FEL system for gamma–gamma collider at TESLA

The present paper contains the results of optimization of the free electron laser for the gamma–gamma collider at TESLA. A superconducting linear accelerator, similar to the TTF (TESLA Test Facility) accelerator, produces a driving electron beam for the FEL. The MOPA FEL scheme is studied when the radiation from a master oscillator is amplified in the FEL amplifier with tapered undulator. The FEL produces a radiation of TW level with a wavelength of 1 μm. Optimization of the FEL amplifier is performed with a three-dimensional, time-dependent simulation code FAST.