Author: Schultheiss, T.
Paper Title Page
TUPB30 Status of the Fritz Haber Institute THz FEL 315
 
  • W. Schöllkopf, W. Erlebach, S. Gewinner, H. Junkes, A. Liedke, G. Meijer, W.Q. Zhang, G. von Helden
    FHI, Berlin, Germany
  • H. Bluem, V. Christina, M.D. Cole, J. Ditta, D. Dowell, R. Lange, J.H. Park, J. Rathke, T. Schultheiss, A.M.M. Todd, L.M. Young
    AES, Medford, NY, USA
  • S.C. Gottschalk
    STI, Washington, USA
  • K. Jordan
    Kevin Jordan PE, Newport News, Virginia, USA
  • U. Lehnert, P. Michel, W. Seidel, R. Wünsch
    FZD, Dresden, Germany
 
  The THz FEL at the Fritz Haber In­sti­tute (FHI) in Berlin is de­signed to de­liver ra­di­a­tion from 4 to 400 mi­crons. A sin­gle-plane-fo­cus­ing un­du­la­tor com­bined with a 5.4 m long cav­ity is used is the mid-IR (< 50 mi­cron), while a two-plane-fo­cus­ing un­du­la­tor in com­bi­na­tion with a 7.2 m long cav­ity with a 1-d wave­guide for the op­ti­cal mode is used for the far-IR. A key as­pect of the ac­cel­er­a­tor per­for­mance is low lon­gi­tu­di­nal emit­tance, < 50 keV-psec, at 200 pC bunch charge and 50 MeV from a grid­ded thermionic elec­tron source. We uti­lize twin ac­cel­er­at­ing struc­tures sep­a­rated by a chi­cane to de­liver the re­quired per­for­mance over the < 20 - 50 MeV en­ergy range. The first struc­ture op­er­ates at near fixed field while the sec­ond struc­ture con­trols the out­put en­ergy, which, under some con­di­tions, re­quires run­ning in a de­cel­er­at­ing mode. "First Light" is tar­geted for the cen­ten­nial of the FHI in Oc­to­ber 2011 and we will de­scribe progress in the com­mis­sion­ing of this de­vice. Specif­i­cally, the mea­sured per­for­mance of the ac­cel­er­ated elec­tron beam will be com­pared to de­sign sim­u­la­tions and the ob­served match­ing of the beam to the mid-IR wig­gler will be de­scribed.