Author: Schreiber, S.
Paper Title Page
MOA03 First Lasing at FLASH2 7
  • S. Schreiber, B. Faatz
    DESY, Hamburg, Germany
  FLASH, the free-electron laser user facility at DESY (Hamburg, Germany), has been upgraded with a second undulator beamline FLASH2. The installation of the FLASH2 electron beamline, including twelve variable gap undulators, was finalized early 2014, and beam commissioning of the new beamline started in March 2014. We announce first lasing at FLASH2 achieved at a wavelength of 40 nm on August 20, 2014.  
slides icon Slides MOA03 [3.896 MB]  
MOP059 Beam Dynamic Simulations for Single Spike Radiation with Short-Pulse Injector Laser at FLASH 173
  • M. Rehders
    University of Hamburg, Hamburg, Germany
  • J. Rönsch-Schulenburg
    CFEL, Hamburg, Germany
  • J. Rönsch-Schulenburg, J. Roßbach
    Uni HH, Hamburg, Germany
  • S. Schreiber
    DESY, Hamburg, Germany
  Funding: The project has been supported by the Federal Ministry of Education and Research of Germany (BMBF) under contract No. 05K10GU2 and FSP301
This paper discusses the generation of single spike SASE pulses at soft x-ray wavelength at the free-electron laser FLASH by using very short electron bunches of only a few micrometer bunch length. In order to achieve these extremely short bunch lengths, very low bunch charges (in the order of 20 pC) and short electron bunches exiting the photo-injector are required. For this, a new short-pulse injector laser with adjustable rms pulse duration in the range of 0.7 ps to 1.6 ps and bunch charges up to 200 pC was installed, extending the electron beam parameter range before bunch compression in magnetic chicanes. Beam dynamic studies have been performed to optimize the injection and compression of low-charge electron bunches by controlling the effect of coherent synchrotron radiation and space-charge induced bunch lengthening and emittance growth. Optimization includes the pulse parameters of the injector laser. The simulation codes ASTRA, CSRtrack and Genesis 1.3 were employed.
TUB04 Operation of FLASH with Short SASE-FEL Radiation Pulses 342
  • J. Rönsch-Schulenburg, E. Hass, N.M. Lockmann, T. Plath, M. Rehders, J. Roßbach
    Uni HH, Hamburg, Germany
  • G. Brenner, S. Dziarzhytski, T. Golz, H. Schlarb, B. Schmidt, E. Schneidmiller, S. Schreiber, B. Steffen, N. Stojanovic, S. Wunderlich, M.V. Yurkov
    DESY, Hamburg, Germany
  Funding: The project has been supported by the Federal Ministry of Education and Research of Germany (BMBF) under contract No. 05K10GU2 and FSP301
This paper describes the experimental activity on the generation of very short FEL pulses in the soft x-ray range in the SASE-mode at the high-gain free-electron laser FLASH [1, 2]. The key element, a photo-injector laser which is able to generate laser pulses of about 2 ps FWHM has been optimized and commissioned. It allows the generation of shorter bunches with low bunch charge (of up to 200 pC) directly at the photo-cathode. Initially shorter injector laser pulses and thus shorter bunches eases the required bunch compression factor for short pulses below 10 fs duration which makes operation of the electron beam formation system to be more robust with respect to jitters and collective effects. As a result, overall stability of SASE FEL performance is improved. In the optimal case single-spike operation can be achieved. In this paper the experimental results on production of short electron bunches and the SASE performance using the new injector laser will be shown and the measured electron bunch and FEL radiation properties are discussed. In addition, optimizations of bunch diagnostics for low charge and short bunches are discussed.
slides icon Slides TUB04 [1.201 MB]  
WEB05 FLASH: First Soft X-ray FEL Operating Two Undulator Beamlines Simultaneously 635
  • K. Honkavaara, B. Faatz, J. Feldhaus, S. Schreiber, R. Treusch, M. Vogt
    DESY, Hamburg, Germany
  FLASH, the free electron laser user facility at DESY (Hamburg, Germany), has been upgraded with a second undulator beamline FLASH2. After a shutdown to connect FLASH2 to the FLASH linac, FLASH1 is back in user operation since February 2014. Installation of the FLASH2 electron beamline has been completed early 2014, and the first electron beam was transported into the new beamline in March 2014. The commissioning of FLASH2 takes place in 2014 parallel to FLASH1 user operation. This paper reports the status of the FLASH facility, and the first experience of operating two FEL beamlines.  
slides icon Slides WEB05 [2.481 MB]  
THP060 Design of a Spatio-temporal 3-D Ellipsoidal Photo Cathode Laser System for the High Brightness Photo Injector PITZ 878
  • T. Rublack, J.D. Good, M. Khojoyan, M. Krasilnikov, F. Stephan
    DESY Zeuthen, Zeuthen, Germany
  • A.V. Andrianov, E. Gacheva, E. Khazanov, S. Mironov, A. Poteomkin, V. Zelenogorsky
    IAP/RAS, Nizhny Novgorod, Russia
  • I. Hartl, S. Schreiber
    DESY, Hamburg, Germany
  • E. Syresin
    JINR, Dubna, Moscow Region, Russia
  Funding: German Federal Ministry of education and Research, project 05K10CHE “Development and experimental test of a laser system for producing quasi 3D ellipsoidal laser pulses” and RFBR grant 13-02-91323.
Minimized emittance is crucial for improved operation of linac-based free electron lasers. Simulations have thus shown 3-D ellipsoidal photocathode laser pulses are superior to the standard Gaussian or cylindrical laser pulses in this manner. Therefore, in collaboration with the Joint Institute of Nuclear Research (JINR, Dubna, Russia) and the Photo Injector Test facility at DESY, Zeuthen (PITZ), a prototype system capable of producing spatio-temporal 3-D ellipsoidal pulses has been constructed at the Institute of Applied Physics (IAP, Nizhny Novgorod, Russia). The system consists of a dual-output, 1030 nm fiber laser coupled with disc amplifiers, a scheme based on Spatial Light Modulators for spatial and temporal pulse shaping of the primary output, a cross-correlator set up utilizing the secondary output to characterize the primary output, and finally frequency conversion to the UV. A preliminary, temporal ellipsoidal shaped IR pulse has been observed and measured so far at IAP RAS. As of writing, improvements and refinements of the system are ongoing and it is expected to replicate the finalized prototype at PITZ soon.
THP076 Measurements of the Timing Stability at the FLASH1 Seeding Experiment 913
  • C. Lechner, A. Azima, M. Drescher, L.L. Lazzarino, Th. Maltezopoulos, V. Miltchev, T. Plath, J. Rönsch-Schulenburg, J. Roßbach, M. Wieland
    Uni HH, Hamburg, Germany
  • S. Ackermann, J. Bödewadt, H. Dachraoui, N. Ekanayake, B. Faatz, M. Felber, K. Honkavaara, T. Laarmann, J.M. Mueller, H. Schlarb, S. Schreiber, S. Schulz
    DESY, Hamburg, Germany
  • G. Angelova Hamberg
    Uppsala University, Uppsala, Sweden
  • K.E. Hacker, S. Khan, R. Molo
    DELTA, Dortmund, Germany
  • P.M. Salen, P. van der Meulen
    FYSIKUM, AlbaNova, Stockholm University, Stockholm, Sweden
  Funding: Supported by Federal Ministry of Education and Research of Germany under contract No. 05K10PE1, 05K10PE3, 05K13GU4 and 05K13PE3 and the German Research Foundation programme graduate school 1355.
For seeding of a free-electron laser, the spatial and temporal overlap of the seed laser pulse and the electron bunch in the modulator is critical. To establish the temporal overlap, the time difference between pulses from the seed laser and spontaneous undulator radiation is reduced to a few pico-seconds with a combination of a photomultiplier tube and a streak camera. Finally, for the precise overlap the impact of the seed laser pulses on the electron bunches is observed. In this contribution, we describe the current experimental setup, discuss the techniques applied to establish the temporal overlap and analyze its stability.