Keyword: space-charge
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MOPSO81 Broad-band Amplifier Based on Two-stream Instability electron, FEL, plasma, free-electron-laser 144
 
  • G. Wang, Y.C. Jing, V. Litvinenko
    BNL, Upton, Long Island, New York, USA
 
  A broadband FEL amplifier is of great interests for short-pulse generation in FEL technology as well as for novel hadron beam cooling technique, such as CeC. We present our founding of a broadband amplification in 1D FEL based on electron beam with two energy peaks and a strong space charge forces. We present the optimization of such amplifier and connect its origin to the two-stream instability in electron plasma. In this work, we study how the two-stream instability affects the FEL process and consider various applications in amplifying short spikes of electron current modulation.  
 
TUPSO07 SwissFEL Injector Design: An Automatic Procedure emittance, gun, laser, simulation 219
 
  • S. Bettoni, M. Pedrozzi, S. Reiche
    PSI, Villigen PSI, Switzerland
 
  The first section of photo-injectors are dominated by space charge effects due to the low beam energy and the high charge density. An optimization of several parameters such as the emittance and the mismatch along the bunch has to be carried out in order to optimize the final performances of the machine. We focus on the performances of the gun developed at PSI, planned to be installed in the mid of this year in the SwissFEL Injector Test Facility (SITF). Due to the number of variables and constraints we developed a code to automatically perform such an optimization. We used this code to optimize the 200 pC operating point of SwissFEL and to fine tune other charges configurations from 10 pC, obtaining considerably reduction of the slice emittance as compared to the CTF gun, presently installed in the SITF and on which the old lattice optimization was based. The same code with minor modifications has been successfully applied to the facility.  
 
TUPSO18 Optimization of Dielectric Loaded Metal Waveguides for Acceleration of Electron Bunches using Short THz Pulses electron, acceleration, laser, emittance 250
 
  • A. Fallahi, F.X. Kaertner
    CFEL, Hamburg, Germany
  • F.X. Kaertner, A. Sell, L.J. Wong
    MIT, Cambridge, Massachusetts, USA
 
  Funding: DARPA contract number N66001-11-1-4192 and the Center for Free-Electron Laser Science, DESY Hamburg
The last decade has witnessed extensive research efforts to reduce the size of charged particle accelerators to achieve compact devices for providing relativistic particles. To this end, various methods such as laser plasma and dielectric wakefield acceleration are investigated and their pros and cons are studied. With the advent of efficient THz generation techniques based on optical rectification, THz waveguides are also considered to be proper candidates for compact accelerators. Sofar, the proposed schemes toward high power THz generation are capable of producing short pulses, which dictates the study of particle acceleration in the pulsed regime rather than continuous-wave regime. Therefore, THz waveguides are more suitable than cavities for the considered purpose*. Consequently, various effects such as group velocity mismatch and group velocity dispersion start to influence the acceleration scenario and impose limits on the maximum energy gain from the pulse. In this contribution, we investigate electron bunch acceleration and compression in dielectrically loaded metal waveguides for the THz wavelength range and present design methodologies to optimize their performance.
* Liang Jie Wong, Arya Fallahi, and Franz X. Kärtner. "Compact electron acceleration and bunch compression in THz waveguides." Optics Express 21, no. 8 (2013): 9792-9806.
 
 
TUPSO85 High Brightness Electron Beams from a Multi-filamentary Niobium-tin Photocathode electron, cathode, emittance, laser 431
 
  • C. Vicario, A. Anghel, F. Ardana-Lamas, C.P. Hauri, F. Le Pimpec
    PSI, Villigen PSI, Switzerland
  • C.P. Hauri
    EPFL, Lausanne, Switzerland
 
  High-brightness electron sources are of fundamental interest for modern FELs. Inspired by the micro-structure of field emitter arrays, we propose a new type of metallic photo-cathode consisting of thousands of Nb3Sn micro-columns. With this metallic photo-cathode quantum efficiencies up to 0.5% are achieved under stable operation, and preliminary emittance measurements are presented.