Birnsteinova Sarlota, Ferreira de Lima Danilo E, Sobolev Egor, Kirkwood Henry J, Bellucci Valerio, Bean Richard J, Kim Chan, Koliyadu Jayanath C P, Sato Tokushi, Dall'Antonia Fabio, Asimakopoulou Eleni Myrto, Yao Zisheng, Buakor Khachiwan, Zhang Yuhe, Meents Alke, Chapman Henry N, Mancuso Adrian P, Villanueva-Perez Pablo, Vagovič Patrik
European XFEL GmbH, Schenefeld, Germany.
Synchrotron Radiation Research and NanoLund, Lund University, Lund, Sweden.
J Synchrotron Radiat. 2023 Nov 1;30(Pt 6):1030-1037. doi: 10.1107/S1600577523007336. Epub 2023 Sep 20.
The high pulse intensity and repetition rate of the European X-ray Free-Electron Laser (EuXFEL) provide superior temporal resolution compared with other X-ray sources. In combination with MHz X-ray microscopy techniques, it offers a unique opportunity to achieve superior contrast and spatial resolution in applications demanding high temporal resolution. In both live visualization and offline data analysis for microscopy experiments, baseline normalization is essential for further processing steps such as phase retrieval and modal decomposition. In addition, access to normalized projections during data acquisition can play an important role in decision-making and improve the quality of the data. However, the stochastic nature of X-ray free-electron laser sources hinders the use of standard flat-field normalization methods during MHz X-ray microscopy experiments. Here, an online (i.e. near real-time) dynamic flat-field correction method based on principal component analysis of dynamically evolving flat-field images is presented. The method is used for the normalization of individual X-ray projections and has been implemented as a near real-time analysis tool at the Single Particles, Clusters, and Biomolecules and Serial Femtosecond Crystallography (SPB/SFX) instrument of EuXFEL.
与其他X射线源相比，欧洲X射线自由电子激光（EuXFEL）的高脉冲强度和重复率提供了卓越的时间分辨率。结合兆赫兹X射线显微镜技术，它为在需要高时间分辨率的应用中实现卓越的对比度和空间分辨率提供了独特的机会。在显微镜实验的实时可视化和离线数据分析中，基线归一化对于诸如相位恢复和模态分解等进一步处理步骤至关重要。此外，在数据采集期间获取归一化投影在决策中可以发挥重要作用，并提高数据质量。然而，X射线自由电子激光源的随机性质阻碍了在兆赫兹X射线显微镜实验中使用标准的平场归一化方法。在此，提出了一种基于动态演化平场图像主成分分析的在线（即近实时）动态平场校正方法。该方法用于单个X射线投影的归一化，并已在EuXFEL的单粒子、团簇和生物分子以及串行飞秒晶体学（SPB/SFX）仪器上实现为近实时分析工具。
