The structure and dynamics of isolated nanosamples in free flight can be directly visualized via single-shot coherent diffractive imaging using the intense and short pulses of X-ray free-electron lasers. Wide-angle scattering images even encode three-dimensional morphological information of the samples, but the retrieval of this information remains a challenge. Up to now, effective three-dimensional morphology reconstructions from single shots were only achieved via fitting with highly constrained models, requiring a priori knowledge about possible geometrical shapes. Here we present a much more generic imaging approach. Relying on a model that allows for any sample morphology described by a convex polyhedron, we reconstruct wide-angle diffraction patterns from individual silver nanoparticles. In addition to known structural motives with high symmetries, we retrieve imperfect shapes and agglomerates which were not accessible previously. Our results open new routes towards true 3D structure determination of single nanoparticles and, ultimately, 3D movies of ultrafast nanoscale dynamics.

翻译：自由飞行中孤立的纳米样本的结构和动态可以通过单发、一致的光学成像直接视觉化,使用X射线自由电子激光的紧短脉冲,直接视觉化。宽角散射图像甚至编码了样品的三维形态信息,但这种信息的检索仍是一个挑战。到目前为止,从单一镜头中有效的三维形态重建只能通过安装高度受限制的模型来实现,这需要先验地了解可能的几何形状。在这里,我们展示了一种更通用的成像方法。依靠一种模型,这种模型可以让由锥形聚光线描述的任何样本形态发生,我们从单个银纳米粒子中重建宽角的折射模式。除了已知的高对称结构动机外,我们还检索了以前无法接触到的不完美的形状和巨石。我们的结果打开了通往单一纳米粒子和最终超快速纳米动态的3D电影的真正3D结构确定的新路径。