Determination of electron-loss cross sections for negative hydrogen ions in gases using polarized projectiles

A method for the determination of the cross-section ratioσ _?10/(σ _?11+ (σ _?10) for hydrogen ions in gases is described; the indices refer to the initial and final charge state. The method is based on the fact that a polarized hydrogen ion beam loses a certain amount of its initial polarization during charge exchange from the negative to positive state in the stripper canal of a tandem accelerator. Combined with the beam-attenuation method the individual electron-stripping cross sections (σ _?11, (σ _?10 and (σ _?01 can be obtained.