Temporal X-ray Reconstruction using Temporal and Spectral Measurements at LCLS

摘要

Schematic of the measurement layout. An electron beam is sent through an FEL undulator where it produces X-ray radiation. Downstream of the FEL undulator, a horizontally deflecting TDS maps the longitudinal position to the horizontal. Additionally, a vertically deflecting dipole is used to separate the X-ray photons and the electrons and to relate the vertical bunch coordinate to the energy of the electrons. The longitudinal phase space density can then be measured using a screen. From these measurements it is possible to determine the temporal X-ray pulse profile. The X-rays are sent through a high-resolution spectrometer, where the power spectrum can be measured. Both measurements are combined for the temporal reconstruction of a photon pulse.