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bunching

Paper Title Other Keywords Page
MOPCH008 Considerations for Double Pulse Lasing from the BESSY-FEL FEL, electron, simulation, laser 62
 
  • K. Goldammer, B.C. Kuske, A. Meseck
    BESSY GmbH, Berlin
  BESSY proposes a linac-based High-Gain Harmonic-Generation (HGHG) free electron laser (FEL) facility with three independent FEL lines. Two to four HGHG stages downconvert the initial seed wavelength (230nm to 460nm) to the desired radiation range (1.24nm to 51nm). High FEL gain is ensured as the seed radiation interacts only with unperturbed parts of the electron bunch in every HGHG-stage. This so-called fresh-bunch-technique relies on dipole chicanes that delay the electron bunches relative to the radiation. Fresh-bunch chicanes are incorporated prior to each modulator in the BESSY-FEL allowing the bunch to completely travel through all undulators. However, simulations show that bunch parts that have previously lased generate a noticeable radiation power level in the final amplifiers. This motivated simulation studies on the significance and applicability of such inherent additional pulses. It is revealed that the BESSY-FEL provides the opportunity to deliver double pulses at the FEL exit being of high interest to the user community. Temporal seperation and intensity levels can be controlled by carefully optimising the properties of the magnetic chicanes.  
 
MOPLS101 Beam Dynamics and First Operation of the Sub-harmonic Bunching System in the CTF3 Injector CTF3, simulation, CERN, linac 795
 
  • P. Urschütz, H.-H. Braun, G. Carron, R. Corsini, S. Doebert, T. Lefevre, G. McMonagle, J. Mourier, J.P.H. Sladen, F. Tecker, L. Thorndahl, C.P. Welsch
    CERN, Geneva
  The CLIC Test Facility CTF3, built at CERN by an international collaboration, aims at demonstrating the feasibility of the CLIC scheme by 2010. The CTF3 drive beam generation scheme relies on the use of a fast phase switch of a sub-harmonic bunching system in order to phase-code the bunches. The amount of charge in unwanted satellite bunches is an important quantity, which must be minimized. Beam dynamics simulations have been used to study the problem, showing the limitation of the present CTF3 design and the gain of potential upgrades. In this paper the results are discussed and compared with beam measurements taken during the first operation of the system.  
 
MOPLS129 Integration of the PHIN RF Gun into the CLIC Test Facility emittance, CTF3, gun, CERN 861
 
  • S. Doebert
    CERN, Geneva
  CERN is a collaborator within the European PHIN project, a joint research activity for Photo injectors within the CARE program. The scope of this project is to build an RF Gun equipped with high quantum efficiency Cs2Te cathodes and a laser to produce the nominal beam for the CLIC Test Facility (CTF3). The nominal beam for CTF3 has an average current of 3.5 A, 1.5 GHz bunch repetition frequency and a pulse length of 1.5 us (2310 bunches) with quite tight stability requirements. In addition a phase shift of 90 deg is needed after each train of 140 ns for the special CLIC combination scheme. This RF Gun will be tested at CERN in fall 2006 and should be integrated as a new injector into the CTF3 linac, replacing the existing injector consisting of a thermionic gun and a subharmonic bunching system. The paper studies the optimal integration into the machine trying to optimize transverse and longitudinal phase space of the beam while respecting the numerous constraints of the existing accelerator. The presented scheme uses emittance compensation and velocity bunching to fulfill the requirements.  
 
WEPLS049 The Design of a Hybrid Photoinjector for High Brightness Beam Applications gun, simulation, coupling, emittance 2487
 
  • D. Alesini, M. Ferrario, V. Fusco, B. Spataro
    INFN/LNF, Frascati (Roma)
  • L. Ficcadenti, A. Mostacci, L. Palumbo
    Rome University La Sapienza, Roma
  • B. O'Shea, J.B. Rosenzweig, G. Travish
    UCLA, Los Angeles, California
  In this paper, we illustrate the electromagnetic and beam dynamics design procedure of a new class of photoinjector, a hybrid standing/traveling wave structure. In this device a standing wave RF gun section is integrated with a downstream traveling wave structure through a coupling cell that feeds simultaneously the two sections. We discuss the advantages in RF and beam performance of the hybrid photoinjector compared to conventional systems. The electromagnetic design has been performed using the 2D and 3D electromagnetic codes Superfish and HFSS. Results of beam dynamics simulations in different operating conditions are also discussed.  
 
THPCH007 Development of a High Current Proton Linac for FRANZ rfq, emittance, proton, beam-losses 2799
 
  • C. Zhang, A. Schempp
    IAP, Frankfurt-am-Main
  The FRANZ Facility, a planned worldwide unique pulsed neutron source, will be built at Frankfurt University. A single RFQ or an RFQ-IH combination working at 175MHz will be used to accelerate a 200mA proton beam to the energy which can meet the demands of required neutron production. The beam dynamics study has been performed to design a flexible, short-structure and low-beam-loss RFQ accelerator. The design results and relative analyses are presented.