Exploiting X-ray Free Electron Lasers (XFELs) for Extreme Conditions Science
The creation of extreme states of matter via dynamic compression dates back to the Manhattan Project. Since then, high-energy lasers or even nuclear explosions have been used to generate pressures into the Gbar range where densities of kg/cc are crated. However, the lack of suitably bright x-ray sources has largely prevented the study of such extreme states using x-ray scattering techniques. XFELs such as the LCLS at the SLAC National Laboratory deliver 1012 photons in sub-100 fs pulses, and have a peak brilliance a billion times higher than any synchrotron. They are thus ideally suited to the study of extreme states of matter that may only exist for picoseconds or nanoseconds. In this talk I will discuss some recent results we have obtained at the LCLS on dynamically-compressed Bi, Sb and Sc [1-4], and then look to what will be possible on the new European-XFEL in Hamburg using both static and dynamic compression. An EPSRC funding opportunity for taking part in Euro-XFEL experiments will also be described.
 Recovery of Metastable Dense Bi Synthesized by Shock Compression, M.G. Gorman et al, Applied Physics Letters (To be published).
 Femtosecond Diffraction Studies of Solid and Liquid Phase Changes in Shock-Compressed Bismuth, M.G. Gorman et al, Scientific Reports 8, 16927 (2018).
 Ultrafast X-Ray Diffraction Studies of the Phase Transitions and Equation of State of Scandium Shock Compressed to 82 GPa, R. Briggs et al, PRL 118, 025501 (2017).
 Direct Observation of Melting in Shock-Compressed Bismuth With Femtosecond X-ray Diffraction, M.G. Gorman et al, PRL 115, 095701 (2015).
All are welcome to attend. For information about the CES seminar contact Sven.Friedemann@bristol.ac.uk