BNL, Upton, Long Island, New York
We propose a demonstration experiment at Accelerator Test Facility at BNL on suppression of spontaneous undulator radiation from an electron beam. We describe the method, the proposed layout and possible schedule.
BNL, Upton, Long Island, New York
FEL-based coherent electron cooling offers a new avenue to achieve high luminosities in high energy colliders such as RHIC, LHC, and eRHIC. Traditional FEL treatments treat the FEL as an amplifier of optical waves with specific initial conditions, and obtain the resulting field. This new approach requires knowledge of the phase space distribution of the electron cloud in the FEL. We present 1D analytical results for the phase space distribution of an electron cloud with an arbitrary initial current profile, and discuss approaches of expanding to 3D results.
BNL, Upton, Long Island, New York
Short noise in electron beam distribution is the main source of noise in high-gain FEL amplifiers ranging single- and multi-stage HGHG FEL to FEL amplifier for Coherent Electron Cooler. This noise also imposes a fundamental limit on FEL gain to about six orders of magnitude, after which SASE FEL does saturate. There is a number of advantages can be gain if short noise in the electron beam and corresponding spontaneous radiation are strongly suppressed. A traditional passive method used in low-energy microwave electronic devices* has a number of significant limitations and hardly can be used for highly inhomogeneous beams used in modern high gain FELs. In this paper we present a novel active method of suppressing the short noise in relativistic electron beams by many orders of magnitude. We present theoretical description of the process, the fundamental limitation of the process. We also discuss potential experiment demonstrating the proposed technique.
* I.e. waiting for plasma oscillation to transfer short noise in the density distribution into the velocity noise. This technique is very successful for low-energy DC beams with constant peak current.
