Advances in X-ray laser sources have paved the way to relativistic attosecond X-ray laser pulses and opened up the possibility of exploring high-energy-density physics with this technology. With particle-in-cell simulations, we investigate the interaction of realistic metal crystals with relativistic X-ray laser pulses of parameters that will be available in the near future. A wakefield of the order of TV/cm is excited in the crystal and accelerates trapped electrons stably even though the wakefield is locally modulated by the crystal lattice. Electron injection either occurs at the sharp crystal–vacuum boundary or is controlled by coating the crystal with a high-density film. High-repetition-rate attosecond (20 as) monoenergetic electron beams of energy 125 MeV, charge 100 fC, and emittance 1.6 × 10−9 m rad can be produced by shining MHz X-ray laser pulses of energy 2.1 mJ onto coated crystals several micrometers thick. Such a miniature crystal accelerator, which has high reproducibility and allows sufficient control of the parameters of the electron beams, greatly expands the applications of X-ray free electron lasers. For example, it could serve as an ideal electron source for ultrafast electron diffraction and ultrafast electron microscopy to achieve attosecond resolution.

中文翻译：

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强X射线激光驱动晶体产生高重复率几阿秒高质量电子束

X 射线激光源的进步为相对论阿秒 X 射线激光脉冲铺平了道路，并开辟了利用该技术探索高能量密度物理的可能性。通过细胞内粒子模拟，我们研究了现实金属晶体与将在不久的将来可用的参数的相对论 X 射线激光脉冲之间的相互作用。TV/cm 量级的尾场在晶体中被激发并稳定地加速被俘获的电子，即使尾场是由晶格局部调制的。电子注入要么发生在尖锐的晶体 - 真空边界处，要么通过用高密度薄膜涂覆晶体来控制。高重复率阿秒 (20 as) 单能电子束，能量为 125 MeV，电荷为 100 fC，发射率为 1。通过将能量为 2.1 mJ 的 MHz X 射线激光脉冲照射到几微米厚的涂层晶体上，可以产生 6 × 10−9 m rad。这种具有高重现性和对电子束参数充分控制的微型晶体加速器，极大地扩展了X射线自由电子激光器的应用。例如，它可以作为超快电子衍射和超快电子显微镜的理想电子源，以实现阿秒分辨率。