Figure 1
From: Following the dynamics of matter with femtosecond precision using the X-ray streaking method
X-ray streaking principle.
Diffraction gratings are used to create a multiple split-and-delay line. The upstream X-ray lens 1 focuses the XFEL beam onto the sample. The undiffracted (direct) beam serves as a pump and can be attenuated and focused independently by X-ray lens 2. The beams diffracted upwards by the splitter gratings Sn are redirected towards the sample by the recombiner gratings Rn and probe the pumped sample region with defined delays. The beams diffracted downwards by Sn are steered to a region of the sample that is 100 μm below the pump beam (see inset) to provide reference signals of the unpumped response on the very same shot. All beams are recorded separately on a detector array. Only three delayed beam pairs are shown for simplicity. The sample's scattering plane is chosen perpendicular to that of the gratings, in order to minimize coupling of the scattering angles.
