Author: Pannek, F.
Paper Title Page
TUPAB103 Discussion on CSR instability in EEHG Simulation 1622
 
  • D. Samoilenko, W. Hillert
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • F. Curbis, M.A. Pop, S. Werin
    MAX IV Laboratory, Lund University, Lund, Sweden
  • P. Niknejadi, G. Paraskaki
    DESY, Hamburg, Germany
  • F. Pannek
    University of Hamburg, Hamburg, Germany
  
  Echo-En­abled Har­monic Gen­er­a­tion (EEHG) is an ex­ter­nal seed­ing tech­nique for XUV and soft X-ray Free Elec­tron Lasers (FEL). It has re­cently been ex­per­i­men­tally demon­strated and cur­rently many fa­cil­i­ties world­wide in­tend to in­cor­po­rate it in user op­er­a­tion. The EEHG process re­lies on very ac­cu­rate and com­plex trans­for­ma­tions of elec­tron beam phase space by means of a se­ries of un­du­la­tors cou­pled to lasers and dis­per­sive chi­canes. As a re­sult of the phase space ma­nip­u­la­tion, elec­trons are bunched at a high har­monic of the seed laser wave­length al­low­ing co­her­ent emis­sion at few nm wave­length. Dis­per­sion oc­cur­ring in strong chi­canes is im­per­a­tive for im­ple­men­ta­tion of this scheme and ef­fec­tive elec­tron bunch­ing gen­er­a­tion. How­ever, strong chi­canes at the same time can be source of beam in­sta­bil­ity ef­fects, such as Co­her­ent Syn­chro­tron Ra­di­a­tion (CSR), that can sig­nif­i­cantly grow in these con­di­tions and sup­press the bunch­ing process. There­fore, there is a com­mon need to in­ves­ti­gate such ef­fects in de­tail. Here, we dis­cuss their treat­ment with sim­u­la­tion codes ap­plied to a typ­i­cal EEHG setup.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB103  
About • paper received ※ 19 May 2021       paper accepted ※ 17 June 2021       issue date ※ 12 August 2021  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
FRXA06 Mitigation of Beam Instabilities in the Echo-Enabled Harmonic Generation Beamline for FLASH2020+ 4514
 
  • F. Pannek, W. Hillert, D. Samoilenko
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • S. Ackermann, E. Allaria, P. Niknejadi, G. Paraskaki, L. Schaper
    DESY, Hamburg, Germany
  • M.A. Pop
    MAX IV Laboratory, Lund University, Lund, Sweden
  
  With the FLASH2020+ up­grade, one of the beam­lines of the free-elec­tron laser FLASH at DESY will be based on the Echo-En­abled Har­monic Gen­er­a­tion (EEHG) seed­ing scheme and pro­vide high-rep­e­ti­tion-rate, co­her­ent ra­di­a­tion down to 4 nm. To reach this wave­length, it is nec­es­sary to im­print in­tri­cate struc­tures on the lon­gi­tu­di­nal phase space of the elec­tron bunch at a very high har­monic of the seed laser wave­length, mak­ing the scheme po­ten­tially vul­ner­a­ble to beam in­sta­bil­i­ties. Part of the beam­line is a strong chi­cane, which is nec­es­sary to cre­ate the dis­per­sion re­quired by EEHG. Re­sult­ing ef­fects such as Co­her­ent Syn­chro­tron Ra­di­a­tion (CSR) can be very detri­men­tal for the bunch­ing process and have to be taken into ac­count al­ready in the de­sign of the beam­line to en­sure op­ti­mum FEL per­for­mance. We in­ves­ti­gate and pro­pose pos­si­ble mit­i­ga­tion so­lu­tions to such in­sta­bil­i­ties in the FLASH2020+ pa­ra­me­ter range.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXA06  
About • paper received ※ 19 May 2021       paper accepted ※ 20 July 2021       issue date ※ 20 August 2021  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)