Speaker: Agostino Marinelli, Accelerator Directorate
Program Description
Two color x-ray pulses have received considerable attention at fourth generation light sources, as they enable a wide range of new experiments, from imaging of biological molecules to time resolved studies of plasmas and atomic systems.
To extend the two color capabilities of the LCLS, double bunch operation has been recently demonstrated and successfully delivered to user experiments. In this scheme two closely spaced bunches are generated at the cathode and accelerated off-crest to two different energies. The resulting bunch train radiates a two-color x-ray pulse in the undulator.
The distinct advantage of this approach is the possibility of using the entire undulator length on both colors, thus allowing applications that require high-intensity and/or self-seeding with a large spectral separation (up to ~1-2%).
Furthermore, the relative time delay and energy difference of the two pulses are tunable independently, making this scheme a good candidate for x-ray pump/x-ray probe experiments.
We review the experimental results and discuss our operational experience with user experiments.
