Tech-X, Boulder, Colorado, USA
BNL, Upton, Long Island, New York, USA
Next generation ion colliders will require effective cooling of high-energy hadron beams. Coherent electron cooling (CEC) can in principle cool relativistic hadron beams on orders-of-magnitude shorter time scales than other techniques. We present Vlasov-Poisson and delta-f particle-in-cell (PIC) simulations of a CEC modulator section. These simulations correctly capture the subtle time and space evolution of the density and velocity wake imprinted on the electron distribution via anisotropic Debye shielding of a drifting ion. We consider 1D and 2D reduced versions of the problem, and compare the exact solutions of Wang and Blaskiewicz with Vlasov-Poisson and delta-f PIC simulations. We also consider interactions under non-ideal conditions where there is a density gradient in the electron distribution, and present simulations of the ion wake.
* V.N. Litvinenko and Y.S. Derbenev, Phys. Rev. Lett. 102, 114801 (2009).
Tech-X, Boulder, Colorado, USA
BNL, Upton, Long Island, New York, USA
PSI, Villigen, Switzerland
Increasing the luminosity of ion beams in particle accelerators is critical for the advancement of nuclear and particle physics. Coherent electron cooling promises to cool high-energy hadron beams significantly faster than electron cooling or stochastic cooling. Here we show simulations of a single pass through a coherent electron cooler, which consists of a modulator, a free-electron laser, and a kicker. In the modulator the electron beam copropagates with the ion beam, which perturbs the electron beam density according to the ion positions. The FEL, which both amplifies and imparts wavelength-scale modulation on the electron beam. The strength of modulated electric fields determines how much they accelerate or decelerate the ions when electron beam recombines with the dispersion-shifted hadrons in the kicker region. From these field strengths we estimate the cooling time for a gold ion with a specific longitudinal velocity.
* Vladimir N. Litvinenko, Yaroslav S. Derbenev, Physical Review Letters 102, 114801 (2009)
BNL, Upton, Long Island, New York, USA
Tech-X, Boulder, Colorado, USA
JLAB, Newport News, Virginia, USA
Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders*. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using one of JLab’s SRF cryo-modules. In this paper, we describe the experimental setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC.
* Vladimir N. Litvinenko, Yaroslav S. Derbenev, Physical Review Letters 102, 114801
