Author: Broemmelsiek, D.R.
Paper Title Page
MOPA34 Noise in Intense Electron Bunches 128
 
  • S. Nagaitsev, D.R. Broemmelsiek, J.D. Jarvis, A.H. Lumpkin, J. Ruan, G.W. Saewert, R.M. Thurman-Keup
    Fermilab, Batavia, Illinois, USA
  • Z. Huang, G. Stupakov
    SLAC, Menlo Park, California, USA
  • Y.K. Kim
    University of Chicago, Chicago, Illinois, USA
  
  We report on our investigations into density fluctuations in electron bunches. Noise and density fluctuations in relativistic electron bunches, accelerated in a linac, are of critical importance to various Coherent Electron Cooling (CEC) concepts as well as to free-electron lasers (FELs). For CEC, the beam noise results in additional diffusion that counteracts cooling. In SASE FELs, a microwave instability starts from the initial noise in the beam and eventually leads to the beam microbunching yielding coherent radiation, and the initial noise in the FEL bandwidth plays a useful role. In seeded FELs, in contrast, such noise interferes with the seed signal, so that reducing noise at the initial seed wavelength would lower the seed laser power requirement. Status of the project will be presented.  
poster icon Poster MOPA34 [0.638 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA34  
About • Received ※ 10 August 2022 — Revised ※ 11 August 2022 — Accepted ※ 14 August 2022 — Issue date ※ 24 August 2022
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FRXD1
 Demonstration of Optical Stochastic Cooling in an Electron Storage Ring  
 
  • J.D. Jarvis, D.R. Broemmelsiek, K. Carlson, D.R. Edstrom, V.A. Lebedev, S. Nagaitsev, H. Piekarz, A.L. Romanov, J. Ruan, J.K. Santucci, G. Stancari, A. Valishev
    Fermilab, Batavia, Illinois, USA
  • S. Chattopadhyay, A.J. Dick, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • I. Lobach
    University of Chicago, Chicago, Illinois, USA
  
  Optical stochastic cooling (OSC), proposed nearly thirty years ago, replaces the conventional microwave elements of stochastic cooling (SC) with optical-frequency analogs, such as undulators, optical lenses and optical amplifiers. Here we discuss the first experimental observation of OSC, which was performed at the Fermi National Accelerator Laboratory’s Integrable Optics Test Accelerator (IOTA) with 100-MeV electrons and a radiation wavelength of 950 nm. The experiment employed a non-amplified configuration of OSC and achieved a longitudinal damping rate close to one order of magnitude larger than the beam’s natural damping due to synchrotron radiation. The integrated system demonstrated sub-femtosecond stability and a bandwidth of ~20 THz, a factor of ~2000-times higher than conventional microwave SC systems. Coupling to the transverse planes enabled simultaneous cooling of the beam in all degrees of freedom. This first demonstration of SC at optical frequencies serves as a foundation for more advanced experiments with high-gain optical amplification and advances opportunities for future operational OSC systems at colliders and other accelerator facilities.  
slides icon Slides FRXD1 [32.041 MB]  
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