High-energy time-resolved electron diffraction

Abstract

This chapter reviews the application of relativistic energy ultrashort electron beams to the direct investigation of structural changes in matter at atomic length scale with sub-picosecond (sub-ps) resolution by time-resolved electron diffraction(ED) time-resolvedelectron diffraction. There are many benefits of using higher-energy electron beams for time-resolved electron scattering instrumentation, due mainly to the space charge force suppression at relativistic energies, which enables more intense and shorter electron bunches. Speed-of-light probes, higher penetration, and shorter de Broglie wavelength are other advantages associated with MeV electron energy. The use of MeV beams for electron scattering demands excellent beam quality in both the transverse and longitudinal phase spaces, i.e., an exquisitely high six-dimensional(6-D) brightness. Expertise from the low-energy microscopy and diffraction community has converged with advances made in relativistic electron sources for high-energy particle accelerators and fourth-generation synchrotron light sources in the effort to create and deliver electron beams with these characteristics.