S.G. Biedron, H. P. Freund, X. Wang, and L-.H. Yu
Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439; Science Applications Corp., McLean, Virginia 22102; Brookhaven National Laboratory, Upton, NY 11973
We have previously performed rigorous analyses of the nonlinear harmonics in self-amplified spontaneous emission (SASE) free-electron lasers (FELs) using a 3D simulation code. To date, we have presented only preliminary results of these higher harmonics resulting in the high-gain harmonic generation (HGHG) process. A single-pass, high-gain FEL experiment based on the HGHG theory is underway at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory (BNL) in collaboration with the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). Using the above experiment's design parameters, the specific case of the harmonic output from the HGHG experiment will be examined using a 3D simulation code. The sensitivities of nonlinear harmonic output for this HGHG experiment and a SASE configuration (with the same electron beam and radiative section) as functions of emittance, energy spread, and peak current in both cases, and for the dispersive section strength and input seed power in the HGHG case, will be presented.
