For the electron beam with the energy 20MeV, the emmitance 1 5πmm·mrad, the beam length 200fs and the electric charge 50pC, the THz radiation with the horizontal linear polarization or the circular polarization of the maximum flux density of 2×10 9 photons/mm 2/0 1%bw can be obtained at the distance 1m from the center of the undulator with 0 6m length.
It was shown that the flux density of the infrared and far-infrared transition undulator radiation of the SSRF U9.0 was high (e.g., the maximum flux density might reach 35x1013 photons/(s·mrad2· BW), collecting angle φ =0.23mrad, and the effects of beam energy spreed, emittance and magnetic field errors on the radiation flux density were small.
The influence of the adiabatic-magnetic-field distribution at the entrance of wiggler on the output power, gain, and efficiency in a free-electron laser is investigated in terms of nonlinear simulation.
We have developed a bifilar helix wiggler used in a Raman free-electron-laser, and have measured its operating characteristics. By using this wiggler as a pump source, we have obtained free-electron laser radiation and oarried out preliminary parametric studies.
We have made numerical calculation for the iron-ring wiggler used in our free-electron laser based on stimulated Raman soattering. The theoretical results were borne out by experimental measurements. By using this wriggler together with a guiding magnetic tield as the pumping source, we have obtained free-electron laser radiation.