Technology of the ultra-fast pulse and high-power FELs driven by a superconducting rf linac

Minehara, Eisuke

We have developed free-electron lasers driven by a superconducting rf linac to demonstrate a powerful and efficient FEL, and the prototype of the FEL has successfully lased to get 0.1kW as the world-strongest FEL average power in February 1998. Two years after the first lasing, the second world-records of ultra-fast pulse of 250fs, efficiency of 7%, and average and peak power of 2.34kW and 1GW at 22 micron have successfully been obtained using a well-improved FEL and superconducting rf linac driver. The breakthrough of ultra-short pulse, efficiency and power in FELs has been realized using the improved driver performance of high density current and high-quality acceleration, and a discovery of sustained superradiance FEL oscillation. Resultantly, we have been successfully able to demonstrate high-efficiency larger than the theoretical limit and ultra-fast pulse of 3.4cycles, and 250fs. In the text, the novel technology of FELs driven by a superconducting rf linac will be briefly reported.