Novel laboratory spectrometer for pump-probe NEXAFS spectrometry of bio-molecules in solution

NEXAFS（近边X射线吸收精细结构）光谱仪的拟议开发旨在促进溶液中生物分子的时间分辨分析。本文以叶绿素铜（CuChl）为模型体系，探讨光合色素-蛋白质复合物的结构与功能关系。此外，独立于大规模facilities的泵浦探测实验的可能性将showed.The概念是基于一个激光产生的等离子体（LPP）源的软X射线区域，这是由申请人开发的，高效率的反射波带板具有高能量分辨率，一个大规模的CCD相机和解决方案的传输液体细胞。反射波带板的设计以及液体池的开发是拟议项目的一部分。光谱仪将针对CuChl的成分进行优化（C、O、N的K吸收边和Cu的LIII边），提供具有高光谱分辨率的NEXAFS光谱（E/DE~1000），在LPP源的几个单脉冲中的高信噪比（SNR~100）。因此，整个装置将使得能够在实验室中研究溶液中的生物样品，到目前为止，这必须在同步辐射设施中进行。NEXAFS光谱仪将在透射模式下工作，从而便于在线监测测量过程中的退化过程。此外，为了获得有关光学禁戒跃迁的信息，将使用光学泵浦和探测软X射线脉冲的变化来进行X射线光学双共振（XODR）研究。为此，将在装置中实现泵浦通道。新型光谱仪可以实现时间分辨测量，作为适合于fs光谱的光学元件。为了实现fs时间尺度，光谱仪可以与其他源一起使用，例如与Max-Born-Institute合作的HHG源。

The proposed development of a NEXAFS (Near edge x-ray absorption fine structure) spectrometer aims to facilitate time-resolved analysis of bio-molecules in solution. The structure-function relationship of photosynthetic pigment-protein complexes will be explored with the help of the model system copper chlorophyllin (CuChl). Additionally the possibility of pump-probe experiments independent on large scale facilities will be shown.The concept is based on a laser-produced plasma (LPP) source for the soft x-ray region which was developed by the applicant, highly efficient reflections zone plates with high energetic resolution, a large scale CCD camera and a transmission liquid cell for solutions. The design of the reflection zone plates as well as the development of the liquid cell is part of the proposed project.The spectrometer will be optimized for the components of CuChl (K absorption edges of C, O, N, and LIII edge of Cu), delivering NEXAFS spectra with high spectral resolution (E/DE~1000), high signal-to-noise ratio (SNR~100) in a few single pulses of the LPP source.The whole setup will thus enable the investigations of biological samples in solution in the laboratory, which up until now had to be performed at synchrotron radiation facilities. The NEXAFS spectrometer will operate in transmission mode, thus, facilitating on-line monitoring of degradation processes during measurements.In addition, to gain information about optically forbidden transitions X-ray optical double resonance (XODR) investigations will be performed by using an optical pump and probing the changes with the soft X-ray pulse. For this purpose a pump channel will be implemented in the setup.The novel spectrometer enables time-resolved measurements, as the optical element if suited for fs-spectroscopy. For the realization of fs-time scales the spectrometer can be used with other sources, for example HHG sources in cooperation with the Max-Born-Institute.