The electron beam is the lasing medium of a Free-Electron Laser (FEL). When driven to saturation, the high-gain FEL process leaves a measurable imprint in the electron beam longitudinal phase space (LPS, time-energy). In many FEL operation modes, there is an excellent time correlation between the FEL pulse and its imprint. After mapping time and energy coordinates to transverse coordinates by...
Pump and probe techniques utilizing high peak brightness X-ray free electron lasers (XFELs) are powerful tools for studying X-ray nonlinear optics, ultrafast X-ray matter interactions and subsequent ultrafast dynamics. Owning to the stochastical properties of the SASE X-ray pulses, ultrafast pump and probe experiment normally requires a precise characterization of the temporal properties of...
Recent years particular attention has been paid to X-ray pump-X-ray probe experiments enabling, for example, excitation of selective sites in a molecule or subshell in an atom with the pump pulse and monitoring its evolution with the probe. To mitigate the jitter of X-ray pulses produced independently (i.e. in two separate instruments), different X-ray free-electron lasers (XFELs) are...
