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bunching

Paper Title Other Keywords Page
MOPKF010 The Output Performance of the BESSY Multi-stage HGHG-FEL undulator, electron, polarization, laser 318
 
  • A. Meseck, M. Abo-Bakr, B.C. Kuske
    BESSY GmbH, Berlin
  The BESSY soft X-ray FEL is planned as a High Gain Harmonic Generatio(HGHG) FEL multi-user facility covering the VUV to soft X-ray spectral range(0.02 keV - 1. keV). A photoinjector and a superconducting 2.3GeV CW linac will feed three independent HGHG-FEL-lines. As the efficiency of the interaction between the radiation and the electron beam is higher in a helical undulator, one would tend to prefer such a device for the HGHG scheme. Also a higher K-value of the modulators seems to be advantageous. This is not necessarily the case. We present simulation studies for the BESSY-HGHG-FELs and discuss the output performance for ‘‘helical stages'' and increased K value of the modulators.  
 
MOPKF011 Output Variability of the BESSY Soft X-ray FEL electron, radiation, undulator, simulation 321
 
  • A. Meseck, M. Abo-Bakr, B.C. Kuske
    BESSY GmbH, Berlin
  The BESSY soft X-ray FEL is planned as a High Gain Harmonic Generation HGHG) FEL multi-user facility covering the VUV to soft X-ray spectral rang(0.02 keV - 1 keV). A photoinjector and a superconducting $2.3\,GeV$ CW linac will feed three independent HGHG-FEL-lines. Depending on the optimisation criteria, it is possible to obtain either maximum output power or pure spectrum from the same HGHG-line. We present simulation studies for the BESSY-HGHG-FELs and discuss the possible variability of the output performance.  
 
MOPLT062 The Design of a Prototype RF Compressor for High Brightness Electron Beams electron, RF-structure, extraction, injection 698
 
  • D. Giove, F. Alessandria, A. Bacci, C. De Martinis, M. Mauri
    INFN/LASA, Segrate (MI)
  • D. Alesini, M. Ferrario, A. Gallo, F. Marcellini
    INFN/LNF, Frascati (Roma)
  • L. Serafini
    INFN-Milano, Milano
  The generation of sub-ps electron bunches with low transverse emittance at nC charge level is a crucial requirement in the design of injectors for short wavelength FEL's. The technique of velocity bunching has been by now experimentally proven in various laboratories, where bunches below the ps bunch length were obtained: however, preservation of a low transverse emittance after the bunch compression is still to be demonstrated. To this aim, the use a slow wave RF structure as a rectilinear compressor has been proposed in the past to overcome the inherent difficulties of magnetic compressors. In this paper we will review the work carried out in the last 2 years and focused on the design a RF compressor based on a 3 GHz slow-wave copper structure. The rationale of the conceptual design along with a description of the main experimental activities will be presented and the future application of such a scheme to the SPARC project will be discussed.  
 
TUPKF006 Custom Design of Medium Energy Linear Accelerator Systems linac, electron, ion, proton 965
 
  • K. Dunkel, M. Pekeler, C. Piel, H.P. Vogel, P. vom Stein
    ACCEL, Bergisch Gladbach
  Based on customer requirements ACCEL Instruments is designing and building medium energy turn-key Linear Accelerator Systems for scientific applications. Within this paper design and performance of third generation synchrotron light source electron injector linacs will be presented. Further the design of a medium energy light ion linear accelerator will be discussed. This light ion accelerator is designed with independently phased superconducting rf cavities for cw operation and acceleration of different particle species and a variable Energy output.  
 
TUPLT001 Beam Dynamics in 100 MeV S-Band Linac for CANDLE linac, emittance, electron, gun 1129
 
  • B. Grigoryan, V.M. Tsakanov
    CANDLE, Yerevan
  The report presents the results of the beam dynamics study in 100 MeV S-band linear accelerator foreseen as an injector for the CANDLE light source. An impact of the excited longitudinal and transverse wake fields on the particle energy spread and the beam transverse emittance are given.  
 
TUPLT133 Test Results of Injector Based on Resonance System with Evanescent Oscillations electron, resonance, cathode, emittance 1437
 
  • S.A. Perezhogin, M.I. Ayzatskiy, E.Z. Biller, K. Kramarenko, V.A. Kushnir, V.V. Mytrochenko, Z.V. Zhiglo
    NSC/KIPT, Kharkov
  Report presents results of tune-up and tests of the compact electron S ? band injector consisting of the low-voltage diode electron gun and the bunching system based on the resonant system with the evanescent oscillation. In the considered bunching system electrical field increased from beam entrance to an exit of the buncher. The injector designed for bunching of electron beam with initial energy of 25 keV and pulse current of 300 mA and accelerating it to the energy of 1 MeV.  
 
TUPLT162 Computation of the Longitudinal Space Charge Effect in Photoinjectors simulation, linac, space-charge, laser 1506
 
  • C. Limborg-Deprey, P. Emma, Z. Huang, J.J. Welch, J. Wu
    SLAC, Menlo Park, California
  The LCLS Photoinjector produces a 100A, 10 ps long electron bunch which is later compressed down to 100 fs to produce the peak current required for producing SASE radiation. SASE saturation will be reached in the LCLS only if the emittance and uncorrelated energy spread remain respectively below 1.2 mm.mrad and 5. 10-4. This high beam quality will not be met if the Longitudinal Space Charge (LSC) instability develops in the injector and gets amplified in the compressors. The Longitudinal Space Charge instability originates in the injector beamline, from an initial modulation of the current density. Numerical computations, performed with Multiparticle Space Charge tracking codes, showing the evolution of the longitudinal phase space along the LCLS Photoinjector beamline, are presented. Those results are compared with an analytical model for various regimes of energy and acceleration. This study justifies the necessity to insert a "laser heater" in the LCLS Photoinjector beamline to warm up the beam and thus prevent the amplification of the LSC instability in the compressors. Numerical calculations of the 'laser heater' performances are presented.