CAS Accelerator Seminars

MeV-UED: A Unique Tool for Total Scattering

by X.J. Wang (SLAC)

WBGB/019 (Paul Scherrer Institut)


Paul Scherrer Institut


X-ray Free Electron Laser (XFEL) revolutionized ultrafast science. One of the enabling technologies of XFEL is high-brightness electron source based on the photocathode RF gun. The MeV electrons produced by the photocathode RF gun also made it feasible for MeV ultrafast electron scattering [1-2].  MeV ultrafast electron scattering became a new frontier in ultrafast science due to its capability of following dynamics on femtoseconds scale with the high spatial resolution and sensitivity [3-4]. Furthermore, MeV electrons experience less multiple-scattering, and possess “real” flat Ewald-sphere; MeV ultrafast electron diffraction (MeV-UED) is an ideal tool to explore both structure and dynamics using total scattering technique. MeV-UED had broad and transformative impact on ultrafast science, such as the first 2-D materials ultrafast structure dynamics [5], light-induced transient states of quantum materials [6-7], the first direct imaging of fundamental chemical processes [8-9] and hydrogen bond dynamics in liquid water [10]. Recently, we have demonstrated the first operando experiment in ultrafast [11] and the first successful ultrafast visualization of incipient plasticity in dynamically compressed matter [12]. Total scattering has been explored by X-ray and Neutron scattering communities to study energy materials, the time-resolved total scattering enabled by MeV-UED make it feasible to image energy and charge follow in 2-D heterostructure [13] and revealing the intricate relation between dynamics and function of 2-D perovskite [14]. 

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For details contact Paolo Craievich