W. Meckbach

Convoy-electron emission induced by multiple collisions of H{sup +} and H{sup 0} on a thick He target

We present double-differential electron distributions, measured in the neighborhood of the velocity of the emerging projectiles, for 45-keV H{sup +} and H{sup 0} incident on a He target. Target thicknesses range from single-collision conditions through a multiple-collision regime up to charge equilibrium in the emerging beam. The convoy-electron emission yield is determined as a function of target thickness. Using a simple rate equation and known cross sections for charge exchange and electron scattering, approximate agreement with experiment is obtained. A smaller electron-He scattering cross section improves this agreement. This result could be interpreted as due to the effect of the projectile Coulomb field in the transport of the electrons. {copyright} {ital 1997} {ital The American Physical Society}