Focusing x-ray free-electron-laser beams for imaging and creating extreme conditions in matter

• Applicant: Professor Dr. Christian Schroer
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 225455836

With their high spectral peak brightness, their short and tunable wavelength, and short pulse duration (< 100 fs), x-ray free-electron lasers are ideal to investigate fast processes in condensed matter. However, fast processes in matter involve also short length scales, requiring both high resolution spatially and temporally. In addition, the large penetration depth of x-rays and the high peak power allow one to deposit homogeneously a high energy density in small objects, generating extreme states of matter. Both high-resolution x-ray imaging and the heating of the sample require focusing the XFEL beam to 100 nm and below. The project aims at generating and characterizing short-pulse nanobeams by focusing the XFEL by refractive x-ray lenses, implementing time resolved nanoimaging techniques for matter in extreme conditions at the Linac Coherent Light Source at SLAC, and at applying these new techniques to characterizing shockwaves in a laser-heated aluminum target. In this way, we expect to measure the velocity and density in the shockfront, giving access to the density of states under these extreme conditions. In addition, the focused XFEL beam is used to create matter in extreme conditions by isochoric heating of small objects (e. g., metallic clusters) and to image them in states with high pressure and high temperature.

• DFG Programme: Research Grants
• International Connection: USA
• Participating Person: Dr. Andreas Schropp