polyethylene terephthalate (PET) crystal and recorded on x-ray charge-coupled device.Well-defined scattering spectra were obtained with good signal to noise ratio.     

利用平晶谱仪测量谱线波长的新方法

为了满足激光等离子体X射线波长测量的需要,在辅助光阑法的基础上,从理论上提出了一种用平面晶体谱仪确定波长的新方法.发展了改进的辅助光阑法来确定晶体面与记录面的交线到第一条辅助光阑的距离,并且利用某一条谱线的曲率得到记录面与晶体表面的夹角.这两个参量在一般的辅助光阑法中需借用参考谱线得到,而采用新的方法可在不使用任何参考谱线的情况下得到所有光谱线的波长.实际使用中通过增大光阑间的间距,根据不同的波长范围调节晶体与记录面的相对位置,可使波长的测量精度达1×10-3nm.     

氢（氘、氚）分子与低能氦原子（E=0.1eV）碰撞研究

对H2,D2,T2碰撞体系,采用Tang-Toennies势,用密耦方法求解散射方程,计算了E＝0.1eV时00－00,00－02,00－04分子转动激发分截面和角分布,并研究了原子与分子碰撞弹性分波截面和非弹性激发截面随量子数增加的变化规律。     

Spaced-Resolved Electron Density of Aluminum Plasma Produced by Frequency-Tripled Laser

1 Introduction X-ray spectra emitted from hot dense plasmas pro- vide an important diagnostic tool to infer local plasma parameters, particularly the ionization stage, density, and temperature [1]. Analysis of the emission spectra of highly stripped ions from laser-produced plasmas is potentially the most direct and reliable method for de- ducing the ultra-high-pressure plasma conditions. The development of the diagnostic methods for electron den- sity will produce important effect on the stud…     

A High-Efficiency X-Ray Crystal Spectrometer for X-Ray Thomson Scattering

Highly oriented pyrolitic graphite (HOPG) has high X-ray diffraction efficiency due to its unique mosaic crystal structure, and thus is very suitable for its application to X-ray Thomson scattering measurement of solid-density plasmas. In this article, by using the K-shell X-ray source from laser-produced Ti plasma, the properties of the HOPG spectrometer are characterized and compared with those of the flat Pentaerythritol (PET) spectrometer. The results show that the diffraction efficiency of the HOPG spectrometer under focusing condition is an order higher than that of the PET spectrometer, while the spectral resolution of the HOPG is about 320, high enough to be used in the measurement of X-ray Thomson scattering spectra.     

辐射不透明度实验技术研究

在“神光”Ⅱ强激光装置上,开展了辐射不透明度综合实验测量技术探索和相关物理问题的分解研究,并对部分新型诊断设备进行考核。实验的主要研究内容包括:(1)keV能区辐射吸收谱测量技术探索;(2)双点背光法辐射不透明度测量技术探索;(3)不透明度样品状态参数诊断技术探索。