Author: Agapov, I.V.
Paper Title Page
MOP056 SASE Characteristics from Baseline European XFEL Undulators in the Tapering Regime 159
 
  • I.V. Agapov, G. Geloni
    XFEL. EU, Hamburg, Germany
  • G. Feng, V. Kocharyan, E. Saldin, S. Serkez, I. Zagorodnov
    DESY, Hamburg, Germany
  
  The out­put SASE char­ac­ter­is­tics of the base­line Eu­ro­pean XFEL, re­cently used in the TDRs of sci­en­tific in­stru­ments and X-ray op­tics, have been pre­vi­ously op­ti­mized as­sum­ing uni­form un­du­la­tors with­out con­sid­er­ing the po­ten­tial of un­du­la­tor ta­per­ing in the SASE regime. Here we demon­strate that the per­for­mance of Eu­ro­pean XFEL sources can be sig­nif­i­cantly im­proved with­out ad­di­tional hard­ware. The pro­ce­dure con­sists in the op­ti­miza­tion of the un­du­la­tor gap con­fig­u­ra­tion for each X-ray beam­line. Here we pro­vide a com­pre­hen­sive de­scrip­tion of the X-ray pho­ton beam prop­er­ties as a func­tion of wave­length and bunch charge. Based on nom­i­nal pa­ra­me­ters for the elec­tron beam, we demon­strate that un­du­la­tor ta­per­ing al­lows one to achieve up to a ten­fold in­crease in peak power and pho­ton spec­tral den­sity in the con­ven­tional SASE regime.  
 
MOP058 Purified SASE Undulator Configuration to Enhance the Performance of the Soft X-ray Beamline at the European XFEL 169
 
  • V. Kocharyan, E. Saldin, S. Serkez, I. Zagorodnov
    DESY, Hamburg, Germany
  • I.V. Agapov, G. Geloni
    XFEL. EU, Hamburg, Germany
  
  The pu­ri­fied SASE (pSASE) un­du­la­tor con­fig­u­ra­tion re­cently pro­posed at SLAC promises an in­crease in the out­put spec­tral den­sity of XFELs. In this ar­ti­cle we study a straight­for­ward im­ple­men­ta­tion of this con­fig­u­ra­tion for the soft x-ray beam­line at the Eu­ro­pean XFEL. A few un­du­la­tor cells, res­o­nant at a sub­har­monic of the FEL ra­di­a­tion, are used in the mid­dle of the ex­po­nen­tial regime to am­plify the ra­di­a­tion, while si­mul­ta­ne­ously re­duc­ing the FEL band­width. Based on start-to-end sim­u­la­tions, we show that with the pro­posed con­fig­u­ra­tion the spec­tral den­sity in the pho­ton en­ergy range be­tween 1.3 keV and 3 keV can be en­hanced of an order of mag­ni­tude com­pared to the base­line mode of op­er­a­tion. This op­tion can be im­ple­mented into the tun­able-gap SASE3 base­line un­du­la­tor with­out ad­di­tional hard­ware, and it is com­ple­men­tary to the self-seed­ing op­tion with grat­ing mono­chro­ma­tor pro­posed for the same un­du­la­tor line, which can cover the pho­ton en­ergy range be­tween about 0.26 keV and 1 keV.  
 
TUP049 Storage Ring XFEL with Longitudinal Focusing 492
 
  • I.V. Agapov, G. Geloni
    XFEL. EU, Hamburg, Germany
  
  In pre­sent work we in­ves­ti­gate the pos­si­bil­ity of run­ning a high gain FEL on a stor­age ring using a lon­gi­tu­di­nally fo­cus­ing in­ser­tion to com­press bunches pass­ing an un­du­la­tor. If in­te­grated into a stor­age ring sim­i­lar to PETRA III such de­vice could po­ten­tially pro­duce con­tin­u­ous ∼1ps pulses of pho­tons in the nm range with peak pulse pow­ers of tens of GW. Even with­out op­er­at­ing in FEL sat­u­ra­tion mode the lon­gi­tu­di­nal fo­cus­ing can pro­vide means to in­crease the bright­ness and shorten the pho­ton pulse length