Electron loss cross sections of high velocity H-like ions in carbon

Abstract

The attenuation of hydrogen atoms and H-like He, Li, C and O ions of about 10-MeV/amu due to the electron loss collisions in thin carbon foils was measured as a function of foil thickness. At the thinner foil region, the incident beams attenuated exponentially as the foil thickness increased. From the attenuation rates, we have determined the electron loss cross sections of the ground state H-like ions. The obtained cross sections are larger than the theoretical predictions based on the Born approximation, especially for projectiles of higher atomic number. They can be well explained quantitatively taking account of the contribution from the projectile excitation which leads to the ionization by the subsequent collision in the foils.