A seeded FEL driven by a linac based on super conducting cavities, generating 108–1010 coherent photons per shot at 2–5 keV with 0.2–1 MHz of repetition rate, can address the need of a source devoted to fine analysis of matter using the linear spectroscopy technique. The seeding scheme described hereafter is a multi-stage cascade upshifting the radiation frequency by a factor 20–40. The x-ray range can be achieved with a seed constituted by a coherent flash in the extreme ultraviolet range provided by an FEL oscillator operating at 12–14 nm. The whole chain of x-ray generation is described by means of start-to-end three-dimensional simulations.

中文翻译：

---

由极紫外自由电子激光振荡器提供种子的相干、高重复率嫩 X 射线自由电子激光器

由基于超导腔的直线加速器驱动的种子 FEL，在 2-5 keV 和 0.2-1 MHz 的重复率下每次发射产生 108-1010 个相干光子，可以满足使用线性光谱技术。下文描述的播种方案是将辐射频率上移 20-40 倍的多级级联。X 射线范围可以通过由在 12-14 nm 工作的 FEL 振荡器提供的极紫外范围内的相干闪光构成的种子来实现。整个 X 射线生成链是通过从头到尾的 3 维模拟来描述的。