Author: Loehl, F.    [Löhl, F.]
Paper Title Page
WEP037 RF Jitter and Electron Beam Stability in the SwissFEL Linac 400
 
  • Z.G. Geng, J. Alex, V.R. Arsov, P. Craievich, C.H. Gough, R. Kalt, T. Lippuner, F. Löhl, M. Pedrozzi, E. Prat, S. Reiche
    PSI, Villigen PSI, Switzerland
  
  The X-ray FEL machine SwissFEL at the Paul Scherrer Institut in Switzerland is commissioned and transiting to user operation smoothly. FEL operation requires stringent requirements for the beam stability at the linac output, such as the electron bunch arrival time, peak current and energy. Among other things, a highly stable RF system is required to guarantee the beam stability. The SwissFEL RF system is designed based on the state-of-the-art technologies that have allowed achieving excellent RF stability. The propagation of RF amplitude and phase jitter to the electron beam are analyzed theoretically and compared with the measurements performed at SwissFEL.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WEP037  
About • paper received ※ 20 August 2019       paper accepted ※ 27 August 2019       issue date ※ 05 November 2019  
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WED01 Experience with Short-Period, Small Gap Undulators at the SwissFEL Aramis Beamline 564
 
  • T. Schmidt, M. Aiba, A.D. Alarcon, C. Arrell, S. Bettoni, M. Calvi, A. Cassar, E. Ferrari, R. Follath, R. Ganter, N. Hiller, P.N. Juranič, C. Kittel, F. Löhl, E. Prat, S. Reiche, T. Schietinger, D. Voulot, U.H. Wagner
    PSI, Villigen PSI, Switzerland
  • N.J. Sammut
    University of Malta, Faculty of Engineering, Msida, Malta
  
  The SwissFEL Aramis beamline provides hard X-ray FEL radiation down to 1 Angström with 5.8 GeV and short period, 15 mm, in-vacuum undulators (U15). To reach the maximum designed K-value of 1.8 the U15s have to be operated with vacuum gaps down to 3.0 mm. The thirteen-undulator modules are 4 m long and each of them is equipped with a pair of permanent magnet quadrupoles at the two ends, aligned magnetically to the undulator axis. Optical systems and dedicated photon diagnostics are used to check the alignment and improve the K-value calibration. In this talk the main steps of the undulator commissioning will be recalled and a systematic comparison between the magnetic results and the electron and photon based measurements will be reported to highlight achievements and open issues.  
slides icon Slides WED01 [13.825 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WED01  
About • paper received ※ 28 August 2019       paper accepted ※ 06 November 2019       issue date ※ 05 November 2019  
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THB03
 Emittance Measurements and Minimization at SwissFEL  
 
  • E. Prat, M. Aiba, S. Bettoni, P. Craievich, P. Dijkstal, E. Ferrari, R. Ischebeck, F. Löhl, A. Malyzhenkov, G.L. Orlandi, S. Reiche, T. Schietinger
    PSI, Villigen PSI, Switzerland
  
  The transverse emittance of the electron beam is a fundamental parameter that determines the performance of free-electron-lasers (FELs). In this contribution, we present emittance measurements carried out at SwissFEL, the X-ray FEL facility that recently started to operate at PSI in Switzerland, including a description of our measurement methods and optimization procedures. We obtained slice emittance values at the undulator entrance down to ~200 nm for an electron beam with a charge of 200 pC and an r.m.s. duration of ~30 fs. Furthermore, we achieved slice emittances as low as ~100 nm for 10 pC beams with few femtosecond duration.  
slides icon Slides THB03 [6.285 MB]  
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THP085 Status of Athos, the Soft X-Ray FEL Line of SwissFEL 753
 
  • R. Ganter, G. Aeppli, A. Al Haddad, J. Alex, C. Arrell, V.R. Arsov, S. Bettoni, C. Bostedt, H.-H. Braun, M. Calvi, T. Celcer, P. Craievich, R. Follath, F. Frei, N. Gaiffi, Z.G. Geng, C.H. Gough, M. Huppert, R. Ischebeck, H. Jöhri, P.N. Juranič, B. Keil, F. Löhl, F. Marcellini, G. Marinkovic, G.L. Orlandi, C. Ozkan Loch, M. Paraliev, L. Patthey, M. Pedrozzi, C. Pradervand, E. Prat, S. Reiche, T. Schietinger, T. Schmidt, K. Schnorr, C. Svetina, A. Trisorio, C. Vicario, D. Voulot, U.H. Wagner, A.C. Zandonella
    PSI, Villigen PSI, Switzerland
  
  The Athos line will cover the photon energy range from 250 to 1900 eV and will operate in parallel to the hard X-ray line Aramis of SwissFEL. The paper will describe the current layout of the Athos FEL line starting from the fast kicker magnet followed by the dogleg transfer line, the small linac and the 16 APPLE undulators. From there the photon beam passes through the photonics front end and the beamline optics before reaching the experimental stations AMO and FURKA. The focus of this contribution will be on the two bunch operation commissioning (two bunches in the same RF macropulse), which started in 2018, and the characterization of the major components like the APPLE X undulator UE38, the CHIC chicane and the dechirper. The Athos installation inside the tunnel is alternating with Aramis FEL user operation and the first lasing is planned for winter 2019 / 2020.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THP085  
About • paper received ※ 30 July 2019       paper accepted ※ 28 August 2019       issue date ※ 05 November 2019  
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