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.  
 
FRB03
 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]