论文标题
欧洲XFEL的Photon Shot-Noise Limit
Photon shot-noise limited transient absorption soft X-ray spectroscopy at the European XFEL
论文作者
论文摘要
飞秒瞬态X射线吸收光谱（XAS）是一种非常有前途的技术，可以在X射线游离电子激光器（FELS）中使用，以研究材料和能量研究的不平衡动力学。在这里，我们提供了用于在欧洲X射线无电子激光器（EUXFEL）的光谱与相干散射（SCS）仪器上可用的软X射线的专用设置。它由传输中用于创建传入光束的三个副本的横梁裂开离轴区域板（BOZ）组成，该光束用于通过激发和未启用的样品来测量传输强度，并监视输入强度。由于这三个强度信号是逐射击并同时检测到的，因此该设置允许对变速箱进行标准化的射击分析。对于光子检测，采用了DSSC成像检测器，该检测器能够在FEL爆发期间以4.5 MHz帧速率记录800张图像，并允许接近光子射击量限制。我们会查看设置及其功能，以及提供给用户提供的在线和离线分析工具。
Femtosecond transient soft X-ray Absorption Spectroscopy (XAS) is a very promising technique that can be employed at X-ray Free Electron Lasers (FELs) to investigate out-of-equilibrium dynamics for material and energy research. Here we present a dedicated setup for soft X-rays available at the Spectroscopy & Coherent Scattering (SCS) instrument at the European X-ray Free Electron Laser (EuXFEL). It consists of a beam-splitting off-axis zone plate (BOZ) used in transmission to create three copies of the incoming beam, which are used to measure the transmitted intensity through the excited and unexcited sample, as well as to monitor the incoming intensity. Since these three intensity signals are detected shot-by-shot and simultaneously, this setup allows normalized shot-by-shot analysis of the transmission. For photon detection, the DSSC imaging detector, which is capable of recording up to 800 images at 4.5 MHz frame rate during the FEL burst, is employed and allows approaching the photon shot-noise limit. We review the setup and its capabilities, as well as the online and offline analysis tools provided to users.
