Author: Michel, P.
Paper Title Page
MOOBNO02
 FEL Operation With the Superconducting RF Photo Gun at ELBE  
 
  • J. Teichert, A. Arnold, H. Büttig, M. Justus, U. Lehnert, P.N. Lu, P. Michel, P. Murcek, R. Schurig, W. Seidel, H. Vennekate, R. Xiang
    HZDR, Dresden, Germany
  • T. Kamps, J. Rudolph
    HZB, Berlin, Germany
  • I. Will
    MBI, Berlin, Germany
  
  The superconducting RF photoinjector (SRF gun) operating with a 31/2-cell niobium cavity and Cs2Te photocathodes is installed at the ELBE radiation center. The gun provides beams for ELBE as well as in a separate diagnostics beam line for beam parameter measurements. Since 2012 a new UV driver laser system developed by MBI has been installed for the SRF gun . It delivers CW or bust mode pulses with 13 MHz repetition rate or with reduced rates of 500, 200, and 100 kHz at an average UV power of about 1 W. The new laser allows the gun to serve as the driver for the infrared FELs at ELBE. In the first successful experiment a 250 μA beam with 3.3 MeV from SRF gun was injected into ELBE, further accelerated in the ELBE superconducting linac modules and then guided to the U100 undulator. First lasing was achieved at the wavelength of 41 μm. The spectrum, detuning curve and further parameters were measured.  
slides icon Slides MOOBNO02 [7.458 MB]  
 
MOPSO76 FEL Operation With the Superconducting RF Photo Gun at ELBE 136
 
  • J. Teichert, A. Arnold, H. Büttig, M. Justus, U. Lehnert, P.N. Lu, P. Michel, P. Murcek, R. Schurig, W. Seidel, H. Vennekate, R. Xiang
    HZDR, Dresden, Germany
  • T. Kamps, J. Rudolph
    HZB, Berlin, Germany
  • I. Will
    MBI, Berlin, Germany
  
  The superconducting RF photoinjector (SRF gun) operating with a 31/2-cell niobium cavity and Cs2Te photocathodes is installed at the ELBE radiation center. The gun provides beams for ELBE as well as in a separate diagnostics beam line for beam parameter measurements. Since 2012 a new UV driver laser system developed by MBI has been installed for the SRF gun . It delivers CW or bust mode pulses with 13 MHz repetition rate or with reduced rates of 500, 200, and 100 kHz at an average UV power of about 1 W. The new laser allows the gun to serve as the driver for the infrared FELs at ELBE. In the first successful experiment a 250 μA beam with 3.3 MeV from SRF gun was injected into ELBE, further accelerated in the ELBE superconducting linac modules and then guided to the U100 undulator. First lasing was achieved at the wavelength of 41 μm. The spectrum, detuning curve and further parameters were measured.  
 
TUPSO44 Transverse Emittance Measurement by Slit-scan Method for an SRF Photo Injector 322
 
  • P.N. Lu, A. Arnold, P. Michel, P. Murcek, J. Teichert, H. Vennekate, R. Xiang
    HZDR, Dresden, Germany
  
  Funding: European Community-Research Infrastructure Activity German Federal Ministry of Education and Research Grant 05 ES4BR1/8, LA³NET funding, Grant Agreement Number GA-ITN-2011-289191
A 3½-cell SRF-gun has been developed and commissioned in Helmholtz-Zentrum Dresden-Rossendorf (HZDR) since 2004. The emittance of this gun was measured before by both solenoid/quadrupole scanning method and multiple slits method. Recently we did new measurements by single slit scanning method which outputs a detailed phase space with higher space resolution and no overlapping problem. This contribution will first describe our diagnostics beam line and software functions, focusing on data processing algorithm. Then an investigation will be presented on the emittance dependence on several important gun parameters as bunch charge, laser phase and DC voltage on the photo cathode. For the bunch charge, a linear increasing relation with the emittance was found. Lower laser phase and higher DC voltage result in lower beam emittance. The influence of a downstream solenoid is studied for the preliminary understanding of the emittance compensation. The contribution will discuss the measurement errors and compare results with other methods. Also, ASTRA simulations of the SRF-gun beams with same parameters will be presented which have similar trends like our measurements. 		 
 
WEPSO62 The IR and THz Free Electron Laser at the Fritz-Haber-Institut 657
 
  • W. Schöllkopf, W. Erlebach, S. Gewinner, G. Heyne, H. Junkes, A. Liedke, G. Meijer, V. Platschkowski, G. von Helden
    FHI, Berlin, Germany
  • H. Bluem, D. Dowell, K. Jordan, R. Lange, J. Rathke, A.M.M. Todd, L.M. Young
    AES, Medford, NY, USA
  • M.A. Davidsaver
    BNL, Upton, New York, USA
  • S.C. Gottschalk
    STI, Washington, USA
  • U. Lehnert, P. Michel, W. Seidel, R. Wünsch
    HZDR, Dresden, Germany
  • H. Loos
    SLAC, Menlo Park, California, USA
  
  A mid-infrared oscillator FEL with a design wavelength range from 4 to 50 μm has been commissioned at the Fritz-Haber-Institut in Berlin, Germany, for applications in molecular and cluster spectroscopy as well as surface science. The accelerator consists of a thermionic gridded electron gun, a subharmonic buncher and two S-band standing-wave copper structures. The device was designed to meet challenging specifications, including a final energy adjustable in the range of 15 to 50 MeV, low longitudinal emittance (< 50 keV-psec) and transverse emittance (< 20 π mm-mrad), at more than 200 pC bunch charge with aμpulse repetition rate of 1 GHz and a macro pulse length of up to 15 μs. Two isochronous achromatic 180 degree bends deliver the beam to the undulators, only one of which is presently installed, and to the beam dumps. Calculations of the FEL gain and IR-cavity losses predict that lasing will be possible in the wavelength range from less than 4 to more than 50 μm. First lasing was achieved at a wavelength of 16 μm in 2012*. We will describe the FEL system design and performance, provide examples of lasing, and touch on the first anticipated user experiments.
* W. Schöllkopf et al., MOOB01, Proc. FEL 2012.