Author: Duris, J.P.
Paper Title Page
TUP042 High Efficiency Lasing with a Strongly Tapered Undulator 478
  • J.P. Duris, P. Musumeci
    UCLA, Los Angeles, California, USA
  Funding: This work was supported by DOE grant DE-FG02-92ER40693, Defense of Threat Reduction Agency award HDTRA1-10-1-0073 and University of California Office of the President award 09-LR-04-117055-MUSP.
Typical electrical to optical energy conversion efficiencies for FELs are limited by the Pierce parameter to 10-3 or smaller. Undulator tapering schemes have enabled extraction of as much as 1 or 2% of the electron energy. Recently, the UCLA BNL helical inverse free electron laser (IFEL) experiment at ATF demonstrated energy doubling and acceleration of 30% of an electron beam from 52 to 93 MeV with a modest 1011 W power CO2 laser pulse. By reversing and retuning the undulator, the electrons may be violently decelerated, thereby transferring energy from the beam to the laser pulse. Simulations show that by sending a 1 kA, 70 MeV electron beam and 100 GW laser into a prebuncher and the reversed undulator, 41% of the electron beam energy should be converted to radiation, allowing the laser pulse power to grow to 127 GW.
TUP045 IFEL Driven Micro-Electro-Mechanical System Free Electron Laser 481
  • N.S. Sudar, J.P. Duris, P. Musumeci
    UCLA, Los Angeles, California, USA
  The Free Electron Laser has provided modern science with a tunable source of high frequency, high power, coherent radiation. To date, short wavelength FEL's have required large amounts of space in order to achieve the necessary beam energy to drive the FEL process and to reach saturation of the output radiation power. By utilizing new methods for beam acceleration as well as new undulator technology, we can decrease the space required to build these machines. In this paper, we investigate a scheme by which a tabletop XUV FEL might be realized. Utilizing the Rubicon Inverse Free Electron Laser (IFEL) at BNL together with micro-electro-mechanical system (MEMS) undulator technology being developed at UCLA, we propose a design for a compact XUV FEL.  
Tapering Enhanced Stimulated Superradiant Amplification  
  • J.P. Duris, P. Musumeci
    UCLA, Los Angeles, California, USA
  • A.Y. Murokh
    RadiaBeam, Marina del Rey, California, USA
  The electrical to optical conversion efficiency of FELs is typically limited to less than 1 percent. Efforts to improve conversion efficiency have generally involved undulator tapering to drive the interaction beyond saturation in combination with focusing the electron beam to compensate gain guiding losses within undulator. Here we propose a scheme whereby a coherent radiation seed is focused into a strongly tapered undulator to violently decelerate electrons, thereby converting as much as 70 percent of e-beam energy to coherent radiation. By tapering the undulator to accommodate the radiation growth, a modest input seed may be used to drive the FEL interaction far beyond saturation in order to achieve high electrical to optical conversion efficiency. The scheme relies on a prebunched beam and a seed laser focused into a strongly tapered undulator and is therefore called tapering enhanced stimulated superradiant amplification (TESSA).  
slides icon Slides FRB03 [1.100 MB]