Author: Dal Forno, M.
Paper Title Page
TUPEA010 FERMI Seeded FEL Progress Report 1182
 
  • M. Svandrlik, E. Allaria, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, P. Cinquegrana, P. Craievich, I. Cudin, G. D'Auria, M. Dal Forno, M.B. Danailov, R. De Monte, G. De Ninno, A.A. Demidovich, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, P. Finetti, L. Fröhlich, P. Furlan Radivo, G. Gaio, L. Giannessi, M. Kiskinova, G.L. Loda, M. Lonza, B. Mahieu, N. Mahne, C. Masciovecchio, F. Parmigiani, G. Penco, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, F. Rossi, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, S. Spampinati, C. Spezzani, L. Sturari, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • P. Craievich
    PSI, Villigen PSI, Switzerland
  • B. Mahieu
    CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France
  
  Funding: Work supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3
FERMI, the seeded Free Elec­tron Laser lo­cated at the Elet­tra lab­o­ra­tory in Tri­este, Italy, wel­comed in De­cem­ber 2012 the first ex­ter­nal users on the FEL-1 line. This line is based on a sin­gle stage of High Gain Har­monic Gen­er­a­tion (HGHG), seeded by a UV laser, and cov­ers wave­lengths be­tween 80 and 20 nm. The pho­ton en­ergy reached more than 300 μJ. The sec­ond FEL line, FEL-2, cov­er­ing the lower wave­length range be­tween 20 and 4 nm thanks to a dou­ble stage cas­caded HGHG scheme, has gen­er­ated its first co­her­ent pho­tons in Oc­to­ber 2012. This is the first ex­per­i­men­tal demon­stra­tion of a seeded free elec­tron laser con­fig­ured as a two stages cas­cade op­er­at­ing in the "fresh bunch in­jec­tion” mode, where the sec­ond stage is seeded by the light pro­duced by the first stage. This paper de­scribes the sta­tus of the op­er­a­tion and user ex­per­i­ments with FEL-1 and re­ports about the progress in the com­mis­sion­ing of FEL-2. 		 
 
WEPFI015 Design and Field Measurements of a Linear Accelerator Endowed with Single Feed with Movable Short Coupler 2732
 
  • M. Dal Forno, R. Vescovo
    University of Trieste, Trieste, Italy
  • P. Craievich, M. Dal Forno, G. Penco
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • P. Craievich
    PSI, Villigen PSI, Switzerland
  
  The free elec­tron laser per­for­mances strongly de­pend on the beam qual­ity. The dipo­lar field pre­sent in the linac cou­pler causes the beam emit­tance degra­da­tion. This paper stud­ies an al­ter­na­tive so­lu­tion for re­duc­ing the dipo­lar field, by using a sym­met­ri­cal cou­pler with sin­gle feed input and a mov­able short cir­cuit placed on the op­po­site wave­guide. The struc­ture has been sim­u­lated and op­ti­mized with the Ansys HFSS sim­u­la­tion code. An alu­minum pro­to­type has been ma­chined in the work­shop of “Elet­tra - Sin­cro­trone Tri­este S.C.p.A.”. After match­ing and tun­ing the ac­cel­er­at­ing struc­ture, the phase ad­vance and the cou­pler field asym­me­tries have been mea­sured by means of the bead-pull method and have been com­pared with the sim­u­la­tion re­sults.  
 
THPFI010 High Energy RF Deflectors for the FERMI@Elettra project 3309
 
  • M. Dal Forno, S. Biedron, D. Castronovo, P. Craievich, S. Di Mitri, D. La Civita, G. Penco, M. Petronio, F. Pradal, L. Rumiz, L. Sturari, D. Wang, D. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • P. Craievich
    PSI, Villigen PSI, Switzerland
  • M. Dal Forno, M. Petronio, R. Vescovo
    University of Trieste, Trieste, Italy
  • N. Faure
    PMB-ALCEN, PEYNIER, France
  
  Mea­sur­ing and con­trol­ling the lon­gi­tu­di­nal phase space and the time-slice emit­tance of the elec­tron bunch at 1.2 GeV en­ter­ing in the un­du­la­tor beam-lines, is cru­cial to ob­tain high FEL per­for­mances. In the FERMI@​Elettra ma­chine, two RF de­flect­ing cav­i­ties have been in­stalled at the end of the linac, in order to stretch the elec­tron bunch hor­i­zon­tally and ver­ti­cally, re­spec­tively. The two cav­i­ties are in­di­vid­u­ally pow­ered by the same kly­stron and a switch sys­tem is used to choose the de­flec­tion plane. This paper re­ports the RF mea­sure­ments car­ried out dur­ing the ac­cep­tance test, the RF con­di­tion­ing in­clud­ing the break­down rate mea­sure­ments. Fi­nally, the com­mis­sion­ing with elec­tron beam of the de­flect­ing struc­ture and a com­par­i­son of the mea­sured elec­tron bunch length eval­u­ated by using the two de­flec­tors are also re­ported.  
 
WEPFI015 Design and Field Measurements of a Linear Accelerator Endowed with Single Feed with Movable Short Coupler 2732
 
  • M. Dal Forno, R. Vescovo
    University of Trieste, Trieste, Italy
  • P. Craievich, M. Dal Forno, G. Penco
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • P. Craievich
    PSI, Villigen PSI, Switzerland
  
  The free elec­tron laser per­for­mances strongly de­pend on the beam qual­ity. The dipo­lar field pre­sent in the linac cou­pler causes the beam emit­tance degra­da­tion. This paper stud­ies an al­ter­na­tive so­lu­tion for re­duc­ing the dipo­lar field, by using a sym­met­ri­cal cou­pler with sin­gle feed input and a mov­able short cir­cuit placed on the op­po­site wave­guide. The struc­ture has been sim­u­lated and op­ti­mized with the Ansys HFSS sim­u­la­tion code. An alu­minum pro­to­type has been ma­chined in the work­shop of “Elet­tra - Sin­cro­trone Tri­este S.C.p.A.”. After match­ing and tun­ing the ac­cel­er­at­ing struc­ture, the phase ad­vance and the cou­pler field asym­me­tries have been mea­sured by means of the bead-pull method and have been com­pared with the sim­u­la­tion re­sults.  
 
THPFI010 High Energy RF Deflectors for the FERMI@Elettra project 3309
 
  • M. Dal Forno, S. Biedron, D. Castronovo, P. Craievich, S. Di Mitri, D. La Civita, G. Penco, M. Petronio, F. Pradal, L. Rumiz, L. Sturari, D. Wang, D. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • P. Craievich
    PSI, Villigen PSI, Switzerland
  • M. Dal Forno, M. Petronio, R. Vescovo
    University of Trieste, Trieste, Italy
  • N. Faure
    PMB-ALCEN, PEYNIER, France
  
  Mea­sur­ing and con­trol­ling the lon­gi­tu­di­nal phase space and the time-slice emit­tance of the elec­tron bunch at 1.2 GeV en­ter­ing in the un­du­la­tor beam-lines, is cru­cial to ob­tain high FEL per­for­mances. In the FERMI@​Elettra ma­chine, two RF de­flect­ing cav­i­ties have been in­stalled at the end of the linac, in order to stretch the elec­tron bunch hor­i­zon­tally and ver­ti­cally, re­spec­tively. The two cav­i­ties are in­di­vid­u­ally pow­ered by the same kly­stron and a switch sys­tem is used to choose the de­flec­tion plane. This paper re­ports the RF mea­sure­ments car­ried out dur­ing the ac­cep­tance test, the RF con­di­tion­ing in­clud­ing the break­down rate mea­sure­ments. Fi­nally, the com­mis­sion­ing with elec­tron beam of the de­flect­ing struc­ture and a com­par­i­son of the mea­sured elec­tron bunch length eval­u­ated by using the two de­flec­tors are also re­ported.