A Far-Infrared FEL for the Radiation Source ELBE


A Far-Infrared FEL for the Radiation Source ELBE

Grosse, E.; Lehnert, U.; Michel, P.; Schlenk, R.; Seidel, W.; Wolf, A.; Willkommen, U.; Wohlfarth, D.; Wünsch, R.

After successfully commissioning the mid‐infrared FEL (U27) and adjoining a second accelerator unit (up to 35 MeV) at ELBE we have modified our plan how to produce radiation in the far infrared.To ensure the continuous variation of the wavelength up to 150 microns we want to complement the U27 undulator by a permanent magnet undulator with a period of 100 mm (U100). The minimum gap of 24 mm and the hybrid construction consisting of Sm/Co magnets and soft iron poles ensures sufficient radiation resistance and allows rms undulator parameters up to 2.7. The large field variation allows us to cover the whole wavelength range by only two different electron energies (e.g. 20 and 35 MeV). To reduce the transverse beam size we use a partial waveguide which is 10 mm high and wide enough to allow free propagation inhorizontal direction. It spans from the last quadrupole in front of the undulator up to the downstream mirror and is somewhat longer than 8 m. To minimize the coupling losses between free propagation and the waveguide mode appropriate bifocal resonator mirrors will be sed. Detailed calculations and computer simulations predict an outcoupled laser power of roughly 35 W around 40 microns and 20 W at150 microns.

Keywords: undulator; free-electron laser; waveguide; radiation source ELBE

  • Poster
    27th Int. Free Electron Laser Conference, 21.-26.08.2005, Palo Alto, USA
  • Contribution to proceedings
    27th Free Electron Laser Conference, 21.-26.08.2005, Palo Alto, USA
    Proceedings of the 27th International Free Electron Laser Conference, 290-292

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Publ.-Id: 7584