Ion core parameters in the bending magnets of electron storage rings

Abstract

Effective methods of decreasing the density of ions neutralizing the space charge of electron beams in storage rings are improving the vacuum conditions and application of the clearing electrodes. There are presented the results of both theoretical and numerical studies of the relation of ion density with the density and composition of the residual gas in the vacuum chamber. Steady state of the ion core was investigated for the case of the dipole magnetic field and electrostatic clearing electrodes. Analytical expressions describing the longitudinal, the vertical ad the horizontal shapes of the core density are presented. It is shown that the core density and ionizing rates of ions is determined by the gas-to-beam density ratio. Transverse density of ions is much sharper then the beam density, and the ion induced force is sufficiently nonlinear.