We present the experimental end-station TRIXS dedicated to time-resolved soft x-ray resonant inelastic x-ray scattering (RIXS) experiments on solid samples at the free-electron laser FLASH. Using monochromatized ultrashort femtosecond XUV/soft x-ray photon pulses in combination with a synchronized optical laser in a pump-probe scheme, the TRIXS setup allows measuring sub-picosecond time-resolved high-resolution RIXS spectra in the energy range from 35 eV to 210 eV, thus spanning the M-edge (M₁ and M_2,3) absorption resonances of 3d transition metals and N_4,5-edges of rare earth elements. A Kirkpatrick–Baez refocusing mirror system at the first branch of the plane grating monochromator beamline (PG1) provides a focus of (6 × 6) μm² (FWHM) at the sample. The RIXS spectrometer reaches an energy resolution of 35–160 meV over the entire spectral range. The optical laser system based on a chirped pulse optical parametric amplifier provides approximately 100 fs (FWHM) long photon pulses at the fundamental wavelength of 800 nm and a fluence of 120 mJ/cm² at a sample for optical pump-XUV probe measurements. Furthermore, optical frequency conversion enables experiments at 400 nm or 267 nm with a fluence of 80 and 30 mJ/cm², respectively. Some of the first (pump-probe) RIXS spectra measured with this setup are shown. The measured time resolution for time-resolved RIXS measurements has been characterized as 287 fs (FWHM) for the used energy resolution.

中文翻译：

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在软X射线自由电子激光器FLASH上进行飞秒时间分辨共振非弹性X射线散射实验的TRIXS终端站

我们介绍了专用于时间分辨软X射线共振非弹性X射线散射（RIXS）实验的终端设备TRIXS，该实验在自由电子激光FLASH上对固体样品进行。在泵浦探针方案中，通过使用单色超短飞秒XUV /软X射线光子脉冲与同步光学激光器相结合，TRIXS设置可以测量亚皮秒时间分辨的高分辨率RIXS光谱，能量范围为35 eV至210 eV，因此跨越3d过渡金属的M边缘（M ₁和M _2,3）吸收共振和稀土元素的N _4,5边缘。在平面光栅单色射束线（PG1）的第一支路A帕特里克-贝兹重聚焦镜系统提供的（6×6）的聚焦μ米样品²（FWHM）。RIXS光谱仪在整个光谱范围内的能量分辨率达到35–160 meV。基于a脉冲光参量放大器的光学激光系统在800 nm的基波波长下提供大约100 fs（FWHM）长的光子脉冲，并在样品上提供了120 mJ / cm ²的注量，用于光泵浦-XUV探针测量。此外，光频率转换使得能够分别以80和30 mJ / cm ²的通量在400 nm或267 nm进行实验。显示了使用此设置测量的一些第一（泵探针）RIXS光谱。对于时间分辨的RIXS测量，所测量的时间分辨率已表征为所用能量分辨率为287 fs（FWHM）。