Location of the correlation islands deduced from figure 2

Table 1. Location of the correlation islands deduced from figure 2. Their assignments are confirmed by comparison with theoretical predictions. The Ekin values given correspond to specific sequences of the multi-ionization processes as labelled in bold in the third column. To denote the Ne 1sr2st2pk electron configurations, the notation rtk is used. Abstract We report on a detailed investigation into the electron emission processes of Ne atoms exposed to intense femtosecond x-ray pulses, provided by the Linac Coherent Light Source Free Electron Laser (FEL) at Stanford. The covariance mapping technique is applied to analyse the data, and the capability of this approach to disentangle both linear and nonlinear correlation features which may be hidden on coincidence maps of the same data set is demonstrated. Different correction techniques which enable improvements on the quality of the spectral features extracted from the covariance maps are explored. Finally, a method for deriving characteristics of the x-ray FEL pulses based on covariance mapping in combination with model simulations is presented.

表1 由图2推导得到的关联岛（correlation islands）的位置。通过与理论预测结果比对，可确认上述关联岛的属性归属。文中给出的Ekin值对应第三列以粗体标注的多电离过程的特定序列。针对Ne原子的1s^r2s^t2p^k电子组态，采用rtk标记法进行表述。
摘要 本研究针对氖（Ne）原子在斯坦福直线加速器相干光源自由电子激光（Linac Coherent Light Source Free Electron Laser, FEL）提供的强飞秒X射线脉冲辐照下的电子发射过程展开了详细探究。本研究运用协方差映射（covariance mapping）技术对实验数据进行分析，证实该方法能够分离出隐藏于同一数据集符合映射图（coincidence maps）中的线性与非线性关联特征。本研究还探索了多种可提升协方差映射图提取光谱特征质量的校正技术。最后，本文提出了一种结合协方差映射与模型模拟，以获取X射线自由电子激光脉冲特性的方法。