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single-bunch

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WEOA003 First Lasing and Initial Operation of a Circularly Polarized Optical Klystron OK-5 FEL and a Variably Polarized Distributed Optical Klystron DOK-1 FEL at Duke fel, wiggler, lasing, lattice 407
 
  • Y.K. Wu, J. Li, S. Mikhailov, V. Popov
    DU/FEL, Durham, North Carolina
  • N. Gavrilov, G. Kulipanov, O.A. Shevchenko, N. Vinokurov, P. Vobly
    BINP SB RAS, Novosibirsk
  
 

Funding: This work is supported by the U.S. AFOSR MFEL grant F49620-001-0370 and by U.S. DOE grant DE-FG05-91ER40665.

To improve the capability and performance of its light sources, the Duke FEL lab (DFELL) is upgrading its storage ring based FEL by replacing the existing linearly polarized OK-4 FEL with the next generation OK-5 FEL which is capable of delivering both linearly and circularly polarized light. To reduce and manage the risk associated with this project, the FEL upgrade is carried out in three phases. In the second phase of upgrade in 2005, two OK-5 wigglers are installed in a specially designed lattice where OK-4 wigglers remain, forming a distributed optical klystron FEL with hybrid wiggler magnets. In this paper, we report our commissioning experience of this distributed optical klystron FEL, including its first lasing in visible wavelengths and measured lasing spectra and power. We will also present our first experimental results on the FEL polarization manipulation using OK-4 and OK-5 wigglers. In addition, we report the performance enhancement of the Compton gamma-ray source driven by this FEL and initial FEL operation experience for user applications.

   
    
THPP044 Emittance Growth due to Short-Range Transverse Wakefields in the FERMI Linac linac, emittance, fel, focusing 568
 
  • P. Craievich, S. Di Mitri
    ELETTRA, Basovizza, Trieste
  
 

The FEL project FERMI@ELETTRA will use the existing Linac, upgraded to 1.2 GeV, to produce VUV radiation between 100-10 nm. FEL operations require a high quality beam in terms of the bunch energy spread and emittance. In this paper we present an analytical study based on a continuum model to describe the transverse motion of a single bunch. Such a study allows predicting the emittance growth under the combined influence of short-range transverse wakefields, injection offset, initial emittance and misaligned accelerating sections. We also report a comparison between analytical and numerical (tracking code) results.