Electron beamline design for the Los Alamos National Laboratory 1kW FEL

This paper describes the electron beam simulations for a 1 kW average power FEL. The experiment utilizes the existing AFEL accelerator. An expected 6% total efficiency of electron beam power to optical power gives 17 kW of electron beam power for I kW of optical power. A constraint on the beamline design is that the FEL electron beamline and optical components must fit on the existing AFEL 6 ft long optical table. The components include electron beam diagnostics, a 2 m long wiggler, bending magnets, and optical feedback components. The electron beam design point is 300 A peak current. 17 MeV energy, 7.5 pi mm-mrad effective normalized rms emittance and 6 nC micropulse charge. The electron beamline will have greater than 99% transmission. The wiggler will have weak (natural) two-plane focusing to maintain the electron beam size in the long wiggler. The beamline after the wiggler has to transport a beam with a 14-18 MeV energy spread and an average energy of 16 MeV.