Author: Dohlus, M.
Paper Title Page
TUP056 Feasibility Studies of the 100 keV Undulator Line of the European XFEL 172
 
  • E. Schneidmiller, V. Balandin, W. Decking, M. Dohlus, N. Golubeva, D. Nölle, M.V. Yurkov, I. Zagorodnov
    DESY, Hamburg, Germany
  • G. Geloni, Y. Li, S. Molodtsov, J. Pflüger, S. Serkez, H. Sinn, T. Tanikawa, S. Tomin
    EuXFEL, Hamburg, Germany
 
  The European XFEL is a multi-user X-ray FEL facility based on superconducting linear accelerator. Presently, three undulators (SASE1, SASE2, SASE3) deliver high-brightness soft- and hard- X-ray beams for users. There are two empty undulator tunnels that were originally designed to operate with spontaneous radiators. We consider instead a possible installation of two FEL undulators. One of them (SASE4) is proposed for the operation in ultrahard X-ray regime, up to the photon energy of 100 keV. In this contribution we present the results of the first feasibility studies of this option.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP056  
About • paper received ※ 20 August 2019       paper accepted ※ 27 August 2019       issue date ※ 05 November 2019  
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TUP058 First Characterization of the Photon Beam at the European XFEL in July, 2017 180
 
  • V. Balandin, B. Beutner, F. Brinker, W. Decking, M. Dohlus, L. Fröhlich, U. Jastrow, R. Kammering, T. Limberg, D. Nölle, M. Scholz, A.A. Sorokin, K.I. Tiedtke, M.V. Yurkov, I. Zagorodnov
    DESY, Hamburg, Germany
  • U. Boesenberg, W. Freund, J. Grünert, A. Koch, N.G. Kujala, J. Liu, Th. Maltezopoulos, M. Messerschmidt, I. Petrov, L. Samoylova, H. Sinn
    EuXFEL, Schenefeld, Germany
 
  North branch of the European XFEL, SASE1, produced first light on May 3rd, 2017, and XFEL operation has been gradually improved then. First characterization of the photon beam has been performed in July / August 2017, just before an official starting date of user experiments (September 1st, 2017). Energy of the electron beam was 14 GeV, bunch charge was 500 pC, photon energy was 9.3 keV. With photon diagnostics available at that time (X-ray gas monitor (XGM) and FEL imager) we measured the gain curve and traced evolution of the FEL radiation mode along the undulator. An important conclusion is that experimental results demonstrate reasonable agreement with baseline parameters. Developed techniques of the photon beam characterization also provided solid base for identification of the problems and means for improving SASE FEL tuning and operation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP058  
About • paper received ※ 20 August 2019       paper accepted ※ 27 August 2019       issue date ※ 05 November 2019  
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TUP060 An Advanced Compression Option for the European XFEL 187
 
  • I. Zagorodnov, M. Dohlus, E. Schneidmiller, M.V. Yurkov
    DESY, Hamburg, Germany
 
  An advanced compression scheme which allows to obtain a high peak current while preserving the low slice emittance is considered. The beam is compressed weakly in the bunch compressors and the current is increased by eSASE setup at the entrance of the undulator line. It is shown by numerical studies that such approach allows to reduce harmful collective effects in the bunch compressors and in the transport line. Simulations of FEL physics confirm the possibility to obtain a high level of SASE radiation at the ultra-hard photon energy level of 100 keV.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP060  
About • paper received ※ 19 August 2019       paper accepted ※ 25 August 2019       issue date ※ 05 November 2019  
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TUP061 Super-X: Simulations for Extremely Hard X-Ray Generation With Short Period Superconducting Undulators for the European XFEL 191
 
  • S. Serkez, G. Geloni, S. Karabekyan, Y. Li, T. Tanikawa, S. Tomin, F. Wolff-Fabris
    EuXFEL, Hamburg, Germany
  • C. Boffo
    Bilfinger Noell GmbH, Wuerzburg, Germany
  • S. Casalbuoni
    KIT, Eggenstein-Leopoldshafen, Germany
  • M. Dohlus, E. Schneidmiller, M.V. Yurkov, I. Zagorodnov
    DESY, Hamburg, Germany
  • A. Trebushinin
    BINP, Novosibirsk, Russia
 
  The European XFEL is a high-repetition multi-user facility with nominal photon energy range covering almost 3 orders of magnitude: 250 eV - 25 keV. In this work we explore the possibility to extend the photon energy range of the facility up to 100 keV via combination of superconducting undulator technology, period doubling and harmonic lasing, thus allowing for excellent tunability. To this purpose, we propose a dedicated FEL line, discuss its overall concept and provide analytical and numerical estimations of its expected performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP061  
About • paper received ※ 20 August 2019       paper accepted ※ 25 August 2019       issue date ※ 05 November 2019  
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WEP051 PITZ Experimental Optimization for the Aimed Cathode Gradient of a Superconducting CW RF Gun 440
 
  • M. Krasilnikov, P. Boonpornprasert, Y. Chen, G.Z. Georgiev, J.D. Good, M. Groß, P.W. Huang, I.I. Isaev, C. Koschitzki, S. Lal, X. Li, O. Lishilin, G. Loisch, D. Melkumyan, R. Niemczyk, A. Oppelt, H.J. Qian, H. Shaker, G. Shu, F. Stephan, G. Vashchenko
    DESY Zeuthen, Zeuthen, Germany
  • M. Dohlus, E. Vogel
    DESY, Hamburg, Germany
 
  A continuous wave (CW) mode operation of the European X-ray Free-Electron Laser (XFEL) is under considerations for a future upgrade. Therefore, a superconducting radio frequency (SRF) CW gun is under experimental development at DESY in Hamburg. Beam dynamics simulations for this setup have been done assuming 100 pC bunch charge and a maximum electric field at the photocathode of 40 MV/m. Experimental studies for these parameters using a normal conducting RF photogun have been performed at the Photo Injector Test facility at DESY in Zeuthen (PITZ). The beam transverse emittance was minimized by optimizing the main photo injector parameters in order to demonstrate the feasibility of generating electron beams with a beam quality required for successful CW operation of the European XFEL for conditions similar to the SRF gun setup.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-WEP051  
About • paper received ※ 20 August 2019       paper accepted ※ 27 August 2019       issue date ※ 05 November 2019  
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THP009 Space Charge Field Beam Dynamics Simulations for the THz SASE FEL at PITZ 606
 
  • S.A. Schmid, H. De Gersem, E. Gjonaj
    TEMF, TU Darmstadt, Darmstadt, Germany
  • M. Dohlus
    DESY, Hamburg, Germany
  • M. Krasilnikov
    DESY Zeuthen, Zeuthen, Germany
 
  Funding: This work is supported by the DFG in the framework of GRK 2128.
A proof-of-principle experiment on a THz SASE FEL is under consideration at the Photo Injector Test facility at DESY in Zeuthen (PITZ). One of its options assumes utilization of 4.0 nC bunches at 16.7 MeV [1]. In this operation mode, space charge interaction strongly influences the dynamics of the electron beam inside the undulator. In this contribution, we investigate the beam dynamics in the THz undulator of PITZ using a particle-particle interaction model based on a Lienard-Wiechert approach. We analyze the influence of retardation and radiation fields on the beam dynamics resulting in the microbunching effect. Furthermore, we compute the radiation field and estimate the radiation power at the exit of the undulator. The validity of the underlying numerical models is discussed.
[1] M. Krasilnikov et al., in Proc. ICAP’18, Key West, USA, paper TUPAF23, 2018
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THP009  
About • paper received ※ 20 August 2019       paper accepted ※ 27 August 2019       issue date ※ 05 November 2019  
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THP049 A Versatile THz Source for High-Repetition Rate XFELs 688
 
  • F. Lemery, M. Dohlus, K. Flöttmann, M. Marx
    DESY, Hamburg, Germany
  • M. Ivanyan, V.M. Tsakanov
    CANDLE, Yerevan, Armenia
 
  Funding: FL was partially funded by the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No. 730871
The development of high-repetition rate XFELs brings an exciting time for novel fundamental science exploration via pump-probe interactions. Laser-based pump sources can provide a wide range of wavelengths (200-10000~nm) via various gain media. These sources can also be extended with optical parametric amplifiers to cover a largely versatile spectral and bandwidth range. However beyond 10~μm, toward the THz regime, there exists no suitable gain media, and optical-to-THz efficiencies are limited below 1\%. In this paper we discuss the use of Cherenkov-based radiators with conventional electron bunches to generate high-power THz radiation over a wide range of parameters for existing and future XFEL facilities.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THP049  
About • paper received ※ 25 August 2019       paper accepted ※ 28 August 2019       issue date ※ 05 November 2019  
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