Cross Section for Electron Capture and Loss by 26-Mev Nitrogen Ions

Electron capture and loss cross sections were measured for 26-Mev nitrogen ions in Zapon. Charge groups, separated by the fringing magnetic field of the cyclotron, were passed through Zapon foils sufficiently thin so that charge equilibrium was not achieved. The relative intensities of the nonequilibrium charge distributions were analyzed to determine the ratios of the cross sections. It was found that σ₅₆σ₆₇=2.6, σ₅₆σ₆₅=3.8, and σ₆₇σ₇₆=0.78. If it is assumed that the average atom in Zapon has a mass of 14, the cross sections for electron capture and loss for 26-Mev nitrogen ions are, in cm²/atom: σ₅₆=7.6×10^-18, σ₆₅=2.0×10^-18, σ₆₇=2.9×10^-18, σ₇₆=3.8×10^-18. Nonequilibrium charge distributions as a function of foil thickness are given for initial beams consisting entirely of any one of the ion groups N⁷⁺, N⁶⁺, or N⁵⁺.